266 Commits

Author SHA1 Message Date
Cherry Mui
1cf6e31f0d cmd/compile: add basic wasmexport support
This CL adds a compiler directive go:wasmexport, which applies to
a Go function and makes it an exported function of the Wasm module
being built, so it can be called directly from the host. As
proposed in #65199, parameter and result types are limited to
32-bit and 64-bit integers and floats, and there can be at most
one result.

As the Go and Wasm calling conventions are different, for a
wasmexport function we generate a wrapper function does the ABI
conversion at compile time.

Currently this CL only adds basic support. In particular,
- it only supports executable mode, i.e. the Go wasm module calls
  into the host via wasmimport, which then calls back to Go via
  wasmexport. Library (c-shared) mode is not implemented yet.
- only supports wasip1, not js.
- if the exported function unwinds stacks (goroutine switch, stack
growth, etc.), it probably doesn't work.

TODO: support stack unwinding, c-shared mode, js.

For #65199.

Change-Id: Id1777c2d44f7d51942c1caed3173c0a82f120cc4
Reviewed-on: https://go-review.googlesource.com/c/go/+/603055
Reviewed-by: Than McIntosh <thanm@golang.org>
Reviewed-by: Randy Reddig <randy.reddig@fastly.com>
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2024-08-09 20:07:54 +00:00
Cherry Mui
03e5d83ca7 cmd/internal/obj: minor refactor of wasmimport code
This CL does some minor refactoring of the code handling
wasmimport.
- Put the WasmImport aux reading and writing code together for
  symmetry.
- Define WasmFuncType, embedded in WasmImport. WasmFuncType could
  also be used (later) for wasmexport.
- Move code generation code to a separate function. The containing
  function is already pretty large.
- Simplify linker code a little bit. The loader convention is to
  return the 0 Sym for nonexistent symbol, instead of a separate
  boolean.

No change in generated code. Passes toolstash -cmp
(GOARCH=wasm GOOS=wasip1 go build -toolexec "toolstash -cmp" -a std cmd).

Change-Id: Idc2514f84a08621333841ae4034b81130e0ce411
Reviewed-on: https://go-review.googlesource.com/c/go/+/603135
Reviewed-by: Than McIntosh <thanm@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
2024-08-06 15:56:16 +00:00
Cherry Mui
5c7d774538 cmd/link: propagate FromAssembly attribute when cloning symbols to external
When a symbol is cloned to external (in order to edit it),
propagate the FromAssembly attribute, so the linker knows it is
(originally) an assembly symbol, and can treat it specially (e.g.
for stack maps).

This should fix the Linux/RISCV64 builder.

Change-Id: Icc956bcc43b79f328983a60835b05fd50f22326a
Reviewed-on: https://go-review.googlesource.com/c/go/+/587926
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Than McIntosh <thanm@google.com>
2024-05-24 20:26:10 +00:00
Cherry Mui
c4772d30bf cmd/link: disallow pull-only linknames
As mentioned in CL 584598, linkname is a mechanism that, when
abused, can break API integrity and even safety of Go programs.
CL 584598 is a first step to restrict the use of linknames, by
implementing a blocklist. This CL takes a step further, tightening
up the restriction by allowing linkname references ("pull") only
when the definition side explicitly opts into it, by having a
linkname on the definition (possibly to itself). This way, it is at
least clear on the definition side that the symbol, despite being
unexported, is accessed outside of the package. Unexported symbols
without linkname can now be actually private. This is similar to
the symbol visibility rule used by gccgo for years (which defines
unexported non-linknamed symbols as C static symbols).

As there can be pull-only linknames in the wild that may be broken
by this change, we currently only enforce this rule for symbols
defined in the standard library. Push linknames are added in the
standard library to allow things build.

Linkname references to external (non-Go) symbols are still allowed,
as their visibility is controlled by the C symbol visibility rules
and enforced by the C (static or dynamic) linker.

Assembly symbols are treated similar to linknamed symbols.

This is controlled by -checklinkname linker flag, currently not
enabled by default. A follow-up CL will enable it by default.

Change-Id: I07344f5c7a02124dbbef0fbc8fec3b666a4b2b0e
Reviewed-on: https://go-review.googlesource.com/c/go/+/585358
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
2024-05-15 19:57:43 +00:00
Cherry Mui
4721f95058 cmd/compile, cmd/link: disallow linkname of some newly added internal functions
Go API is defined through exported symbols. When a package is
imported, the compiler ensures that only exported symbols can be
accessed, and the go command ensures that internal packages cannot
be imported. This ensures API integrity. But there is a hole:
using linkname, one can access internal or non-exported symbols.
Linkname is a mechanism to give access of a symbol to a package
without adding it to the public API. It is intended for coupled
packages to share some implementation details, or to break
circular dependencies, and both "push" (definition) and "pull"
(reference) sides are controlled, so they can be updated in sync.
Nevertheless, it is abused as a mechanism to reach into internal
details of other packages uncontrolled by the user, notably the
runtime. As the other package evolves, the code often breaks,
because the linknamed symbol may no longer exist, or change its
signature or semantics.

This CL adds a mechanism to enforce the integrity of linknames.
Generally, "push" linkname is allowed, as the package defining
the symbol explicitly opt in for access outside of the package.
"Pull" linkname is checked and only allowed in some circumstances.
Given that there are existing code that use "pull"-only linkname
to access other package's internals, disallowing it completely is
too much a change at this point in the release cycle. For a start,
implement a hard-coded blocklist, which contains some newly added
internal functions that, if used inappropriately, may break memory
safety or runtime integrity. All blocked symbols are newly added
in Go 1.23. So existing code that builds with Go 1.22 will
continue to build.

For the implementation, when compiling a package, we mark
linknamed symbols in the current package with an attribute. At
link time, marked linknamed symbols are checked against the
blocklist. Care is taken so it distinguishes a linkname reference
in the current package vs. a reference of a linkname from another
package and propagated to the current package (e.g. through
inlining or instantiation).

Symbol references in assembly code are similar to linknames, and
are treated similarly.

Change-Id: I8067efe29c122740cd4f1effd2dec2d839147d5d
Reviewed-on: https://go-review.googlesource.com/c/go/+/584598
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
2024-05-10 17:05:33 +00:00
Jeremy Quirke
c2c4a32f9e cmd/link: remove objIdx structure
This indirection appears to be unnecessary for linking or linker debugging, and therefore hinders readability.

Since all *oReaders are added to loader.objs *only* via the Preload -> addObj path, before any symbols are examined, there is no possible way the "i" member of this structure is still useful; and is likely a remnant of an earlier design.

Change-Id: Icd880f40bf3299bf1aa0a14cf217268e49ee90c5
GitHub-Last-Rev: dd2d512cbe99a551585fc9f895eca28a5bfde21b
GitHub-Pull-Request: golang/go#57460
Reviewed-on: https://go-review.googlesource.com/c/go/+/459456
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
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TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
2024-03-23 04:28:32 +00:00
Ville Skyttä
1d187fd0be src: a/an grammar fixes
Change-Id: I179b50ae8e73677d4d408b83424afbbfe6aa17a1
GitHub-Last-Rev: 2e2d9c1e45556155d02db4df381b99f2d1bc5c0e
GitHub-Pull-Request: golang/go#63478
Reviewed-on: https://go-review.googlesource.com/c/go/+/534015
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
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Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
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Reviewed-by: Michael Knyszek <mknyszek@google.com>
2023-11-20 15:56:08 +00:00
Than McIntosh
3f700ce4d2 cmd/link/internal/loader: remove some dead code
Get rid of a couple of unused methods in the loader and symbol
builder.

Change-Id: I3822891757dc56356295a9bc99545b725d485eac
Reviewed-on: https://go-review.googlesource.com/c/go/+/540260
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2023-11-08 15:25:19 +00:00
Matthew Dempsky
9b0140a695 cmd/link: type alias sym.LoaderSym and loader.Sym
Rather than making these two different types, we can type alias them
together. This will ease converting cmd/internal/dwarf to use generics
in a subsequent CL.

The one unfortunate quirk is that while we'd currently like loader.Sym
to be the authoritative type, to break the cycle we have to instead
make loader.Sym an alias of sym.LoaderSym.

Change-Id: I6dde0d492ca89a478c2470c426bb4eed3393d680
Reviewed-on: https://go-review.googlesource.com/c/go/+/525195
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2023-09-01 20:39:56 +00:00
Alexander Yastrebov
8ffc931eae all: fix spelling errors
Fix spelling errors discovered using https://github.com/codespell-project/codespell. Errors in data files and vendored packages are ignored.

Change-Id: I83c7818222f2eea69afbd270c15b7897678131dc
GitHub-Last-Rev: 3491615b1b82832cc0064f535786546e89aa6184
GitHub-Pull-Request: golang/go#60758
Reviewed-on: https://go-review.googlesource.com/c/go/+/502576
Auto-Submit: Michael Pratt <mpratt@google.com>
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2023-06-14 00:03:57 +00:00
cui fliter
39effbc105 all: fix function names in comments
Change-Id: I915eff34fcfe82f3514254f7d8998baa88a91da6
Reviewed-on: https://go-review.googlesource.com/c/go/+/501997
Reviewed-by: Ian Lance Taylor <iant@google.com>
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2023-06-09 04:07:29 +00:00
Cherry Mui
f90bb8a38f cmd/link: remove elfsetstring out of the loader
Currently, we pass elfsetstring to the loader as a callback, for
a special case of Addstring. This is only used for ELF when adding
strings to the section header string table. Move the logic to the
caller instead, so the loader would not have this special case.

Change-Id: Icfb91f380fe4ba435985c3019681597932f58242
Reviewed-on: https://go-review.googlesource.com/c/go/+/492718
Run-TryBot: Cherry Mui <cherryyz@google.com>
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2023-05-05 19:20:01 +00:00
Cherry Mui
630ef2edc2 cmd/link: remove allocation in decoding type name
The type name symbol is always from a Go object file and we never
change it. Convert the data to string using unsafe conversion
without allocation.

Linking cmd/go (on macOS/amd64),

name           old alloc/op   new alloc/op   delta
Deadcode_GC      1.25MB ± 0%    1.17MB ± 0%   -6.29%  (p=0.000 n=20+20)

name           old allocs/op  new allocs/op  delta
Deadcode_GC       8.98k ± 0%     0.10k ± 3%  -98.91%  (p=0.000 n=20+20)

Change-Id: I33117ad1f991e4f14ce0b38cceec50b041e3c0a4
Reviewed-on: https://go-review.googlesource.com/c/go/+/490915
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2023-05-02 17:29:09 +00:00
qmuntal
14cf82aa37 cmd/link: generate .pdata PE section
This CL adds a .pdata section to the PE file generated by the Go linker.

The .pdata section is a standard section [1] that contains an array of
function table entries that are used for stack unwinding.
The table entries layout is taken from [2].

This CL just generates the table entries without any unwinding
information, which is enough to start doing some E2E tests
between the Go linker and the Win32 APIs.

The goal of the .pdata table is to allow Windows retrieve
unwind information for a function at a given PC. It does so by doing
a binary search on the table, looking for an entry that meets
BeginAddress >= PC < EndAddress.

Each table entry takes 12 bytes and only non-leaf functions with
frame pointer needs an entry on the .pdata table.
The result is that PE binaries will be ~0.7% bigger due to the unwind
information, a reasonable amount considering the benefits in
debuggability.

Updates #57302

[1] https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#the-pdata-section
[2] https://learn.microsoft.com/en-us/cpp/build/exception-handling-x64#struct-runtime_function

Change-Id: If675d10c64452946dbab76709da20569651e3e9f
Reviewed-on: https://go-review.googlesource.com/c/go/+/461738
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Quim Muntal <quimmuntal@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
2023-05-02 07:42:50 +00:00
Cherry Mui
4e8c6af239 cmd/link, cmd/internal/obj: use aux symbol for global variable DWARF info
Currently, for a global variable, its debug info symbol is a named
symbol with the variable's name with a special prefix. And the
linker looks it up by name. This CL makes the debug info symbol an
aux symbol of the variable symbol.

Change-Id: I55614d0ef2af9c53eb40144ad80e09339bf3cbee
Reviewed-on: https://go-review.googlesource.com/c/go/+/490816
Run-TryBot: Cherry Mui <cherryyz@google.com>
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2023-05-02 03:09:47 +00:00
Paul E. Murphy
3c46d8f511 cmd/link: load external ELF PPC64 objects which set st_other=1
This indicates the symbol does not use or preserve the TOC pointer in
R2. Likewise, it does not have a distinct local entry point. This
happens when gcc compiles an object with -mcpu=power10.

Recycle the SymLocalentry field of a text symbol to pass through this
hint as the bogus value 1 (A valid offset must be a multiple of 4
bytes), and update the usage to check and generate errors further into
the linking process. This matches the behavior of st_other as used by
ELFv2.

Change-Id: Ic89ce17b57f400ab44213b21a3730a98c7cdf842
Reviewed-on: https://go-review.googlesource.com/c/go/+/490295
Run-TryBot: Paul Murphy <murp@ibm.com>
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Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
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2023-04-28 21:26:08 +00:00
Cherry Mui
d33a5136e1 cmd/link: use uint32 as symbol index
Currently, a symbol's global index, the Sym type, is defined as an
int, which is 64-bit on 64-bit machines. We're unlikely to have
more than 4 billion symbols in the near future. Even if we will,
we will probably hit some other limit (e.g. section size) before
the symbol number limit. Use a 32-bit type to reduce memory usage.

E,g, linking cmd/compile in external linking mode (on macOS/amd64)

Munmap_GC    43.2M ± 0%     35.5M ± 1%   -17.74%  (p=0.000 n=16+20)

This brings the memory usage back before the previous CL, and even
lower.

Change-Id: Ie185f1586638fe70d8121312bfa9410942d518c7
Reviewed-on: https://go-review.googlesource.com/c/go/+/487416
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
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2023-04-24 16:49:08 +00:00
Cherry Mui
21c2fdd91c cmd/link: use slice and bitmap for some attributes
Currently, a symbol's outer symbol, the "special" attribute, and
whether a symbol is a generator symbol are represented as maps,
and are accessed in some loops over nearly all reachable symbols.
The map lookups are a bit expensive.

For outer symbol, a non-trivial portion of the symbols have outer
symbol set (e.g. type symbols, which we put into container symbols
like "type:*"). Using a slice to access more efficiently.

For the special and generator symbol attributes, use a bitmap.
There are not many symbols have those attributes, so the bitmap is
quite sparse. The bitmap is not too large anyway, so use it for
now. If we want to further reduce memory usage we could consider
some other data structure like a Bloom filter.

Linking cmd/compile in external linking mode (on macOS/amd64)

Symtab   12.9ms ± 9%     6.4ms ± 5%   -50.08%  (p=0.000 n=19+18)
Dodata   64.9ms ±12%    57.1ms ±12%   -11.90%  (p=0.000 n=20+20)
Asmb     36.7ms ±11%    32.8ms ± 9%   -10.61%  (p=0.000 n=20+18)
Asmb2    26.6ms ±15%    21.9ms ±12%   -17.75%  (p=0.000 n=20+18)

There is some increase of memory usage

Munmap_GC   40.9M ± 1%     43.2M ± 0%    +5.54%  (p=0.000 n=20+19)

The next CL will bring the memory usage back.

Change-Id: Ie4347eb96c51f008b9284270de37fc880bb52d2c
Reviewed-on: https://go-review.googlesource.com/c/go/+/487415
Run-TryBot: Cherry Mui <cherryyz@google.com>
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Reviewed-by: Austin Clements <austin@google.com>
2023-04-24 14:00:39 +00:00
Austin Clements
2668a190ba internal/abi, runtime, cmd: merge funcFlag_* consts into internal/abi
For #59670.

Change-Id: Ie784ba4dd2701e4f455e1abde4a6bfebee4b1387
Reviewed-on: https://go-review.googlesource.com/c/go/+/485496
Reviewed-by: David Chase <drchase@google.com>
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2023-04-21 19:28:46 +00:00
Austin Clements
9754521157 internal/abi, runtime, cmd: merge funcID_* consts into internal/abi
For #59670.

Change-Id: I517e97ea74cf232e5cfbb77b127fa8804f74d84b
Reviewed-on: https://go-review.googlesource.com/c/go/+/485495
Reviewed-by: Michael Pratt <mpratt@google.com>
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2023-04-21 19:28:44 +00:00
Evan Phoenix
02411bcd7c all: implement wasmimport directive
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
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2023-03-02 05:28:55 +00:00
Than McIntosh
55bd193575 cmd/internal/obj: flag init functions in object file
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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2023-02-06 20:25:30 +00:00
cui fliter
dbfdc446fe all: fix problematic comments
Change-Id: If092ae7c72b66f172ae32fa6c7294a7ac250362e
Reviewed-on: https://go-review.googlesource.com/c/go/+/463995
Reviewed-by: Cherry Mui <cherryyz@google.com>
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2023-01-30 18:10:36 +00:00
Ian Lance Taylor
1f29f39795 cmd/link: don't export all symbols for ELF external linking
Since this may add a large number of --export-dynamic-symbol options,
use a response file if the command line gets large.

Fixes #53579

Change-Id: Ic226bf372bf1e177a3dae886d1c48f4ce3569c0e
Reviewed-on: https://go-review.googlesource.com/c/go/+/414654
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Joedian Reid <joedian@golang.org>
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2023-01-25 20:45:42 +00:00
Than McIntosh
8205d83fe2 cmd/link: improved host archive debug trace output
When ctxt.Debugvlog > 1, produce additional trace output to describe
which object files are being pulled out of host archive libraries and
why they were pulled (e.g. which symbol had a reference to something
in a library). Intended to make it easier to debug problems with cgo
internal linking.

Change-Id: Icd64aff244b9145162a00cb51642ef32f26adfba
Reviewed-on: https://go-review.googlesource.com/c/go/+/451736
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2022-11-19 22:39:30 +00:00
Michael Pratt
f2656f20ea cmd/compile,cmd/link,runtime: add start line numbers to func metadata
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
Run-TryBot: Michael Pratt <mpratt@google.com>
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2022-10-14 14:47:12 +00:00
Paul E. Murphy
edd1273b84 cmd/link: refactor usage of SymLocalentry helper functions
PPC64 ELFv2 uses the st_other field of a symbol to specify an offset
from the global entry point to its local entry point. Similarly, some
values (i.e 1) may also require additional linker support which is
missing today.

For now, generate an error if we encounter unsupported local entry
values on PPC64, and update the Localentry values to use bytes, not
32b instruction words.

Similarly, ELFv2 1.5 also updates the wording of values 2-6. They
now map to a specific number of bytes.

Change-Id: Id1b71c3b0fea982bdcfb7eac91d9f93e04ae43f9
Reviewed-on: https://go-review.googlesource.com/c/go/+/431876
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2022-09-27 17:29:05 +00:00
Jeremy Quirke
2340d37179 cmd/link: fix trampolines breaking DWARF line info
When trampolines are needed (e.g. Darwin ARM64), the DWARF LPT (Line
Program Table - see DWARF section 6.1) generation fails because the
replacement symbols are marked as external symbols and skipped during
the DWARF LPT generation phase.

Fixes #54320

Change-Id: I6c93f5378f50e5edf30d5121402a48214abb1ce2
GitHub-Last-Rev: 085bbc55dbc95d55456cc2acc46a0d02416c2848
GitHub-Pull-Request: golang/go#54321
Reviewed-on: https://go-review.googlesource.com/c/go/+/422154
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2022-08-11 14:11:53 +00:00
Cuong Manh Le
0f8dffd0aa all: use ":" for compiler generated symbols
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
Reviewed-by: Than McIntosh <thanm@google.com>
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2022-08-09 11:28:56 +00:00
Tobias Klauser
0a86cd6857 all: use io.Seek* instead of deprecated os.SEEK_*
These are available since Go 1.7. The version used for bootstrap is Go
1.17 for Go 1.20.

For #44505

Change-Id: I497c9f617baefdeb273cd115b08b6e31bd10aad2
Reviewed-on: https://go-review.googlesource.com/c/go/+/421634
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2022-08-08 17:01:54 +00:00
Cherry Mui
e3f7816f0e cmd/link: remove name expansion logic
Now both the compiler and the assembler require the -p flag and
emit full package path in symbol names, we no longer need to do
the name expansion in the linker. Delete it.

Change-Id: I771d4d97987a0a17414881b52806d600ef4cc351
Reviewed-on: https://go-review.googlesource.com/c/go/+/404300
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2022-05-12 18:45:57 +00:00
Cherry Mui
df08c9a821 cmd/link: preserve symbol attributes when cloning to external
There are some symbol attributes that are encoded in the object
file. Currently, they are lost when cloning a symbol to external.
Copy them over.

Also delete CopyAttributes as it is no longer called anywhere.

Change-Id: I1497e3223a641704bf35aa3e904dd0eda2f8ec3e
Reviewed-on: https://go-review.googlesource.com/c/go/+/400574
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2022-04-15 19:02:54 +00:00
Russ Cox
19309779ac all: gofmt main repo
[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>
2022-04-11 16:34:30 +00:00
Russ Cox
690ac4071f all: remove trailing blank doc comment lines
A future change to gofmt will rewrite

	// Doc comment.
	//
	func f()

to

	// Doc comment.
	func f()

Apply that change preemptively to all doc comments.

For #51082.

Change-Id: I4023e16cfb0729b64a8590f071cd92f17343081d
Reviewed-on: https://go-review.googlesource.com/c/go/+/384259
Trust: Russ Cox <rsc@golang.org>
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2022-04-01 18:18:07 +00:00
Russ Cox
7d87ccc860 all: fix various doc comment formatting nits
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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2022-04-01 18:18:01 +00:00
Cherry Mui
77680a0644 cmd/link: simplify content hashed symbol handling
Symbol's content hash used to depend on package path expansion in
symbol names, so we have special logic handling hashed symbols
when path expansion is needed. As we required -p in the compiler
the symbol names are now fully expanded. Remove that logic.

Change-Id: I888574f63ea3789455d96468a6abd500e0958230
Reviewed-on: https://go-review.googlesource.com/c/go/+/394218
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2022-03-22 19:39:12 +00:00
Cherry Mui
e853464055 cmd/compile, cmd/link: produce unlinkable object when compile without -p
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
Reviewed-on: https://go-review.googlesource.com/c/go/+/394217
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Reviewed-by: Matthew Dempsky <mdempsky@google.com>
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2022-03-22 19:38:35 +00:00
Cherry Mui
42d2d5e2b5 cmd/link: delete oReader.flags
Same information is provided from the fields of the embedded
goobj.Reader, and are accessed through it. Delete the flags field.

Change-Id: I7a4f5dca054e567443d719b2931fceff231d6efc
Reviewed-on: https://go-review.googlesource.com/c/go/+/394216
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2022-03-22 14:16:25 +00:00
Keith Randall
f92c8f07ac cmd/link: escape % characters in symbols when reporting errors
Generic function symbols sometimes have % in them, like:

    main.B2[%2eshape.string_0].m2·f

Which confuses this code because it doesn't esacpe % when
using this string as a format string, instead of a format argument.

Or could we get rid of the . -> %2e rewrite somehow?
I think it comes from LinkString.

Change-Id: I3275501f44cf30485e9d4577e0dfa77996d4939e
Reviewed-on: https://go-review.googlesource.com/c/go/+/357837
Trust: Keith Randall <khr@golang.org>
Trust: Dan Scales <danscales@google.com>
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Reviewed-by: Dan Scales <danscales@google.com>
2021-10-25 20:41:00 +00:00
Cherry Mui
e180e2c27c cmd/internal/goobj, cmd/link: remove funcdataoff
FUNCDATA is always a symbol reference with 0 offset. Assert the
offset is 0 and remove funcdataoff.

Change-Id: I326815365c9db5aeef6b869df5d78a9957bc16a6
Reviewed-on: https://go-review.googlesource.com/c/go/+/352894
Trust: Cherry Mui <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
2021-09-29 13:53:55 +00:00
Cherry Mui
587b3c1192 cmd/link: access pcdata via aux symbols
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
Reviewed-on: https://go-review.googlesource.com/c/go/+/352893
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2021-09-29 13:53:07 +00:00
Keith Randall
a80cbc25bd runtime: elide instantiated types in tracebacks
They tend to be things like ".shape.int" which are noisy, if not
otherwise confusing.

It would be nice to somehow print the real instantiations here, but that
requires keeping track of the dictionary argument so the instantiating
types could be found. One day, maybe, but not today.

Fixes #48578

Change-Id: I0968d24e110b6d47c9468c45372a6979575a8d29
Reviewed-on: https://go-review.googlesource.com/c/go/+/352118
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2021-09-27 19:29:58 +00:00
Cherry Mui
55d22f7490 cmd/link: remove ABI aliases
It is now gone.

Change-Id: I59f68b324af706476695de2f291dd3aa5734e192
Reviewed-on: https://go-review.googlesource.com/c/go/+/351332
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2021-09-22 15:49:52 +00:00
Cherry Mui
98989f2a74 cmd/compile, cmd/link: avoid ABI aliases
In the past we introduced ABI aliases, in preparation for ABI
wrappers. Now that we have ABI wrappers implemented, we don't
need ABI aliases. If ABI wrappers are not enabled, ABI0 and
ABIInternal are actually identical, so we can resolve symbol
references without distinguish them. This CL does so by
normalizing ABIInternal to ABI0 at link time. This way, we no
longer need to generate ABI aliases.

This CL doesn't clean up everything related to ABI aliases, which
will be done in followup CLs.

Change-Id: I5b5db43370d29b8ad153078c70a853e3263ae6f7
Reviewed-on: https://go-review.googlesource.com/c/go/+/351271
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2021-09-22 13:50:24 +00:00
Alessandro Arzilli
6268468e02 cmd/link: generate DIE for types referenced only through dictionaries
Generate debug_info entries for types that are only referenced through
dictionaries.

Change-Id: Ic36c2e6d9588ec6746793bb213c2dc0e17a8a850
Reviewed-on: https://go-review.googlesource.com/c/go/+/350532
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Trust: David Chase <drchase@google.com>
2021-09-20 18:31:54 +00:00
Tao Qingyun
4957976b1a cmd/link: make npkgsyms meaningful
npkgsyms always equals 1 currently.

Change-Id: Ie88bc273beaace12ec7432054ca7c151396e8e35
GitHub-Last-Rev: c5d3b12b88ddcdc6011f97787fd7c0e94c7df20e
GitHub-Pull-Request: golang/go#46988
Reviewed-on: https://go-review.googlesource.com/c/go/+/331929
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2021-09-03 22:56:58 +00:00
Than McIntosh
49402bee36 cmd/{compile,link}: fix bug in map.zero handling
In CL 326211 a change was made to switch "go.map.zero" symbols from
non-pkg DUPOK symbols to hashed symbols. The intent of this change was
ensure that in cases where there are multiple competing go.map.zero
symbols feeding into a link, the largest map.zero symbol is selected.
The change was buggy, however, and resulted in duplicate symbols in
the final binary (see bug cited below for details). This duplication
was relatively benign for linux/ELF, but causes duplicate definition
errors on Windows.

This patch switches "go.map.zero" symbols back from hashed symbols to
non-pkg DUPOK symbols, and updates the relevant code in the loader to
ensure that we do the right thing when there are multiple competing
DUPOK symbols with different sizes.

Fixes #47185.

Change-Id: I8aeb910c65827f5380144d07646006ba553c9251
Reviewed-on: https://go-review.googlesource.com/c/go/+/334930
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2021-07-19 13:27:46 +00:00
Than McIntosh
07ca28d529 cmd/link: fix bug in -strictdups checking of BSS symbols
The linker's -strictdups debugging option was not properly checking
for cases where you have two dupok BSS symbols with different length
(the check examined data length and content, but not symbol size).

Updates #46653.

Change-Id: I3844f25ef76dd6e4a84ffd5caed5d19a1b1a57c9
Reviewed-on: https://go-review.googlesource.com/c/go/+/326210
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2021-06-09 02:18:24 +00:00
Cherry Zhang
053fe2f485 cmd/link: emit better error for duplicated definition
Print the packages where the duplicates come from.

Change-Id: Ib3dc9aa0a3f5ddd97b03744be6d01d4bfcb33996
Reviewed-on: https://go-review.googlesource.com/c/go/+/315949
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2021-05-01 19:17:47 +00:00
Cherry Zhang
d80da19fc9 cmd/link: update comment for PLT/GOT helper functions
PLT and GOT are used more than on PE. Update the comment.

Change-Id: Iaddb326680a7709a1442675a38c021331be32472
Reviewed-on: https://go-review.googlesource.com/c/go/+/314929
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
2021-04-29 14:06:55 +00:00