326 Commits

Author SHA1 Message Date
Hiroshi Ioka
88a1e85c70 cmd/link: fix warning for buildmode=plugin on darwin/amd64
Without this CL, the system linker complains about absolute addressing
in type..eqfunc.*.

Updates #18190

Change-Id: I68db37a7f4c96b16a9c13baffc0f043a3048df6d
Reviewed-on: https://go-review.googlesource.com/59373
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-29 00:51:34 +00:00
Hiroshi Ioka
0c4d035ca8 cmd/link: refactor *reloc
* use bool instead of int if it's adequate.
* remove blank lines.

Change-Id: Ic4a5644a33ed9fc7ce388ef8ba15f1732446fcfc
Reviewed-on: https://go-review.googlesource.com/59375
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-28 05:42:48 +00:00
Hiroshi Ioka
6eef2bb5ee cmd/link: avoid leaking file in ldshlibsyms
Change-Id: If27f7fbf94ede6f9a57f2520aaf75e6506e0b3f8
Reviewed-on: https://go-review.googlesource.com/59374
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
2017-08-27 22:27:21 +00:00
Agniva De Sarker
ea5e3bd2a1 all: fix easy-to-miss typos
Using the wonderful https://github.com/client9/misspell tool.

Change-Id: Icdbc75a5559854f4a7a61b5271bcc7e3f99a1a24
Reviewed-on: https://go-review.googlesource.com/57851
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-23 03:07:12 +00:00
Hiroshi Ioka
064ae118c1 cmd/link: correct runtime/cgo detection for -linkshared
Current code detect runtime/cgo iff the package or sub packages imports
runtime/cgo directly. However, when we are using linkshared, imported
shared libraries might have already included runtime/cgo.
This CL handles later case by looking an actual runtime/cgo symbol.

Change-Id: I35e7dfdb5e1a939eafc95a0259ee1af9782bc864
Reviewed-on: https://go-review.googlesource.com/56310
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-17 01:12:30 +00:00
Hiroshi Ioka
b7c600d6ba cmd/go, cmd/link: enable buildmode=pie on darwin/amd64
Change some configurations to enable the feature. Also add the test.
This CL doesn't include internal linking support which is tentatively
disabled due to #18968. We could do that another day.

Fixes #21220

Change-Id: I601d2d78446d36332acc70be0d5b9461ac635208
Reviewed-on: https://go-review.googlesource.com/54790
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-14 18:45:21 +00:00
Hiroshi Ioka
d02647242d cmd/link: check magic header
Change-Id: I84b0e1d86728a76bc6a87fee4accf6fc43d87006
Reviewed-on: https://go-review.googlesource.com/54814
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-11 01:51:34 +00:00
Ian Lance Taylor
6bb88fc280 cmd/link: use full link, not compile, to test for -no-?pie
This avoids an error from clang when using -nopie during compilation,
and permits us to check that the entire build succeeds.

Updates #21042

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

Fixes #21042

Change-Id: Iadc83ea7a48ea0debc5064c1ee8da4ebff752044
Reviewed-on: https://go-review.googlesource.com/49710
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-07-20 18:52:06 +00:00
Russ Cox
4f2269edbd cmd/link: add -importcfg to specify import resolution
Adds the ability to specify the file location of each imported package,
like in the -importcfg added to cmd/compile in a related CL.
In effect, -importcfg is a generalization of and supersedes -installsuffix
and -L. Of course, those flags will continue to be supported, for
compatibility with other tools.

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

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

For #20579.

Change-Id: Ie4c171bcd3aa2faa446ac340e36516f2f9853882
Reviewed-on: https://go-review.googlesource.com/44851
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-06-06 19:49:58 +00:00
Alex Brainman
1d44c4e378 cmd/link: actually generate .debug_gdb_scripts section on windows
Adjust finddebugruntimepath to look for runtime/debug.go file
instead of runtime/runtime.go. This actually finds runtime.GOMAXPROCS
in every Go executable (including windows).

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

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

Thanks to Egon Elbre and Nick Clifton for investigation.

Fixes #20183
Fixes #20218

Change-Id: I5369a4db3913226aef3d9bd6317446856b0a1c34
Reviewed-on: https://go-review.googlesource.com/43331
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-05-15 06:16:19 +00:00
Elias Naur
45d42fdcea cmd/link/internal/ld: don't link with -no_pie on darwin/arm64
Ever since CL 33301 linking darwin/arm64 excutables has resulted in
warnings like:

ld: warning: -no_pie ignored for arm64

Remove -no_pie on darwin/arm64.

Change-Id: I9f7685351fa8cce29795283e1a24fc7a6753d698
Reviewed-on: https://go-review.googlesource.com/42815
Run-TryBot: Elias Naur <elias.naur@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-07 19:12:26 +00:00
David Crawshaw
27a10f7da7 cmd/link: stop passing unused read_only_relocs
The external darwin linker has been printing:

	ld: warning: -read_only_relocs cannot be used with x86_64

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

Fixes #20246

Change-Id: I1147cf1ff197fdfda228a1349f13627bcf9fc72f
Reviewed-on: https://go-review.googlesource.com/42730
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Todd Neal <todd@tneal.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-05 11:35:58 +00:00
Shenghou Ma
4d7a5edb7e cmd/link/internal/ld: always show output from external linker
Fixes #17935.

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

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

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

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

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

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

No compiler performance changes.

Change-Id: I77b071ab103685ff8e042cee9abb864385488872
Reviewed-on: https://go-review.googlesource.com/40864
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
2017-05-02 00:21:33 +00:00
Michael Hudson-Doyle
3bcb481aa3 cmd/link: rename AttrHidden to AttrNotInSymbolTable
I want to move the SHIDDEN type bit into Attribute, but AttrHidden is already
there and means something completely different, so rename it. (I'll give the
SHIDDEN bit a better name when it moves too).

Change-Id: I075403d9542b7626d4c1f6db9094329c4181aad3
Reviewed-on: https://go-review.googlesource.com/42024
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-04-30 23:28:29 +00:00
Michael Hudson-Doyle
be2ee2a4b4 cmd/internal/objabi, cmd/link: move linker-only symkind values into linker
Many (most!) of the values of objapi.SymKind are used only in the linker, so
this creates a separate cmd/link/internal/ld.SymKind type, removes most values
from SymKind and maps one to the other when reading object files in the linker.

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

Change-Id: I4bbc5aed6713cab3e8de732e6e288eb77be0474c
Reviewed-on: https://go-review.googlesource.com/40985
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-04-27 21:56:12 +00:00
Todd Neal
dc444418d9 cmd/internal: remove duplicate pathToPrefix function
goobj.importPathToPrefix is 3x faster than gc.pathToPrefix so rename and
move it to cmd/internal/objabi which is already imported by both goobj and
gc.

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

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

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

Fixes #15165.
Fixes #20026.

Change-Id: Ic4b92fac7d0d35438e0d20c9579aad4085c5534c
Reviewed-on: https://go-review.googlesource.com/40972
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2017-04-19 00:00:09 +00:00
Michael Hudson-Doyle
743fe0697d cmd/link: replace Segment's linked list of Sections with a slice
Just noticed this in passing.

Change-Id: I58fa828ef58598209ed4cbe4abc6f9f02ffc4844
Reviewed-on: https://go-review.googlesource.com/40896
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-04-18 21:24:32 +00:00
Michael Hudson-Doyle
533ed967c6 cmd/link: only include the version info and export data in ABI hash
Previously the "ABI hash" for a package (used to determine if a loaded shared
library has the ABI expected by its loader) was the hash of the entire
__.PKGDEF file. But that means it depends on the build ID generated by the go
tool for the package, which means that if a file is added (even a .c or .h
file!) to the package, the ABI changes, perhaps uncessarily.

Fixes #19920

Change-Id: If919481e1a03afb350c8a9c7a0666bb90ee90270
Reviewed-on: https://go-review.googlesource.com/40401
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-04-17 22:02:01 +00:00
Joel Sing
9417c022c6 cmd/link,runtime/cgo: enable PT_TLS generation on OpenBSD
OpenBSD 6.0 and later have support for PT_TLS in ld.so(1). Now that OpenBSD
6.1 has been released, OpenBSD 5.9 is no longer officially supported and Go
can start generating PT_TLS for OpenBSD cgo binaries. This also allows us
to remove the workarounds in the OpenBSD cgo runtime.

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

Fixes #19932

Change-Id: I42e75ef9feb5dcd4696add5233497e3cbc48ad52
Reviewed-on: https://go-review.googlesource.com/40331
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-04-11 16:33:16 +00:00
Cherry Zhang
a1cedf0842 cmd/link: canonicalize the "package" of dupok text symbols
Dupok symbols may be defined in multiple packages. Its associated
package is chosen sort of arbitrarily (the first containing package
that the linker loads). Canonicalize its package to the package
with which it will be laid down in text, which is the first package
in dependency order that defines the symbol. So later passes (for
example, trampoline insertion pass) know that the dupok symbol
is laid down along with the package.

Fixes #19764.

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

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

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

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

Change-Id: Ie5ee1f374e50c834652a037f2770118d56c21a2a
Reviewed-on: https://go-review.googlesource.com/38760
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-03-30 22:51:19 +00:00
Russ Cox
18e77673d8 cmd/link: emit a mach-o dwarf segment that dsymutil will accept
Right now, at least with Xcode 8.3, we invoke dsymutil and dutifully
copy what it produces back into the binary, but it has actually dropped
all the DWARF information that we wanted, because it didn't like
the look of go.o.

Make it like the look of go.o.

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

Fixes #19772.

Change-Id: I0082e52c0bc8fc4e289770ec3dc02f39fd61e743
Reviewed-on: https://go-review.googlesource.com/38855
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-03-30 17:31:50 +00:00
Russ Cox
23dc3633ca cmd/link: disable mach-o dwarf munging with -w (in addition to -s)
Might as well provide a way around the mach-o munging
that doesn't require stripping all symbols.
After all, -w does mean no DWARF.

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

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

Fixes #19775.

Change-Id: I18dd4e4b3f59cbf35dad770fd65e6baea5a7347f
Reviewed-on: https://go-review.googlesource.com/38851
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-03-30 02:45:45 +00:00
Alex Brainman
0ad247c6f0 cmd/link: delay calculating pe file parameters after Linkmode is set
For #10776.

Change-Id: Id64a7e35c7cdcd9be16cbe3358402fa379090e36
Reviewed-on: https://go-review.googlesource.com/36975
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-02-16 04:35:36 +00:00
Vladimir Stefanovic
a3b670e333 cmd/link: add external linking support for GOARCH=mips{,le}
Fixes #17792.

Change-Id: If4f24455eec0edb3b221aef6777a681f6c768866
Reviewed-on: https://go-review.googlesource.com/34313
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-12-14 23:51:55 +00:00
David Crawshaw
348a7c5397 cmd/link: hash packages after loading all symbols
Conditioning on the plugin.Open symbol existing before loading all
symbols means sometimes some packages don't have a hash value.

Fixes #17928

Change-Id: I2722449aa58eca08a25117d3ce976f11f805b5ac
Reviewed-on: https://go-review.googlesource.com/33925
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-12-06 14:07:40 +00:00
David Crawshaw
6f31abd23a cmd/compile, cmd/link: weak relocation for ptrTo
Introduce R_WEAKADDROFF, a "weak" variation of the R_ADDROFF relocation
that will only reference the type described if it is in some other way
reachable.

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

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

Fixes #17931

Change-Id: I4d3b53cb9c916c97b3b16e367794eee142247281
Reviewed-on: https://go-review.googlesource.com/33427
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-11-22 03:10:14 +00:00
David Crawshaw
03da2690c9 cmd/link, runtime, plugin: versioning
In plugins and every program that opens a plugin, include a hash of
every imported package.

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

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

Fixes #17832

Change-Id: I4e62c8e1729d322e14b1673bada40fa7a74ea8bc
Reviewed-on: https://go-review.googlesource.com/33161
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-11-15 16:14:27 +00:00
Ian Lance Taylor
53aec79ce0 cmd/link: for -buildmode=exe pass -no-pie to external linker
On some systems the external linker defaults to PIE. On some systems
DT_TEXTREL does not work correctly. When both are true we have a bad
situation: any Go program built with the default buildmode (exe) that
uses external linking will fail to run. Fix this by passing -no-pie to
the external linker, if the option is supported.

Fixes #17847.

Change-Id: I9b5ff97825d8b7f494f96d29c4c04f72b53dbf4e
Reviewed-on: https://go-review.googlesource.com/33106
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-11-11 14:26:15 +00:00
shaharko
80a034642e cmd/compile, cmd/link: stop generating unused go.string.hdr symbols.
name       old s/op    new s/op    delta
LinkCmdGo   0.29 ± 5%   0.29 ± 8%  -2.60%   (p=0.000 n=97+98)

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

Change-Id: I75a1c3b24ea711a15a5d2eae026b70b97ee7bad4
Reviewed-on: https://go-review.googlesource.com/31030
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
2016-10-25 05:17:05 +00:00
Cherry Zhang
7c431cb7f9 cmd/link: insert trampolines for too-far jumps on ARM
ARM direct CALL/JMP instruction has 24 bit offset, which can only
encodes jumps within +/-32M. When the target is too far, the top
bits get truncated and the program jumps wild.

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

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

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

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

TBD: debug info of trampolines?

Fixes #17028.

Change-Id: Idcce347ea7e0af77c4079041a160b2f6e114b474
Reviewed-on: https://go-review.googlesource.com/29397
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-11 13:35:33 +00:00
David Crawshaw
73e7a569b4 cmd/link: plugin support on darwin/amd64
This CL turns some special section marker symbols into real symbols
laid out in the sections they mark. This is to deal with the fact
that dyld on OS X resolves the section marker symbols in any dlopen-ed
Go program to the original section marker symbols in the host program.

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

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

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

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

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

Fixes #15823.

Change-Id: If8117b0e0afb058cbc072258425a35aef2363c92
Reviewed-on: https://go-review.googlesource.com/27790
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-21 20:23:49 +00:00
Michael Hudson-Doyle
324f6ab48c cmd/link: use ctxt.{Lookup,ROLookup} in favour of function versions of same
Done with two eg templates:

package p

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

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

package p

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

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

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

Change-Id: Ic8c534a3fdd332b5420d062ee85bb77a30ad1efb
Reviewed-on: https://go-review.googlesource.com/29346
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-20 04:12:28 +00:00
David Crawshaw
5a597e2d29 cmd/link: replace ld.Link.Diag with ld.Errorf
Instead of using ctxt.Cursym, Errorf takes an explicit *Symbol
parameter. This removes most uses of Cursym and means the *Link
context object is needed in fewer parts of the linker.

All transformations done manually, as wiring Cursym is tricky.

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

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

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

Change-Id: I5202fcc3f73e3dfddfea3ec7b772e16da51195da
Reviewed-on: https://go-review.googlesource.com/29331
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-18 21:59:09 +00:00
David Crawshaw
6007c8c76b cmd/link: attempt to rationalize linkmode init
This CL gives Linkmode a type, switches it to the standard flag
handling mechanism, and deduplicates some logic.

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

Fixes #12848

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

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

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

Change-Id: I099b6f38dda26306eba5c41dbe7862f5a5918d95
Reviewed-on: https://go-review.googlesource.com/27820
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-16 14:49:13 +00:00
David Crawshaw
d185cc3b64 cmd/link: disable internal PIE for now
There's more work to do.

Updates #17068

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

Change-Id: I5ce01d1974e5d4b1a8cbcc8b08157477631d8d24
Reviewed-on: https://go-review.googlesource.com/28543
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-11 21:53:21 +00:00
David Crawshaw
44ee2b00db cmd/link: optimize TLS IE to LE in build mode PIE
When cmd/compile generates position-independent code on linux
(the -shared flag), it refers to runtime.tlsg as a TLS IE variable.

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

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

Part of adding PIE internal linking on linux/amd64.

Change-Id: I1eb068d0ec774724944c6b308aa5084582ecde0b
Reviewed-on: https://go-review.googlesource.com/28540
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-11 21:13:42 +00:00