Commit Graph

654 Commits

Author SHA1 Message Date
Alex Brainman 20832e6d4b cmd/link: introduce and use peFile and peStringTable
Change-Id: Icd13b32d35cde474c9292227471f916a64af88eb
Reviewed-on: https://go-review.googlesource.com/55257
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-16 05:09:08 +00:00
David du Colombier 583a941d4e cmd/link: skip TestSizes on Plan 9
TestSizes has been added in CL 55551. This test is
failing on Plan 9 because executables don't have
a DWARF symbol table.

Fixes #21453.

Change-Id: I560611b49aea5417e8c5ac0cec6c7882bd9f8335
Reviewed-on: https://go-review.googlesource.com/55692
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
2017-08-15 10:10:42 +00:00
Russ Cox ef6978b218 cmd/link: implement R_X86_64_PC64 relocations
Change-Id: I1d7bd5cff7350a4e0f78b8efc8406e79c74732d1
Reviewed-on: https://go-review.googlesource.com/55370
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-15 04:20:44 +00:00
Hiroshi Ioka 1ee701e857 cmd/link: improve error message
ld.SymKind and objabi.RelocType have string representations,
which is human friendly. Prefer to use it.

Change-Id: I458ee0ca5866be0db8462c36cd053561a8206c95
Reviewed-on: https://go-review.googlesource.com/55253
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-15 00:28:27 +00:00
Hiroshi Ioka 90ffc40e4f cmd/link: correct Mach-O file flag
Only set MH_NOUNDEFS if there are no undefined symbols.
Doesn't seem to matter, but may as well do it right.

Change-Id: I6c472e000578346c28cf0e10f24f870e3a0de628
Reviewed-on: https://go-review.googlesource.com/55310
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-15 00:13:10 +00:00
Keith Randall f4abbc0e61 cmd/link,compile: Provide size for func types
They are currently not given a size, which makes the DWARF reader
very confused. Particularly things like [4]func() get a size of -4, not 32.

Fixes #21097

Change-Id: I01e754134d82fbbe6567e3c7847a4843792a3776
Reviewed-on: https://go-review.googlesource.com/55551
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-14 23:53:27 +00:00
Hiroshi Ioka 1f8433c66a cmd/link: don't link the same dylib multiple times
Also, unexport Machoadddynlib

n=`go test -c crypto/x509 && otool -l x509.test | grep libSystem | wc -l`

Before this CL, n = 3.
After this CL, n = 1.

on my environment.

Change-Id: Ic7b8157435cc85086404860dc6c84eb0aecc5d19
Reviewed-on: https://go-review.googlesource.com/44771
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Avelino <t@avelino.xxx>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-14 18:48:28 +00:00
Hiroshi Ioka b7c600d6ba cmd/go, cmd/link: enable buildmode=pie on darwin/amd64
Change some configurations to enable the feature. Also add the test.
This CL doesn't include internal linking support which is tentatively
disabled due to #18968. We could do that another day.

Fixes #21220

Change-Id: I601d2d78446d36332acc70be0d5b9461ac635208
Reviewed-on: https://go-review.googlesource.com/54790
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-14 18:45:21 +00:00
Hiroshi Ioka 5b43bbe63b cmd/link: prefer to use constants in macho.go
We might want to replace some linker's feature by debug/macho in future.
This CL gathers information of required constants.

Change-Id: Iea14abdb32709a4f5404a17874f9c925d29ba999
Reviewed-on: https://go-review.googlesource.com/55252
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-14 05:28:38 +00:00
Hiroshi Ioka 6424c40c22 cmd/link: don't emit default entry symbol in some situations
Also, fix comment.

Change-Id: Ieb7ba21f34730dc51ab45a652d225e4145d4b861
Reviewed-on: https://go-review.googlesource.com/54870
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-14 05:28:22 +00:00
Hiroshi Ioka 342d25fc05 cmd/link: remove redundant switch stmt
Change-Id: I5c4f8dc1e174b3438ef4fb509fac78d6e1b292c9
Reviewed-on: https://go-review.googlesource.com/54791
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Avelino <t@avelino.xxx>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-14 04:44:35 +00:00
Austin Clements 6f6a9398e2 Merge remote-tracking branch 'origin/dev.debug' into master
Change-Id: I85df2745af666b533f4f6f1d06f7c8e137590b5b
2017-08-11 12:17:43 -04:00
Hiroshi Ioka d02647242d cmd/link: check magic header
Change-Id: I84b0e1d86728a76bc6a87fee4accf6fc43d87006
Reviewed-on: https://go-review.googlesource.com/54814
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-11 01:51:34 +00:00
Lynn Boger 3e7abf82e3 cmd/go,cmd/link: support buildmode c-shared on ppc64le
This change enables buildmode c-shared on ppc64le.

A bug was fixed in runtime/rt0_linux_ppc64le.s that was necessary to
make this work.  In _rt0_ppc64le_linux_lib, there is code to store
the value of r2 onto the caller's stack.  However, if this file
is compiled using a build mode that maintains the TOC address in
r2, then instructions will be inserted at the beginning of this
function to generate the r2 value for the callee, not the caller.
That means the r2 value for the callee is stored onto the caller's
stack.  If caller and callee don't have the same r2 values, then
the caller will restore the wrong r2 value after it returns.  This
situation can happen when using dlopen since the caller of this
function will be in ld64.so and will definitely have a different
TOC.

Updates #20756

Change-Id: I6e165e0d0716e73721bbbcc520e8302e4856e3ba
Reviewed-on: https://go-review.googlesource.com/53890
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-09 17:11:38 +00:00
Heschi Kreinick 4c54a047c6 [dev.debug] cmd/compile: better DWARF with optimizations on
Debuggers use DWARF information to find local variables on the
stack and in registers. Prior to this CL, the DWARF information for
functions claimed that all variables were on the stack at all times.
That's incorrect when optimizations are enabled, and results in
debuggers showing data that is out of date or complete gibberish.

After this CL, the compiler is capable of representing variable
locations more accurately, and attempts to do so. Due to limitations of
the SSA backend, it's not possible to be completely correct.

There are a number of problems in the current design. One of the easier
to understand is that variable names currently must be attached to an
SSA value, but not all assignments in the source code actually result
in machine code. For example:

  type myint int
  var a int
  b := myint(int)
and
  b := (*uint64)(unsafe.Pointer(a))

don't generate machine code because the underlying representation is the
same, so the correct value of b will not be set when the user would
expect.

Generating the more precise debug information is behind a flag,
dwarflocationlists. Because of the issues described above, setting the
flag may not make the debugging experience much better, and may actually
make it worse in cases where the variable actually is on the stack and
the more complicated analysis doesn't realize it.

A number of changes are included:
- Add a new pseudo-instruction, RegKill, which indicates that the value
in the register has been clobbered.
- Adjust regalloc to emit RegKills in the right places. Significantly,
this means that phis are mixed with StoreReg and RegKills after
regalloc.
- Track variable decomposition in ssa.LocalSlots.
- After the SSA backend is done, analyze the result and build location
lists for each LocalSlot.
- After assembly is done, update the location lists with the assembled
PC offsets, recompose variables, and build DWARF location lists. Emit the
list as a new linker symbol, one per function.
- In the linker, aggregate the location lists into a .debug_loc section.

TODO:
- currently disabled for non-X86/AMD64 because there are no data tables.

go build -toolexec 'toolstash -cmp' -a std succeeds.

With -dwarflocationlists false:
before: f02812195637909ff675782c0b46836a8ff01976
after:  06f61e8112a42ac34fb80e0c818b3cdb84a5e7ec
benchstat -geomean  /tmp/220352263 /tmp/621364410
completed   15 of   15, estimated time remaining 0s (eta 3:52PM)
name        old time/op       new time/op       delta
Template          199ms ± 3%        198ms ± 2%     ~     (p=0.400 n=15+14)
Unicode          96.6ms ± 5%       96.4ms ± 5%     ~     (p=0.838 n=15+15)
GoTypes           653ms ± 2%        647ms ± 2%     ~     (p=0.102 n=15+14)
Flate             133ms ± 6%        129ms ± 3%   -2.62%  (p=0.041 n=15+15)
GoParser          164ms ± 5%        159ms ± 3%   -3.05%  (p=0.000 n=15+15)
Reflect           428ms ± 4%        422ms ± 3%     ~     (p=0.156 n=15+13)
Tar               123ms ±10%        124ms ± 8%     ~     (p=0.461 n=15+15)
XML               228ms ± 3%        224ms ± 3%   -1.57%  (p=0.045 n=15+15)
[Geo mean]        206ms             377ms       +82.86%

name        old user-time/op  new user-time/op  delta
Template          292ms ±10%        301ms ±12%     ~     (p=0.189 n=15+15)
Unicode           166ms ±37%        158ms ±14%     ~     (p=0.418 n=15+14)
GoTypes           962ms ± 6%        963ms ± 7%     ~     (p=0.976 n=15+15)
Flate             207ms ±19%        200ms ±14%     ~     (p=0.345 n=14+15)
GoParser          246ms ±22%        240ms ±15%     ~     (p=0.587 n=15+15)
Reflect           611ms ±13%        587ms ±14%     ~     (p=0.085 n=15+13)
Tar               211ms ±12%        217ms ±14%     ~     (p=0.355 n=14+15)
XML               335ms ±15%        320ms ±18%     ~     (p=0.169 n=15+15)
[Geo mean]        317ms             583ms       +83.72%

name        old alloc/op      new alloc/op      delta
Template         40.2MB ± 0%       40.2MB ± 0%   -0.15%  (p=0.000 n=14+15)
Unicode          29.2MB ± 0%       29.3MB ± 0%     ~     (p=0.624 n=15+15)
GoTypes           114MB ± 0%        114MB ± 0%   -0.15%  (p=0.000 n=15+14)
Flate            25.7MB ± 0%       25.6MB ± 0%   -0.18%  (p=0.000 n=13+15)
GoParser         32.2MB ± 0%       32.2MB ± 0%   -0.14%  (p=0.003 n=15+15)
Reflect          77.8MB ± 0%       77.9MB ± 0%     ~     (p=0.061 n=15+15)
Tar              27.1MB ± 0%       27.0MB ± 0%   -0.11%  (p=0.029 n=15+15)
XML              42.7MB ± 0%       42.5MB ± 0%   -0.29%  (p=0.000 n=15+15)
[Geo mean]       42.1MB            75.0MB       +78.05%

name        old allocs/op     new allocs/op     delta
Template           402k ± 1%         398k ± 0%   -0.91%  (p=0.000 n=15+15)
Unicode            344k ± 1%         344k ± 0%     ~     (p=0.715 n=15+14)
GoTypes           1.18M ± 0%        1.17M ± 0%   -0.91%  (p=0.000 n=15+14)
Flate              243k ± 0%         240k ± 1%   -1.05%  (p=0.000 n=13+15)
GoParser           327k ± 1%         324k ± 1%   -0.96%  (p=0.000 n=15+15)
Reflect            984k ± 1%         982k ± 0%     ~     (p=0.050 n=15+15)
Tar                261k ± 1%         259k ± 1%   -0.77%  (p=0.000 n=15+15)
XML                411k ± 0%         404k ± 1%   -1.55%  (p=0.000 n=15+15)
[Geo mean]         439k              755k       +72.01%

name        old text-bytes    new text-bytes    delta
HelloSize         694kB ± 0%        694kB ± 0%   -0.00%  (p=0.000 n=15+15)

name        old data-bytes    new data-bytes    delta
HelloSize        5.55kB ± 0%       5.55kB ± 0%     ~     (all equal)

name        old bss-bytes     new bss-bytes     delta
HelloSize         133kB ± 0%        133kB ± 0%     ~     (all equal)

name        old exe-bytes     new exe-bytes     delta
HelloSize        1.04MB ± 0%       1.04MB ± 0%     ~     (all equal)

Change-Id: I991fc553ef175db46bb23b2128317bbd48de70d8
Reviewed-on: https://go-review.googlesource.com/41770
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2017-07-27 20:19:44 +00:00
Heschi Kreinick 59fe2fbfe5 [dev.debug] cmd/link: let the linker combine .debug_ranges, remove globals
The linker is pretty good at combining a bunch of symbols into a
section, so let it do .debug_ranges the normal way. Along the way,
remove a bunch of globals that were only used by one function that would
only be called once per invocation.

Change-Id: I1a528a438b193c41e7c444e8830516b07f11affc
Reviewed-on: https://go-review.googlesource.com/43890
Reviewed-by: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-07-26 18:39:50 +00:00
Ian Lance Taylor 6bb88fc280 cmd/link: use full link, not compile, to test for -no-?pie
This avoids an error from clang when using -nopie during compilation,
and permits us to check that the entire build succeeds.

Updates #21042

Change-Id: I2e6c7d5c97a85c223ed3288622bbb58ce33b8774
Reviewed-on: https://go-review.googlesource.com/50874
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-07-24 17:50:57 +00:00
Ian Lance Taylor 9e859d5e9c cmd/go, cmd/link: if -no-pie doesn't work, try -nopie
GCC says -no-pie, clang says -nopie.

Fixes #21042

Change-Id: Iadc83ea7a48ea0debc5064c1ee8da4ebff752044
Reviewed-on: https://go-review.googlesource.com/49710
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-07-20 18:52:06 +00:00
Austin Clements c2c07c7989 runtime: always use 2MB stacks on 64-bit Windows
Currently, Windows stacks are either 128kB or 2MB depending on whether
the binary uses cgo. This is because we assume that Go system stacks
and the small amount of C code invoked by the standard library can
operate within smaller stacks, but general Windows C code assumes
larger stacks.

However, it's easy to call into arbitrary C code using the syscall
package on Windows without ever importing cgo into a binary. Such
binaries need larger system stacks even though they don't use cgo.

Fix this on 64-bit by increasing the system stack size to 2MB always.
This only costs address space, which is free enough on 64-bit to not
worry about. We keep (for now) the existing heuristic on 32-bit, where
address space comes at more of a premium.

Updates #20975.

Change-Id: Iaaaa9a2fcbadc825cddc797aaaea8d34ef8debf2
Reviewed-on: https://go-review.googlesource.com/49331
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
2017-07-18 14:35:35 +00:00
Michael Pratt 123fd4640a cmd/link: skip R_ADDR relocs in .rela.plt for internal PIE
ld.addpltsym adds an R_X86_64_JMP_SLOT dynamic relocation to .rela.plt
and uses Addaddrplus to reference the GOT in Elf64_Rela.r_offset.

Addaddrplus results in an R_ADDR relocation, which here we transform
into an R_X86_64_64 dynamic relocation. This is wrong for several
reasons:

1. .rela.plt is not a writable, relro section. It is mapped read-only,
   causing the dynamic linker to segfault when it tried to handle the
   relocation. This was the immediate cause of internal PIE cgo
   crashes.

2. Relocations targetting other reloc sections are, as far as I can
   tell, undefined behavior in the ELF spec and are unlikely to be a
   good idea.

3. Even if the relocation did work, it isn't what we want. The
   relocation, if successfully handled, would have put an absolute
   address as the JMP_SLOT offset, but it should be the offset from the
   beginning of the binary, just like any other relocation. What we want
   is a statically resolved R_ADDR relocation, just as is used below for
   the R_X86_64_64 relocation.

Skipping the .rela.plt allows reloc() to handle these R_ADDR
relocations.

With this CL, internal PIE cgo binaries work.

Updates #18968

Change-Id: Ie74e6fe249e88150baa0e340b1cb128cf7f28673
Reviewed-on: https://go-review.googlesource.com/47837
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-07-09 19:23:41 +00:00
Lynn Boger 738739f565 cmd/link: implement trampolines for ppc64le with ext linking
When using golang on ppc64le there have been issues
when building executables that generate extremely large text
sections.  This is due to the call instruction and the limitation
on the offset field, which is smaller than most platforms.  If the
size of the call target offset is too big for the offset field in
the call instruction, then link errors can occur.

The original solution to this problem in golang was to split the
text section when it became too large, allowing the external (GNU)
linker to insert the necessary stub to handle the long call.  That
worked fine until the another size limit for the program size was hit,
where a plt_branch was created instead of a long branch.  In that case
the plt_branch code sequence expects r2 to contain the address of the
TOC, but when golang creates dynamic executables by default
(-buildmode=exe) r2 does not always contain the address of the TOC
and as a result when building programs that reach this extremely
large size, a runtime SEGV or SIGILL can occur due to branching to a bad
address.

When using internal linking, trampolines are generated to handle the
long calls but the text sections are not split.  With this change,
text sections will still be split approrpriately with external linking
but if the buildmode being used does not maintain r2 as the TOC
addresses, then trampolines will be created for those calls.

Fixes #20497

Change-Id: If5400b0f86c2c08e106b332be6db0b259b07d93d
Reviewed-on: https://go-review.googlesource.com/45130
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2017-06-14 14:12:11 +00:00
Russ Cox 4f2269edbd cmd/link: add -importcfg to specify import resolution
Adds the ability to specify the file location of each imported package,
like in the -importcfg added to cmd/compile in a related CL.
In effect, -importcfg is a generalization of and supersedes -installsuffix
and -L. Of course, those flags will continue to be supported, for
compatibility with other tools.

Having this flag in Go 1.9 will let us try some experiments involving
package management without needing guinea pigs to build a custom
Go toolchain.

This flag also helps with #14271 at some later point.

For #20579.

Change-Id: Ie4c171bcd3aa2faa446ac340e36516f2f9853882
Reviewed-on: https://go-review.googlesource.com/44851
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-06-06 19:49:58 +00:00
Russ Cox 51711d1429 cmd/link: fix accidentally-quadratic library loading
Programs built from N libraries required O(N²) time to do the
deduplication checks, even if there were never any duplicates.
In most programs N is small enough not to worry, but this may
affect large programs.

Noticed by inspection, not any specific bug report.

Fixes #20578.

Change-Id: Ic4108f1058be39da990a79b1e0b8ce95fde44cef
Reviewed-on: https://go-review.googlesource.com/44852
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-06-05 19:56:34 +00:00
Dmitry Savintsev 4c86f7bd49 cmd/link: fix left-over reference to reflect.c
Replaced ../gc/reflect.c with
cmd/compile/internal/gc/reflect.go.

Fixes #20525

Change-Id: Ibafd36ea446ace5c677df27873a4bbf716a0a9bc
Reviewed-on: https://go-review.googlesource.com/44376
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-05-30 01:10:56 +00:00
Heschi Kreinick b74f01d76f cmd/internal/dwarf: update to DWARF4, emit frame_base
In preparation for CL 41770, upgrade .debug_info to DWARF4, and emit
DW_AT_frame_base on subprograms. This should make no semantic
difference.

Also fix a long-standing bug/inconsistency in puttattr: it didn't
add the addend to ref_addrs. Previously this didn't matter because it
was only used for types, but now it's used for section offsets into
symbols that have multiple entries.

RELNOTE=yes

Change-Id: Ib10654ac92edfa29c5167c44133648151d70cf76
Reviewed-on: https://go-review.googlesource.com/44210
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
2017-05-26 21:29:21 +00:00
Alessandro Arzilli 2ad41a3090 cmd/compile: output DWARF lexical blocks for local variables
Change compiler and linker to emit DWARF lexical blocks in .debug_info
section when compiling with -N -l.

Version of debug_info is updated from DWARF v2 to DWARF v3 since
version 2 does not allow lexical blocks with discontinuous PC ranges.

Remaining open problems:
- scope information is removed from inlined functions
- variables records do not have DW_AT_start_scope attributes so a
variable will shadow other variables with the same name as soon as its
containing scope begins, even before its declaration.

Updates #6913.
Updates #12899.

Change-Id: Idc6808788512ea20e7e45bcf782453acb416fb49
Reviewed-on: https://go-review.googlesource.com/40095
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2017-05-18 23:10:50 +00:00
Alex Brainman b5e964cc1c cmd/link: make sure that runtime.epclntab lives in .text section
Second attempt to fix #14710.

CL 35272 already tried to fix this issue. But CL 35272 assumed
that runtime.epclntab type is STEXT, while it is actually SRODATA.

This CL uses Symbol.Sect.Seg to determine if symbol is part
of Segtext or Segdata.

Fixes #14710

Change-Id: Ic6b6f657555c87a64d2bc36cc4c07ab0591d00c4
Reviewed-on: https://go-review.googlesource.com/42390
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-05-18 05:32:41 +00:00
Alex Brainman 1d44c4e378 cmd/link: actually generate .debug_gdb_scripts section on windows
Adjust finddebugruntimepath to look for runtime/debug.go file
instead of runtime/runtime.go. This actually finds runtime.GOMAXPROCS
in every Go executable (including windows).

I also included "-Wl,-T,fix_debug_gdb_scripts.ld" parameter to gcc
invocation on windows to work around gcc bug (see #20183 for details).

This CL only fixes windows -buildmode=exe, buildmode=c-archive
is still broken.

Thanks to Egon Elbre and Nick Clifton for investigation.

Fixes #20183
Fixes #20218

Change-Id: I5369a4db3913226aef3d9bd6317446856b0a1c34
Reviewed-on: https://go-review.googlesource.com/43331
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-05-15 06:16:19 +00:00
Josh Bleecher Snyder 201fd16568 cmd/link: set Fieldtrack symbol type to SDATA
Fixes #20316

Change-Id: I2553ad9a82dfcb30f020c2a3e37b868111425a20
Reviewed-on: https://go-review.googlesource.com/43151
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-10 19:24:29 +00:00
David Chase 41d0bbdc16 cmd/link: include DW_AT_producer in .debug_info
This can make life easier for Delve (and other debuggers),
and can help them with bug reports.

Sample producer field (from objdump):
<48> DW_AT_producer : Go cmd/compile devel +8a59dbf41a Mon May 8 16:02:44 2017 -0400

Change-Id: I0605843c959b53a60a25a3b870aa8755bf5d5b13
Reviewed-on: https://go-review.googlesource.com/33588
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-05-10 14:47:41 +00:00
Ian Lance Taylor 5331e7e9df cmd/internal/obj, cmd/link: fix st_other field on PPC64
In PPC64 ELF files, the st_other field indicates the number of
prologue instructions between the global and local entry points.
We add the instructions in the compiler and assembler if -shared is used.
We were assuming that the instructions were present when building a
c-archive or PIE or doing dynamic linking, on the assumption that those
are the cases where the go tool would be building with -shared.
That assumption fails when using some other tool, such as Bazel,
that does not necessarily use -shared in exactly the same way.

This CL records in the object file whether a symbol was compiled
with -shared (this will be the same for all symbols in a given compilation)
and uses that information when setting the st_other field.

Fixes #20290.

Change-Id: Ib2b77e16aef38824871102e3c244fcf04a86c6ea
Reviewed-on: https://go-review.googlesource.com/43051
Run-TryBot: Ian Lance Taylor <iant@golang.org>
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Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-05-09 23:36:51 +00:00
Elias Naur 45d42fdcea cmd/link/internal/ld: don't link with -no_pie on darwin/arm64
Ever since CL 33301 linking darwin/arm64 excutables has resulted in
warnings like:

ld: warning: -no_pie ignored for arm64

Remove -no_pie on darwin/arm64.

Change-Id: I9f7685351fa8cce29795283e1a24fc7a6753d698
Reviewed-on: https://go-review.googlesource.com/42815
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2017-05-07 19:12:26 +00:00
Kevin Burke 9058b9ae49 os, cmd/link: fix typos
Also switch "stating" to "statting" to describe applying os.Stat to
a resource; the former is more confusable than the latter.

Change-Id: I9d8e3506bd383f8f1479c05948c03b8c633dc4af
Reviewed-on: https://go-review.googlesource.com/42855
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-07 18:13:02 +00:00
Egon Elbre e94b9d4143 cmd/link/internal/ld: fix external linking on windows
gcc on windows writes invalid location for .debug_gdb_scripts
which causes the executable loading to fail.

Fixes #20183

Change-Id: I5134013bc926b44a55b528f66ab79555855d1f4d
Reviewed-on: https://go-review.googlesource.com/42651
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
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2017-05-06 06:11:31 +00:00
Carlos Eduardo Seo 09b71d563a cmd/internal/obj/ppc64, cmd/link/internal/ppc64: Change function alignment to 16
The Power processor manual states that "Branches not from the last instruction
of an aligned quadword and not to the first instruction of an aligned quadword
cause inefficiencies in the IBuffer". This changes the function alignment from 8
to 16 bytes to comply with that.

Fixes #18963

Change-Id: Ibce9bf8302110a86c6ab05948569af9ffdfcf4bb
Reviewed-on: https://go-review.googlesource.com/36390
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Reviewed-by: David Chase <drchase@google.com>
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2017-05-05 19:03:05 +00:00
David Crawshaw 27a10f7da7 cmd/link: stop passing unused read_only_relocs
The external darwin linker has been printing:

	ld: warning: -read_only_relocs cannot be used with x86_64

for a long time. Now that it is printed by CL 33301, we may as
well get rid of it.

Fixes #20246

Change-Id: I1147cf1ff197fdfda228a1349f13627bcf9fc72f
Reviewed-on: https://go-review.googlesource.com/42730
Run-TryBot: David Crawshaw <crawshaw@golang.org>
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Reviewed-by: Todd Neal <todd@tneal.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-05 11:35:58 +00:00
Alex Brainman 507f4d5f48 cmd/link: do not read .bss sections in ldpe
For .bss section symbol ldelf does not set P (raw symbol data).
Make ldpe do the same.

Change-Id: Ib3d558456f505ee568d0972465fa9b08b5794a87
Reviewed-on: https://go-review.googlesource.com/42631
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
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2017-05-05 01:00:11 +00:00
Ian Lance Taylor 39c07ce9e5 cmd/link: set ELF CPIC bit in mips64 objects
We already set it for mips32 objects. The native ELF linker warns when
linking PIC objects with non-PIC objects. Our objects are PIC, but we
were not marking them as such.

Fixes #20243.

Change-Id: Ifab131200b263e4c72cf81f7b131a65ac02a13a9
Reviewed-on: https://go-review.googlesource.com/42710
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2017-05-04 20:35:56 +00:00
Shenghou Ma 4d7a5edb7e cmd/link/internal/ld: always show output from external linker
Fixes #17935.

Change-Id: I49b0f6cee29ea76ed62b8faa5d6d1f51be41bf84
Reviewed-on: https://go-review.googlesource.com/33301
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-03 15:01:06 +00:00
Josh Bleecher Snyder 18fb670e5e cmd/internal/obj: fix LSym.Type during compilation, not linking
Prior to this CL, the compiler and assembler
were sloppy about the LSym.Type for LSyms
containing static data.

The linker then fixed this up, converting
Sxxx and SBSS to SDATA, and SNOPTRBSS to SNOPTRDATA
if it noticed that the symbol had associated data.

It is preferable to just get this right in cmd/compile
and cmd/asm, because it removes an unnecessary traversal
of the symbol table from the linker (see #14624).
Do this by touching up the LSym.Type fixes in
LSym.prepwrite and Link.Globl.

I have confirmed by instrumenting the linker
that the now-eliminated code paths were unreached.
And an additional check in the object file writing code
will help preserve that invariant.

There was a case in the Windows linker,
with internal linking and cgo,
where we were generating SNOPTRBSS symbols with data.
For now, convert those at the site at which they occur
into SNOPTRDATA, just like they were.

Does not pass toolstash-check,
but does generate identical linked binaries.

No compiler performance changes.

Change-Id: I77b071ab103685ff8e042cee9abb864385488872
Reviewed-on: https://go-review.googlesource.com/40864
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Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
2017-05-02 00:21:33 +00:00
Michael Hudson-Doyle 164f99e584 Revert "cmd/link: replace SHIDDEN bit in SymKind with a bit of Attribute"
This reverts commit a69222d949.

Reason for revert: broke ppc64le

Change-Id: I57d275177e90f036caf7dbade9669b8121dfa437
Reviewed-on: https://go-review.googlesource.com/42194
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
2017-05-01 00:56:40 +00:00
Michael Hudson-Doyle a69222d949 cmd/link: replace SHIDDEN bit in SymKind with a bit of Attribute
Change-Id: I02dab81393cc9339895f0076df41a652aded5b60
Reviewed-on: https://go-review.googlesource.com/42025
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
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2017-04-30 23:28:47 +00:00
Michael Hudson-Doyle 3bcb481aa3 cmd/link: rename AttrHidden to AttrNotInSymbolTable
I want to move the SHIDDEN type bit into Attribute, but AttrHidden is already
there and means something completely different, so rename it. (I'll give the
SHIDDEN bit a better name when it moves too).

Change-Id: I075403d9542b7626d4c1f6db9094329c4181aad3
Reviewed-on: https://go-review.googlesource.com/42024
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2017-04-30 23:28:29 +00:00
Michael Hudson-Doyle f72534ab6a cmd/link: document the various Attribute values
Change-Id: I11c14111b6c72eab5fc11e9e28cd8b37ad99b401
Reviewed-on: https://go-review.googlesource.com/42019
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
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2017-04-30 23:27:46 +00:00
Michael Hudson-Doyle e29ea14100 cmd/link/internal/ld: unexport ReadOnly and RelROMap
Change-Id: I08e33b92dd8a22e28ec15aa5753904aa8e1c71f5
Reviewed-on: https://go-review.googlesource.com/42031
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-04-28 20:02:50 +00:00
Michael Hudson-Doyle 4aca8b00ff cmd/internal/objabi: shrink SymType down to a uint8
Now that it only takes small values.

Change-Id: I08086d392529d8775b470d65afc2475f8d0e7f4a
Reviewed-on: https://go-review.googlesource.com/42030
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2017-04-28 20:02:20 +00:00
Michael Hudson-Doyle d2a9545178 cmd/internal: remove SymKind values that are only checked for, never set
Change-Id: Id152767c033c12966e9e12ae303b99f38776f919
Reviewed-on: https://go-review.googlesource.com/40987
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
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Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-04-28 20:01:54 +00:00
Michael Hudson-Doyle be2ee2a4b4 cmd/internal/objabi, cmd/link: move linker-only symkind values into linker
Many (most!) of the values of objapi.SymKind are used only in the linker, so
this creates a separate cmd/link/internal/ld.SymKind type, removes most values
from SymKind and maps one to the other when reading object files in the linker.

Two of the remaining objapi.SymKind values are only checked for, never set and
so will never be actually found but I wanted to keep this to the most
mechanical change possible.

Change-Id: I4bbc5aed6713cab3e8de732e6e288eb77be0474c
Reviewed-on: https://go-review.googlesource.com/40985
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2017-04-27 21:56:12 +00:00
Hana Kim b1868cf107 dwarf: add marker for embedded fields in dwarf
Currently, the following two codes generate the identical dwarf info
for type Foo.

prog 1)
type Foo struct {
   Bar
}

prog 2)
type Foo struct {
   Bar Bar
}

This change adds a go-specific attribute DW_AT_go_embedded_field
to annotate each member entry. Its absence or false value indicates
the corresponding member is not an embedded field.

Update #20037

Change-Id: Ibcbd2714f3e4d97c7b523d7398f29ab2301cc897
Reviewed-on: https://go-review.googlesource.com/41873
Reviewed-by: David Chase <drchase@google.com>
2017-04-27 19:57:02 +00:00
Matthew Dempsky 06e5749f01 cmd/link: cleanup after IntSize->PtrSize conversion
Passes toolstash-check -all.

Updates #19954.

Change-Id: Ic162306eed105912491bf1df47e32c32653f824c
Reviewed-on: https://go-review.googlesource.com/41490
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
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2017-04-23 02:07:16 +00:00
Matthew Dempsky c87520c598 cmd: remove IntSize and Widthint
Use PtrSize and Widthptr instead. CL prepared mostly with sed and
uniq.

Passes toolstash-check -all.

Fixes #19954.

Change-Id: I09371bd7128672885cb8bc4e7f534ad56a88d755
Reviewed-on: https://go-review.googlesource.com/40506
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2017-04-22 17:43:43 +00:00
Dave Cheney d728be70f4 cmd/link/internal/ld: remove C style gotos from ldelf
ld.ldelf contained a mixture of normal and C style, goto bad, error
handling. The use of goto requires many variables to be declared well
before their use which inhibited further refactoring to this method.

This CL removes the gotos in this function. Future CLs will address
remainder of the C style function scoped declarations in this function.

Change-Id: Ib9def495209a2f8deb11dcf30ee954bca95390c6
Reviewed-on: https://go-review.googlesource.com/41172
Run-TryBot: Dave Cheney <dave@cheney.net>
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2017-04-20 01:37:08 +00:00
Todd Neal dc444418d9 cmd/internal: remove duplicate pathToPrefix function
goobj.importPathToPrefix is 3x faster than gc.pathToPrefix so rename and
move it to cmd/internal/objabi which is already imported by both goobj and
gc.

Change-Id: I10eda5bce95ef6d5d888818c5c47258c2833ea45
Reviewed-on: https://go-review.googlesource.com/40875
Run-TryBot: Todd Neal <todd@tneal.org>
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2017-04-19 11:47:45 +00:00
Matthew Dempsky 1e3570ac86 cmd/internal/objabi: extract shared functionality from obj
Now only cmd/asm and cmd/compile depend on cmd/internal/obj. Changing
the assembler backends no longer requires reinstalling cmd/link or
cmd/addr2line.

There's also now one canonical definition of the object file format in
cmd/internal/objabi/doc.go, with a warning to update all three
implementations.

objabi is still something of a grab bag of unrelated code (e.g., flag
and environment variable handling probably belong in a separate "tool"
package), but this is still progress.

Fixes #15165.
Fixes #20026.

Change-Id: Ic4b92fac7d0d35438e0d20c9579aad4085c5534c
Reviewed-on: https://go-review.googlesource.com/40972
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2017-04-19 00:00:09 +00:00
Michael Hudson-Doyle 743fe0697d cmd/link: replace Segment's linked list of Sections with a slice
Just noticed this in passing.

Change-Id: I58fa828ef58598209ed4cbe4abc6f9f02ffc4844
Reviewed-on: https://go-review.googlesource.com/40896
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2017-04-18 21:24:32 +00:00
Josh Bleecher Snyder da15fe6870 cmd/internal/obj: rework gclocals handling
The compiler handled gcargs and gclocals LSyms unusually.
It generated placeholder symbols (makefuncdatasym),
filled them in, and then renamed them for content-addressability.
This is an important binary size optimization;
the same locals information occurs over and over.

This CL continues to treat these LSyms unusually,
but in a slightly more explicit way,
and importantly for concurrent compilation,
in a way that does not require concurrent
modification of Ctxt.Hash.

Instead of creating gcargs and gclocals in the usual way,
by creating a types.Sym and then an obj.LSym,
we add them directly to obj.FuncInfo,
initialize them in obj.InitTextSym,
and deduplicate and add them to ctxt.Data at the end.
Then the backend's job is simply to fill them in
and rename them appropriately.

Updates #15756

name       old alloc/op      new alloc/op      delta
Template        38.8MB ± 0%       38.7MB ± 0%  -0.22%  (p=0.016 n=5+5)
Unicode         29.8MB ± 0%       29.8MB ± 0%    ~     (p=0.690 n=5+5)
GoTypes          113MB ± 0%        113MB ± 0%  -0.24%  (p=0.008 n=5+5)
SSA             1.25GB ± 0%       1.24GB ± 0%  -0.39%  (p=0.008 n=5+5)
Flate           25.3MB ± 0%       25.2MB ± 0%  -0.43%  (p=0.008 n=5+5)
GoParser        31.7MB ± 0%       31.7MB ± 0%  -0.22%  (p=0.008 n=5+5)
Reflect         78.2MB ± 0%       77.6MB ± 0%  -0.80%  (p=0.008 n=5+5)
Tar             26.6MB ± 0%       26.3MB ± 0%  -0.85%  (p=0.008 n=5+5)
XML             42.4MB ± 0%       41.9MB ± 0%  -1.04%  (p=0.008 n=5+5)

name       old allocs/op     new allocs/op     delta
Template          378k ± 0%         377k ± 1%    ~     (p=0.151 n=5+5)
Unicode           321k ± 1%         321k ± 0%    ~     (p=0.841 n=5+5)
GoTypes          1.14M ± 0%        1.14M ± 0%  -0.47%  (p=0.016 n=5+5)
SSA              9.71M ± 0%        9.67M ± 0%  -0.33%  (p=0.008 n=5+5)
Flate             233k ± 1%         232k ± 1%    ~     (p=0.151 n=5+5)
GoParser          316k ± 0%         315k ± 0%  -0.49%  (p=0.016 n=5+5)
Reflect           979k ± 0%         972k ± 0%  -0.75%  (p=0.008 n=5+5)
Tar               250k ± 0%         247k ± 1%  -0.92%  (p=0.008 n=5+5)
XML               392k ± 1%         389k ± 0%  -0.67%  (p=0.008 n=5+5)

Change-Id: Idc36186ca9d2f8214b5f7720bbc27b6bb22fdc48
Reviewed-on: https://go-review.googlesource.com/40697
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2017-04-18 02:13:32 +00:00
Michael Hudson-Doyle 533ed967c6 cmd/link: only include the version info and export data in ABI hash
Previously the "ABI hash" for a package (used to determine if a loaded shared
library has the ABI expected by its loader) was the hash of the entire
__.PKGDEF file. But that means it depends on the build ID generated by the go
tool for the package, which means that if a file is added (even a .c or .h
file!) to the package, the ABI changes, perhaps uncessarily.

Fixes #19920

Change-Id: If919481e1a03afb350c8a9c7a0666bb90ee90270
Reviewed-on: https://go-review.googlesource.com/40401
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-04-17 22:02:01 +00:00
David du Colombier 746441f97f cmd/link: skip TestRuntimeTypeDIEs on Plan 9
TestRuntimeTypeDIEs has been added in CL 38350. This
test is failing on Plan 9 because executables don't
have a DWARF symbol table.

Fixes #19944.

Change-Id: I121875bfd5f9f02ed668f8fb0686a0edffa2a99d
Reviewed-on: https://go-review.googlesource.com/40452
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-04-12 18:16:41 +00:00
Alessandro Arzilli 073247f11f cmd/link: export specialized variants of runtime._type to debug_info
The reflect package can be used to create new types at runtime, these
types will have runtime._type entries describing them but no entry in
debug_info (obviously).

A debugger that wanted to print the value of variables with such types
will have to read the runtime._type directly, however the
"specializations" of runtime._type (runtime.slicetype, runtime.maptype,
etc) are not exported to debug_info, besides runtime.interfacetype.

All those types (i.e. runtime.slicetype, runtime.maptype, etc) should
be exported to debug_info so that debuggers don't have to hard-code
their description.

Fixes #19602

Change-Id: I086d523a4421a4ed964e16bc3c2274319a98b45b
Reviewed-on: https://go-review.googlesource.com/38350
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
2017-04-12 13:25:45 +00:00
Joel Sing 9417c022c6 cmd/link,runtime/cgo: enable PT_TLS generation on OpenBSD
OpenBSD 6.0 and later have support for PT_TLS in ld.so(1). Now that OpenBSD
6.1 has been released, OpenBSD 5.9 is no longer officially supported and Go
can start generating PT_TLS for OpenBSD cgo binaries. This also allows us
to remove the workarounds in the OpenBSD cgo runtime.

This change also removes the environ and progname exports - these are now
provided directly by ld.so(1) itself.

Fixes #19932

Change-Id: I42e75ef9feb5dcd4696add5233497e3cbc48ad52
Reviewed-on: https://go-review.googlesource.com/40331
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-04-11 16:33:16 +00:00
Josh Bleecher Snyder 3cf1ce40bd Revert "cmd/compile: output DWARF lexical blocks for local variables"
This reverts commit c8b889cc48.

Reason for revert: broke noopt build, compiler performance regression, new Curfn uses

Let's fix those and then try this again.

Change-Id: Icc3cad1365d04cac8fd09da9dbb0bbf55c13ef44
Reviewed-on: https://go-review.googlesource.com/39991
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-04-07 19:52:26 +00:00
Alessandro Arzilli c8b889cc48 cmd/compile: output DWARF lexical blocks for local variables
Change compiler and linker to emit DWARF lexical blocks in debug_info.
Version of debug_info is updated from DWARF v.2 to DWARF v.3 since version 2
does not allow lexical blocks with discontinuous ranges.

Second attempt at https://go-review.googlesource.com/#/c/29591/

Remaining open problems:
- scope information is removed from inlined functions
- variables in debug_info do not have DW_AT_start_scope attributes so a
variable will shadow other variables with the same name as soon as its
containing scope begins, before its declaration.

Updates golang/go#12899, golang/go#6913

Change-Id: I0e260a45b564d14a87b88974eb16c5387cb410a5
Reviewed-on: https://go-review.googlesource.com/36879
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-04-07 18:15:06 +00:00
Cherry Zhang a1cedf0842 cmd/link: canonicalize the "package" of dupok text symbols
Dupok symbols may be defined in multiple packages. Its associated
package is chosen sort of arbitrarily (the first containing package
that the linker loads). Canonicalize its package to the package
with which it will be laid down in text, which is the first package
in dependency order that defines the symbol. So later passes (for
example, trampoline insertion pass) know that the dupok symbol
is laid down along with the package.

Fixes #19764.

Change-Id: I7cbc7474ff3016d5069c8b7be04af934abab8bc3
Reviewed-on: https://go-review.googlesource.com/39150
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: David Chase <drchase@google.com>
2017-04-02 03:25:02 +00:00
Alex Brainman 361af94d5d cmd/internal/obj, cmd/link: remove Hwindowsgui everywhere
Hwindowsgui has the same meaning as Hwindows - build PE
executable. So use Hwindows everywhere.

Change-Id: I2cae5777f17c7bc3a043dfcd014c1620cc35fc20
Reviewed-on: https://go-review.googlesource.com/38761
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-03-30 22:51:43 +00:00
Alex Brainman 4e3a1e409a cmd/link/internal/ld: introduce and use windowsgui variable
cmd/link -H flag is stored in variable of type
cmd/internal/obj.HeadType. The HeadType type from cmd/internal/obj
accepts Hwindows and Hwindowsgui values, but these values have
same meaning - build PE executable, except for 2 places in
cmd/link/internal/ld package.

This CL introduces code to store cmd/link "windowsgui" -H flag
in cmd/link/internal/ld, so cmd/internal/obj.Hwindowsgui can be
removed in the next CL.

This CL also includes 2 changes to code where distinction
between Hwindows and Hwindowsgui is important.

Change-Id: Ie5ee1f374e50c834652a037f2770118d56c21a2a
Reviewed-on: https://go-review.googlesource.com/38760
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-03-30 22:51:19 +00:00
Josh Bleecher Snyder 94c62efe9c cmd/link: skip TestDWARF when cgo is disabled
While we're here, fix a Skip/Skipf error I noticed.

Fixes #19796.

Change-Id: I59b1f5b5ea727fc314acfee8445b3de0b5af1e46
Reviewed-on: https://go-review.googlesource.com/38992
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-03-30 22:32:33 +00:00
David du Colombier ed6f2978a2 cmd/link: skip TestDWARF on Plan 9
TestDWARF has been added in CL 38855. This test is
failing on Plan 9 because executables don't have
a DWARF symbol table.

Fixes #19793.

Change-Id: I7fc547a7c877b58cc4ff6b4eb5b14852e8b4668b
Reviewed-on: https://go-review.googlesource.com/38931
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-03-30 20:24:19 +00:00
Russ Cox 18e77673d8 cmd/link: emit a mach-o dwarf segment that dsymutil will accept
Right now, at least with Xcode 8.3, we invoke dsymutil and dutifully
copy what it produces back into the binary, but it has actually dropped
all the DWARF information that we wanted, because it didn't like
the look of go.o.

Make it like the look of go.o.

DWARF is tested in other ways, but typically indirectly and not for cgo programs.
Add a direct test, and one that exercises cgo.
This detects missing dwarf information in cgo-using binaries on macOS,
at least with Xcode 8.3, and possibly earlier versions as well.

Fixes #19772.

Change-Id: I0082e52c0bc8fc4e289770ec3dc02f39fd61e743
Reviewed-on: https://go-review.googlesource.com/38855
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-03-30 17:31:50 +00:00
Russ Cox b28f2f7399 cmd/link: make mach-o dwarf segment properly aligned
Without this, the load fails during kernel exec, which results in the
mysterious and completely uninformative "Killed: 9" error.

It appears that the stars (or at least the inputs) were properly aligned
with earlier versions of Xcode so that this happened accidentally.
Make it happen on purpose.

Gregory Man bisected the breakage to this change in LLVM,
which fits the theory nicely:
https://github.com/llvm-mirror/llvm/commit/9a41e59c

Fixes #19734.

Change-Id: Ice67a09af2de29d3c0d5e3fcde6a769580897c95
Reviewed-on: https://go-review.googlesource.com/38854
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-03-30 12:29:18 +00:00
Russ Cox 23dc3633ca cmd/link: disable mach-o dwarf munging with -w (in addition to -s)
Might as well provide a way around the mach-o munging
that doesn't require stripping all symbols.
After all, -w does mean no DWARF.

For #11887, #19734, and anyone else that needs to disable
this code path without losing the symbol table.

Change-Id: I254b7539f97fb9211fa90f446264b383e7f3980f
Reviewed-on: https://go-review.googlesource.com/38853
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-03-30 12:28:11 +00:00
Russ Cox 371c83b594 cmd/link: do not pass -s through to host linker on macOS
This keeps the host linker from printing
ld: warning: option -s is obsolete and being ignored

Fixes #19775.

Change-Id: I18dd4e4b3f59cbf35dad770fd65e6baea5a7347f
Reviewed-on: https://go-review.googlesource.com/38851
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-03-30 02:45:45 +00:00
Cherry Zhang 15b37655bc cmd/link: on PPC64, put plt stubs at beginning of Textp
Put call stubs at the beginning (instead of the end). So the
trampoline pass knows the addresses of the stubs, and it can
insert trampolines when necessary.

Fixes #19425.

Change-Id: I1e06529ef837a6130df58917315610d45a6819ca
Reviewed-on: https://go-review.googlesource.com/38131
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
2017-03-15 16:19:27 +00:00
Matthew Dempsky d343478295 cmd/link: eliminate markextra
This appears to be leftover from when instruction selection happened
in the linker. Many of the morestackX functions listed don't even
exist anymore.

Now that we select instructions within the compiler and assembler,
normal deadcode elimination mechanisms should suffice for these
symbols.

Change-Id: I2cb1e435101392e7c983957c4acfbbcc87a5ca7d
Reviewed-on: https://go-review.googlesource.com/38077
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-03-12 11:05:10 +00:00
Alex Brainman d3f5e36917 cmd/link: use IMAGE_SYM_CLASS_STATIC for local symbols
Sometimes asm code in 2 different packages name its global
symbols with the same name. When these symbols are passed
to gcc, it refuses to link them thinking they are duplicate.
Mark these symbols with IMAGE_SYM_CLASS_STATIC.

Fixes #19198.

Change-Id: Ia5f59ede47354a2b48ce60b7d406c9f097ff2000
Reviewed-on: https://go-review.googlesource.com/37810
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-03-07 03:26:47 +00:00
Matthew Dempsky 7c84dc79fd cmd/internal/obj, cmd/link: bump magic string to go19ld
golang.org/cl/37231 changed the object file format, but forgot to bump
the version string.

Change-Id: I8351ec8ed55e65479006e7c0df20254d0e31015f
Reviewed-on: https://go-review.googlesource.com/37798
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-03-06 19:13:57 +00:00
Josh Bleecher Snyder 57e038615d cmd/internal/src: cache prefixed filenames
CL 37234 introduced string concatenation into some hot code. 
This CL does that work earlier and caches the result.

Updates #19386

Performance impact vs master:

name       old time/op      new time/op      delta
Template        223ms ± 5%       216ms ± 5%   -2.98%  (p=0.001 n=20+20)
Unicode        98.7ms ± 4%      99.0ms ± 4%     ~     (p=0.749 n=20+19)
GoTypes         631ms ± 4%       626ms ± 4%     ~     (p=0.253 n=20+20)
Compiler        2.91s ± 1%       2.87s ± 3%   -1.11%  (p=0.005 n=18+20)
SSA             4.48s ± 2%       4.36s ± 2%   -2.77%  (p=0.000 n=20+20)
Flate           130ms ± 2%       129ms ± 6%     ~     (p=0.428 n=19+20)
GoParser        160ms ± 4%       157ms ± 3%   -1.62%  (p=0.005 n=20+18)
Reflect         395ms ± 2%       394ms ± 4%     ~     (p=0.445 n=20+20)
Tar             120ms ± 5%       118ms ± 6%     ~     (p=0.101 n=19+20)
XML             224ms ± 3%       223ms ± 3%     ~     (p=0.544 n=19+19)

name       old user-ns/op   new user-ns/op   delta
Template   291user-ms ± 5%  265user-ms ± 5%   -9.02%  (p=0.000 n=20+19)
Unicode    140user-ms ± 3%  139user-ms ± 8%     ~     (p=0.904 n=20+20)
GoTypes    844user-ms ± 3%  849user-ms ± 3%     ~     (p=0.251 n=20+18)
Compiler   4.06user-s ± 5%  3.98user-s ± 2%     ~     (p=0.056 n=20+20)
SSA        6.89user-s ± 5%  6.50user-s ± 3%   -5.61%  (p=0.000 n=20+20)
Flate      164user-ms ± 5%  163user-ms ± 4%     ~     (p=0.365 n=20+19)
GoParser   206user-ms ± 6%  204user-ms ± 4%     ~     (p=0.534 n=20+18)
Reflect    501user-ms ± 4%  505user-ms ± 5%     ~     (p=0.383 n=20+20)
Tar        151user-ms ± 3%  152user-ms ± 7%     ~     (p=0.798 n=17+20)
XML        283user-ms ± 7%  280user-ms ± 5%     ~     (p=0.301 n=20+20)

name       old alloc/op     new alloc/op     delta
Template       42.5MB ± 0%      40.2MB ± 0%   -5.59%  (p=0.000 n=20+20)
Unicode        31.7MB ± 0%      31.0MB ± 0%   -2.19%  (p=0.000 n=20+18)
GoTypes         124MB ± 0%       117MB ± 0%   -5.90%  (p=0.000 n=20+20)
Compiler        533MB ± 0%       490MB ± 0%   -8.07%  (p=0.000 n=20+20)
SSA             989MB ± 0%       893MB ± 0%   -9.74%  (p=0.000 n=20+20)
Flate          27.8MB ± 0%      26.1MB ± 0%   -5.92%  (p=0.000 n=20+20)
GoParser       34.3MB ± 0%      32.1MB ± 0%   -6.43%  (p=0.000 n=19+20)
Reflect        84.6MB ± 0%      81.4MB ± 0%   -3.84%  (p=0.000 n=20+20)
Tar            28.8MB ± 0%      27.7MB ± 0%   -3.89%  (p=0.000 n=20+20)
XML            47.2MB ± 0%      44.2MB ± 0%   -6.45%  (p=0.000 n=20+19)

name       old allocs/op    new allocs/op    delta
Template         420k ± 1%        381k ± 1%   -9.35%  (p=0.000 n=20+20)
Unicode          338k ± 1%        324k ± 1%   -4.29%  (p=0.000 n=20+19)
GoTypes         1.28M ± 0%       1.15M ± 0%  -10.30%  (p=0.000 n=20+20)
Compiler        5.06M ± 0%       4.41M ± 0%  -12.92%  (p=0.000 n=20+20)
SSA             9.14M ± 0%       7.91M ± 0%  -13.46%  (p=0.000 n=19+20)
Flate            267k ± 0%        241k ± 1%   -9.53%  (p=0.000 n=20+20)
GoParser         347k ± 1%        312k ± 0%  -10.15%  (p=0.000 n=19+20)
Reflect         1.07M ± 0%       1.00M ± 0%   -6.86%  (p=0.000 n=20+20)
Tar              274k ± 1%        256k ± 1%   -6.73%  (p=0.000 n=20+20)
XML              448k ± 0%        398k ± 0%  -11.17%  (p=0.000 n=20+18)


Performance impact when applied together with CL 37234
atop CL 37234's parent commit (i.e. as if it were
a part of CL 37234), to show that this commit
makes CL 37234 completely performance-neutral:

name       old time/op      new time/op      delta
Template        222ms ±14%       222ms ±14%    ~     (p=1.000 n=14+15)
Unicode         104ms ±18%       106ms ±18%    ~     (p=0.650 n=13+14)
GoTypes         653ms ± 7%       638ms ± 5%    ~     (p=0.145 n=14+12)
Compiler        3.10s ± 1%       3.13s ±10%    ~     (p=1.000 n=2+2)
SSA             4.73s ±11%       4.68s ±11%    ~     (p=0.567 n=15+15)
Flate           136ms ± 4%       133ms ± 7%    ~     (p=0.231 n=12+14)
GoParser        163ms ±11%       169ms ±10%    ~     (p=0.352 n=14+14)
Reflect         415ms ±15%       423ms ±20%    ~     (p=0.715 n=15+14)
Tar             133ms ±17%       130ms ±23%    ~     (p=0.252 n=14+15)
XML             236ms ±16%       235ms ±14%    ~     (p=0.874 n=14+14)

name       old user-ns/op   new user-ns/op   delta
Template   271user-ms ±10%  271user-ms ±10%    ~     (p=0.780 n=14+15)
Unicode    143user-ms ± 5%  146user-ms ±11%    ~     (p=0.432 n=12+14)
GoTypes    864user-ms ± 5%  866user-ms ± 9%    ~     (p=0.905 n=14+13)
Compiler   4.17user-s ± 1%  4.26user-s ± 7%    ~     (p=1.000 n=2+2)
SSA        6.79user-s ± 8%  6.79user-s ± 6%    ~     (p=0.902 n=15+15)
Flate      169user-ms ± 8%  164user-ms ± 5%  -3.13%  (p=0.014 n=14+14)
GoParser   212user-ms ± 7%  217user-ms ±22%    ~     (p=1.000 n=13+15)
Reflect    521user-ms ± 7%  533user-ms ±15%    ~     (p=0.511 n=14+14)
Tar        165user-ms ±17%  161user-ms ±15%    ~     (p=0.345 n=15+15)
XML        294user-ms ±11%  292user-ms ±10%    ~     (p=0.839 n=14+14)

name       old alloc/op     new alloc/op     delta
Template       39.9MB ± 0%      39.9MB ± 0%    ~     (p=0.621 n=15+14)
Unicode        31.0MB ± 0%      31.0MB ± 0%    ~     (p=0.098 n=13+15)
GoTypes         117MB ± 0%       117MB ± 0%    ~     (p=0.775 n=15+15)
Compiler        488MB ± 0%       488MB ± 0%    ~     (p=0.333 n=2+2)
SSA             892MB ± 0%       892MB ± 0%  +0.03%  (p=0.000 n=15+15)
Flate          26.1MB ± 0%      26.1MB ± 0%    ~     (p=0.098 n=15+15)
GoParser       31.8MB ± 0%      31.8MB ± 0%    ~     (p=0.525 n=15+13)
Reflect        81.2MB ± 0%      81.2MB ± 0%  +0.06%  (p=0.001 n=12+14)
Tar            27.5MB ± 0%      27.5MB ± 0%    ~     (p=0.595 n=15+15)
XML            44.1MB ± 0%      44.1MB ± 0%    ~     (p=0.486 n=15+15)

name       old allocs/op    new allocs/op    delta
Template         378k ± 1%        378k ± 0%    ~     (p=0.949 n=15+14)
Unicode          324k ± 0%        324k ± 1%    ~     (p=0.057 n=14+15)
GoTypes         1.15M ± 0%       1.15M ± 0%    ~     (p=0.461 n=15+15)
Compiler        4.39M ± 0%       4.39M ± 0%    ~     (p=0.333 n=2+2)
SSA             7.90M ± 0%       7.90M ± 0%  +0.06%  (p=0.008 n=15+15)
Flate            240k ± 1%        241k ± 0%    ~     (p=0.233 n=15+15)
GoParser         309k ± 1%        309k ± 0%    ~     (p=0.867 n=15+12)
Reflect         1.00M ± 0%       1.00M ± 0%    ~     (p=0.139 n=12+15)
Tar              254k ± 1%        253k ± 1%    ~     (p=0.345 n=15+15)
XML              398k ± 0%        397k ± 1%    ~     (p=0.267 n=15+15)


Change-Id: Ic999a0f456a371c99eebba0f9747263a13836e33
Reviewed-on: https://go-review.googlesource.com/37766
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-03-04 18:19:06 +00:00
David Lazar 301149b9e4 cmd/internal/obj: avoid duplicate file name symbols
The meaning of Version=1 was overloaded: it was reserved for file name
symbols (to avoid conflicts with non-file name symbols), but was also
used to mean "give me a fresh version number for this symbol."

With the new inlining tree, the same file name symbol can appear in
multiple entries, but each one would become a distinct symbol with its
own version number.

Now, we avoid duplicating symbols by using Version=0 for file name
symbols and we avoid conflicts with other symbols by prefixing the
symbol name with "gofile..".

Change-Id: I8d0374053b8cdb6a9ca7fb71871b69b4dd369a9c
Reviewed-on: https://go-review.googlesource.com/37234
Run-TryBot: David Lazar <lazard@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
2017-03-03 21:29:36 +00:00
David Lazar 699175a11a cmd/compile,link: generate PC-value tables with inlining information
In order to generate accurate tracebacks, the runtime needs to know the
inlined call stack for a given PC. This creates two tables per function
for this purpose. The first table is the inlining tree (stored in the
function's funcdata), which has a node containing the file, line, and
function name for every inlined call. The second table is a PC-value
table that maps each PC to a node in the inlining tree (or -1 if the PC
is not the result of inlining).

To give the appearance that inlining hasn't happened, the runtime also
needs the original source position information of inlined AST nodes.
Previously the compiler plastered over the line numbers of inlined AST
nodes with the line number of the call. This meant that the PC-line
table mapped each PC to line number of the outermost call in its inlined
call stack, with no way to access the innermost line number.

Now the compiler retains line numbers of inlined AST nodes and writes
the innermost source position information to the PC-line and PC-file
tables. Some tools and tests expect to see outermost line numbers, so we
provide the OutermostLine function for displaying line info.

To keep track of the inlined call stack for an AST node, we extend the
src.PosBase type with an index into a global inlining tree. Every time
the compiler inlines a call, it creates a node in the global inlining
tree for the call, and writes its index to the PosBase of every inlined
AST node. The parent of this node is the inlining tree index of the
call. -1 signifies no parent.

For each function, the compiler creates a local inlining tree and a
PC-value table mapping each PC to an index in the local tree.  These are
written to an object file, which is read by the linker.  The linker
re-encodes these tables compactly by deduplicating function names and
file names.

This change increases the size of binaries by 4-5%. For example, this is
how the go1 benchmark binary is impacted by this change:

section             old bytes   new bytes   delta
.text               3.49M ± 0%  3.49M ± 0%   +0.06%
.rodata             1.12M ± 0%  1.21M ± 0%   +8.21%
.gopclntab          1.50M ± 0%  1.68M ± 0%  +11.89%
.debug_line          338k ± 0%   435k ± 0%  +28.78%
Total               9.21M ± 0%  9.58M ± 0%   +4.01%

Updates #19348.

Change-Id: Ic4f180c3b516018138236b0c35e0218270d957d3
Reviewed-on: https://go-review.googlesource.com/37231
Run-TryBot: David Lazar <lazard@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2017-03-03 21:29:30 +00:00
Alex Brainman 29f061960d cmd/link: write dwarf sections
Also stop skipping TestExternalLinkerDWARF and
TestDefaultLinkerDWARF.

Fixes #10776.

Change-Id: Ia596a684132e3cdee59ce5539293eedc1752fe5a
Reviewed-on: https://go-review.googlesource.com/36983
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-03-01 04:51:03 +00:00
Alex Brainman aada49038c cmd/link: write dwarf relocations
For #10776.

Change-Id: I11dd441d8e5d6316889ffa8418df8b58c57c677d
Reviewed-on: https://go-review.googlesource.com/36982
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-03-01 04:49:29 +00:00
Bill O'Farrell a6b480bc07 cmd/go: implement -buildmode=plugin for s390x
Simple change to allow plugins for linux on s390x

Change-Id: I5c262ab81aac10d1dcb03381a48e5b9694b7a87a
Reviewed-on: https://go-review.googlesource.com/37451
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-02-25 14:31:10 +00:00
Alex Brainman b32170abdf cmd/link: simplify peemitreloc
No functional changes.

For #10776.

Change-Id: If9a5ef832af116c5802b06a38e0c050d7363f2d5
Reviewed-on: https://go-review.googlesource.com/36981
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-02-21 06:11:39 +00:00
Alex Brainman d0a978f5b5 cmd/link: reorder pe sections
dwarf writing code assumes that dwarf sections follow
.data and .bss, not .ctors. Make pe section writing code
match that assumption.

For #10776.

Change-Id: I128c3ad125f7d0db19e922f165704a054b2af7ba
Reviewed-on: https://go-review.googlesource.com/36980
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-02-21 06:11:17 +00:00
Alex Brainman 6db4d92e4c cmd/link: do not add __image_base__ and _image_base__ if external linker
The symbols get in a way when using external linker. They are
not associated with a section. And linker fails when
generating relocations for them.

__image_base__ and _image_base__ have been added long time ago.
I do not think they are needed anymore. If I delete them, all
tests still PASS. I tried going back to the commit that added
them to see if I can reproduce original error, but I cannot
build it. I don't have hg version of go repo, and my gcc is
complaining about cc source code.

I wasted too much time with this, so I decided to leave them only
for internal linker. That is what they were originally added for.

For #10776.

Change-Id: Ibb72b04f3864947c782f964a7badc69f4b074e25
Reviewed-on: https://go-review.googlesource.com/36979
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-02-21 06:10:51 +00:00
Alex Brainman b660a4b04d cmd/link: add all pe section names to pe symbol table
dwarf relocations refer to dwarf section symbols, so dwarf
section symbols must be present in pe symbol table before we
write dwarf relocations.

.ctors pe section already refer to .text symbol.

Write all pe section name symbols into symbol table, so we
can use them whenever we need them.

This CL also simplified some code.

For #10776.

Change-Id: I9b8c680ea75904af90c797a06bbb1f4df19e34b6
Reviewed-on: https://go-review.googlesource.com/36978
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-21 05:52:04 +00:00
Alex Brainman e9abf1a716 cmd/link: introduce shNames
Introduce a slice that keeps long pe section names as we add them.
It will be used later to output pe symbol table and dwarf relocations.

For #10776.

Change-Id: I02f808a456393659db2354031baf1d4f9e0b2d61
Reviewed-on: https://go-review.googlesource.com/36977
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-21 05:41:43 +00:00
Alex Brainman a7e2556255 cmd/link: set VirtualAddress to 0 for external linker
This is what gcc does when it generates object files.
And pecoff.doc says: "for simplicity, compilers should
 set this to zero". It is easier to count everything,
when it starts from 0. Make go linker do the same.

For #10776.

Change-Id: Iffa4b3ad86160624ed34adf1c6ba13feba34c658
Reviewed-on: https://go-review.googlesource.com/36976
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-21 01:05:55 +00:00
Alex Brainman 0ad247c6f0 cmd/link: delay calculating pe file parameters after Linkmode is set
For #10776.

Change-Id: Id64a7e35c7cdcd9be16cbe3358402fa379090e36
Reviewed-on: https://go-review.googlesource.com/36975
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-16 04:35:36 +00:00
Alex Brainman e31144f128 cmd/link: set pe section and file alignment to 0 during external linking
This is what gcc does when it generates object files.
And it is easier to count everything, when it starts from 0.
Make go linker do the same.

gcc also does not output IMAGE_OPTIONAL_HEADER or
PE64_IMAGE_OPTIONAL_HEADER for object files.
Perhaps we should do the same, but not in this CL.

For #10776.

Change-Id: I9789c337648623b6cfaa7d18d1ac9cef32e180dc
Reviewed-on: https://go-review.googlesource.com/36974
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-02-16 04:33:17 +00:00
Daniel Martí 99df7c9caa cmd/link, crypto/tls: don't use append loops
Change-Id: Ib47e295e8646b769c30fd81e5c7f20f964df163e
Reviewed-on: https://go-review.googlesource.com/36335
Reviewed-by: Filippo Valsorda <hi@filippo.io>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-07 16:42:32 +00:00
David Crawshaw ab067cde34 cmd/link: use external linking for PIE by default
Now `go test -buildmode=pie std -short` passes on linux/amd64.

Updates #18968

Change-Id: Ide21877713e00edc64c1700c950016d6bff8de0e
Reviewed-on: https://go-review.googlesource.com/36417
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-06 23:04:46 +00:00
Alex Brainman c7a7c5a9b4 cmd/link: do not prefix external symbols with underscore on windows/386/cgo
CL 18057 added underscore to most external pe symbols
on windows/386/cgo. The CL changed runtime.epclntab and
runtime.pclntab pe symbols into _runtime.pclntab and
_runtime.epclntab, and now cmd/nm cannot find them.
Revert correspondent CL 18057 changes, because most pe
symbols do not need underscore prefix.

This CL also removes code that added obj.SHOSTOBJ symbols
explicitly, because each of those was also added via
genasmsym call. These created duplicate pe symbols (like
_GetProcAddress@8 and __GetProcAddress@8), and external
linker would complain.

This CL adds new test in cmd/nm to verify go programs
built with cgo.

Fixes #18416

Change-Id: I68b1be8fb631d95ec69bd485c77c79604fb23f26
Reviewed-on: https://go-review.googlesource.com/35076
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-04 05:56:45 +00:00
Alex Brainman 99e1e4f657 cmd/link: assume that runtime.epclntab lives in .text section
Sometimes STEXT symbols point to the first byte of .data
section, instead of the end of .text section. But, while writing
pe symbol table, we should treat them as if they belong to the
.text section. Change pe symbol table records for these symbols.

Fixes #14710

Change-Id: I1356e61aa8fa37d590d7b1677b2bac214ad0ba4e
Reviewed-on: https://go-review.googlesource.com/35272
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2017-02-02 04:05:11 +00:00
Russ Cox c47df7ae17 all: merge dev.typealias into master
For #18130.

f8b4123613 [dev.typealias] spec: use term 'embedded field' rather than 'anonymous field'
9ecc3ee252 [dev.typealias] cmd/compile: avoid false positive cycles from type aliases
49b7af8a30 [dev.typealias] reflect: add test for type aliases
9bbb07ddec [dev.typealias] cmd/compile, reflect: fix struct field names for embedded byte, rune
43c7094386 [dev.typealias] reflect: fix StructOf use of StructField to match StructField docs
9657e0b077 [dev.typealias] cmd/doc: update for type alias
de2e5459ae [dev.typealias] cmd/compile: declare methods after resolving receiver type
9259f3073a [dev.typealias] test: match gccgo error messages on alias2.go
5d92916770 [dev.typealias] cmd/compile: change Func.Shortname to *Sym
a7c884efc1 [dev.typealias] go/internal/gccgoimporter: support for type aliases
5802cfd900 [dev.typealias] cmd/compile: export/import test cases for type aliases
d7cabd40dd [dev.typealias] go/types: clarified doc string
cc2dcce3d7 [dev.typealias] cmd/compile: a few better comments related to alias types
5c160b28ba [dev.typealias] cmd/compile: improved error message for cyles involving type aliases
b2386dffa1 [dev.typealias] cmd/compile: type-check type alias declarations
ac8421f9a5 [dev.typealias] cmd/compile: various minor cleanups
f011e0c6c3 [dev.typealias] cmd/compile, go/types, go/importer: various alias related fixes
49de5f0351 [dev.typealias] cmd/compile, go/importer: define export format and implement importing of type aliases
5ceec42dc0 [dev.typealias] go/types: export TypeName.IsAlias so clients can use it
aa1f0681bc [dev.typealias] go/types: improved Object printing
c80748e389 [dev.typealias] go/types: remove some more vestiges of prior alias implementation
80d8b69e95 [dev.typealias] go/types: implement type aliases
a917097b5e [dev.typealias] go/build: add go1.9 build tag
3e11940437 [dev.typealias] cmd/compile: recognize type aliases but complain for now (not yet supported)
e0a05c274a [dev.typealias] cmd/gofmt: added test cases for alias type declarations
2e5116bd99 [dev.typealias] go/ast, go/parser, go/printer, go/types: initial type alias support

Change-Id: Ia65f2e011fd7195f18e1dce67d4d49b80a261203
2017-01-31 13:01:31 -05:00
Russ Cox 9bbb07ddec [dev.typealias] cmd/compile, reflect: fix struct field names for embedded byte, rune
Will also fix type aliases.

Fixes #17766.
For #18130.

Change-Id: I9e1584d47128782152e06abd0a30ef423d5c30d2
Reviewed-on: https://go-review.googlesource.com/35732
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-01-25 18:57:20 +00:00
Ian Lance Taylor aad06da2b9 cmd/link: mark DWARF function symbols as reachable
Otherwise we don't emit any required ELF relocations when doing an
external link, because elfrelocsect skips unreachable symbols.

Fixes #18745.

Change-Id: Ia3583c41bb6c5ebb7579abd26ed8689370311cd6
Reviewed-on: https://go-review.googlesource.com/35590
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2017-01-24 03:37:56 +00:00
David Crawshaw 9cf06ed6cd cmd/link: only exclude C-only symbols on darwin
C-only symbols are excluded from pclntab because of a quirk of darwin,
where functions are referred to by an exported symbol so dynamic
relocations de-duplicate to the host binary module and break unwinding.

This doesn't happen on ELF systems because the linker always refers to
unexported module-local symbols, so we don't need this condition.
And the current logic for excluding some functions breaks the module
verification code in moduledataverify1. So disable this for plugins
on linux.

(In 1.9, it will probably be necessary to introduce a module-local
symbol reference system on darwin to fix a different bug, so all of
this onlycsymbol code made be short-lived.)

With this CL, the tests in CL 35116 pass.

Change-Id: I517d7ca4427241fa0a91276c462827efb9383be9
Reviewed-on: https://go-review.googlesource.com/35190
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-01-12 23:48:11 +00:00
Russ Cox f64b7d301d cmd/link: use 64k segment alignment on linux/arm
Otherwise 64k pages don't map correctly.

Fixes #18408.

Change-Id: I85f56682531566d1ff5c655640cd58509514aee8
Reviewed-on: https://go-review.googlesource.com/34629
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2017-01-04 18:32:38 +00:00
Ian Lance Taylor f78cd569f5 cmd/link: don't suggest using nm to find -X name
It doesn't work if the package name includes a '.' or a non-ASCII
character (or '%', '"', or a control character).  See #16710 and CL 31970.

Update #18246.

Change-Id: I1487f462a3dc7b0016fce3aa1ea6239b226e6e39
Reviewed-on: https://go-review.googlesource.com/34791
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-01-02 17:56:17 +00:00
Austin Clements 61db2e4efa runtime: cross-reference _func type better
It takes me several minutes every time I want to find where the linker
writes out the _func structures. Add some comments to make this
easier.

Change-Id: Ic75ce2786ca4b25726babe3c4fe9cd30c85c34e2
Reviewed-on: https://go-review.googlesource.com/34390
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-12-16 17:03:25 +00:00
Vladimir Stefanovic a3b670e333 cmd/link: add external linking support for GOARCH=mips{,le}
Fixes #17792.

Change-Id: If4f24455eec0edb3b221aef6777a681f6c768866
Reviewed-on: https://go-review.googlesource.com/34313
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-12-14 23:51:55 +00:00
David Crawshaw 96414ca39f cmd/link: do not export plugin C symbols
Explicitly filter any C-only cgo functions out of pclntable,
which allows them to be duplicated with the host binary.

Updates #18190.

Change-Id: I50d8706777a6133b3e95f696bc0bc586b84faa9e
Reviewed-on: https://go-review.googlesource.com/34199
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-12-14 19:36:20 +00:00
Ian Lance Taylor 73151700b4 cmd/link: improve -X doc wording
Change-Id: I9329738ec5dd6c12f72eea7de413d66617b7b5c2
Reviewed-on: https://go-review.googlesource.com/34373
Reviewed-by: Rob Pike <r@golang.org>
2016-12-14 01:43:58 +00:00
Ian Lance Taylor 4284edb999 cmd/link: explain how to find the name to use for -X
Doc change only.

Fixes #18246.

Change-Id: I2c7b181bcec81e124d30702f6fac5aa43bb57c04
Reviewed-on: https://go-review.googlesource.com/34230
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-12-14 00:11:37 +00:00
David Crawshaw ab5a2173f9 cmd/link: limit darwin dynlink symbol exports
The pclntable contains pointers to functions. If the function symbol
is exported in a plugin, and there is a matching symbol in the host
binary, then the pclntable of a plugin ends up pointing at the
function in the host module.

This doesn't work because the traceback code expects the pointer to
be in the same module space as the PC value.

So don't export functions that might overlap with the host binary.
This way the pointer stays in its module.

Updates #18190

Change-Id: Ifb77605b35fb0a1e7edeecfd22b1e335ed4bb392
Reviewed-on: https://go-review.googlesource.com/34196
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-12-10 17:03:45 +00:00
Brad Fitzpatrick 4c4201f0e2 all: make spelling consistent
Fixes #17938

Change-Id: Iad12155f4976846bd4a9a53869f89e40e5b3deb3
Reviewed-on: https://go-review.googlesource.com/34147
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
2016-12-08 23:22:37 +00:00
Michael Hudson-Doyle 67b2927990 cmd/link: do not mark go.plugin.tabs as reachable in non-plugins
Fixes #18250

Change-Id: I4f61591356ddb4a906c206ad8456d1839daf7b91
Reviewed-on: https://go-review.googlesource.com/34170
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-12-08 20:01:23 +00:00
Lynn Boger 6623988eb7 cmd/link: fix sym sect when splitting text on ppc64le
While processing a symbol for a function, if it is determined
that a function would make the text section too large then
a new text section is created and the address of the function
is in the new text section.  But the symbol for the function
is marked as being in the previous text section, causing
incorrect codegen for the function and leading to a segv if
that function is called.  This adds code to set the sym.Sect
field to the new section if a new one is created.  Note that
this problem only happens at the point where a new section is
created.

Fixes #18218

Change-Id: Ic21ae11368d9d88ff6d5d3977f9ea72fe6477ed1
Reviewed-on: https://go-review.googlesource.com/34069
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-12-07 18:19:02 +00:00
David Crawshaw 348a7c5397 cmd/link: hash packages after loading all symbols
Conditioning on the plugin.Open symbol existing before loading all
symbols means sometimes some packages don't have a hash value.

Fixes #17928

Change-Id: I2722449aa58eca08a25117d3ce976f11f805b5ac
Reviewed-on: https://go-review.googlesource.com/33925
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-12-06 14:07:40 +00:00
Ian Lance Taylor 130ad87ab7 cmd/link: don't overalign ELF reloc sections
Internal linking on an ELF system creates two reloc sections, which
must be adjacent. The default is to base section alignment on the
section size, but doing that for ELF reloc sections can introduce a
gap. Set the reloc section alignment explicitly to avoid that.

Fixes #18044.

Change-Id: I8ccc131e60937d30c5f715a34c7803258833fc2f
Reviewed-on: https://go-review.googlesource.com/33872
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-12-02 07:13:18 +00:00
Ian Lance Taylor 45f759500e cmd/link: handle STT_COMMON symbols
Tested by running

GOTRACEBACK=2 CGO_CFLAGS="-Wa,--elf-stt-common=yes" go test -ldflags=-linkmode=internal

in misc/cgo/test. That failed before this CL, succeeded after.

I don't think it's worth doing that as a regular test, though,
especially since only recent versions of the GNU binutils support the
--elf-stt-common option.

Fixes #18088.

Change-Id: I893d86181faee217b1504c054b0ed3f7c8d977d3
Reviewed-on: https://go-review.googlesource.com/33653
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-11-29 02:15:04 +00:00
David Crawshaw 6f31abd23a cmd/compile, cmd/link: weak relocation for ptrTo
Introduce R_WEAKADDROFF, a "weak" variation of the R_ADDROFF relocation
that will only reference the type described if it is in some other way
reachable.

Use this for the ptrToThis field in reflect type information where it
is safe to do so (that is, types that don't need to be included for
interface satisfaction, and types that won't cause the compiler to
recursively generate an endless series of ptr-to-ptr-to-ptr-to...
types).

Also fix a small bug in reflect, where StructOf was not clearing the
ptrToThis field of new types.

Fixes #17931

Change-Id: I4d3b53cb9c916c97b3b16e367794eee142247281
Reviewed-on: https://go-review.googlesource.com/33427
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-11-22 03:10:14 +00:00
David Crawshaw 7ee7936523 cmd/link: handle R_GOTPCREL separately on darwin
To generate the correct section offset the shared code path for
R_CALL, R_PCREL, and R_GOTPCREL on darwin when externally linking
walks up the symbol heirarchy adding the differences. This is fine,
except in the case where we are generating a GOT lookup, because
the topmost symbol is left in r.Xsym instead of the symbol we are
looking up. So all funcsym GOT lookups were looking up the outer
"go.func.*" symbol.

Fix this by separating out the R_GOTPCREL code path.

For #17828 (and may fix it).

Change-Id: I2c9f4d135e77c17270aa064d8c876dc6d485d659
Reviewed-on: https://go-review.googlesource.com/33211
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-11-16 18:37:03 +00:00
David Crawshaw 03da2690c9 cmd/link, runtime, plugin: versioning
In plugins and every program that opens a plugin, include a hash of
every imported package.

There are two versions of each hash: one local and one exported.
As the program starts and plugins are loaded, the first exported
symbol for each package becomes the canonical version.

Any subsequent plugin's local package hash symbol has to match the
canonical version.

Fixes #17832

Change-Id: I4e62c8e1729d322e14b1673bada40fa7a74ea8bc
Reviewed-on: https://go-review.googlesource.com/33161
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-11-15 16:14:27 +00:00
Vladimir Stefanovic 5b147122d6 cmd/dist: add support for GOARCH=mips{,le}
Change-Id: I6e24d22eada190e9aa2adc161be7a753c8e5054b
Reviewed-on: https://go-review.googlesource.com/31514
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2016-11-12 00:34:21 +00:00
Ian Lance Taylor 53aec79ce0 cmd/link: for -buildmode=exe pass -no-pie to external linker
On some systems the external linker defaults to PIE. On some systems
DT_TEXTREL does not work correctly. When both are true we have a bad
situation: any Go program built with the default buildmode (exe) that
uses external linking will fail to run. Fix this by passing -no-pie to
the external linker, if the option is supported.

Fixes #17847.

Change-Id: I9b5ff97825d8b7f494f96d29c4c04f72b53dbf4e
Reviewed-on: https://go-review.googlesource.com/33106
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-11-11 14:26:15 +00:00
David Crawshaw eb4e17b73b cmd/link: use plugin path in visibility analysis
CL 32355 switched from using the output file as a
plugin prefix to the full package path. The linker dead code analysis
was not updated.

Updates #17821

Change-Id: I13fc45e0264b425d28524ec54c829e2c3e895b0b
Reviewed-on: https://go-review.googlesource.com/32916
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-11-11 00:10:03 +00:00
Vladimir Stefanovic 76d8e60451 cmd/link: add support for GOARCH=mips{,le}
Only internal linking without cgo is supported for now.

Change-Id: I772d2ba496a613c78bee7e93f29e9538e6407bdc
Reviewed-on: https://go-review.googlesource.com/31481
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2016-11-08 19:58:09 +00:00
Lynn Boger ec77b8e09c cmd/link: don't use trampolines in ppc64le ext linking
On ppc64x, trampolines are used to resolve too-far
branches for internal linking.  The external linking,
solution on ppc64x is to split text sections when they
get too large, allowing the external linker to handle
the long branches.

On arm trampolines are generanted for too-far branches
for internal and external linking.  When the change
was made recently to enable trampolines for external linking
on arm, that broke the ppc64x fix for too-far branches
with external linking.

The fix adds a check to use trampolines only for internal
linking with ppc64x.

Fixes #17795

Change-Id: Icce968fb96545f10a913e07654514643bce96261
Reviewed-on: https://go-review.googlesource.com/32853
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
2016-11-07 15:03:24 +00:00
Vladimir Stefanovic 585a0b03b2 cmd/link/internal/ld: add support for GOARCH=mips{,le}
Change-Id: Ida214ccc5858969ea60abb0787f4d98bab4336d6
Reviewed-on: https://go-review.googlesource.com/31480
TryBot-Result: Gobot Gobot <gobot@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2016-11-04 19:27:35 +00:00
David Crawshaw 8eb9fdaa01 cmd/compile: write type symbols referenced in ptabs
The exported symbol for a plugin can be the only reference to a
type in a program. In particular, "var F func()" will have
the type *func(), which is uncommon.

Fixes #17140

Change-Id: Ide2104edbf087565f5377374057ae54e0c00c57e
Reviewed-on: https://go-review.googlesource.com/29692
Run-TryBot: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2016-11-03 14:07:34 +00:00
David Crawshaw d0e408334b cmd/link: support plugins with no exported symbols
A plugin with no exported symbols is still potentially very useful.
Its init functions are called on load, and it so it can have visible
side effects.

Fixes #17681

Change-Id: Icdca31f48e5ab13c99020a2ef724f3de47dcd74b
Reviewed-on: https://go-review.googlesource.com/32437
Run-TryBot: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-11-01 20:56:30 +00:00
David Crawshaw 9da7058466 cmd/link, plugin: use full plugin path for symbols
Plumb the import path of a plugin package through to the linker, and
use it as the prefix on the exported symbol names.

Before this we used the basename of the plugin file as the prefix,
which could conflict and result in multiple loaded plugins sharing
symbols that are distinct.

Fixes #17155
Fixes #17579

Change-Id: I7ce966ca82d04e8507c0bcb8ea4ad946809b1ef5
Reviewed-on: https://go-review.googlesource.com/32355
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-10-31 04:48:42 +00:00
Russ Cox 1773cdd081 cmd/link: fix -X importpath.name=value when import path needs escaping
After the final slash, dots are %-escaped when constructing a symbol name,
so that in the actual symbol table, the import path githost.com/my.git
becomes githost.com/my%2egit. In this case, -X githost.com/my.git.Value=foo
needs to set githost.com/my%2egit.Value. This is a detail of the object format
and not something users should know or depend on, so apply the escaping
as needed.

People who have run across this already and figured out and started using
the escaped forms with -X will find those forms not working anymore.
That is, -X githost.com/my%2egit.Value=foo is the Go 1.7 workaround but
will stop working in Go 1.8 once this proper fix is in place.
People who need to keep scripts working with older and newer versions of Go
can safely pass both forms, and one will be ignored:

    -X githost.com/my%2egit.Value=foo -X githost.com/my.git.Value=foo

Fixes #16710.

Change-Id: I0e994ccdd412a4eb8349fefce9aeb3bfc9a83cd8
Reviewed-on: https://go-review.googlesource.com/31970
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-10-29 18:24:52 +00:00
Cherry Zhang 9d1efba28d cmd/link: put text at address 0x1000000 on darwin/amd64
Apparently on macOS Sierra LLDB thinks /usr/lib/dyld is mapped
at address 0, even if Go code starts at 0x1000, and it looks up
addresses from dyld which shadows Go symbols. Move Go binary at
a higher address to avoid clash.

Fixes #17463. Re-enable TestLldbPython.

Change-Id: I89ca6f3ee48aa6da9862bfa0c2da91477cc93255
Reviewed-on: https://go-review.googlesource.com/32185
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Quentin Smith <quentin@golang.org>
2016-10-28 20:17:53 +00:00
shaharko d8d445280a cmd/compile, cmd/link: more efficient typelink generation
Instead of generating typelink symbols in the compiler
mark types that should have typelinks with a flag.
The linker detects this flag and adds the marked types
to the typelink table.

name            old s/op    new s/op    delta
LinkCmdCompile   0.27 ± 6%   0.25 ± 6%  -6.93%    (p=0.000 n=97+98)
LinkCmdGo        0.30 ± 5%   0.29 ±10%  -4.22%    (p=0.000 n=97+99)

name            old MaxRSS  new MaxRSS  delta
LinkCmdCompile   112k ± 3%   106k ± 2%  -4.85%  (p=0.000 n=100+100)
LinkCmdGo        107k ± 3%   103k ± 3%  -3.00%  (p=0.000 n=100+100)

Change-Id: Ic95dd4b0101e90c1fa262c9c6c03a2028d6b3623
Reviewed-on: https://go-review.googlesource.com/31772
Run-TryBot: Shahar Kohanim <skohanim@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-10-25 19:44:06 +00:00
shaharko 80a034642e cmd/compile, cmd/link: stop generating unused go.string.hdr symbols.
name       old s/op    new s/op    delta
LinkCmdGo   0.29 ± 5%   0.29 ± 8%  -2.60%   (p=0.000 n=97+98)

name       old MaxRSS  new MaxRSS  delta
LinkCmdGo   106k ± 4%   105k ± 3%  -1.00%  (p=0.000 n=100+99)

Change-Id: I75a1c3b24ea711a15a5d2eae026b70b97ee7bad4
Reviewed-on: https://go-review.googlesource.com/31030
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
2016-10-25 05:17:05 +00:00
Alex Brainman 02c1d8a158 cmd/link/internal/ld: remove goto from ldpe.go
Updates #15345

Change-Id: I447d133512e99a9900928a910e161a85db6e8b75
Reviewed-on: https://go-review.googlesource.com/31792
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-25 01:22:29 +00:00
Russ Cox 8419c85eaa runtime, cmd/link: fix netbsd/arm EABI support
Fixes reported by oshimaya (see #13806).

Fixes #13806.

Change-Id: I9b659ab918a34bc5f7c58f3d7f59058115b7f776
Reviewed-on: https://go-review.googlesource.com/31651
Reviewed-by: Minux Ma <minux@golang.org>
2016-10-24 15:23:13 +00:00
Ian Lance Taylor e32ac7978d cmd/link, cmd/internal/obj: stop exporting various names
Just happened to notice that these names (funcAlign and friends) are
never referenced outside their package, so no need to export them.

Change-Id: I4bbdaa4b0ef330c3c3ef50a2ca39593977a83545
Reviewed-on: https://go-review.googlesource.com/31496
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-10-19 21:16:58 +00:00
Matthew Dempsky 99b7984de7 cmd/link: remove some unnecessary comments
The comments about pcln functions are obsolete since those functions
now live in cmd/internal/obj. The copyright header is redundant with
the existing one at the top of the file.

Change-Id: I568fd3d259253a0d8eb3b0a157d008df1b5de106
Reviewed-on: https://go-review.googlesource.com/31315
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-10-17 22:00:55 +00:00
Cherry Zhang c7e855658d cmd/link: trampoline support for external linking on ARM
all.bash passes with -debugtramp=2 (except the unavoidable
disassembly test as we change instructions). And successfully
build k8s.io/kubernetes/cmd/hyperkube in both internal linking
and external linking mode.

Fixes #17028.

Change-Id: Ic8fac6a394488155c5eba9215662db1c1086e24b
Reviewed-on: https://go-review.googlesource.com/31143
Reviewed-by: David Chase <drchase@google.com>
2016-10-17 21:38:06 +00:00
Lynn Boger d26b0661c2 cmd/link: add trampolines for too far calls in ppc64x
This change adds support for trampolines on ppc64x when using
internal linking, in the case where the offset to the branch
target is larger than what fits in the field provided by the
branch instruction.

Fixes #16665

Change-Id: Icfee72910f38c94588d2adce517b64dee6176145
Reviewed-on: https://go-review.googlesource.com/30850
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2016-10-17 16:06:04 +00:00
Russ Cox 237d7e34bc cmd/dist: use debug/pe directly for cmd/link
Delete vendored copy.

Change-Id: I06e9d3b709553a1a8d06275e99bd8f617aac5788
Reviewed-on: https://go-review.googlesource.com/31011
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-10-17 15:22:17 +00:00
Alex Brainman d08c3d1329 cmd/link/internal/ld: use debug/pe package to rewrite ldpe.go
This CL also includes vendored copy of debug/pe,
otherwise bootstrapping fails.

Updates #15345

Change-Id: I3a8ac990e3cb12cb4d24ec11b618b68190397fd1
Reviewed-on: https://go-review.googlesource.com/22603
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-13 19:11:02 +00:00
David Crawshaw 413afcafbf cmd/link: force external linking for plugins
Fixes #17415

Change-Id: I6f896d549092e5e0dba72351e5385992b4cbe90f
Reviewed-on: https://go-review.googlesource.com/30933
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-10-12 17:26:34 +00:00
David du Colombier 9d36ab222d cmd/link: use HEADR to define FlagTextAddr (cosmetic change)
This cosmetic change defines ld.FlagTextAddr using ld.HEADR in
the Plan 9 cases, like it is done for other operating systems.

Change-Id: Ic929c1c437f25661058682cf3e159f0b16cdc538
Reviewed-on: https://go-review.googlesource.com/30912
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-10-12 13:18:34 +00:00
David du Colombier 29c600bba1 cmd/link: fix build on plan9/amd64
Support for multiple text sections was added in CL 27790.
However, this change broke the build on plan9/amd64.

In relocsym, the R_ADDROFF relocation was changed to
use offsets relative to the start of the first text
section. However, Segtext.Vaddr is the address of
the text segment, while we expect to start from
the first section (text.runtime) of the text segment.

Fixes #17411.

Change-Id: I86bbcbda81cea735b0ecf156eab2e6e5d63acce3
Reviewed-on: https://go-review.googlesource.com/30911
Run-TryBot: David du Colombier <0intro@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-10-12 13:14:46 +00:00
Shawn Walker-Salas f373bf1eb9 cmd/link: non-executable stack support for Solaris
Support the tagging of binaries created with the internal linker
on Solaris as having a non-executable stack by writing a PT_SUNWSTACK
program header.

Fixes #16074

Change-Id: I3888f2153083385d04a52f341570f93e5738b276
Reviewed-on: https://go-review.googlesource.com/24142
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2016-10-12 06:41:25 +00:00
Cherry Zhang 7c431cb7f9 cmd/link: insert trampolines for too-far jumps on ARM
ARM direct CALL/JMP instruction has 24 bit offset, which can only
encodes jumps within +/-32M. When the target is too far, the top
bits get truncated and the program jumps wild.

This CL detects too-far jumps and automatically insert trampolines,
currently only internal linking on ARM.

It is necessary to make the following changes to the linker:
- Resolve direct jump relocs when assigning addresses to functions.
  this allows trampoline insertion without moving all code that
  already laid down.
- Lay down packages in dependency order, so that when resolving a
  inter-package direct jump reloc, the target address is already
  known. Intra-package jumps are assumed never too far.
- a linker flag -debugtramp is added for debugging trampolines:
    "-debugtramp=1 -v" prints trampoline debug message
    "-debugtramp=2"    forces all inter-package jump to use
                       trampolines (currently ARM only)
    "-debugtramp=2 -v" does both
- Some data structures are changed for bookkeeping.

On ARM, pseudo DIV/DIVU/MOD/MODU instructions now clobber R8
(unfortunate). In the standard library there is no ARM assembly
code that uses these instructions, and the compiler no longer emits
them (CL 29390).

all.bash passes with -debugtramp=2, except a disassembly test (this
is unavoidable as we changed the instruction).

TBD: debug info of trampolines?

Fixes #17028.

Change-Id: Idcce347ea7e0af77c4079041a160b2f6e114b474
Reviewed-on: https://go-review.googlesource.com/29397
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-11 13:35:33 +00:00
John Dethridge 8f65379f94 cmd/link: more efficient encoding of DWARF line number information
The (pc, line) deltas in the line number information are currently encoded
either with a special opcode, or with a triplet of DW_LNS_advance_pc,
DW_LNS_advance_line, and DW_LNS_copy instructions.  Instead of DW_LNS_copy,
this change always uses a special opcode, which can make DW_LNS_advance_pc or
DW_LNS_advance_line unnecessary, or make their operands take fewer bytes.  It
chooses the special opcode so that the encoding of the remaining deltas is as
small as possible.

Use DW_LNS_const_add_pc or DW_LNS_fixed_advance_pc instead of DW_LNS_advance_pc
for deltas where they save a byte.

Update LINE_BASE and LINE_RANGE constants to optimal values for this strategy.

This reduces line number information by about 35% and total size by about 2%
for a typical binary.

Change-Id: Ia61d6bf19c95c1d34ba63c67ed32b376beda225f
Reviewed-on: https://go-review.googlesource.com/30577
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-11 01:42:35 +00:00
Alberto Donizetti 590f3f0c9d cmd/compile: fix misaligned comments
Realign multi-line comments that got misaligned by the c->go
conversion.

Change-Id: I584b902e95cf588aa14febf1e0b6dfa499c303c2
Reviewed-on: https://go-review.googlesource.com/29871
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-09-27 14:00:39 +00:00
David Crawshaw 73e7a569b4 cmd/link: plugin support on darwin/amd64
This CL turns some special section marker symbols into real symbols
laid out in the sections they mark. This is to deal with the fact
that dyld on OS X resolves the section marker symbols in any dlopen-ed
Go program to the original section marker symbols in the host program.

More details in a comment in cmd/link/internal/ld/data.go.

Change-Id: Ie9451cfbf06d0bdcccb9959219c791b829f3f771
Reviewed-on: https://go-review.googlesource.com/29394
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-23 22:58:57 +00:00
Russ Cox 404ae84aa2 cmd/link: add time stamp to hostlink print in -v mode
Change-Id: I128b142aee5e1b917e7ba63b48512972f053ea0b
Reviewed-on: https://go-review.googlesource.com/29531
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-21 20:25:48 +00:00
Lynn Boger b4efd09d18 cmd/link: split large elf text sections on ppc64x
Some applications built with Go on ppc64x with external linking
can fail to link with relocation truncation errors if the elf
text section that is generated is larger than 2^26 bytes and that
section contains a call instruction (bl) which calls a function
beyond the limit addressable by the 24 bit field in the
instruction.

This solution consists of generating multiple text sections where
each is small enough to allow the GNU linker to resolve the calls
by generating long branch code where needed.  Other changes were added
to handle differences in processing when multiple text sections exist.

Some adjustments were required to the computation of a method's address
when using the method offset table when there are multiple text sections.

The number of possible section headers was increased to allow for up
to 128 text sections.  A test case was also added.

Fixes #15823.

Change-Id: If8117b0e0afb058cbc072258425a35aef2363c92
Reviewed-on: https://go-review.googlesource.com/27790
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-21 20:23:49 +00:00
Michael Hudson-Doyle 836a3ae663 cmd/link: remove more unused ctxt parameters
This time in elf.go.

Change-Id: Ifaf71742ebbc9aadc8606c39ea2d417ae5cc7e0d
Reviewed-on: https://go-review.googlesource.com/29450
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-20 04:21:16 +00:00
Michael Hudson-Doyle b6324ef5ff cmd/link: kill off Symbols.Version
Change-Id: Iee8f773355870f2333637a093e51c5fd36e5a6e5
Reviewed-on: https://go-review.googlesource.com/29349
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-20 04:20:50 +00:00
Michael Hudson-Doyle 6383709272 cmd/link: remove now-unused ctxt arguments from a few functions
Specifically Addstring, Addbytes and Symgrow.

Change-Id: Ia74093bfcf9f360bf223accbc8feef54a7f059c9
Reviewed-on: https://go-review.googlesource.com/29348
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-20 04:13:16 +00:00
Michael Hudson-Doyle 25d094034b cmd/link: remove Linklookup & Linkrlookup
Change-Id: I25d9f74cb52e6fd4f2ad4b1c8b7102efadbc7481
Reviewed-on: https://go-review.googlesource.com/29344
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-20 04:12:57 +00:00
Michael Hudson-Doyle 324f6ab48c cmd/link: use ctxt.{Lookup,ROLookup} in favour of function versions of same
Done with two eg templates:

package p

import (
	"cmd/link/internal/ld"
)

func before(ctxt *ld.Link, name string, v int) *ld.Symbol {
	return ld.Linklookup(ctxt, name, v)
}
func after(ctxt *ld.Link, name string, v int) *ld.Symbol {
	return ctxt.Syms.Lookup(name, v)
}

package p

import (
	"cmd/link/internal/ld"
)

func before(ctxt *ld.Link, name string, v int) *ld.Symbol {
	return ld.Linkrlookup(ctxt, name, v)
}
func after(ctxt *ld.Link, name string, v int) *ld.Symbol {
	return ctxt.Syms.ROLookup(name, v)
}

Change-Id: I00647dbf62294557bd24c29ad1f108fc786335f1
Reviewed-on: https://go-review.googlesource.com/29343
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-20 04:12:43 +00:00
Michael Hudson-Doyle d41a7f77c5 cmd/link: do not directly embed Symbols in Link
Mostly done with sed.

Change-Id: Ic8c534a3fdd332b5420d062ee85bb77a30ad1efb
Reviewed-on: https://go-review.googlesource.com/29346
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-20 04:12:28 +00:00
Michael Hudson-Doyle d284d4ff92 cmd/link: split "bag of Symbols" functionality out of Link
Mechanical refactorings to follow.

Change-Id: I9b98e69a58c3cba7c7d1d3e3f600d4ed99d4fce2
Reviewed-on: https://go-review.googlesource.com/29342
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-20 04:12:12 +00:00
David Crawshaw e9fddf8f86 cmd/internal/obj, cmd/link: darwin dynlink support
This makes it possible for cmd/compile, when run with -dynlink on
darwin/amd64, to generate TLS_LE relocations which the linker then
turns into the appropriate PC-relative GOT load.

Change-Id: I1a71da432608bdb108ff66c22de600100209c873
Reviewed-on: https://go-review.googlesource.com/29393
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-20 03:15:15 +00:00
David Crawshaw 1d3fae461c cmd/link: remove Cursym
Change-Id: I58253a6cd2d77a9319c0783afb0d92cd5a88a7f7
Reviewed-on: https://go-review.googlesource.com/29370
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
2016-09-20 02:42:16 +00:00
David Crawshaw 5a597e2d29 cmd/link: replace ld.Link.Diag with ld.Errorf
Instead of using ctxt.Cursym, Errorf takes an explicit *Symbol
parameter. This removes most uses of Cursym and means the *Link
context object is needed in fewer parts of the linker.

All transformations done manually, as wiring Cursym is tricky.

Change-Id: Ief88b00b73904224675c0035684c3a84c19249d7
Reviewed-on: https://go-review.googlesource.com/29369
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-20 02:36:39 +00:00
Michael Hudson-Doyle 50644f2e67 cmd/link: move comment somewhere more appropriate
At least, I assume it's meant to be here. It makes no sense at all where it
currently is.

Change-Id: Ic6a6c112c3dcf1318256d7d602168c3446b55412
Reviewed-on: https://go-review.googlesource.com/29339
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-19 21:42:57 +00:00
Michael Hudson-Doyle dcb954c3f7 cmd/link: remove size and version from genasmsym's argument
They are trivially available in the few places they are needed.

Change-Id: I6544692e9027076ec9e6e9a295c66457039e55e1
Reviewed-on: https://go-review.googlesource.com/29332
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-18 21:59:20 +00:00
Michael Hudson-Doyle 2266047556 cmd/link: give names and a type to the symbol types used by genasmsym
Doing this revealed some dead code.

Change-Id: I5202fcc3f73e3dfddfea3ec7b772e16da51195da
Reviewed-on: https://go-review.googlesource.com/29331
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-18 21:59:09 +00:00
David Crawshaw f323a7c6d2 cmd/link: remove never-set Windows variable
Change-Id: I3d64549b85b71bb63bcc815ce2276af6ca2eb215
Reviewed-on: https://go-review.googlesource.com/29354
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-16 21:11:57 +00:00
David Crawshaw 28ed2b0cd9 cmd/link: skip arch-specific main function
Add some notes to main.go on what happens where.

Change-Id: I4fb0b6c280e5f990ddc5d749267372b86870af6d
Reviewed-on: https://go-review.googlesource.com/28970
TryBot-Result: Gobot Gobot <gobot@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-16 20:38:38 +00:00
David Crawshaw b87d7a5cf6 cmd/link: give RelocVariant a type, document Reloc
Change-Id: Ib20263405a08674b5e160295fc965da4c8b54b34
Reviewed-on: https://go-review.googlesource.com/29248
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-16 18:30:27 +00:00
David Crawshaw 6007c8c76b cmd/link: attempt to rationalize linkmode init
This CL gives Linkmode a type, switches it to the standard flag
handling mechanism, and deduplicates some logic.

There is a semantic change in this CL. Previously if a link was
invoked explicitly with -linkmode=internal, any condition that forced
external linking would silently override this and use external
linking. Instead it now fails with a reason why. I believe this is an
improvement, but will change it back if there's disagreement.

Fixes #12848

Change-Id: Ic80e341fff65ecfdd2b6fdd6079674cc7210fc5f
Reviewed-on: https://go-review.googlesource.com/28971
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-16 17:57:53 +00:00
David Crawshaw eced6754c2 cmd/link: -buildmode=plugin support for linux
This CL contains several linker changes to support creating plugins.

It collects the exported plugin symbols provided by the compiler and
includes them in the moduledata.

It treats a binary as being dynamically linked if it imports the plugin
package. This lets the dynamic linker de-duplicate symbols.

Change-Id: I099b6f38dda26306eba5c41dbe7862f5a5918d95
Reviewed-on: https://go-review.googlesource.com/27820
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-16 14:49:13 +00:00
Cherry Zhang bb12894d2b cmd/link: fix number-of-files entry in gopclntab
According to golang.org/s/go12symtab, for N files, it should put N+1
there.

Fixes #17132.

Change-Id: I0c84136855c6436be72b9d3c407bf10d4c81a099
Reviewed-on: https://go-review.googlesource.com/29275
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-09-16 01:41:56 +00:00
Josh Bleecher Snyder 83676b93fb cmd/compile, cmd/link: fix printf verbs
Found by vet.

Change-Id: I9dbc6208ddbb5b407f4ddd20efbc166aac852cf7
Reviewed-on: https://go-review.googlesource.com/29162
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-09-14 18:50:45 +00:00
David Crawshaw 5940a007c1 cmd/link: R_ADDR dynamic relocs for internal PIE
This gets -buildmode=pie -ldflags=-linkmode=internal working on
Ubuntu 16.04.

Fixes #17068

Change-Id: Ice5036199005fb528cc58279a7f057170dc6b73d
Reviewed-on: https://go-review.googlesource.com/29118
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-14 13:27:30 +00:00
David Crawshaw 567aefd99d cmd/link: address comments from CL 28540
Change-Id: I11899096c71ee0e24e902c87914601fcd7ffd7a9
Reviewed-on: https://go-review.googlesource.com/28967
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-13 23:34:46 +00:00
Michael Hudson-Doyle 8f9671d11a cmd/link: fix -buildmode=pie / -linkshared combination
main.main and main.init were not being marked as reachable.

Fixes #17076

Change-Id: Ib3e29bd35ba6252962e6ba89173ca321ed6849b9
Reviewed-on: https://go-review.googlesource.com/28996
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-13 02:40:30 +00:00
David Crawshaw d185cc3b64 cmd/link: disable internal PIE for now
There's more work to do.

Updates #17068

Change-Id: I4e16c0e8e9ac739e1fe266224c3769f6c5b2e070
Reviewed-on: https://go-review.googlesource.com/29076
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-12 18:21:29 +00:00
David Crawshaw 1a42d8fbd6 cmd/link: allow internal PIE linking
Part of adding PIE internal linking on linux/amd64.

Change-Id: I5ce01d1974e5d4b1a8cbcc8b08157477631d8d24
Reviewed-on: https://go-review.googlesource.com/28543
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-11 21:53:21 +00:00
David Crawshaw 04b4dbe1f0 cmd/link: mark PIE binaries as ET_DYN
Part of adding PIE internal linking on linux/amd64.

Change-Id: I586e7c2afba349281168df5e20d2fdcb697f6e37
Reviewed-on: https://go-review.googlesource.com/28542
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-11 21:30:09 +00:00
David Crawshaw d9d1399eea cmd/link: mark rel.ro segment as PT_GNU_RELRO
Details: http://www.airs.com/blog/archives/189

Part of adding PIE internal linking on linux/amd64.

Change-Id: I8843a97f22f6f120346cccd694c7fff32f09f60b
Reviewed-on: https://go-review.googlesource.com/28541
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-11 21:29:51 +00:00
David Crawshaw 44ee2b00db cmd/link: optimize TLS IE to LE in build mode PIE
When cmd/compile generates position-independent code on linux
(the -shared flag), it refers to runtime.tlsg as a TLS IE variable.

When cmd/link is linking a PIE executable internally, all TLS IE
relocations are generated by cmd/compile, and the variable they
refer to, runtime.tlsg, is local to the binary. This means we can
optimize this particular IE case to LE, and thus implement IE
support when internally linking.

To do this optimization in the linker, we need to rewrite the
PC-relative MOVD to a constant load. This may seem like an
unconscionable act born of enthusiasm, but it turns out this is
standard operating procedure for linkers. GNU gold does exactly
the same optimization. I spent some time reading it and documented
at least one missing feature from this version.

Part of adding PIE internal linking on linux/amd64.

Change-Id: I1eb068d0ec774724944c6b308aa5084582ecde0b
Reviewed-on: https://go-review.googlesource.com/28540
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-11 21:13:42 +00:00
David Crawshaw 81ee93679d cmd/link: generate dynamic relocs for internal PIE
This reuses the machinery built for dynamic loading of shared
libraries. The significant difference with PIE is we generate
dynamic relocations for known internal symbols, not just
dynamic external symbols.

Part of adding PIE internal linking on linux/amd64.

Change-Id: I4afa24070bfb61f94f8d3648f2433d5343bac3fe
Reviewed-on: https://go-review.googlesource.com/28539
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-11 20:30:47 +00:00
David Crawshaw 276803d611 cmd/link: introduce a rel.ro segment
When internally linking with using rel.ro sections, this segment covers
the sections. To do this, move to other read-only sections, SELFROSECT
and SMACHOPLT, out of the way.

Part of adding PIE internal linking on linux/amd64.

Change-Id: I4fb3d180e92f7e801789ab89864010faf5a2cb6d
Reviewed-on: https://go-review.googlesource.com/28538
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-11 20:10:47 +00:00
Josh Bleecher Snyder 0e435347b1 cmd: fix format strings used with obj.Headtype
Found by vet. Introduced by CL 28853.

Change-Id: I3199e0cbdb1c512ba29eb7e4d5c1c98963f5a954
Reviewed-on: https://go-review.googlesource.com/28957
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-09-10 21:40:10 +00:00
David Crawshaw 3877f820a6 cmd/link, etc: introduce SymKind type
Moves the grouping of symbol kinds (sections) into cmd/internal/obj
to keep it near the definition. Groundwork for CL 28538.

Change-Id: I99112981e69b028f366e1333f31cd7defd4ff82c
Reviewed-on: https://go-review.googlesource.com/28691
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-09 16:56:03 +00:00
David Crawshaw 791f71d192 cmd: use obj.GOOS, obj.GOARCH, etc
As cmd/internal/obj is coordinating the definition of GOOS, GOARCH,
etc across the compiler and linker, turn its functions into globals
and use them everywhere.

Change-Id: I5db5addda3c6b6435c37fd5581c7c3d9a561f492
Reviewed-on: https://go-review.googlesource.com/28854
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-09-09 16:38:45 +00:00
David Crawshaw 428c349552 cmd/link, cmd/internal/obj: give Headtype a type
Separate out windows/windowsgui properly so we are not encoding some
of the Headtype value in a separate headstring global.

Remove one of the two copies of the variable from cmd/link.

Remove duplicate string to headtype list.

Change-Id: Ifa20fb9652a1dc95161e154aac11f15ad0f709d0
Reviewed-on: https://go-review.googlesource.com/28853
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-09 12:25:00 +00:00
David Crawshaw 361d2738d5 cmd/link: remove the -shared flag
The -shared flag has been superseded by the -buildmode flag.

Change-Id: I3682cc0367b919084c280d7dc64746485c1d4ddd
Reviewed-on: https://go-review.googlesource.com/28852
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
2016-09-09 10:20:01 +00:00
David Crawshaw b926bf83b0 cmd/link: remove outdated cast and comment
This program is written in Go now.

Change-Id: Ieec21a1bcac7c7a59e88cd1e1359977659de1757
Reviewed-on: https://go-review.googlesource.com/28549
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-06 17:21:22 +00:00
Alex Brainman dfbbe06a20 cmd/link, cmd/go: delay linking of mingwex and mingw32 until very end
cmd/go links mingwex and mingw32 libraries to every package it builds.
This breaks when 2 different packages call same gcc standard library
function pow. gcc linker appends pow implementation to the compiled
package, and names that function "pow". But when these 2 compiled
packages are linked together into the final executable, linker
complains, because it finds two "pow" functions with the same name.

This CL stops linking of mingwex and mingw32 during package build -
that leaves pow function reference unresolved. pow reference gets
resolved as final executable is built, by having both internal and
external linker use mingwex and mingw32 libraries.

Fixes #8756

Change-Id: I50ddc79529ea5463c67118d668488345ecf069bc
Reviewed-on: https://go-review.googlesource.com/26670
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-08-31 06:30:26 +00:00
Emmanuel Odeke 7c04633e0c all: fix obsolete inferno-os links
Fixes #16911.

Fix obsolete inferno-os links, since code.google.com shutdown.
This CL points to the right files by replacing
http://code.google.com/p/inferno-os/source/browse
with
https://bitbucket.org/inferno-os/inferno-os/src/default

To implement the change I wrote and ran this script in the root:
$ grep -Rn 'http://code.google.com/p/inferno-os/source/browse' * \
| cut -d":" -f1 | while read F;do perl -pi -e \
's/http:\/\/code.google.com\/p\/inferno-os\/source\/browse/https:\/\/bitbucket.org\/inferno-os\/inferno-os\/src\/default/g'
$F;done

I excluded any cmd/vendor changes from the commit.

Change-Id: Iaaf828ac8f6fc949019fd01832989d00b29b6749
Reviewed-on: https://go-review.googlesource.com/27994
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-08-29 04:54:42 +00:00
David Crawshaw 8f3c8a33fa cmd/link: make DynlinkingGo a method
This will allow it to depend on whether plugin.Open is a symbol to be
linked in.

Change-Id: Ie9aa4216f2510fe8b10bc4665c8b19622b7122ea
Reviewed-on: https://go-review.googlesource.com/27819
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-08-26 20:06:58 +00:00
Michael Hudson-Doyle 7c3fc4b8e4 cmd/link: hide funcsym symbols
As far as I can tell, this check has been
non-functional since it was introduced.

This cuts 57k off cmd/go and 70k off cmd/compile.

Based on golang.org/cl/24710 by Josh Bleecher Snyder.

Change-Id: I1162a066971df1a067b50afa1cfa0819a6913574
Reviewed-on: https://go-review.googlesource.com/27830
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-08-26 01:06:13 +00:00
Dave Cheney d61c07ffd8 cmd/link/internal, cmd/internal/obj: introduce ctxt.Logf
Replace the various calls to Fprintf(ctxt.Bso, ...) with a helper,
ctxt.Logf. This also addresses the various inconsistent flushing of
ctxt.Bso.

Because we have two Link structures, add Link.Logf in both places.

Change-Id: I23093f9b9b3bf33089a0ffd7f815f92dcd1a1fa1
Reviewed-on: https://go-review.googlesource.com/27730
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-08-25 03:34:06 +00:00
Dave Cheney 5f94ff4c87 cmd/link/internal/ld: move ld.Cpos to coutbuf.Offset
This change moves the ld.Cpos function to a method on coutbuf. This is
part of a larger change that makes ld.outbuf look more like a bio.Buf in
an effort to eventually replace the former with the latter.

Change-Id: I506f7131935a2aa903fa302a0fab0c5be50220fd
Reviewed-on: https://go-review.googlesource.com/27578
Run-TryBot: Dave Cheney <dave@cheney.net>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-08-25 02:57:48 +00:00
Dave Cheney 3167ff7ca9 cmd/internal/*: only call ctx.Bso.Flush when something has been written
In many places where ctx.Bso.Flush is used as the target for some debug
logging, ctx.Bso.Flush is called unconditionally. In the majority of
cases where debug logging is not enabled, this means Flush is called
many times when there is nothing to be flushed (it will be called anyway
when ctx.Bso is eventually closed), sometimes in a loop.

Avoid this by moving the ctx.Bso.Flush call into the same condition
block as the debug print. This pattern was previously applied
sporadically.

Change-Id: I0444cb235cc8b9bac51a59b2e44e59872db2be06
Reviewed-on: https://go-review.googlesource.com/27579
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-08-25 01:31:17 +00:00
Keith Randall a99f812cba cmd/objdump: implement objdump of .o files
Update goobj reader so it can provide all the information
necessary to disassemble .o (and .a) files.

Grab architecture of .o files from header.

.o files have relocations in them.  This CL also contains a simple
mechanism to disassemble relocations and add relocation info as an extra
column in the output.

Fixes #13862

Change-Id: I608fd253ff1522ea47f18be650b38d528dae9054
Reviewed-on: https://go-review.googlesource.com/24818
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-08-24 17:36:59 +00:00
Michael Matloob 24158644dd cmd/link/internal/ld: camelCase a buch of snake_case names
I've also unexported a few symbols that weren't used outside the
package.

Updates #16818

Change-Id: I39d9d87b3eec30b88b4a17c1333cfbbfa6b3518f
Reviewed-on: https://go-review.googlesource.com/27468
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-08-23 16:28:59 +00:00
Ian Lance Taylor d92a3606f5 cmd/go, cmd/link: build c-archive as position independent on ELF
This permits people to use -buildmode=c-archive to produce an archive
file that can be included in a PIE or shared library.

Change-Id: Ie340ee2f08bcff4f6fd1415f7d96d51ee3a7c9a1
Reviewed-on: https://go-review.googlesource.com/24180
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-08-23 13:12:56 +00:00
Ian Lance Taylor d9504d4623 cmd/link: don't record interpreter in flagInterpreter
Keep flagInterpreter unchanged after flag parsing. This lets us replace
flagInterpreterSet with flagInterpreter != "".

Change-Id: Ifd2edbb2ce0011e97276ca18281b8ffbabde1c50
Reviewed-on: https://go-review.googlesource.com/27563
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-08-23 13:10:12 +00:00
Ian Lance Taylor 93b753f525 cmd/link: fix handling of cgo_dynamic_interpreter
CL 27473 accidentally changed `!Debug['I']` to `*flagInterpreter != ""`.
Since the old `Debug['I']` was set when the new *flagInterpreter was
set, this inverted the sense of the condition. The effect was to always
ignore the cgo_dynamic_interpreter setting from runtime/cgo. This worked
OK when the default interpreter was the correct one, but failed when it
was not, as is currently the case on, at least, PPC64 and ARM.

This CL restores the old behavior by using a separate variable to track
whether the -I flag was used, just as we used to.

Change-Id: Icf9b65fa41349ed2e4de477fec0a557ef1eb8189
Reviewed-on: https://go-review.googlesource.com/27562
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-08-23 05:08:46 +00:00
Michael Matloob 550caa1c87 cmd/link/internal/mips64: fix use of -s flags
My flags change reversed the meaning of -s within mips64's
linker code. This should fix that.

Change-Id: Ia24002469e557fb29badfd830134e61c1dd7e16e
Reviewed-on: https://go-review.googlesource.com/27555
Reviewed-by: Minux Ma <minux@golang.org>
2016-08-22 22:59:20 +00:00
Michael Matloob fa8a28d559 cmd/link: turn some globals into flag pointer variables
This moves many of the flag globals into main and assigns them
to their flag.String/Int64/... directly.

Updates #16818

Change-Id: Ibbff44a273bbc5cb7228e43f147900ee8848517f
Reviewed-on: https://go-review.googlesource.com/27473
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-08-22 14:09:05 +00:00
Michael Hudson-Doyle 82c1e22e13 cmd/link: make listsort less generic
It's always called with the same arguments now.

Maybe the real fix is to make Symbol.Sub a slice but that requires a bit more
brain.

Change-Id: I1326d34a0a327554be6d54f9bd402ea328224766
Reviewed-on: https://go-review.googlesource.com/27416
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>
2016-08-22 01:55:12 +00:00
Michael Matloob 16e3ce2785 cmd/link/internal/ld: rename pobj.go to main.go
The only thing pobj contains is the Ldmain function.

Updates #16818

Change-Id: Id114bdb264cb5ea2f372eb2166201f1f8eb99445
Reviewed-on: https://go-review.googlesource.com/27472
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-08-21 23:00:44 +00:00
Michael Matloob 0a15d95091 cmd/link: use standard library flag package where possible
The obj library's flag functions are (mostly) light wrappers
around the standard library flag package. Use the flag package
directly where possible.

Most uses of the 'count'-type flags (except for -v) only check
against 0, so they can safely be replaced by bools. Only -v
and the flagfns haven't been replaced.

Debug has been turned into a slice of bools rather than ints.
There was a copy of the -v verbosity in ctxt.Debugvlog, so don't use
Debug['v'] and just use ctxt.Debugvlog.

Updates #16818

Change-Id: Icf6473a4823c9d35513bbd0c34ea02d5676d782a
Reviewed-on: https://go-review.googlesource.com/27471
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-08-21 23:00:27 +00:00
Michael Hudson-Doyle 8e90b9026b cmd/link: remove references to LSym (now Symbol)
Mostly comments but some derived names too.

Change-Id: I1e01dccca98de6688e1426c7a9309f6fd6a1e368
Reviewed-on: https://go-review.googlesource.com/27415
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-08-21 22:43:20 +00:00
Michael Hudson-Doyle 85072d5f75 cmd/link: remove Symbol.Next
Bye bye one more class of linked list manipulation!

Change-Id: I2412b224c847dd640f9253125d30cd5f911ce00c
Reviewed-on: https://go-review.googlesource.com/27414
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>
2016-08-21 22:17:24 +00:00