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
LGTM=khr
R=golang-codereviews, rsc, christoph, khr
CC=golang-codereviews, rlh
https://golang.org/cl/106260045
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
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.
LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/115290046
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.
[1] https://groups.google.com/d/msg/Golang-nuts/9Ss6o9CW-Yo/KL_V7hFlyOAJFixes#7780.
R=bradfitz
LGTM=bradfitz
R=golang-codereviews, bradfitz, rsc
CC=golang-codereviews, r
https://golang.org/cl/86960045
While we're here, make it lookup the tlsfallback symbol only once.
LGTM=crawshaw
R=golang-codereviews, crawshaw, dave
CC=golang-codereviews
https://golang.org/cl/107430044
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.
Fixes#8396.
LGTM=dvyukov
R=golang-codereviews, dave, dvyukov
CC=golang-codereviews
https://golang.org/cl/112520043
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.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/112650043
Sweepone may be running while a new span is allocating. It
must not see the state updated while the sweepgen is unset.
Fixes#8399
LGTM=dvyukov
R=golang-codereviews, dvyukov
CC=golang-codereviews
https://golang.org/cl/118050043
Following CL 68150047, the goos and goarch
variables are not currently set when the GOOS
and GOARCH environment variables are not set.
This made the content of the build tag to be
ignored in this case.
This CL sets goos and goarch to runtime.GOOS
and runtime.GOARCH when the GOOS and GOARCH
environments variables are not set.
LGTM=aram, bradfitz
R=golang-codereviews, aram, gobot, rsc, dave, bradfitz
CC=golang-codereviews, rsc
https://golang.org/cl/112490043
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.
LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews, khr
https://golang.org/cl/112640043
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.
LGTM=rsc
R=golang-codereviews
CC=golang-codereviews, khr, rsc
https://golang.org/cl/120040043
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*.)
LGTM=minux
R=minux
CC=golang-codereviews
https://golang.org/cl/119000043
This matches Go's fmt.Printf instead of ANSI C's dumb rules.
It makes the -S output from C liblink match Go's liblink.
LGTM=minux
R=minux
CC=golang-codereviews
https://golang.org/cl/112600043
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.
LGTM=rsc
R=golang-codereviews, dave, josharian, khr, rsc
CC=golang-codereviews, iant, khr, rlh
https://golang.org/cl/116060043
I've found this very useful for generating
good test case lists for -short mode for
the disassemblers.
Fixes#7959.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/98150043
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.
LGTM=rsc
R=golang-codereviews, rlh, rsc
CC=golang-codereviews, iant, khr
https://golang.org/cl/117000043
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.
Note: Composite literals are still allowed.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/105280047
So we can tell from a binary which version of
Go built it.
LGTM=minux, rsc
R=golang-codereviews, minux, khr, rsc, dave
CC=golang-codereviews
https://golang.org/cl/117040043
This is more useful than panicking, since otherwise every caller needs
to do the length check before calling; some will forget, and have a
potential submarine crasher as a result. Other implementations of this
functionality do a length check.
This is backward compatible, except if someone has written code that
relies on this panicking with different length args. However, that was
not the case before Go 1.3 either.
Updates #7304.
LGTM=agl
R=agl, minux, hanwen
CC=golang-codereviews
https://golang.org/cl/118750043
In both cases we lie to malloc about the actual size that we need.
In panic we ask for less memory than we are going to use.
In slice we ask for more memory than we are going to use
(potentially asking for a fractional number of elements).
This breaks the new GC.
LGTM=khr
R=golang-codereviews, dave, khr
CC=golang-codereviews, rsc
https://golang.org/cl/116940043
Rewrite gotos that violate Go's stricter rules.
Use uchar* instead of char* in a few places that aren't strings.
Remove dead opcross code from asm5.c.
Declare regstr (in both list6 and list8) static.
LGTM=minux, dave
R=minux, dave
CC=golang-codereviews
https://golang.org/cl/113230043
Even though pointers are 4 bytes the stack frame should be kept
a multiple of 8 bytes so that return addresses pushed on the stack
are properly aligned.
Fixes#8379.
LGTM=dvyukov, minux
R=minux, bradfitz, dvyukov, dave
CC=golang-codereviews
https://golang.org/cl/115840048
We might want to add a go/build.IsInternal(pkg string) bool
later, but this works for now.
LGTM=dave, rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/113300044
These correspond to 2 and 3 word fat copies/clears on 8g, which dominate usage in the stdlib. (70% of copies and 46% of clears are for 2 or 3 words.) I missed these in CL 111350043, which added 2 and 3 word benchmarks for 6g. A follow-up CL will optimize these cases.
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/115160043
I'm improving gccgo's detection of variables that are only set
but not used, and it triggers additional errors on this code.
The new gccgo errors are correct; gc seems to suppress them
due to the other, expected, errors. This change uses the
variables so that no compiler will complain.
gccgo change is https://golang.org/cl/119920043 .
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/116050043
benchmark old ns/op new ns/op delta
BenchmarkSelectUncontended 220 165 -25.00%
BenchmarkSelectContended 209 161 -22.97%
BenchmarkSelectProdCons 1042 904 -13.24%
But more importantly this change will allow
to get rid of free function in runtime.
Fixes#6494.
LGTM=rsc, khr
R=golang-codereviews, rsc, dominik.honnef, khr
CC=golang-codereviews, remyoudompheng
https://golang.org/cl/107670043
