Fixes #30431

Change-Id: I379e78a1c385942a19e1a10b91d732f9a73899e6
Reviewed-on: https://go-review.googlesource.com/c/164041Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

'go env' is used for many quick operations, such as in go/packages to
query GOARCH and GOMOD. It often is a bottleneck; for example,
go/packages doesn't know whether or not to use Go modules until it has
queried GOMOD.

As such, this go command should be fast. Right now it's slower than it
should be. This commit adds a simple benchmark with os/exec, since we're
particularly interested in the cost of cmd/go's large init function.

Updates #29382.

Change-Id: Ifee6fb9997b9b89565fbfc2739a00c86117b1d37
Reviewed-on: https://go-review.googlesource.com/c/155961
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
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Arm64 has a 32-bit CLZ instruction CLZW, which can be used for intrinsic Len32.
Function LeadingZeros32 calls Len32, with this change, the assembly code of
LeadingZeros32 becomes more concise.

Go code:

func f32(x uint32) { z = bits.LeadingZeros32(x) }

Before:

"".f32 STEXT size=32 args=0x8 locals=0x0 leaf
        0x0000 00000 (test.go:7)        TEXT    "".f32(SB), LEAF|NOFRAME|ABIInternal, $0-8
        0x0004 00004 (test.go:7)        MOVWU   "".x(FP), R0
        0x0008 00008 ($GOROOT/src/math/bits/bits.go:30) CLZ     R0, R0
        0x000c 00012 ($GOROOT/src/math/bits/bits.go:30) SUB     $32, R0, R0
        0x0010 00016 (test.go:7)        MOVD    R0, "".z(SB)
        0x001c 00028 (test.go:7)        RET     (R30)

After:

"".f32 STEXT size=32 args=0x8 locals=0x0 leaf
        0x0000 00000 (test.go:7)        TEXT    "".f32(SB), LEAF|NOFRAME|ABIInternal, $0-8
        0x0004 00004 (test.go:7)        MOVWU   "".x(FP), R0
        0x0008 00008 ($GOROOT/src/math/bits/bits.go:30) CLZW    R0, R0
        0x000c 00012 (test.go:7)        MOVD    R0, "".z(SB)
        0x0018 00024 (test.go:7)        RET     (R30)

Benchmarks:
name              old time/op  new time/op  delta
LeadingZeros-8    2.53ns ± 0%  2.55ns ± 0%   +0.67%  (p=0.000 n=10+10)
LeadingZeros8-8   3.56ns ± 0%  3.56ns ± 0%     ~     (all equal)
LeadingZeros16-8  3.55ns ± 0%  3.56ns ± 0%     ~     (p=0.465 n=10+10)
LeadingZeros32-8  3.55ns ± 0%  2.96ns ± 0%  -16.71%  (p=0.000 n=10+7)
LeadingZeros64-8  2.53ns ± 0%  2.54ns ± 0%     ~     (p=0.059 n=8+10)

Change-Id: Ie5666bb82909e341060e02ffd4e86c0e5d67e90a
Reviewed-on: https://go-review.googlesource.com/c/157000
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This was implemented as part of go/doc, but it's going to be useful in
other packages. In particular, many packages under cmd/go like web and
vcs make somewhat heavy use of global regexes, which add a non-trivial
amount of init work to the cmd/go program.

A lazy wrapper around regexp.Regexp will make it trivial to get rid of
the extra cost with a trivial refactor, so make it possible for other
packages in the repository to make use of it. While naming the package,
give the members better names, such as lazyregexp.New and
lazyregexp.Regexp.

We're also considering adding some form of a lazy API to the public
regexp package, so this internal package will allow us to get some
initial experience across std and cmd.

For #29382.

Change-Id: I30b0e72871d5267c309786f95f4cb15c68b2393d
Reviewed-on: https://go-review.googlesource.com/c/164040
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
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--whole-archive doesn't exist on AIX. It was already removed most of
the time but was still added with c-archive or c-shared buildmodes.

Change-Id: Ia7360638509d4a4d91674b0281ed4b112508a2c9
Reviewed-on: https://go-review.googlesource.com/c/164037
Run-TryBot: Ian Lance Taylor <iant@golang.org>
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This reverts commit ec521467.

Reson for revert: The test cases using slowDst4 and slowDst6 are
fragile. We need to find out a better approach to the trick on the IP
routeability.

Change-Id: I544453886e809d1c7b339673d8f1d5bdef357147
Reviewed-on: https://go-review.googlesource.com/c/163919Reviewed-by: Bryan C. Mills <bcmills@google.com>
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Fixes #29355

Change-Id: I4018d420c8d413b2681744af18ffb65da03ac504
Reviewed-on: https://go-review.googlesource.com/c/155778
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Fixes #30088

Change-Id: I08cec17feddc86bd08532e6b135807e3c8f4c1b2
Reviewed-on: https://go-review.googlesource.com/c/161197
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This commits adds a missing syscall and a missing structure in syscall
package.

Change-Id: I9d630454c56337267f7bbb023e601246e14fc929
Reviewed-on: https://go-review.googlesource.com/c/163978
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If a type switch case expression has failed typechecking, the case body is
likely to also fail with confusing or spurious errors. Suppress
typechecking the case body when this happens.

Fixes #28926

Change-Id: Idfdb9d5627994f2fd90154af1659e9a92bf692c4
Reviewed-on: https://go-review.googlesource.com/c/158617
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Fixes #30253

Change-Id: I0c3d67649ea379b67f3575c1219fe05a04f056ae
Reviewed-on: https://go-review.googlesource.com/c/162859
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If a PE file with invalid optional header size (neither
sizeofOptionalHeader32 nor sizeofOptionalHeader64) is passed to NewFile,
the File.OptionalHeader will be nil which leads to a panic in
(*File).ImportedSymbols().

Fixes #30250

Change-Id: Ie97306de4a0e2dcfdc7b1b599891f574aa63adca
Reviewed-on: https://go-review.googlesource.com/c/162858
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Updates #30055

Change-Id: I3e79dd7592673c5d76568b0bcded6c391c3be6b3
Reviewed-on: https://go-review.googlesource.com/c/163081
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In Go 1.13 we will enable RSA-PSS in TLS 1.2 at the same time as we make
TLS 1.3 enabled by default.

This reverts commit 7ccd3583.

Updates #30055

Change-Id: I6f2ddf7652d1172a6b29f4e335ff3a71a89974bc
Reviewed-on: https://go-review.googlesource.com/c/163080
Run-TryBot: Filippo Valsorda <filippo@golang.org>
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Prior to this change, DATA instructions accepted
the values 1, 2, 4, and 8 as sizes.
The acceptable sizes were further restricted
to 4 and 8 for float constants.

This was both too restrictive and not restrictive enough:
string constants may reasonably have any length,
and address constants should really only accept pointer-length sizes.

Fixes #30269

Change-Id: I06e44ecdf5909eca7b19553861aec1fa39655c2b
Reviewed-on: https://go-review.googlesource.com/c/163747
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
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These are required when testing gccgo.

Change-Id: I6a81d7f4d48292c32a8b3b15ef44d859ab3aa26e
Reviewed-on: https://go-review.googlesource.com/c/163861
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Change-Id: Id2e57bc8e18e062f60c6ac8a58dc15e049352088
GitHub-Last-Rev: 6d33b809cf8a3b5412333b1c3cc237000be8101d
GitHub-Pull-Request: golang/go#30016
Reviewed-on: https://go-review.googlesource.com/c/160440
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Updates #15228.

Change-Id: I1b73defccb4c933d71c408aa31d32af9d1bc4ab8
Reviewed-on: https://go-review.googlesource.com/c/163357Reviewed-by: Matt Layher <mdlayher@gmail.com>

Fix the punctuation and use the proper units for microseconds,
while explaining the incorrect but common variant 'us'.

Change-Id: I9e96694ef27ab4761efccd8616ac7b6700f60d39
Reviewed-on: https://go-review.googlesource.com/c/163917Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
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Consistent logic for handling both duplicate map keys and case values,
and eliminates ad hoc value hashing code.

Also makes cmd/compile consistent with go/types's handling of
duplicate constants (see #28085), which is at least an improvement
over the status quo even if we settle on something different for the
spec.

As a side effect, this also suppresses cmd/compile's warnings about
duplicate nils in (non-interface expression) switch statements, which
was technically never allowed by the spec anyway.

Updates #28085.
Updates #28378.

Change-Id: I176a251e770c3c5bc11c2bf8d1d862db8f252a17
Reviewed-on: https://go-review.googlesource.com/c/152544
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CL 142497 renamed "statictmp_N" to ".stmp_N", but missed an instance
that was added by CL 151498 (submitted between the window that CL
142497 was reviewed/tested and later rebased/merged).

Change-Id: I597ee59dfa40821c7af2881b47e06f84a8140ec8
Reviewed-on: https://go-review.googlesource.com/c/163877
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If the variables passed in to the cofactor arguments of GCD (x, y)
aliased the input arguments (a, b), the previous implementation would
result in incorrect results for y.  This change reorganizes the calculation
so that the only case that need to be handled is when y aliases b, which
can be handled with a simple check.

Tests were added for all of the alias cases for input arguments and and
and irrelevant test case for a previous binary GCD calculation was dropped.

Fixes #30217

Change-Id: Ibe6137f09b3e1ae3c29e3c97aba85b67f33dc169
Reviewed-on: https://go-review.googlesource.com/c/162517
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
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The current ExampleCommentMap might panic if there are more satisfied
comments in the parsed program.

Change-Id: Ibe6943470aa0cfb450dae9fc07c1199acaabef73
GitHub-Last-Rev: c79e98c2868179ea47618b296ce28c5eebc0b99d
GitHub-Pull-Request: golang/go#28587
Reviewed-on: https://go-review.googlesource.com/c/147359
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

This change limits the capacity of the slices of bytes returned by:

- Find
- FindAll
- FindAllSubmatch

to be the same as their length.

Fixes #30169

Change-Id: I07b632757d2bfeab42fce0d42364e2a16c597360
Reviewed-on: https://go-review.googlesource.com/c/161877Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
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This will need to be updated from time to time as new targets are
added to gccgo. But that is better than always returning nil.

Change-Id: I04b8c4d0f8efa38e2a148eb2e38b16b09f0351c3
Reviewed-on: https://go-review.googlesource.com/c/158844
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Reviewed-by: Alan Donovan <adonovan@google.com>
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Set element in slice to nil avoiding memory leak.

Change-Id: I9dbef9a0466407011e326725d3a0b681cd815389
GitHub-Last-Rev: 1bae5d375876a7f146eb04c2a5ba88d079264eb3
GitHub-Pull-Request: golang/go#30386
Reviewed-on: https://go-review.googlesource.com/c/163601
Run-TryBot: Ian Lance Taylor <iant@golang.org>
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This makes the tests slightly faster, though the bulk of the time is
still spent building the test programs.

Also run some tests in parallel.

Updates #26470

Change-Id: Ia5ec2b99831d69c426b43dbab80613aa03e705f5
Reviewed-on: https://go-review.googlesource.com/c/153258Reviewed-by: Austin Clements <austin@google.com>

Updates https://gcc.gnu.org/PR89406

Change-Id: Iccf2760e42e9caa90720b96e74a805a9c0d48f35
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Fixes #30400

Change-Id: Icbd1dda29562afa80c8e37657133a6fe48070ac0
Reviewed-on: https://go-review.googlesource.com/c/163744Reviewed-by: Rob Pike <r@golang.org>

Change-Id: Ia0847790a597c35ebb572db6fc1b7534ecf8f006
GitHub-Last-Rev: 03f039d0abbce0e2a2bf15201948e46354950a22
GitHub-Pull-Request: golang/go#30022
Reviewed-on: https://go-review.googlesource.com/c/160446Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Iaa0e1721996b582bba9509c083755e1f125abb6b
GitHub-Last-Rev: c9b13ec0cdc2b22aafa54706dc6df6113a11712b
GitHub-Pull-Request: golang/go#29996
Reviewed-on: https://go-review.googlesource.com/c/160420
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Also store 64-bit data in lib/time/zoneinfo.zip.

The comments argue that we don't need the 64-bit data until 2037 or
2106, but that turns out not to be the case. We also need them for
dates before December 13, 1901, which is time.Unix(-0x80000000, 0).

Fixes #30099

Change-Id: Ib8c9efb29b7b3c08531ae69912c588209d6320e9
Reviewed-on: https://go-review.googlesource.com/c/161202Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Emit &runtime.zerobase instead of a call to newobject for
allocations of zero sized objects in walk.go.

Fixes #29446

Change-Id: I11b67981d55009726a17c2e582c12ce0c258682e
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Original Printf("%d", hi) obviously doesn't produce
%!d(string=hi) unless somewhere before this code
block you have hi := "hi" somewhere, also this change
maintains consistency with the rest of it

Change-Id: I40d8cca623176dcad66374ba74e3a1f8f975ac9e
GitHub-Last-Rev: 242e9ee6afba7ab22ed2967b0ba01ef18db01ca9
GitHub-Pull-Request: golang/go#30223
Reviewed-on: https://go-review.googlesource.com/c/162541Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This commit adds godoc for Dir.Open function.

Change-Id: Ibc3b22f38660a082802e1f868c5cf9d880fc2801
GitHub-Last-Rev: 774cfd7d8cc61989179956e47d51451135b6c203
GitHub-Pull-Request: golang/go#30353
Reviewed-on: https://go-review.googlesource.com/c/163437Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Icdc980e0dcb5639c49aba5f4f252f33bd207e4fa
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Change-Id: Ib24778f3172c011e6a39ee65dce8764f3cc911ea
GitHub-Last-Rev: 9c617c1e60ac48db67e26e64ce240d3845c0e6ac
GitHub-Pull-Request: golang/go#30284
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Change-Id: I904b8655f21743189814bccf24073b6fbb9fc56d
GitHub-Last-Rev: b032c14394c949f9ad7b18d019a3979d38d4e1fb
GitHub-Pull-Request: golang/go#29997
Reviewed-on: https://go-review.googlesource.com/c/160421Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Ic93a084311de46461ed3b30f4ac2fe11311e74d7
GitHub-Last-Rev: 32fbd63b10d0fa489406333ff6f8b6708974a73c
GitHub-Pull-Request: golang/go#29705
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Avoid name collisions between autogenerated statictmp variables and
user defined global variables.

Fixes #25113

Change-Id: I023eb42a5c2bd2f5352b046d33363faed87084dc
Reviewed-on: https://go-review.googlesource.com/c/142497Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
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