On 6l and 8l, this is a real instruction, guaranteed to
cause an 'undefined instruction' exception.
On 5l, we simulate it as BL to address 0.
The plan is to use it as a signal to the linker that this
point in the instruction stream cannot be reached
(hence the changes to nofollow). This will help the
compiler explain that panicindex and friends do not
return without having to put a list of these functions
in the linker.
R=ken2
CC=golang-dev
https://golang.org/cl/6255064
The old code generated for a bounds check was
CMP
JLT ok
CALL panicindex
ok:
...
The new code is (once the linker finishes with it):
CMP
JGE panic
...
panic:
CALL panicindex
which moves the calls out of line, putting more useful
code in each cache line. This matters especially in tight
loops, such as in Fannkuch. The benefit is more modest
elsewhere, but real.
From test/bench/go1, amd64:
benchmark old ns/op new ns/op delta
BenchmarkBinaryTree17 6096092000 6088808000 -0.12%
BenchmarkFannkuch11 6151404000 4020463000 -34.64%
BenchmarkGobDecode 28990050 28894630 -0.33%
BenchmarkGobEncode 12406310 12136730 -2.17%
BenchmarkGzip 179923 179903 -0.01%
BenchmarkGunzip 11219 11130 -0.79%
BenchmarkJSONEncode 86429350 86515900 +0.10%
BenchmarkJSONDecode 334593800 315728400 -5.64%
BenchmarkRevcomp25M 1219763000 1180767000 -3.20%
BenchmarkTemplate 492947600 483646800 -1.89%
And 386:
benchmark old ns/op new ns/op delta
BenchmarkBinaryTree17 6354902000 6243000000 -1.76%
BenchmarkFannkuch11 8043769000 7326965000 -8.91%
BenchmarkGobDecode 19010800 18941230 -0.37%
BenchmarkGobEncode 14077500 13792460 -2.02%
BenchmarkGzip 194087 193619 -0.24%
BenchmarkGunzip 12495 12457 -0.30%
BenchmarkJSONEncode 125636400 125451400 -0.15%
BenchmarkJSONDecode 696648600 685032800 -1.67%
BenchmarkRevcomp25M 2058088000 2052545000 -0.27%
BenchmarkTemplate 602140000 589876800 -2.04%
To implement this, two new instruction forms:
JLT target // same as always
JLT $0, target // branch expected not taken
JLT $1, target // branch expected taken
The linker could also emit the prediction prefixes, but it
does not: expected taken branches are reversed so that the
expected case is not taken (as in example above), and
the default expectaton for such a jump is not taken
already.
R=golang-dev, gri, r, dave
CC=golang-dev
https://golang.org/cl/6248049
As a convenience to people working on the tools,
leave Makefiles that invoke the go dist tool appropriately.
They are not used during the build.
R=golang-dev, bradfitz, n13m3y3r, gustavo
CC=golang-dev
https://golang.org/cl/5636050
Also delete gotest, since it's messy to fix and slated for deletion anyway.
A couple of things outside src can't be tested any more. "go test" will be
fixed and these tests will be re-enabled. They're noisy for now.
Fixes#284.
R=rsc
CC=golang-dev
https://golang.org/cl/5598049
8a/a.h:
. Removed <u.h> and <libc.h> includes as they work better in "a.y".
. Made definition of EOF conditional as it's defined in the Plan 9
header files, but not elsewhere.
8a/a.y:
. Added <u.h> and <libc.h> because <stdio.h> in Plan 9 needs them.
Sequence <u.h>, <stdio.h>, <libc.h> recommended by RSC.
8a/lex.c:
. Added <u.h> and <libc.h> as now needed by "a.h".
. Dropped <ctype.h>.
cc/lexbody:
. exit() -> exits().
. Dropped unwanted incrementation.
cc/macbody:
. Adjusted a few format specifications.
R=rsc
CC=golang-dev
https://golang.org/cl/4644047
Uses of $INCLUDE and $NPROC are left over from Plan 9.
Remove them to avoid causing confusion.
R=golang-dev, r2
CC=golang-dev
https://golang.org/cl/4445079
The object files begin with a header that is
$GOARCH
on a line by itself. This CL changes that header to
go object $GOOS $GOARCH release.2011-01-01 4567+
where the final two fields are the most recent release
tag and the current hg version number.
All objects imported into a Go compilation or linked into an
executable must have the same header line, and that header
line must match the compiler and linker versions.
The effect of this will be that if you update and run all.bash
and then try to link in objects compiled with an earlier version
of the compiler (or invoke the wrong version of the compiler),
you will get an error showing the different headers instead
of perhaps silent incompatibility.
Normal usage with all.bash should be unaffected, because
all.bash deletes all the object files in $GOROOT/pkg/$GOOS_$GOARCH
and cleans all intermediate object files before starting.
This change is intended to diagnose stale objects arising when
users maintaining alternate installation directories forget to
rebuild some of their files after updating.
It should help make the adoption of $GOPATH (CL 3780043)
less error-prone.
R=ken2, r
CC=golang-dev
https://golang.org/cl/4023063
the bash scripts and makefiles for building go didn't take into account
the fact $GOROOT / $GOBIN could both be directories containing whitespaces,
and was not possible to build it in such a situation.
this commit adjusts the various makefiles/scripts to make it aware of that
possibility, and now it builds successfully when using a path with whitespaces
as well.
Fixes#115.
R=rsc, dsymonds1
https://golang.org/cl/157067
add "extern register" support to 8c.
extern register means allocate in the FS-relative segment.
make 8l generate segmented stack checks.
R=ken
OCL=26600
CL=26606
Russ Cox
Shenghou Ma
Adam Langley
Evan Shaw
Darren Elwood
Rob Pike
Hector Chu
Yuval Pavel Zholkover
Jaroslavas Počepko
Dmitriy Vyukov
Lucio De Re
Jeff R. Allen
Luuk van Dijk
Dean Prichard
Sergio Luis O. B. Correia
Phil Pennock