We need to change the interface value representation for
concurrent garbage collection, so that there is no ambiguity
about whether the data word holds a pointer or scalar.
This CL does NOT make any representation changes.
Instead, it removes representation assumptions from
various pieces of code throughout the tree.
The isdirectiface function in cmd/gc/subr.c is now
the only place that decides that policy.
The policy propagates out from there in the reflect
metadata, as a new flag in the internal kind value.
A follow-up CL will change the representation by
changing the isdirectiface function. If that CL causes
problems, it will be easy to roll back.
Update #8405.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews, r
https://golang.org/cl/129090043
The change to pc-relative addressing will make this illegal.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews, r
https://golang.org/cl/129890043
Update #8527
Fixes, cmd/6g/reg.c:847:24: runtime error: left shift of 1 by 31 places cannot be represented in type 'int'
LGTM=minux, rsc
R=minux, rsc
CC=dvyukov, golang-codereviews
https://golang.org/cl/129290043
type T byte
func (T) String() string { return "X" }
fmt.Sprintf("%s", []T{97, 98, 99, 100}) == "abcd"
fmt.Sprintf("%x", []T{97, 98, 99, 100}) == "61626364"
fmt.Sprintf("%v", []T{97, 98, 99, 100}) == "[X X X X]"
This change makes the last case print correctly.
Before, it would have been "[97 98 99 100]".
Fixes#8360.
LGTM=r
R=r, dan.kortschak
CC=golang-codereviews
https://golang.org/cl/129330043
Improve performance of move-to-front by using cache-friendly
copies instead of doubly-linked list. Simplify so that the
underlying slice is the object. Remove the n=0 special case,
which was actually slower with the copy approach.
benchmark old ns/op new ns/op delta
BenchmarkDecodeDigits 26429714 23859699 -9.72%
BenchmarkDecodeTwain 76684510 67591946 -11.86%
benchmark old MB/s new MB/s speedup
BenchmarkDecodeDigits 1.63 1.81 1.11x
BenchmarkDecodeTwain 1.63 1.85 1.13x
Updates #6754.
LGTM=adg, agl, josharian
R=adg, agl, josharian
CC=golang-codereviews
https://golang.org/cl/131840043
Currently we do the following dance after sweeping a span:
1. lock mcentral
2. remove the span from a list
3. unlock mcentral
4. unmark span
5. lock mheap
6. insert the span into heap
7. unlock mheap
8. lock mcentral
9. observe empty list
10. unlock mcentral
11. lock mheap
12. grab the span
13. unlock mheap
14. mark span
15. lock mcentral
16. insert the span into empty list
17. unlock mcentral
This change short-circuits this sequence to nothing,
that is, we just cache and use the span after sweeping.
This gives us functionality similar (even better) to tcmalloc's transfer cache.
benchmark old ns/op new ns/op delta
BenchmarkMalloc8 22.2 19.5 -12.16%
BenchmarkMalloc16 31.0 26.6 -14.19%
LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews, rlh, rsc
https://golang.org/cl/119550043
Mallocgc must be atomic wrt GC, but for performance reasons
don't acquirem/releasem on fast path. The code does not have
split stack checks, so it can't be preempted by GC.
Functions like roundup/add are inlined. And onM/racemalloc are nosplit.
Also add debug code that checks these assumptions.
benchmark old ns/op new ns/op delta
BenchmarkMalloc8 20.5 17.2 -16.10%
BenchmarkMalloc16 29.5 27.0 -8.47%
BenchmarkMallocTypeInfo8 31.5 27.6 -12.38%
BenchmarkMallocTypeInfo16 34.7 30.9 -10.95%
LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews, rlh, rsc
https://golang.org/cl/123100043
Fixes#8480.
This CL reapplies CL 114420043. This attempt doesn't blow up when encountering hidden symbols.
LGTM=minux
R=minux
CC=golang-codereviews
https://golang.org/cl/128310043
When building golang, the environment variable GOROOT_FINAL can be set
to indicate a different installation location from the build
location. This works fine, except that the goc2c build step embeds
line numbers in the resulting c source files that refer to the build
location, no the install location.
This would not be a big deal, except that in turn the linker uses the
location of runtime/string.goc to embed the gdb script in the
resulting binary and as a net result, the debugger now complains that
the script is outside its load path (it has the install location
configured).
See https://code.google.com/p/go/issues/detail?id=8524 for the full
description.
Fixes#8524.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/128230046
bv.data is an array of uint32s but the code was using
offsets computed for an array of bytes.
Add a test for stack GC info.
Fixes#8531.
LGTM=rsc
R=golang-codereviews
CC=golang-codereviews, khr, rsc
https://golang.org/cl/124450043
E.g., here's the new "go build" output:
$ go build misc/cgo/errors/issue8442.go
# command-line-arguments
could not determine kind of name for C.issue8442foo
gcc errors for preamble:
misc/cgo/errors/issue8442.go:11:19: error: unknown type name 'UNDEF'
Fixes#8442.
LGTM=iant
R=iant, alex.brainman
CC=golang-codereviews
https://golang.org/cl/129160043
In cgo, now that recursive calls to typeConv.Type() always work,
we can more robustly calculate the array sizes based on the size
of our element type.
Also, in debug/dwarf, the decision to call zeroType is made
based on a type's usage within a particular struct, but dwarf.Type
values are cached in typeCache, so the modification might affect
uses of the type in other structs. Current compilers don't appear
to share DWARF type entries for "[]foo" and "[0]foo", but they also
don't consistently share type entries in other cases. Arguably
modifying the types is an improvement in some cases, but varying
translated types according to compiler whims seems like a bad idea.
Lastly, also in debug/dwarf, zeroType only needs to rewrite the
top-level dimension, and only if the rest of the array size is
non-zero.
Fixes#8428.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/127980043
Restore https://golang.org/cl/41040043 after GC rewrite.
Original description:
On the plus side, we don't need to change the bits on malloc and free.
On the downside, we need to mark objects in the free lists during GC.
But the free lists are small at GC time, so it should be a net win.
benchmark old ns/op new ns/op delta
BenchmarkMalloc8 21.9 20.4 -6.85%
BenchmarkMalloc16 31.1 29.6 -4.82%
LGTM=khr
R=khr
CC=golang-codereviews, rlh, rsc
https://golang.org/cl/122280043
Basically this cleanup replaces all the usage usages of strcmp() == 0,
found by the following command line:
$ grep -R strcmp cmd/dist | grep "0"
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/123330043
The file is used by assembly code to define symbols like NOSPLIT.
Having it hidden inside the cmd directory makes it hard to access
outside the standard repository.
Solution: As with a couple of other files used by cgo, copy the
file into the pkg directory and add a -I argument to the assembler
to access it. Thus one can write just
#include "textflag.h"
in .s files.
The names in runtime are not updated because in the boot sequence the
file has not been copied yet when runtime is built. All other .s files
in the repository are updated.
Changes to doc/asm.html, src/cmd/dist/build.c, and src/cmd/go/build.go
are hand-made. The rest are just the renaming done by a global
substitution. (Yay sam).
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/128050043
This allows implementing address-of-global
as a pc-relative address instead of as a
32-bit integer constant.
LGTM=rminnich, iant
R=golang-codereviews, rminnich, iant
CC=golang-codereviews
https://golang.org/cl/128070045
This allows changing the addressing mode for constant
global addresses to use pc-relative addressing.
LGTM=rminnich, iant
R=golang-codereviews, rminnich, iant
CC=golang-codereviews
https://golang.org/cl/129830043
You talked me into it. This and other links should be updated
once the new import paths for the subrepos are established.
LGTM=minux
R=golang-codereviews, minux
CC=golang-codereviews
https://golang.org/cl/124260043
Add a clause to the doc comment for the package and a
paragraph in the compatibility document explaining the
situation.
LGTM=bradfitz, adg, rsc
R=golang-codereviews, adg, bradfitz, minux, rsc
CC=golang-codereviews
https://golang.org/cl/129820043
codeblk and datblk were truncating their
arguments to int32. Don't do that.
LGTM=dvyukov, rminnich
R=iant, dvyukov, rminnich
CC=golang-codereviews
https://golang.org/cl/126050043
See golang.org/s/go14customimport for design.
Added case to deps_test to allow go/build to import regexp.
Not a new dependency, because go/build already imports go/doc
which imports regexp.
Fixes#7453.
LGTM=r
R=r, josharian
CC=golang-codereviews
https://golang.org/cl/124940043
It's unclear why we do this broken double-checked locking.
The mutex is not held for the whole duration of CPU profiling.
Fixes#8365.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/116290043
