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Commit Graph

333 Commits

Author SHA1 Message Date
David Crawshaw
d9d1399eea cmd/link: mark rel.ro segment as PT_GNU_RELRO
Details: http://www.airs.com/blog/archives/189

Part of adding PIE internal linking on linux/amd64.

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

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

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

Part of adding PIE internal linking on linux/amd64.

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

Part of adding PIE internal linking on linux/amd64.

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

Part of adding PIE internal linking on linux/amd64.

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

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

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

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

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

Remove duplicate string to headtype list.

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

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

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

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

Fixes #8756

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

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

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

I excluded any cmd/vendor changes from the commit.

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

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

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

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

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

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

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

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

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

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

Grab architecture of .o files from header.

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

Fixes #13862

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

Updates #16818

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

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

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

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

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

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

Updates #16818

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

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

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

Updates #16818

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

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

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

Updates #16818

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

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

Change-Id: I2412b224c847dd640f9253125d30cd5f911ce00c
Reviewed-on: https://go-review.googlesource.com/27414
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>
2016-08-21 22:17:24 +00:00
Michael Matloob
64f5023e6f cmd/link: remove global Bso variable
Bso is already a member on ld.Link. Use that instead of
the global.

Updates #16818

Change-Id: Icfc0f6cb1ff551e8129253fb6b5e0d6a94479f51
Reviewed-on: https://go-review.googlesource.com/27470
Run-TryBot: Michael Matloob <matloob@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-08-21 18:51:21 +00:00
Michael Matloob
4338e5a891 cmd/link/internal: remove global Ctxt variable
This change threads the *ld.Link Ctxt variable through
code in arch-specific packages. This removes all remaining
uses of Ctxt, so remove the global variable too.

This CL continues the work in golang.org/cl/27408

Updates #16818

Change-Id: I5f4536847a1825fd0b944824e8ae4e122ec0fb78
Reviewed-on: https://go-review.googlesource.com/27459
Run-TryBot: Michael Matloob <matloob@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-08-21 18:18:39 +00:00
Michael Matloob
2f783c3458 cmd/link/internal: thread *ld.Link through calls
Ctxt is a global defined in cmd/link/internal/ld of type *ld.Link.
Start threading a *ld.Link through function calls instead of
relying on the global variable.

Ctxt is still used as a global by the architecture-specific packages,
but I plan to fix that in a subsequent CL.

Change-Id: I77a3a58bd396fafd959fa1d8b1c83008a9f5a7fb
Reviewed-on: https://go-review.googlesource.com/27408
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
2016-08-21 15:56:43 +00:00
Michael Matloob
a072fc2e67 cmd/link/internal: rename LSym to Symbol, and add a doc comment.
I'd also like to document some of its fields, but I don't know
what they are.

Change-Id: I87d341e255f785d351a8a73e645be668e02b2689
Reviewed-on: https://go-review.googlesource.com/27399
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-08-19 22:10:04 +00:00
Michael Matloob
795ad07b3b cmd: generate DWARF for functions in compile instead of link.
This is a copy of golang.org/cl/22092 by Ryan Brown.

Here's his original comment:
On my machine this increases the average time for 'go build cmd/go' from
2.25s to 2.36s. I tried to measure compile and link separately but saw
no significant change.

Change-Id: If0d2b756d52a0d30d4eda526929c82794d89dd7b
Reviewed-on: https://go-review.googlesource.com/25311
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-08-18 15:06:27 +00:00
Michael Hudson-Doyle
b5e43e669a cmd/link: when dynlinking, do not mangle short symbol names
When dynamically linking, a type symbol's name is replaced with a name based on
the SHA1 of the name as type symbol's names can be very long.  However, this
can make a type's symbol name longer in some cases. So skip it in that case.
One of the symbols this changes the treatment of is 'type.string' and that fixes a
bug where -X doesn't work when dynamically linking.

Fixes #16671

Change-Id: If5269038261b76fb0ec52e25a9c1d64129631e3c
Reviewed-on: https://go-review.googlesource.com/26890
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-08-16 00:37:09 +00:00
Keith Randall
2cbdd55d64 [dev.ssa] cmd/compile: fix PIC for SSA-generated code
Access to globals requires a 2-instruction sequence on PIC 386.

    MOVL foo(SB), AX

is translated by the obj package into:

    CALL getPCofNextInstructionInTempRegister(SB)
    MOVL (&foo-&thisInstruction)(tmpReg), AX

The call returns the PC of the next instruction in a register.
The next instruction then offsets from that register to get the
address required.  The tricky part is the allocation of the
temp register.  The legacy compiler always used CX, and forbid
the register allocator from allocating CX when in PIC mode.
We can't easily do that in SSA because CX is actually a required
register for shift instructions. (I think the old backend got away
with this because the register allocator never uses CX, only
codegen knows that shifts must use CX.)

Instead, we allow the temp register to be anything.  When the
destination of the MOV (or LEA) is an integer register, we can
use that register.  Otherwise, we make sure to compile the
operation using an LEA to reference the global.  So

    MOVL AX, foo(SB)

is never generated directly.  Instead, SSA generates:

    LEAL foo(SB), DX
    MOVL AX, (DX)

which is then rewritten by the obj package to:

    CALL getPcInDX(SB)
    LEAL (&foo-&thisInstruction)(DX), AX
    MOVL AX, (DX)

So this CL modifies the obj package to use different thunks
to materialize the pc into different registers.  We use the
registers that regalloc chose so that SSA can still allocate
the full set of registers.

Change-Id: Ie095644f7164a026c62e95baf9d18a8bcaed0bba
Reviewed-on: https://go-review.googlesource.com/25442
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-08-09 15:50:07 +00:00
David Crawshaw
af0fc83985 cmd/compile, etc: handle many struct fields
This adds 8 bytes of binary size to every type that has methods. It is
the smallest change I could come up with for 1.7.

Fixes #16037

Change-Id: Ibe15c3165854a21768596967757864b880dbfeed
Reviewed-on: https://go-review.googlesource.com/24070
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-06-14 15:32:34 +00:00
Keith Randall
5701174c52 cmd/link: put padding between functions, not at the end of a function
Functions should be declared to end after the last real instruction, not
after the last padding byte. We achieve this by adding the padding while
assembling the text section in the linker instead of adding the padding
to the function symbol in the compiler. This change makes dtrace happy.

TODO: check that this works with external linking

Fixes #15969

Change-Id: I973e478d0cd34b61be1ddc55410552cbd645ad62
Reviewed-on: https://go-review.googlesource.com/24040
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-06-13 14:05:52 +00:00
Ian Lance Taylor
6901b08482 cmd/link: avoid name collision with DWARF .def suffix
Adding a .def suffix for DWARF info collided with the DWARF info,
without the suffix, for a method named def. Change the suffix to ..def
instead.

Fixes #15926.

Change-Id: If1bf1bcb5dff1d7f7b79f78e3f7a3bbfcd2201bb
Reviewed-on: https://go-review.googlesource.com/23733
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-06-03 16:56:29 +00:00
Michael Hudson-Doyle
2c1791b13b cmd/link: suppress PIE whenever externally linking with a sanitizer
golang.org/issue/15443 complained that a race-enabled PIE binary crashed at
startup, but other ways of linking in tsan (or other sanitizers) such as

 #cgo CFLAGS: -fsanitize=thread
 #cgo LDFLAGS: -fsanitize=thread

have the same problem. Pass -no-pie to the host linker (if supported) if any
-fsanitizer=foo cgo LDFLAG is seen when linking.

Fixes #15887

Change-Id: Id799770f8d045f6f40fa8c463563937a5748d1a8
Reviewed-on: https://go-review.googlesource.com/23535
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-05-31 20:57:57 +00:00
Michael Hudson-Doyle
2a6544b604 cmd/go, cmd/link: set LC_ALL=C when checking if host compiler supports -no-pie
Fixes #15900

Change-Id: Ieada5f4e3b3b2ae358414e013f3090b4b820569b
Reviewed-on: https://go-review.googlesource.com/23536
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-05-31 20:57:21 +00:00
Russ Cox
7fdec6216c build: enable framepointer mode by default
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>
2016-05-26 19:02:00 +00:00
Austin Clements
adff422779 cmd/link/internal/ld: fix DWARF offsets with GOEXPERIMENT=framepointer
The offsets computed by the DWARF expressions for local variables
currently don't account for the extra stack slot used by the frame
pointer when GOEXPERIMENT=framepointer is enabled.

Fix this by adding the extra stack slot to the offset.

This fixes TestGdbPython with GOEXPERIMENT=framepointer.

Updates #15840.

Change-Id: I1b2ebb2750cd22266f4a89ec8d9e8bfa05fabd19
Reviewed-on: https://go-review.googlesource.com/23458
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-05-26 13:54:02 +00:00
Elias Naur
f2f3b6cd8f cmd/link: fix ARM gold linker check
CL 23400 introduced a check to make sure the gold linker is used
on ARM host links. The check itself works, but the error checking
logic was reversed; fix it.

I manually verified that the check now correctly rejects host links
on my RPi2 running an ancient rasbian without the gold linker
installed.

Updates #15696

Change-Id: I927832620f0a60e91a71fdedf8cbd2550247b666
Reviewed-on: https://go-review.googlesource.com/23421
Run-TryBot: Elias Naur <elias.naur@gmail.com>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-25 11:50:49 +00:00
David Crawshaw
a0abecf102 cmd/link: ensure -fuse-ld=gold uses gold
Fixes #15696

Change-Id: I134e918dc56f79a72a04aa54f415371884113d2a
Reviewed-on: https://go-review.googlesource.com/23400
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-05-24 18:56:11 +00:00
Aliaksandr Valialkin
376e641540 cmd: fixed certain vet warnings
Updates #11041

Change-Id: I7f2583d08f344d6622027c5e8a5de1f5d2f2881c
Reviewed-on: https://go-review.googlesource.com/23082
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-12 15:58:30 +00:00
Russ Cox
feb6131b1a cmd/compile: add -linkobj flag to allow writing object file in two parts
This flag is experimental and the semantics may change
even after Go 1.7 is released. There are no changes to code
not using the flag.

The first part is for reading by future compiles.
The second part is for reading by the final link step.
Splitting the file this way allows distributed build systems
to ship the compile-input part only to compile steps and
the linker-input part only to linker steps.

The first part is basically just the export data,
and the second part is basically everything else.
The overall files still have the same broad structure,
so that existing tools will work with both halves.
It's just that various pieces are empty in the two halves.

This also copies the two bits of data the linker needed from
export data into the object header proper, so that the linker
doesn't need any export data at all. That eliminates a TODO
that was left for switching to the binary export data.
(Now the linker doesn't need to know about the switch.)

The default is still to write out a combined output file.
Nothing changes unless you pass -linkobj to the compiler.
There is no support in the go command for -linkobj,
since the go command doesn't copy objects around.
The expectation is that other build systems (like bazel, say)
might take advantage of this.

The header adjustment and the option for the split output
was intended as part of the zip archives, but the zip archives
have been cut from Go 1.7. Doing this to the current archives
both unblocks one step in the switch to binary export data
and enables alternate build systems to experiment with the
new flag using the Go 1.7 release.

Change-Id: I8b6eab25b8a22b0a266ba0ac6d31e594f3d117f3
Reviewed-on: https://go-review.googlesource.com/22500
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-05-09 17:31:45 +00:00
Joel Sing
0b6e5e3d73 cmd/link: specify correct size for dynamic symbols in 386 elf output
Currently 386 ELF binaries are generated with dynamic symbols that have
a size of zero bytes, even though the symbol in the symbol table has
the correct size. Fix this by specifying the correct size when creating
dynamic symbols.

Issue found on OpenBSD -current, where ld.so is now producing link
warnings due to mismatched symbol sizes.

Fixes #15593.

Change-Id: Ib1a12b23ff9159c61ac980bf48a983b86f3df256
Reviewed-on: https://go-review.googlesource.com/22912
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-08 05:34:56 +00:00
Cherry Zhang
3c4ebd2023 cmd/link: fix external linker argument for mips64
I overlooked it when rebasing CL 19803.

Change-Id: Ife9d6bcc6a772715d137af903c64bafac0cdb216
Reviewed-on: https://go-review.googlesource.com/22797
Reviewed-by: Minux Ma <minux@golang.org>
2016-05-05 14:57:45 +00:00
Cherry Zhang
dcd613862b cmd/link/internal/ld: force external linking for mips64x with cgo
cgo internal linking is not supported yet (issue #14449).

Change-Id: Ic968916383d77b7f449db8f230c928a1e81939e0
Reviewed-on: https://go-review.googlesource.com/19807
Reviewed-by: Minux Ma <minux@golang.org>
2016-05-04 16:41:24 +00:00