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10 Commits

Author SHA1 Message Date
Matthew Dempsky
6113db0bb4 [dev.regabi] cmd/compile: convert OPANIC argument to interface{} during typecheck
Currently, typecheck leaves arguments to OPANIC as their original
type. This CL changes it to insert implicit OCONVIFACE operations to
convert arguments to `interface{}` like how any other function call
would be handled.

No immediate benefits, other than getting to remove a tiny bit of
special-case logic in order.go's handling of OPANICs. Instead, the
generic code path for handling OCONVIFACE is used, if necessary.
Longer term, this should be marginally helpful for #43753, as it
reduces the number of cases where we need values to be addressable for
runtime calls.

However, this does require adding some hacks to appease existing
tests:

1. We need yet another kludge in inline budgeting, to ensure that
reflect.flag.mustBe stays inlinable for cmd/compile/internal/test's
TestIntendedInlining.

2. Since the OCONVIFACE expressions are now being introduced during
typecheck, they're now visible to escape analysis. So expressions like
"panic(1)" are now seen as "panic(interface{}(1))", and escape
analysis warns that the "interface{}(1)" escapes to the heap. These
have always escaped to heap, just now we're accurately reporting about
it.

(Also, unfortunately fmt.go hides implicit conversions by default in
diagnostics messages, so instead of reporting "interface{}(1) escapes
to heap", it actually reports "1 escapes to heap", which is
confusing. However, this confusing messaging also isn't new.)

Change-Id: Icedf60e1d2e464e219441b8d1233a313770272af
Reviewed-on: https://go-review.googlesource.com/c/go/+/284412
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Trust: Matthew Dempsky <mdempsky@google.com>
2021-01-18 05:55:08 +00:00
Matthew Dempsky
12ee55ba7b [dev.regabi] cmd/compile: stop using Vargen for import/export
Historically, inline function bodies were exported as plain Go source
code, and symbol mangling was a convenient hack because it allowed
variables to be re-imported with largely the same names as they were
originally exported as.

However, nowadays we use a binary format that's more easily extended,
so we can simply serialize all of a function's declared objects up
front, and then refer to them by index later on. This also allows us
to easily report unmangled names all the time (e.g., error message
from issue7921.go).

Fixes #43633.

Change-Id: I46c88f5a47cb921f70ab140976ba9ddce38df216
Reviewed-on: https://go-review.googlesource.com/c/go/+/283193
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
Trust: Dan Scales <danscales@google.com>
Trust: Matthew Dempsky <mdempsky@google.com>
2021-01-12 03:15:18 +00:00
Cuong Manh Le
2c95e3a6a8 cmd/compile: use clearer error message for stuct literal
This CL changes "T literal.M" error message to "T{...}.M". It's clearer
expression and focusing user on actual issue.

Updates #38745

Change-Id: I84b455a86742f37e0bde5bf390aa02984eecc3c9
Reviewed-on: https://go-review.googlesource.com/c/go/+/253677
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2020-09-12 08:31:49 +00:00
Matthew Dempsky
606019cb4b cmd/compile: trim function name prefix from escape diagnostics
This information is redundant with the position information already
provided. Also, no other -m diagnostics print out function name.

While here, report parameter leak diagnostics against the parameter
declaration position rather than the function, and use Warnl for
"moved to heap" messages.

Test cases updated programmatically by removing the first word from
every "no match for" error emitted by run.go:

go run run.go |& \
  sed -E -n 's/^(.*):(.*): no match for `([^ ]* (.*))` in:$/\1!\2!\3!\4/p' | \
  while IFS='!' read -r fn line before after; do
    before=$(echo "$before" | sed 's/[.[\*^$()+?{|]/\\&/g')
    after=$(echo "$after" | sed -E 's/(\&|\\)/\\&/g')
    fn=$(find . -name "${fn}" | head -1)
    sed -i -E -e "${line}s/\"${before}\"/\"${after}\"/" "${fn}"
  done

Passes toolstash-check.

Change-Id: I6e02486b1409e4a8dbb2b9b816d22095835426b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/195040
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2019-09-16 15:30:51 +00:00
Matthew Dempsky
abefcac10a cmd/compile: skip escape analysis diagnostics for OADDR
For most nodes (e.g., OPTRLIT, OMAKESLICE, OCONVIFACE), escape
analysis prints "escapes to heap" or "does not escape" to indicate
whether that node's allocation can be heap or stack allocated.

These messages are also emitted for OADDR, even though OADDR does not
actually allocate anything itself. Moreover, it's redundant because
escape analysis already prints "moved to heap" diagnostics when an
OADDR node like "&x" causes x to require heap allocation.

Because OADDR nodes don't allocate memory, my escape analysis rewrite
doesn't naturally emit the "escapes to heap" / "does not escape"
diagnostics for them. It's also non-trivial to replicate the exact
semantics esc.go uses for OADDR.

Since there are so many of these messages, I'm disabling them in this
CL by themselves. I modified esc.go to suppress the Warnl calls
without any other behavior changes, and then used a shell script to
automatically remove any ERROR messages mentioned by run.go in
"missing error" or "no match for" lines.

Fixes #16300.
Updates #23109.

Change-Id: I3993e2743c3ff83ccd0893f4e73b366ff8871a57
Reviewed-on: https://go-review.googlesource.com/c/go/+/170319
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
2019-04-02 16:34:03 +00:00
David Chase
624e197c71 cmd/compile: decrease inlining call cost from 60 to 57
A Go user made a well-documented request for a slightly
lower threshold.  I tested against a selection of other
people's benchmarks, and saw a tiny benefit (possibly noise)
at equally tiny cost, and no unpleasant surprises observed
in benchmarking.

I.e., might help, doesn't hurt, low risk, request was
delivered on a silver platter.

It did, however, change the behavior of one test because
now bytes.Buffer.Grow is eligible for inlining.

Updates #19348.

Change-Id: I85e3088a4911290872b8c6bda9601b5354c48695
Reviewed-on: https://go-review.googlesource.com/c/151977
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2018-12-01 15:03:28 +00:00
Keith Randall
13baf4b2cd cmd/compile: encourage inlining of functions with single-call bodies
This is a simple tweak to allow a bit more mid-stack inlining.
In cases like this:

func f() {
    g()
}

We'd really like to inline f into its callers. It can't hurt.

We implement this optimization by making calls a bit cheaper, enough
to afford a single call in the function body, but not 2.
The remaining budget allows for some argument modification, or perhaps
a wrapping conditional:

func f(x int) {
    g(x, 0)
}
func f(x int) {
    if x > 0 {
        g()
    }
}

Update #19348

Change-Id: Ifb1ea0dd1db216c3fd5c453c31c3355561fe406f
Reviewed-on: https://go-review.googlesource.com/c/147361
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: David Chase <drchase@google.com>
2018-11-08 17:29:23 +00:00
Brad Fitzpatrick
b3369063e5 test: skip some tests on noopt builder
Adds a new build tag "gcflags_noopt" that can be used in test/*.go
tests.

Fixes #27833

Change-Id: I4ea0ccd9e9e58c4639de18645fec81eb24a3a929
Reviewed-on: https://go-review.googlesource.com/136898
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2018-09-24 20:56:48 +00:00
Iskander Sharipov
b7f9c640b7 test: extend noescape bytes.Buffer test suite
Added some more cases that should be guarded against regression.

Change-Id: I9f1dda2fd0be9b6e167ef1cc018fc8cce55c066c
Reviewed-on: https://go-review.googlesource.com/134017
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-09-07 18:49:12 +00:00
Iskander Sharipov
9c2be4c22d bytes: remove bootstrap array from Buffer
Rationale: small buffer optimization does not work and it has
made things slower since 2014. Until we can make it work,
we should prefer simpler code that also turns out to be more
efficient.

With this change, it's possible to use
NewBuffer(make([]byte, 0, bootstrapSize)) to get the desired
stack-allocated initial buffer since escape analysis can
prove the created slice to be non-escaping.

New implementation key points:

    - Zero value bytes.Buffer performs better than before
    - You can have a truly stack-allocated buffer, and it's not even limited to 64 bytes
    - The unsafe.Sizeof(bytes.Buffer{}) is reduced significantly
    - Empty writes don't cause allocations

Buffer benchmarks from bytes package:

    name                       old time/op    new time/op    delta
    ReadString-8                 9.20µs ± 1%    9.22µs ± 1%     ~     (p=0.148 n=10+10)
    WriteByte-8                  28.1µs ± 0%    26.2µs ± 0%   -6.78%  (p=0.000 n=10+10)
    WriteRune-8                  64.9µs ± 0%    65.0µs ± 0%   +0.16%  (p=0.000 n=10+10)
    BufferNotEmptyWriteRead-8     469µs ± 0%     461µs ± 0%   -1.76%  (p=0.000 n=9+10)
    BufferFullSmallReads-8        108µs ± 0%     108µs ± 0%   -0.21%  (p=0.000 n=10+10)

    name                       old speed      new speed      delta
    ReadString-8               3.56GB/s ± 1%  3.55GB/s ± 1%     ~     (p=0.165 n=10+10)
    WriteByte-8                 146MB/s ± 0%   156MB/s ± 0%   +7.26%  (p=0.000 n=9+10)
    WriteRune-8                 189MB/s ± 0%   189MB/s ± 0%   -0.16%  (p=0.000 n=10+10)

    name                       old alloc/op   new alloc/op   delta
    ReadString-8                 32.8kB ± 0%    32.8kB ± 0%     ~     (all equal)
    WriteByte-8                   0.00B          0.00B          ~     (all equal)
    WriteRune-8                   0.00B          0.00B          ~     (all equal)
    BufferNotEmptyWriteRead-8    4.72kB ± 0%    4.67kB ± 0%   -1.02%  (p=0.000 n=10+10)
    BufferFullSmallReads-8       3.44kB ± 0%    3.33kB ± 0%   -3.26%  (p=0.000 n=10+10)

    name                       old allocs/op  new allocs/op  delta
    ReadString-8                   1.00 ± 0%      1.00 ± 0%     ~     (all equal)
    WriteByte-8                    0.00           0.00          ~     (all equal)
    WriteRune-8                    0.00           0.00          ~     (all equal)
    BufferNotEmptyWriteRead-8      3.00 ± 0%      3.00 ± 0%     ~     (all equal)
    BufferFullSmallReads-8         3.00 ± 0%      2.00 ± 0%  -33.33%  (p=0.000 n=10+10)

The most notable thing in go1 benchmarks is reduced allocs in HTTPClientServer (-1 alloc):

    HTTPClientServer-8           64.0 ± 0%      63.0 ± 0%  -1.56%  (p=0.000 n=10+10)

For more explanations and benchmarks see the referenced issue.

Updates #7921

Change-Id: Ica0bf85e1b70fb4f5dc4f6a61045e2cf4ef72aa3
Reviewed-on: https://go-review.googlesource.com/133715
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-09-06 19:33:18 +00:00