This CL updates the Go compiler so it generate SEH unwind info [1] as a
function auxiliary symbol when building for windows/amd64.
A follow up CL will teach the Go linker how to assemble these codes
into the PE .xdata section.
Updates #57302
[1] https://learn.microsoft.com/en-us/cpp/build/exception-handling-x64#struct-unwind_info
Change-Id: I40ae0437bfee326c1a67c2b5e1496f0bf3ecea17
Reviewed-on: https://go-review.googlesource.com/c/go/+/461749
Reviewed-by: Davis Goodin <dagood@microsoft.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
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Go programs can now use the //go:wasmimport module_name function_name
directive to import functions from the WebAssembly runtime.
For now, the directive is restricted to the runtime and syscall/js
packages.
* Derived from CL 350737
* Original work modified to work with changes to the IR conversion code.
* Modification of CL 350737 changes to fully exist in Unified IR path (emp)
* Original work modified to work with changes to the ABI configuration code.
* Fixes#38248
Co-authored-by: Vedant Roy <vroy101@gmail.com>
Co-authored-by: Richard Musiol <mail@richard-musiol.de>
Co-authored-by: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>
Change-Id: I740719735d91c306ac718a435a78e1ee9686bc16
Reviewed-on: https://go-review.googlesource.com/c/go/+/463018
TryBot-Result: Gopher Robot <gobot@golang.org>
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Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>
Reviewed-by: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>
Introduce a flag in the object file indicating whether a given
function corresponds to a compiler-generated (not user-written) init
function, such as "os.init" or "syscall.init". Add code to the
compiler to fill in the correct value for the flag, and add support to
the loader package in the linker for testing the flag. The new loader
API is currently unused, but will be needed in the next CL in this
stack.
Updates #2559.
Updates #36021.
Updates #14840.
Change-Id: Iea7ad2adda487e4af7a44f062f9817977c53b394
Reviewed-on: https://go-review.googlesource.com/c/go/+/463855
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Run-TryBot: Than McIntosh <thanm@google.com>
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This is the second round to look for spelling mistakes. This time the
manual sifting of the result list was made easier by filtering out
capitalized and camelcase words.
grep -r --include '*.go' -E '^// .*$' . | aspell list | grep -E -x '[A-Za-z]{1}[a-z]*' | sort | uniq
This PR will be imported into Gerrit with the title and first
comment (this text) used to generate the subject and body of
the Gerrit change.
Change-Id: Ie8a2092aaa7e1f051aa90f03dbaf2b9aaf5664a9
GitHub-Last-Rev: fc2bd6e0c5
GitHub-Pull-Request: golang/go#57737
Reviewed-on: https://go-review.googlesource.com/c/go/+/461595
Auto-Submit: Ian Lance Taylor <iant@google.com>
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Reviewed-by: Robert Griesemer <gri@google.com>
Make linkgetlineFromPos and getFileIndexAndLine methods on Link, and
give the former a more descriptive name.
The docs are expanded to make it more clear that these are final
file/line visible in programs.
In getFileSymbolAndLine use ctxt.InnermostPos instead of ctxt.PosTable
direct, which makes it more clear that we want the semantics of
InnermostPos.
Change-Id: I7c3d344dec60407fa54b191be8a09c117cb87dd0
Reviewed-on: https://go-review.googlesource.com/c/go/+/446301
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
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This adds the function "start line number" to runtime._func and
runtime.inlinedCall objects. The "start line number" is the line number
of the func keyword or TEXT directive for assembly.
Subtracting the start line number from PC line number provides the
relative line offset of a PC from the the start of the function. This
helps with source stability by allowing code above the function to move
without invalidating samples within the function.
Encoding start line rather than relative lines directly is convenient
because the pprof format already contains a start line field.
This CL uses a straightforward encoding of explictly including a start
line field in every _func and inlinedCall. It is possible that we could
compress this further in the future. e.g., functions with a prologue
usually have <line of PC 0> == <start line>. In runtime.test, 95% of
functions have <line of PC 0> == <start line>.
According to bent, this is geomean +0.83% binary size vs master and
-0.31% binary size vs 1.19.
Note that //line directives can change the file and line numbers
arbitrarily. The encoded start line is as adjusted by //line directives.
Since this can change in the middle of a function, `line - start line`
offset calculations may not be meaningful if //line directives are in
use.
For #55022.
Change-Id: Iaabbc6dd4f85ffdda294266ef982ae838cc692f6
Reviewed-on: https://go-review.googlesource.com/c/go/+/429638
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[This is a retry of CL 407036 + its revert CL 422394. The only
content change is the 1-line change in cmd/internal/obj/objfile.go.]
Read the bitmaps one uintptr at a time instead of one byte at a time.
Performance so far:
Allocation heavy, no retention: ~30% faster in heapBitsSetType
Scan heavy, ~no allocation: ~even in scanobject
Change-Id: I04d899e1dbd23e989e9f552cdc1880318779c14c
Reviewed-on: https://go-review.googlesource.com/c/go/+/422635
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The length of slice hashedsyms is always 0, because it's not used after defined
Change-Id: Iba8e263aedfa403d5688678a1b37c2be3119eb7f
GitHub-Last-Rev: c236c4a482
GitHub-Pull-Request: golang/go#53450
Reviewed-on: https://go-review.googlesource.com/c/go/+/413234
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As it can't appear in user package paths.
There is a hack for handling "go:buildid" and "type:*" on windows/386.
Previously, windows/386 requires underscore prefix on external symbols,
but that's only applied for SHOSTOBJ/SUNDEFEXT or cgo export symbols.
"go.buildid" is STEXT, "type.*" is STYPE, thus they are not prefixed
with underscore.
In external linking mode, the external linker can't resolve them as
external symbols. But we are lucky that they have "." in their name,
so the external linker see them as Forwarder RVA exports. See:
- https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#export-address-table
- https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/pe-dll.c;h=e7b82ba6ffadf74dc1b9ee71dc13d48336941e51;hb=HEAD#l972)
This CL changes "." to ":" in symbols name, so theses symbols can not be
found by external linker anymore. So a hacky way is adding the
underscore prefix for these 2 symbols. I don't have enough knowledge to
verify whether adding the underscore for all STEXT/STYPE symbols are
fine, even if it could be, that would be done in future CL.
Fixes#37762
Change-Id: I92eaaf24c0820926a36e0530fdb07b07af1fcc35
Reviewed-on: https://go-review.googlesource.com/c/go/+/317917
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CL 391014 requires the compiler to be invoked with the -p flag, to
specify the package path. Later, CL 394217 makes the compiler to
produce an unlinkable object file, so "go tool compile x.go" can
still be used on the command line. This CL does the same for the
assembler, requiring -p, otherwise generating an unlinkable object.
No special case for the main package, as the main package cannot
be only assembly code, and there is no way to tell if it is the
main package from an assembly file.
Now we guarantee that we always have an expanded package path in
the object file. A later CL will delete the name expansion code
in the linker.
Change-Id: I8c10661aaea2ff794614924ead958d80e7e2487d
Reviewed-on: https://go-review.googlesource.com/c/go/+/404298
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The Go object file references (some of) symbols from other
packages by indices, not by names. The linker doesn't need the
symbol names to do the linking. The names are included in the
object file so it is self-contained and tools (objdump, nm) can
read the referenced symbol names. Including the names increases
object file size. Add a flag to disable it on demand (off by
default).
Change-Id: I143a0eb656997497c750b8eb1541341b2aee8f30
Reviewed-on: https://go-review.googlesource.com/c/go/+/404297
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When we add GOEXPERIMENT=boringcrypto, the bootstrap process
will not converge if the compiler itself depends on the boringcrypto
cgo-based implementations of sha1 and sha256.
Using notsha256 avoids boringcrypto and makes bootstrap converge.
Removing md5 is not strictly necessary but it seemed worthwhile to
be consistent.
For #51940.
Change-Id: Iba649507e0964d1a49a1d16e463dd23c4e348f14
Reviewed-on: https://go-review.googlesource.com/c/go/+/402595
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Change-Id: I46543e188bf25384e529a9d5a3095033ac618bbd
Reviewed-on: https://go-review.googlesource.com/c/go/+/402057
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[This CL is part of a sequence implementing the proposal #51082.
The design doc is at https://go.dev/s/godocfmt-design.]
Run the updated gofmt, which reformats doc comments,
on the main repository. Vendored files are excluded.
For #51082.
Change-Id: I7332f099b60f716295fb34719c98c04eb1a85407
Reviewed-on: https://go-review.googlesource.com/c/go/+/384268
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
A run of lines that are indented with any number of spaces or tabs
format as a <pre> block. This commit fixes various doc comments
that format badly according to that (standard) rule.
For example, consider:
// - List item.
// Second line.
// - Another item.
Because the - lines are unindented, this is actually two paragraphs
separated by a one-line <pre> block. This CL rewrites it to:
// - List item.
// Second line.
// - Another item.
Today, that will format as a single <pre> block.
In a future release, we hope to format it as a bulleted list.
Various other minor fixes as well, all in preparation for reformatting.
For #51082.
Change-Id: I95cf06040d4186830e571cd50148be3bf8daf189
Reviewed-on: https://go-review.googlesource.com/c/go/+/384257
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At least on some platforms (e.g. PE dynamic loader) relocations
need to be sorted in address order. Currently we don't always emit
relocations in address order: e.g. for array literal with out-of-
order element initializers, or out-of-order DATA instructions in
assembly code. Sort them.
No test for now as I can't reproduce the failure for #51923.
Fixes#51923.
Change-Id: Ifec5d3476e027bb927bcefd6e45c40ebeccee4ba
Reviewed-on: https://go-review.googlesource.com/c/go/+/396195
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CL 391014 requires the compiler to be invoked with the -p flag, to
specify the package path. People are used to run "go tool compile"
from the command line with the -p flag. This is mostly for simple
testing, or debugging the compiler. The produced object file is
almost never intended to be linked.
This CL makes the compiler allow "go tool compile" without the -p
flag again. It will produce an unlinkable object. If the linker
sees such an object it will error out.
Change-Id: I7bdb162c3cad61dadd5c456d903b92493a3df20f
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With the switch to the register ABI, we now generate wrapper
functions for go statements in many cases. A new goroutine's start
PC now points to the wrapper function. This does not affect
execution, but the runtime tracer uses the start PC and the
function name as the name/label of that goroutine. If the start
function is a named function, using the name of the wrapper loses
that information. Furthur, the tracer's goroutine view groups
goroutines by start PC. For multiple go statements with the same
callee, they are grouped together. With the wrappers, which is
context-dependent as it is a closure, they are no longer grouped.
This CL fixes the problem by providing the underlying unwrapped
PC for tracing. The compiler emits metadata to link the unwrapped
PC to the wrapper function. And the runtime reads that metadata
and record that unwrapped PC for tracing.
(This doesn't work for shared buildmode. Unfortunate.)
TODO: is there a way to test?
Fixes#50622.
Change-Id: Iaa20e1b544111c0255eb0fc04427aab7a5e3b877
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Currently, for stack traces (e.g. at panic or when runtime.Stack
is called), we print argument values from the stack. With register
ABI, we may never store the argument to stack therefore the
argument value on stack may be meaningless. This causes confusion.
This CL makes the compiler keep trace of which argument stack
slots are meaningful. If it is meaningful, it will be printed in
stack traces as before. If it may not be meaningful, it will be
printed as the stack value with a question mark ("?"). In general,
the value could be meaningful on some code paths but not others
depending on the execution, and the compiler couldn't know
statically, so we still print the stack value, instead of not
printing it at all. Also note that if the argument variable is
updated in the function body the printed value may be stale (like
before register ABI) but still considered meaningful.
Arguments passed on stack are always meaningful therefore always
printed without a question mark. Results are never printed, as
before.
(Due to a bug in the compiler we sometimes don't spill args into
their dedicated spill slots (as we should), causing it having
fewer meaningful values than it should be.)
This increases binary sizes a bit:
old new
hello 1129760 1142080 +1.09%
cmd/go 13932320 14088016 +1.12%
cmd/link 6267696 6329168 +0.98%
Fixes#45728.
Change-Id: I308a0402e5c5ab94ca0953f8bd85a56acd28f58c
Reviewed-on: https://go-review.googlesource.com/c/go/+/352057
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Insert machine NOPs when a prefixed instruction crosses a 64B boundary.
ISA 3.1 prohibits prefixed instructions being placed across them. Such
instructions generate SIGILL if executed.
Likewise, adjust the function alignment to guarantee such instructions
can never cross one. And, don't pad the PC based on alignment. The
linker can fit these more optimally.
Likewise, include the function alignment when printing function debug
information. This is needed to verify function alignment happens.
Updates #44549
Change-Id: I434fb0ee4e984ca00dc4566f7569c3bcdf93f910
Reviewed-on: https://go-review.googlesource.com/c/go/+/347050
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This change moves all symbols referred to by FUNCDATA
into go.func.* and go.funcrel.*.
Surprisingly (because it inhibits some content-addressability),
it shrinks binaries by a little bit, about 0.1%.
This paves the way for a subsequent change to change
FUNCDATA relocations to offsets.
Change-Id: I70e487205073699f442192b0791cc92da5663057
Reviewed-on: https://go-review.googlesource.com/c/go/+/352189
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runtime.gcbits symbols are pointer masks, which are just bytes.
Change-Id: I6e86359451c7da69da435e1928e55712dd904047
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Change-Id: I827a9702dfa01b712b88331668434f8db94df249
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There's no good way to ascertain at runtime whether
a function was implemented in assembly.
The existing workaround doesn't play nicely
with some upcoming linker changes.
This change introduces an explicit marker for routines
implemented in assembly.
This change doesn't use the new bit anywhere,
it only introduces it.
Change-Id: I4051dc0afc15b260724a04b9d18aeeb94911bb29
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FUNCDATA is always a symbol reference with 0 offset. Assert the
offset is 0 and remove funcdataoff.
Change-Id: I326815365c9db5aeef6b869df5d78a9957bc16a6
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Pcdata are now separate aux symbols. Read them from aux, instead
of using funcinfo.
Now we can remove pcdata fields from funcinfo.
Change-Id: Ie65e3962edecc0f39127a5f6963dc59d1f141e67
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When writing an object file, most symbols are indexed in
NumberSyms. Currently, pcdata symbols are indexed late and
separately. This is not really necessary, as pcdata symbols
already exist at the time of NumberSyms. Just do it there.
As pcdata symbols are laid out in the pclntab in a special way at
link time, distinguish them from other symbols in the content
hash. (In the old code this was partly achieved by indexing them
late.)
Change-Id: Ie9e721382b0af2cfb39350d031e2e66d79095a3c
Reviewed-on: https://go-review.googlesource.com/c/go/+/352611
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The goal of this change is to improve the documentation
and make it easier to keep Link.NumberSyms and writer.contentHash aligned.
No functional changes.
A subsequent change will add conditions to contentHashSection.
Change-Id: I0a274f6974459d34d5a8553081f33ea4cd87f248
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As of CL 247399 we use separate symbols for PCDATA. There is no
more need for writing PCDATA directly into the object file as a
separate block.
Change-Id: I942d1a372540415e0cc07fb2a01f79718a264142
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Create constant LocalDictName for the pname/refix for dictionary
parameters or local variables, and constant GlobalDictPrefix for the
prefix for names of global dictionaries. I wanted to make sure these
constants were set up as we add more reference to dictionaries for
debugging, etc.
Change-Id: Ide801f842383300a2699c96943ec06decaecc358
Reviewed-on: https://go-review.googlesource.com/c/go/+/351450
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Generate debug_info entries for types that are only referenced through
dictionaries.
Change-Id: Ic36c2e6d9588ec6746793bb213c2dc0e17a8a850
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Still 1-1 with real types, but now with their own names!
Shape types are implicitly convertible to (and convertible from)
the types they represent.
Change-Id: I0133a8d8fbeb369380574b075a32b3c987e314d5
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Currently, relocation type is stored as uint8 in object files, as
Go relocations do not exceed 255. In the linker, however, it is
used as a 16-bit type, because external relocations can exceed
255. The linker has to store the extra byte in a side table. This
complicates many things.
Just store it as uint16 in object files. This simplifies things,
with a small cost of increasing the object file sizes.
before after
hello.o 1672 1678
runtime.a 7927784 8056194
Change-Id: I313cf44ad0b8b3b76e35055ae55d911ff35e3158
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Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
The runtime traceback code has its own definition of which functions
mark the top frame of a stack, separate from the TOPFRAME bits that
exist in the assembly and are passed along in DWARF information.
It's error-prone and redundant to have two different sources of truth.
This CL provides the actual TOPFRAME bits to the runtime, so that
the runtime can use those bits instead of reinventing its own category.
This CL also adds a new bit, SPWRITE, which marks functions that
write directly to SP (anything but adding and subtracting constants).
Such functions must stop a traceback, because the traceback has no
way to rederive the SP on entry. Again, the runtime has its own definition
which is mostly correct, but also missing some functions. During ordinary
goroutine context switches, such functions do not appear on the stack,
so the incompleteness in the runtime usually doesn't matter.
But profiling signals can arrive at any moment, and the runtime may
crash during traceback if it attempts to unwind an SP-writing frame
and gets out-of-sync with the actual stack. The runtime contains code
to try to detect likely candidates but again it is incomplete.
Deriving the SPWRITE bit automatically from the actual assembly code
provides the complete truth, and passing it to the runtime lets the
runtime use it.
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: I227f53b23ac5b3dabfcc5e8ee3f00df4e113cf58
Reviewed-on: https://go-review.googlesource.com/c/go/+/288800
Trust: Russ Cox <rsc@golang.org>
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit contains the compiler support for //go:embed lines.
The go command passes to the compiler an "embed config"
that maps literal patterns like *.txt to the set of files to embed.
The compiler then lays out the content of those files as static data
in the form of an embed.Files or string or []byte in the final object file.
The test for this code is the end-to-end test hooking up the
embed, cmd/compile, and cmd/go changes, in the next CL.
For #41191.
Change-Id: I916e57f8cc65871dc0044c13d3f90c252a3fe1bf
Reviewed-on: https://go-review.googlesource.com/c/go/+/243944
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
We never supported symbol larger than 2GB (issue #9862), so the
object file uses 32-bit for symbol sizes. Check and reject too
large symbol before truncating its size.
Fixes#42054.
Change-Id: I0d1d585ebdba9556f2fd3a97043bd4296d5cc9e4
Reviewed-on: https://go-review.googlesource.com/c/go/+/263641
Trust: Cherry Zhang <cherryyz@google.com>
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
This creates space for a different kind of extension field
in LSym without making the struct any larger.
(There are many LSym, so we care about keeping the struct small.)
Change-Id: Ib16edb9e15f54c2a7351c8b875e19684058711e5
Reviewed-on: https://go-review.googlesource.com/c/go/+/243943
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2 conflicts, that make sense.
src/cmd/internal/obj/objfile.go
src/cmd/link/internal/loader/loader.go
Change-Id: Ib224e2d248cb568fa1e888af79dd908b2f5e05ff
Type namedata symbols are for type/field/method names and package
paths. We can use content-addressable symbol mechanism for them.
Change-Id: I923fda17b7094c7a0e46aad7c450622eb3826294
Reviewed-on: https://go-review.googlesource.com/c/go/+/257960
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
In CL 255718 the -S=2 assembly output was enhanced to dump symbol
ABIs. This patch fixes a bug in that CL: when dumping the relocations
on a symbol, we were dumping the symbol's ABI as opposed to the
relocation target symbol's ABI.
Change-Id: I134128687757f549fa37b998cff1290765889140
Reviewed-on: https://go-review.googlesource.com/c/go/+/257202
Trust: Than McIntosh <thanm@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
When -S=2 is in effect for the compiler/assembler, include symbol ABI
values for defined symbols and relocations. This is intended to help
make it easier to distinguish between a symbol and its ABI wrapper.
Change-Id: Ifbf71372392075f15363b40e882b2132406b7d6d
Reviewed-on: https://go-review.googlesource.com/c/go/+/255718
Trust: Than McIntosh <thanm@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
Switch pcdata over to content addressable symbols. This is the last
step before removing these from pclntab_old.
No meaningful benchmarks changes come from this work.
Change-Id: I3f74f3d6026a278babe437c8010e22992c92bd89
Reviewed-on: https://go-review.googlesource.com/c/go/+/247399
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
While working on deduplicating pcdata, I found that the following hashed
symbols would result in the same:
[] == [0,0,0,0....]
This makes using content addressable symbols untenable for pcdata.
Adding the length to the hash keeps the dream alive.
No difference in binary size (darwin, cmd/compile), spurious
improvements in DWARF phase memory.
Change-Id: I21101f7754a3d870922b0dea39c947cc8509432f
Reviewed-on: https://go-review.googlesource.com/c/go/+/247903
Run-TryBot: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Combine objfile2.go into objfile.go.
objfile.go has a lot of code for DWARF generation. Move them to
dwarf.go.
Change-Id: I2a27c672e9e9b8eea35d5e0a71433dcc80b7afa4
Reviewed-on: https://go-review.googlesource.com/c/go/+/247918
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Leaving creation of the funcID till the linker requires the linker to
load the function and file names into memory. Moving these into the
compiler/assembler prevents this.
This work is a step towards moving all func metadata into the compiler.
Change-Id: Iebffdc5a909adbd03ac263fde3f4c3d492fb1eac
Reviewed-on: https://go-review.googlesource.com/c/go/+/244024
Run-TryBot: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Austin Clements <austin@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>
