Commit graph

121 commits

Author SHA1 Message Date
Austin Clements
94dba61276 internal/abi: clean up type of Kind and Type.Kind_
Currently, Type.Kind_ is a uint8, Kind is a uint, and some of the
abi.Kind consts are not of type Kind. Clean this all up by making Kind
a uint8, then making Type.Kind a Kind, and finally making all Kind
consts actually have type Kind. This has some ripple effect, but I
think all of the changes are improvements.

Change-Id: If39be74699c2cdb52bf0ad7092d392bc8fb68d15
Reviewed-on: https://go-review.googlesource.com/c/go/+/575579
Auto-Submit: Austin Clements <austin@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2024-04-02 16:25:18 +00:00
qiulaidongfeng
daaf1f2220 all: use kind* of abi
For #59670

Change-Id: Id66e102f13e529dd041b68ce869026a56f0a1b9b
GitHub-Last-Rev: 43aa9376f7
GitHub-Pull-Request: golang/go#65564
Reviewed-on: https://go-review.googlesource.com/c/go/+/562298
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Austin Clements <austin@google.com>
2024-04-02 15:10:48 +00:00
Keith Randall
e0ee5b1afa cmd/compile: move runtime.itab to internal/abi.ITab
Change-Id: I44293452764dc4bc4de8d386153c6402a9cbe409
Reviewed-on: https://go-review.googlesource.com/c/go/+/549435
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
2024-02-08 01:38:11 +00:00
Cherry Mui
fd54185a8d cmd/link, runtime: initialize packages in shared build mode
Currently, for the shared build mode, we don't generate the module
inittasks. Instead, we rely on the main executable to do the
initialization, for both the executable and the shared library.
But, with the model as of CL 478916, the main executable only
has relocations to packages that are directly imported. It won't
see the dependency edges between packages within a shared library.
Therefore indirect dependencies are not included, and thus not
initialized. E.g. main imports a, which imports b, but main
doesn't directly import b. a and b are in a shared object. When
linking main, it sees main depends on a, so it generates main's
inittasks to run a's init before main's, but it doesn't know b,
so b's init doesn't run.

This CL makes it initialize all packages in a shared library when
the library is loaded, as any of them could potentially be
imported, directly or indirectly.

Also, in the runtime, when running the init functions, make sure
to go through the DSOs in dependency order. Otherwise packages
can be initialized in the wrong order.

Fixes #61973.

Change-Id: I2a090336fe9fa0d6c7e43912f3ab233c9c47e247
Reviewed-on: https://go-review.googlesource.com/c/go/+/520375
Reviewed-by: Than McIntosh <thanm@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
2023-09-20 14:46:11 +00:00
Than McIntosh
660620dd45 cmd/link: avoid deadcode of global map vars for programs using plugins
If a program imports the plugin package, the mechanisms in place for
detecting and deleting unused global map variables are no longer safe,
since it's possibly for a given global map var to be unreferenced in
the main program but referenced by a plugin. This patch changes the
linker to test for plugin use and to avoid removing any unused global
map variables if the main program could possibly load up a plugin.

Fixes #62430.

Change-Id: Ie00b18b681cb0d259e3c859ac947ade5778cd6c8
Reviewed-on: https://go-review.googlesource.com/c/go/+/526115
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Reviewed-by: Cherry Mui <cherryyz@google.com>
2023-09-07 13:18:51 +00:00
Dominique Lefevre
b4c889b561 cmd/internal/objabi: rename R_USEGENERICIFACEMETHOD to R_USENAMEDMETHOD.
Now we have two cases when we want to keep methods with a specific name:
calls to generic interface methods and MethodByName("Foo"). Both use
the same relocation type, so let us give it a name that is not limited
to the implementation of generic interfaces.

Also, introduce staticdata.StrSymNoCommon(). It creates a symbol that
does not appear in the final binary and only communicates arguments
to the linker.

Change-Id: Icc9f49febfde1f31a4455b5acb903e8838d1c0af
Reviewed-on: https://go-review.googlesource.com/c/go/+/523016
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Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
2023-09-01 15:08:50 +00:00
Dominique Lefevre
6b52bfa393 cmd/link: remove special cases for Method() and MethodByName().
There is no more need to do this in the linker. The compiler now
handles both Type.Method() and Value.Method(), and flags their
users as ReflectMethod.

Change-Id: Ice93d5d975a1b93a324471e8abdebdce141d17d0
Reviewed-on: https://go-review.googlesource.com/c/go/+/522437
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-by: Joedian Reid <joedian@golang.org>
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2023-09-01 15:07:16 +00:00
Keith Randall
bd3f44e4ff cmd/compile: constant-fold loads from constant dictionaries and types
Retrying the original CL with a small modification. The original CL
did not handle the case of reading an itab out of a dictionary
correctly.  When we read an itab out of a dictionary, we must treat
the type inside that itab as maybe being put in an interface.

Original CL: 486895
Revert CL: 490156

Change-Id: Id2dc1699d184cd8c63dac83986a70b60b4e6cbd7
Reviewed-on: https://go-review.googlesource.com/c/go/+/491495
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
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2023-05-19 18:10:11 +00:00
Alessandro Arzilli
0bbb54a02d cmd/link: add ReflectMethod flag to -dumpdep output
Adds ReflectMethod flag to the output of -dumpdep.

Fixes #60221

Change-Id: I631d72ee21b819a3a629780317ff4d962cc121e0
Reviewed-on: https://go-review.googlesource.com/c/go/+/495715
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2023-05-19 12:07:32 +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
Keith Randall
2b92c39fe0 cmd/link: establish dependable package initialization order
(This is a retry of CL 462035 which was reverted at 474976.
The only change from that CL is the aix fix SRODATA->SNOPTRDATA
at inittask.go:141)

As described here:

https://github.com/golang/go/issues/31636#issuecomment-493271830

"Find the lexically earliest package that is not initialized yet,
but has had all its dependencies initialized, initialize that package,
 and repeat."

Simplify the runtime a bit, by just computing the ordering required
in the linker and giving a list to the runtime.

Update #31636
Fixes #57411

RELNOTE=yes

Change-Id: I28c09451d6aa677d7394c179d23c2c02c503fc56
Reviewed-on: https://go-review.googlesource.com/c/go/+/478916
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
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2023-04-14 16:55:22 +00:00
Keith Randall
642542cb3c Revert "cmd/link: establish dependable package initialization order"
This reverts commit ce2a609909.
aka CL 462035

Reason for revert: this CL is causing some problems in some internal Google programs.

Change-Id: I4476b8d8d2c3d7b5703d1d85c93baebb4b4e5d26
Reviewed-on: https://go-review.googlesource.com/c/go/+/474976
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
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Reviewed-by: Than McIntosh <thanm@google.com>
2023-03-09 19:19:41 +00:00
Keith Randall
ce2a609909 cmd/link: establish dependable package initialization order
As described here:

https://github.com/golang/go/issues/31636#issuecomment-493271830

"Find the lexically earliest package that is not initialized yet,
but has had all its dependencies initialized, initialize that package,
 and repeat."

Simplify the runtime a bit, by just computing the ordering required
in the linker and giving a list to the runtime.

Update #31636
Fixes #57411

RELNOTE=yes

Change-Id: I1e4d3878ebe6e8953527aedb730824971d722cac
Reviewed-on: https://go-review.googlesource.com/c/go/+/462035
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
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2023-03-03 23:11:37 +00:00
Than McIntosh
e2ca417ee7 cmd/link: linker portion of dead map removal
This patch contains the linker changes needed to enable deadcoding of
large unreferenced map variables, in combination with a previous
compiler change. We add a new cleanup function that runs just after
deadcode that looks for relocations in "init" funcs that are weak, of
type R_CALL (and siblings), and are targeting an unreachable function.
If we find such a relocation, after checking to make sure it targets a
map.init.XXX helper, we redirect the relocation to a point to a no-op
routine ("mapinitnoop") in the runtime.

Compilebench results for this change:

			  │ out.base.txt │            out.wrap.txt            │
			  │    sec/op    │   sec/op     vs base               │
 Template                   218.6m ±  2%   221.1m ± 1%       ~ (p=0.129 n=39)
 Unicode                    180.5m ±  1%   178.9m ± 1%  -0.93% (p=0.006 n=39)
 GoTypes                     1.162 ±  1%    1.156 ± 1%       ~ (p=0.850 n=39)
 Compiler                   143.6m ±  1%   142.6m ± 1%       ~ (p=0.743 n=39)
 SSA                         8.698 ±  1%    8.719 ± 1%       ~ (p=0.145 n=39)
 Flate                      142.6m ±  1%   143.9m ± 3%       ~ (p=0.287 n=39)
 GoParser                   247.7m ±  1%   248.8m ± 1%       ~ (p=0.265 n=39)
 Reflect                    588.0m ±  1%   590.4m ± 1%       ~ (p=0.269 n=39)
 Tar                        198.5m ±  1%   201.3m ± 1%  +1.38% (p=0.005 n=39)
 XML                        259.1m ±  1%   260.0m ± 1%       ~ (p=0.376 n=39)
 LinkCompiler               746.8m ±  2%   747.8m ± 1%       ~ (p=0.706 n=39)
 ExternalLinkCompiler        1.906 ±  0%    1.902 ± 1%       ~ (p=0.207 n=40)
 LinkWithoutDebugCompiler   522.4m ± 21%   471.1m ± 1%  -9.81% (p=0.000 n=40)
 StdCmd                      21.32 ±  0%    21.39 ± 0%  +0.32% (p=0.035 n=40)
 geomean                    609.2m         606.0m       -0.53%

			  │ out.base.txt │            out.wrap.txt            │
			  │ user-sec/op  │ user-sec/op  vs base               │
 Template                    401.9m ± 3%   406.9m ± 2%       ~ (p=0.291 n=39)
 Unicode                     191.9m ± 6%   196.1m ± 3%       ~ (p=0.052 n=39)
 GoTypes                      3.967 ± 3%    4.056 ± 1%       ~ (p=0.099 n=39)
 Compiler                    171.1m ± 3%   173.4m ± 3%       ~ (p=0.415 n=39)
 SSA                          30.04 ± 4%    30.25 ± 4%       ~ (p=0.106 n=39)
 Flate                       246.3m ± 3%   248.9m ± 4%       ~ (p=0.499 n=39)
 GoParser                    518.7m ± 1%   520.6m ± 2%       ~ (p=0.531 n=39)
 Reflect                      1.670 ± 1%    1.656 ± 2%       ~ (p=0.137 n=39)
 Tar                         352.7m ± 2%   360.3m ± 2%       ~ (p=0.117 n=39)
 XML                         528.8m ± 2%   521.1m ± 2%       ~ (p=0.296 n=39)
 LinkCompiler                 1.128 ± 2%    1.140 ± 2%       ~ (p=0.324 n=39)
 ExternalLinkCompiler         2.165 ± 2%    2.147 ± 2%       ~ (p=0.537 n=40)
 LinkWithoutDebugCompiler    484.2m ± 4%   490.7m ± 3%       ~ (p=0.897 n=40)
 geomean                     818.5m        825.1m       +0.80%

	   │ out.base.txt │             out.wrap.txt              │
	   │  text-bytes  │  text-bytes   vs base                 │
 HelloSize   766.0Ki ± 0%   766.0Ki ± 0%       ~ (p=1.000 n=40) ¹
 CmdGoSize   10.02Mi ± 0%   10.02Mi ± 0%  -0.03% (n=40)
 geomean     2.738Mi        2.738Mi       -0.01%
 ¹ all samples are equal

	   │ out.base.txt │             out.wrap.txt              │
	   │  data-bytes  │  data-bytes   vs base                 │
 HelloSize   14.17Ki ± 0%   14.17Ki ± 0%       ~ (p=1.000 n=40) ¹
 CmdGoSize   308.3Ki ± 0%   298.5Ki ± 0%  -3.19% (n=40)
 geomean     66.10Ki        65.04Ki       -1.61%
 ¹ all samples are equal

	   │ out.base.txt │             out.wrap.txt              │
	   │  bss-bytes   │  bss-bytes    vs base                 │
 HelloSize   197.3Ki ± 0%   197.3Ki ± 0%       ~ (p=1.000 n=40) ¹
 CmdGoSize   228.2Ki ± 0%   228.1Ki ± 0%  -0.01% (n=40)
 geomean     212.2Ki        212.1Ki       -0.01%
 ¹ all samples are equal

	   │ out.base.txt │            out.wrap.txt             │
	   │  exe-bytes   │  exe-bytes    vs base               │
 HelloSize   1.192Mi ± 0%   1.192Mi ± 0%  +0.00% (p=0.000 n=40)
 CmdGoSize   14.85Mi ± 0%   14.83Mi ± 0%  -0.09% (n=40)
 geomean     4.207Mi        4.205Mi       -0.05%

Also tested for any linker changes by benchmarking relink of k8s
"kubelet"; no changes to speak of there.

Updates #2559.
Updates #36021.
Updates #14840.

Change-Id: I4cc5370b3f20679a1065aaaf87bdf2881e257631
Reviewed-on: https://go-review.googlesource.com/c/go/+/463395
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
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2023-02-06 20:56:47 +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
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
Cherry Mui
91631bc7e0 cmd/link: mark unexported methods for plugins
When plugin is used, we already mark all exported methods
reachable. However, when the plugin and the host program share
a common package, an unexported method could also be reachable
from both the plugin and the host via interfaces. We need to mark
them as well.

Fixes #51621.

Change-Id: I1a70d3f96b66b803f2d0ab14d00ed0df276ea500
Reviewed-on: https://go-review.googlesource.com/c/go/+/393365
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2022-03-16 20:10:07 +00:00
Russ Cox
b37a5391f9 cmd/link, cmd/go: make version info easier to extract
Reading the version information to date has required evaluating
two pointers to strings (which themselves contain pointers to data),
which means applying relocations, which can be very system-dependent.

To simplify the lookup, inline the string data into the build info blob.

This makes go version work on binaries built with external linking
on darwin/arm64.

Also test that at least the very basics work on a trivial binary,
even in short mode.

Change-Id: I463088c19e837ae0ce57e1278c7b72e74a80b2c4
Reviewed-on: https://go-review.googlesource.com/c/go/+/369977
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2021-12-07 20:14:56 +00:00
Keith Randall
c26a32a500 cmd/compile,cmd/link: introduce generic interface call relocations
To capture the fact that a method was called on a generic interface,
so we can make sure the linker doesn't throw away any implementations
that might be the method called.

See the comment in reflect.go for details.

Fixes #49049

Change-Id: I0be74b6e727c1ecefedae072b149f59d539dc1e9
Reviewed-on: https://go-review.googlesource.com/c/go/+/357835
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Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
2021-10-25 20:39:17 +00:00
zhouguangyuan
f687831e4c cmd/link: disable weak reference in itab if build with "-linkshared"
When build with "-linkshared", we can't tell if the interface method will be used or not. It can be used in shared library.

Fixes #47873

Change-Id: Iba12812f199b7679cf2fd41a304268d6d6dd03c6
Reviewed-on: https://go-review.googlesource.com/c/go/+/350189
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2021-10-13 15:12:46 +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
Dan Scales
f5f79c47f9 [dev.typeparams] cmd/compile: use types2.Constraint() rather than types2.Bound()
types2.Constraint() returns the top-level constraint type, including any
unions or other interface elements. Because of that, we needed to
add/fix some code in the type substituter and generic type instantiater
in the importer to deal with unions and non-method members of an
interface. Also, NewUnion was not correctly setting the HasTParam flag.

I also added a better error message when a symbol is not found in
(*deadcodePass).decodeIfaceMethod().

Change-Id: Id3668dc596dce63690fa05a9e5e42295b5e2bbb5
Reviewed-on: https://go-review.googlesource.com/c/go/+/340670
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2021-08-09 20:08:06 +00:00
Cherry Mui
b4833f7c06 cmd/link: always mark runtime.unreachableMethod symbol
In the deadcode path we mark runtime.unreachableMethod symbol,
which is a special symbol used for redirecting unreachable
methods. Currently this code is conditioned on not -linkshared.
This is wrong. It should be marked with -linkshared mode as well.

In fact, -linkshared should only affect the entry symbol. Change
the code accordingly.

Change-Id: I252abf850212a930f275589ef0035a43e52cb9cc
Reviewed-on: https://go-review.googlesource.com/c/go/+/319893
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2021-05-13 21:16:06 +00:00
Russ Cox
95ed5c3800 internal/buildcfg: move build configuration out of cmd/internal/objabi
The go/build package needs access to this configuration,
so move it into a new package available to the standard library.

Change-Id: I868a94148b52350c76116451f4ad9191246adcff
Reviewed-on: https://go-review.googlesource.com/c/go/+/310731
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>
2021-04-16 19:20:53 +00:00
Austin Clements
48531da9e7 cmd/link: build dynexp symbol list directly
Currently, setCgoAttr populates the cgo_export_{static,dynamic} maps
with symbol names of exported symbols, which are then re-looked-up by
deadcode and setupdynexp, which in turn puts the re-looked-up symbols
in ctxt.dynexp. setCgoAttr already looked up the Syms, so simplify all
of this by making setCgoAttr populate ctxt.dynexp directly and
eliminating the cgo_export_{static,dynamic} maps. Recording Syms
directly also sets us up to use correct symbol versions for these
exports, rather than just assuming version 0 for all lookups.

Since setupdynexp doesn't really do any "setting up" of dynexp any
more with this change, we fold the remaining logic from setupdynexp
directly into addexport, where it has better context anyway. This also
eliminates a sorting step, since we no longer do a non-deterministic
map iteration to build the dynexp slice.

For #40724.

Change-Id: I3e1a65165268da8c2bf50d7485f2624133433260
Reviewed-on: https://go-review.googlesource.com/c/go/+/309340
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
2021-04-13 20:07:46 +00:00
Cherry Zhang
e8700f1ce6 cmd/compile, cmd/link: use weak reference in itab
When converting a type T to a non-empty interface I, we build the
itab which contains the code pointers of the methods. Currently,
this brings those methods live (if the itab is live), even if the
interface method is never used. This CL changes the itab to use
weak references, so the methods can be pruned if not otherwise
live.

Fixes #42421.

Change-Id: Iee5de2ba11d603c5a102a2ba60440d839a7f9702
Reviewed-on: https://go-review.googlesource.com/c/go/+/268479
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>
2021-03-24 14:38:53 +00:00
Austin Clements
0c93b16d01 cmd: move experiment flags into objabi.Experiment
This moves all remaining GOEXPERIMENT flags into the objabi.Experiment
struct, drops the "_enabled" from their name, and makes them all bool
typed.

We also drop DebugFlags.Fieldtrack because the previous CL shifted the
one test that used it to use GOEXPERIMENT instead.

Change-Id: I3406fe62b1c300bb4caeaffa6ca5ce56a70497fe
Reviewed-on: https://go-review.googlesource.com/c/go/+/302389
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2021-03-18 21:27:23 +00:00
Tao Qingyun
6ccb5c49cc cmd/link/internal/ld: fix typo in a comment
Change-Id: I9ae39aa2da2bfa6bb5d3f279bca764128d9cc401
GitHub-Last-Rev: 7a5945ae12
GitHub-Pull-Request: golang/go#44990
Reviewed-on: https://go-review.googlesource.com/c/go/+/301529
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Trust: Tobias Klauser <tobias.klauser@gmail.com>
2021-03-15 10:23:23 +00:00
Brad Fitzpatrick
7419a86c82 cmd/link/internal/ld: fix typo in a comment
Change-Id: I6d0fafd38f0ad9392f163a9d8cd94d103bf2a059
Reviewed-on: https://go-review.googlesource.com/c/go/+/299669
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-03-08 19:07:25 +00:00
Cherry Zhang
414fa8c35e cmd/internal/objabi: use a separate bit to mark weak relocation
Instead of using two relocation types R_XXX and R_WEAKXXX, use a
separate bit, R_WEAK, to mark weak relocations. This makes it
easier to add more weak relocation types.

Change-Id: Iec4195c2aefa65f59e464c83018246e17cd08173
Reviewed-on: https://go-review.googlesource.com/c/go/+/268478
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
2021-03-05 23:58:34 +00:00
Cherry Zhang
a655208c9e cmd/link: handle types as converted to interface when dynlink
When using plugins, a type (whose value) may be pass to a plugin
and get converted to interface there, or vice versa. We need to
treat the type as potentially converted to interface, and retain
its methods.

Should fix #44586.

Change-Id: I80dd35e68baedaa852a317543ccd78d94628d13b
Reviewed-on: https://go-review.googlesource.com/c/go/+/296709
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>
2021-02-26 16:27:08 +00:00
Russ Cox
a1222b7535 cmd/link: add debug print in deadcode
This matches the prints that deadcode prints later
as the algorithm progresses under -v=2.
It helps to see the initial conditions with -v=2 as well.

Change-Id: I06ae86fe9bd8314d003148f3d941832c9b10aef1
Reviewed-on: https://go-review.googlesource.com/c/go/+/288817
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-02-19 00:04:49 +00:00
Cherry Zhang
98f8454a73 cmd/link: don't decode type symbol in shared library in deadcode
In the linker's deadcode pass we decode type symbols for
interface satisfaction analysis. When linking against Go shared
libraries, the type symbol may come from a shared library, so it
doesn't have data in the current module being linked, so we cannot
decode it. We already have code to skip DYNIMPORT symbols. However,
this doesn't actually work, because at that point the type symbols'
names haven't been mangled, whereas they may be mangled in the
shared library. So the symbol definition (in shared library) and
reference (in current module) haven't been connected.

Skip decoding type symbols of type Sxxx (along with DYNIMPORT)
when linkShared.

Note: we cannot skip all type symbols, as we still need to mark
unexported methods defined in the current module.

Fixes #44031.

Change-Id: I833d19a060c94edbd6fc448172358f9a7d760657
Reviewed-on: https://go-review.googlesource.com/c/go/+/288496
Trust: Cherry Zhang <cherryyz@google.com>
Trust: Than McIntosh <thanm@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
2021-02-02 16:00:58 +00:00
Cherry Zhang
3a34395363 cmd/link: always mark runtime.buildVersion and runtime.modinfo reachable
runtime.buildVersion and runtime.modinfo are referenced in the
.go.buildinfo section, therefore reachable. They should normally
be reachable from the runtime. Just make it explicit, in case.

Change-Id: I60ff3132e0bbb690f4a3cba8bb18735921fbe951
Reviewed-on: https://go-review.googlesource.com/c/go/+/261637
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
2020-10-12 20:51:51 +00:00
Cherry Zhang
39dde09126 cmd/link: retain only used interface methods
Currently, in the linker's deadcode pass, when an interface type
is live, the linker thinks all its methods are live, and uses
them to match methods on concrete types. The interface method may
never be used, though.

This CL changes it to only keep used interface methods, for
matching concrete type methods. To do that, when an interface
method is used, the compiler generates a mark relocation. The
linker uses the marker relocations to mark used interface
methods, and only the used ones.

binary size    before      after
cmd/compile   18887400   18812200
cmd/go        13470652   13470492

Change-Id: I3cfd9df4a53783330ba87735853f2a0ec3c42802
Reviewed-on: https://go-review.googlesource.com/c/go/+/256798
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
2020-09-29 16:30:26 +00:00
Cherry Zhang
af18bce87c cmd/link: consider interface conversions only in reachable code
The linker prunes methods that are not directly reachable if the
receiver type is never converted to interface. Currently, this
"never" is too strong: it is invalidated even if the interface
conversion is in an unreachable function. This CL improves it by
only considering interface conversions in reachable code. To do
that, we introduce a marker relocation R_USEIFACE, which marks
the target symbol as UsedInIface if the source symbol is reached.

binary size    before      after
cmd/compile   18897528   18887400
cmd/go        13607372   13470652

Change-Id: I66c6b69eeff9ae02d84d2e6f2bc7f1b29dd53910
Reviewed-on: https://go-review.googlesource.com/c/go/+/256797
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
2020-09-28 21:30:01 +00:00
Cherry Zhang
7e54aa2c25 cmd/link: don't mark a symbol's GoType reachable when -linkshared
In CL 231397, we stopped marking symbols' GoType reachable in
general, but not when -linkshared. It was left as a TODO. This CL
addresses it.

The problem was that the type names are mangled in the shared
library, so we need to mangle the name consistently in the
executable as well (regardless of whether the symbol is reachable
or not), so that the GCProg generation code can find the
corresponding symbol from the shared library.

Change-Id: I1040747402929a983ec581109f1681a77893682e
Reviewed-on: https://go-review.googlesource.com/c/go/+/255964
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
2020-09-18 19:41:09 +00:00
Cherry Zhang
789d77a87e cmd/link: propagate UsedInIface through method descriptor
The linker prunes methods that are not directly reachable if the
receiver type is never converted to interface. A type can be
converted to interface using reflection through other types.
The linker already takes this into consideration but it missed
the case that the intermediate is a method descriptor. Handle
this case.

Change-Id: I590efc5da163c326db8d43583908a2ef67f65d9d
Reviewed-on: https://go-review.googlesource.com/c/go/+/255858
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>
2020-09-18 14:36:22 +00:00
Cherry Zhang
b22af9b407 cmd/link: record only the first occurance in Reachparent graph
In the deadcode pass, a type symbol may be marked twice, one
without UsedInIface, one with. For the second time, don't
update the Reachparent graph, so it only records the path of
the first time the symbol is reached. This ensures the
Reachparent graph is acyclic.

TODO: add a test. (This only affects GOEXPERIMENT=fieldtrack)

Change-Id: I68e8a1a69c3830bc8aee5df946151dc22dcb2b29
Reviewed-on: https://go-review.googlesource.com/c/go/+/254297
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
2020-09-11 13:53:03 +00:00
Cherry Zhang
27e3778793 [dev.link] cmd: remove "2", another round
Rename the goobj2 package to goobj.

Change-Id: Iff97b5575cbac45ac44de96b6bd9d555b9a4a12a
Reviewed-on: https://go-review.googlesource.com/c/go/+/246444
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2020-08-11 18:32:23 +00:00
Cherry Zhang
db924fd99e [dev.link] cmd/compile, cmd/link: generate itablink at link time
Currently, at compile time, for each itab symbol, we create an
"itablink" symbol which holds solely the address of the itab
symbol. At link time, all the itablink symbols are grouped
together to form the itablinks slice.

This CL removes the itablink symbols, and directly generate the
itablinks slice in the linker. This removes a number of symbols,
which are dupOK and generally have long names. And also removes
a special handling of itablink symbols in the deadcode pass which
iterates through all symbols.

Change-Id: I475c3c8899e9fbeec9abc7647b1e4a69aa5c3c5a
Reviewed-on: https://go-review.googlesource.com/c/go/+/245901
Reviewed-by: Jeremy Faller <jeremy@golang.org>
2020-08-03 21:13:25 +00:00
Cherry Zhang
4a92371291 [dev.link] cmd/link: remove "2", another round
Rename Reloc2 to Reloc, At2 to At, Aux2 to Aux.

Change-Id: Ic98d83c080e8cd80fbe1837c8f0aa134033508ce
Reviewed-on: https://go-review.googlesource.com/c/go/+/245578
Reviewed-by: Jeremy Faller <jeremy@golang.org>
2020-07-30 16:37:23 +00:00
Cherry Zhang
95848fc5c6 [dev.link] cmd/compile, cmd/link: remove dead methods if type is not used in interface
Currently, a method of a reachable type is live if it matches a
method of a reachable interface. In fact, we only need to retain
the method if the type is actually converted to an interface. If
the type is never converted to an interface, there is no way to
call the method through an interface method call (but the type
descriptor could still be used, e.g. in calling
runtime.newobject).

A type can be used in an interface in two ways:
- directly converted to interface. (Any interface counts, as it
  is possible to convert one interface to another.)
- obtained by reflection from a related type (e.g. obtaining an
  interface of T from []T).

For the former, we let the compiler emit a marker on the type
descriptor symbol when it is converted to an interface. In the
linker, we only need to check methods of marked types.

For the latter, when the linker visits a marked type, it needs to
visit all its "child" types as marked (i.e. potentially could be
converted to interface).

This reduces binary size:
cmd/compile	18792016	18706096 (-0.5%)
cmd/go		14120572	13398948 (-5.1%)

Change-Id: I4465c7eeabf575f4dc84017214c610fa05ae31fd
Reviewed-on: https://go-review.googlesource.com/c/go/+/237298
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
2020-06-11 22:32:49 +00:00
Cherry Zhang
78b96db04e [dev.link] cmd/link: reuse slice memory in deadcode pass
Reuse slice memory in the deadcode pass, reduce allocations.

Linking cmd/compile,

name           old alloc/op   new alloc/op   delta
Deadcode_GC      2.10MB ± 0%    1.41MB ± 0%  -32.61%  (p=0.008 n=5+5)

name           old allocs/op  new allocs/op  delta
Deadcode_GC       8.46k ± 0%     5.55k ± 0%  -34.45%  (p=0.008 n=5+5)

Change-Id: Ib9ba0928d68a65879007218697712b53acd3c5c5
Reviewed-on: https://go-review.googlesource.com/c/go/+/236566
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>
2020-06-04 19:14:12 +00:00
Cherry Zhang
7179e426e2 [dev.link] cmd/link: rewrite heap algorithm
Instead of using container/heap package, implement a simple
specialized heap algorithm for the work queue in the deadcode
pass, to avoid allocations and function pointer calls.

Linking cmd/compile,

name           old time/op    new time/op    delta
Deadcode_GC      59.8ms ± 4%    42.2ms ± 4%  -29.45%  (p=0.008 n=5+5)

name           old alloc/op   new alloc/op   delta
Deadcode_GC      3.53MB ± 0%    2.10MB ± 0%  -40.57%  (p=0.008 n=5+5)

name           old allocs/op  new allocs/op  delta
Deadcode_GC        187k ± 0%        8k ± 0%  -95.48%  (p=0.008 n=5+5)

Change-Id: Ibb21801d5b8e4a7eaf429856702e02720cd1772f
Reviewed-on: https://go-review.googlesource.com/c/go/+/236565
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>
2020-06-04 19:13:42 +00:00
Cherry Zhang
e4d6bfdbdf [dev.link] cmd/link: compare type descriptors for interface satisfaction analysis
Currently, in the deadcode pass, when checking whether a defined
method satisfies an interface, it compares the string
representation of the defined method and the interface method.
In fact, it can simply compare the method name and the type
descriptor (as we do in runtime). Make it so.

Change-Id: Ideb2b2410e5eedcd20ac31e3af41f5499fc90225
Reviewed-on: https://go-review.googlesource.com/c/go/+/236564
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>
2020-06-04 18:53:03 +00:00
Cherry Zhang
e0e0dab411 cmd/link: expand a TODO comment
CL 231397 is submitted too fast... Expand the comment to make it
a little clearer.

Change-Id: Ica9737aa7b51f97320bab74457388dcab8188370
Reviewed-on: https://go-review.googlesource.com/c/go/+/231597
Reviewed-by: Austin Clements <austin@google.com>
2020-05-01 20:31:11 +00:00
Cherry Zhang
44d22869a8 cmd/link: don't mark a symbol's Gotype reachable
A symbol being reachable doesn't imply its type descriptor is
needed. Don't mark it.

If the type is converted to interface somewhere in the program,
there will be an explicit use of the type descriptor, which
will make it marked.

A println("hello") program before and after

-rwxr-xr-x  1 cherryyz  primarygroup  1259824 Apr 30 23:00 hello
-rwxr-xr-x  1 cherryyz  primarygroup  1169680 Apr 30 23:10 hello

Updates #38782.
Updates #6853.

Change-Id: I88884c126ce75ba073f1ba059c4b892c87d2ac96
Reviewed-on: https://go-review.googlesource.com/c/go/+/231397
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2020-05-01 18:04:59 +00:00
Cherry Zhang
4048fb8780 [dev.link] cmd/link: combine decodesym.go and decodesym2.go
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>
2020-04-30 03:11:04 +00:00
Cherry Zhang
245a2f5780 [dev.link] cmd/link: delete ctxt.Reachparent
It is no longer needed as we have converted the fieldtrack pass
to using the loader.

Also free loader.Reachparent after we are done with it.

Change-Id: Ibc4b29f282e1e4aea363a1b549755e31f84b0295
Reviewed-on: https://go-review.googlesource.com/c/go/+/229322
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
2020-04-22 14:57:26 +00:00