There are various problems, and both Dmitriy and I
will be away for the next week. Make the runtime a bit
more stable while we're gone.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/10848043
fn can clearly hold a closure in memory.
argp/pc point into stack and so can hold
in memory a block that was previously
a large stack serment.
R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/10784043
Depending on net/http means depending on cgo.
When the tree is in a shaky state it's nice to see sync/atomic
pass even if cgo or net causes broken binaries.
R=golang-dev, dave, r
CC=golang-dev
https://golang.org/cl/10753044
This change adds a basic compiler plugin for Go. The plugin
integrates "go build" with Vim's ":make" command and the
quickfix list.
Fixes#5751.
R=golang-dev, dsymonds, niklas.schnelle, 0xjnml
CC=golang-dev
https://golang.org/cl/10466043
After loading a frame of a GIF, check that each pixel
is inside the frame's palette.
Fixes#5401.
R=nigeltao, r
CC=golang-dev
https://golang.org/cl/10597043
A casualty of https://golang.org/cl/10195044.
If x is an 32-bit int and u is a 64-bit ulong,
u = (uint)x // converts to uint before extension, so zero fills
u = (ulong)x // sign-extends
TBR=iant, r
CC=golang-dev
https://golang.org/cl/10814043
Exported inlined functions that perform a string conversion
using a non-exported named type may miss it in export data.
Fixes#5755.
R=rsc, golang-dev, ality, r
CC=golang-dev
https://golang.org/cl/10464043
On amd64 the frames are very close to the limit for a
nosplit (textflag 7) function, in part because the C compiler
does not make any attempt to reclaim space allocated for
completely registerized variables. Avoid a few short-lived
variables to reclaim two words.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/10758043
Keeping the string "compactframe" because that's what
I always search for to find this code. But point to the real place too.
TBR=iant
CC=golang-dev
https://golang.org/cl/10676047
Currently it replaces GOGCTRACE env var (GODEBUG=gctrace=1).
The plan is to extend it with other type of debug tracing,
e.g. GODEBUG=gctrace=1,schedtrace=100.
R=rsc
CC=bradfitz, daniel.morsing, gobot, golang-dev
https://golang.org/cl/10026045
The last patch for preemptive scheduler,
with this change stoptheworld issues preemption
requests every 100us.
Update #543.
R=golang-dev, daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/10264044
The new -coverpkg flag allows computing coverage in
one set of packages while running the tests of a different set.
Also clean up some of the previous CL's recompileForTest,
using packageList to avoid the clumsy recursion.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/10705043
On x86 it is a few words lower on the stack than m->morebuf.sp
so it is a more precise check. Enabling the check requires recording
a valid gp->sched in reflect.call too. This is a good thing in general,
since it will make stack traces during reflect.call work better, and it
may be useful for preemption too.
R=dvyukov
CC=golang-dev
https://golang.org/cl/10709043
runtime.entersyscall() sets g->status = Gsyscall,
then calls runtime.lock() which causes stack split.
runtime.newstack() resets g->status to Grunning.
This will lead to crash during GC (world is not stopped) or GC will scan stack incorrectly.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10696043
Also use 2048-bit RSA keys as default in generate_cert.go,
as recommended by the NIST.
R=golang-dev, rsc, bradfitz
CC=golang-dev
https://golang.org/cl/10676043
On my 64-bit machine, despite being 32-bit code, fixed-base
multiplications are 7.1x faster and arbitary multiplications are 2.6x
faster.
It is difficult to review this change. However, the code is essentially
the same as code that has been open-sourced in Chromium. There it has
been successfully performing P-256 operations for several months on
many machines so the arithmetic of the code should be sound.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10551044
Failure on bot:
http://build.golang.org/log/f4c648906e1289ec2237c1d0880fb1a8b1852a08
««« original CL description
runtime: fix CPU underutilization
runtime.newproc/ready are deliberately sloppy about waking new M's,
they only ensure that there is at least 1 spinning M.
Currently to compensate for that, schedule() checks if the current P
has local work and there are no spinning M's, it wakes up another one.
It does not work if goroutines do not call schedule.
With this change a spinning M wakes up another M when it finds work to do.
It's also not ideal, but it fixes the underutilization.
A proper check would require to know the exact number of runnable G's,
but it's too expensive to maintain.
Fixes#5586.
R=rsc
TBR=rsc
CC=gobot, golang-dev
https://golang.org/cl/9776044
»»»
R=golang-dev
CC=golang-dev
https://golang.org/cl/10692043
runtime.newproc/ready are deliberately sloppy about waking new M's,
they only ensure that there is at least 1 spinning M.
Currently to compensate for that, schedule() checks if the current P
has local work and there are no spinning M's, it wakes up another one.
It does not work if goroutines do not call schedule.
With this change a spinning M wakes up another M when it finds work to do.
It's also not ideal, but it fixes the underutilization.
A proper check would require to know the exact number of runnable G's,
but it's too expensive to maintain.
Fixes#5586.
R=rsc
CC=gobot, golang-dev
https://golang.org/cl/9776044
Current code can print more arguments than necessary
and also incorrectly prints "...".
Update #5723.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10689043
Until now, the goroutine state has been scattered during the
execution of newstack and oldstack. It's all there, and those routines
know how to get back to a working goroutine, but other pieces of
the system, like stack traces, do not. If something does interrupt
the newstack or oldstack execution, the rest of the system can't
understand the goroutine. For example, if newstack decides there
is an overflow and calls throw, the stack tracer wouldn't dump the
goroutine correctly.
For newstack to save a useful state snapshot, it needs to be able
to rewind the PC in the function that triggered the split back to
the beginning of the function. (The PC is a few instructions in, just
after the call to morestack.) To make that possible, we change the
prologues to insert a jmp back to the beginning of the function
after the call to morestack. That is, the prologue used to be roughly:
TEXT myfunc
check for split
jmpcond nosplit
call morestack
nosplit:
sub $xxx, sp
Now an extra instruction is inserted after the call:
TEXT myfunc
start:
check for split
jmpcond nosplit
call morestack
jmp start
nosplit:
sub $xxx, sp
The jmp is not executed directly. It is decoded and simulated by
runtime.rewindmorestack to discover the beginning of the function,
and then the call to morestack returns directly to the start label
instead of to the jump instruction. So logically the jmp is still
executed, just not by the cpu.
The prologue thus repeats in the case of a function that needs a
stack split, but against the cost of the split itself, the extra few
instructions are noise. The repeated prologue has the nice effect of
making a stack split double-check that the new stack is big enough:
if morestack happens to return on a too-small stack, we'll now notice
before corruption happens.
The ability for newstack to rewind to the beginning of the function
should help preemption too. If newstack decides that it was called
for preemption instead of a stack split, it now has the goroutine state
correctly paused if rescheduling is needed, and when the goroutine
can run again, it can return to the start label on its original stack
and re-execute the split check.
Here is an example of a split stack overflow showing the full
trace, without any special cases in the stack printer.
(This one was triggered by making the split check incorrect.)
runtime: newstack framesize=0x0 argsize=0x18 sp=0x6aebd0 stack=[0x6b0000, 0x6b0fa0]
morebuf={pc:0x69f5b sp:0x6aebd8 lr:0x0}
sched={pc:0x68880 sp:0x6aebd0 lr:0x0 ctxt:0x34e700}
runtime: split stack overflow: 0x6aebd0 < 0x6b0000
fatal error: runtime: split stack overflow
goroutine 1 [stack split]:
runtime.mallocgc(0x290, 0x100000000, 0x1)
/Users/rsc/g/go/src/pkg/runtime/zmalloc_darwin_amd64.c:21 fp=0x6aebd8
runtime.new()
/Users/rsc/g/go/src/pkg/runtime/zmalloc_darwin_amd64.c:682 +0x5b fp=0x6aec08
go/build.(*Context).Import(0x5ae340, 0xc210030c71, 0xa, 0xc2100b4380, 0x1b, ...)
/Users/rsc/g/go/src/pkg/go/build/build.go:424 +0x3a fp=0x6b00a0
main.loadImport(0xc210030c71, 0xa, 0xc2100b4380, 0x1b, 0xc2100b42c0, ...)
/Users/rsc/g/go/src/cmd/go/pkg.go:249 +0x371 fp=0x6b01a8
main.(*Package).load(0xc21017c800, 0xc2100b42c0, 0xc2101828c0, 0x0, 0x0, ...)
/Users/rsc/g/go/src/cmd/go/pkg.go:431 +0x2801 fp=0x6b0c98
main.loadPackage(0x369040, 0x7, 0xc2100b42c0, 0x0)
/Users/rsc/g/go/src/cmd/go/pkg.go:709 +0x857 fp=0x6b0f80
----- stack segment boundary -----
main.(*builder).action(0xc2100902a0, 0x0, 0x0, 0xc2100e6c00, 0xc2100e5750, ...)
/Users/rsc/g/go/src/cmd/go/build.go:539 +0x437 fp=0x6b14a0
main.(*builder).action(0xc2100902a0, 0x0, 0x0, 0xc21015b400, 0x2, ...)
/Users/rsc/g/go/src/cmd/go/build.go:528 +0x1d2 fp=0x6b1658
main.(*builder).test(0xc2100902a0, 0xc210092000, 0x0, 0x0, 0xc21008ff60, ...)
/Users/rsc/g/go/src/cmd/go/test.go:622 +0x1b53 fp=0x6b1f68
----- stack segment boundary -----
main.runTest(0x5a6b20, 0xc21000a020, 0x2, 0x2)
/Users/rsc/g/go/src/cmd/go/test.go:366 +0xd09 fp=0x6a5cf0
main.main()
/Users/rsc/g/go/src/cmd/go/main.go:161 +0x4f9 fp=0x6a5f78
runtime.main()
/Users/rsc/g/go/src/pkg/runtime/proc.c:183 +0x92 fp=0x6a5fa0
runtime.goexit()
/Users/rsc/g/go/src/pkg/runtime/proc.c:1266 fp=0x6a5fa8
And here is a seg fault during oldstack:
SIGSEGV: segmentation violation
PC=0x1b2a6
runtime.oldstack()
/Users/rsc/g/go/src/pkg/runtime/stack.c:159 +0x76
runtime.lessstack()
/Users/rsc/g/go/src/pkg/runtime/asm_amd64.s:270 +0x22
goroutine 1 [stack unsplit]:
fmt.(*pp).printArg(0x2102e64e0, 0xe5c80, 0x2102c9220, 0x73, 0x0, ...)
/Users/rsc/g/go/src/pkg/fmt/print.go:818 +0x3d3 fp=0x221031e6f8
fmt.(*pp).doPrintf(0x2102e64e0, 0x12fb20, 0x2, 0x221031eb98, 0x1, ...)
/Users/rsc/g/go/src/pkg/fmt/print.go:1183 +0x15cb fp=0x221031eaf0
fmt.Sprintf(0x12fb20, 0x2, 0x221031eb98, 0x1, 0x1, ...)
/Users/rsc/g/go/src/pkg/fmt/print.go:234 +0x67 fp=0x221031eb40
flag.(*stringValue).String(0x2102c9210, 0x1, 0x0)
/Users/rsc/g/go/src/pkg/flag/flag.go:180 +0xb3 fp=0x221031ebb0
flag.(*FlagSet).Var(0x2102f6000, 0x293d38, 0x2102c9210, 0x143490, 0xa, ...)
/Users/rsc/g/go/src/pkg/flag/flag.go:633 +0x40 fp=0x221031eca0
flag.(*FlagSet).StringVar(0x2102f6000, 0x2102c9210, 0x143490, 0xa, 0x12fa60, ...)
/Users/rsc/g/go/src/pkg/flag/flag.go:550 +0x91 fp=0x221031ece8
flag.(*FlagSet).String(0x2102f6000, 0x143490, 0xa, 0x12fa60, 0x0, ...)
/Users/rsc/g/go/src/pkg/flag/flag.go:563 +0x87 fp=0x221031ed38
flag.String(0x143490, 0xa, 0x12fa60, 0x0, 0x161950, ...)
/Users/rsc/g/go/src/pkg/flag/flag.go:570 +0x6b fp=0x221031ed80
testing.init()
/Users/rsc/g/go/src/pkg/testing/testing.go:-531 +0xbb fp=0x221031edc0
strings_test.init()
/Users/rsc/g/go/src/pkg/strings/strings_test.go:1115 +0x62 fp=0x221031ef70
main.init()
strings/_test/_testmain.go:90 +0x3d fp=0x221031ef78
runtime.main()
/Users/rsc/g/go/src/pkg/runtime/proc.c:180 +0x8a fp=0x221031efa0
runtime.goexit()
/Users/rsc/g/go/src/pkg/runtime/proc.c:1269 fp=0x221031efa8
goroutine 2 [runnable]:
runtime.MHeap_Scavenger()
/Users/rsc/g/go/src/pkg/runtime/mheap.c:438
runtime.goexit()
/Users/rsc/g/go/src/pkg/runtime/proc.c:1269
created by runtime.main
/Users/rsc/g/go/src/pkg/runtime/proc.c:166
rax 0x23ccc0
rbx 0x23ccc0
rcx 0x0
rdx 0x38
rdi 0x2102c0170
rsi 0x221032cfe0
rbp 0x221032cfa0
rsp 0x7fff5fbff5b0
r8 0x2102c0120
r9 0x221032cfa0
r10 0x221032c000
r11 0x104ce8
r12 0xe5c80
r13 0x1be82baac718
r14 0x13091135f7d69200
r15 0x0
rip 0x1b2a6
rflags 0x10246
cs 0x2b
fs 0x0
gs 0x0
Fixes#5723.
R=r, dvyukov, go.peter.90, dave, iant
CC=golang-dev
https://golang.org/cl/10360048
Setenv("AN_ENV_VAR", "") deletes AN_ENV_VAR instead of setting it
to "" at this moment. Also Getenv("AN_ENV_VAR") returns "not found",
if AN_ENV_VAR is "". Change it, so they behave like unix.
Fixes#5610
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/10594043
Makes it easy to ask the simple question, what is the hash of this data?
Also fix the commentary and prints in Sum256.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/10630043
With this CL, go test -short -cover std successfully builds and
runs all the standard package tests. The tests that look a file
line numbers (log and runtime/debug) fail, because cover is
not inserting //line directives. Everything else passes.
ok cmd/api 0.038s coverage: 66.6% of statements
? cmd/cgo [no test files]
ok cmd/fix 0.043s coverage: 27.2% of statements
ok cmd/go 0.063s coverage: 2.4% of statements
? cmd/godoc [no test files]
ok cmd/gofmt 0.085s coverage: 61.3% of statements
? cmd/yacc [no test files]
ok archive/tar 0.023s coverage: 74.2% of statements
ok archive/zip 0.075s coverage: 71.8% of statements
ok bufio 0.149s coverage: 88.2% of statements
ok bytes 0.135s coverage: 90.4% of statements
ok compress/bzip2 0.087s coverage: 85.1% of statements
ok compress/flate 0.632s coverage: 79.3% of statements
ok compress/gzip 0.027s coverage: 76.7% of statements
ok compress/lzw 0.141s coverage: 71.2% of statements
ok compress/zlib 1.123s coverage: 77.2% of statements
ok container/heap 0.020s coverage: 85.8% of statements
ok container/list 0.021s coverage: 92.5% of statements
ok container/ring 0.030s coverage: 86.5% of statements
? crypto [no test files]
ok crypto/aes 0.054s coverage: 54.3% of statements
ok crypto/cipher 0.027s coverage: 68.8% of statements
ok crypto/des 0.041s coverage: 83.8% of statements
ok crypto/dsa 0.027s coverage: 33.1% of statements
ok crypto/ecdsa 0.048s coverage: 48.7% of statements
ok crypto/elliptic 0.030s coverage: 91.6% of statements
ok crypto/hmac 0.019s coverage: 83.3% of statements
ok crypto/md5 0.020s coverage: 78.7% of statements
ok crypto/rand 0.057s coverage: 20.8% of statements
ok crypto/rc4 0.092s coverage: 70.8% of statements
ok crypto/rsa 0.261s coverage: 80.8% of statements
ok crypto/sha1 0.019s coverage: 83.9% of statements
ok crypto/sha256 0.021s coverage: 89.0% of statements
ok crypto/sha512 0.023s coverage: 88.7% of statements
ok crypto/subtle 0.027s coverage: 83.9% of statements
ok crypto/tls 0.833s coverage: 79.7% of statements
ok crypto/x509 0.961s coverage: 74.9% of statements
? crypto/x509/pkix [no test files]
ok database/sql 0.033s coverage: 75.0% of statements
ok database/sql/driver 0.020s coverage: 46.2% of statements
ok debug/dwarf 0.023s coverage: 71.5% of statements
ok debug/elf 0.035s coverage: 58.2% of statements
ok debug/gosym 0.022s coverage: 1.8% of statements
ok debug/macho 0.023s coverage: 63.7% of statements
ok debug/pe 0.024s coverage: 50.5% of statements
ok encoding/ascii85 0.021s coverage: 89.7% of statements
ok encoding/asn1 0.022s coverage: 77.9% of statements
ok encoding/base32 0.022s coverage: 91.4% of statements
ok encoding/base64 0.020s coverage: 90.7% of statements
ok encoding/binary 0.022s coverage: 66.2% of statements
ok encoding/csv 0.022s coverage: 88.5% of statements
ok encoding/gob 0.064s coverage: 82.2% of statements
ok encoding/hex 0.019s coverage: 86.3% of statements
ok encoding/json 0.047s coverage: 77.3% of statements
ok encoding/pem 0.026s coverage: 80.5% of statements
ok encoding/xml 0.039s coverage: 85.0% of statements
ok errors 0.022s coverage: 100.0% of statements
ok expvar 0.048s coverage: 72.0% of statements
ok flag 0.019s coverage: 86.9% of statements
ok fmt 0.062s coverage: 91.2% of statements
ok go/ast 0.028s coverage: 46.3% of statements
ok go/build 0.190s coverage: 75.4% of statements
ok go/doc 0.095s coverage: 76.7% of statements
ok go/format 0.036s coverage: 79.8% of statements
ok go/parser 0.075s coverage: 82.0% of statements
ok go/printer 0.733s coverage: 88.6% of statements
ok go/scanner 0.031s coverage: 86.5% of statements
ok go/token 0.062s coverage: 79.7% of statements
? hash [no test files]
ok hash/adler32 0.029s coverage: 49.0% of statements
ok hash/crc32 0.020s coverage: 64.2% of statements
ok hash/crc64 0.021s coverage: 53.5% of statements
ok hash/fnv 0.018s coverage: 75.5% of statements
ok html 0.022s coverage: 4.5% of statements
ok html/template 0.087s coverage: 83.9% of statements
ok image 0.108s coverage: 67.1% of statements
ok image/color 0.026s coverage: 20.1% of statements
ok image/draw 0.049s coverage: 69.6% of statements
ok image/gif 0.019s coverage: 65.2% of statements
ok image/jpeg 0.197s coverage: 78.6% of statements
ok image/png 0.055s coverage: 56.5% of statements
ok index/suffixarray 0.027s coverage: 82.4% of statements
ok io 0.037s coverage: 83.4% of statements
ok io/ioutil 0.022s coverage: 70.1% of statements
FAIL log 0.020s
ok log/syslog 2.063s coverage: 71.1% of statements
ok math 0.023s coverage: 76.5% of statements
ok math/big 0.235s coverage: 79.2% of statements
ok math/cmplx 0.020s coverage: 66.5% of statements
ok math/rand 0.031s coverage: 69.9% of statements
ok mime 0.022s coverage: 83.0% of statements
ok mime/multipart 0.389s coverage: 76.1% of statements
ok net 2.219s coverage: 58.0% of statements
ok net/http 4.744s coverage: 82.9% of statements
ok net/http/cgi 0.593s coverage: 68.5% of statements
ok net/http/cookiejar 0.038s coverage: 90.3% of statements
ok net/http/fcgi 0.047s coverage: 37.6% of statements
ok net/http/httptest 0.068s coverage: 68.9% of statements
ok net/http/httputil 0.058s coverage: 52.8% of statements
? net/http/pprof [no test files]
ok net/mail 0.025s coverage: 80.3% of statements
ok net/rpc 0.063s coverage: 71.5% of statements
ok net/rpc/jsonrpc 0.047s coverage: 81.3% of statements
ok net/smtp 0.032s coverage: 74.1% of statements
ok net/textproto 0.023s coverage: 66.0% of statements
ok net/url 0.020s coverage: 78.2% of statements
ok os 4.729s coverage: 73.3% of statements
ok os/exec 39.620s coverage: 65.1% of statements
ok os/signal 0.541s coverage: 89.9% of statements
ok os/user 0.022s coverage: 62.2% of statements
ok path 0.018s coverage: 90.8% of statements
ok path/filepath 10.834s coverage: 88.4% of statements
ok reflect 0.055s coverage: 83.2% of statements
ok regexp 0.084s coverage: 75.5% of statements
ok regexp/syntax 0.547s coverage: 85.2% of statements
ok runtime 4.755s coverage: 75.9% of statements
? runtime/cgo [no test files]
FAIL runtime/debug 0.018s
ok runtime/pprof 0.368s coverage: 8.5% of statements
? runtime/race [no test files]
ok sort 0.059s coverage: 97.7% of statements
ok strconv 0.315s coverage: 95.6% of statements
ok strings 0.147s coverage: 96.1% of statements
ok sync 0.083s coverage: 56.7% of statements
ok sync/atomic 0.035s coverage: 0.0% of statements
ok syscall 0.043s coverage: 24.0% of statements
ok testing 0.018s coverage: 24.0% of statements
? testing/iotest [no test files]
ok testing/quick 0.062s coverage: 83.2% of statements
ok text/scanner 0.020s coverage: 91.5% of statements
ok text/tabwriter 0.021s coverage: 90.4% of statements
ok text/template 0.052s coverage: 81.1% of statements
ok text/template/parse 0.024s coverage: 86.1% of statements
ok time 2.431s coverage: 88.8% of statements
ok unicode 0.024s coverage: 92.1% of statements
ok unicode/utf16 0.017s coverage: 97.3% of statements
ok unicode/utf8 0.019s coverage: 97.4% of statements
? unsafe [no test files]
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/10586043
Makes it easy to ask the simple question, what is the hash of this data?
Also mark block as non-escaping.
R=golang-dev, agl
CC=golang-dev
https://golang.org/cl/10624044
Before, some packages disappear silently if the package cannot be imported,
such as if the import statement is unparseable.
Before:
% ls src
foo issue
% go list ./...
_/home/r/bug/src/foo
%
After:
% go list ./...
src/issue/issue.go:3:5: expected 'STRING', found newline
_/home/r/bug/src/foo
%
R=rsc
CC=golang-dev
https://golang.org/cl/10568043
race is more important than arch (moreover race implies x64)
don't know how to test it
R=golang-dev, dave, r
CC=golang-dev
https://golang.org/cl/10484046
Functions without bodies were excluded from the ordering logic,
because when I wrote the ordering logic there was no reason to
analyze them.
But then we added //go:noescape tags that need analysis, and we
didn't update the ordering logic.
So in the absence of good ordering, //go:noescape only worked
if it appeared before the use in the source code.
Fixes#5773.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/10570043
USEFIELD is a special kind of NOP, so treat it like a NOP
when generating the pc-ln table.
There are more invasive fixes that could be applied here.
I am going for minimum number of lines changed.
The smallest test case we know of is five distinct Go files
in four packages, and the bug only happens with
GOEXPERIMENT=fieldtrack enabled, which we don't
normally build with, so the test would never run
meaningfully anyway.
Fixes#5762.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/10495044
If you hg update your client to an earlier CL, then
hg sync will move you back to tip if it pulls anything in,
but it will leave you where you are if it doesn't pull anything in.
That's confusing: make hg sync always update to tip.
R=golang-dev, bradfitz, r, dsymonds
CC=golang-dev
https://golang.org/cl/10456044
Built after adding -Wconversion to the list of compiler
arguments used when building. I believe these are all OK
assuming we will not change the API. There is no effort to
detect overflow due to very long strings.
R=golang-dev, dave, rsc, r
CC=golang-dev
https://golang.org/cl/10195044
Currently more than 1 gorutine can execute raceWrite() in Wait()
in the following scenario:
1. goroutine 1 executes first check of wg.counter, sees that it's == 0
2. goroutine 2 executes first check of wg.counter, sees that it's == 0
3. goroutine 2 locks the mutex, sees that he is the first waiter and executes raceWrite()
4. goroutine 2 block on the semaphore
5. goroutine 3 executes Done() and unblocks goroutine 2
6. goroutine 1 lock the mutex, sees that he is the first waiter and executes raceWrite()
It produces the following false report:
WARNING: DATA RACE
Write by goroutine 35:
sync.raceWrite()
src/pkg/sync/race.go:41 +0x33
sync.(*WaitGroup).Wait()
src/pkg/sync/waitgroup.go:103 +0xae
command-line-arguments_test.TestNoRaceWaitGroupMultipleWait2()
src/pkg/runtime/race/testdata/waitgroup_test.go:156 +0x19a
testing.tRunner()
src/pkg/testing/testing.go:361 +0x108
Previous write by goroutine 36:
sync.raceWrite()
src/pkg/sync/race.go:41 +0x33
sync.(*WaitGroup).Wait()
src/pkg/sync/waitgroup.go:103 +0xae
command-line-arguments_test.func·012()
src/pkg/runtime/race/testdata/waitgroup_test.go:148 +0x4d
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/10424043
