Only internal linking without cgo is supported for now.
Change-Id: Ie6074a8ff3ec13605b72028f2d60758034f87185
Reviewed-on: https://go-review.googlesource.com/14444
Reviewed-by: Minux Ma <minux@golang.org>
They reportedly occur with LLVM 3.7 on FreeBSD ARM.
Fixes#13139.
Change-Id: Ia7d053a8662696b1984e81fbd1d908c951c35a98
Reviewed-on: https://go-review.googlesource.com/16667
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
When dynamically linking, we want references to functions defined
in this module to always be to the function object, not to the
PLT. We force this by writing an additional local symbol for
every global function symbol and making all relocations against
the global symbol refer to this local symbol instead. This is
approximately equivalent to the ELF linker -Bsymbolic-functions
option, but that is buggy on several platforms.
Change-Id: Ie6983eb4d1947f8543736fd349f9a90df3cce91a
Reviewed-on: https://go-review.googlesource.com/16436
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Depends on external linking right now. I have no immediate use for
this, but wanted to check how hard it is to support as android/amd64
is coming and it will require PIE.
Change-Id: I65c6b19159f40db4c79cf312cd0368c2b2527bfd
Reviewed-on: https://go-review.googlesource.com/16072
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The -msan option causes the linker to link against the runtime/msan
package in order to use the C/C++ memory sanitizer.
This CL passes tests but is not usable by itself. The actual
runtime/msan package, and support for -msan in the go tool and the
compiler, and tests, are in separate CLs.
Change-Id: I02c097393b98c5b80e40ee3dbc167a8b4d23efe0
Reviewed-on: https://go-review.googlesource.com/16161
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Shared libraries on ppc64le will require a larger minimum stack frame (because
the ABI mandates that the TOC pointer is available at 24(R1)). Part 2b of
preparing for that is to have all the code in the linker that needs to know
this size of this call a function to find out.
Change-Id: I246363840096db22e44beabbe38b61d60c1f31ad
Reviewed-on: https://go-review.googlesource.com/15675
Reviewed-by: Ian Lance Taylor <iant@golang.org>
For #10807
Change-Id: Ied826d06cb622edf6413b6f2cdcc46987ab0b05a
Reviewed-on: https://go-review.googlesource.com/16054
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Go cannot allow lazy PLT resolution when calling between Go functions because
the lazy resolution can use more stack than is available. Lazy resolution is
disabled by passing -z now to the system linker, but unfortunately was only
passed when linking to a Go shared library. That sounds fine, but the shared
library containing the runtime is not linked to any other Go shared library but
calls main.init and main.main via a PLT, and before this fix this did use lazy
resolution. (For some reason this never caused a problem on intel, but it
breaks on ppc64le). Fortunately the fix is very simple: always pass -z now to
the system linker when dynamically linking Go.
Change-Id: I7806d40aac80dcd1e56b95864d1cfeb1c42614e2
Reviewed-on: https://go-review.googlesource.com/15870
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Go shared libraries do not support dlclose, and there is no likelihood
that they will suppose dlclose in the future. Set the DF_1_NODELETE
flag to tell the dynamic linker to not attempt to remove them from
memory. This makes the shared library act as though every call to
dlopen passed the RTLD_NODELETE flag.
Fixes#12582.
Update #11100.
Update #12873.
Change-Id: Id4b6e90a1b54e2e6fc8355b5fb22c5978fc762b4
Reviewed-on: https://go-review.googlesource.com/15605
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
It's particularly nice to get rid of the android special cases in the linker.
Change-Id: I516363af7ce8a6b2f196fe49cb8887ac787a6dad
Reviewed-on: https://go-review.googlesource.com/14197
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Not sure how I managed to do this, or get it past review.
Change-Id: I141b97ef8e09dcc9c910c45493a584a3dced2b28
Reviewed-on: https://go-review.googlesource.com/14634
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently Go produces shared libraries that cannot be shared between processes
because they have relocations against the text segment (not text section). This
fixes this by moving some data to sections with magic names recognized by the
static linker.
The change in genasmsym to add STYPELINK to the switch should fix things on
darwin/arm64.
Fixes#10914
Updates #9210
Change-Id: Iab4a6678dd04cec6114e683caac5cf31b1063309
Reviewed-on: https://go-review.googlesource.com/14306
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This reverts commit 2c2cbb69c8dad1325f0a4b289417da73fd90f4b0.
Broke darwin/arm64
Change-Id: Ibd2dea475d6ce6a8b4b40e2da19a83fc0514025d
Reviewed-on: https://go-review.googlesource.com/14301
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently Go produces shared libraries that cannot be shared between processes
because they have relocations against the text segment (not text section). This
fixes this by moving some data to sections with magic names recognized by the
static linker.
Fixes#10914
Updates #9210
Change-Id: I7178daadc0ae87953d5a084aa3d580f4e3b46d47
Reviewed-on: https://go-review.googlesource.com/10300
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
And do it properly so freebsd and nacl still work.
Change-Id: I6f9f30e93ceae6dee59215ed608c6a158bdbdbb0
Reviewed-on: https://go-review.googlesource.com/14280
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This was always a bit confusing, but it also fixes a problem: runtime.firstmoduledata
was always overridden in the linker to be a local symbol but cmd/internal/obj had
already rewritten code accessing it to access it via the GOT. This works on amd64, but
causes link failures on other platforms (e.g. arm64).
Change-Id: I9b8153af74b4d0f092211d63a000d15818f39773
Reviewed-on: https://go-review.googlesource.com/13786
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The nosplit stack overflow checks were confused about morestack.
The comment about not having correct SP information at the call
to morestack was true, but that was a real bug, not something to
work around. I fixed that problem in CL 12144. With that fixed,
no need to special-case morestack in the way done here.
This cleanup and simplification of the code was the first step
to fixing a bug that happened when I started working on the
arm64 frame size adjustments, but the cleanup was sufficient
to make the bug go away.
For #9880.
Change-Id: I16b69a5c16b6b8cb4090295d3029c42d606e3b9b
Reviewed-on: https://go-review.googlesource.com/12846
Reviewed-by: Austin Clements <austin@google.com>
On Windows, gcc -o foo will generate foo.exe. Prevent that from
happening by adding a final '.' if necessary so that GCC thinks that
the file already has an extension.
Also remove the initial output file when doing an external link, and
use mayberemoveoutfile, not os.Remove, when building an archive
(otherwise we will do the wrong thing for -buildmode=c-archive -o
/dev/null).
I didn't add a test, as it requires using cgo and -o on Windows.
Fixes#11725.
Change-Id: I6ea12437bb6b4b9b8ee5c3b52d83509fa2437b2d
Reviewed-on: https://go-review.googlesource.com/12243
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Russ Cox <rsc@golang.org>
Same as we do for string symbols.
Fixes#11583.
Change-Id: Ia9264f6faf486697d987051b7f9851d37d8ad381
Reviewed-on: https://go-review.googlesource.com/12531
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This code used to only be run for ELF, with the predictable
result that using -s with external linking broke on Windows and OS X.
Moving it here should fix Windows and does fix OS X.
CL 10835 also claims to fix the crash on Windows.
I don't know whether it does so correctly, but regardless,
this CL should make that one a no-op.
Fixes#10254.
Change-Id: I2e7b45ab0c28568ddbb1b50581dcc157ae0e7ffe
Reviewed-on: https://go-review.googlesource.com/11695
Reviewed-by: David Crawshaw <crawshaw@golang.org>
All of the heavy-lifting was done by minux@, with his external-linking support
for darwin/arm64: golang.org/cl/8781
Change-Id: I7c9fbc19246f418c065c92fb2c13c00026ff0f82
Reviewed-on: https://go-review.googlesource.com/11127
Run-TryBot: Srdjan Petrovic <spetrovic@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This makes the behaviour match what happens when duplicate symbols are read
from regular object files and fixes errors about cgoAlwaysFalse when linking
an executable that uses cgo against a shared library.
Change-Id: Ibb8cd8fe3f7813cde504b7483f1e857868d7e063
Reviewed-on: https://go-review.googlesource.com/11117
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Change-Id: If11621985c0a5a1f2133cdc974f37fd944b93e5e
Reviewed-on: https://go-review.googlesource.com/10808
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Also fix the interaction between -buildmode and -shared.
It's okay for -shared to change the default build mode,
but it's not okay for it to silently override an explicit -buildmode=exe.
Change-Id: Id40f93d140cddf75b19e262b3ba4856ee09a07ba
Reviewed-on: https://go-review.googlesource.com/10315
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
stkcheck is flow-insensitive: It processes calls in PC order.
Since morestack was always the first call in a function,
it was a safe, conservative approximation to simply adjust stack
space as we went, recognizing morestack when it showed up.
Subsequent CLS will rearrange the function prologue;
morestack may no longer be the first call in a function.
Introducing flow-sensitivity to stkcheck would allow this,
and possibly allow a smaller stackguard.
It is also a high risk change and possibly expensive.
Instead, assume that all calls to morestack occur as
part of the function prologue, no matter where they
are located in the program text.
Updates #10587.
Change-Id: I4dcdd4256a980fc4bc433a68a10989ff57f7034f
Reviewed-on: https://go-review.googlesource.com/10496
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
We already read the address of a gcmask/gcprog out of the type data, but I
didn't know how many bytes to read. But it turns out that it's easy to
calculate, so change to do that. This means that we no longer depend on the
local symbols being present, allowing me to strip the shared libraries for
distribution and make them a lot smaller.
As a bonus, this makes LSym another 24 bytes smaller, down to 296 bytes now.
Change-Id: I379d359e28d63afae6753efd23efdf1fbb716992
Reviewed-on: https://go-review.googlesource.com/10377
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The motivation for this is the innocuous looking test case that is added. This
creates a stack exe -> libdep2.so -> libdep.so -> libruntime.so. The problem
comes from the fact that a function from libdep.so gets inlined all the way
into exe. This (unsurprisingly) means that the object file for exe references
symbols from libdep.so, which means that -ldep needs to be passed when linking
exe and it isn't. The fix is simply to pass it -- there is no harm in passing
it when it's not needed.
The thing is, it's not clear at all in the current code to see how the linker
can know that libdep2 is linked against libdep. It could look through the
DT_NEEDED entries in libdep2 and try to guess which are Go libraries, but it
feels better to be explicit. So this adds another SHT_NOTE section that lists
the shared libraries a shared library was linked against, and makes sure the
complete set of depended upon shared libraries is passed to the external
linker.
Change-Id: I79aa6f98b4db4721d657a7eb7b7f062269bf49e2
Reviewed-on: https://go-review.googlesource.com/10376
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This makes for a more stable API for tools (including cmd/link itself) to
extract the abi hash from a shared library and makes it possible at all for a
library that has had the local symbol table removed.
The existing note-writing code only supports writing notes into the very start
of the object file so they are easy to find in core dumps. This doesn't apply
to the "go" notes and means that all notes have to fit into a fixed size
budget. That's annoying now we have more notes (and the next CL will add
another one) so this does a little bit of work to make adding notes that do not
have to go at the start of the file easier and moves the writing of the package
list note over to that mechanism, which lets me revert a hack that increased
the size budget mentioned above for -buildmode=shared builds.
Change-Id: I6077a68d395c8a2bc43dec8506e73c71ef77d9b9
Reviewed-on: https://go-review.googlesource.com/10375
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The LSym.Section and Section.Elfsect fields were defined as interface{} but
always had the same concrete type (*Section and *ElfShdr respectively) so just
define them with that type. Reduces size of LSym from 328 to 320 bytes and
reduces best-of-10 maxresident size from 246028k to 238036k when linking
libstd.so.
Change-Id: Ie7112c53e4c2c7ce5fe233b81372aa5633f572e8
Reviewed-on: https://go-review.googlesource.com/10410
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
It can be useful when debugging to be able to see what the external
linker is doing even when it succeeds. In particular this permits
passing -v to the external linker to see precisely what it is doing.
Change-Id: Ifed441912d97bbebea20303fdb899e140b380215
Reviewed-on: https://go-review.googlesource.com/10363
Reviewed-by: Minux Ma <minux@golang.org>
This CL removes the remaining visible uses of the "architecture letter" concept.
(They are no longer in tool names nor in source directory names.)
Because the architecture letter concept is now gone, delete GOCHAR
from "go env" output, and change go/build.ArchChar to return an
error always.
The architecture letter is still used in the compiler and linker sources
as a clumsy architecture enumeration, but that use is not visible to
Go users and can be cleaned up separately.
Change-Id: I4d97a38f372003fb610c9c5241bea440d9dbeb8d
Reviewed-on: https://go-review.googlesource.com/10289
Reviewed-by: Rob Pike <r@golang.org>
Trivial merging of 5g, 6g, ... into go tool compile,
and similarlly 5l, 6l, ... into go tool link.
The files compile/main.go and link/main.go are new.
Everything else in those directories is a move followed by
change of imports and package name.
This CL breaks the build. Manual fixups are in the next CL.
See golang-dev thread titled "go tool compile, etc" for background.
Change-Id: Id35ff5a5859ad9037c61275d637b1bd51df6828b
Reviewed-on: https://go-review.googlesource.com/10287
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Rob Pike <r@golang.org>
