Re-assigning the return value of an atomic operation to the same variable being operated is a common mistake:
x = atomic.AddUint64(&x, 1)
Add this check to go vet.
Fixes#4065.
R=dvyukov, golang-dev, remyoudompheng, rsc
CC=golang-dev
https://golang.org/cl/7097048
This change also resolves some issues with note handling: we now make
sure that there is enough room at the bottom of every goroutine to
execute the note handler, and the `exitstatus' is no longer a global
entity, which resolves some race conditions.
R=rminnich, npe, rsc, ality
CC=golang-dev
https://golang.org/cl/6569068
The dumping routine incorrectly assumed that all incoming
symbols would be non-nil and load through it to retrieve the
symbol name. Instead of using the symbol to retrieve a name,
use the name provided by the caller.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7224043
These changes to test.bash were intended to be submitted with CL 6941058, but were accidentally excluded from the original CL.
R=golang-dev
CC=golang-dev
https://golang.org/cl/7232043
It wasn't removing names from func parameters for func types,
and it was handling "a, b string" as "string", not "string, string".
Fixes#4688
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7181051
Before:
$ go list -f '{{range .Deps}}{{println $.Name .}}{{end}}' math time
math runtime
math unsafe
time errors
time runtime
time sync
time sync/atomic
time syscall
time unsafe
$
After:
$ go list -f '{{range .Deps}}{{println $.Name .}}{{end}}' math time
math runtime
math unsafe
time errors
time runtime
time sync
time sync/atomic
time syscall
time unsafe
$
R=minux.ma, rsc
CC=golang-dev
https://golang.org/cl/7130052
1. note that to use C.free <stdlib.h> must be included
2. can also extract errno from a void C function
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6935045
sizeof(Adr) from 24 bytes down to 20 bytes.
sizeof(Prog) from 84 bytes down to 76 bytes.
5l linking cmd/godoc statistics:
Before:
Maximum resident set size (kbytes): 106668
After:
Maximum resident set size (kbytes): 99412
R=golang-dev, dave
CC=golang-dev
https://golang.org/cl/7100059
Prog
* Remove the unused Prog* dlink
* note that align is also unused, but removing it does not help due to alignment issues.
Saves 4 bytes, sizeof(Prog): 84 => 80.
Sym
* Align {u,}char fields on word boundaries
Saves 4 bytes, sizeof(Sym): 136 => 132.
Tested on linux/arm and freebsd/arm.
R=minux.ma, remyoudompheng, rsc
CC=golang-dev
https://golang.org/cl/7106050
cmd/8g/gsubr.c: unreachable code
cmd/8g/reg.c: overspecifed class
cmd/dist/plan9.c: unused parameter
cmd/gc/fmt.c: stkdelta is now a vlong
cmd/gc/racewalk.c: used but not set
R=golang-dev, seed, rsc
CC=golang-dev
https://golang.org/cl/7067052
The FmtLong flag should only be used with the %D verb
when printing an ATEXT Prog. It was erroneously used
for every Prog except ADATA. This caused a preponderance
of exclamation points, "!!", in the assembly listings.
I also cleaned up the code so that the list.c files look
very similar. Now the real differences are easily spotted
with a simple diff.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7128045
For simplicity, only recognizes expressions of the exact form
"(x << a) | (x >> b)" where x is a variable and a and b are
integer constant expressions that add to x's bit width.
Fixes#4629.
$ cat rotate.c
unsigned int
rotate(unsigned int x)
{
x = (x << 3) | (x >> (sizeof(x) * 8 - 3));
return x;
}
## BEFORE
$ go tool 6c -S rotate.c
(rotate.c:2) TEXT rotate+0(SB),$0-8
(rotate.c:2) MOVL x+0(FP),!!DX
(rotate.c:4) MOVL DX,!!AX
(rotate.c:4) SALL $3,!!AX
(rotate.c:4) MOVL DX,!!CX
(rotate.c:4) SHRL $29,!!CX
(rotate.c:4) ORL CX,!!AX
(rotate.c:5) RET ,!!
(rotate.c:5) RET ,!!
(rotate.c:5) END ,!!
## AFTER
$ go tool 6c -S rotate.c
(rotate.c:2) TEXT rotate+0(SB),$0-8
(rotate.c:4) MOVL x+0(FP),!!AX
(rotate.c:4) ROLL $3,!!AX
(rotate.c:5) RET ,!!
(rotate.c:5) RET ,!!
(rotate.c:5) END ,!!
R=rsc, minux.ma
CC=golang-dev
https://golang.org/cl/7069056
The test case of issue 4585 was not passing due to
miscalculation of memequal args, and the previous fix
does not handle padding at the end of a struct.
Handling of padding at end of structs also fixes the case
of [n]T where T is such a padded struct.
Fixes#4585.
(again)
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7133059
Reference the 80386 compiler documentation now that the
documentation for the 68020 is offline.
R=golang-dev, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/7127053
sse2 is a more precise description of the requirement,
and it matches what people will see in, for example
grep sse2 /proc/cpuinfo # linux
sysctl hw.optional.sse2 # os x
R=golang-dev, dsymonds, iant
CC=golang-dev
https://golang.org/cl/7057050
Also undo revision a5b96b602690 used to workaround the bug.
Fixes#4643.
R=rsc, golang-dev, dave, minux.ma, lucio.dere, bradfitz
CC=golang-dev
https://golang.org/cl/7090043
The peephole optimizer would keep hands off AX and X0 during returns, even though go doesn't return through registers.
R=dave, rsc
CC=golang-dev
https://golang.org/cl/7030046
Changeset f483bfe81114 moved ELF generation to the architecture
independent code and in doing so added a Section* to the Sym
type and an Elf64_Shdr* to the Section type.
This caused the Plan 9 compilers to complain about incompatible
type signatures in the many files that reference the Sym type.
R=rsc, dave
CC=golang-dev
https://golang.org/cl/7057058
Fixes#4186.
Back in the day, before the Go 1.0 release, $GOROOT was mandatory for building from source. Fast forward to now and $GOPATH is mandatory and $GOROOT is optional, and mainly used by those who use the binary distribution in uncommon places.
For example, most novices at least know about `sudo` as they would have used it to install the binary tarball into /usr/local. It is logical they would use the `sudo` hammer to `go get` other Go packages when faced with a permission error talking about the path they just had to use `sudo` on last time.
Even if they had read the documentation and set $GOPATH, go get will not work as expected as `sudo` masks most environment variables.
llucky(~) % ~/go/bin/go env | grep GOPATH
GOPATH="/home/dfc"
lucky(~) % sudo ~/go/bin/go env | grep GOPATH
GOPATH=""
This CL therefore proposes to remove support for using `go get` to download source into $GOROOT.
This CL also proposes an error when GOPATH=$GOROOT, as this is another place where new Go users can get stuck.
Further discussion: https://groups.google.com/d/topic/golang-nuts/VIg3fjHiHRI/discussion
R=rsc, adg, minux.ma
CC=golang-dev
https://golang.org/cl/6941058
The linker split PKGDEF into (prefix, name, def) pairs,
and defines def to begin after a space following the identifier.
This is totally wrong for the following export data:
func "".FunctionName()
var SomethingCompletelyUnrelated int
The linker would parse
name=`"".FunctionName()\n\tvar`
def=`SomethingCompletelyUnrelated int`
since there is no space after FunctionName.
R=minux.ma, rsc
CC=golang-dev
https://golang.org/cl/7068051
Our source no longer needs these flags set to build cleanly using clang.
Tested with
* Ubuntu clang version 3.0-6ubuntu3 (tags/RELEASE_30/final) (based on LLVM 3.0) on i386
* clang version 3.2 (tags/RELEASE_32/final) on amd64 cross compiling all platforms
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7058053
A constant node of type uintptr with a nil literal could
happen in two cases: []int(nil)[1:] and
uintptr(unsafe.Pointer(nil)).
Fixes#4614.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7059043
There exists a test case for this condition, but it only runs on unix systems, which neatly dovetails into the code always using ':' as the list separator.
R=adg, iant
CC=golang-dev
https://golang.org/cl/7057052
There's no b in race detector.
The new flag matches the one in the go command
(go test -race math).
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/7072043
bytes.Equal is simpler to read and should also be faster because
of short-circuiting and assembly implementations.
Change generated automatically using:
gofmt -r 'bytes.Compare(a, b) == 0 -> bytes.Equal(a, b)'
gofmt -r 'bytes.Compare(a, b) != 0 -> !bytes.Equal(a, b)'
R=golang-dev, dave, adg, rsc
CC=golang-dev
https://golang.org/cl/7038051
This CL adds a flag parser that matches the semantics of Go's
package flag. It also changes the linkers and compilers to use
the new flag parser.
Command lines that used to work, like
8c -FVw
6c -Dfoo
5g -I/foo/bar
now need to be split into separate arguments:
8c -F -V -w
6c -D foo
5g -I /foo/bar
The new spacing will work with both old and new tools.
The new parser also allows = for arguments, as in
6c -D=foo
5g -I=/foo/bar
but that syntax will not work with the old tools.
In addition to matching standard Go binary flag parsing,
the new flag parser generates more detailed usage messages
and opens the door to long flag names.
The recently added gc flag -= has been renamed -complete.
R=remyoudompheng, daniel.morsing, minux.ma, iant
CC=golang-dev
https://golang.org/cl/7035043
More cleanup in preparation for fixing issue 4069.
This CL replaces the three nearly identical copies of the
asmb ELF code with a single asmbelf function in elf.c.
In addition to the ELF code movement, remove the elfstr
array in favor of a simpler lookup, and identify sections by
name throughout instead of computing fragile indices.
The CL also replaces the three nearly identical copies of the
genasmsym code with a single genasmsym function in lib.c.
The ARM linker still compiles and generates binaries,
but I haven't tested the binaries. They may not work.
R=ken2
CC=golang-dev
https://golang.org/cl/7062047
The Plan 9 symbol table format defines big-endian symbol values
for portability, but we want to be able to generate an ELF object file
and let the host linker link it, as part of the solution to issue 4069.
The symbol table itself, since it is loaded into memory at run time,
must be filled in by the final host linker, using relocation directives
to set the symbol values. On a little-endian machine, the linker will
only fill in little-endian values during relocation, so we are forced
to use little-endian symbol values.
To preserve most of the original portability of the symbol table
format, we make the table itself say whether it uses big- or
little-endian values. If the table begins with the magic sequence
fe ff ff ff 00 00
then the actual table begins after those six bytes and contains
little-endian symbol values. Otherwise, the table is in the original
format and contains big-endian symbol values. The magic sequence
looks like an "end of table" entry (the fifth byte is zero), so legacy
readers will see a little-endian table as an empty table.
All the gc architectures are little-endian today, so the practical
effect of this CL is to make all the generated tables little-endian,
but if a big-endian system comes along, ld will not generate
the magic sequence, and the various readers will fall back to the
original big-endian interpretation.
R=ken2
CC=golang-dev
https://golang.org/cl/7066043
A few USED(xxx) additions and a couple of deletions of variable
initialisations that go unused. One questionable correction,
mirrored in 8l/asm.c, where the result of invocation of a function
shouldn't be used.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6736054
A new environment variable GO386 is introduced to choose between
code generation targeting 387 or SSE2. No auto-detection is
performed and the setting defaults to 387 to preserve previous
behaviour.
The patch is a reorganization of CL6549052 by rsc.
Fixes#3912.
R=minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6962043
Unnamed types like structs with embedded fields can have methods.
These methods are generated on-the-fly by the compiler and
it may happen for identical types in different packages.
The linker must accept these multiple definitions.
Fixes#4590.
R=golang-dev, rsc
CC=golang-dev, remy
https://golang.org/cl/7030051
Before this CL, defining the variable worked fine, but then when
the implicit package-level init func was created, that caused a
name collision and a confusing error about the redeclaration.
Also add a test for issue 3705 (func init() needs body).
Fixes#4517.
R=ken2
CC=golang-dev
https://golang.org/cl/7008045
An error during the compilation can be more precise
than an error at link time.
For 'func init', the error happens always: you can't forward
declare an init func because the name gets mangled.
For other funcs, the error happens only with the special
(and never used by hand) -= flag, which tells 6g the
package is pure go.
The go command now passes -= for pure Go packages.
Fixes#3705.
R=ken2
CC=golang-dev
https://golang.org/cl/6996054
Ordinary variable load was assumed to be not worth saving,
but not if one of the function calls later might change
its value.
Fixes#4313.
R=ken2
CC=golang-dev
https://golang.org/cl/6997047
The patch makes the compile user an ordinary package-local
symbol for the name of embedded fields of builtin type.
This is incompatible with the fix delivered for issue 2687
(revision 3c060add43fb) but fixes it in a different way, because
the explicit symbol on the field makes the typechecker able to
find it in lookdot.
Fixes#3552.
R=lvd, rsc, daniel.morsing
CC=golang-dev
https://golang.org/cl/6866047
The typechecking code was doing an extra, unnecessary
indirection.
Fixes#4458.
R=golang-dev, daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/6998051
remove zerostack compiler experiment; will do at link time instead
««« original CL description
cmd/gc: add GOEXPERIMENT=zerostack to clear stack on function entry
This is expensive but it might be useful in cases where
people are suffering from false positives during garbage
collection and are willing to trade the CPU time for getting
rid of the false positives.
On the other hand it only eliminates false positives caused
by other function calls, not false positives caused by dead
temporaries stored in the current function call.
The 5g/6g/8g changes were pulled out of the history, from
the last time we needed to do this (to work around a goto bug).
The code in go.h, lex.c, pgen.c is new but tiny.
R=ken2
CC=golang-dev
https://golang.org/cl/6938073
»»»
R=ken2
CC=golang-dev
https://golang.org/cl/7002051
A fatal error used to happen when escassign-ing a multiple
function return to a single node. However, the situation
naturally appears when using "go f(g())" or "defer f(g())",
because g() is escassign-ed to sink.
Fixes#4529.
R=golang-dev, lvd, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6920060
The OpenBSD ld.so(1) does not currently support PT_TLS and refuses
to load ELF binaries that contain PT_TLS sections. Do not emit PT_TLS
sections - we will handle this appropriately in runtime/cgo instead.
R=golang-dev, minux.ma, iant
CC=golang-dev
https://golang.org/cl/6846064
This is expensive but it might be useful in cases where
people are suffering from false positives during garbage
collection and are willing to trade the CPU time for getting
rid of the false positives.
On the other hand it only eliminates false positives caused
by other function calls, not false positives caused by dead
temporaries stored in the current function call.
The 5g/6g/8g changes were pulled out of the history, from
the last time we needed to do this (to work around a goto bug).
The code in go.h, lex.c, pgen.c is new but tiny.
R=ken2
CC=golang-dev
https://golang.org/cl/6938073
The code:
func main() {
v := make([]int64, 10)
i := 1
_ = v[(i*4)/3]
}
crashes compiler with:
Program received signal SIGSEGV, Segmentation fault.
0x000000000043c274 in walkexpr (np=0x7fffffffc9b8, init=0x0) at src/cmd/gc/walk.c:587
587 *init = concat(*init, n->ninit);
(gdb) bt
#0 0x000000000043c274 in walkexpr (np=0x7fffffffc9b8, init=0x0) at src/cmd/gc/walk.c:587
#1 0x0000000000432d15 in copyexpr (n=0x7ffff7f69a48, t=<optimized out>, init=0x0) at src/cmd/gc/subr.c:2020
#2 0x000000000043f281 in walkdiv (init=0x0, np=0x7fffffffca70) at src/cmd/gc/walk.c:2901
#3 walkexpr (np=0x7ffff7f69760, init=0x0) at src/cmd/gc/walk.c:956
#4 0x000000000043d801 in walkexpr (np=0x7ffff7f69bc0, init=0x0) at src/cmd/gc/walk.c:988
#5 0x000000000043cc9b in walkexpr (np=0x7ffff7f69d38, init=0x0) at src/cmd/gc/walk.c:1068
#6 0x000000000043c50b in walkexpr (np=0x7ffff7f69f50, init=0x0) at src/cmd/gc/walk.c:879
#7 0x000000000043c50b in walkexpr (np=0x7ffff7f6a0c8, init=0x0) at src/cmd/gc/walk.c:879
#8 0x0000000000440a53 in walkexprlist (l=0x7ffff7f6a0c8, init=0x0) at src/cmd/gc/walk.c:357
#9 0x000000000043d0bf in walkexpr (np=0x7fffffffd318, init=0x0) at src/cmd/gc/walk.c:566
#10 0x00000000004402bf in vmkcall (fn=<optimized out>, t=0x0, init=0x0, va=0x7fffffffd368) at src/cmd/gc/walk.c:2275
#11 0x000000000044059a in mkcall (name=<optimized out>, t=0x0, init=0x0) at src/cmd/gc/walk.c:2287
#12 0x000000000042862b in callinstr (np=0x7fffffffd4c8, init=0x7fffffffd568, wr=0, skip=<optimized out>) at src/cmd/gc/racewalk.c:478
#13 0x00000000004288b7 in racewalknode (np=0x7ffff7f68108, init=0x7fffffffd568, wr=0, skip=0) at src/cmd/gc/racewalk.c:287
#14 0x0000000000428781 in racewalknode (np=0x7ffff7f65840, init=0x7fffffffd568, wr=0, skip=0) at src/cmd/gc/racewalk.c:302
#15 0x0000000000428abd in racewalklist (l=0x7ffff7f65840, init=0x0) at src/cmd/gc/racewalk.c:97
#16 0x0000000000428d0b in racewalk (fn=0x7ffff7f5f010) at src/cmd/gc/racewalk.c:63
#17 0x0000000000402b9c in compile (fn=0x7ffff7f5f010) at src/cmd/6g/../gc/pgen.c:67
#18 0x0000000000419f86 in funccompile (n=0x7ffff7f5f010, isclosure=0) at src/cmd/gc/dcl.c:1414
#19 0x0000000000424161 in p9main (argc=<optimized out>, argv=<optimized out>) at src/cmd/gc/lex.c:431
#20 0x0000000000401739 in main (argc=<optimized out>, argv=<optimized out>) at src/lib9/main.c:35
The problem is nil init passed to mkcall().
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6940045
