Commit graph

287 commits

Author SHA1 Message Date
Clément Chigot
3cf89e509b cmd/link: enable DWARF with external linker on aix/ppc64
In order to allow DWARF with ld, the symbol table is adapted.
In internal linkmode, each package is considered as a .FILE. However,
current version of ld is crashing on a few programs because of
relocations between DWARF symbols. Considering all packages as part of
one .FILE seems to bypass this bug.
As it might be fixed in a future release, the size of each package
in DWARF sections is still retrieved and can be used when it's fixed.
Moreover, it's improving internal linkmode which should have done it
anyway.

Change-Id: If3d023fe118b24b9f0f46d201a4849eee8d5e333
Reviewed-on: https://go-review.googlesource.com/c/go/+/164006
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-03-09 00:25:11 +00:00
Clément Chigot
f0749c74fd cmd/link: fix moduledata symbols for aix/ppc64 and external linking
Moduledata symbols like runtime.data or runtime.text must have the
same position in the final executable (as some symbol accesses are made
by offset from them).
ld on AIX might move them randomly if there are nil size symbols.

ld will also remove unreachable symbols like runtime.epclntab or
runtime.rodata. In order to keep them, R_REF relocations are created
between firstmoduledata and these symbols. This relocation tells ld to
keep these symbols even if there aren't reachable.

Change-Id: Ie5a28cf406977131cec6442f7f5b6fd89fb775a3
Reviewed-on: https://go-review.googlesource.com/c/go/+/164004
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-03-06 15:56:41 +00:00
Clément Chigot
80f10965ee cmd/link, runtime: allow external linking for aix/ppc64
This commit adds external linking in cmd/link for aix/ppc64.
As relocations on .text data aren't possible on AIX, Segrelrodata is
used to move all these datas to .data section.

Change-Id: I4d1361c1fc9290e11e6f5560864460c76551dbeb
Reviewed-on: https://go-review.googlesource.com/c/go/+/164003
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-03-06 15:32:25 +00:00
Clément Chigot
d3631955d4 cmd/link: set correct sizes for XCOFF outer symbols
This commit fixes the size of outer symbols like type.*.
Outer symbols cannot have a nil size on AIX or they will be
removed by ld as long as all their sub-symbols.

Change-Id: I68ff3ce5a3a034e3c3eb23431aba31245073cf20
Reviewed-on: https://go-review.googlesource.com/c/163999
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-02-27 23:24:03 +00:00
Clément Chigot
2deda8792a cmd/link: improve XCOFF symbol table
This commit improves symbol table for XCOFF format.
It adds symbol alignment, TLS symbols and move the whole symbol table at
the end of the FILE. As relocations in the future external linking will
need symbols' index, we cannot write the symbol table when it's
generated.

Change-Id: I5dcae85b95e538b65f1a128faf56d4e2aa15baf1
Reviewed-on: https://go-review.googlesource.com/c/163998
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-02-27 22:49:58 +00:00
Clément Chigot
9f9c5fa8c7 cmd/link: fix -a with external linker
This commit fixes a panic when -a was used with external linkmode.

Fixes #29807

Change-Id: I8cd42775f2953cec620cbc9ab345421c2694c9a2
Reviewed-on: https://go-review.googlesource.com/c/158998
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2019-02-27 21:41:32 +00:00
Clément Chigot
9a3c1a1bc8 cmd/link: move XCOFF data addresses to an unreachable segment
This commit move data addresses to 0x200000000 for XCOFF executables.
.data and .bss must always be position-independent on AIX. This
modification allows to detect more easily if they aren't, as segfault
will be triggered.

Change-Id: Ied7a5b72b9f4ff9f870a1626cf07c48110635e62
Reviewed-on: https://go-review.googlesource.com/c/151040
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-12-17 23:03:47 +00:00
Ian Lance Taylor
a11aa2aaec cmd/link: only create .init_array section if not empty
This avoids a warning from old versions of the GNU linker or glibc.

No test because these old versions are not readily available.
I tested this by hand on CentOS 6.

Fixes #28722

Change-Id: I16640c9b83a79f759ec68fac64874803e74fbbfb
Reviewed-on: https://go-review.googlesource.com/c/153257
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-12-11 03:31:35 +00:00
Tobias Klauser
9e277f7d55 all: use "reports whether" consistently instead of "returns whether"
Follow-up for CL 147037 and after Brad noticed the "returns whether"
pattern during the review of CL 150621.

Go documentation style for boolean funcs is to say:

    // Foo reports whether ...
    func Foo() bool

(rather than "returns whether")

Created with:

    $ perl -i -npe 's/returns whether/reports whether/' $(git grep -l "returns whether" | grep -v vendor)

Change-Id: I15fe9ff99180ad97750cd05a10eceafdb12dc0b4
Reviewed-on: https://go-review.googlesource.com/c/150918
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-12-02 15:12:26 +00:00
Clément Chigot
4295ed9bef cmd: fix symbols addressing for aix/ppc64
This commit changes the code generated for addressing symbols on AIX
operating system.

On AIX, every symbol accesses must be done via another symbol near the TOC,
named TOC anchor or TOC entry. This TOC anchor is a pointer to the symbol
address.
During Progedit function, when a symbol access is detected, its instructions
are modified to create a load on its TOC anchor and retrieve the symbol.

Change-Id: I00cf8f49c13004bc99fa8af13d549a709320f797
Reviewed-on: https://go-review.googlesource.com/c/151039
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-11-27 21:06:16 +00:00
Clément Chigot
b41cdc4a59 cmd/link: improve XCOFF dynamic symbols generation
This commit fixes and improves the generation of dynamic symbols for
XCOFF files.
This mainly adds for every dynamic symbols a new symbol named
s.Extname().

Change-Id: I5b788f076d9a05e5d42f08eb1a74fd3e3efa9a86
Reviewed-on: https://go-review.googlesource.com/c/151038
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-11-27 19:47:09 +00:00
Clément Chigot
3f9efe7500 cmd/link: fix XCOFF sections
XCOFF files can't have multiples text or data sections. The name
of each type section must be .text, .data and .bss.

This commit also updates cmd/internal/objfile/xcoff.go to retrieve Go
sections using runtime symbols.

Change-Id: Ib6315f19dad2d154a4531fc6508e7cbd8bc94743
Reviewed-on: https://go-review.googlesource.com/c/151037
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-11-26 23:51:21 +00:00
Clément Chigot
63ac89bfb1 cmd/link/internal/ld: remove R_ADDR relocations inside XCOFF text sections
On XCOFF, it is forbidden relocation of a DATA pointer to a text
section. It happens when a RODATA symbol needs a DATA symbol's address.
This commit moves every RODATA symbols with a R_ADDR on a data symbol to
.data sections to avoid these relocations.

Change-Id: I7f34d8e0ebdc8352a74e6b40e4c893d8d9419f4d
Reviewed-on: https://go-review.googlesource.com/c/146977
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-11-26 23:37:00 +00:00
Clément Chigot
269e531917 cmd/link: add AIX operating system
This commit adds AIX operating system to cmd/link package for ppc64
architecture.

Updates: #25893

Change-Id: I349e0a2658c31919b72117b62c4c9935c9af07c0
Reviewed-on: https://go-review.googlesource.com/c/138730
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-10-24 14:01:40 +00:00
Alex Brainman
8256bcdae0 cmd/link: move .rel symbol from .rdata into .text
.rel symbol type is sym.SELFROSECT, and that makes .rel written
into .rdata section. But .rel stores code - jump table used for
external C functions. So we have to mark whole .rdata section
as executable (IMAGE_SCN_MEM_EXECUTE), because of .rel presence
in it.

Move .rel into .text section, and make .rdata section non executable.

I also had to move code that adjusted the size of .rel symbol
before calling textaddress, otherwise textaddress would not
calculate size of .text section correctly.

Fixes #25926

Change-Id: I4962f5de7b367410154c8709adfcd8472de9ac1a
Reviewed-on: https://go-review.googlesource.com/c/125455
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-10-05 08:54:24 +00:00
Alessandro Arzilli
9c833831b2 cmd/link: move dwarf part of DWARF generation before type name mangling
Splits part of dwarfgeneratedebugsyms into a new function,
dwarfGenerateDebugInfo which is called between deadcode elimination
and type name mangling.
This function takes care of collecting and processing the DIEs for
all functions and package-level variables and also generates DIEs
for all types used in the program.

Fixes #23733

Change-Id: I75ef0608fbed2dffc3be7a477f1b03e7e740ec61
Reviewed-on: https://go-review.googlesource.com/111237
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
2018-09-04 17:44:41 +00:00
Than McIntosh
f78cc1324a cmd/link: move Plt, Got fields in sym.Symbol to cold section
The sym.Symbol 'Plt' and 'Got' field are used only with cgo and/or
external linking and are not needed for most symbols. Relocate them to
sym.AuxSymbol so as to shrink the main Symbol struct.

Updates #26186

Change-Id: I170d628a760be300a0c1f738f0998970e91ce3d6
Reviewed-on: https://go-review.googlesource.com/125478
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-08-30 12:35:10 +00:00
Than McIntosh
c7271c0c25 cmd/link: improve comments for relocsym
This patch contains the remnants of CL (122482), which was intended to
reduce memory allocation in 'relocsym'. Another CL (113637) went in
first that included pretty much all of the code changes in 122482,
however there are some changes to comments that are worth preserving.

Change-Id: Iacdbd2bfe3b7ca2656596570f06ce9a646211913
Reviewed-on: https://go-review.googlesource.com/122482
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-08-28 16:55:11 +00:00
Than McIntosh
422151ad50 cmd/link: fix a few typos in comments
Comment changes to fix typos, no code changes.

Change-Id: I6c915f183025587fc479d14f5d2c885767348b1b
Reviewed-on: https://go-review.googlesource.com/131615
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-08-28 15:33:37 +00:00
Jordan Rhee
aa311fecda cmd/link: support windows/arm
Enable the Go linker to generate executables for windows/arm.

Generates PE relocation tables, which are used by Windows to
dynamically relocate the Go binary in memory. Windows on ARM
requires all modules to be relocatable, unlike x86/amd64 which are
permitted to have fixed base addresses.

Updates #26148

Change-Id: Ie63964ff52c2377e121b2885e9d05ec3ed8dc1cd
Reviewed-on: https://go-review.googlesource.com/125648
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-08-21 22:11:05 +00:00
isharipo
bc276c585b cmd/link/internal/ld: avoid Reloc copies in range loops
Copying sym.Reloc in loops hurts performance as
it has 48 byte size (on 64-bit platforms).

There are quite many symbols and each of them has more than 1
relocation (so, it's possible to have more than 1kk relocs).
The're also traversed more than once in some code paths.

By using pointers to them, copies are avoided.

For linking "hello world" example from net/http:

	name      old time/op  new time/op  delta
	Linker-4   530ms ± 2%   521ms ± 3%  -1.80%  (p=0.000 n=17+20)

Change-Id: I6518aec69d6adcd137f84b5c089ceab4cb4ea2dd
Reviewed-on: https://go-review.googlesource.com/113636
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-08-21 02:29:51 +00:00
isharipo
328adf9d62 cmd/link: fewer allocs in ld.Arch.Archreloc
Archreloc had this signature:

	func(*Link, *sym.Reloc, *sym.Symbol, *int64) bool

The last *int64 argument is used as out parameter.
Passed valus could be allocated on stack, but escape analysis
fails here, leading to high number of unwanted allocs.

If instead 4th arg is passed by value, and modified values is returned,
no problems with allocations arise:

	func(*Link, *sym.Reloc, *sym.Symbol, int64) (int64, bool)

There are 2 benefits:
1. code becomes more readable.
2. less allocations.

For linking "hello world" example from net/http:

	name      old time/op  new time/op  delta
	Linker-4   530ms ± 2%   520ms ± 2%  -1.83%  (p=0.001 n=17+16)

It's top 1 in alloc_objects from memprofile:

	flat   flat%  sum%       cum    cum%
	229379 33.05% 33.05%     229379 33.05%  cmd/link/internal/ld.relocsym
	...

list relocsym:

	229379     229379 (flat, cum) 33.05% of Total
	229379     229379    183:    var o int64

After the patch, ~230k of int64 allocs (~ 1.75mb) removed.

Passes toolshash-check (toolstash cmp).

Change-Id: I25504fe27967bcff70c4b7338790f3921d15473d
Reviewed-on: https://go-review.googlesource.com/113637
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-08-20 22:10:31 +00:00
Austin Clements
12ed0ddec1 cmd/link: use BestSpeed for DWARF compression
DWARF compression accounts for roughly 30% of the linker's time. This
CL switches from DefaultCompression to BestSpeed, which virtually
eliminates this time. This roughly halves the overhead of handling
DWARF in the linker:

name \ time/op         nodwarf     dwarf        dwarf-speed
BuildCmdGoAll          10.0s ±11%   10.6s ± 5%   10.8s ± 5%
             nodwarf                  +6.41%       +8.03%
               dwarf                                 ~
LinkCmdGo              626ms ± 5%  1096ms ± 2%   860ms ± 2%
             nodwarf                 +75.17%      +37.36%
               dwarf                              -21.59%

Previously, enabling DWARF had a 75% overhead in link time for cmd/go.
This change reduces this overhead to 37% (a 22% reduction).

The effect on binary size is minimal compared to DefaultCompression,
and still substantially better than no compression:

             cmd/go bytes
nodwarf      10106953
dwarf        12159049 nodwarf+20%
dwarf-speed  12408905 nodwarf+23%
dwarf-nozlib 17766473 nodwarf+76%

Updates #26318.

Change-Id: I33bb7caa038a2753c29104501663daf4839e7054
Reviewed-on: https://go-review.googlesource.com/123356
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
2018-07-11 20:23:02 +00:00
LE Manh Cuong
6dd789fdea cmd/link: document limitation of -X
Fixes #26042

Change-Id: Ica16f14a65c03659a19926852cca5e554c99baf1
Reviewed-on: https://go-review.googlesource.com/120935
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-06-27 04:29:51 +00:00
Heschi Kreinick
594eae5ad0 cmd/link: compress DWARF sections in ELF binaries
Forked from CL 111895.

The trickiest part of this is that the binary layout code (blk,
elfshbits, and various other things) assumes a constant offset between
symbols' and sections' file locations and their virtual addresses.
Compression, of course, breaks this constant offset. But we need to
assign virtual addresses to everything before compression in order to
resolve relocations before compression. As a result, compression needs
to re-compute the "address" of the DWARF sections and symbols based on
their compressed size. Luckily, these are at the end of the file, so
this doesn't perturb any other sections or symbols. (And there is, of
course, a surprising amount of code that assumes the DWARF segment
comes last, so what's one more place?)

Relevant benchmarks:
name        old time/op     new time/op     delta
StdCmd          10.3s ± 2%      10.8s ± 1%   +5.43%  (p=0.000 n=30+30)

name        old text-bytes  new text-bytes  delta
HelloSize       746kB ± 0%      746kB ± 0%     ~     (all equal)
CmdGoSize      8.41MB ± 0%     8.41MB ± 0%     ~     (all equal)
[Geo mean]     2.50MB          2.50MB        +0.00%

name        old data-bytes  new data-bytes  delta
HelloSize      10.6kB ± 0%     10.6kB ± 0%     ~     (all equal)
CmdGoSize       252kB ± 0%      252kB ± 0%     ~     (all equal)
[Geo mean]     51.5kB          51.5kB        +0.00%

name        old bss-bytes   new bss-bytes   delta
HelloSize       125kB ± 0%      125kB ± 0%     ~     (all equal)
CmdGoSize       145kB ± 0%      145kB ± 0%     ~     (all equal)
[Geo mean]      135kB           135kB        +0.00%

name        old exe-bytes   new exe-bytes   delta
HelloSize      1.60MB ± 0%     1.05MB ± 0%  -34.39%  (p=0.000 n=30+30)
CmdGoSize      16.5MB ± 0%     11.3MB ± 0%  -31.76%  (p=0.000 n=30+30)
[Geo mean]     5.14MB          3.44MB       -33.08%

Fixes #11799.
Updates #6853.

Change-Id: I64197afe4c01a237523a943088051ee056331c6f
Reviewed-on: https://go-review.googlesource.com/118276
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-06-15 20:01:53 +00:00
Austin Clements
8998c55ec0 cmd/link: separate virtual address layout from file layout
Currently these two forms of layout are done in a single pass. This
makes it difficult to compress DWARF sections because that must be
done after relocations are applied, which must happen after virtual
address layout, but we can't layout the file until we've compressed
the DWARF sections.

Fix this by separating the two layout steps. In the process, we can
also unify the copy-pasted code in Link.address to compute file
offsets, which currently has some unnecessary variation.

Unlike the current file offset computation, which depends on virtual
addresses, the new computation only uses file offsets and sizes. This
will let us compress the file representation of a segment and create
the file layout based on its on-disk size rather than its original
in-memory size.

Tested by comparing the test binary for the "strings" package on all
supported GOOS/GOARCH combinations. All binaries are identical
(except, of course, their build IDs).

This is a second attempt at CL 111682.

For #11799.
Fixes #25863.

Change-Id: If09f28771bb4d78dd392fd58b8d7c9d5f22b0b9e
Reviewed-on: https://go-review.googlesource.com/118716
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-06-15 02:01:04 +00:00
Austin Clements
a1b85ee754 Revert "cmd/link: separate virtual address layout from file layout"
This reverts commit bd83774593.

Reason for revert: This broke ELF layout on arm, arm64, mips*, mips64*, ppc64*, and s390x.

Change-Id: I56a27b76e6f4b22ce39a99790af9116f8687eee9
Reviewed-on: https://go-review.googlesource.com/118675
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-06-13 17:55:32 +00:00
Austin Clements
bd83774593 cmd/link: separate virtual address layout from file layout
Currently these two forms of layout are done in a single pass. This
makes it difficult to compress DWARF sections because that must be
done after relocations are applied, which must happen after virtual
address layout, but we can't layout the file until we've compressed
the DWARF sections.

Fix this by separating the two layout steps. In the process, we can
also unify the copy-pasted code in Link.address to compute file
offsets. Currently, each instance of this is slightly different, but
there's no reason for it to be. For example, we don't perform
PEFILEALIGN alignment on Segrodata or Selreltodata even when HeadType
== Hwindows, but it turns out it doesn't matter whether you do or
don't because these segments simply don't exist on Windows. Hence, in
the unified code path, we do this alignment for all segments.
Likewise, there are two ways of computing Fileoff:
  seg.Vaddr - prev.Vaddr + prev.Fileoff
and
  prev.Fileoff + uint64(Rnd(int64(prev.Filelen), int64(*FlagRound)))
At the moment, these always have the same value, but the latter will
continue to work after we start compressing sections on disk.

Tested by comparing test binaries for all packages in std before and
after this change for GOOS={linux,windows,darwin,plan9}. All binaries
are identical.

For #11799.

Change-Id: If09f28771bb4d78dd392fd58b8d7c9d5f22b0b9f
Reviewed-on: https://go-review.googlesource.com/111682
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-06-12 20:37:02 +00:00
Alex Brainman
d67db88146 cmd/link: split pe .text section into .text and .rdata
Fixes #24725

Change-Id: I2864b88315ab15be036e8940d0a5884d876698d6
Reviewed-on: https://go-review.googlesource.com/115975
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-06-09 07:34:45 +00:00
Iskander Sharipov
289ab30457 cmd/link: fix duplicated "unresolved inter-package jump" errors
This is extension to https://golang.org/cl/113955 that handled
duplicated "unresolved relocation" errors.

For platforms with trampoline support, additional error is generated
per each undefined symbol. This breaks TestUndefinedRelocErrors test
on these platforms.

Proposed fix:

	1. Changes error text to be identical to normal undefined reloc.
	   If relocation is undefined, jump to it will be unresolved
	   as well.

	2. Introduces a map that can be used by all sites that
	   handle this kind of errors which makes it easier
	   to report such errors exactly once.

Errors on ppc64 before this change (note first 4 lines):

	main.defined1: unresolved inter-package jump to main.undefined()
	main.defined1: unresolved inter-package jump to main.undefined()
	main.defined2: unresolved inter-package jump to main.undefined()
	main.defined2: unresolved inter-package jump to main.undefined()
	main.defined1: relocation target main.undefined not defined
	main.defined2: relocation target main.undefined not defined
	runtime.main_main·f: function main is undeclared in the main package

After this change:

	main.defined1: relocation target main.undefined not defined
	main.defined2: relocation target main.undefined not defined
	runtime.main_main·f: function main is undeclared in the main package

Because of (1), errors output is the same on all platforms now.

Fixes #25753

Change-Id: Ic3084202a6fc5d4a6d2d0a93344f012b37fe58ed
Reviewed-on: https://go-review.googlesource.com/116676
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-06-08 21:32:33 +00:00
isharipo
2c01b7d632 cmd/link: fix duplicated "undefined reloc" errors
For given program with 2 undefined relocations (main and undefined):

	package main
	func undefined()
	func defined() int {
		undefined()
		undefined()
		return 0
	}
	var x = defined()

"go tool link" produces these errors:

	main.defined: relocation target main.undefined not defined
	main.defined: relocation target main.undefined not defined
	runtime.main_main·f: relocation target main.main not defined
	main.defined: undefined: "main.undefined"
	main.defined: undefined: "main.undefined"
	runtime.main_main·f: undefined: "main.main"

After this CL is applied:

	main.defined: relocation target main.undefined not defined
	runtime.main_main·f: function main is undeclared in the main package

Fixes #10978
Improved error message for main proposed in #24809.

Change-Id: I4ba8547b1e143bbebeb4d6e29ea05d932124f037
Reviewed-on: https://go-review.googlesource.com/113955
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-06-05 16:49:07 +00:00
Richard Musiol
f41dc711d8 cmd/link: add wasm architecture
This commit adds the wasm architecture to the link command.

Design doc: https://docs.google.com/document/d/131vjr4DH6JFnb-blm_uRdaC0_Nv3OUwjEY5qVCxCup4

Updates #18892

Change-Id: I5aef29954984537f2979679b5d393209e462f564
Reviewed-on: https://go-review.googlesource.com/103795
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2018-05-07 23:29:33 +00:00
Keith Randall
b7f1777a70 runtime,cmd/ld: on darwin, create theads using libc
Replace thread creation with calls to the pthread
library in libc.

Update #17490

Change-Id: I1e19965c45255deb849b059231252fc6a7861d6c
Reviewed-on: https://go-review.googlesource.com/108679
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-04-30 02:41:03 +00:00
Daniel Martí
a6b183fabd cmd/link/internal/ld: simple cleanups
Simplify some C-style loops with range statements, and move some
declarations closer to their uses.

While at it, ensure that all the SymbolType consts are typed.

Change-Id: I04b06afb2c1fb249ef8093a0c5cca0a597d1e05c
Reviewed-on: https://go-review.googlesource.com/105217
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-04-27 01:45:19 +00:00
Elias Naur
3363e98371 cmd/link: remove R_ADDR relocation workaround for macho arm64
The workarounds doesn't seem necessary anymore, and blocks DWARF
on darwin/arm64.

Updates #24883.

Change-Id: Ic917c767d3b4f6c51be25566956296f5dd4ead10
Reviewed-on: https://go-review.googlesource.com/108655
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2018-04-23 16:00:55 +00:00
Heschi Kreinick
393f84a125 cmd/ld: link to runtime types from DWARF
Add a new DWARF attribute, DW_AT_go_runtime_type, that gives the offset
of the runtime type structure, if any, for a DWARF type. This should
allow debuggers to decode interface content without having to do awkward
name matching.

Fixes #24814

Change-Id: Ic7a66524d2be484154c584afa9697111618efea4
Reviewed-on: https://go-review.googlesource.com/106775
Reviewed-by: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Reviewed-by: David Chase <drchase@google.com>
2018-04-20 19:51:37 +00:00
quasilyte
da02dcda02 cmd/link/internal/ld: make Thearch unexported
s/Thearch/thearch/

This reduces the amount of exported global variables,
which in turn could make it easier to refactor them later.

Also updated somewhat vague comment about ld.Thearch.
There is no need for Thearch to be exported as Archinit is
called by ld.Main.

Updates #22095

Change-Id: I266b291f6eac0165f70c51964738206e066cea08
Reviewed-on: https://go-review.googlesource.com/103878
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-04-02 23:39:16 +00:00
Keith Randall
403ab0f221 internal/bytealg: move IndexByte asssembly to the new bytealg package
Move the IndexByte function from the runtime to a new bytealg package.
The new package will eventually hold all the optimized assembly for
groveling through byte slices and strings. It seems a better home for
this code than randomly keeping it in runtime.

Once this is in, the next step is to move the other functions
(Compare, Equal, ...).

Update #19792

This change seems complicated enough that we might just declare
"not worth it" and abandon.  Opinions welcome.

The core assembly is all unchanged, except minor modifications where
the code reads cpu feature bits.

The wrapper functions have been cleaned up as they are now actually
checked by vet.

Change-Id: I9fa75bee5d85db3a65b3fd3b7997e60367523796
Reviewed-on: https://go-review.googlesource.com/98016
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-03-02 22:46:15 +00:00
Kunpei Sakai
0c471dfae2 cmd: avoid unnecessary type conversions
CL generated mechanically with github.com/mdempsky/unconvert.

Also updated cmd/compile/internal/ssa/gen/*.rules manually.

Change-Id: If721ef73cf0771ae83ce7e2d11623fc8d9155768
Reviewed-on: https://go-review.googlesource.com/97075
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-02-26 20:22:06 +00:00
Russ Cox
28639df158 cmd/link: apply -X options after loading symbols
The linker has been applying -X options before loading symbols,
meaning that when it sees -X y=z it creates a symbol named y
and initializes its string data to z. The symbol named y is marked
"DUPOK" so that when the actual packages are loaded, no error is
emitted when the real y is seen. The predefined y's data is used
instead of whatever the real y says.

If we define -X y=z and we never load y, then the predefined symbol
is dropped during dead code elimination, but not in shared library
builds. Shared library builds must include all symbols, so we have to
be more careful about not defining symbols that wouldn't have
appeared anyway.

To be more careful, save the -X settings until after all the symbols
are loaded from the packages, and then apply the string changes
to whatever symbols are known (but ignore the ones that were not
loaded at all). This ends up being simpler anyway, since it doesn't
depend on DUPOK magic.

Makes CL 86835 safe.

Fixes #23273.

Change-Id: Ib4c9b2d5eafa97c5a8114401dbec0134c76be54f
Reviewed-on: https://go-review.googlesource.com/86915
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-01-09 21:46:11 +00:00
Joe Tsai
b53088a634 Revert "go/printer: forbid empty line before first comment in block"
This reverts commit 08f19bbde1.

Reason for revert:
The changed transformation takes effect on a larger set
of code snippets than expected.

For example, this:
    func foo() {

        // Comment
        bar()

    }
becomes:
    func foo() {
        // Comment
        bar()

    }

This is an unintended consequence.

Change-Id: Ifca88d6267dab8a8170791f7205124712bf8ace8
Reviewed-on: https://go-review.googlesource.com/81335
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Joe Tsai <joetsai@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-12-01 01:12:26 +00:00
Jeff R. Allen
d7ac9bb992 cmd/compile: do not write slices/strings > 2g
The linker will refuse to work on objects larger than
2e9 bytes (see issue #9862 for why).

With this change, the compiler gives a useful error
message explaining this, instead of leaving it to the
linker to give a cryptic message later.

Fixes #1700.

Change-Id: I3933ce08ef846721ece7405bdba81dff644cb004
Reviewed-on: https://go-review.googlesource.com/74330
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-11-09 18:50:22 +00:00
Joe Tsai
08f19bbde1 go/printer: forbid empty line before first comment in block
To improve readability when exported fields are removed,
forbid the printer from emitting an empty line before the first comment
in a const, var, or type block.
Also, when printing the "Has filtered or unexported fields." message,
add an empty line before it to separate the message from the struct
or interfact contents.

Before the change:
<<<
type NamedArg struct {

        // Name is the name of the parameter placeholder.
        //
        // If empty, the ordinal position in the argument list will be
        // used.
        //
        // Name must omit any symbol prefix.
        Name string

        // Value is the value of the parameter.
        // It may be assigned the same value types as the query
        // arguments.
        Value interface{}
        // contains filtered or unexported fields
}
>>>

After the change:
<<<
type NamedArg struct {
        // Name is the name of the parameter placeholder.
        //
        // If empty, the ordinal position in the argument list will be
        // used.
        //
        // Name must omit any symbol prefix.
        Name string

        // Value is the value of the parameter.
        // It may be assigned the same value types as the query
        // arguments.
        Value interface{}

        // contains filtered or unexported fields
}
>>>

Fixes #18264

Change-Id: I9fe17ca39cf92fcdfea55064bd2eaa784ce48c88
Reviewed-on: https://go-review.googlesource.com/71990
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-11-02 18:17:22 +00:00
Alessandro Arzilli
018642d6cf compile, link: remove base address selector from DWARF range lists
Dsymutil, an utility used on macOS when externally linking executables,
does not support base address selector entries in debug_ranges.

To work around this deficiency this commit removes base address
selectors from debug_ranges and emits instead a list composed only of
compile unit relative addresses.

A new type of relocation is introduced, R_ADDRCUOFF, similar to
R_ADDROFF, that relocates an address to its offset from the low_pc of
the symbol's compile unit.

Fixes #21945

Change-Id: Ie991f9bc1afda2b49ac5d734eb41c37d3a37e554
Reviewed-on: https://go-review.googlesource.com/72371
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
2017-11-01 14:35:30 +00:00
Daniel Martí
7cb3e4fb1d all: unindent some if bodies by exiting early
All of these had a return or break in the else body, so flipping the
condition means we can unindent and simplify.

Change-Id: If93e97504480d18a0dac3f2c8ffe57ab8bcb929c
Reviewed-on: https://go-review.googlesource.com/74190
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-10-31 20:07:46 +00:00
Than McIntosh
b52b77cb95 cmd/compile, cmd/link: support for DWARF file reference relocations
New relocation flavor R_DWARFFILEREF, to be applied to DWARF attribute
values that correspond to file references (ex: DW_AT_decl_file,
DW_AT_call_file). The LSym for this relocation is the file itself; the
linker replaces the relocation target with the index of the specified
file in the line table's file section.

Note: for testing purposes this patch changes the DWARF function
subprogram DIE abbrev to include DW_AT_decl_file (allowed by DWARF
but not especially useful) so as to have a way to test this
functionality. This attribute will be removed once there are other
file reference attributes (coming as part of inlining support).

Change-Id: Icf676beb60fcc33f06d78e747ef717532daaa3ba
Reviewed-on: https://go-review.googlesource.com/73330
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2017-10-27 17:53:52 +00:00
David Crawshaw
6355d6c7e2 cmd/link, plugin: always encode path
Both the linker and the plugin package were inconsistent
about when they applied the path encoding defined in
objabi.PathToPrefix. As a result, only some symbols from
a package path that required encoding were being found.

So always encoding the path.

Fixes #22295

Change-Id: Ife86c79ca20b2e9307008ed83885e193d32b7dc4
Reviewed-on: https://go-review.googlesource.com/72390
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-10-26 15:08:37 +00:00
Michael Hudson-Doyle
1b8987f1a7 cmd/link: replace SSUB with an attribute bit
There is some stuff I don't understand very well involved in SSUB, better words
for the documentation gratefully accepted.

As this is the last use of a bit in SMASK, kill that off too.

Change-Id: Iddff1c9b2af02c9dfb12ac8e668d004e4642f997
Reviewed-on: https://go-review.googlesource.com/42026
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-10-24 23:06:28 +00:00
David Crawshaw
38cfeb9cb5 cmd/link: move Headtype global to ctxt
For #22095

Change-Id: Idcfdfe8a94db8626392658bb93429454238f648a
Reviewed-on: https://go-review.googlesource.com/70835
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-10-21 00:51:14 +00:00
David Crawshaw
d05f82a11a cmd/link: move Iself global to ctxt
For #22095

Change-Id: Iba3dffc782cecc15ea0e90a971a2734729984945
Reviewed-on: https://go-review.googlesource.com/70834
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-10-20 23:41:16 +00:00