While we're here, downgrade DWARF to version 2.
We're not using any version 3 features, and OS X gdb
only supports version 2.
Fixes#3436.
R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/7891044
Many thanks to Elias Naur for finding this with Valgrind on Linux.
Perhaps this is what is breaking the windows/amd64 builder.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7595044
lib9: fix runcmd, removeall, and tempdir functions
cmd/dist: Include run_plan9.c and tempdir_plan9.c
from lib9 for build, and in general consider
file names containing "plan9" for building.
cmd/ld: provide function args for the new functions
from lib9.
R=rsc, rminnich, ality, bradfitz
CC=golang-dev
https://golang.org/cl/7666043
The sticking point on 386 has been the "PC relative" relocations
used to point the garbage collection metadata at the type info.
These aren't in the code segment, and I don't trust that the linker
isn't doing something special that would be okay in code but
not when interpreting the pointers as data (for example, a PLT
jump table would be terrible).
Solve the problem in two steps:
1. Handle "PC relative" relocations within a section internally,
so that the external linker never sees them.
2. Move the gcdata and gcbss tables into the rodata section,
where the type information lives, so that the relocations can
be handled internally.
(To answer the obvious question, we make the gc->type
references relative so that they need not be relocated
individually when generating a shared object file.)
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7629043
- Introduce MaxAlign constant and use in data layout
and ELF section header.
- Allow up to 16-byte alignment for large objects
(will help Keith's hash changes).
- Emit ELF symbol for .rathole (global /dev/null used by 8c).
- Invoke gcc with -m32/-m64 as appropriate.
- Don't invoke gcc if writing the .o file failed.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7563045
Still to do: non-linux and non-amd64.
It may work on other ELF-based amd64 systems too, but untested.
"go test -ldflags -hostobj $GOROOT/misc/cgo/test" passes.
Much may yet change, but this seems a reasonable checkpoint.
R=iant
CC=golang-dev
https://golang.org/cl/7369057
This CL changes the encoding used for the Go symbol table,
stored in the binary and used at run time. It does not change
any of the semantics or structure: the bits are just packed
a little differently.
The comment at the top of runtime/symtab.c describes the new format.
Compared to the Go 1.0 format, the main changes are:
* Store symbol addresses as full-pointer-sized host-endian values.
(For 6g, this means addresses are 64-bit little-endian.)
* Store other values (frame sizes and so on) varint-encoded.
The second change more than compensates for the first:
for the godoc binary on OS X/amd64, the new symbol table
is 8% smaller than the old symbol table (1,425,668 down from 1,546,276).
This is a required step for allowing the host linker (gcc) to write
the final Go binary, since it will have to fill in the symbol address slots
(so the slots must be host-endian) and on 64-bit systems it may
choose addresses above 4 GB.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7403054
Previously, the func structure contained an inaccurate value for
the args member and a 0 value for the locals member.
This change populates the func structure with args and locals
values computed by the compiler. The number of args was
already available in the ATEXT instruction. The number of
locals is now passed through in the new ALOCALS instruction.
This change also switches the unit of args and locals to be
bytes, just like the frame member, instead of 32-bit words.
R=golang-dev, bradfitz, cshapiro, dave, rsc
CC=golang-dev
https://golang.org/cl/7399045
A step toward a fix for issue 4069.
To allow linking with arbitrary host object files, add a linker mode
that can generate a host object file instead of an executable.
Then the host linker can be invoked to generate the final executable.
This CL adds a new -hostobj flag that instructs the linker to write
a host object file instead of an executable.
That is, this works:
go tool 6g x.go
go tool 6l -hostobj -o x.o x.6
ld -e _rt0_amd64_linux x.o
./a.out
as does:
go tool 8g x.go
go tool 8l -hostld ignored -o x.o x.8
ld -m elf_i386 -e _rt0_386_linux x.o
./a.out
Because 5l was never updated to use the standard relocation scheme,
it will take more work to get this working on ARM.
This is a checkpoint of the basic functionality. It does not work
with cgo yet, and cgo is the main reason for the change.
The command-line interface will likely change too.
The gc linker has other information that needs to be returned to
the caller for use when invoking the host linker besides the single
object file.
R=iant, iant
CC=golang-dev
https://golang.org/cl/7060044
There's no b in race detector.
The new flag matches the one in the go command
(go test -race math).
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/7072043
This CL adds a flag parser that matches the semantics of Go's
package flag. It also changes the linkers and compilers to use
the new flag parser.
Command lines that used to work, like
8c -FVw
6c -Dfoo
5g -I/foo/bar
now need to be split into separate arguments:
8c -F -V -w
6c -D foo
5g -I /foo/bar
The new spacing will work with both old and new tools.
The new parser also allows = for arguments, as in
6c -D=foo
5g -I=/foo/bar
but that syntax will not work with the old tools.
In addition to matching standard Go binary flag parsing,
the new flag parser generates more detailed usage messages
and opens the door to long flag names.
The recently added gc flag -= has been renamed -complete.
R=remyoudompheng, daniel.morsing, minux.ma, iant
CC=golang-dev
https://golang.org/cl/7035043
More cleanup in preparation for fixing issue 4069.
This CL replaces the three nearly identical copies of the
asmb ELF code with a single asmbelf function in elf.c.
In addition to the ELF code movement, remove the elfstr
array in favor of a simpler lookup, and identify sections by
name throughout instead of computing fragile indices.
The CL also replaces the three nearly identical copies of the
genasmsym code with a single genasmsym function in lib.c.
The ARM linker still compiles and generates binaries,
but I haven't tested the binaries. They may not work.
R=ken2
CC=golang-dev
https://golang.org/cl/7062047
The 0-length part is fine, but some callers that write 0 bytes
also pass nil as the data pointer, and the Plan 9 kernel kills the
process with 'invalid address in sys call' in that case.
R=ken2
CC=golang-dev
https://golang.org/cl/6862051
This is the second part of a bigger change that adds data race detection feature:
https://golang.org/cl/6456044
This change makes the linker emit dependency on runtime/race package when supplied with -b flag.
R=rsc, minux.ma
CC=golang-dev
https://golang.org/cl/6488074
This fixes a problem with ELF tools thinking they know the
format of the symbol table, as we do not use any of the
standard formats for that table.
This change will probably annoy the Plan 9 users, but I
believe there are other incompatibilities already that mean
they have to use a Go-specific nm.
Fixes#3473.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/6500117
Introduce a newsym() to cmd/lib.c to add a symbol but don't add
them to hash table.
Introduce a new bit flag SHIDDEN and bit mask SMASK to handle hidden
and/or local symbols in ELF symbol tables. Though we still need to order
the symbol table entries correctly.
Fix for issue 3261 comment #9.
For CL 5822049.
R=iant, rsc
CC=golang-dev
https://golang.org/cl/5823055
This CL grew the archive file name length from 16 to 64:
changeset: 909:58574851d792
user: Russ Cox <rsc@golang.org>
date: Mon Oct 20 13:53:56 2008 -0700
Back then, every x.go file in a package became an x.6 file
in the archive. It was important to be able to allow the
use of long Go source file names, hence the increase in size.
Today, all Go source files compile into a single _go_.6 file
regardless of their names, so the archive file name length
no longer needs to be long. The longer name causes some
problems on Plan 9, where the native archive format is the
same but with 16-byte names, so revert back to 16.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5333050
The Go version has 64 character long section names; originally,
in Plan 9, the limit was 16. To provide compatibility, this
change allows the input length to be either the target length
or the earlier option. The section name is extended with spaces
where required.
This has been tested to work without regressions in the
Go environment, testing the older alternative has not been
possible yet.
R=rsc
CC=golang-dev
https://golang.org/cl/4650071
Reduces number of write+seek's from 88516 to 2080
when linking godoc with 6l.
Thanks to Alex Brainman for pointing out the
many small writes.
R=golang-dev, r, alex.brainman, robert.hencke
CC=golang-dev
https://golang.org/cl/4743043
The gosymtab and gopclntab sections were pointing to the proper
data, but that data was already owned by the rodata section.
Some ELF references explicitly prohibit multiple sections from
owning the same data, and strip behaves accordingly.
The data for these sections was moved to after rodata, and the
gosymtab and gopclntab sections now own their respective ranges.
This change makes strip happy both with and without -s being
provided at link time. Note that it won't remove these sections
because they are still allocated, and that's by design since
they are necessary at runtime for generating proper backtraces
and similar introspection operations.
Unlike the previous behavior, -s will now maintain zero-sized
gosymtab and gopclntab sections. This makes the implementation
slightly cleaner.
Fixes#1242.
NOTE: Tested on Linux amd64/386/arm only.
R=ality, rsc
CC=golang-dev
https://golang.org/cl/4639077
These changes are not particularly invasive and have been tested
as broadly as possible.
8l/l.h:
- #pragma varargck: added some, removed duplicates.
ld/dwarf.c:
- As Plan 9 has no NULL, changed all occurrences to nil.
- Added USED(size); where necessary.
- Added (void) argument in definition of finddebugruntimepath().
- Plan 9 compiler was complaining about multiple
assignments, repeaired by breaking up the commands.
- Correction: havedynamic = 1; restored.
ld/go.c:
- Needed USED(file); in two functions.
- Removed unused assignments flagged by the Plan 9 compiler.
ld/lib.c:
- Replaced unlink() with remove() which seems available everywhere.
- Removed USED(c4); and USED(magic) no longer required.
- Removed code flagged as unused by the Plan 9 compiler.
- Added attributes to a number of format strings.
R=rsc
CC=golang-dev
https://golang.org/cl/4435047
The ld time was dominated by symbol table processing, so
* increase hash table size
* emit fewer symbols in gc (just 1 per string, 1 per type)
* add read-only lookup to avoid creating spurious symbols
* add linked list to speed whole-table traversals
Breaks dwarf generator (no idea why), so disable dwarf.
Reduces time for 6l to link godoc by 25%.
R=ken2
CC=golang-dev
https://golang.org/cl/4383047
A reference to the address of weak.foo resolves at link time
to the address of the symbol foo if foo would end up in the
binary anyway, or to zero if foo would not be in the binary.
For example:
int xxx = 1;
int yyy = 2;
int weak·xxx;
int weak·yyy;
void main·main(void) {
runtime·printf("%p %p %p\n", &xxx, &weak·xxx, &weak·yyy);
}
prints the same non-nil address twice, then 0 (because yyy is not
referenced so it was dropped from the binary).
This will be used by the reflection tables.
R=iant
CC=golang-dev
https://golang.org/cl/4223044
Fix problems found.
On amd64, various library routines had bigger
stack frames than expected, because large function
calls had been added.
runtime.assertI2T: nosplit stack overflow
120 assumed on entry to runtime.assertI2T
8 after runtime.assertI2T uses 112
0 on entry to runtime.newTypeAssertionError
-8 on entry to runtime.morestack01
runtime.assertE2E: nosplit stack overflow
120 assumed on entry to runtime.assertE2E
16 after runtime.assertE2E uses 104
8 on entry to runtime.panic
0 on entry to runtime.morestack16
-8 after runtime.morestack16 uses 8
runtime.assertE2T: nosplit stack overflow
120 assumed on entry to runtime.assertE2T
16 after runtime.assertE2T uses 104
8 on entry to runtime.panic
0 on entry to runtime.morestack16
-8 after runtime.morestack16 uses 8
runtime.newselect: nosplit stack overflow
120 assumed on entry to runtime.newselect
56 after runtime.newselect uses 64
48 on entry to runtime.printf
8 after runtime.printf uses 40
0 on entry to vprintf
-8 on entry to runtime.morestack16
runtime.selectdefault: nosplit stack overflow
120 assumed on entry to runtime.selectdefault
56 after runtime.selectdefault uses 64
48 on entry to runtime.printf
8 after runtime.printf uses 40
0 on entry to vprintf
-8 on entry to runtime.morestack16
runtime.selectgo: nosplit stack overflow
120 assumed on entry to runtime.selectgo
0 after runtime.selectgo uses 120
-8 on entry to runtime.gosched
On arm, 5c was tagging functions NOSPLIT that should
not have been, like the recursive function printpanics:
printpanics: nosplit stack overflow
124 assumed on entry to printpanics
112 after printpanics uses 12
108 on entry to printpanics
96 after printpanics uses 12
92 on entry to printpanics
80 after printpanics uses 12
76 on entry to printpanics
64 after printpanics uses 12
60 on entry to printpanics
48 after printpanics uses 12
44 on entry to printpanics
32 after printpanics uses 12
28 on entry to printpanics
16 after printpanics uses 12
12 on entry to printpanics
0 after printpanics uses 12
-4 on entry to printpanics
R=r, r2
CC=golang-dev
https://golang.org/cl/4188061
Ian Lance Taylor
Rémy Oudompheng
Russ Cox
Akshat Kumar
Carl Shapiro
Elias Naur
Shenghou Ma
Dmitriy Vyukov
Christopher Nielsen
Scott Lawrence
Jaroslavas Počepko
Lucio De Re
Alex Brainman
Gustavo Niemeyer
Rob Pike
Luuk van Dijk