The sticking point on 386 has been the "PC relative" relocations
used to point the garbage collection metadata at the type info.
These aren't in the code segment, and I don't trust that the linker
isn't doing something special that would be okay in code but
not when interpreting the pointers as data (for example, a PLT
jump table would be terrible).
Solve the problem in two steps:
1. Handle "PC relative" relocations within a section internally,
so that the external linker never sees them.
2. Move the gcdata and gcbss tables into the rodata section,
where the type information lives, so that the relocations can
be handled internally.
(To answer the obvious question, we make the gc->type
references relative so that they need not be relocated
individually when generating a shared object file.)
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7629043
Before this CL, running
cd misc/cgo/test
go test -c
readelf --dyn-syms test.test | grep cgoexp
turned up many UNDEF symbols corresponding to symbols actually
in the binary but marked only cgo_export_static. Only symbols
marked cgo_export_dynamic should be listed in this mode.
And if the symbol is going to be listed, it should be listed with its
actual address instead of UNDEF.
The Linux dynamic linker didn't care about the seemingly missing
symbols, but the BSD one did.
This CL eliminates the symbols from the dyn-syms table.
R=golang-dev
TBR=golang-dev
CC=golang-dev
https://golang.org/cl/7624043
- Introduce MaxAlign constant and use in data layout
and ELF section header.
- Allow up to 16-byte alignment for large objects
(will help Keith's hash changes).
- Emit ELF symbol for .rathole (global /dev/null used by 8c).
- Invoke gcc with -m32/-m64 as appropriate.
- Don't invoke gcc if writing the .o file failed.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7563045
Still to do: non-linux and non-amd64.
It may work on other ELF-based amd64 systems too, but untested.
"go test -ldflags -hostobj $GOROOT/misc/cgo/test" passes.
Much may yet change, but this seems a reasonable checkpoint.
R=iant
CC=golang-dev
https://golang.org/cl/7369057
We can enable/disable type checking with a build tag.
Should simplify cutting the go1.1 distribution free of go/types.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7482045
The only check so far is for self-assignments of the form "expr = expr",
but even that found one instance in the standard library.
R=r, adg, mtj, rsc
CC=golang-dev
https://golang.org/cl/7455048
Using -import_runtime_cgo would have worked great except
that it doesn't get passed to the second invocation of cgo,
and that's the one that writes the relevant file.
Fixes ARM build on systems with a different dynamic linker
than the one 5l assumes (like Gentoo).
R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/7432048
Fixes the App Engine version of godoc. The other fix is to duplicate
this code inside appinit.go. I think initHandlers is the right place
to put the strings.Split call, as the notesToShow var is used by
docServer, which is what initHandlers sets up.
R=dsymonds
CC=golang-dev
https://golang.org/cl/7434044
1. when executing a unsupported VFP instruction, the NetBSD kernel somehow
doesn't report SIGILL, and instead just spin and spin, we add a alarm(2)
to detect this case (albeit this is a kernel bug).
2. NetBSD/ARM's VFP11 support is not complete, so temporarily disable it.
3. The default gcc shipped with NetBSD-current mis-optimizes our code
at -O2, so lower the optimization level to -O1 on NetBSD/ARM.
R=dave, rsc
CC=golang-dev
https://golang.org/cl/7286044
swig >= 2.0.9 requires the size of int values to be passed via a command line flag. Should swig complain about the -intgosize not being supported, then alert the user to their outdated version of swig.
Fixes#4756.
R=golang-dev, minux.ma, iant
CC=golang-dev
https://golang.org/cl/7331048
Fixes#4945.
Most examples in this issue now better, but #10 is incomplete and I'm not
certain how to reproduce it. It actually looks like a go/types problem, since
the type being reported is coming directly from that package.
Please reopen the issue if you disagree.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7448046
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
runtime: double-check that symbol table is sorted
If the symbol table is unsorted, the binary search in findfunc
will not find its func, which will make stack traces stop early.
When the garbage collector starts using the stack tracer,
that would be a serious problem.
The unsorted symbol addresses came from from two things:
1. The symbols in an ELF object are not necessarily sorted,
so sort them before adding them to the symbol list.
2. The __i686.get_pc_thunk.bx symbol is present in multiple
object files and was having its address adjusted multiple
times, producing an incorrect address in the symbol table.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7440044
This is the plan for how to make host linking work with
the rest of the system.
There are two complications:
1. It is a goal to preserve the property that pure Go programs
(even ones importing "net") can be compiled without needing
gcc, so that a Go toolchain download works out of the box.
This forces the support for two linking modes: with and without
gcc.
2. It is a goal to allow users with old copies of SWIG to continue
to use those copies. This forces the support for "internal only"
packages. Perhaps it is reasonable to require a new SWIG.
I don't know.
R=iant
CC=golang-dev
https://golang.org/cl/7433043
Also delete bogus tests for f.pkg (does the file have a package) since all
files have a package attached. The tests for pkg.types and pkg.values
suffice.
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/7418043
If all locals are optimized away, the type instructions would stay in the instruction stream. Call fixautoused to scrub the output.
Fixes#4915.
R=rsc
CC=golang-dev
https://golang.org/cl/7385055
The current code uses 64-bit pc-relative on 64-bit systems,
but in ELF linkers there is no such thing, so we cannot
express this in a .o file. Change to 32-bit.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7383055
This CL changes the encoding used for the Go symbol table,
stored in the binary and used at run time. It does not change
any of the semantics or structure: the bits are just packed
a little differently.
The comment at the top of runtime/symtab.c describes the new format.
Compared to the Go 1.0 format, the main changes are:
* Store symbol addresses as full-pointer-sized host-endian values.
(For 6g, this means addresses are 64-bit little-endian.)
* Store other values (frame sizes and so on) varint-encoded.
The second change more than compensates for the first:
for the godoc binary on OS X/amd64, the new symbol table
is 8% smaller than the old symbol table (1,425,668 down from 1,546,276).
This is a required step for allowing the host linker (gcc) to write
the final Go binary, since it will have to fill in the symbol address slots
(so the slots must be host-endian) and on 64-bit systems it may
choose addresses above 4 GB.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7403054
And fix test. Pointer to unsafe.Pointer tests nothing important...
Also identify the incorrect type: go/types.Type is a Stringer.
Also fix a couple of incorrect format verbs found by new printf checker,
now that we can run it on more files.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7385051
pkg/go/doc: move BUG notes from Package.Bugs to the general Package.Notes field.
Removing .Bugs would break existing code so it's left in for now.
R=gri, gri, gary.burd, dsymonds, rsc, kevlar
CC=golang-dev
https://golang.org/cl/7341053
Also restores the checking of _test.go files, which disappeared
as a result of the package-at-a-time change.
Fixes#4895.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7399051
Then mark them with a build tag so they're not compiled into the binary.
They are called test_*.go rather than *_test.go because they are not
for go test. Use make test to test the command.
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/7377052
Composite literals using the &T{} form were incorrectly
exported, leading to weird errors at import time.
Fixes#4879.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7395054
This avoids an allocation when closures are used
as "macros", in Walk idioms, or as argument to defer.
benchmark old ns/op new ns/op delta
BenchmarkSearchWrappers 1171 354 -69.77%
BenchmarkCallClosure 3 3 -12.54%
BenchmarkCallClosure1 119 7 -93.95%
BenchmarkCallClosure2 183 74 -59.18%
BenchmarkCallClosure3 187 75 -59.57%
BenchmarkCallClosure4 187 76 -58.98%
Compared to Go 1:
benchmark old ns/op new ns/op delta
BenchmarkSearchWrappers 3208 354 -88.97%
Fixes#3520.
R=daniel.morsing, bradfitz, minux.ma, dave, rsc
CC=golang-dev
https://golang.org/cl/7397056
Now that the type information is in TYPE instructions
that are not rewritten by the optimization passes,
we don't have to try to preserve the type information
(no longer) attached to MOV instructions.
R=ken2
CC=golang-dev
https://golang.org/cl/7402054
Now that vet does typechecking, it should use only pkg.gofiles, instead
of pkg.allgofiles. Ignored files should not be checked by vet, because
they wouldn't typecheck.
Fixes#4906.
R=rsc, r
CC=golang-dev
https://golang.org/cl/7401051
The type information is (and for years has been) included
as an extra field in the address chunk of an instruction.
Unfortunately, suppose there is a string at a+24(FP) and
we have an instruction reading its length. It will say:
MOVQ x+32(FP), AX
and the type of *that* argument is int (not slice), because
it is the length being read. This confuses the picture seen
by debuggers and now, worse, by the garbage collector.
Instead of attaching the type information to all uses,
emit an explicit list of TYPE instructions with the information.
The TYPE instructions are no-ops whose only role is to
provide an address to attach type information to.
For example, this function:
func f(x, y, z int) (a, b string) {
return
}
now compiles into:
--- prog list "f" ---
0000 (/Users/rsc/x.go:3) TEXT f+0(SB),$0-56
0001 (/Users/rsc/x.go:3) LOCALS ,
0002 (/Users/rsc/x.go:3) TYPE x+0(FP){int},$8
0003 (/Users/rsc/x.go:3) TYPE y+8(FP){int},$8
0004 (/Users/rsc/x.go:3) TYPE z+16(FP){int},$8
0005 (/Users/rsc/x.go:3) TYPE a+24(FP){string},$16
0006 (/Users/rsc/x.go:3) TYPE b+40(FP){string},$16
0007 (/Users/rsc/x.go:3) MOVQ $0,b+40(FP)
0008 (/Users/rsc/x.go:3) MOVQ $0,b+48(FP)
0009 (/Users/rsc/x.go:3) MOVQ $0,a+24(FP)
0010 (/Users/rsc/x.go:3) MOVQ $0,a+32(FP)
0011 (/Users/rsc/x.go:4) RET ,
The { } show the formerly hidden type information.
The { } syntax is used when printing from within the gc compiler.
It is not accepted by the assemblers.
The same type information is now included on global variables:
0055 (/Users/rsc/x.go:15) GLOBL slice+0(SB){[]string},$24(AL*0)
This more accurate type information fixes a bug in the
garbage collector's precise heap collection.
The linker only cares about globals right now, but having the
local information should make things a little nicer for Carl
in the future.
Fixes#4907.
R=ken2
CC=golang-dev
https://golang.org/cl/7395056
Added the command line flag -ex to godoc to print examples in
text output.
Samples from the generated output:
$ godoc -ex strings Index
...
func Index(s, sep string) int
Index returns the index of the first instance of sep in s, or -1 if sep
is not present in s.
Example:
fmt.Println(strings.Index("chicken", "ken"))
fmt.Println(strings.Index("chicken", "dmr"))
// Output:
// 4
// -1
...
$ godoc -ex container/heap
...
package heap
import "container/heap"
Package heap provides heap operations for any type that implements
heap.Interface. A heap is a tree with the property that each node is the
minimum-valued node in its subtree.
Example:
// This example demonstrates an integer heap built using the heap interface.
package heap_test
import (
"container/heap"
"fmt"
...
Example:
// This example demonstrates a priority queue built using the heap interface.
package heap_test
import (
"container/heap"
"fmt"
)
...
Fixes#3587.
R=golang-dev, minux.ma, adg, rsc, gri
CC=golang-dev
https://golang.org/cl/7356043
Or gcc (-fPIC) will complain:
cmd/dist/unix.c: In function ‘cansse2’
cmd/dist/unix.c:774: error: can't find a register in class ‘BREG’ while reloading ‘asm’
cmd/dist/unix.c:774: error: ‘asm’ operand has impossible constraints
This affects bootstrapping on native Darwin/386 where all code is
compiled with -fPIC.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7394047
1. Workaround the smart clang diagnostics with -Qunused-arguments:
clang: error: argument unused during compilation: '-XXX'
2. if "clang -print-libgcc-file-name" returns non-absolute path, don't
provide that on linker command line.
3. Fix dwarf.PtrType.Size() in cmd/cgo as clang doesn't generate
DW_AT_byte_size for pointer types.
4. Workaround warnings for -Wno-unneeded-internal-declaration with
-Wno-unknown-warning-option.
5. Add -Wno-unused-function.
6. enable race detector test on darwin with clang
(at least Apple clang version 1.7 (tags/Apple/clang-77) works).
Requires CL 7354043.
Update #4829
This should fix most parts of the problem, but one glitch still remains.
DWARF generated by newer clang doesn't differentiate these
two function types:
void *malloc(size_t);
void *malloc(unsigned long int);
so you might need to do this to make make.bash pass:
sed -i -e 's/C.malloc(C.size_t/C.malloc(C.ulong/' pkg/os/user/lookup_unix.go
R=golang-dev, dave, iant, rsc
CC=golang-dev
https://golang.org/cl/7351044
We need go/types to discriminate the Error method from
the error interface and the Error method of the testing package.
Fixes#4753.
R=golang-dev, bradfitz, gri
CC=golang-dev
https://golang.org/cl/7396054
This is a simple refactoring of main.go that will enable the type checker
to be used during vetting.
The change has an unimportant effect on the arguments: it now assumes
that all files named explicitly on the command line belong to the same
package. When run by the go command, this was true already.
Also restore a missing parenthesis from an error message.
R=golang-dev, gri, bradfitz
CC=golang-dev
https://golang.org/cl/7393052
Change ARM context register to R7, to get out of the way
of the register allocator during the compilation of the
prologue statements (it wants to use R0 as a temporary).
Step 2 of http://golang.org/s/go11func.
R=ken2
CC=golang-dev
https://golang.org/cl/7369048
The new src argument is ignored during linking
(that is, CALL r1, r2 is identical to CALL r2 for linking),
but it serves as a hint to the 5g/6g/8g optimizer
that the src register is live on entry to the called
function and must be preserved.
It is possible to avoid exposing this fact to the rest of
the toolchain, keeping it entirely within 5g/6g/8g,
but I think it will help to be able to look in object files
and assembly listings and linker -a / -W output to
see CALL instructions are "Go func value" calls and
which are "C function pointer" calls.
R=ken2
CC=golang-dev
https://golang.org/cl/7364045
runtime: add context argument to gogocall
Too many other things use AX, and at least one
(stack zeroing) cannot be moved onto a different
register. Use the less special DX instead.
Preparation for step 2 of http://golang.org/s/go11func.
Nothing interesting here, just split out so that we can
see it's correct before moving on.
R=ken2
CC=golang-dev
https://golang.org/cl/7395050
This significantly speeds up the go tool on
slow file systems (or those with cold caches).
The following numbers were obtained using
an encrypted ext4 file system running on
Linux 3.7.9.
# Before
$ sudo sysctl -w 'vm.drop_caches=3'
$ time go list code.google.com/p/go.net/... | wc -l
9
real 0m16.921s
user 0m0.637s
sys 0m0.317s
# After
$ sudo sysctl -w 'vm.drop_caches=3'
$ time go list code.google.com/p/go.net/... | wc -l
9
real 0m8.175s
user 0m0.220s
sys 0m0.177s
R=rsc, r
CC=golang-dev
https://golang.org/cl/7369044
Previously, the func structure contained an inaccurate value for
the args member and a 0 value for the locals member.
This change populates the func structure with args and locals
values computed by the compiler. The number of args was
already available in the ATEXT instruction. The number of
locals is now passed through in the new ALOCALS instruction.
This change also switches the unit of args and locals to be
bytes, just like the frame member, instead of 32-bit words.
R=golang-dev, bradfitz, cshapiro, dave, rsc
CC=golang-dev
https://golang.org/cl/7399045
Assume people who were going to update to Go 1 have done so.
Those with pre-Go 1 trees remaining will need to update first
to Go 1.0 (using its 'go fix') and then to Go 1.1.
Cuts the cmd/fix test time by 99% (3 seconds to 0.03 seconds).
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7402046
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
The routine that adds an automatic to the stack was
adding ptrsize-1 to the size before rounding up.
That addition would only make sense to turn a round down
into a round up. Before a round up, it just wastes a word.
The effect was that a 6c function with one local and
one two-word function call used (8+8)+(16+8) = 40 bytes
instead of 8+16 = 24 bytes.
The wasted space mostly didn't matter, but one place where
it does matter is when trying to stay within the 128-byte
total frame constraint for #pragma textflag 7 functions.
This only affects the C compilers, not the Go compilers.
5c already had correct code, which is now copied to 6c and 8c.
R=ken2
CC=golang-dev
https://golang.org/cl/7303099
This works with at least one version of clang
that existed at one moment in time.
No guarantees about clangs past or future.
To try:
CC=clang all.bash
It does not work with the Xcode clang,
because that clang fails at printing a useful answer
to:
clang -print-libgcc-file-name
The clang that works prints a full path name for
that command, not just "libgcc.a".
Fixes#4713.
R=iant, minux.ma
CC=golang-dev
https://golang.org/cl/7323068
To make sure that Go code will work when moved to a
system with a case-insensitive file system, like OS X or Windows,
reject any package built from files with names differing
only in case, and also any package built from imported
dependencies with names differing only in case.
Fixes#4773.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7314104
This fixes a regression introduced in changeset 98034d036d03
which added support for producing host object files.
R=rsc, minux.ma
CC=dave, golang-dev
https://golang.org/cl/7307107
- use the new AllErrors flag where appropriate
- unless AllErrors is set, eliminate spurious
errors before they are added to the errors list
(it turns out that reporting spurious errors always
leads to too many uninformative errors after all)
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7323065
The IgnoredGoFiles are already listed in allgofiles,
so they were being run twice. Worse, the ones in
IgnoredGoFiles are not fully qualified paths, so they
weren't being found when executed outside the
package directory.
Fixes#4764.
R=golang-dev, minux.ma, franciscossouza
CC=golang-dev
https://golang.org/cl/7308049
Simplify the internal logic for flags controlling what to vet,
by introducing a map of flags that gathers them all together.
This change should simplify the process of adding further flags.
Add a test for untagged struct literals.
Delete a redundant test that was also in the wrong file.
Clean up some ERROR patterns that weren't working.
"make test" passes again.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7305075
Plan 9 compilers insist this but as we don't have Plan 9
builders, we'd better let gcc check the prototypes.
Inspired by CL 7289050.
R=golang-dev, seed, dave, rsc, lucio.dere
CC=akumar, golang-dev
https://golang.org/cl/7288056
A new comment directive //go:noescape instructs the compiler
that the following external (no body) func declaration should be
treated as if none of its arguments escape to the heap.
Fixes#4099.
R=golang-dev, dave, minux.ma, daniel.morsing, remyoudompheng, adg, agl, iant
CC=golang-dev
https://golang.org/cl/7289048
If the analysis reached a node twice, then the analysis was cut off.
However, if the second arrival is at a lower depth (closer to escaping)
then it is important to repeat the traversal.
The repeating must be cut off at some point to avoid the occasional
infinite recursion. This CL cuts it off as soon as possible while still
passing all tests.
Fixes#4751.
R=ken2
CC=golang-dev, lvd
https://golang.org/cl/7303043
Was not re-walking the new AND node, so that its ullman
count was wrong, so that the code generator attempted to
store values in registers across the call.
Fixes#4752.
R=ken2
CC=golang-dev
https://golang.org/cl/7288054
In cmd/go's 'go help testflag':
* Rewrite list of flags to drop test. prefix on every name.
* Sort list of flags.
* Add example of using -bench to match all benchmarks.
In testing:
* Remove mention of undefined 'CPU group' concept.
Fixes#4488.
Fixes#4508.
R=adg
CC=golang-dev
https://golang.org/cl/7288053
* Avoid treating CALL fn(SB) as justification for introducing
and tracking a registerized variable for fn(SB).
* Remove USED(n) after declaration and zeroing of n.
It was left over from when the compiler emitted more
aggressive set and not used errors, and it was keeping
the optimizer from removing a redundant zeroing of n
when n was a pointer or integer variable.
Update #597.
R=ken2
CC=golang-dev
https://golang.org/cl/7277048
It accepts all the build flags.
Say that instead of making a copy that will go stale.
Fixes#4742.
R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/7229081
Those symbols are only allowed during imports;
the parser may expect them but saying that doesn't help users.
Fixes#3434.
R=ken2
CC=golang-dev
https://golang.org/cl/7277045
For consistency with conversions that look like function calls,
conversions that don't look like function calls now allow an
optional trailing comma.
That is, int(x,) has always been syntactically valid.
Now []int(x,) is valid too.
Fixes#4162.
R=ken2
CC=golang-dev
https://golang.org/cl/7288045
Expressions involving nil, even if they can be evaluated
at compile time, do not count as Go constants and cannot
be used in const initializers.
Fixes#4673.
Fixes#4680.
R=ken2
CC=golang-dev
https://golang.org/cl/7278043
Change the stack unwinding code to compensate for the dynamic
relocation of symbols.
Change the gc instruction GC_CALL to use a relative offset instead of
an absolute address.
R=golang-dev
CC=golang-dev
https://golang.org/cl/7248048
Everybody either gets confused and thinks this is
TrimLeft/TrimRight or does this by hand which gets
repetitive looking.
R=rsc, kevlar
CC=golang-dev
https://golang.org/cl/7239044
Cut out temporary cgo file in error message.
Show C.foo instead of _Ctype_foo.
Before:
x.go:20[/var/folders/00/05_b8000h01000cxqpysvccm000n9d/T/go-build242036121/command-line-arguments/_obj/x.cgo1.go:19]: cannot use tv.Usec (type int32) as type _Ctype___darwin_suseconds_t in assignment
After:
x.go:20: cannot use tv.Usec (type int32) as type C.__darwin_suseconds_t in assignment
Fixes#4255.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7231075
The old version was using go/ast's CommentGroup.Text method,
but that method drops leading blank lines from the result, so that
if the comment looked like one of
//
// syntax error
import "C"
/*
syntax error
*/
import "C"
then the line numbers for the syntax error would be off by the
number of leading blank lines (1 in each of the above cases).
The new text extractor preserves blank lines.
Fixes#4019.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7232071
The Unix and Plan 9 readfile call breset(b) but Windows was not,
leaving dregs in the buffer.
TBR=golang-dev
CC=golang-dev
https://golang.org/cl/7229069
If runtime's proc.c does not compile, cmd/dist used to show
the compile errors in a sea of acid output, making them impossible
to find. Change the command invocation to write the acid output
to a file, so that the errors are the only thing shown on failure.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/7221082
A step toward a fix for issue 4069.
To allow linking with arbitrary host object files, add a linker mode
that can generate a host object file instead of an executable.
Then the host linker can be invoked to generate the final executable.
This CL adds a new -hostobj flag that instructs the linker to write
a host object file instead of an executable.
That is, this works:
go tool 6g x.go
go tool 6l -hostobj -o x.o x.6
ld -e _rt0_amd64_linux x.o
./a.out
as does:
go tool 8g x.go
go tool 8l -hostld ignored -o x.o x.8
ld -m elf_i386 -e _rt0_386_linux x.o
./a.out
Because 5l was never updated to use the standard relocation scheme,
it will take more work to get this working on ARM.
This is a checkpoint of the basic functionality. It does not work
with cgo yet, and cgo is the main reason for the change.
The command-line interface will likely change too.
The gc linker has other information that needs to be returned to
the caller for use when invoking the host linker besides the single
object file.
R=iant, iant
CC=golang-dev
https://golang.org/cl/7060044
* Reject import paths of the form cmd/x/y.
* Reject 'go install' of command outside GOPATH
* Clearer error rejecting 'go install' of package outside GOPATH.
* Name temporary binary for first file in 'go run' list or for test.
* Provide a way to pass -ldflags arguments with spaces.
* Pass all Go files (even +build ignored ones) to go fix, go fmt, go vet.
* Reject 'go run foo_test.go'.
* Silence 'exit 1' prints from 'go tool' invocations.
* Make go test -xxxprofile leave binary behind for analysis.
* Reject ~ in GOPATH except on Windows.
* Get a little less confused by symlinks.
* Document that go test x y z runs three test binaries.
* Fix go test -timeout=0.
* Add -tags flag to 'go list'.
* Use pkg/gccgo_$GOOS_$GOARCH for gccgo output.
Fixes#3389.
Fixes#3500.
Fixes#3503.
Fixes#3760.
Fixes#3941.
Fixes#4007.
Fixes#4032.
Fixes#4074.
Fixes#4127.
Fixes#4140.
Fixes#4311.
Fixes#4568.
Fixes#4576.
Fixes#4702.
R=adg
CC=golang-dev
https://golang.org/cl/7225074
The linker accepts MOVB involving non-byte-addressable
registers, by generating XCHG instructions to AX or BX.
It does not handle the case where nor AX nor BX are available.
See also revision 1470920a2804.
Assembling
TEXT ·Truc(SB),7,$0
MOVB BP, (BX)(AX*1)
RET
gives before:
08048c60 <main.Truc>:
8048c60: 87 dd xchg %ebx,%ebp
8048c62: 88 1c 03 mov %bl,(%ebx,%eax,1)
8048c65: 87 dd xchg %ebx,%ebp
8048c67: c3 ret
and after:
08048c60 <main.Truc>:
8048c60: 87 cd xchg %ecx,%ebp
8048c62: 88 0c 03 mov %cl,(%ebx,%eax,1)
8048c65: 87 cd xchg %ecx,%ebp
8048c67: c3 ret
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7226066
Export data was broken after revision 6b602ab487d6
when -l is specified at least 3 times: it makes the compiler
write out func (*T).Method() declarations in export data, which
is not supported.
Also fix the formatting of recover() in export data. It was
not treated like panic() and was rendered as "<node RECOVER>".
R=golang-dev, lvd, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/7067051
To allow for stdcall decorated names on Windows, two changes were needed:
1. Change the symbol versioning delimiter '@' in cgo's dynimport output to a '#', and in cmd/ld when it parses dynimports.
2. Remove the "@N" decorator from the first argument of cgo's dynimport output (PE only).
Fixes#4607.
R=minux.ma, adg, rsc
CC=golang-dev
https://golang.org/cl/7047043
Re-assigning the return value of an atomic operation to the same variable being operated is a common mistake:
x = atomic.AddUint64(&x, 1)
Add this check to go vet.
Fixes#4065.
R=dvyukov, golang-dev, remyoudompheng, rsc
CC=golang-dev
https://golang.org/cl/7097048
This change also resolves some issues with note handling: we now make
sure that there is enough room at the bottom of every goroutine to
execute the note handler, and the `exitstatus' is no longer a global
entity, which resolves some race conditions.
R=rminnich, npe, rsc, ality
CC=golang-dev
https://golang.org/cl/6569068
The dumping routine incorrectly assumed that all incoming
symbols would be non-nil and load through it to retrieve the
symbol name. Instead of using the symbol to retrieve a name,
use the name provided by the caller.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7224043
These changes to test.bash were intended to be submitted with CL 6941058, but were accidentally excluded from the original CL.
R=golang-dev
CC=golang-dev
https://golang.org/cl/7232043
It wasn't removing names from func parameters for func types,
and it was handling "a, b string" as "string", not "string, string".
Fixes#4688
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7181051
Before:
$ go list -f '{{range .Deps}}{{println $.Name .}}{{end}}' math time
math runtime
math unsafe
time errors
time runtime
time sync
time sync/atomic
time syscall
time unsafe
$
After:
$ go list -f '{{range .Deps}}{{println $.Name .}}{{end}}' math time
math runtime
math unsafe
time errors
time runtime
time sync
time sync/atomic
time syscall
time unsafe
$
R=minux.ma, rsc
CC=golang-dev
https://golang.org/cl/7130052
1. note that to use C.free <stdlib.h> must be included
2. can also extract errno from a void C function
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6935045
sizeof(Adr) from 24 bytes down to 20 bytes.
sizeof(Prog) from 84 bytes down to 76 bytes.
5l linking cmd/godoc statistics:
Before:
Maximum resident set size (kbytes): 106668
After:
Maximum resident set size (kbytes): 99412
R=golang-dev, dave
CC=golang-dev
https://golang.org/cl/7100059
Prog
* Remove the unused Prog* dlink
* note that align is also unused, but removing it does not help due to alignment issues.
Saves 4 bytes, sizeof(Prog): 84 => 80.
Sym
* Align {u,}char fields on word boundaries
Saves 4 bytes, sizeof(Sym): 136 => 132.
Tested on linux/arm and freebsd/arm.
R=minux.ma, remyoudompheng, rsc
CC=golang-dev
https://golang.org/cl/7106050
cmd/8g/gsubr.c: unreachable code
cmd/8g/reg.c: overspecifed class
cmd/dist/plan9.c: unused parameter
cmd/gc/fmt.c: stkdelta is now a vlong
cmd/gc/racewalk.c: used but not set
R=golang-dev, seed, rsc
CC=golang-dev
https://golang.org/cl/7067052
The FmtLong flag should only be used with the %D verb
when printing an ATEXT Prog. It was erroneously used
for every Prog except ADATA. This caused a preponderance
of exclamation points, "!!", in the assembly listings.
I also cleaned up the code so that the list.c files look
very similar. Now the real differences are easily spotted
with a simple diff.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7128045
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
The test case of issue 4585 was not passing due to
miscalculation of memequal args, and the previous fix
does not handle padding at the end of a struct.
Handling of padding at end of structs also fixes the case
of [n]T where T is such a padded struct.
Fixes#4585.
(again)
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7133059
Reference the 80386 compiler documentation now that the
documentation for the 68020 is offline.
R=golang-dev, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/7127053
sse2 is a more precise description of the requirement,
and it matches what people will see in, for example
grep sse2 /proc/cpuinfo # linux
sysctl hw.optional.sse2 # os x
R=golang-dev, dsymonds, iant
CC=golang-dev
https://golang.org/cl/7057050
Also undo revision a5b96b602690 used to workaround the bug.
Fixes#4643.
R=rsc, golang-dev, dave, minux.ma, lucio.dere, bradfitz
CC=golang-dev
https://golang.org/cl/7090043
The peephole optimizer would keep hands off AX and X0 during returns, even though go doesn't return through registers.
R=dave, rsc
CC=golang-dev
https://golang.org/cl/7030046
Changeset f483bfe81114 moved ELF generation to the architecture
independent code and in doing so added a Section* to the Sym
type and an Elf64_Shdr* to the Section type.
This caused the Plan 9 compilers to complain about incompatible
type signatures in the many files that reference the Sym type.
R=rsc, dave
CC=golang-dev
https://golang.org/cl/7057058
Fixes#4186.
Back in the day, before the Go 1.0 release, $GOROOT was mandatory for building from source. Fast forward to now and $GOPATH is mandatory and $GOROOT is optional, and mainly used by those who use the binary distribution in uncommon places.
For example, most novices at least know about `sudo` as they would have used it to install the binary tarball into /usr/local. It is logical they would use the `sudo` hammer to `go get` other Go packages when faced with a permission error talking about the path they just had to use `sudo` on last time.
Even if they had read the documentation and set $GOPATH, go get will not work as expected as `sudo` masks most environment variables.
llucky(~) % ~/go/bin/go env | grep GOPATH
GOPATH="/home/dfc"
lucky(~) % sudo ~/go/bin/go env | grep GOPATH
GOPATH=""
This CL therefore proposes to remove support for using `go get` to download source into $GOROOT.
This CL also proposes an error when GOPATH=$GOROOT, as this is another place where new Go users can get stuck.
Further discussion: https://groups.google.com/d/topic/golang-nuts/VIg3fjHiHRI/discussion
R=rsc, adg, minux.ma
CC=golang-dev
https://golang.org/cl/6941058
The linker split PKGDEF into (prefix, name, def) pairs,
and defines def to begin after a space following the identifier.
This is totally wrong for the following export data:
func "".FunctionName()
var SomethingCompletelyUnrelated int
The linker would parse
name=`"".FunctionName()\n\tvar`
def=`SomethingCompletelyUnrelated int`
since there is no space after FunctionName.
R=minux.ma, rsc
CC=golang-dev
https://golang.org/cl/7068051
Our source no longer needs these flags set to build cleanly using clang.
Tested with
* Ubuntu clang version 3.0-6ubuntu3 (tags/RELEASE_30/final) (based on LLVM 3.0) on i386
* clang version 3.2 (tags/RELEASE_32/final) on amd64 cross compiling all platforms
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7058053
A constant node of type uintptr with a nil literal could
happen in two cases: []int(nil)[1:] and
uintptr(unsafe.Pointer(nil)).
Fixes#4614.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7059043
There exists a test case for this condition, but it only runs on unix systems, which neatly dovetails into the code always using ':' as the list separator.
R=adg, iant
CC=golang-dev
https://golang.org/cl/7057052
There's no b in race detector.
The new flag matches the one in the go command
(go test -race math).
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/7072043
bytes.Equal is simpler to read and should also be faster because
of short-circuiting and assembly implementations.
Change generated automatically using:
gofmt -r 'bytes.Compare(a, b) == 0 -> bytes.Equal(a, b)'
gofmt -r 'bytes.Compare(a, b) != 0 -> !bytes.Equal(a, b)'
R=golang-dev, dave, adg, rsc
CC=golang-dev
https://golang.org/cl/7038051
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
More cleanup in preparation for fixing issue 4069.
This CL replaces the three nearly identical copies of the
asmb ELF code with a single asmbelf function in elf.c.
In addition to the ELF code movement, remove the elfstr
array in favor of a simpler lookup, and identify sections by
name throughout instead of computing fragile indices.
The CL also replaces the three nearly identical copies of the
genasmsym code with a single genasmsym function in lib.c.
The ARM linker still compiles and generates binaries,
but I haven't tested the binaries. They may not work.
R=ken2
CC=golang-dev
https://golang.org/cl/7062047
The Plan 9 symbol table format defines big-endian symbol values
for portability, but we want to be able to generate an ELF object file
and let the host linker link it, as part of the solution to issue 4069.
The symbol table itself, since it is loaded into memory at run time,
must be filled in by the final host linker, using relocation directives
to set the symbol values. On a little-endian machine, the linker will
only fill in little-endian values during relocation, so we are forced
to use little-endian symbol values.
To preserve most of the original portability of the symbol table
format, we make the table itself say whether it uses big- or
little-endian values. If the table begins with the magic sequence
fe ff ff ff 00 00
then the actual table begins after those six bytes and contains
little-endian symbol values. Otherwise, the table is in the original
format and contains big-endian symbol values. The magic sequence
looks like an "end of table" entry (the fifth byte is zero), so legacy
readers will see a little-endian table as an empty table.
All the gc architectures are little-endian today, so the practical
effect of this CL is to make all the generated tables little-endian,
but if a big-endian system comes along, ld will not generate
the magic sequence, and the various readers will fall back to the
original big-endian interpretation.
R=ken2
CC=golang-dev
https://golang.org/cl/7066043
A few USED(xxx) additions and a couple of deletions of variable
initialisations that go unused. One questionable correction,
mirrored in 8l/asm.c, where the result of invocation of a function
shouldn't be used.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6736054
A new environment variable GO386 is introduced to choose between
code generation targeting 387 or SSE2. No auto-detection is
performed and the setting defaults to 387 to preserve previous
behaviour.
The patch is a reorganization of CL6549052 by rsc.
Fixes#3912.
R=minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6962043
Unnamed types like structs with embedded fields can have methods.
These methods are generated on-the-fly by the compiler and
it may happen for identical types in different packages.
The linker must accept these multiple definitions.
Fixes#4590.
R=golang-dev, rsc
CC=golang-dev, remy
https://golang.org/cl/7030051
Before this CL, defining the variable worked fine, but then when
the implicit package-level init func was created, that caused a
name collision and a confusing error about the redeclaration.
Also add a test for issue 3705 (func init() needs body).
Fixes#4517.
R=ken2
CC=golang-dev
https://golang.org/cl/7008045
An error during the compilation can be more precise
than an error at link time.
For 'func init', the error happens always: you can't forward
declare an init func because the name gets mangled.
For other funcs, the error happens only with the special
(and never used by hand) -= flag, which tells 6g the
package is pure go.
The go command now passes -= for pure Go packages.
Fixes#3705.
R=ken2
CC=golang-dev
https://golang.org/cl/6996054
Ordinary variable load was assumed to be not worth saving,
but not if one of the function calls later might change
its value.
Fixes#4313.
R=ken2
CC=golang-dev
https://golang.org/cl/6997047
The patch makes the compile user an ordinary package-local
symbol for the name of embedded fields of builtin type.
This is incompatible with the fix delivered for issue 2687
(revision 3c060add43fb) but fixes it in a different way, because
the explicit symbol on the field makes the typechecker able to
find it in lookdot.
Fixes#3552.
R=lvd, rsc, daniel.morsing
CC=golang-dev
https://golang.org/cl/6866047
The typechecking code was doing an extra, unnecessary
indirection.
Fixes#4458.
R=golang-dev, daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/6998051
remove zerostack compiler experiment; will do at link time instead
««« original CL description
cmd/gc: add GOEXPERIMENT=zerostack to clear stack on function entry
This is expensive but it might be useful in cases where
people are suffering from false positives during garbage
collection and are willing to trade the CPU time for getting
rid of the false positives.
On the other hand it only eliminates false positives caused
by other function calls, not false positives caused by dead
temporaries stored in the current function call.
The 5g/6g/8g changes were pulled out of the history, from
the last time we needed to do this (to work around a goto bug).
The code in go.h, lex.c, pgen.c is new but tiny.
R=ken2
CC=golang-dev
https://golang.org/cl/6938073
»»»
R=ken2
CC=golang-dev
https://golang.org/cl/7002051
A fatal error used to happen when escassign-ing a multiple
function return to a single node. However, the situation
naturally appears when using "go f(g())" or "defer f(g())",
because g() is escassign-ed to sink.
Fixes#4529.
R=golang-dev, lvd, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6920060
The OpenBSD ld.so(1) does not currently support PT_TLS and refuses
to load ELF binaries that contain PT_TLS sections. Do not emit PT_TLS
sections - we will handle this appropriately in runtime/cgo instead.
R=golang-dev, minux.ma, iant
CC=golang-dev
https://golang.org/cl/6846064
This is expensive but it might be useful in cases where
people are suffering from false positives during garbage
collection and are willing to trade the CPU time for getting
rid of the false positives.
On the other hand it only eliminates false positives caused
by other function calls, not false positives caused by dead
temporaries stored in the current function call.
The 5g/6g/8g changes were pulled out of the history, from
the last time we needed to do this (to work around a goto bug).
The code in go.h, lex.c, pgen.c is new but tiny.
R=ken2
CC=golang-dev
https://golang.org/cl/6938073
The code:
func main() {
v := make([]int64, 10)
i := 1
_ = v[(i*4)/3]
}
crashes compiler with:
Program received signal SIGSEGV, Segmentation fault.
0x000000000043c274 in walkexpr (np=0x7fffffffc9b8, init=0x0) at src/cmd/gc/walk.c:587
587 *init = concat(*init, n->ninit);
(gdb) bt
#0 0x000000000043c274 in walkexpr (np=0x7fffffffc9b8, init=0x0) at src/cmd/gc/walk.c:587
#1 0x0000000000432d15 in copyexpr (n=0x7ffff7f69a48, t=<optimized out>, init=0x0) at src/cmd/gc/subr.c:2020
#2 0x000000000043f281 in walkdiv (init=0x0, np=0x7fffffffca70) at src/cmd/gc/walk.c:2901
#3 walkexpr (np=0x7ffff7f69760, init=0x0) at src/cmd/gc/walk.c:956
#4 0x000000000043d801 in walkexpr (np=0x7ffff7f69bc0, init=0x0) at src/cmd/gc/walk.c:988
#5 0x000000000043cc9b in walkexpr (np=0x7ffff7f69d38, init=0x0) at src/cmd/gc/walk.c:1068
#6 0x000000000043c50b in walkexpr (np=0x7ffff7f69f50, init=0x0) at src/cmd/gc/walk.c:879
#7 0x000000000043c50b in walkexpr (np=0x7ffff7f6a0c8, init=0x0) at src/cmd/gc/walk.c:879
#8 0x0000000000440a53 in walkexprlist (l=0x7ffff7f6a0c8, init=0x0) at src/cmd/gc/walk.c:357
#9 0x000000000043d0bf in walkexpr (np=0x7fffffffd318, init=0x0) at src/cmd/gc/walk.c:566
#10 0x00000000004402bf in vmkcall (fn=<optimized out>, t=0x0, init=0x0, va=0x7fffffffd368) at src/cmd/gc/walk.c:2275
#11 0x000000000044059a in mkcall (name=<optimized out>, t=0x0, init=0x0) at src/cmd/gc/walk.c:2287
#12 0x000000000042862b in callinstr (np=0x7fffffffd4c8, init=0x7fffffffd568, wr=0, skip=<optimized out>) at src/cmd/gc/racewalk.c:478
#13 0x00000000004288b7 in racewalknode (np=0x7ffff7f68108, init=0x7fffffffd568, wr=0, skip=0) at src/cmd/gc/racewalk.c:287
#14 0x0000000000428781 in racewalknode (np=0x7ffff7f65840, init=0x7fffffffd568, wr=0, skip=0) at src/cmd/gc/racewalk.c:302
#15 0x0000000000428abd in racewalklist (l=0x7ffff7f65840, init=0x0) at src/cmd/gc/racewalk.c:97
#16 0x0000000000428d0b in racewalk (fn=0x7ffff7f5f010) at src/cmd/gc/racewalk.c:63
#17 0x0000000000402b9c in compile (fn=0x7ffff7f5f010) at src/cmd/6g/../gc/pgen.c:67
#18 0x0000000000419f86 in funccompile (n=0x7ffff7f5f010, isclosure=0) at src/cmd/gc/dcl.c:1414
#19 0x0000000000424161 in p9main (argc=<optimized out>, argv=<optimized out>) at src/cmd/gc/lex.c:431
#20 0x0000000000401739 in main (argc=<optimized out>, argv=<optimized out>) at src/lib9/main.c:35
The problem is nil init passed to mkcall().
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6940045
Ignore signals during "go run" and wait for running child
process to exit. Stop executing further tests during "go test",
wait for running tests to exit and report error exit code.
Original CL 6351053 by dfc.
Fixes#3572.
Fixes#3581.
R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/6903061
5g: Prog went from 128 bytes to 88 bytes
6g: Prog went from 174 bytes to 144 bytes
8g: Prog went from 124 bytes to 92 bytes
There may be a little more that can be squeezed out of Addr, but alignment will be a factor.
All: remove the unused pun field from Addr
R=rsc, minux.ma
CC=golang-dev
https://golang.org/cl/6922048
Change suggested by iant. The compiler generates
special code for a/b when a is -0x80...0 and b = -1.
A single instruction can cover the case where b is -1,
so only one comparison is needed.
Fixes#3551.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6922049
The code inside the casee and casep labels can perfectly be merged since
they essentially do the same. The character to be stored where cp points is
just the character contained by the c variable.
R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/6845112
This check for BADWIDTH might happen while in defercheckwidth, making it raise errors for non-erroneous situations.
Fixes#4495.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6927043
Fixes#4492.
% go version
go version devel +6b602ab487d6 Sat Dec 08 14:43:00 2012 +0100 linux/amd64
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6906058
The fixjmp step eliminates redundant chains of JMP
instructions that are produced by the compiler during
code generation.
It is already implemented in gc, and can be adapted to 6c/8c with
the exception that JMPs refer to destination by pc instead of by
pointer. The algorithm is modified to operate on Regs instead of Progs
for this reason. The pcs are already restored later by regopt.
R=goalng-dev, rsc
CC=golang-dev
https://golang.org/cl/6865046
Add missing file that should have been included in CL 6854063 / 5eac1a2d6fc3
R=remyoudompheng, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6891049
The 0-length part is fine, but some callers that write 0 bytes
also pass nil as the data pointer, and the Plan 9 kernel kills the
process with 'invalid address in sys call' in that case.
R=ken2
CC=golang-dev
https://golang.org/cl/6862051
Used to say:
issue4251.go:12: inverted slice range
issue4251.go:12: constant -1 overflows uint64
issue4251.go:16: inverted slice range
issue4251.go:16: constant -1 overflows uint64
issue4251.go:20: inverted slice range
issue4251.go:20: constant -1 overflows uint64
With this patch, only gives the "inverted slice range" errors.
R=golang-dev, daniel.morsing
CC=golang-dev
https://golang.org/cl/6871058
Fixes#4396.
For fixed arrays larger than the unmapped page, agenr would general a nil check by loading the first word of the array. However there is no requirement for the first element of a byte array to be word aligned, so this check causes a trap on ARMv5 hardware (ARMv6 since relaxed that restriction, but it probably still comes at a cost).
Switching the check to MOVB ensures alignment is not an issue. This check is only invoked in a few places in the code where large fixed arrays are embedded into structs, compress/lzw is the biggest offender, and switching to MOVB has no observable performance penalty.
Thanks to Rémy and Daniel Morsing for helping me debug this on IRC last night.
R=remyoudompheng, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6854063
The debian/kFreeBSD project uses the FreeBSD kernel and the debian userspace. From our point of view, this is freebsd not linux as GOOS talks about the kernel syscall interface, not the userspace (although cgo alters that). As debian/kFreeBSD is experimental at this time, I do not think it is worth the effort of duplicating all the freebsd specific code so this is proposal represents a reasonable workaround.
Currently cgo is not supported, make.bash will detect this and disable cgo automatically during the build.
dfc@debian:~/go/src$ uname -a
GNU/kFreeBSD debian 8.1-1-686 #0 Sat Jul 21 17:02:04 UTC 2012 i686 i386 Intel(R) Core(TM) i5-2415M CPU @ 2.30GHz GNU/kFreeBSD
dfc@debian:~/go/src$ ../bin/go version
go version devel +d05272f402ec Sat Dec 01 15:15:14 2012 -0800
Tested with GOOS=freebsd GOARCH=386
R=golang-dev
CC=golang-dev
https://golang.org/cl/6868046
The compiler was confused when inlining a T.Method(f()) call
where f returns multiple values: support for this was marked
as TODO.
Variadic calls are not supported but are not inlined either.
Add a test preventively for that case.
Fixes#4167.
R=golang-dev, rsc, lvd
CC=golang-dev
https://golang.org/cl/6871043
`godoc net/http` used to complain "/target contains more than one package: http, main"
R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/6852100
W/o this change stack traces do not show from where sync.Once()
or atomic.XXX was called.
This change add funcenter/exit instrumentation to sync/sync.atomic
packages.
R=golang-dev
CC=golang-dev
https://golang.org/cl/6854112
Package format is a utility package that takes care of
parsing, sorting of imports, and formatting of .go source
using the canonical gofmt formatting parameters.
Use go/format in various clients instead of the lower-level components.
R=r, bradfitz, dave, rogpeppe, rsc
CC=golang-dev
https://golang.org/cl/6852075
This allows 5g and 8g to benefit from the rewrite as shifts
or magic multiplies. The 64-bit arithmetic is not handled there,
and left in 6g.
Update #2230.
R=golang-dev, dave, mtj, iant, rsc
CC=golang-dev
https://golang.org/cl/6819123
Bools from comparisons can be assigned to all bool types, but this idealness would propagate through logical operators when the result should have been lowered to a non-ideal form.
Fixes#3924.
R=golang-dev, remyoudompheng, r, rsc, mtj
CC=golang-dev
https://golang.org/cl/6855061
The stack overflow checker in the linker uses the spadj field
to determine whether stack space will be large enough or not.
When spadj=0, the checker treats the function as a nosplit
and emits an error although the program is correct.
Also enable the stack checker in 8l.
Fixes#4316.
R=rsc, golang-dev
CC=golang-dev
https://golang.org/cl/6855088
The 8l linker automatically inserts XCHG instructions
to support otherwise impossible byte registers
(only available on AX, BX, CX, DX).
Sometimes AX or DX is needed (for MUL and DIV) so
we need to avoid clobbering them.
R=golang-dev, dave, iant, iant, rsc
CC=golang-dev
https://golang.org/cl/6846057
This CL starts to introduce IPv6 scoped addressing capability
into the net package.
The Public API changes are:
+pkg net, type IPAddr struct, Zone string
+pkg net, type IPNet struct, Zone string
+pkg net, type TCPAddr struct, Zone string
+pkg net, type UDPAddr struct, Zone string
Update #4234.
R=rsc, bradfitz, iant
CC=golang-dev
https://golang.org/cl/6849045
Check the return value from malloc - do not assume that we were
allocated memory just because we asked for it.
Update #4415.
R=minux.ma, daniel.morsing, remyoudompheng, rsc
CC=golang-dev
https://golang.org/cl/6782100
Saves 5 seconds on my machine. If Issue 4380 is fixed this
clone can be removed.
Update #4380
R=golang-dev, remyoudompheng, minux.ma, gri
CC=golang-dev
https://golang.org/cl/6845058
In order to add these, we need to be able to find references
to such types that already exist in the binary. To do that, introduce
a new linker section holding a list of the types corresponding to
arrays, chans, maps, and slices.
To offset the storage cost of this list, and to simplify the code,
remove the interface{} header from the representation of a
runtime type. It was used in early versions of the code but was
made obsolete by the kind field: a switch on kind is more efficient
than a type switch.
In the godoc binary, removing the interface{} header cuts two
words from each of about 10,000 types. Adding back the list of pointers
to array, chan, map, and slice types reintroduces one word for
each of about 500 types. On a 64-bit machine, then, this CL *removes*
a net 156 kB of read-only data from the binary.
This CL does not include the needed support for precise garbage
collection. I have created issue 4375 to track that.
This CL also does not set the 'algorithm' - specifically the equality
and copy functions - for a new array correctly, so I have unexported
ArrayOf for now. That is also part of issue 4375.
Fixes#2339.
R=r, remyoudompheng, mirtchovski, iant
CC=golang-dev
https://golang.org/cl/6572043
This patch introduces a sort of pre-regopt peephole optimization.
When a temporary is introduced that just holds a value for the
duration of the next instruction and is otherwise unused, we
elide it to make the job of regopt easier.
Since x86 has very few registers, this situation happens very
often. The result is large savings in stack variables for
arithmetic-heavy functions.
crypto/aes
benchmark old ns/op new ns/op delta
BenchmarkEncrypt 1301 392 -69.87%
BenchmarkDecrypt 1309 368 -71.89%
BenchmarkExpand 2913 1036 -64.44%
benchmark old MB/s new MB/s speedup
BenchmarkEncrypt 12.29 40.74 3.31x
BenchmarkDecrypt 12.21 43.37 3.55x
crypto/md5
benchmark old ns/op new ns/op delta
BenchmarkHash8Bytes 1761 914 -48.10%
BenchmarkHash1K 16912 5570 -67.06%
BenchmarkHash8K 123895 38286 -69.10%
benchmark old MB/s new MB/s speedup
BenchmarkHash8Bytes 4.54 8.75 1.93x
BenchmarkHash1K 60.55 183.83 3.04x
BenchmarkHash8K 66.12 213.97 3.24x
bench/go1
benchmark old ns/op new ns/op delta
BenchmarkBinaryTree17 8364835000 8303154000 -0.74%
BenchmarkFannkuch11 7511723000 6381729000 -15.04%
BenchmarkGobDecode 27764090 27103270 -2.38%
BenchmarkGobEncode 11240880 11184370 -0.50%
BenchmarkGzip 1470224000 856668400 -41.73%
BenchmarkGunzip 240660800 201697300 -16.19%
BenchmarkJSONEncode 155225800 185571900 +19.55%
BenchmarkJSONDecode 243347900 282123000 +15.93%
BenchmarkMandelbrot200 12240970 12201880 -0.32%
BenchmarkParse 8837445 8765210 -0.82%
BenchmarkRevcomp 2556310000 1868566000 -26.90%
BenchmarkTemplate 389298000 379792000 -2.44%
benchmark old MB/s new MB/s speedup
BenchmarkGobDecode 27.64 28.32 1.02x
BenchmarkGobEncode 68.28 68.63 1.01x
BenchmarkGzip 13.20 22.65 1.72x
BenchmarkGunzip 80.63 96.21 1.19x
BenchmarkJSONEncode 12.50 10.46 0.84x
BenchmarkJSONDecode 7.97 6.88 0.86x
BenchmarkParse 6.55 6.61 1.01x
BenchmarkRevcomp 99.43 136.02 1.37x
BenchmarkTemplate 4.98 5.11 1.03x
Fixes#4035.
R=golang-dev, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6828056
The patch adds more cases to agenr to allocate registers later,
and makes 6g generate addresses for sgen in something else than
SI and DI. It avoids a complex save/restore sequence that
amounts to allocate a register before descending in subtrees.
Fixes#4207.
R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/6817080
xtramodes' C_PBIT optimisation transforms:
MOVW 0(R3),R1
ADD $4,R3,R3
into:
MOVW.P 4(R3),R1
and the AADD optimisation tranforms:
ADD R0,R1
MOVBU 0(R1),R0
into:
MOVBU R0<<0(R1),R0
5g does not appear to generate sequences that
can be transformed by xtramodes' AMOVW.
R=remyoudompheng, rsc
CC=golang-dev
https://golang.org/cl/6817085
On ARM, char is unsigned, and the code generation for
multiplication gets totally broken.
Fixes#4354.
R=golang-dev, dave, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6826079
Currently it works incorrectly if user specifies own build tags
and with race detection (e.g. runtime/race is not selected,
because it contains only test files with +build race).
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6814107
When exporting a body containing
x, ok := v.(Type)
the definition for Type was not being included, so when the body
was actually used, it would cause an "unknown type" compiler error.
Fixes#4370.
R=ken2
CC=golang-dev
https://golang.org/cl/6827064
This is blocking me submitting the net fd timeout
CL, since goapi chokes on my constant.
The much more extensive fix to goapi's type checker
in pending review in https://golang.org/cl/6742050
But I'd rather get this quick fix in first.
R=golang-dev, mikioh.mikioh
CC=golang-dev
https://golang.org/cl/6818104
The code assumed that the only choices were EscNone, EscScope, and EscHeap,
so that it makes sense to set EscScope only if the current setting is EscNone.
Now that we have the many variants of EscReturn, this logic is false, and it was
causing important EscScopes to be ignored in favor of EscReturn.
Fixes#4360.
R=ken2
CC=golang-dev, lvd
https://golang.org/cl/6816103
Avoids problems with local declarations shadowing other names.
We write a more explicit form than the incoming program, so there
may be additional type annotations. For example:
int := "hello"
j := 2
would normally turn into
var int string = "hello"
var j int = 2
but the int variable shadows the int type in the second line.
This CL marks all local variables with a per-function sequence number,
so that this would instead be:
var int·1 string = "hello"
var j·2 int = 2
Fixes#4326.
R=ken2
CC=golang-dev
https://golang.org/cl/6816100
Current racewalk transformation looks like:
x := <-makeChan().c
\/\/\/\/\/\/\/\/\/
runtime.raceread(&makeChan().c)
x := <-makeChan().c
and so makeChan() is called twice.
With this CL the transformation looks like:
x := <-makeChan().c
\/\/\/\/\/\/\/\/\/
chan *tmp = &(makeChan().c)
raceread(&*tmp)
x := <-(*tmp)
Fixes#4245.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6822075
It is refactoring towards generic walk
+ it handles mode nodes.
Partially fixes 4228 issue.
R=golang-dev, lvd, rsc
CC=golang-dev
https://golang.org/cl/6775098
Unlike when using -http, godoc -url didn't initialize the "filesystem"
and metadata that are used when generating responses. This CL adds this
initialization, so that -url provides the same results as an HTTP
request when using -http.
Fixes#4335.
R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/6817075
When the first result of a type assertion is blank, the compiler would still copy out a potentially large non-interface type.
Fixes#1021.
R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/6812079
The test for this is test/index.go, which is not run by
default. That test does not currently pass even after this is
applied, due to issue 4348.
Fixes#4344.
R=golang-dev, daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/6815085
Currently the build fails with -race if a package in GOPATH
imports another package in GOPATH.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/6811083
This CL is a backport of 6012049 which improves code
generation for shift operations.
benchmark old ns/op new ns/op delta
BenchmarkLSL 9 5 -49.67%
BenchmarkLSR 9 4 -50.00%
R=golang-dev, minux.ma, r, rsc
CC=golang-dev
https://golang.org/cl/6813045
It happens that blocks are used for function calls in a
quite low-level way so they cannot be instrumented as
usual.
Blocks are also used for inlined functions.
R=golang-dev, rsc, dvyukov
CC=golang-dev
https://golang.org/cl/6821068
Compiling expressions like:
s[s[s[s[s[s[s[s[s[s[s[s[i]]]]]]]]]]]]
make 5g and 6g run out of registers. Such expressions can arise
if a slice is used to represent a permutation and the user wants
to iterate it.
This is due to the usual problem of allocating registers before
going down the expression tree, instead of allocating them in a
postfix way.
The functions cgenr and agenr (that generate a value to a newly
allocated register instead of an existing location), are either
introduced or modified when they already existed to allocate
the new register as late as possible, and sudoaddable is disabled
for OINDEX nodes so that igen/agenr is used instead.
Update #4207.
R=dave, daniel.morsing, rsc
CC=golang-dev
https://golang.org/cl/6733055
This is an experiment in static analysis of Go programs
to understand which struct fields a program might use.
It is not part of the Go language specification, it must
be enabled explicitly when building the toolchain,
and it may be removed at any time.
After building the toolchain with GOEXPERIMENT=fieldtrack,
a specific field can be marked for tracking by including
`go:"track"` in the field tag:
package pkg
type T struct {
F int `go:"track"`
G int // untracked
}
To simplify usage, only named struct types can have
tracked fields, and only exported fields can be tracked.
The implementation works by making each function begin
with a sequence of no-op USEFIELD instructions declaring
which tracked fields are accessed by a specific function.
After the linker's dead code elimination removes unused
functions, the fields referred to by the remaining
USEFIELD instructions are the ones reported as used by
the binary.
The -k option to the linker specifies the fully qualified
symbol name (such as my/pkg.list) of a string variable that
should be initialized with the field tracking information
for the program. The field tracking string is a sequence
of lines, each terminated by a \n and describing a single
tracked field referred to by the program. Each line is made
up of one or more tab-separated fields. The first field is
the name of the tracked field, fully qualified, as in
"my/pkg.T.F". Subsequent fields give a shortest path of
reverse references from that field to a global variable or
function, corresponding to one way in which the program
might reach that field.
A common source of false positives in field tracking is
types with large method sets, because a reference to the
type descriptor carries with it references to all methods.
To address this problem, the CL also introduces a comment
annotation
//go:nointerface
that marks an upcoming method declaration as unavailable
for use in satisfying interfaces, both statically and
dynamically. Such a method is also invisible to package
reflect.
Again, all of this is disabled by default. It only turns on
if you have GOEXPERIMENT=fieldtrack set during make.bash.
R=iant, ken
CC=golang-dev
https://golang.org/cl/6749064
1. Prepend racefuncenter() to fn->enter -- fn->enter can contain new() calls,
and we want them to be in the scope of the function.
2. Dump fn->enter and fn->exit.
3. Add TODO that OTYPESW expression can contain interesting memory accesses.
4. Ignore only _ names instead of all names starting with _.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6822048
Use wrapper functions to tell scheduler what we are doing.
With this patch, and a separate patch to the go tool, all the
cgo tests pass with gccgo.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6812058
* Use -fgo-pkgpath and -gccgopkgpath rather than -fgo-prefix
and -gccgoprefix.
* Define GOPKGPATH when compiling .c or .s files for gccgo.
* Use -fgo-relative-import-path.
* Produce .o files for gccgo, not .[568] files.
* Pass -E when linking if using cgo.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6820064
The idea is to (1) process ninit of all nodes,
and (2) put instrumentation of ninit into the nodes themselves (not the top-level statement ninit).
Fixes#4304.
R=golang-dev, rsc
CC=golang-dev, lvd
https://golang.org/cl/6818049
When local declarations needed unexported types, these could
be missing in the export data.
Fixes build with -gcflags -lll, except for exp/gotype.
R=golang-dev, rsc, lvd
CC=golang-dev
https://golang.org/cl/6813067
This should make the compiler emit errors specific to the bounds checking instead of overflow errors on the underlying types.
Updates #4232.
R=rsc
CC=golang-dev
https://golang.org/cl/6783054
Plan 9 and Go's lib9/fmt disagree on whether %#x includes the 0x prefix
when printing 0, because ANSI C gave bad advice long ago.
Avoiding that case makes binaries compiled on different systems compatible.
R=ken2
CC=akumar, golang-dev
https://golang.org/cl/6814066
compiler_rt introduces a weak and hidden symbol compilerrt_abort_impl
into our pre-linked _all.o object, we have to handle it.
Fixes#4273.
R=iant, rsc, r
CC=golang-dev
https://golang.org/cl/6783050
Feature extraction was tested before, but not the final diffs.
This CL breaks function main into a smaller main + testable
compareAPI.
No functional changes.
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/6820057
- make sure dclcontext == PAUTO only in function bodies
- introduce PDISCARD to discard declarations in bodies of repeated imports
- skip printing initializing OAS'es in export mode, assuming they only occur after ODCL's
- remove ODCL and the initializing OAS from inl.c:ishairy
- fix confused use of ->typecheck in typecheckinl: it's about the ->inl, not about the fn.
- debuging aids: print ntype on ONAMEs too and -Emm instead of -Ell.
fixes#2812
R=rsc
CC=golang-dev
https://golang.org/cl/6800043
includes step 0: synthesize outparams, from 6600044
includes step 1,2: give outparams loopdepth 0 and verify unchanged results
generate esc:$mask tags, but still tie to sink if a param has mask != 0
from 6610054
adds final steps:
- have esccall generate n->escretval, a list of nodes the function results flow to
- use these in esccall and ORETURN/OAS2FUNC/and f(g())
- only tie parameters to sink if tag is absent, otherwise according to mask, tie them to escretval
R=rsc, bradfitz
CC=dave, gobot, golang-dev, iant, rsc
https://golang.org/cl/6741044
includes step 0: synthesize outparams, from 6600044
step 1: give outparams loopdepth 0 and verify unchanged results
step 2: generate esc:$mask tags, but still tie to sink if a param has mask != 0
next step: use in esccall (and ORETURN with implicit OAS2FUNC) to avoid tying to sink
R=rsc
CC=golang-dev
https://golang.org/cl/6610054
in typecheck and walk, conversion from OAS2RECV to OAS2
and to OSELRECV2 duplicated the ->rlist->n to ->right
thereby destroying the strict tree-ness of the AST (up to
ONAMES) of course. Several recursions in esc.c and inl.c
and probably elsewhere assume nodes of the tree aren't duplicated.
rather than defensively code around this, i'd rather assert
these cases away and fix their cause.
(this was tripped in 6741044)
R=rsc
CC=golang-dev
https://golang.org/cl/6750043
It's common to use the go list command in shell scripts, but
currently it's awkward to print a string slice from the Package
type in a way that's easily parseable by the shell. For example:
go list -f '{{range .Deps}}{{.}}
{{end}}'
(and even that prints an unwanted new line at the end|).
To make this easier, this CL adds a "join" function to the
format template.
go list -f '{{join .Deps "\n"}}'
R=rsc, dsymonds, minux.ma, remyoudompheng, r
CC=golang-dev
https://golang.org/cl/6680044
Someone new to the language may not know the connection between ints and arrays, which was the only thing that the previous error told you anything about.
Fixes#4256.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6739048
Since this patch changes the way complex literals are written
in export data, there are a few other glitches.
Fixes#4159.
R=golang-dev, rsc
CC=golang-dev, remy
https://golang.org/cl/6674047
This patch is enough to fix compilation of
exp/types tests but only passes a stripped down
version of the appripriate torture test.
Update #4207.
R=dave, nigeltao, rsc, golang-dev
CC=golang-dev
https://golang.org/cl/6621061
Valgrind Massif result when linking godoc:
On amd64:
old new -/+
mem_heap_B 185844612 175358047 -5.7%
mem_heap_extra_B 773404 773137 -0.0%
On 386/ARM:
old new -/+
mem_heap_B 141775701 131289941 -7.4%
mem_heap_extra_B 737011 736955 -0.0%
R=golang-dev, r, dave
CC=golang-dev
https://golang.org/cl/6655045
The compiler is crashing on the following code:
type TypeID int
func (t *TypeID) encodeType(x int) (tt TypeID, err error) {
switch x {
case 0:
return t.encodeType(x * x)
}
return 0, nil
}
The pass marks "return struct" {tt TypeID, err error} as used,
and this causes internal check failure.
I've added the test to:
https://golang.org/cl/6525052/diff/7020/src/pkg/runtime/race/regression_test.go
R=golang-dev, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/6611049
Preparation for forthcoming CL 6624051: Will make it
easier to see if/what changes are incurred by it.
The alignment changes in this CL are due to CL 6610051
(fix to alignment heuristic) where it appears that an
old version of gofmt was run (and thus the correct
alignment updates were not done).
R=r
CC=golang-dev
https://golang.org/cl/6639044
1. correctly initialize .plt.got entries (point to the 1st entry)
2. add section .rel.plt (FreeBSD insists PLT relocs to be there)
3. put relocs of .got.plt into .rel.plt
4. set ELFOSABI_FREEBSD in ELF header
R=rsc
CC=golang-dev
https://golang.org/cl/6643050
Check for specific, important misalignment in garbage collector.
Not a complete fix for issue 599 but an important workaround.
Update #599.
R=golang-dev, iant, dvyukov
CC=golang-dev
https://golang.org/cl/6641049
Updates setup-godoc-app.bash to produce a working godoc app
by substituting the go1.0.x go/... packages with those from tip.
R=gri
CC=golang-dev
https://golang.org/cl/6587080
1. R_ARM_CALL can also be used to call a PLT entry
2. add support for R_ARM_PC24 and R_ARM_JUMP24
3. refactor, remove D_PLT32 in favor of D_CALL
Fixes#4006.
R=rsc, dave
CC=fullung, golang-dev
https://golang.org/cl/6622057
The protection against segfaults does not completely solve
crashes and breaks test/fixedbugs/bug365.go
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6615058
The nil dereference in the next few lines doesn't seem
to cause a segmentation fault on Unix, but does seem
to halt the Go compiler.
The following is a test case:
>>>
package main
func mine(int b) int {
return b + 2
}
func main() {
mine()
c = mine()
}
<<<
Without this change only the following is caught:
typecheck.go:3: undefined: b
typecheck.go:4: undefined: b
with it, we catch all the errors:
typecheck.go:3: undefined: b
typecheck.go:4: undefined: b
typecheck.go:10: undefined: c
typecheck.go:10: cannot assign to c .
R=rsc, minux.ma
CC=golang-dev
https://golang.org/cl/6542060
The profiler collects goroutine blocking information similar to Google Perf Tools.
You may see an example of the profile (converted to svg) attached to
http://code.google.com/p/go/issues/detail?id=3946
The public API changes are:
+pkg runtime, func BlockProfile([]BlockProfileRecord) (int, bool)
+pkg runtime, func SetBlockProfileRate(int)
+pkg runtime, method (*BlockProfileRecord) Stack() []uintptr
+pkg runtime, type BlockProfileRecord struct
+pkg runtime, type BlockProfileRecord struct, Count int64
+pkg runtime, type BlockProfileRecord struct, Cycles int64
+pkg runtime, type BlockProfileRecord struct, embedded StackRecord
R=rsc, dave, minux.ma, r
CC=gobot, golang-dev, r, remyoudompheng
https://golang.org/cl/6443115