Rui Ueyama [Wed, 6 Aug 2014 04:10:07 +0000 (21:10 -0700)]
liblink: shorter encoding for zeroing register
Encode MOV $0, %ax as XOR %eax, %eax instead of
XOR %rax, %rax. If an operand register does not
need REX.w bit (i.e. not one of R8-R15), it is
encoded in 2 bytes instead of 3 bytes.
Matthew Dempsky [Wed, 6 Aug 2014 01:16:56 +0000 (18:16 -0700)]
cmd/cgo: fix recursive type mapping
Instead of immediately completing pointer type mappings, add them to
a queue to allow them to be completed later. This fixes issues caused
by Type() returning arbitrary in-progress type mappings.
Matthew Dempsky [Wed, 6 Aug 2014 01:12:32 +0000 (18:12 -0700)]
cmd/cgo: fix handling of defs_linux.go
Instead of including <sys/types.h> to get size_t, instead include
the ISO C standard <stddef.h> header, which defines fewer additional
types at risk of colliding with the user code. In particular, this
prevents collisions between <sys/types.h>'s userspace definitions with
the kernel definitions needed by defs_linux.go.
Also, -cdefs mode uses #pragma pack, so we can keep misaligned fields.
Ian Lance Taylor [Wed, 6 Aug 2014 00:10:15 +0000 (17:10 -0700)]
cmd/cgo: for -godefs, promote first field of anonymous union
Update #6677
When a struct contains an anonymous union, use the type and
name of the first field in the union.
This should make the glibc <sys/resource.h> file work; in that
file struct rusage has fields like
__extension__ union
{
long int ru_maxrss;
__syscall_slong_t __ru_maxrss_word;
};
in which the field that matters is ru_maxrss and
__ru_maxrss_word just exists to advance to the next field on
systems where the kernel uses long long fields but userspace
expects long fields.
Dmitriy Vyukov [Tue, 5 Aug 2014 21:50:37 +0000 (01:50 +0400)]
runtime: cache one GC workbuf in thread-local storage
We call scanblock for lots of small root pieces
e.g. for every stack frame args and locals area.
Every scanblock invocation calls getempty/putempty,
which accesses lock-free stack shared among all worker threads.
One-element local cache allows most scanblock calls
to proceed without accessing the shared stack.
Breaks Camlistore by introducing a datarace. See comments on
https://golang.org/cl/95760043/ for details.
I'll add a new test to lock-in the current behavior in a
subsequent CL.
I don't think Camlistore is particularly unique here: it's doing
the obvious thing to stream a multipart body to a server
using a goroutine feeding the multipart writer.
««« original CL description
mime/multipart: delay reading random source
If a user sets his/her own boundary string with SetBoundary,
we don't need to call randomBoundary at all.
Dmitriy Vyukov [Tue, 5 Aug 2014 18:32:24 +0000 (22:32 +0400)]
runtime: remove type.go
We have an autogenerated version in zruntime_defs.
I am not sure what are the consequences as gdb never printed any values for me.
But it looks unnecessary to manually duplicate it.
Robert Griesemer [Tue, 5 Aug 2014 18:31:32 +0000 (11:31 -0700)]
spec: comma-ok expressions return untyped boolean 2nd result
Technically a language change, this cleanup is a completely
backward compatible change that brings the boolean results
of comma-ok expressions in line with the boolean results of
comparisons: they are now all untyped booleans.
The implementation effort should be minimal (less than a
handfull lines of code, depending how well factored the
implementation of comma-ok expressions is).
Fixes #8189.
LGTM=iant, r, rsc
R=r, rsc, iant, ken
CC=golang-codereviews
https://golang.org/cl/112320045
Ian Lance Taylor [Tue, 5 Aug 2014 02:50:49 +0000 (19:50 -0700)]
test: add test for function type in function literal
The gccgo compiler used to fail this test. This was the root
cause of http://gcc.gnu.org/PR61308 . The fix for the gccgo
compiler is https://golang.org/cl/122020043 .
Brad Fitzpatrick [Mon, 4 Aug 2014 23:12:55 +0000 (16:12 -0700)]
archive/zip: accept bogus trailing zeros in extras
Popular tools both add incorrect trailing zeroes to the zip
extras, and popular tools accept trailing zeros. We seemed to
be the only ones being strict here. Stop being strict. :(
Fixes #8186
LGTM=ruiu, adg, dave
R=adg, ruiu, dave
CC=frohrweck, golang-codereviews
https://golang.org/cl/117550044
runtime: prevent pointless jmp in amd64 and 386 memmove
6a and 8a rearrange memmove such that the fallthrough from move_1or2 to move_0 ends up being a JMP to a RET. Insert an explicit RET to prevent such silliness.
Do the same for memclr as prophylaxis.
benchmark old ns/op new ns/op delta
BenchmarkMemmove1 4.59 4.13 -10.02%
BenchmarkMemmove2 4.58 4.13 -9.83%
runtime: get rid of free
Several reasons:
1. Significantly simplifies runtime.
2. This code proved to be buggy.
3. Free is incompatible with bump-the-pointer allocation.
4. We want to write runtime in Go, Go does not have free.
5. Too much code to free env strings on startup.
Keith Randall [Wed, 30 Jul 2014 18:02:40 +0000 (11:02 -0700)]
runtime: fix stack memory test
Stand-alone this test is fine. Run together with
others, however, the stack used can actually go
negative because other tests are freeing stack
during its execution.
This behavior is new with the new stack allocator.
The old allocator never returned (min-sized) stacks.
This test is fairly poor - it needs to run in
isolation to be accurate. Maybe we should delete it.
Rob Pike [Wed, 30 Jul 2014 17:11:44 +0000 (10:11 -0700)]
runtime: fix assembler macro definitions to be consistent in use of center-dot
The DISPATCH and CALLFN macro definitions depend on an inconsistency
between the internal cpp mini-implementation and the language proper in
whether center-dot is an identifier character. The macro depends on it not
being an identifier character, but the resulting code depends on it being one.
Remove the dependence on the inconsistency by placing the center-dot into
the macro invocation rather that the body.
No semantic change. This is just renaming macro arguments.
Keith Randall [Wed, 30 Jul 2014 16:01:52 +0000 (09:01 -0700)]
runtime: rewrite malloc in Go.
This change introduces gomallocgc, a Go clone of mallocgc.
Only a few uses have been moved over, so there are still
lots of uses from C. Many of these C uses will be moved
over to Go (e.g. in slice.goc), but probably not all.
What should remain of C's mallocgc is an open question.
Mihai Borobocea [Tue, 29 Jul 2014 23:46:53 +0000 (16:46 -0700)]
fmt: measure width in runes not bytes with %c and %q for ints
This is meant to share my progress on Issue 8275, if it's useful to you. I'm not familiar with the formatter's internals, so this change is likely naive.
Change these calls to measure width in runes not bytes:
fmt.Printf("(%5q)\n", '§')
fmt.Printf("(%3c)\n", '§')
Fixes #8275.
LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/104320043
net: prevent spurious on-connect events via epoll on linux
On Linux, adding a socket descriptor to epoll instance before getting
the EINPROGRESS return value from connect system call could be a root
cause of spurious on-connect events.
See golang.org/issue/8276, golang.org/issue/8426 for further information.
Implement the design described in:
https://docs.google.com/document/d/1v4Oqa0WwHunqlb8C3ObL_uNQw3DfSY-ztoA-4wWbKcg/pub
Summary of the changes:
GC uses "2-bits per word" pointer type info embed directly into bitmap.
Scanning of stacks/data/heap is unified.
The old spans types go away.
Compiler generates "sparse" 4-bits type info for GC (directly for GC bitmap).
Linker generates "dense" 2-bits type info for data/bss (the same as stacks use).
Summary of results:
-1680 lines of code total (-1000+ in mgc0.c only)
-25% memory consumption
-3-7% binary size
-15% GC pause reduction
-7% run time reduction
Rob Pike [Tue, 29 Jul 2014 00:24:39 +0000 (17:24 -0700)]
time: make it clearer that the reference time is the reference time.
Because the reference time is the reference time but beginners seem
to think otherwise, make it clearer you can't choose the reference time.
LGTM=josharian, dave
R=golang-codereviews, josharian, dave
CC=golang-codereviews
https://golang.org/cl/117250044
Adam Langley [Mon, 28 Jul 2014 22:46:27 +0000 (15:46 -0700)]
crypto/tls: check curve equation in ECDHE.
This change causes a TLS client and server to verify that received
elliptic curve points are on the expected curve. This isn't actually
necessary in the Go TLS stack, but Watson Ladd has convinced me that
it's worthwhile because it's pretty cheap and it removes the
possibility that some change in the future (e.g. tls-unique) will
depend on it without the author checking that precondition.
Adam Langley [Mon, 28 Jul 2014 21:47:37 +0000 (14:47 -0700)]
encoding/asn1: only omit optional elements matching default value.
ASN.1 elements can be optional, and can have a default value.
Traditionally, Go has omitted elements that are optional and that have
the zero value. I believe that's a bug (see [1]).
This change causes an optional element with a default value to only be
omitted when it has that default value. The previous behaviour of
omitting optional, zero elements with no default is retained because
it's used quite a lot and will break things if changed.
Bobby Powers [Fri, 25 Jul 2014 15:54:09 +0000 (08:54 -0700)]
include/u.h: define _DEFAULT_SOURCE for new glibc
glibc devs have apparently decided _BSD_SOURCE will be
deprecated on Linux, and issue a preprocessor warning if
declaring _BSD_SOURCE without _DEFAULT_SOURCE.
Bobby Powers [Fri, 25 Jul 2014 07:22:58 +0000 (11:22 +0400)]
cmd/gc: don't mark select descriptor as EscNone
selv is created with temp() which calls tempname, which marks
the new n with EscNever, so there is no need to explicitly set
EscNone on the select descriptor.
Andrew Gerrand [Fri, 25 Jul 2014 00:28:39 +0000 (10:28 +1000)]
doc: drop scheme from links that are known to support HTTPS
golang.org now serves HTTPS with a valid cert, so it's reasonable
that users should click through to the HTTPS versions of *.golang.org
and other known sites.
runtime: don't lock mheap on user goroutine
This is bad for 2 reasons:
1. if the code under lock ever grows stack,
it will deadlock as stack growing acquires mheap lock.
2. It currently deadlocks with SetCPUProfileRate:
scavenger locks mheap, receives prof signal and tries to lock prof lock;
meanwhile SetCPUProfileRate locks prof lock and tries to grow stack
(presumably in runtime.unlock->futexwakeup). Boom.
Let's assume that it
Fixes #8407.
runtime: fix unexpected return pc for runtime.newstackcall
With cl/112640043 TestCgoDeadlockCrash episodically print:
unexpected return pc for runtime.newstackcall
After adding debug output I see the following trace:
runtime: unexpected return pc for runtime.newstackcall called from 0xc208011b00
runtime.throw(0x414da86)
src/pkg/runtime/panic.c:523 +0x77
runtime.gentraceback(0x40165fc, 0xba440c28, 0x0, 0xc208d15200, 0xc200000000, 0xc208ddfd20, 0x20, 0x0, 0x0, 0x300)
src/pkg/runtime/traceback_x86.c:185 +0xca4
runtime.callers(0x1, 0xc208ddfd20, 0x20)
src/pkg/runtime/traceback_x86.c:438 +0x98
mcommoninit(0xc208ddfc00)
src/pkg/runtime/proc.c:369 +0x5c
runtime.allocm(0xc208052000)
src/pkg/runtime/proc.c:686 +0xa6
newm(0x4017850, 0xc208052000)
src/pkg/runtime/proc.c:933 +0x27
startm(0xc208052000, 0x100000001)
src/pkg/runtime/proc.c:1011 +0xba
wakep()
src/pkg/runtime/proc.c:1071 +0x57
resetspinning()
src/pkg/runtime/proc.c:1297 +0xa1
schedule()
src/pkg/runtime/proc.c:1366 +0x14b
runtime.gosched0(0xc20808e240)
src/pkg/runtime/proc.c:1465 +0x5b
runtime.newstack()
src/pkg/runtime/stack.c:891 +0x44d
runtime: unexpected return pc for runtime.newstackcall called from 0xc208011b00
runtime.newstackcall(0x4000cbd, 0x4000b80)
src/pkg/runtime/asm_amd64.s:278 +0x6f
I suspect that it can happen on any stack split.
So don't unwind g0 stack.
Also, that comment is lying -- we can traceback w/o mcache,
CPU profiler does that.
liblink: more precise literal word comparison on arm
There are fields in the Addr that do not matter for the
purpose of deciding that the same word is already
in the current literal pool. Copy only the fields that
do matter.
This came up when comparing against the Go version
because the way it is invoked doesn't copy a few fields
(like node) that are never directly used by liblink itself.
Also remove a stray print that is not well-defined in
the new liblink. (Cannot use %D outside of %P, because
%D needs the outer Prog*.)
cmd/gc: mark auxiliary symbols as containing no pointers
They do not, but pretend that they do.
The immediate need is that it breaks the new GC because
these are weird symbols as if with pointers but not necessary
pointer aligned.
cmd/ld: mark hostobj sections as containing no pointers
Currently they are scanned conservatively.
But there is no reason to scan them. C world must not contain
pointers into Go heap. Moreover, we don't have enough information
to emit write barriers nor update pointers there in future.
The immediate need is that it breaks the new GC because
these are weird symbols as if with pointers but not necessary
pointer aligned.
Keith Randall [Tue, 22 Jul 2014 03:56:44 +0000 (20:56 -0700)]
cmd/gc: in the runtime package, don't promote any decls to the heap.
In the runtime, we want to control where allocations happen.
In particular, we don't want the code implementing malloc to
itself trigger a malloc. This change prevents the compiler
from inserting mallocs on our behalf (due to escaping declarations).
This check does not trigger on the current runtime code.