Change two-bit stack map entries to encode:
0 = dead
1 = scalar
2 = pointer
3 = multiword
If multiword, the two-bit entry for the following word encodes:
0 = string
1 = slice
2 = iface
3 = eface
That way, during stack scanning we can check if a string
is zero length or a slice has zero capacity. We can avoid
following the contained pointer in those cases. It is safe
to do so because it can never be dereferenced, and it is
desirable to do so because it may cause false retention
of the following block in memory.
Slice feature turned off until issue 7564 is fixed.
Update #7549
LGTM=rsc
R=golang-codereviews, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/76380043
Replaces CL 70000043.
Introduce linkarchinit() from cmd/ld.
For cmd/6c, switch to the amd64p32 linker model if we are building under nacl/amd64p32.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/72010043
From the original description in CL 15770043
The main change here is to consult $GOARCH.
In 6c, when GOOS=nacl, some of the more complex addressing modes must be disabled, and the BP and R15 registers must not be used.
See golang.org/s/go13nacl for design overview.
LGTM=rsc
R=golang-codereviews, gobot, rsc
CC=golang-codereviews
https://golang.org/cl/69020044
We now use the %A, %D, %P, and %R routines from liblink
across the board.
Fixes#7178.
Fixes#7055.
LGTM=iant
R=golang-codereviews, gobot, rsc, dave, iant, remyoudompheng
CC=golang-codereviews
https://golang.org/cl/49170043
- add buffered stdout to all tools and provide to link ctxt.
- avoid extra \n before ! in .6 files written by assemblers
(makes them match the C compilers).
- use linkwriteobj instead of linkouthist+linkwritefuncs.
- in assemblers and C compilers, record pc explicitly in Prog,
for use by liblink.
- in C compilers, preserve jump target links.
- in Go compilers (gsubr.c) attach gotype directly to
corresponding LSym* instead of rederiving from instruction stream.
- in Go compilers, emit just one definition for runtime.zerovalue
from each compilation.
This CL consists entirely of small adjustments.
The heavy lifting is in CL 39680043.
Each depends on the other.
R=golang-dev, dave, iant
CC=golang-dev
https://golang.org/cl/37030045
Preparation for golang.org/s/go13linker work.
This CL does not build by itself. It depends on 35740044
and 35790044 and will be submitted at the same time.
R=iant
CC=golang-dev
https://golang.org/cl/34580044
Preparation for golang.org/s/go13linker work.
This CL does not build by itself. It depends on 35740044
and 35790044 and will be submitted at the same time.
R=iant
CC=golang-dev
https://golang.org/cl/35830043
This change allows the garbage collector to examine stack
slots that are determined as live and containing a pointer
value by the garbage collector. This results in a mean
reduction of 65% in the number of stack slots scanned during
an invocation of "GOGC=1 all.bash".
Unfortunately, this does not yet allow garbage collection to
be precise for the stack slots computed as live. Pointers
confound the determination of what definitions reach a given
instruction. In general, this problem is not solvable without
runtime cost but some advanced cooperation from the compiler
might mitigate common cases.
R=golang-dev, rsc, cshapiro
CC=golang-dev
https://golang.org/cl/14430048
If you thought gcc -ansi -pedantic was pedantic, just wait
until you meet clang -fsanitize=undefined.
I think this addresses all the reported "errors", but we'll
need another run to be sure.
all.bash still passes.
Update #5764
Dave, can you please try again?
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/13334049
cmd/cc: bv.c imports libc.h twice
When using the Plan 9 compiler, the invocation
#include <../ld/textflag.h>
works for the toolchain, but not for the MACH library.
Module cmd/cc/bv.c includes libc.h and "cc.h", which in
turn also includes libc.h. In the Plan 9 context, this
causes a number of duplicate definitions.
R=golang-dev, rsc, r
CC=golang-dev
https://golang.org/cl/13303047
#pragma textflag and #pragma dataflag directives.
Update dataflag directives to use symbols instead of integer constants.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/13310043
Prior to this change, pointer maps encoded the disposition of
a word using a single bit. A zero signaled a non-pointer
value and a one signaled a pointer value. Interface values,
which are a effectively a union type, were conservatively
labeled as a pointer.
This change widens the logical element size of the pointer map
to two bits per word. As before, zero signals a non-pointer
value and one signals a pointer value. Additionally, a two
signals an iface pointer and a three signals an eface pointer.
Following other changes to the runtime, values two and three
will allow a type information to drive interpretation of the
subsequent word so only those interface values containing a
pointer value will be scanned.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/12689046
This change makes the way cc constructs pointer maps closer to
what gc does and is being done in preparation for changes to
the internal content of the pointer map such as a change to
distinguish interface pointers from ordinary pointers.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/12692043
g% 6c ~/x.c
/Users/rsc/x.c:1 duplicate types given: STRUCT s and VOID
/Users/rsc/x.c:1 no return at end of function: f
g%
Fixes#6083.
R=ken2
CC=golang-dev
https://golang.org/cl/12691043
Previously, all word aligned locations in the local variables
area were scanned as conservative roots. With this change, a
bitmap is generated describing the locations of pointer values
in local variables.
With this change the argument bitmap information has been
changed to only store information about arguments. The locals
member, has been removed. In its place, the bitmap data for
local variables is now used to store the size of locals. If
the size is negative, the magnitude indicates the size of the
local variables area.
R=rsc
CC=golang-dev
https://golang.org/cl/12328044
This CL introduces a FUNCDATA number for runtime-specific
garbage collection metadata, changes the C and Go compilers
to emit that metadata, and changes the runtime to expect it.
The old pseudo-instructions that carried this information
are gone, as is the linker code to process them.
R=golang-dev, dvyukov, cshapiro
CC=golang-dev
https://golang.org/cl/11406044
whose argument size is unknown (C vararg functions, and
assembly code without an explicit specification).
We used to use 0 to mean "unknown" and 1 to mean "zero".
Now we use ArgsSizeUnknown (0x80000000) to mean "unknown".
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/11590043
The new code matches the code in cc/lex.c and the #define GETC.
This was causing problems scanning runtime·foo if the leading
· byte was returned by the buffer fill.
R=ken2
CC=golang-dev
https://golang.org/cl/10167043
Changeset 7557a627e9b5 added a temporary stop-gap to silence
a print format warning for %S. This has been reverted.
None of this code is original. It was copied from the latest
Plan 9 compilers.
R=golang-dev, r, rsc
CC=golang-dev
https://golang.org/cl/8630044
If a union contains a pointer, it will mess up the garbage collector, causing memory corruption.
R=golang-dev, dave, nightlyone, adg, dvyukov, bradfitz, minux.ma, r, iant
CC=golang-dev
https://golang.org/cl/8469043
Switch to new pragma names, but leave old ones available for now.
Merge the three cgo-related sections in the .6 files into a single
cgo section.
R=golang-dev, iant, ality
CC=golang-dev
https://golang.org/cl/7424048
Also:
- faster code for example extraction
- simplify handling of command documentation:
all "main" packages are treated as commands
- various minor cleanups along the way
For commands written in Go, any doc.go file containing
documentation must now be part of package main (rather
then package documentation), otherwise the documentation
won't show up in godoc (it will still build, though).
For commands written in C, documentation may still be
in doc.go files defining package documentation, but the
recommended way is to explicitly ignore those files with
a +build ignore constraint to define package main.
Fixes#4806.
R=adg, rsc, dave, bradfitz
CC=golang-dev
https://golang.org/cl/7333046
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
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
Some newer Linux distributions (Ubuntu ARM at least) use a new multiarch
directory organization, where dynamic linker is no longer in the hardcoded
path in our linker.
For example, Ubuntu 12.04 ARM hardfloat places its dynamic linker at
/lib/arm-linux-gnueabihf/ld-linux.so.3
Ref: http://lackof.org/taggart/hacking/multiarch/
Also, to support Debian GNU/kFreeBSD as a FreeBSD variant, we need this capability, so it's part of issue 3533.
This CL add a new pragma (#pragma dynlinker "path") to cc.
R=iant, rsc
CC=golang-dev
https://golang.org/cl/6086043
This makes it possible to inline the prefetch of upcoming
memory addresses during garbage collection, instead of
needing to flush registers, make a function call, and
reload registers. On garbage collection-heavy workloads,
this results in a 5% speedup.
Fixes#3493.
R=dvyukov, ken, r, dave
CC=golang-dev
https://golang.org/cl/5990066
Avoids global array buffer overflows if they are
indexed using some of the values between NTYPE
and NALLTYPE. It is entirely likely that not all of these
are necessary, but this is the C compiler and not worth
worrying much about. This change takes up only a
few more bytes of memory and makes the behavior
deterministic.
Fixes#3078.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5693052
Alternatively, we could expand the ewidth array
in [568]c/txt.c to have NALLTYPES elements and
give all types above NTYPE a width of -1.
I don't think it's worth it since TDOT and TOLD
are the only two type values above NTYPE that
are passed to typ:
$ /tmp/cctypes
cc/dcl.c:683: t->down = typ(TOLD, T);
cc/dcl.c:919: return typ(TDOT, T);
$
Fixes#3063.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5694047
cc: add #pragma textflag to set it
runtime: mark mheap to go into noptr-bss.
remove special case in garbage collector
Remove the ARM from.flag field created by CL 5687044.
The DUPOK flag was already in p->reg, so keep using that.
Otherwise test/nilptr.go creates a very large binary.
Should fix the arm build.
Diagnosed by minux.ma; replacement for CL 5690044.
R=golang-dev, minux.ma, r
CC=golang-dev
https://golang.org/cl/5686060
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
