Rework the way symbols are handled in DWARF line table generation to
eliminate copying the data payload for all SWDWARFLINES syms (emitted
by the compiler) into the payload of the ".debug_line" section symbol
(generated by the linker). Instead, chain together the SWDWARFLINES
symbols into a list, then append that list to the section sym list in
dwarfp (this moves us from a single monolithic .debug_line to a
.debug_line section sym followed by a list symbols (one per function
and an epilog symbol per compilation unit). To enable this work, move
the emission of the DW_LNE_set_address op (at the start of each
function) from the linker to the compiler.
Change-Id: Iec61b44a451f7a386c82a89bf944de482b018789
Reviewed-on: https://go-review.googlesource.com/c/go/+/237427
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Don't emit the .debug_pubnames/.debug_pubtypes sections. These sections
are not used by either GDB or Delve, and C++ compilers [notably GCC
and Clang] no longer emit the sections by default.
Change-Id: Ic3309755e88c8e1aa28a29366bc7f0df1748fe64
Reviewed-on: https://go-review.googlesource.com/c/go/+/237426
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Relocate the last few functions in dwarf2.go to dwarf.go,
and remove dwarf2.go. No change in functionality.
Change-Id: Id1b5f0d1c496d5912b955b8ba942e33bc43aa93b
Reviewed-on: https://go-review.googlesource.com/c/go/+/237425
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Merge conflicts are mostly recently changed nm/objdump output
format and its tests. Resolved easily (mostly just using the
format on master branch).
Change-Id: I99d8410a9a02947ecf027d9cae5762861562baf5
During DWARF line table emission in the linker, prior to issuing a
DW_LNE_end_sequence op to mark the end of the line table for a
compilation unit, advance the PC to produce an address beyond the last
text address in the unit (this is required by the DWARF standard).
Because of the way that GDB interprets end-sequence ops, we were
effectively losing the last row in the line table for each unit, which
degraded the debugging experience.
This problem has been around for a while, but has surfaced recently
due to changes in line table generation. Prior to Go 1.14, the DWARF
line table was emitted entirely in the linker, and a single monolithic
line table was created for each Go package (including functions from
assembly). In 1.14 we moved to having the compiler emit line table
fragments for each function, and having the linker stitch together the
fragments. As part of this change we moved to a model in which each
"go tool compile/asm" output has its own DWARF line table instance,
meaning that there are many more "end sequence" ops, which made the
problem more visible.
Fixes#38192.
Change-Id: Ic29e2f6e0ac952360c81fcba5268ad70b2b44184
Reviewed-on: https://go-review.googlesource.com/c/go/+/235739
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Rework the code in the linker that visits DWARF subprorgam DIEs to
reduce number of symbol name instantiations and name lookups, by
making better use of relocation target symbol types.
Change-Id: Ifb2a4e24874b8c891d7fdf17dd749c3f9139157a
Reviewed-on: https://go-review.googlesource.com/c/go/+/234685
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This change splits the SDWARFINFO symbol type (a generic container of
DWARF content) into separate sub-classes. The new symbol types are
SDWARFCUINFO comp unit DIE, also CU info and CU packagename syms
SDWARFCONST constant DIE
SDWARFFCN subprogram DIE (default and concrete)
SDWARFABSFCN abstract function DIE
SDWARFTYPE type DIE
SDWARFVAR global variable DIE
Advantage of doing this: in the linker there are several places where
we have to iterate over a symbol's relocations to pick out references
to specific classes of DWARF sub-symbols (for example, looking for all
abstract function DIEs referenced by a subprogram DIE, or looking at
all the type DIEs used in a subprogram DIE). By splitting SDWARFINFO
into parts clients can now look only at the relocation target's sym
type as opposed to having to materialize the target sym name, or do a
lookup.
Change-Id: I4e0ee3216d3c8f1a78bec3d296c01e95b3d025b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/234684
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
This patch converts the linker's Asmb2 phase to use loader APIs
for AMD64 (other architectures to be converted in a subsequent
patch).
Change-Id: I5a9aa9b03769cabc1a22b982f48fd113213d7bcf
Reviewed-on: https://go-review.googlesource.com/c/go/+/233338
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
And remove "2" from some function names.
Change-Id: Ibf1089970d849a42f53976064ceb9ade20bf6eba
Reviewed-on: https://go-review.googlesource.com/c/go/+/231017
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Change linker DWARF generation to move away from emitting a single
giant list of DWARF symbols, and instead emit a list of descriptors,
with each descriptor holding the symbols for a specific DWARF section.
While placing all DWARF symbols in a single lists does come in handy
in certain instances, it also creates a lot of confusion and weird
code in other cases, specifically where we want to perform operations
on a section-by-section basis (resulting in code that tries to
re-discover section boundaries by walking/inspecting the list).
Change-Id: I4dac81bd38cba903c9fd7004d613597e76dfb77a
Reviewed-on: https://go-review.googlesource.com/c/go/+/228780
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
If we are internal linking a static executable, and address assignment
has happened, then when emitting some parts of DWARF we can just emit
a function address directly instead of generating a relocation. For
external linking or other build modes, we are generating a relocatable
binary so we still need to emit relocations.
This CL inspired by Cherry's similar CL for pclntab at
https://go-review.googlesource.com/c/go/+/228478.
Change-Id: Ib03fbe2dd72d0ba746bf46015e0f2d6c3f3d53ab
Reviewed-on: https://go-review.googlesource.com/c/go/+/228537
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Hoist dwarfGenerateDebugSyms call up out of dodata to before
loadlibfull. This required a couple of small tweaks to the
loader and to loadlibfull.
Change-Id: I48ffb450d2e48b9e55775b73a6debcd27dbb7b9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/228221
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
SymFile, derived from sym.Symbol.File, is supposed to return the
package path, instead of the file name (arguably the name is
confusing). Make it so, and rename it to SymPkg.
Change-Id: I67bcd12f67cea271f2a2ce3c5724e5d228f5b2f0
Reviewed-on: https://go-review.googlesource.com/c/go/+/227481
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
The Count field in Relocs type is always equal to len(rs). Unify
them.
Change-Id: Ic77288ea58b61a98482b218e051d81047d0ddd88
Reviewed-on: https://go-review.googlesource.com/c/go/+/226717
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Store external relocations in (almost) the same format as the Go
objects, so we can handle them more uniformly.
There is a small speedup:
(linking cmd/compile)
Deadcode 67.8ms ± 3% 61.1ms ± 3% -9.94% (p=0.008 n=5+5)
Dostkcheck 41.2ms ± 2% 38.8ms ± 3% -5.99% (p=0.008 n=5+5)
Change-Id: I8616e10b26235904201d6c9465f5ae32a49c9949
Reviewed-on: https://go-review.googlesource.com/c/go/+/226365
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Update PropagateLoaderChangesToSymbols so that it no longer requires
a sym.Symbols pointer. The intent is to generalize it a little to
allow it to be used in more than just linker Dwarf generation.
Change-Id: I9bddc5d39839eacd9113c945bb59d2873c0b088c
Reviewed-on: https://go-review.googlesource.com/c/go/+/224381
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
This patch moves the compiler and linker away from the current scheme
used to generate file references in DWARF subprogram dies.
Up until now the scheme has been to have the compiler emit a special
relocation on a DIE file reference that points to the file symbol in
question. The linker then reads this relocation and updates the addend
to the index of the appropriate file in the line table of the
compilation unit of the DIE (the linker emits the comp unit file
table, so it knows at that point what number use). The drawback of
this scheme is that it requires a lot of relocation processing.
With this patch, we switch to having the compiler emit the file index
directly, and then have the linker use the compiler-generated file
table to emit the line table file section (no renumbering, no
relocations, etc).
Change-Id: Id4fbe67b28a64200a083e3c5ea358dbe091ec917
Reviewed-on: https://go-review.googlesource.com/c/go/+/223318
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Switch the primary subprogram die DWARF symbol emitted by the compiler
from named+dupOK to anonymous aux. This should help performance wise
by not having to add these symbols to the linker's symbol name lookup
tables.
Change-Id: Idf66662b8bf60b3dee9a55e6cd5137b24a9f5ab6
Reviewed-on: https://go-review.googlesource.com/c/go/+/223669
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
They used to be different at some point, but now AddExtSym and
LookupOrCreateSym are identical. Remove one.
Change-Id: I299444d987e32a7f43915b3c1bbcc5ae906e9b6a
Reviewed-on: https://go-review.googlesource.com/c/go/+/223977
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
This gives some speedup and reduces some allocations:
(linking cmd/compile)
DwarfGenerateDebugInfo 63.2ms ± 3% 41.7ms ± 3% -34.04% (p=0.008 n=5+5)
DwarfGenerateDebugInfo 20.0MB ± 0% 10.1MB ± 0% -49.62% (p=0.008 n=5+5)
There are code that modify relocations, which are still using
the earlier loader.Reloc slice for now.
Change-Id: I3359ba305bf82cc882ae3c0f548d6ccfc8add789
Reviewed-on: https://go-review.googlesource.com/c/go/+/223663
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
When the compiler emits DWARF for a function F, in addition to the
text symbol for F, it emits a set of sibling or child symbols that
carry the various DWARF bits for F (for example, go.info.F,
go.ranges.F, go.loc.F, and so on).
Prior to the linker modernization work, name lookup was the way you
made your way from a function symbol to one of its child DWARF
symbols. We now have a new mechanism (aux symbols), so there is really
no need for the DWARF sub-symbols to be named or to be dupok.
This patch converts DWARF "range" and "loc" sub-symbols to be pure aux
syms: unnamed, and connected to their parent text symbol only via aux
data. This should presumably have performance benefits in that we add
fewer symbols to the linker lookup tables.
Other related DWARF sub-symbols (ex: go.line.*) will be handled in a
subsequent patch.
Change-Id: Iae3ec2d42452962d4afc1df4a1bd89ccdeadc6e4
Reviewed-on: https://go-review.googlesource.com/c/go/+/222673
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The linker DWARF-gen's line table writing routine contains a loop that
walks all abstract function DIEs looking for files that aren't
referenced in concrete function DIEs. Turns out this loop is no longer
necessary, most likely because the compiler emits an explicit DWARF
file table into the object file.
This patch removes the offending loop. This is a prelude to some
additional work that will hopefully get rid of file renumbering in
writelines altogether (still WIP).
Change-Id: I3b3a9acce1bae7dda878ab6de2d3436de302712e
Reviewed-on: https://go-review.googlesource.com/c/go/+/223145
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Remove the various bits of code in the linker that patch DWARF name
attributes (rewrite "". to packagepath).
Change-Id: I29a38d680d411ccf1c1eeb760f2d15fc8ec22d90
Reviewed-on: https://go-review.googlesource.com/c/go/+/222719
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Remove the temporary "-newdw2" linker command line option, along with
the remainder of the legacy sym.Symbol based DWARF generation code.
Change-Id: I86c0581dd021cd4e2209ca9bc45f34037d42323c
Reviewed-on: https://go-review.googlesource.com/c/go/+/222766
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Move to a shared/reused slice of loader.Reloc's in a couple of places
in the linker's DWARF writelines method, as opposed to allocating a
new slice each time. Small performance improvement.
Change-Id: I06c64cf7ca00162d24d9421f1d6405c8808ebb83
Reviewed-on: https://go-review.googlesource.com/c/go/+/222758
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
In a couple of places in the DWARF type generation code there were
calls to the older sym.Symbol "newdie" funtion as opposed to the
loader.Sym based method. This patch converts these to method calls.
Change-Id: I202957464b7c37063ff74e834ed7b76d1dc5bcdf
Reviewed-on: https://go-review.googlesource.com/c/go/+/222757
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This converts the second portion of DWARF-gen (dwarfGenerateDebugSyms
function and friends) to use the loader, as opposed to sym.Symbols.
Second phase is invoked as part of dodata(), which is fairly far along
in the linker, meaning that the "converted to loader.Symbol" wavefront
has not yet reached that point.
To account for this, the patch contains some shim code that runs
initially to copy back things from sym.Symbols into the loader
(notable symbol values), and then a second hook to be code after
dwarf-gen is complete to that copies the results back into the
appropriate sym.Symbols. This code is obviously temporary, but needed
for the time being.
Change-Id: I9b830b08b16480a1a5230cb52b592db1c550af18
Reviewed-on: https://go-review.googlesource.com/c/go/+/220987
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Change the loader method AssignTextSymbolOrder to return a slice of
all reachable textp symbols, since it will be needed in second-phase
DWARF gen.
Change-Id: Iaf16ee9cf0d5266aeb0d3df596e8117263b35d8e
Reviewed-on: https://go-review.googlesource.com/c/go/+/220985
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Remove the "-newdw" command line option, a temporary placeholder/gate
for the first phase of new DWARF gen, along with some portions of the
sym.Symbol based DWARF type gen code. The remainder of the old code
will be removed in a subsequent patch.
Change-Id: I7870539f020fbf05d0345d3af2acf383fae94892
Reviewed-on: https://go-review.googlesource.com/c/go/+/220984
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Get rid of of the linker's dwSym struct (which wraps a loader.Loader
and a loader.Sym) in favor of just loader.Sym. This requires some minor
tweaks to the cmd/internal/dwarf interfaces.
Change-Id: Id3ffd7c41b2433ea04417040368700334bb0e611
Reviewed-on: https://go-review.googlesource.com/c/go/+/220982
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Converts the portion of DWARF generation that deals with creation of
type DIEs and constant DIEs to use the new loader interfaces. Creation
of subprogram DIE and compilation unit DIE content still operates on
sym.Symbols at the moment, and happens much later in the linker.
The new code for type DIE generation is gated/guarded by the linker
flag "-newdw", which currently defaults to true. At some point in the
near future this flag should be removed, but it is handy for triage at
the moment.
This patch also includes shim code designed to run after loadlibfull()
that walks through the DIE chains and to converts loader.Sym
references back into sym.Symbol references for the remainder of the
compilation, since the second phase of DWARF has not yet been
converted.
Change-Id: I681a00fb8a1f3c37884a79b373d86411332e07c8
Reviewed-on: https://go-review.googlesource.com/c/go/+/208230
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Assorted fixups in the linker needed to enable turning back on
DWARF generation when building plugins for Darwin. Includes:
- don't suppress import of runtime/cgo in the linker for
Darwin if we are linking in plugin mode
- in calcCompUnitRanges handle the case where we encounter
linker-generated functions that have no associated Unit (and
also have no DWARF)
- generalize a guard in relocsym() include so as to avoid
triggering a spurious error on go.info symbols in plugin mode
Updates #21647.
Updates #27502.
Change-Id: I317fea97bef2f3461e31498e63f9fd6d8b8f4b23
Reviewed-on: https://go-review.googlesource.com/c/go/+/182959
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Also a similar 'elapsed' function and its usages were deleted.
Fixes#19865.
Change-Id: Ib125365e69cf2eda60de64fa74290c8c7d1fd65a
Reviewed-on: https://go-review.googlesource.com/c/go/+/171730
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Change some decodetype functions to operate on bytes nstead of
Symbol. This is in preparation of implementing live method
tracking in index-based deadcode pass, and reducing/eliminating
sym.Symbol in general.
Change-Id: Ia9809ad7b182884225e1bda577e8dbec0cd216c5
Reviewed-on: https://go-review.googlesource.com/c/go/+/199077
Reviewed-by: Austin Clements <austin@google.com>
Switch the linker over to use dummy R_USETYPE relocations on DWARF
subprogram DIEs as a means of insuring that DWARF types are created
for types of autotmp values used in live functions.
This change is part of a series intended to clean up handling of
autotmp types and remove use of autom's in the compiler and linker.
Updates #34554.
Change-Id: Ic74da6bd723ab7e4d8a16ad46e23228650d4b525
Reviewed-on: https://go-review.googlesource.com/c/go/+/197498
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
This switches the linker over to using the new debug_lines data
generated in the compiler.
Change-Id: If8362d6fcea7db60aaebab670ed6f702ab1c4908
Reviewed-on: https://go-review.googlesource.com/c/go/+/191968
Run-TryBot: Jeremy Faller <jeremy@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
As we move the debug_line generation into the compiler, we need to
upgrade the notion of compilationUnit to not just be on a per package
basis. That won't be the case as it will be impossible for all
compilationUnits to have the same set of files names used to build the
debug_lines table. (For example, assembled files in a package don't know
about any files but themselves, so the debug_lines table could only
reference themseves. As such, we need to break the 1:1 relationship
between compUnit and package.)
Change-Id: I2e517bb6c01de0115bbf777af828a2fe59c09ce8
Reviewed-on: https://go-review.googlesource.com/c/go/+/189618
Run-TryBot: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
I'm branching this off cl/187117, and will be reworking that diff stack.
Testing: I've run go build -toolexec 'toolstash -cmp'
Change-Id: I922a97d0f25d52ea70cd974008a063d4e7af34a7
Reviewed-on: https://go-review.googlesource.com/c/go/+/188023
Reviewed-by: Austin Clements <austin@google.com>
This was originally
Revert "cmd/link: fix up debug_range for dsymutil (revert CL 72371)"
which has the effect of no longer using Base Address Selection
Entries in DWARF. However, the build-time costs of that are
about 2%, so instead the hacky fixup that generated technically
incorrect DWARF was removed from the linker, and the choice
is instead made in the compiler, dependent on platform, but
also under control of a flag so that we can report this bug
against LLDB/dsymutil/dwarfdump (really, the LLVM dwarf
libraries).
This however does not solve #31188; debugging still fails,
but dwarfdump no longer complains. There are at least two
LLDB bugs involved, and this change will at allow us
to report them without them being rejected because our
now-obsolete workaround for the first bug creates
not-quite-DWARF.
Updates #31188.
Change-Id: I5300c51ad202147bab7333329ebe961623d2b47d
Reviewed-on: https://go-review.googlesource.com/c/go/+/170638
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
We are preparing for applying relocations to the output buffer.
However, for DWARF compression, relocations need to be applied
before compression, but we don't have an output buffer at that
time. We also cannot delay DWARF compression to when we mmap the
output file, because we need the size of the DWARF sections to
compute the file size.
Instead of applying all the relocations together, we apply
relocations in DWARF sections one symbol at a time, right before
it is writing out for compression. As the symbol content may be
in read-only memory (in the future), we use a temporary buffer
for applying the relocations, and immediately write it out.
If compression is not used, relocations are still applied all
together.
This is in preparation for mmap'ing input files read-only.
Change-Id: Iae6d2dd71313897d5054bcc458d3bb78075b30c3
Reviewed-on: https://go-review.googlesource.com/c/go/+/171397
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Apply R_DWARFFILEREF relocations later, along with other
relocations, so that we don't modify symbols' contents before
they are written to the output buffer.
This is in preparation for mmap'ing input files read-only.
Change-Id: I8e9ffb2f05acf8f198589b8770f277beb3847541
Reviewed-on: https://go-review.googlesource.com/c/go/+/170740
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This CL adds a new attribute, TOPFRAME, which can be used to mark
functions that should be treated as being at the top of the call
stack. The function `runtime.goexit` has been marked this way on
architectures that use a link register.
This will stop programs that use DWARF to unwind the call stack
from unwinding past `runtime.goexit` on architectures that use a
link register. For example, it eliminates "corrupt stack?"
warnings when generating a backtrace that hits `runtime.goexit`
in GDB on s390x.
Similar code should be added for non-link-register architectures
(i.e. amd64, 386). They mark the top of the call stack slightly
differently to link register architectures so I haven't added
that code (they need to mark "rip" as undefined).
Fixes#24385.
Change-Id: I15b4c69ac75b491daa0acf0d981cb80eb06488de
Reviewed-on: https://go-review.googlesource.com/c/go/+/169726
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Rename it to PCIter and convert it to use methods.
Set pcscale once, during construction, to make call sites clearer.
Change some ints to bools.
Use a simple iteration termination condition,
instead of the cap comparison from the c2go translation.
Instead of requiring a Pcdata, which requires one caller
to synthesize a fake Pcdata, just ask for a byte slice.
Passes toolstash-check.
Change-Id: I811da0e929cf4a806bd6d70357ccf2911cd0c737
Reviewed-on: https://go-review.googlesource.com/c/go/+/171770
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Add a new custom attribute to compile units containing the package name
of the package (i.e. the name after the 'package' keyword), so that
debuggers can know it when it's different from the last segment
of the package path.
Change-Id: Ieadaab6f47091aabf2f4dc42c8524452eaa6715b
Reviewed-on: https://go-review.googlesource.com/c/go/+/163677
Run-TryBot: Alessandro Arzilli <alessandro.arzilli@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
