This was disabled in CL 452676 out of an abundance of caution,
but further analysis has shown that the failures were not being
caused by this optimization. Instead the sequence of commits was:
CL 450136 cmd/compile: handle simple inlined calls in staticinit
...
CL 449937 archive/tar, archive/zip: return ErrInsecurePath for unsafe paths
...
CL 451555 cmd/compile: fix static init for inlined calls
The failures in question became compile failures in the first CL
and started building again after the last CL.
But in the interim the code had been broken by the middle CL.
CL 451555 was just the first time that the tests could run and fail.
For #30820.
Change-Id: I65064032355b56fdb43d9731be2f9f32ef6ee600
Reviewed-on: https://go-review.googlesource.com/c/go/+/452817
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
Auto-Submit: Russ Cox <rsc@golang.org>
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This CL adds -d=inlstaticinit to control whether static initialization
of inlined function calls (added in CL 450136) is allowed.
We've needed to fix it once already (CL 451555) and Google-internal
testing is hitting additional failure cases, so putting this
optimization behind a feature flag seems appropriate regardless.
Also, while we diagnose and fix the remaining cases, this CL also
disables the optimization to avoid miscompilations.
Updates #56894.
Change-Id: If52a358ad1e9d6aad1c74fac5a81ff9cfa5a3793
Reviewed-on: https://go-review.googlesource.com/c/go/+/452676
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Fix noopt build break from CL 450136 by not running test.
I can't reproduce the failure locally, but it's entirely reasonable
for this test to fail when optimizations are disabled, so just don't
run it when optimizations are disabled.
Change-Id: I882760fc7373ba0449379f81d295312a6be49be1
Reviewed-on: https://go-review.googlesource.com/c/go/+/450740
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Michael Stapelberg <stapelberg@google.com>
Auto-Submit: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Global variable initializers like
var myErr error = &myError{"msg"}
have been converted to statically initialized data
from the earliest days of Go: there is no init-time
execution or allocation for that line of code.
But if the expression is moved into an inlinable function,
the static initialization no longer happens.
That is, this code has always executed and allocated
at init time, even after we added inlining to the compiler,
which should in theory make this code equivalent to
the original:
func NewError(s string) error { return &myError{s} }
var myErr2 = NewError("msg")
This CL makes the static initialization rewriter understand
inlined functions consisting of a single return statement,
like in this example, so that myErr2 can be implemented as
statically initialized data too, just like myErr, with no init-time
execution or allocation.
A real example of code that benefits from this rewrite is
all globally declared errors created with errors.New, like
package io
var EOF = errors.New("EOF")
Package io no longer has to allocate and initialize EOF each
time a program starts.
Another example of code that benefits is any globally declared
godebug setting (using the API from CL 449504), like
package http
var http2server = godebug.New("http2server")
These are no longer allocated and initialized at program startup either.
The list of functions that are inlined into static initializers when
compiling std and cmd (along with how many times each occurs) is:
cmd/compile/internal/ssa.StringToAux (3)
cmd/compile/internal/walk.mkmapnames (4)
errors.New (360)
go/ast.NewIdent (1)
go/constant.MakeBool (4)
go/constant.MakeInt64 (3)
image.NewUniform (4)
image/color.ModelFunc (11)
internal/godebug.New (12)
vendor/golang.org/x/text/unicode/bidi.newBidiTrie (1)
vendor/golang.org/x/text/unicode/norm.newNfcTrie (1)
vendor/golang.org/x/text/unicode/norm.newNfkcTrie (1)
For the cmd/go binary, this CL cuts the number of init-time
allocations from about 1920 to about 1620 (a 15% reduction).
The total executable code footprint of init functions is reduced
by 24kB, from 137kB to 113kB (an 18% reduction).
The overall binary size is reduced by 45kB,
from 15.335MB to 15.290MB (a 0.3% reduction).
(The binary size savings is larger than the executable code savings
because every byte of executable code also requires corresponding
runtime tables for unwinding, source-line mapping, and so on.)
Also merge test/sinit_run.go, which had stopped testing anything
at all as of CL 161337 (Feb 2019) and initempty.go into a new test
noinit.go.
Fixes#30820.
Change-Id: I52f7275b1ac2a0a32e22c29f9095071c7b1fac20
Reviewed-on: https://go-review.googlesource.com/c/go/+/450136
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Joedian Reid <joedian@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Auto-Submit: Russ Cox <rsc@golang.org>
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Run-TryBot: Russ Cox <rsc@golang.org>
