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>
CL 38662 changed the x86 assembler to be eagerly
initialized, for a concurrent backend.
This CL puts in place a proper mechanism for doing so,
and switches all architectures to use it.
Passes toolstash-check -all.
Updates #15756
Change-Id: Id2aa527d3a8259c95797d63a2f0d1123e3ca2a1c
Reviewed-on: https://go-review.googlesource.com/39917
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
In a concurrent backend, Ctxt.Lookup will need some
form of concurrency protection, which will make it
more expensive.
This CL changes the pcln table builder to track
filenames as strings rather than LSyms.
Those strings are then converted into LSyms
at the last moment, for writing the object file.
This CL removes over 85% of the calls to Ctxt.Lookup
in a run of make.bash.
Passes toolstash-check.
Updates #15756
Change-Id: I3c53deff6f16f2643169f3bdfcc7aca2ca58b0a4
Reviewed-on: https://go-review.googlesource.com/39291
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
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>
Remove the global obj.Link.Curp.
In asmz.go, replace the only use by passing it as an argument.
In asm0.go and asm9.go, it was written but never read.
In asm5.go and asm7.go, thread it through as an argument.
Passes toolstash-check -all.
Updates #15756
Change-Id: I1a0faa89e768820f35d73a8b37ec8088d78d15f7
Reviewed-on: https://go-review.googlesource.com/38715
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
These fields are used to encode a single instruction.
Add them to AsmBuf, which is also per-instruction,
and which is not global.
Updates #15756
Change-Id: I0e5ea22ffa641b07291e27de6e2ff23b6dc534bd
Reviewed-on: https://go-review.googlesource.com/38668
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The x86 assembler requires a buffer to build
variable-length instructions.
It used to be an obj.Link field.
That doesn't play nicely with concurrent assembly.
Move the AsmBuf type to the x86 package,
where it belongs anyway,
and make it a local variable.
Passes toolstash-check -all.
No compiler performance impact.
Updates #15756
Change-Id: I8014e52145380bfd378ee374a0c971ee5bada917
Reviewed-on: https://go-review.googlesource.com/38663
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Asmode is always set to p.Mode,
which is always set based on the arch family.
Instead, use the arch family directly.
Passes toolstash-check -all.
Change-Id: Id982472dcc8eeb6dd22cac5ad2f116b54a44caee
Reviewed-on: https://go-review.googlesource.com/38451
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Replace Ctxt.Mode with a method, Ctxt.RegWidth,
which is calculated directly off the arch info.
I believe that Prog.Mode can also be removed; future CL.
This is a step towards obj.Link immutability.
Passes toolstash-check -all.
Updates #15756
Change-Id: Ifd7f8f6ed0a2fdc032d1dd306fcd695a14aa5bc5
Reviewed-on: https://go-review.googlesource.com/38446
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Shrinks LSym somewhat for non-STEXT LSyms, which are much more common.
While here, switch to tracking Automs in a slice instead of a linked
list. (Previously, this would have made LSyms larger.)
Passes toolstash-check.
Change-Id: I082e50e1d1f1b544c9e06b6e412a186be6a4a2b5
Reviewed-on: https://go-review.googlesource.com/37872
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Change-Id: I6343c162e27e2e492547c96f1fc504909b1c03c0
Reviewed-on: https://go-review.googlesource.com/37793
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
For example, `-d pctab=pctoinline` prints the PC-inline table and
inlining tree for every function.
Change-Id: Ia6b9ce4d83eed0b494318d40ffe06481ec5d58ab
Reviewed-on: https://go-review.googlesource.com/37235
Run-TryBot: David Lazar <lazard@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
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>
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>
Link.Plists never contained more than one Plist, and sometimes none.
Passing around the Plist being worked on is straightforward and makes
the data flow easier to follow.
Change-Id: I79cb30cb2bd3d319fdbb1dfa5d35b27fcb748e5c
Reviewed-on: https://go-review.googlesource.com/37169
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
In cmd/compile, we can directly construct obj.Auto to represent local
variables and attach them to the function's obj.LSym.
In preparation for being able to emit more precise DWARF info based on
other compiler available information (e.g., lexical scoping).
Change-Id: I9c4225ec59306bec42552838493022e0e9d70228
Reviewed-on: https://go-review.googlesource.com/36420
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
XPos is a compact (8 instead of 16 bytes on a 64bit machine) source
position representation. There is a 1:1 correspondence between each
XPos and each regular Pos, translated via a global table.
In some sense this brings back the LineHist, though positions can
track line and column information; there is a O(1) translation
between the representations (no binary search), and the translation
is factored out.
The size increase with the prior change is brought down again and
the compiler speed is in line with the master repo (measured on
the same "quiet" machine as for prior change):
name old time/op new time/op delta
Template 256ms ± 1% 262ms ± 2% ~ (p=0.063 n=5+4)
Unicode 132ms ± 1% 135ms ± 2% ~ (p=0.063 n=5+4)
GoTypes 891ms ± 1% 871ms ± 1% -2.28% (p=0.016 n=5+4)
Compiler 3.84s ± 2% 3.89s ± 2% ~ (p=0.413 n=5+4)
MakeBash 47.1s ± 1% 46.2s ± 2% ~ (p=0.095 n=5+5)
name old user-ns/op new user-ns/op delta
Template 309M ± 1% 314M ± 2% ~ (p=0.111 n=5+4)
Unicode 165M ± 1% 172M ± 9% ~ (p=0.151 n=5+5)
GoTypes 1.14G ± 2% 1.12G ± 1% ~ (p=0.063 n=5+4)
Compiler 5.00G ± 1% 4.96G ± 1% ~ (p=0.286 n=5+4)
Change-Id: Icc570cc60ab014d8d9af6976f1f961ab8828cc47
Reviewed-on: https://go-review.googlesource.com/34506
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This replaces the src.Pos LineHist-based position tracking with
the syntax.Pos implementation and updates all uses.
The LineHist table is not used anymore - the respective code is still
there but should be removed eventually. CL forthcoming.
Passes toolstash -cmp when comparing to the master repo (with the
exception of a couple of swapped assembly instructions, likely due
to different instruction scheduling because the line-based sorting
has changed; though this is won't affect correctness).
The sizes of various important compiler data structures have increased
significantly (see the various sizes_test.go files); this is probably
the reason for an increase of compilation times (to be addressed). Here
are the results of compilebench -count 5, run on a "quiet" machine (no
apps running besides a terminal):
name old time/op new time/op delta
Template 256ms ± 1% 280ms ±15% +9.54% (p=0.008 n=5+5)
Unicode 132ms ± 1% 132ms ± 1% ~ (p=0.690 n=5+5)
GoTypes 891ms ± 1% 917ms ± 2% +2.88% (p=0.008 n=5+5)
Compiler 3.84s ± 2% 3.99s ± 2% +3.95% (p=0.016 n=5+5)
MakeBash 47.1s ± 1% 47.2s ± 2% ~ (p=0.841 n=5+5)
name old user-ns/op new user-ns/op delta
Template 309M ± 1% 326M ± 2% +5.18% (p=0.008 n=5+5)
Unicode 165M ± 1% 168M ± 4% ~ (p=0.421 n=5+5)
GoTypes 1.14G ± 2% 1.18G ± 1% +3.47% (p=0.008 n=5+5)
Compiler 5.00G ± 1% 5.16G ± 1% +3.12% (p=0.008 n=5+5)
Change-Id: I241c4246cdff627d7ecb95cac23060b38f9775ec
Reviewed-on: https://go-review.googlesource.com/34273
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This will let us use the src.Pos struct to thread inlining
information through to obj.
Change-Id: I96a16d3531167396988df66ae70f0b729049cc82
Reviewed-on: https://go-review.googlesource.com/34195
Run-TryBot: David Lazar <lazard@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
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>
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>
The Gotype field is only used for ATYPE instructions. Instead of
specially storing the Go type symbol in From.Gotype, just store it in
To.Sym like any other 2-argument instruction would.
Modest reduction in allocations:
name old alloc/op new alloc/op delta
Template 42.0MB ± 0% 41.8MB ± 0% -0.40% (p=0.000 n=9+10)
Unicode 34.3MB ± 0% 34.1MB ± 0% -0.48% (p=0.000 n=9+10)
GoTypes 122MB ± 0% 122MB ± 0% -0.14% (p=0.000 n=9+10)
Compiler 518MB ± 0% 518MB ± 0% -0.04% (p=0.000 n=9+10)
Passes toolstash -cmp.
Change-Id: I0e603266b5d7d4e405106a26369e22773a0d3a91
Reviewed-on: https://go-review.googlesource.com/31850
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
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>
Keep Plists in a slice instead of a linked list.
Eliminate unnecessary fields.
Also, while here remove gc's unused breakpc and continpc vars.
Change-Id: Ia04264036c0442843869965d247ccf68a5295115
Reviewed-on: https://go-review.googlesource.com/29367
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Replace the AGLOBL pseudo-op with a method to directly register an
LSym as a global. Similar to how we previously already replaced the
ADATA pseudo-op with directly writing out data bytes.
Passes toolstash -cmp.
Change-Id: I3631af0a2ab5798152d0c26b833dc309dbec5772
Reviewed-on: https://go-review.googlesource.com/29366
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Since the legacy backends were removed, these fields are write-only.
Change-Id: I4816c39267b7c10a4da2a6d22cd367dc475e564d
Reviewed-on: https://go-review.googlesource.com/29246
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Dave Cheney <dave@cheney.net>
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>
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>
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>
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>
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>
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>
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>
s390x took up the last available chunk of int16 opcodes.
There are RISC-V and sparc64 ports in progress out of tree,
and there will likely be other architectures.
Reduce the opcode space to allow more architectures to
fit without increasing to int32.
This is the smallest power of two that accomodates all
existing architectures. All else being equal, smaller is
better--smaller numbers are easier to generate immediates
for and easier on the eyes when debugging.
Change-Id: I4d0824b28913892fbd0579d3f90bea34e44c8946
Reviewed-on: https://go-review.googlesource.com/24223
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
This CL adds a safety mechanism
for changing the number of opcodes
available per architecture.
A subsequent CL will actually make the change.
Change-Id: I6332ed5514f2f153c54d11b7da0cc8a6be1c8066
Reviewed-on: https://go-review.googlesource.com/24222
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Add more ARM64 optimizations:
- use hardware zero register when it is possible.
- use shifted ops.
The assembler supports shifted ops but not documented, nor knows
how to print it. This CL adds them.
- enable fast division.
This was disabled because it makes the old backend generate slower
code. But with SSA it generates faster code.
Turn on SSA by default, also adjust tests.
Change-Id: I7794479954c83bb65008dcb457bc1e21d7496da6
Reviewed-on: https://go-review.googlesource.com/26950
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
This has a minor performance cost, but far less than is being gained by SSA.
As an experiment, enable it during the Go 1.7 beta.
Having frame pointers on by default makes Linux's perf, Intel VTune,
and other profilers much more useful, because it lets them gather a
stack trace efficiently on profiling events.
(It doesn't help us that much, since when we walk the stack we usually
need to look up PC-specific information as well.)
Fixes#15840.
Change-Id: I4efd38412a0de4a9c87b1b6e5d11c301e63f1a2a
Reviewed-on: https://go-review.googlesource.com/23451
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
a new relocation R_ADDRMIPSTLS is added, which resolves to 16-bit offset
of a TLS address on mips64x.
Change-Id: Ic60d0e1ba49ff1c433cead242f5884677ab227a5
Reviewed-on: https://go-review.googlesource.com/19804
Reviewed-by: Minux Ma <minux@golang.org>
SB register (R28) is introduced for access external addresses with shorter
instruction sequences. It is loaded at entry points. External data within
2G of SB can be accessed this way.
cmd/internal/obj: relocaltion R_ADDRMIPS is split into two relocations
R_ADDRMIPS and R_ADDRMIPSU, handling the low 16 bits and the "upper" 16
bits of external addresses, respectively, since the instructios may not
be adjacent. It might be better if relocation Variant could be used.
cmd/link/internal/mips64: support new relocations.
cmd/compile/internal/mips64: reserve SB register.
runtime: initialize SB register at entry points.
Change-Id: I5f34868f88c5a9698c042a8a1f12f76806c187b9
Reviewed-on: https://go-review.googlesource.com/19802
Reviewed-by: Minux Ma <minux@golang.org>
This CL introduces the typeOff type and a lookup method of the same
name that can turn a typeOff offset into an *rtype.
In a typical Go binary (built with buildmode=exe, pie, c-archive, or
c-shared), there is one moduledata and all typeOff values are offsets
relative to firstmoduledata.types. This makes computing the pointer
cheap in typical programs.
With buildmode=shared (and one day, buildmode=plugin) there are
multiple modules whose relative offset is determined at runtime.
We identify a type in the general case by the pair of the original
*rtype that references it and its typeOff value. We determine
the module from the original pointer, and then use the typeOff from
there to compute the final *rtype.
To ensure there is only one *rtype representing each type, the
runtime initializes a typemap for each module, using any identical
type from an earlier module when resolving that offset. This means
that types computed from an offset match the type mapped by the
pointer dynamic relocations.
A series of followup CLs will replace other *rtype values with typeOff
(and name/*string with nameOff).
For types created at runtime by reflect, type offsets are treated as
global IDs and reference into a reflect offset map kept by the runtime.
darwin/amd64:
cmd/go: -57KB (0.6%)
jujud: -557KB (0.8%)
linux/amd64 PIE:
cmd/go: -361KB (3.0%)
jujud: -3.5MB (4.2%)
For #6853.
Change-Id: Icf096fd884a0a0cb9f280f46f7a26c70a9006c96
Reviewed-on: https://go-review.googlesource.com/21285
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Only splits into separate files, no other changes.
Change-Id: Icc0da2c5f18e03e9ed7c0043bd7c790f741900f2
Reviewed-on: https://go-review.googlesource.com/21804
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This is the first in a series of CLs to replace the use of pointers
in binary read-only data with offsets.
In standard Go binaries these CLs have a small effect, shrinking
8-byte pointers to 4-bytes. In position-independent code, it also
saves the dynamic relocation for the pointer. This has a significant
effect on the binary size when building as PIE, c-archive, or
c-shared.
darwin/amd64:
cmd/go: -12KB (0.1%)
jujud: -82KB (0.1%)
linux/amd64 PIE:
cmd/go: -86KB (0.7%)
jujud: -569KB (0.7%)
For #6853.
Change-Id: Iad5625bbeba58dabfd4d334dbee3fcbfe04b2dcf
Reviewed-on: https://go-review.googlesource.com/21284
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
bio.BufReader was never used.
bio.BufWriter was used to wrap an existing io.Writer, but the
bio.Writer returned would not be seekable, so replace all occurences
with bufio.Reader instead.
Change-Id: I9c6779e35c63178aa4e104c17bb5bb8b52de0359
Reviewed-on: https://go-review.googlesource.com/21722
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Replace the bidirectional bio.Buf type with a pair of unidirectional
buffered seekable Reader and Writers.
Change-Id: I86664a06f93c94595dc67c2cbd21356feb6680ef
Reviewed-on: https://go-review.googlesource.com/21720
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
API could still be made more Go-ey.
Updates #15165.
Change-Id: I514ffceffa43c293ae5d7e5f1e9193fda0098865
Reviewed-on: https://go-review.googlesource.com/21644
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Information about CPU architectures (e.g., name, family, byte
ordering, pointer and register size) is currently redundantly
scattered around the source tree. Instead consolidate the basic
information into a single new package cmd/internal/sys.
Also, introduce new sys.I386, sys.AMD64, etc. names for the constants
'8', '6', etc. and replace most uses of the latter. The notable
exceptions are a couple of error messages that still refer to the old
char-based toolchain names and function reltype in cmd/link.
Passes toolstash/buildall.
Change-Id: I8a6f0cbd49577ec1672a98addebc45f767e36461
Reviewed-on: https://go-review.googlesource.com/21623
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This updates dwarf.go to generate debug information as symbols
instead of directly writing to the output file. This should make
it easier to move generation of some of the debug info into the compiler.
Change-Id: Id2358988bfb689865ab4d68f82716f0676336df4
Reviewed-on: https://go-review.googlesource.com/20679
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
We create appropriate ELF files automatically based on GOOS. There's
no point in supporting -H elf flag, particularly since we need to emit
different flavors of ELF depending on GOOS anyway.
If that weren't reason enough, -H elf appears to be broken since at
least Go 1.4. At least I wasn't able to find a way to make use of it.
As best I can tell digging through commit history, -H elf is just an
artifact leftover from Plan 9's 6l linker.
Change-Id: I7393caaadbc60107bbd6bc99b976a4f4fe6b5451
Reviewed-on: https://go-review.googlesource.com/21343
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
See #14874
This change tells the linker to collect all the itablink symbols and
collect them so that moduledata can have a slice of all compiler
generated itabs.
The logic is shamelessly adapted from what is done with typelink symbols.
Change-Id: Ie93b59acf0fcba908a876d506afbf796f222dbac
Reviewed-on: https://go-review.googlesource.com/20889
Reviewed-by: Keith Randall <khr@golang.org>
Adds a new R_PCRELDBL relocation for 2-byte aligned relative
relocations on s390x. Should be removed once #14218 is
implemented.
Change-Id: I79dd2d8e746ba8cbc26c570faccfdd691e8161e8
Reviewed-on: https://go-review.googlesource.com/20941
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This CL addresses a long standing CL by rsc by pushing the use of
Link.Windows down to its two users.
Link.Window was always initalised with the value of runtime.GOOS so
this does not affect cross compilation.
Change-Id: Ibbae068f8b5aad06336909691f094384caf12352
Reviewed-on: https://go-review.googlesource.com/20869
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
For every string constant the compiler was creating 2 Sym's and 2
Node's. It would never refer to them again, but would keep them alive
in gostringpkg. This changes the code to just use obj.LSym's instead.
When compiling x/tools/go/types, this yields about a 15% reduction in
the number of calls to newname and a 3% reduction in the total number of
Node objects. Unfortunately I couldn't see any change in compile time,
but reducing memory usage is desirable anyhow.
Passes toolstash -cmp.
Change-Id: I24f1cb1e6cff0a3afba4ca66f7166874917a036b
Reviewed-on: https://go-review.googlesource.com/20792
Reviewed-by: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
c2go translated writing and advancing a pointer using slices.
Switch to something more idiomatic.
It is also more efficient, but not enough to matter.
Change-Id: I67709632ac53253615a35365824ae97bbe5458d5
Reviewed-on: https://go-review.googlesource.com/20767
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Use a local variable instead.
Passes toolstash -cmp.
Change-Id: I9623a40ff0d568f11afd1279b6aaa1c33eda644c
Reviewed-on: https://go-review.googlesource.com/20730
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Symbols in the object file currently refer to each other using symbol name
and version. Referring to the same symbol many times in an object file takes
up space and causes redundant map lookups. Instead write out a list of unique
symbol references and have symbols refer to each other using indexes into this
list.
Credit to Michael Hudson-Doyle for kicking this off.
Reduces pkg/linux_amd64 size by 30% from 61MB to 43MB
name old s/op new s/op delta
LinkCmdGo 0.74 ± 3% 0.63 ± 4% -15.22% (p=0.000 n=20+20)
LinkJuju 6.38 ± 6% 5.73 ± 6% -10.16% (p=0.000 n=20+19)
Change-Id: I7e101a0c80b8e673a3ba688295e6f80ea04e1cfb
Reviewed-on: https://go-review.googlesource.com/20099
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Just recognize "DATA" as a special pseudo op word in the assembler
directly.
Change-Id: I508e111fd71f561efa600ad69567a7089a57adb2
Reviewed-on: https://go-review.googlesource.com/20648
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
The only remaining place that generated ADATA
Prog was the assembler. Stop, and delete some
now-dead code.
Passes toolstash -cmp.
Change-Id: I26578ff1b4868e98562b44f69d909c083e96f8d5
Reviewed-on: https://go-review.googlesource.com/20646
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
In addition to reflect.Value.Call, exported methods can be invoked
by the Func value in the reflect.Method struct. This CL has the
compiler track what functions get access to a legitimate reflect.Method
struct by looking for interface calls to either of:
Method(int) reflect.Method
MethodByName(string) (reflect.Method, bool)
This is a little overly conservative. If a user implements a type
with one of these methods without using the underlying calls on
reflect.Type, the linker will assume the worst and include all
exported methods. But it's cheap.
No change to any of the binary sizes reported in cl/20483.
For #14740
Change-Id: Ie17786395d0453ce0384d8b240ecb043b7726137
Reviewed-on: https://go-review.googlesource.com/20489
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Today the linker keeps all methods of reachable types. This is
necessary if a program uses reflect.Value.Call. But while use of
reflection is widespread in Go for encoders and decoders, using
it to call a method is rare.
This CL looks for the use of reflect.Value.Call in a program, and
if it is absent, adopts a (reasonably conservative) method pruning
strategy as part of dead code elimination. Any method that is
directly called is kept, and any method that matches a used
interface's method signature is kept.
Whether or not a method body is kept is determined by the relocation
from its receiver's *rtype to its *rtype. A small change in the
compiler marks these relocations as R_METHOD so they can be easily
collected and manipulated by the linker.
As a bonus, this technique removes the text segment of methods that
have been inlined. Looking at the output of building cmd/objdump with
-ldflags=-v=2 shows that inlined methods like
runtime.(*traceAllocBlockPtr).ptr are removed from the program.
Relatively little work is necessary to do this. Linking two
examples, jujud and cmd/objdump show no more than +2% link time.
Binaries that do not use reflect.Call.Value drop 4 - 20% in size:
addr2line: -793KB (18%)
asm: -346KB (8%)
cgo: -490KB (10%)
compile: -564KB (4%)
dist: -736KB (17%)
fix: -404KB (12%)
link: -328KB (7%)
nm: -827KB (19%)
objdump: -712KB (16%)
pack: -327KB (14%)
yacc: -350KB (10%)
Binaries that do use reflect.Call.Value see a modest size decrease
of 2 - 6% thanks to pruning of unexported methods:
api: -151KB (3%)
cover: -222KB (4%)
doc: -106KB (2.5%)
pprof: -314KB (3%)
trace: -357KB (4%)
vet: -187KB (2.7%)
jujud: -4.4MB (5.8%)
cmd/go: -384KB (3.4%)
The trivial Hello example program goes from 2MB to 1.68MB:
package main
import "fmt"
func main() {
fmt.Println("Hello, 世界")
}
Method pruning also helps when building small binaries with
"-ldflags=-s -w". The above program goes from 1.43MB to 1.2MB.
Unfortunately the linker can only tell if reflect.Value.Call has been
statically linked, not if it is dynamically used. And while use is
rare, it is linked into a very common standard library package,
text/template. The result is programs like cmd/go, which don't use
reflect.Value.Call, see limited benefit from this CL. If binary size
is important enough it may be possible to address this in future work.
For #6853.
Change-Id: Iabe90e210e813b08c3f8fd605f841f0458973396
Reviewed-on: https://go-review.googlesource.com/20483
Reviewed-by: Russ Cox <rsc@golang.org>
Deleting the string merging pass makes the linker 30-35% faster
but makes jujud (using the github.com/davecheney/benchjuju snapshot) 2.5% larger.
Two optimizations bring the space overhead down to 0.6%.
First, change the default alignment for string data to 1 byte.
(It was previously defaulting to larger amounts, usually pointer width.)
Second, write out the type string for T (usually a bigger expression) as "*T"[1:],
so that the type strings for T and *T share storage.
Combined, these obtain the bulk of the benefit of string merging
at essentially no cost. The remaining benefit from string merging
is not worth the excessive cost, so delete it.
As penance for making the jujud binary 0.6% larger,
the next CL in this sequence trims the reflect functype
information enough to make the jujud binary overall 0.75% smaller
(that is, that CL has a net -1.35% effect).
For #6853.
Fixes#14648.
Change-Id: I3fdd74c85410930c36bb66160ca4174ed540fc6e
Reviewed-on: https://go-review.googlesource.com/20334
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
No immediate reduction in the size of Addr.
Passes toolstash -cmp.
Change-Id: I78ea4c6e181b6e571ce70a5f1ae8158844eb197d
Reviewed-on: https://go-review.googlesource.com/20276
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.
This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:
$ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])')
$ go test go/doc -update
Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Simplifies some code as ptrToThis was unreliable under dynamic
linking. Now the same type lookup is used regardless of execution
mode.
A synthetic relocation, R_USETYPE, is introduced to make sure the
linker includes *T on use of T, if *T is carrying methods.
Changes the heap dump format. Anything reading the format needs to
look at the last bool of a type of an interface value to determine
if the type should be the pointer-to type.
Reduces binary size of cmd/go by 0.2%.
For #6853.
Change-Id: I79fcb19a97402bdb0193f3c7f6d94ddf061ee7b2
Reviewed-on: https://go-review.googlesource.com/19695
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
When -N, make sure we don't drop every instruction from
a block, even ones which would otherwise be empty.
Helps keep line numbers around for debugging, particularly
for break and continue statements (which often compile
down to nothing).
Fixes#14379
Change-Id: I33722c4f0dcd502f146fa48af262ba3a477c959a
Reviewed-on: https://go-review.googlesource.com/19854
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
Semi-regular merge from tip to dev.ssa.
Two fixes:
1) Mark selectgo as not returning. This caused problems
because there are no VARKILL ops on the selectgo path,
causing things to be marked live that shouldn't be.
2) Tell the amd64 assembler that addressing modes like
name(SP)(AX*4) are ok.
Change-Id: I9ca81c76391b1a65cc47edc8610c70ff1a621913
The x86 backend automatically rewrites MOV $0, AX to
XOR AX, AX. That rewrite isn't ok when the flags register
is live across the MOV. Keep track of which moves care
about preserving flags, then disable this rewrite for them.
On x86, Prog.Mark was being used to hold the length of the
instruction. We already store that in Prog.Isize, so no
need to store it in Prog.Mark also. This frees up Prog.Mark
to hold a bitmask on x86 just like all the other architectures.
Update #12405
Change-Id: Ibad8a8f41fc6222bec1e4904221887d3cc3ca029
Reviewed-on: https://go-review.googlesource.com/18861
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
Add test for assembly errors, to verify fix.
Make sure invalid instruction errors are printed just once
(was printing them once per span iteration, so typically twice).
Fixes#13282.
Change-Id: Id5f66f80a80b3bc4832e00084b0a91f1afec7f8f
Reviewed-on: https://go-review.googlesource.com/18858
Reviewed-by: Rob Pike <r@golang.org>
This will allow the compiler to crunch Prog lists down to code as each
function is compiled, instead of waiting until the end, which should
reduce the working set of the compiler. But not until Go 1.7.
This also makes it easier to write some machine code output tests
for the assembler, which is why it's being done now.
For #13822.
Change-Id: I0811123bc6e5717cebb8948f9cea18e1b9baf6f7
Reviewed-on: https://go-review.googlesource.com/18311
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Consider this code:
func f(*int)
func g() {
p := new(int)
f(p)
}
where f is an assembly function.
In general liveness analysis assumes that during the call to f, p is dead
in this frame. If f has retained p, p will be found alive in f's frame and keep
the new(int) from being garbage collected. This is all correct and works.
We use the Go func declaration for f to give the assembly function
liveness information (the arguments are assumed live for the entire call).
Now consider this code:
func h1() {
p := new(int)
syscall.Syscall(1, 2, 3, uintptr(unsafe.Pointer(p)))
}
Here syscall.Syscall is taking the place of f, but because its arguments
are uintptr, the liveness analysis and the garbage collector ignore them.
Since p is no longer live in h once the call starts, if the garbage collector
scans the stack while the system call is blocked, it will find no reference
to the new(int) and reclaim it. If the kernel is going to write to *p once
the call finishes, reclaiming the memory is a mistake.
We can't change the arguments or the liveness information for
syscall.Syscall itself, both for compatibility and because sometimes the
arguments really are integers, and the garbage collector will get quite upset
if it finds an integer where it expects a pointer. The problem is that
these arguments are fundamentally untyped.
The solution we have taken in the syscall package's wrappers in past
releases is to insert a call to a dummy function named "use", to make
it look like the argument is live during the call to syscall.Syscall:
func h2() {
p := new(int)
syscall.Syscall(1, 2, 3, uintptr(unsafe.Pointer(p)))
use(unsafe.Pointer(p))
}
Keeping p alive during the call means that if the garbage collector
scans the stack during the system call now, it will find the reference to p.
Unfortunately, this approach is not available to users outside syscall,
because 'use' is unexported, and people also have to realize they need
to use it and do so. There is much existing code using syscall.Syscall
without a 'use'-like function. That code will fail very occasionally in
mysterious ways (see #13372).
This CL fixes all that existing code by making the compiler do the right
thing automatically, without any code modifications. That is, it takes h1
above, which is incorrect code today, and makes it correct code.
Specifically, if the compiler sees a foreign func definition (one
without a body) that has uintptr arguments, it marks those arguments
as "unsafe uintptrs". If it later sees the function being called
with uintptr(unsafe.Pointer(x)) as an argument, it arranges to mark x
as having escaped, and it makes sure to hold x in a live temporary
variable until the call returns, so that the garbage collector cannot
reclaim whatever heap memory x points to.
For now I am leaving the explicit calls to use in package syscall,
but they can be removed early in a future cycle (likely Go 1.7).
The rule has no effect on escape analysis, only on liveness analysis.
Fixes#13372.
Change-Id: I2addb83f70d08db08c64d394f9d06ff0a063c500
Reviewed-on: https://go-review.googlesource.com/18584
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This requires changing the tls access code to match the patterns documented in
the ABI documentation or the system linker will "optimize" it into ridiculousness.
With this change, -buildmode=pie works, although as it is tested in testshared,
the tests are not run yet.
Change-Id: I1efa6687af0a5b8db3385b10f6542a49056b2eb3
Reviewed-on: https://go-review.googlesource.com/15971
Reviewed-by: Russ Cox <rsc@golang.org>
The PowerPC ISA does not have a PC-relative load instruction, which poses
obvious challenges when generating position-independent code. The way the ELFv2
ABI addresses this is to specify that r2 points to a per "module" (shared
library or executable) TOC pointer. Maintaining this pointer requires
cooperation between codegen and the system linker:
* Non-leaf functions leave space on the stack at r1+24 to save the TOC pointer.
* A call to a function that *might* have to go via a PLT stub must be followed
by a nop instruction that the system linker can replace with "ld r1, 24(r1)"
to restore the TOC pointer (only when dynamically linking Go code).
* When calling a function via a function pointer, the address of the function
must be in r12, and the first couple of instructions (the "global entry
point") of the called function use this to derive the address of the TOC
for the module it is in.
* When calling a function that is implemented in the same module, the system
linker adjusts the call to skip over the instructions mentioned above (the
"local entry point"), assuming that r2 is already correctly set.
So this changeset adds the global entry point instructions, sets the metadata so
the system linker knows where the local entry point is, inserts code to save the
TOC pointer at 24(r1), adds a nop after any call not known to be local and copes
with the odd non-local code transfer in the runtime (e.g. the stuff around
jmpdefer). It does not actually compile PIC yet.
Change-Id: I7522e22bdfd2f891745a900c60254fe9e372c854
Reviewed-on: https://go-review.googlesource.com/15967
Reviewed-by: Russ Cox <rsc@golang.org>
The larger stack frames causes the nosplit stack to overflow so the next change
increases the stackguard.
Change-Id: Ib2b4f24f0649eb1d13e3a58d265f13d1b6cc9bf9
Reviewed-on: https://go-review.googlesource.com/15964
Reviewed-by: Russ Cox <rsc@golang.org>
MIPS64 has 32 general purpose 64-bit integer registers (R0-R31), 32
64-bit floating point registers (F0-F31). Instructions are fixed-width,
and are 32-bit wide. Instructions are all in standard 1-, 2-, 3-operand
forms.
MIPS64-specific relocations are added. For this reason, test data of
cmd/newlink are regenerated.
No other changes are made to portable structures.
Branch delay slots are current filled with NOP instructions. The function
for instruction scheduling (try to fill the delay slot with a useful
instruction) is implemented but disabled for now.
Change-Id: Ic364999c7a33245260c1381fc26a2fa8972d38b3
Reviewed-on: https://go-review.googlesource.com/14442
Reviewed-by: Minux Ma <minux@golang.org>
On ppc64x, the thread pointer, held in R13, points 0x7000 bytes past where
thread-local storage begins (presumably to maximize the amount of storage that
can be accessed with a 16-bit signed displacement). The relocations used to
indicate thread-local storage to the platform linker account for this, so to be
able to support external linking we need to change things so the linker applies
this offset instead of the runtime assembly.
Change-Id: I2556c249ab2d802cae62c44b2b4c5b44787d7059
Reviewed-on: https://go-review.googlesource.com/14233
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Shared libraries on ppc64le will require a larger minimum stack frame (because
the ABI mandates that the TOC pointer is available at 24(R1)). Part 2a of
preparing for that is to have all bits of arch-independent and ppc64-specific
codegen that need to know call a function to find out.
Change-Id: I55899f73037e92227813c491049a3bd6f30bd41f
Reviewed-on: https://go-review.googlesource.com/15524
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Due to #9401, trailing empty fields will occupy at least 1 byte
of space.
Fixes#12884.
Change-Id: I838d3f1a73637e526f5a6dbc348981227d5bb2fd
Reviewed-on: https://go-review.googlesource.com/15660
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
obj.ProgInfo is a field inside obj.Prog, which is currently 320 bytes
on 64bit platforms. By moving the Flags field below the other fields
the size of obj.Prog drops into the 288 byte size class, a saving of
32 bytes per value allocated on the heap.
Change-Id: If8bb12f45328996d7df1d0bac9d1c019d2af73bd
Reviewed-on: https://go-review.googlesource.com/15522
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
It's particularly nice to get rid of the android special cases in the linker.
Change-Id: I516363af7ce8a6b2f196fe49cb8887ac787a6dad
Reviewed-on: https://go-review.googlesource.com/14197
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently Go produces shared libraries that cannot be shared between processes
because they have relocations against the text segment (not text section). This
fixes this by moving some data to sections with magic names recognized by the
static linker.
The change in genasmsym to add STYPELINK to the switch should fix things on
darwin/arm64.
Fixes#10914
Updates #9210
Change-Id: Iab4a6678dd04cec6114e683caac5cf31b1063309
Reviewed-on: https://go-review.googlesource.com/14306
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This reverts commit 2c2cbb69c8.
Broke darwin/arm64
Change-Id: Ibd2dea475d6ce6a8b4b40e2da19a83fc0514025d
Reviewed-on: https://go-review.googlesource.com/14301
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently Go produces shared libraries that cannot be shared between processes
because they have relocations against the text segment (not text section). This
fixes this by moving some data to sections with magic names recognized by the
static linker.
Fixes#10914
Updates #9210
Change-Id: I7178daadc0ae87953d5a084aa3d580f4e3b46d47
Reviewed-on: https://go-review.googlesource.com/10300
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Nothing uses it any more.
Change-Id: I42ee7222b06b1a79b8b44894f3071752f9166d7a
Reviewed-on: https://go-review.googlesource.com/14193
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Same as we do for string symbols.
Fixes#11583.
Change-Id: Ia9264f6faf486697d987051b7f9851d37d8ad381
Reviewed-on: https://go-review.googlesource.com/12531
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
It looks like the test for whether symbols contain subsymbols is wrong.
In particular, symbols in C libraries are mistakenly considered container
symbols.
Fix the test so only symbols which actually have a subsymbol
are excluded from the symtab. When linking cgo programs the list
of containers is small, something like:
container _/home/khr/sandbox/symtab/misc/cgo/test(.text)<74>
container _/home/khr/sandbox/symtab/misc/cgo/test/issue8828(.text)<75>
container _/home/khr/sandbox/symtab/misc/cgo/test/issue9026(.text)<76>
container runtime/cgo(.text)<77>
I'm not sure this is the right fix. In particular I can't reproduce
the original problem. Anyone have a repro they can try and see if
this fix works?
Fixes#10747Fixes#11396
Change-Id: Id8b016389d33348b4a791fdcba0f9db8ae71ebf3
Reviewed-on: https://go-review.googlesource.com/11652
Reviewed-by: Russ Cox <rsc@golang.org>
They're each architecture-specific.
Let them share.
Reduces Prog size to 288, which is the
next smaller malloc class.
Reduces inuse_space while compiling the
rotate tests by ~3.2%.
Change-Id: Ica8ec90e466c97b569745fffff0e5acd364e55fa
Reviewed-on: https://go-review.googlesource.com/10514
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
That which cannot happen has not happened.
No immediate changes to Addr or Prog size.
Change-Id: I4cb9315f2c9f5f92eda340bfc4abb46395fa467f
Reviewed-on: https://go-review.googlesource.com/10513
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Printed and Width were unused.
Despite only removing two bytes, due to alignment, 8 bytes are saved
on 64-bit:
Before: unsafe.Sizeof(obj.Prog{}) == 304
After: unsafe.Sizeof(obj.Prog{}) == 296
The next size class below 320 (304=>19(320)) is 288. Still 8 bytes
away from that.
Change-Id: I8d1632dd40d387f7036c03c65ea4d64e9b6218c3
Reviewed-on: https://go-review.googlesource.com/10511
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
It is almost never set and Addr is large, so having the full struct
in the Prog wastes memory most of the time.
Before (on a 64-bit system):
$ sizeof -p cmd/internal/obj Addr Prog
Addr 80
Prog 376
$
After:
$ sizeof -p cmd/internal/obj Addr Prog
Addr 80
Prog 304
$
Change-Id: I491f201241f87543964a7d0f48b85830759be9d0
Reviewed-on: https://go-review.googlesource.com/10457
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
It shrinks Prog type from 448 bytes down to 376 bytes on amd64.
It also makes sense, because I don't know of any modern architecture
that have instructions which can write to two destinations, none of
which is a register (even x86 doesn't have such instructions).
Change-Id: I3061f1c9ac93d79ee2b92ecb9049641d0e0f6300
Reviewed-on: https://go-review.googlesource.com/10330
Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Russ Cox <rsc@golang.org>
F3t was effectively a local variable.
Remove it.
This shrinks obj.Prog from 456 to 448 bytes,
which places it in a smaller malloc class.
This reduces the memory usage of the compiler
while compiling the rotate tests by ~2.75%.
Change-Id: I31cc9dd67269851a430b56bcc7d255c9349eb522
Reviewed-on: https://go-review.googlesource.com/10255
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This started out as trying to remove Bool2int calls, which it does a bit, but
mostly it ended up being removing the Link.Symmorestack array which seemed a
pointless bit of caching.
Change-Id: I91a51eb08cb4b08f3f9f093b575306499267b67a
Reviewed-on: https://go-review.googlesource.com/9239
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The long comment block in obj6.go:progedit talked about the two code sequences
for accessing g as "local exec" and "initial exec", but really they are both forms
of local exec. This stuff is confusing enough without using the wrong words for
things, so rewrite it to talk about 2-instruction and 1-instruction sequences.
Unfortunately the confusion has made it into code, with the R_TLS_IE relocation
now doing double duty as meaning actual initial exec when externally linking and
boring old local exec when linking internally (half of this is my fault). So this
stops using R_TLS_IE in the local exec case. There is a chance this might break
plan9 or windows, but I don't think so. Next step is working out what the heck is
going on on ARM...
Change-Id: I09da4388210cf49dbc99fd25f5172bbe517cee57
Reviewed-on: https://go-review.googlesource.com/9273
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
This lets us avoid loading string constants via the GOT and (together with
http://golang.org/cl/9102) results in the fannkuch benchmark having very similar
register usage with -dynlink as without.
Change-Id: Ic3892b399074982b76773c3e547cfbba5dabb6f9
Reviewed-on: https://go-review.googlesource.com/9103
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
They don't really make any sense on this side of the compiler/linker divide.
Some of the code touching these fields was the support for R_TLS when
thechar=='6' which turns out to be dead and so I just removed all of that.
Change-Id: I4e265613c4e7fcc30a965fffb7fd5f45017f06f3
Reviewed-on: https://go-review.googlesource.com/9107
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
http://golang.org/cl/7623 refactored how line history works and
introduced a new TrimPathPrefix field to replace the existing Trimpath
field, but never removed the latter or updated its users.
Fixes#10503.
Change-Id: Ief90a55b6cef2e8062b59856a4c7dcc0df01d3f2
Reviewed-on: https://go-review.googlesource.com/9113
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
This CL introduces R_ADDRARM64, which is similar to R_ADDRPOWER.
Fixes#10112.
Change-Id: I309e3df7608b9eef9339196fdc50dedf5f9439f1
Reviewed-on: https://go-review.googlesource.com/8438
Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
A quick pass through link.go, mostly removing fields that are not
used on the "creating a single object file" side of the fence.
Change-Id: I35ba41378c2c418f7df2f2f88dce65bc64a1a45d
Reviewed-on: https://go-review.googlesource.com/7672
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The ProgInfo is loaded many times during each analysis pass.
Load it once at the beginning (in Flowstart if using that, or explicitly,
as in plive.go) and then refer to the cached copy.
Removes many calls to proginfo.
Makes Prog a little bigger, but the previous CL more than compensates.
Change-Id: If90a12fc6729878fdae10444f9c3bedc8d85026e
Reviewed-on: https://go-review.googlesource.com/7745
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
An interface{} is more in the spirit of the original union.
By my calculations, on 64-bit systems this reduces
Addr from 120 to 80 bytes, and Prog from 592 to 424 bytes.
Change-Id: I0d7b0981513c2a3c94c9ac76bb4f8816485b5a3c
Reviewed-on: https://go-review.googlesource.com/7744
Reviewed-by: Rob Pike <r@golang.org>
I think the file ended up in the order of the typedefs instead of the
order of the actual struct definitions. You can see where some of
the declarations were because some of the comments didn't move.
Put things back in the original order.
Change-Id: I0e3703008278b084b632c917cfb73bc81bdd4f23
Reviewed-on: https://go-review.googlesource.com/7743
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
In addition to possibly being clearer code,
this replaces an O(n) lookup with an O(log n) lookup.
Change-Id: I0a574c536a965a87f7ad6dcdcc30f737bc771cd5
Reviewed-on: https://go-review.googlesource.com/7623
Reviewed-by: Rob Pike <r@golang.org>
ARM64 (ARMv8) has 32 general purpose, 64-bit integer registers
(R0-R31), 32 64-bit scalar floating point registers (F0-F31), and
32 128-bit vector registers (unused, V0-V31).
R31 is either the stack pointer (RSP), or the zero register (ZR),
depending on the instruction. Note the distinction between the
hardware stack pointer, RSP, and the virtual stack pointer SP.
The (hardware) stack pointer must be 16-byte aligned at all times;
the RSP register itself must be aligned, offset(RSP) only has to
have natural alignment.
Instructions are fixed-width, and are 32-bit wide. ARM64 supports
ARMv7 too (32-bit ARM), but not in the same process. In general,
there is not much in common between 32-bit ARM and ARM64, it's a
new architecture.
All implementations have floating point instructions.
This change adds a Prog.To3 field analogous to Prog.To. It is used
by exclusive load/store instructions such as STLXR which read from
one register, and write to both a register and a memory address.
STLXRW R1, (R0), R3
This will store the word contained in R1 to the memory address
pointed by R0. R3 will be updated with the status result of the
store. It is used to implement atomic operations.
No other changes are made to the portable Prog and Addr structures.
Change-Id: Ie839029aa5265bbad35769d9689eca11e1c48c47
Reviewed-on: https://go-review.googlesource.com/7046
Reviewed-by: Russ Cox <rsc@golang.org>
Alessandro Arzilli
Josh Bleecher Snyder
Alex Brainman
Matthew Dempsky
Eitan Adler
David Lazar
Heschi Kreinick
Cherry Zhang
Robert Griesemer
David Crawshaw
Vladimir Stefanovic
shaharko
Michael Pratt
Emmanuel Odeke
Dave Cheney
Keith Randall
Russ Cox
Cherry Zhang
Ryan Brown
Michel Lespinasse
Marvin Stenger
Michael Munday
Ian Lance Taylor
Brad Fitzpatrick
Michael Hudson-Doyle
Shenghou Ma
Ilya Tocar
Aram Hăvărneanu