Otherwise the default computation in symalign kicked in, setting the
alignment to be too high. This didn't matter with GNU ld, which put
each loadable note into a separate PT_NOTE segment, but it did matter
with gold which accumulated them all into a single PT_NOTE segment,
respecting the requested alignment. In the single PT_NOTE segment
generated by gold, the incorrect section alignment made the notes
unreadable.
Fixes#21564
Change-Id: I15eb408bb04a2566c9fdfb6828e14188d9ef2280
Reviewed-on: https://go-review.googlesource.com/58290
Reviewed-by: Russ Cox <rsc@golang.org>
Some debuggers use the declaration line to avoid showing variables
before they're declared. Emit them for local variables and function
parameters.
DW_AT_decl_file would be nice too, but since its value is an index
into a table built by the linker, that's dramatically harder. In
practice, with inlining disabled it's safe to assume that all a
function's variables are declared in the same file, so this should still
be pretty useful.
Change-Id: I8105818c8940cd71bc5473ec98797cce2f3f9872
Reviewed-on: https://go-review.googlesource.com/44350
Reviewed-by: David Chase <drchase@google.com>
Change-Id: I7f7b1e7ef832d53a93562b08ae914d023247c2c0
Reviewed-on: https://go-review.googlesource.com/56312
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
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>
TestSizes has been added in CL 50170. This test is
failing on Plan 9 because executables don't have
a DWARF symbol table.
Fixes#21480.
Change-Id: I51079abdc18ad944617bdbcfe2dad970a0cea0f2
Reviewed-on: https://go-review.googlesource.com/56210
Run-TryBot: David du Colombier <0intro@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The DWARF entries for type-specific sudog entries used the
channel value type instead of a pointer-to-value type for the elem field.
Fixes#21094
R=go1.10
Change-Id: I3f63a5664f42b571f729931309f2c9f6f38ab031
Reviewed-on: https://go-review.googlesource.com/50170
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TestSizes has been added in CL 55551. This test is
failing on Plan 9 because executables don't have
a DWARF symbol table.
Fixes#21453.
Change-Id: I560611b49aea5417e8c5ac0cec6c7882bd9f8335
Reviewed-on: https://go-review.googlesource.com/55692
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
ld.SymKind and objabi.RelocType have string representations,
which is human friendly. Prefer to use it.
Change-Id: I458ee0ca5866be0db8462c36cd053561a8206c95
Reviewed-on: https://go-review.googlesource.com/55253
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Only set MH_NOUNDEFS if there are no undefined symbols.
Doesn't seem to matter, but may as well do it right.
Change-Id: I6c472e000578346c28cf0e10f24f870e3a0de628
Reviewed-on: https://go-review.googlesource.com/55310
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
They are currently not given a size, which makes the DWARF reader
very confused. Particularly things like [4]func() get a size of -4, not 32.
Fixes#21097
Change-Id: I01e754134d82fbbe6567e3c7847a4843792a3776
Reviewed-on: https://go-review.googlesource.com/55551
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Also, unexport Machoadddynlib
n=`go test -c crypto/x509 && otool -l x509.test | grep libSystem | wc -l`
Before this CL, n = 3.
After this CL, n = 1.
on my environment.
Change-Id: Ic7b8157435cc85086404860dc6c84eb0aecc5d19
Reviewed-on: https://go-review.googlesource.com/44771
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Avelino <t@avelino.xxx>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
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>
We might want to replace some linker's feature by debug/macho in future.
This CL gathers information of required constants.
Change-Id: Iea14abdb32709a4f5404a17874f9c925d29ba999
Reviewed-on: https://go-review.googlesource.com/55252
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
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>
This change enables buildmode c-shared on ppc64le.
A bug was fixed in runtime/rt0_linux_ppc64le.s that was necessary to
make this work. In _rt0_ppc64le_linux_lib, there is code to store
the value of r2 onto the caller's stack. However, if this file
is compiled using a build mode that maintains the TOC address in
r2, then instructions will be inserted at the beginning of this
function to generate the r2 value for the callee, not the caller.
That means the r2 value for the callee is stored onto the caller's
stack. If caller and callee don't have the same r2 values, then
the caller will restore the wrong r2 value after it returns. This
situation can happen when using dlopen since the caller of this
function will be in ld64.so and will definitely have a different
TOC.
Updates #20756
Change-Id: I6e165e0d0716e73721bbbcc520e8302e4856e3ba
Reviewed-on: https://go-review.googlesource.com/53890
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Debuggers use DWARF information to find local variables on the
stack and in registers. Prior to this CL, the DWARF information for
functions claimed that all variables were on the stack at all times.
That's incorrect when optimizations are enabled, and results in
debuggers showing data that is out of date or complete gibberish.
After this CL, the compiler is capable of representing variable
locations more accurately, and attempts to do so. Due to limitations of
the SSA backend, it's not possible to be completely correct.
There are a number of problems in the current design. One of the easier
to understand is that variable names currently must be attached to an
SSA value, but not all assignments in the source code actually result
in machine code. For example:
type myint int
var a int
b := myint(int)
and
b := (*uint64)(unsafe.Pointer(a))
don't generate machine code because the underlying representation is the
same, so the correct value of b will not be set when the user would
expect.
Generating the more precise debug information is behind a flag,
dwarflocationlists. Because of the issues described above, setting the
flag may not make the debugging experience much better, and may actually
make it worse in cases where the variable actually is on the stack and
the more complicated analysis doesn't realize it.
A number of changes are included:
- Add a new pseudo-instruction, RegKill, which indicates that the value
in the register has been clobbered.
- Adjust regalloc to emit RegKills in the right places. Significantly,
this means that phis are mixed with StoreReg and RegKills after
regalloc.
- Track variable decomposition in ssa.LocalSlots.
- After the SSA backend is done, analyze the result and build location
lists for each LocalSlot.
- After assembly is done, update the location lists with the assembled
PC offsets, recompose variables, and build DWARF location lists. Emit the
list as a new linker symbol, one per function.
- In the linker, aggregate the location lists into a .debug_loc section.
TODO:
- currently disabled for non-X86/AMD64 because there are no data tables.
go build -toolexec 'toolstash -cmp' -a std succeeds.
With -dwarflocationlists false:
before: f02812195637909ff675782c0b46836a8ff01976
after: 06f61e8112a42ac34fb80e0c818b3cdb84a5e7ec
benchstat -geomean /tmp/220352263 /tmp/621364410
completed 15 of 15, estimated time remaining 0s (eta 3:52PM)
name old time/op new time/op delta
Template 199ms ± 3% 198ms ± 2% ~ (p=0.400 n=15+14)
Unicode 96.6ms ± 5% 96.4ms ± 5% ~ (p=0.838 n=15+15)
GoTypes 653ms ± 2% 647ms ± 2% ~ (p=0.102 n=15+14)
Flate 133ms ± 6% 129ms ± 3% -2.62% (p=0.041 n=15+15)
GoParser 164ms ± 5% 159ms ± 3% -3.05% (p=0.000 n=15+15)
Reflect 428ms ± 4% 422ms ± 3% ~ (p=0.156 n=15+13)
Tar 123ms ±10% 124ms ± 8% ~ (p=0.461 n=15+15)
XML 228ms ± 3% 224ms ± 3% -1.57% (p=0.045 n=15+15)
[Geo mean] 206ms 377ms +82.86%
name old user-time/op new user-time/op delta
Template 292ms ±10% 301ms ±12% ~ (p=0.189 n=15+15)
Unicode 166ms ±37% 158ms ±14% ~ (p=0.418 n=15+14)
GoTypes 962ms ± 6% 963ms ± 7% ~ (p=0.976 n=15+15)
Flate 207ms ±19% 200ms ±14% ~ (p=0.345 n=14+15)
GoParser 246ms ±22% 240ms ±15% ~ (p=0.587 n=15+15)
Reflect 611ms ±13% 587ms ±14% ~ (p=0.085 n=15+13)
Tar 211ms ±12% 217ms ±14% ~ (p=0.355 n=14+15)
XML 335ms ±15% 320ms ±18% ~ (p=0.169 n=15+15)
[Geo mean] 317ms 583ms +83.72%
name old alloc/op new alloc/op delta
Template 40.2MB ± 0% 40.2MB ± 0% -0.15% (p=0.000 n=14+15)
Unicode 29.2MB ± 0% 29.3MB ± 0% ~ (p=0.624 n=15+15)
GoTypes 114MB ± 0% 114MB ± 0% -0.15% (p=0.000 n=15+14)
Flate 25.7MB ± 0% 25.6MB ± 0% -0.18% (p=0.000 n=13+15)
GoParser 32.2MB ± 0% 32.2MB ± 0% -0.14% (p=0.003 n=15+15)
Reflect 77.8MB ± 0% 77.9MB ± 0% ~ (p=0.061 n=15+15)
Tar 27.1MB ± 0% 27.0MB ± 0% -0.11% (p=0.029 n=15+15)
XML 42.7MB ± 0% 42.5MB ± 0% -0.29% (p=0.000 n=15+15)
[Geo mean] 42.1MB 75.0MB +78.05%
name old allocs/op new allocs/op delta
Template 402k ± 1% 398k ± 0% -0.91% (p=0.000 n=15+15)
Unicode 344k ± 1% 344k ± 0% ~ (p=0.715 n=15+14)
GoTypes 1.18M ± 0% 1.17M ± 0% -0.91% (p=0.000 n=15+14)
Flate 243k ± 0% 240k ± 1% -1.05% (p=0.000 n=13+15)
GoParser 327k ± 1% 324k ± 1% -0.96% (p=0.000 n=15+15)
Reflect 984k ± 1% 982k ± 0% ~ (p=0.050 n=15+15)
Tar 261k ± 1% 259k ± 1% -0.77% (p=0.000 n=15+15)
XML 411k ± 0% 404k ± 1% -1.55% (p=0.000 n=15+15)
[Geo mean] 439k 755k +72.01%
name old text-bytes new text-bytes delta
HelloSize 694kB ± 0% 694kB ± 0% -0.00% (p=0.000 n=15+15)
name old data-bytes new data-bytes delta
HelloSize 5.55kB ± 0% 5.55kB ± 0% ~ (all equal)
name old bss-bytes new bss-bytes delta
HelloSize 133kB ± 0% 133kB ± 0% ~ (all equal)
name old exe-bytes new exe-bytes delta
HelloSize 1.04MB ± 0% 1.04MB ± 0% ~ (all equal)
Change-Id: I991fc553ef175db46bb23b2128317bbd48de70d8
Reviewed-on: https://go-review.googlesource.com/41770
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
The linker is pretty good at combining a bunch of symbols into a
section, so let it do .debug_ranges the normal way. Along the way,
remove a bunch of globals that were only used by one function that would
only be called once per invocation.
Change-Id: I1a528a438b193c41e7c444e8830516b07f11affc
Reviewed-on: https://go-review.googlesource.com/43890
Reviewed-by: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
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>
Currently, Windows stacks are either 128kB or 2MB depending on whether
the binary uses cgo. This is because we assume that Go system stacks
and the small amount of C code invoked by the standard library can
operate within smaller stacks, but general Windows C code assumes
larger stacks.
However, it's easy to call into arbitrary C code using the syscall
package on Windows without ever importing cgo into a binary. Such
binaries need larger system stacks even though they don't use cgo.
Fix this on 64-bit by increasing the system stack size to 2MB always.
This only costs address space, which is free enough on 64-bit to not
worry about. We keep (for now) the existing heuristic on 32-bit, where
address space comes at more of a premium.
Updates #20975.
Change-Id: Iaaaa9a2fcbadc825cddc797aaaea8d34ef8debf2
Reviewed-on: https://go-review.googlesource.com/49331
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
ld.addpltsym adds an R_X86_64_JMP_SLOT dynamic relocation to .rela.plt
and uses Addaddrplus to reference the GOT in Elf64_Rela.r_offset.
Addaddrplus results in an R_ADDR relocation, which here we transform
into an R_X86_64_64 dynamic relocation. This is wrong for several
reasons:
1. .rela.plt is not a writable, relro section. It is mapped read-only,
causing the dynamic linker to segfault when it tried to handle the
relocation. This was the immediate cause of internal PIE cgo
crashes.
2. Relocations targetting other reloc sections are, as far as I can
tell, undefined behavior in the ELF spec and are unlikely to be a
good idea.
3. Even if the relocation did work, it isn't what we want. The
relocation, if successfully handled, would have put an absolute
address as the JMP_SLOT offset, but it should be the offset from the
beginning of the binary, just like any other relocation. What we want
is a statically resolved R_ADDR relocation, just as is used below for
the R_X86_64_64 relocation.
Skipping the .rela.plt allows reloc() to handle these R_ADDR
relocations.
With this CL, internal PIE cgo binaries work.
Updates #18968
Change-Id: Ie74e6fe249e88150baa0e340b1cb128cf7f28673
Reviewed-on: https://go-review.googlesource.com/47837
Reviewed-by: Ian Lance Taylor <iant@golang.org>
When using golang on ppc64le there have been issues
when building executables that generate extremely large text
sections. This is due to the call instruction and the limitation
on the offset field, which is smaller than most platforms. If the
size of the call target offset is too big for the offset field in
the call instruction, then link errors can occur.
The original solution to this problem in golang was to split the
text section when it became too large, allowing the external (GNU)
linker to insert the necessary stub to handle the long call. That
worked fine until the another size limit for the program size was hit,
where a plt_branch was created instead of a long branch. In that case
the plt_branch code sequence expects r2 to contain the address of the
TOC, but when golang creates dynamic executables by default
(-buildmode=exe) r2 does not always contain the address of the TOC
and as a result when building programs that reach this extremely
large size, a runtime SEGV or SIGILL can occur due to branching to a bad
address.
When using internal linking, trampolines are generated to handle the
long calls but the text sections are not split. With this change,
text sections will still be split approrpriately with external linking
but if the buildmode being used does not maintain r2 as the TOC
addresses, then trampolines will be created for those calls.
Fixes#20497
Change-Id: If5400b0f86c2c08e106b332be6db0b259b07d93d
Reviewed-on: https://go-review.googlesource.com/45130
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
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>
Programs built from N libraries required O(N²) time to do the
deduplication checks, even if there were never any duplicates.
In most programs N is small enough not to worry, but this may
affect large programs.
Noticed by inspection, not any specific bug report.
Fixes#20578.
Change-Id: Ic4108f1058be39da990a79b1e0b8ce95fde44cef
Reviewed-on: https://go-review.googlesource.com/44852
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Replaced ../gc/reflect.c with
cmd/compile/internal/gc/reflect.go.
Fixes#20525
Change-Id: Ibafd36ea446ace5c677df27873a4bbf716a0a9bc
Reviewed-on: https://go-review.googlesource.com/44376
Reviewed-by: Ian Lance Taylor <iant@golang.org>
In preparation for CL 41770, upgrade .debug_info to DWARF4, and emit
DW_AT_frame_base on subprograms. This should make no semantic
difference.
Also fix a long-standing bug/inconsistency in puttattr: it didn't
add the addend to ref_addrs. Previously this didn't matter because it
was only used for types, but now it's used for section offsets into
symbols that have multiple entries.
RELNOTE=yes
Change-Id: Ib10654ac92edfa29c5167c44133648151d70cf76
Reviewed-on: https://go-review.googlesource.com/44210
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Change compiler and linker to emit DWARF lexical blocks in .debug_info
section when compiling with -N -l.
Version of debug_info is updated from DWARF v2 to DWARF v3 since
version 2 does not allow lexical blocks with discontinuous PC ranges.
Remaining open problems:
- scope information is removed from inlined functions
- variables records do not have DW_AT_start_scope attributes so a
variable will shadow other variables with the same name as soon as its
containing scope begins, even before its declaration.
Updates #6913.
Updates #12899.
Change-Id: Idc6808788512ea20e7e45bcf782453acb416fb49
Reviewed-on: https://go-review.googlesource.com/40095
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Second attempt to fix#14710.
CL 35272 already tried to fix this issue. But CL 35272 assumed
that runtime.epclntab type is STEXT, while it is actually SRODATA.
This CL uses Symbol.Sect.Seg to determine if symbol is part
of Segtext or Segdata.
Fixes#14710
Change-Id: Ic6b6f657555c87a64d2bc36cc4c07ab0591d00c4
Reviewed-on: https://go-review.googlesource.com/42390
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
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#20183Fixes#20218
Change-Id: I5369a4db3913226aef3d9bd6317446856b0a1c34
Reviewed-on: https://go-review.googlesource.com/43331
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This can make life easier for Delve (and other debuggers),
and can help them with bug reports.
Sample producer field (from objdump):
<48> DW_AT_producer : Go cmd/compile devel +8a59dbf41a Mon May 8 16:02:44 2017 -0400
Change-Id: I0605843c959b53a60a25a3b870aa8755bf5d5b13
Reviewed-on: https://go-review.googlesource.com/33588
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
In PPC64 ELF files, the st_other field indicates the number of
prologue instructions between the global and local entry points.
We add the instructions in the compiler and assembler if -shared is used.
We were assuming that the instructions were present when building a
c-archive or PIE or doing dynamic linking, on the assumption that those
are the cases where the go tool would be building with -shared.
That assumption fails when using some other tool, such as Bazel,
that does not necessarily use -shared in exactly the same way.
This CL records in the object file whether a symbol was compiled
with -shared (this will be the same for all symbols in a given compilation)
and uses that information when setting the st_other field.
Fixes#20290.
Change-Id: Ib2b77e16aef38824871102e3c244fcf04a86c6ea
Reviewed-on: https://go-review.googlesource.com/43051
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
