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Commit Graph

4027 Commits

Author SHA1 Message Date
Josh Bleecher Snyder
faa4fa1a6e cmd/compile: allow conversion from slice to array ptr
Panic if the slice is too short.

Updates #395

Change-Id: I90f4bff2da5d8f3148ba06d2482084f32b25c29a
Reviewed-on: https://go-review.googlesource.com/c/go/+/301650
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2021-04-21 00:53:48 +00:00
Cherry Zhang
109d7580a5 cmd/compile: disable name preservation on copies in expand_calls
Apparently CL 309330 caused the compiler OOMing on some large
input (giant generated switch statement). I don't quite understand
it for now. Disable it for now.

Change-Id: I19c84f3f5e158897bff0b32d6217fcff3c66874d
Reviewed-on: https://go-review.googlesource.com/c/go/+/311829
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
2021-04-20 16:44:18 +00:00
Cherry Zhang
3ff6ff7f84 cmd/compile: preserve pointerness when creating map key temp
When creating the temporary for map functions, if the key
contains pointer, we need to create pointer-typed temporary. So
if the temporary is live across a function call, the pointer is
live.

Change-Id: Id6e14ec9def8bc7987f0f8ce8423caf1e3754fcb
Reviewed-on: https://go-review.googlesource.com/c/go/+/311379
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
2021-04-20 14:30:03 +00:00
Cherry Zhang
6b8e3e2d06 cmd/compile: reduce redundant register moves for regabi calls
Currently, if we have AX=a and BX=b, and we want to make a call
F(1, a, b), to move arguments into the desired registers it emits

	MOVQ AX, CX
	MOVL $1, AX // AX=1
	MOVQ BX, DX
	MOVQ CX, BX // BX=a
	MOVQ DX, CX // CX=b

This has a few redundant moves.

This is because we process inputs in order. First, allocate 1 to
AX, which kicks out a (in AX) to CX (a free register at the
moment). Then, allocate a to BX, which kicks out b (in BX) to DX.
Finally, put b to CX.

Notice that if we start with allocating CX=b, then BX=a, AX=1,
we will not have redundant moves. This CL reduces redundant moves
by allocating them in different order: First, for inpouts that are
already in place, keep them there. Then allocate free registers.
Then everything else.

                             before       after
cmd/compile binary size     23703888    23609680
            text size        8565899     8533291

(with regabiargs enabled.)

Change-Id: I69e1bdf745f2c90bb791f6d7c45b37384af1e874
Reviewed-on: https://go-review.googlesource.com/c/go/+/311371
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
2021-04-19 16:21:39 +00:00
Cherry Zhang
b21e739f87 test: add test for CL 310589
Change-Id: Iff0876bd17c2a93db72dc90678f3a46ef8effd74
Reviewed-on: https://go-review.googlesource.com/c/go/+/311370
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2021-04-19 14:51:24 +00:00
Cherry Zhang
a9c244a849 test: add liveness test for regabi
With defer/go wrapping and register arguments, some liveness info
changed and live.go test was disabled for regabi. This CL adds a
new one for regabi.

Change-Id: I65f03a6ef156366d8b76c62a16251c3e818f4b02
Reviewed-on: https://go-review.googlesource.com/c/go/+/311369
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
2021-04-19 14:42:58 +00:00
Cuong Manh Le
a72622d028 cmd/compile: skip "_" function in reflectdata.MarkUsedIfaceMethod
CL 256798 added compiler ability to retain only used interface methods,
by generating a mark relocation whenever an interface method is used. To
do that, the compiler needs the current function linker object.

However, for unnamed function "func _()", its linker object is nil,
causes the compiler crashes for code in #45258.

CL 283313 fixed the code in #45258 unintentionally, since when the
compiler now does not walk unnamed functions anymore.

This CL fixes the root issue, by making reflectdata.MarkUsedIfaceMethod
skips unnamed functions, and also adding regression test.

Fixes #45258

Change-Id: I4cbefb0a89d9928f70c00dc8a271cb61cd20a49c
Reviewed-on: https://go-review.googlesource.com/c/go/+/311130
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2021-04-19 04:37:32 +00:00
Russ Cox
dba89283ad cmd/go, go/build: add ToolTags to build.Default
The build.Default context really needs to accurately describe
the default build context. The goexperiment tags being a special
case in the go command violates that rule and is the root cause
of the various try-bot failures blocking the enabling of regabi.

(The cleanups I made in golang.org/x/tools were long overdue
but are not strictly necessary for making regabi work; this CL is.)

Having moved the GOEXPERIMENT parsing into internal/buildcfg,
go/build can now use it to set up build.Default, in the new field
ToolTags, meant to hold toolchain-determined tags (for now,
just the experiments). And at the same time we can remove the
duplication of GOOS and GOARCH defaults.

And then once build.Default is set up accurately, the special case
code in cmd/go itself can be removed, and the special case code
in test/run.go is at least a bit less special.

Change-Id: Ib7394e10aa018e492cb9a83fb8fb9a5011a8c25b
Reviewed-on: https://go-review.googlesource.com/c/go/+/310732
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
Reviewed-by: Austin Clements <austin@google.com>
2021-04-16 19:21:48 +00:00
David Chase
52df9291aa test/abi: reenable test on windows
Reverses CL 308889.
Fixes #45465.
Updates #40724.

Change-Id: I34b0d396dc34d0ec8c216e9b6a668de9dfce677c
Reviewed-on: https://go-review.googlesource.com/c/go/+/310649
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
2021-04-16 13:38:02 +00:00
Austin Clements
d26fc68aa1 cmd/internal/objabi,test: use correct GOEXPERIMENT build tags in test/run.go
Currently, run.go sets GOEXPERIMENT build tags based on the
*difference* from the baseline experiment configuration, rather than
the absolute experiment configuration. This differs from cmd/go. As a
result, if we set a baseline configuration and don't override it with
a GOEXPERIMENT setting, run.go won't set any GOEXPERIMENT build tags,
instead of setting the tags corresponding to the baseline
configuration.

Fix this by making compile -V=goexperiment produce the full
GOEXPERIMENT configuration, which run.go can then use to set exactly
the right set of build tags.

For #40724.

Change-Id: Ieda6ea62f1a1fabbe8d749d6d09c198fd5ca8377
Reviewed-on: https://go-review.googlesource.com/c/go/+/310171
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>
2021-04-16 03:16:55 +00:00
Robert Griesemer
a63ff398d5 cmd/compile/internal/syntax: fix error message for ... without type
Only complain about missing type; leave it to type-checking
to decide whether "..." is permitted in the first place.

Fixes #43674.

Change-Id: Icbc8f084e364fe3ac16076406a134354219c08d0
Reviewed-on: https://go-review.googlesource.com/c/go/+/310209
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
2021-04-15 19:41:38 +00:00
Keith Randall
083a26c7d2 cmd/compile: propagate pragmas from generic function to stenciled implementation
Change-Id: I28a1910890659aaa449ffd2a847cd4ced5a8600d
Reviewed-on: https://go-review.googlesource.com/c/go/+/310211
Trust: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
2021-04-15 00:29:05 +00:00
Dan Scales
bf634c76b2 cmd/compile: look for function in instantiations in all global assignments
Add in some missing global assignment ops to the list of globals ops
that should be traversed to look for generic function instantiations.
The most common other one for global assigments (and the relevant one
for this bug) is OAS2FUNC, but also look at global assigments with
OAS2DOTTYPE, OAS2MAPR, OAS2RECV, and OASOP.

Bonus small fix: get rid of -G=3 case in ir.IsAddressable. Now that we
don't call the old typechecker from noder2, we don't need this -G-3
check anymore.

Fixes #45547.

Change-Id: I75fecec55ea0d6f62e1c2294d4d77447ed9be6ae
Reviewed-on: https://go-review.googlesource.com/c/go/+/310210
Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2021-04-15 00:14:55 +00:00
David Chase
4df3d0e4df cmd/compile: rescue stmt boundaries from OpArgXXXReg and OpSelectN.
Fixes this failure:
go test cmd/compile/internal/ssa -run TestStmtLines -v
=== RUN   TestStmtLines
    stmtlines_test.go:115: Saw too many (amd64, > 1%) lines without
    statement marks, total=88263, nostmt=1930
    ('-run TestStmtLines -v' lists failing lines)

The failure has two causes.

One is that the first-line adjuster in code generation was relocating
"first lines" to instructions that would either not have any code generated,
or would have the statment marker removed by a different believed-good heuristic.

The other was that statement boundaries were getting attached to register
values (that with the old ABI were loads from the stack, hence real instructions).
The register values disappear at code generation.

The fixes are to (1) note that certain instructions are not good choices for
"first value" and skip them, and (2) in an expandCalls post-pass, look for
register valued instructions and under appropriate conditions move their
statement marker to a compatible use.

Also updates TestStmtLines to always log the score, for easier comparison of
minor compiler changes.

Updates #40724.

Change-Id: I485573ce900e292d7c44574adb7629cdb4695c3f
Reviewed-on: https://go-review.googlesource.com/c/go/+/309649
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-04-14 18:46:08 +00:00
Keith Randall
6d8ba77896 cmd/compile: fix importing of method expressions
For OMETHEXPR, the Name in the Selection needs to be properly
linked up to the method declaration. Use the same code we
already have for ODOTMETH and OCALLPART to do that.

Fixes #45503

Change-Id: I7d6f886d606bae6faad8c104f50c177f871d41c8
Reviewed-on: https://go-review.googlesource.com/c/go/+/309831
Trust: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Dan Scales <danscales@google.com>
2021-04-14 04:02:01 +00:00
Dan Scales
eb433ed5a2 cmd/compile: set types properly for imported funcs with closures
For the new export/import of node types, we were just missing setting
the types of the closure variables (which have the same types as the
captured variables) and the OCLOSURE node itself (which has the same
type as the Func node).

Re-enabled inlining of functions with closures.

Change-Id: I687149b061f3ffeec3244ff02dc6e946659077a9
Reviewed-on: https://go-review.googlesource.com/c/go/+/308974
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2021-04-14 01:28:16 +00:00
Cherry Zhang
444d28295b test: make codegen/memops.go work with both ABIs
Following CL 309335, this fixes memops.go.

Change-Id: Ia2458b5267deee9f906f76c50e70a021ea2fcb5b
Reviewed-on: https://go-review.googlesource.com/c/go/+/309552
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
2021-04-13 14:07:17 +00:00
Cherry Zhang
263e13d1f7 test: make codegen tests work with both ABIs
Some codegen tests were written with the assumption that
arguments and results are in memory, and with a specific stack
layout. With the register ABI, the assumption is no longer true.
Adjust the tests to work with both cases.

- For tests expecting in memory arguments/results, change to use
  global variables or memory-assigned argument/results.

- Allow more registers. E.g. some tests expecting register names
  contain only letters (e.g. AX), but  it can also contain numbers
  (e.g. R10).

- Some instruction selection changes when operate on register vs.
  memory, e.g. ADDQ vs. LEAQ, MOVB vs. MOVL. Accept both.

TODO: mathbits.go and memops.go still need fix.
Change-Id: Ic5932b4b5dd3f5d30ed078d296476b641420c4c5
Reviewed-on: https://go-review.googlesource.com/c/go/+/309335
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2021-04-12 21:59:59 +00:00
Cherry Zhang
9ed0e32059 test: consider default GOEXPERIMENT when matching build tags
If GOEXPERIMENT environment variable is unset, use the default
value that is baked into the toolchain (instead of no
experiments).

Change-Id: I41f863e6f7439f2d53e3ebd25a7d9cf4a176e32e
Reviewed-on: https://go-review.googlesource.com/c/go/+/309333
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>
2021-04-12 16:25:59 +00:00
Keith Randall
1129a60f1c cmd/compile: include typecheck information in export/import
Include type information on exported function bodies, so that the
importer does not have to re-typecheck the body. This involves
including type information in the encoded output, as well as
avoiding some of the opcode rewriting and other changes that the
old exporter did assuming there would be a re-typechecking pass.

This CL could be considered a cleanup, but is more important than that
because it is an enabling change for generics. Without this CL, we'd
have to upgrade the current typechecker to understand generics. With
this CL, the current typechecker can mostly go away in favor of the
types2 typechecker.

For now, inlining of functions that contain closures is turned off.
We will hopefully resolve this before freeze.

Object files are only 0.07% bigger.

Change-Id: I85c9da09f66bfdc910dc3e26abb2613a1831634d
Reviewed-on: https://go-review.googlesource.com/c/go/+/301291
Trust: Keith Randall <khr@golang.org>
Trust: Dan Scales <danscales@google.com>
Reviewed-by: Dan Scales <danscales@google.com>
2021-04-10 14:58:18 +00:00
Cherry Zhang
5305bdedb0 test: do not run (another) softfloat test with regabiargs
I missed one in CL 308710.

Change-Id: Ia277eaba6982f4944992d1bee1e11775934b789f
Reviewed-on: https://go-review.googlesource.com/c/go/+/309151
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
2021-04-09 23:18:47 +00:00
David Chase
d11968012c test/abi: disable test with old-style build tag known to run.go
A quick check of the source to run.go suggests that it does not
look for the new-style build tags.

Updates #45465.

Change-Id: Ib4be040935d71e732f81d52c4a22c2b514195f40
Reviewed-on: https://go-review.googlesource.com/c/go/+/308934
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Trust: David Chase <drchase@google.com>
2021-04-09 17:37:22 +00:00
David Chase
d138ee2cfb test/abi: disable test on windows for now
This tickles some other bug, do this to clear builders.

Updates #40724.
Updates #45465.

Change-Id: Id51efbcf474865da231fcbc6216e5d604f99c296
Reviewed-on: https://go-review.googlesource.com/c/go/+/308889
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
2021-04-09 14:31:01 +00:00
Cherry Zhang
d25c4fbe05 test: do not run softfloat test with regabiargs
Softfloat mode with register ABI is not implemented yet. In
particular, we did not rewrite the float types in AuxCalls to
integer types, so arguments are still passed in floating point
registers, which do not exist in softfloat mode. To make it work
I think we may want to reorder softfloat pass with expand_calls
pass. We also need to rewrite the OpArgFloatRegs for the spilling
of non-SSA-able arguments, which may involve renumbering interger
arguments. Maybe in softfloat mode we want to just define the
ABI with 0 float registers. They are not fundamentally hard, but
may be not worth doing for the moment, as we don't use softfloat
mode on AMD64 anyway.

Run the test with noregabiargs. Also in the compiler reject
-d=softfloat if regabiargs is enabled.

Change-Id: I8cc0c2cfa88a138bc1338ed8710670245f1bd2cd
Reviewed-on: https://go-review.googlesource.com/c/go/+/308710
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
2021-04-09 00:11:25 +00:00
Than McIntosh
bb76193a7f cmd/compile: fix buglet in walk convert phase relating to convF32/64
The helper function used by the compiler's walk phase to determine
whether a param can be passed in a single float register wasn't quite
correct (didn't allow for the possibility of struct with two fields,
first zero size and second float). Fix up the helper to take this
case into account.

Updates #40724.

Change-Id: I55b42a1b17ea86de1d696788f029ad3aae4a179c
Reviewed-on: https://go-review.googlesource.com/c/go/+/308689
Trust: Than McIntosh <thanm@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-04-08 19:58:50 +00:00
Than McIntosh
ca8540affd cmd/compile: fix buglet in walk convert phase relating to convT64
The function runtime.convT64 accepts a single uint64 argument, but the
compiler's rules in the walk phase for determining whether is it ok to
pass a value of type T to a call to runtime.convT64 were slightly off.
In particular the test was allowing a type T with size less than eight
bytes but with more than one internal element (e.g. a struct). This
patch tightens up the rules somewhat to prevent this from happening.

Updates #40724.

Change-Id: I3b909267534db59429b0aa73a3d73333e1bd6432
Reviewed-on: https://go-review.googlesource.com/c/go/+/308069
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>
2021-04-08 17:44:21 +00:00
David Chase
d474b6c824 test/abi: clean up test to fix builders
go.mod file was not tidy, made builders sad.

Updates #40724.

Change-Id: I28371a1093108f9ec473eb20bb4d185e35dee67d
Reviewed-on: https://go-review.googlesource.com/c/go/+/308590
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-04-08 17:43:33 +00:00
David Chase
283b02063b cmd/compile: sanitize before/after expansion OpSelectN references
In expand_calls, OpSelectN occurs both before and after the rewriting.
Attempting to rewrite a post-expansion OpSelectN is bad.
(The only ones rewritten in place are the ones returning mem;
others are synthesized to replace other selection chains with
register references.)

Updates #40724.
Updates #44816#issuecomment-815258897.

Change-Id: I7b6022cfb47f808d3ce6cc796c067245f36047f3
Reviewed-on: https://go-review.googlesource.com/c/go/+/308309
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
2021-04-08 15:03:31 +00:00
Robert Griesemer
4bbe046aad cmd/compile/internal/syntax: add "~" operator
Change-Id: I7991103d97b97260d9615b7f5baf7ec75ad87d1f
Reviewed-on: https://go-review.googlesource.com/c/go/+/307370
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
2021-04-07 05:19:41 +00:00
David Chase
8462169b5a cmd/compile: pre-spill pointers in aggregate-typed register args
There's a problem in liveness, where liveness of any
part of an aggregate keeps the whole aggregate alive,
but the not-live parts don't get spilled.  The GC
can observe those live-but-not-spilled slots, which
can contain junk.

A better fix is to change liveness to work
pointer-by-pointer, but that is also a riskier,
trickier fix.

To avoid this, in the case of

(1) an aggregate input parameter
(2) containing pointers
(3) passed in registers

pre-spill the pointers.

Updates #40724.

Change-Id: I6beb8e0a353b1ae3c68c16072f56698061922c04
Reviewed-on: https://go-review.googlesource.com/c/go/+/307909
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-04-07 03:42:11 +00:00
eric fang
8d77e45064 cmd/compile: fix bug of conditional instructions on arm64
CL 302231 added some optimization rules with instructions CSETM, CSINC,
CSINV, and CSNEG, but did not deal with the situation where flag is
constant, resulting in some cases that could be more optimized cannot
be optimized, and the FlagConstant value is passed to codegen pass. This
CL adds these missing rules.

Fixes #45359

Change-Id: I700608cfb9a6a768a18d1fd5d374d7e92aa6f838
Reviewed-on: https://go-review.googlesource.com/c/go/+/307650
Reviewed-by: eric fang <eric.fang@arm.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>
Run-TryBot: eric fang <eric.fang@arm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: eric fang <eric.fang@arm.com>
Trust: Alberto Donizetti <alb.donizetti@gmail.com>
2021-04-07 02:05:55 +00:00
Cherry Zhang
f5efa5a313 cmd/compile: load results into registers on open defer return path
When a function panics then recovers, it needs to return to the
caller with named results having the correct values. For
in-register results, we need to load them into registers at the
defer return path.

For non-open-coded defers, we already generate correct code, as
the defer return path is part of the SSA CFG and contains the
instructions that are the same as an ordinary return statement,
including putting the results to the right places.

For open-coded defers, we have a special code generation that
emits a disconnected block that currently contains only the
deferreturn call and a RET instruction. It leaves the result
registers unset. This CL adds instructions that load the result
registers on that path.

Updates #40724.

Change-Id: I1f60514da644fd5fb4b4871a1153c62f42927282
Reviewed-on: https://go-review.googlesource.com/c/go/+/307231
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Austin Clements <austin@google.com>
2021-04-06 20:22:15 +00:00
Robert Griesemer
d57189e92b test/syntax: remove interface.go
The exact same test case covered by this file is also in
fixedbugs/bug121.go. No need for duplication.

Also, the actual syntax error tested (multiple method names
with a single signature) is an unlikely syntax error, and
only here for historical reasons (in the very beginning, this
was actually possible to write). Now, virtually nobody is making
this mistake.

Change-Id: I9d68e0aee2a63025f44e6338647f8250ecc3077a
Reviewed-on: https://go-review.googlesource.com/c/go/+/307789
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2021-04-06 18:55:39 +00:00
David Chase
ee40bb666b cmd/compile: add "surprised by IData of Arg" case for register args
This fixes a compile crash for
GOEXPERIMENT=regabi,regabiargs go test -c  go/constant

Updates #40724.

Change-Id: I238cef436e045647815326fc8fdb025c30ba1f5c
Reviewed-on: https://go-review.googlesource.com/c/go/+/307309
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-04-05 20:11:08 +00:00
KimMachineGun
a040ebeb98 all: update references to symbols moved from io/ioutil to io
Update references missed in CL 263142.

For #41190

Change-Id: I778760a6a69bd0440fec0848bdef539c9ccb4ee1
GitHub-Last-Rev: dda42b09ff
GitHub-Pull-Request: golang/go#42874
Reviewed-on: https://go-review.googlesource.com/c/go/+/273946
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Cherry Zhang <cherryyz@google.com>
2021-04-05 17:51:15 +00:00
David Chase
254948a50e cmd/compile: mark unused values as invalid to prevent problems in expandCalls
Leftover values that have been replaced can cause problems in later
passes (within expandCalls).  For example, a struct select that
itself yields a struct will have a problematic rewrite, if the chance
is presented.

Updates #40724.

Change-Id: I1b445c47c301c3705f7fc0a9d39f1f5c84f4e190
Reviewed-on: https://go-review.googlesource.com/c/go/+/306869
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
2021-04-02 17:58:59 +00:00
Keith Randall
aebc0b473e cmd/compile: fix bug in phiopt pass
The math to invert the input index was wrong.

Fixes #45323

Change-Id: I7c68cac280e8f01a9c806ecb0f195f169267437e
Reviewed-on: https://go-review.googlesource.com/c/go/+/306431
Trust: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: fannie zhang <Fannie.Zhang@arm.com>
Reviewed-by: David Chase <drchase@google.com>
2021-04-02 05:24:14 +00:00
Cherry Zhang
5579ee169f cmd/compile: in expand calls, preserve pointer store type but decompose aggregate args
In CL 305672 we preserve the pointer type of a store by just not
decomposing it. But this can be problematic when the source of
the store is a direct interface aggregate type (e.g.
struct { x map[int]int }.

In this CL we take a different approach: we preserve the store
type when generating the new store, but also decompose the source.

Fixes #45344.

Change-Id: If5dd496458dee95aa649c6d106b96a6cdcf3e60d
Reviewed-on: https://go-review.googlesource.com/c/go/+/306669
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2021-04-02 00:45:56 +00:00
David Chase
45ca9ef5c1 cmd/compile: fix register/offset calculation for trailing empty field case.
Includes test.
Long term, need to make the offending code be more in terms
of official types package offsets, instead of duplicating that
logic.

For #40724.

Change-Id: Id33a153f10aed3289cc48d1f99a8e0f6ece9474d
Reviewed-on: https://go-review.googlesource.com/c/go/+/306469
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-04-01 15:50:43 +00:00
Cherry Zhang
5d6581d747 cmd/compile: deduplicate OpArg's across types
For in-register arguments, it must have only a single copy of it
present in the function. If there are multiple copies, it confuses
the register allocator, as they are in the same register.

Change-Id: I55cb06746f08aa7c9168026d0f411bce0a9f93f4
Reviewed-on: https://go-review.googlesource.com/c/go/+/306330
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2021-03-31 20:21:57 +00:00
Dan Scales
f2717b31b5 cmd/compile: deal correctly with unnamed function params during stenciling
During substitution of the function type during stenciling, we must set
the Name nodes of the param/result fields of the func type. We get those
name nodes from the substituted Dcl nodes of the PPARAMS and PPARAMOUTs.
But we must check that the names match with the Dcl nodes, so that we
skip any param fields that correspond to unnamed (in) parameters.

Added a few tests to typelist.go by removing a variety of unneeded
function parameter names.

Change-Id: If786961b64549da6f18eeeb5060ea58fab874eb9
Reviewed-on: https://go-review.googlesource.com/c/go/+/305912
Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2021-03-31 00:52:26 +00:00
Cherry Zhang
64ca7e2cb3 cmd/compile: avoid generating duplicated in-register Arg
In expand_calls, when rewriting OpArg to OpArgIntReg/OpArgFloatReg,
avoid generating duplicates. Otherwise it will confuse the
register allocator: it would think the second occurance clobbers
the first's register, causing it to generate copies, which may
clobber other args.

Change-Id: I4f1dc0519afb77500eae1c0e6ac8745e51f7aa4e
Reviewed-on: https://go-review.googlesource.com/c/go/+/306029
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: David Chase <drchase@google.com>
2021-03-30 22:10:19 +00:00
Dan Scales
1318fb4a32 cmd/compile: handle partial type inference that doesn't require function args
Handle the case where types can be partially inferred for an
instantiated function that is not immediately called. The key for the
Inferred map is the CallExpr (if inferring types required the function
arguments) or the IndexExpr (if types could be inferred without the
function arguments).

Added new tests for the case where the function isn't immediately called
to typelist.go.

Change-Id: I60f503ad67cd192da2f2002060229efd4930dc39
Reviewed-on: https://go-review.googlesource.com/c/go/+/305909
Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
2021-03-30 19:44:38 +00:00
Dan Scales
032ef4bbfc cmd/compile: fix creation of named generic types (setting of t.nod)
The correct setting of t.nod is needed when exporting types. Make sure
we create instantiated named types correctly so t.nod is set.

New test file interfacearg.go that tests this (by instantiating a type
with an interface). Also has tests for various kinds of method
expressions.

Change-Id: Ia7fd9debd495336b73788af9e35d72331bb7d2b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/305730
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2021-03-30 04:48:27 +00:00
Dan Scales
eeadfa2d38 cmd/compile: fix various small bugs related to type lists
Fix various small bugs related to delaying transformations due to type
params. Most of these relate to the need to delay a transformation when
an argument of an expression or statement has a type parameter that has
a structural constraint. The structural constraint implies the operation
should work, but the transformation can't happen until the actual value
of the type parameter is known.

 - delay transformations for send statements and return statements if
   any args/values have type params.

 - similarly, delay transformation of a call where the function arg has
   type parameters. This is mainly important for the case where the
   function arg is a pure type parameter, but has a structural
   constraint that requires it to be a function. Move the setting of
   n.Use to transformCall(), since we may not know how many return
   values there are until then, if the function arg is a type parameter.

 - set the type of unary expressions from the type2 type (as we do with
   most other expressions), since that works better with expressions
   with type params.

 - deal with these delayed transformations in subster.node() and convert
   the CALL checks to a switch statement.

 - make sure ir.CurFunc is set properly during stenciling, including
   closures (needed for transforming return statements during
   stenciling).

New test file typelist.go with tests for these cases.

Change-Id: I1b82f949d8cec47d906429209e846f4ebc8ec85e
Reviewed-on: https://go-review.googlesource.com/c/go/+/305729
Trust: Dan Scales <danscales@google.com>
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2021-03-30 03:05:45 +00:00
fanzha02
ba6bd967d2 cmd/compile/internal/ssa: strengthen phiopt pass
The current phiopt pass just transforms the following code
  x := false
  if b { x = true}
into
  x = b

But we find code in runtime.atoi like this:
  neg := false
  if s[0] == '-' {
    neg = true
    s = s[1:]
  }

The current phiopt pass does not covert it into code like:
  neg := s[0] == '-'
  if neg { s = s[1:] }

Therefore, this patch strengthens the phiopt pass so that the
boolean Phi value "neg" can be replaced with a copy of control
value "s[0] == '-'", thereby using "cmp+cset" instead of a branch.

But in some cases even replacing the boolean Phis cannot eliminate
this branch. In the following case, this patch replaces "d" with a
copy of "a<0", but the regalloc pass will insert the "Load {c}"
value into an empty block to split the live ranges, which causes
the branch to not be eliminated.

For example:
  func test(a, b, c int) (bool, int) {
    d := false
    if (a<0) {
      if (b<0) {
        c = c+1
      }
      d = true
    }
    return d, c
  }

The optimized assembly code:
  MOVD "".a(FP), R0
  TBZ $63, R0, 48
  MOVD "".c+16(FP), R1
  ADD $1, R1, R2
  MOVD "".b+8(FP), R3
  CMP ZR, R3
  CSEL LT, R2, R1, R1
  CMP ZR, R0
  CSET LT, R0
  MOVB R0, "".~r3+24(FP)
  MOVD R1, "".~r4+32(FP)
  RET (R30)
  MOVD "".c+16(FP), R1
  JMP 28

The benchmark:

name          old time/op            new time/op            delta
pkg:cmd/compile/internal/ssa goos:linux goarch:arm64
PhioptPass  117783.250000ns +- 1%  117219.111111ns +- 1%   ~  (p=0.074  n=8+9)

Statistical data from compilecmp tool:

compilecmp local/master -> HEAD
local/master (a826f7dc45): debug/dwarf: support DW_FORM_rnglistx aka formRnglistx
HEAD (e57e003c10): cmd/compile/internal/ssa: strengthen phiopt pass

benchstat -geomean  /tmp/2516644532 /tmp/1075915815
completed 50 of 50, estimated time remaining 0s (ETA 7:10PM)
name                      old time/op       new time/op       delta
Template                        554ms _ 3%        553ms _ 3%    ~     (p=0.986 n=49+48)
Unicode                         252ms _ 4%        249ms _ 4%  -1.33%  (p=0.002 n=47+49)
GoTypes                         3.16s _ 3%        3.18s _ 3%  +0.77%  (p=0.022 n=44+48)
Compiler                        257ms _ 4%        258ms _ 4%    ~     (p=0.121 n=50+49)
SSA                             24.2s _ 4%        24.2s _ 5%    ~     (p=0.694 n=49+50)
Flate                           338ms _ 4%        338ms _ 4%    ~     (p=0.592 n=43+46)
GoParser                        506ms _ 3%        507ms _ 3%    ~     (p=0.942 n=49+50)
Reflect                         1.37s _ 4%        1.37s _ 5%    ~     (p=0.408 n=50+50)
Tar                             486ms _ 3%        487ms _ 4%    ~     (p=0.911 n=47+50)
XML                             619ms _ 2%        619ms _ 3%    ~     (p=0.368 n=46+48)
LinkCompiler                    1.29s _31%        1.32s _23%    ~     (p=0.306 n=49+44)
ExternalLinkCompiler            3.39s _10%        3.36s _ 6%    ~     (p=0.311 n=48+46)
LinkWithoutDebugCompiler        846ms _37%        793ms _24%  -6.29%  (p=0.040 n=50+49)
[Geo mean]                      974ms             971ms       -0.36%

name                      old user-time/op  new user-time/op  delta
Template                        910ms _12%        893ms _13%    ~     (p=0.098 n=49+49)
Unicode                         495ms _28%        492ms _18%    ~     (p=0.562 n=50+46)
GoTypes                         4.42s _15%        4.39s _13%    ~     (p=0.684 n=49+50)
Compiler                        419ms _22%        422ms _16%    ~     (p=0.579 n=48+50)
SSA                             36.5s _ 7%        36.6s _ 8%    ~     (p=0.465 n=50+47)
Flate                           521ms _21%        523ms _16%    ~     (p=0.889 n=50+47)
GoParser                        810ms _12%        792ms _15%    ~     (p=0.149 n=50+50)
Reflect                         1.98s _13%        2.02s _13%    ~     (p=0.144 n=47+50)
Tar                             826ms _15%        806ms _19%    ~     (p=0.115 n=49+49)
XML                             988ms _14%       1003ms _14%    ~     (p=0.179 n=50+50)
LinkCompiler                    1.79s _ 8%        1.84s _11%  +2.81%  (p=0.001 n=49+49)
ExternalLinkCompiler            3.69s _ 4%        3.71s _ 3%    ~     (p=0.261 n=50+50)
LinkWithoutDebugCompiler        838ms _10%        827ms _11%    ~     (p=0.323 n=50+48)
[Geo mean]                      1.44s             1.44s       -0.05%

name                      old alloc/op      new alloc/op      delta
Template                       39.0MB _ 1%       39.0MB _ 1%    ~     (p=0.445 n=50+49)
Unicode                        28.5MB _ 0%       28.5MB _ 0%    ~     (p=0.460 n=50+50)
GoTypes                         169MB _ 1%        169MB _ 1%    ~     (p=0.092 n=48+50)
Compiler                       23.4MB _ 1%       23.4MB _ 1%  -0.19%  (p=0.032 n=50+49)
SSA                            1.54GB _ 0%       1.55GB _ 1%  +0.14%  (p=0.001 n=50+50)
Flate                          23.8MB _ 1%       23.8MB _ 2%    ~     (p=0.702 n=49+49)
GoParser                       35.4MB _ 1%       35.4MB _ 1%    ~     (p=0.786 n=50+50)
Reflect                        85.3MB _ 1%       85.3MB _ 1%    ~     (p=0.298 n=50+50)
Tar                            34.6MB _ 2%       34.6MB _ 2%    ~     (p=0.683 n=50+50)
XML                            44.5MB _ 3%       44.0MB _ 2%  -1.05%  (p=0.000 n=50+46)
LinkCompiler                    136MB _ 0%        136MB _ 0%  +0.01%  (p=0.005 n=50+50)
ExternalLinkCompiler            128MB _ 0%        128MB _ 0%    ~     (p=0.179 n=50+50)
LinkWithoutDebugCompiler       84.3MB _ 0%       84.3MB _ 0%  +0.01%  (p=0.006 n=50+50)
[Geo mean]                     70.7MB            70.6MB       -0.07%

name                      old allocs/op     new allocs/op     delta
Template                         410k _ 0%         410k _ 0%    ~     (p=0.606 n=48+49)
Unicode                          310k _ 0%         310k _ 0%    ~     (p=0.674 n=50+50)
GoTypes                         1.81M _ 0%        1.81M _ 0%    ~     (p=0.674 n=50+50)
Compiler                         202k _ 0%         202k _ 0%  +0.02%  (p=0.046 n=50+50)
SSA                             16.3M _ 0%        16.3M _ 0%  +0.10%  (p=0.000 n=50+50)
Flate                            244k _ 0%         244k _ 0%    ~     (p=0.834 n=49+50)
GoParser                         380k _ 0%         380k _ 0%    ~     (p=0.410 n=50+50)
Reflect                         1.08M _ 0%        1.08M _ 0%    ~     (p=0.782 n=48+50)
Tar                              368k _ 0%         368k _ 0%    ~     (p=0.585 n=50+49)
XML                              453k _ 0%         453k _ 0%  -0.01%  (p=0.025 n=49+49)
LinkCompiler                     713k _ 0%         713k _ 0%  +0.01%  (p=0.044 n=50+50)
ExternalLinkCompiler             794k _ 0%         794k _ 0%  +0.01%  (p=0.000 n=50+49)
LinkWithoutDebugCompiler         251k _ 0%         251k _ 0%    ~     (p=0.092 n=47+50)
[Geo mean]                       615k              615k       +0.01%

name                      old maxRSS/op     new maxRSS/op     delta
Template                        37.0M _ 4%        37.2M _ 3%    ~     (p=0.062 n=48+48)
Unicode                         36.9M _ 5%        37.3M _ 4%  +1.10%  (p=0.021 n=50+47)
GoTypes                         94.3M _ 3%        94.9M _ 4%  +0.69%  (p=0.022 n=45+46)
Compiler                        33.4M _ 3%        33.4M _ 5%    ~     (p=0.964 n=49+50)
SSA                              741M _ 3%         738M _ 3%    ~     (p=0.164 n=50+50)
Flate                           28.5M _ 6%        28.8M _ 4%  +1.07%  (p=0.009 n=50+49)
GoParser                        35.0M _ 3%        35.3M _ 4%  +0.83%  (p=0.010 n=50+48)
Reflect                         57.2M _ 6%        57.1M _ 4%    ~     (p=0.815 n=50+49)
Tar                             34.9M _ 3%        35.0M _ 3%    ~     (p=0.134 n=49+48)
XML                             39.5M _ 5%        40.0M _ 3%  +1.35%  (p=0.001 n=50+48)
LinkCompiler                     220M _ 2%         220M _ 2%    ~     (p=0.547 n=49+48)
ExternalLinkCompiler             235M _ 2%         236M _ 2%    ~     (p=0.538 n=47+44)
LinkWithoutDebugCompiler         179M _ 1%         179M _ 1%    ~     (p=0.775 n=50+50)
[Geo mean]                      74.9M             75.2M       +0.43%

name                      old text-bytes    new text-bytes    delta
HelloSize                       784kB _ 0%        784kB _ 0%  +0.01%  (p=0.000 n=50+50)

name                      old data-bytes    new data-bytes    delta
HelloSize                      13.1kB _ 0%       13.1kB _ 0%    ~     (all equal)

name                      old bss-bytes     new bss-bytes     delta
HelloSize                       206kB _ 0%        206kB _ 0%    ~     (all equal)

name                      old exe-bytes     new exe-bytes     delta
HelloSize                      1.28MB _ 0%       1.28MB _ 0%  +0.00%  (p=0.000 n=50+50)

file      before    after     _       %
addr2line 4006300   4004484   -1816   -0.045%
api       5029956   5029324   -632    -0.013%
asm       4936311   4939423   +3112   +0.063%
buildid   2595059   2595291   +232    +0.009%
cgo       4401029   4397333   -3696   -0.084%
compile   22246677  22246863  +186    +0.001%
cover     4443825   4443065   -760    -0.017%
dist      3366078   3365838   -240    -0.007%
doc       3776391   3776615   +224    +0.006%
fix       3218800   3218648   -152    -0.005%
link      6365321   6365345   +24     +0.000%
nm        3923625   3923857   +232    +0.006%
objdump   4295569   4295041   -528    -0.012%
pack      2390745   2389217   -1528   -0.064%
pprof     12870094  12866942  -3152   -0.024%
test2json 2587265   2587073   -192    -0.007%
trace     9612629   9613981   +1352   +0.014%
vet       6791008   6792072   +1064   +0.016%
total     106856682 106850412 -6270   -0.006%

Update #37608

Change-Id: Ic6206b22fd1faf570be9fd3c2511aa6c4ce38cdb
Reviewed-on: https://go-review.googlesource.com/c/go/+/252937
Trust: fannie zhang <Fannie.Zhang@arm.com>
Run-TryBot: fannie zhang <Fannie.Zhang@arm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2021-03-29 05:50:11 +00:00
Cuong Manh Le
23ffb5b9ae runtime: overwrite existing keys for mapassign_faststr variant
Fixes #45045

Change-Id: Ifcc7bd31591870446ce3e5127489a0b887d413f1
Reviewed-on: https://go-review.googlesource.com/c/go/+/305089
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2021-03-28 03:27:04 +00:00
Pat Gavlin
359f44910f cmd/compile: fix long RMW bit operations on AMD64
Under certain circumstances, the existing rules for bit operations can
produce code that writes beyond its intended bounds. For example,
consider the following code:

    func repro(b []byte, addr, bit int32) {
	    _ = b[3]
	    v := uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24 | 1<<(bit&31)
	    b[0] = byte(v)
	    b[1] = byte(v >> 8)
	    b[2] = byte(v >> 16)
	    b[3] = byte(v >> 24)
    }

Roughly speaking:

1. The expression `1 << (bit & 31)` is rewritten into `(SHLL 1 bit)`
2. The expression `uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 |
   uint32(b[3])<<24` is rewritten into `(MOVLload &b[0])`
3. The statements `b[0] = byte(v) ... b[3] = byte(v >> 24)` are
   rewritten into `(MOVLstore &b[0], v)`
4. `(ORL (SHLL 1, bit) (MOVLload &b[0]))` is rewritten into
   `(BTSL (MOVLload &b[0]) bit)`. This is a valid transformation because
   the destination is a register: in this case, the bit offset is masked
   by the number of bits in the destination register. This is identical
   to the masking performed by `SHL`.
5. `(MOVLstore &b[0] (BTSL (MOVLload &b[0]) bit))` is rewritten into
   `(BTSLmodify &b[0] bit)`. This is an invalid transformation because
   the destination is memory: in this case, the bit offset is not
   masked, and the chosen instruction may write outside its intended
   32-bit location.

These changes fix the invalid rewrite performed in step (5) by
explicitly maksing the bit offset operand to `BT(S|R|C)(L|Q)modify`. In
the example above, the adjusted rules produce
`(BTSLmodify &b[0] (ANDLconst [31] bit))` in step (5).

These changes also add several new rules to rewrite bit sets, toggles,
and clears that are rooted at `(OR|XOR|AND)(L|Q)modify` operators into
appropriate `BT(S|R|C)(L|Q)modify` operators. These rules catch cases
where `MOV(L|Q)store ((OR|XOR|AND)(L|Q) ...)` is rewritten to
`(OR|XOR|AND)(L|Q)modify` before the `(OR|XOR|AND)(L|Q) ...` can be
rewritten to `BT(S|R|C)(L|Q) ...`.

Overall, compilecmp reports small improvements in code size on
darwin/amd64 when the changes to the compiler itself are exlcuded:

file                               before   after    Δ       %
runtime.s                          536464   536412   -52     -0.010%
bytes.s                            32629    32593    -36     -0.110%
strings.s                          44565    44529    -36     -0.081%
os/signal.s                        7967     7959     -8      -0.100%
cmd/vendor/golang.org/x/sys/unix.s 81686    81678    -8      -0.010%
math/big.s                         188235   188253   +18     +0.010%
cmd/link/internal/loader.s         89295    89056    -239    -0.268%
cmd/link/internal/ld.s             633551   633232   -319    -0.050%
cmd/link/internal/arm.s            18934    18928    -6      -0.032%
cmd/link/internal/arm64.s          31814    31801    -13     -0.041%
cmd/link/internal/riscv64.s        7347     7345     -2      -0.027%
cmd/compile/internal/ssa.s         4029173  4033066  +3893   +0.097%
total                              21298280 21301472 +3192   +0.015%

Change-Id: I2e560548b515865129e1724e150e30540e9d29ce
GitHub-Last-Rev: 9a42bd29a5
GitHub-Pull-Request: golang/go#45242
Reviewed-on: https://go-review.googlesource.com/c/go/+/304869
Reviewed-by: Keith Randall <khr@golang.org>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
2021-03-26 19:40:37 +00:00
fanzha02
3a0061822e cmd/compile: add arm64 rules to optimize go codes to constant 0
Optimize the following codes to constant 0.

  function shift (x uint32) uint64 {
    return uint64(x) >> 32
  }

Change-Id: Ida6b39d713cc119ad5a2f01fd54bfd252cf2c975
Reviewed-on: https://go-review.googlesource.com/c/go/+/303830
Trust: fannie zhang <Fannie.Zhang@arm.com>
Run-TryBot: fannie zhang <Fannie.Zhang@arm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-03-26 01:57:35 +00:00
Bryan C. Mills
a95e2ae280 test: skip fixedbugs/issue36705 on Windows
This test is verifying that setting or unsetting an environment
variable in Go via the "os" package makes that change visible to the C
getenv function. The test has been failing on Windows since CL 304569;
it isn't clear to me whether it was running at all before that point.

On Windows the getenv and _putenv C functions are not thread-safe,
so Go's os.Setenv and os.Getenv use the SetEnvironmentVariable and
GetEnvironmentVariable system calls instead. That seems to work fine
in practice; however, changes via SetEnvironmentVariable are
empirically not visible to the C getenv function on certain versions
of Windows.

The MSDN getenv documentation¹ states that ‘getenv operates only on
the data structures accessible to the run-time library and not on the
environment “segment” created for the process by the operating system.
Therefore, programs that use the envp argument to main or wmain may
retrieve invalid information.’ That may be related to what we're
seeing here.

(https://github.com/curl/curl/issues/4774 describes this same behavior
observed in the curl project.)

¹https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/getenv-wgetenv?view=msvc-160#remarks

Updates #36705

Change-Id: I222792f75c650f32c5025b0fa3edab232ff66353
Reviewed-on: https://go-review.googlesource.com/c/go/+/304669
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
2021-03-25 02:50:11 +00:00