Ignore symbols that aren't text, data, or bss since they cause
problems when dissassembling instructions with small immediate
values.
Before:
build.go:142 0x10ee 83ec50 SUBL $text/template/parse.autotmp_1293(SB), SP
After:
build.go:142 0x10ee 83ec50 SUBL $0x50, SP
Fixes#7947.
LGTM=rsc
R=rsc, 0intro
CC=golang-codereviews
https://golang.org/cl/93520045
Passes the expanded test in CL 100660044,
which gives me some confidence that it
might be right.
(The old code failed by not considering all the
low bits.)
LGTM=r
R=golang-codereviews, r, bradfitz
CC=golang-codereviews, iant, khr
https://golang.org/cl/99410051
This idea was rejected in CL 5731059. We should fix the
runtime docs instead.
««« original CL description
cmd/dist: reflect local changes to tree in goversion
runtime.Version() requires a trailing "+" when
tree had local modifications at time of build.
Fixes#7701
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/84040045
»»»
LGTM=rsc, mra
R=iant, rsc, mra
CC=golang-codereviews
https://golang.org/cl/100520043
Explain which files the go command looks at, and what they represent.
Fixes#6348.
LGTM=rsc
R=rsc, minux.ma
CC=golang-codereviews
https://golang.org/cl/96480043
Add nacl.bash, the NaCl version of all.bash.
It's a separate script because it builds a variant of package syscall
with a large zip file embedded in it, containing all the input files
needed for tests.
Disable various tests new since the last round, mostly the ones using os/exec.
Fixes#7945.
LGTM=dave
R=golang-codereviews, remyoudompheng, dave, bradfitz
CC=golang-codereviews
https://golang.org/cl/100590044
The float32 const conversion used to round to float64
and then use the hardware to round to float32.
Even though there was a range check before this
conversion, the double rounding introduced inaccuracy:
the round to float64 might round the value further away
from the float32 range, reaching a float64 value that
could not actually be rounded to float32. The hardware
appears to give us 0 in that case, but it is probably undefined.
Double rounding also meant that the wrong value might
be used for certain border cases.
Do the rounding the float32 ourselves, just as we already
did the rounding to float64. This makes the conversion
precise and also makes the conversion match the range check.
Finally, add some code to print very large (bigger than float64)
floating point constants in decimal floating point notation instead
of falling back to the precise but human-unreadable binary floating
point notation.
Fixes#8015.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews, r
https://golang.org/cl/100580044
Update #7980
This CL make the linker abort for the example program. For Go 1.4,
we need to find a general way to handle large memory model programs.
LGTM=dave, josharian, iant
R=iant, dave, josharian
CC=golang-codereviews
https://golang.org/cl/91500046
The temporary-introducing pass was not recursing
into the argumnt of a receive operation.
Fixes#8011.
LGTM=r
R=golang-codereviews, r
CC=golang-codereviews, iant, khr
https://golang.org/cl/91540043
TestLargeDefs was issuing over one million small writes to
create a 7MB file (large.go). This is quite slow on Plan 9
since our disk file systems aren't very fast and they're
usually accessed over the network.
Buffering the writes makes the test about six times faster.
Even on Linux, it's about 1.5 times faster.
Here are the results on a slow Plan 9 machine:
Before:
% ./pack.test -test.v -test.run TestLargeDefs
=== RUN TestLargeDefs
--- PASS: TestLargeDefs (125.11 seconds)
PASS
After:
% ./pack.test -test.v -test.run TestLargeDefs
=== RUN TestLargeDefs
--- PASS: TestLargeDefs (20.835 seconds)
PASS
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/95040044
The introduction of temporaries in order.c was not
quite right for two corner cases:
1) The rewrite that pushed new variables on the lhs of
a receive into the body of the case was dropping the
declaration of the variables. If the variables escape,
the declaration is what allocates them.
Caught by escape analysis sanity check.
In fact the declarations should move into the body
always, so that we only allocate if the corresponding
case is selected. Do that. (This is an optimization that
was already present in Go 1.2. The new order code just
made it stop working.)
Fixes#7997.
2) The optimization to turn a single-recv select into
an ordinary receive assumed it could take the address
of the destination; not so if the destination is _.
Fixes#7998.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/100480043
The GC program describing a data structure sometimes trusts the
pointer base type and other times does not (if not, the garbage collector
must fall back on per-allocation type information stored in the heap).
Make the scanning of a pointer in an interface do the same.
This fixes a crash in a particular use of reflect.SliceHeader.
Fixes#8004.
LGTM=khr
R=golang-codereviews, khr
CC=0xe2.0x9a.0x9b, golang-codereviews, iant, r
https://golang.org/cl/100470045
Globals, function arguments, and results are special cases in
registerization.
Globals must be flushed aggressively, because nearly any
operation can cause a panic, and the recovery code must see
the latest values. Globals also must be loaded aggressively,
because nearly any store through a pointer might be updating a
global: the compiler cannot see all the "address of"
operations on globals, especially exported globals. To
accomplish this, mark all globals as having their address
taken, which effectively disables registerization.
If a function contains a defer statement, the function results
must be flushed aggressively, because nearly any operation can
cause a panic, and the deferred code may call recover, causing
the original function to return the current values of its
function results. To accomplish this, mark all function
results as having their address taken if the function contains
any defer statements. This causes not just aggressive flushing
but also aggressive loading. The aggressive loading is
overkill but the best we can do in the current code.
Function arguments must be considered live at all safe points
in a function, because garbage collection always preserves
them: they must be up-to-date in order to be preserved
correctly. Accomplish this by marking them live at all call
sites. An earlier attempt at this marked function arguments as
having their address taken, which disabled registerization
completely, making programs slower. This CL's solution allows
registerization while preserving safety. The benchmark speedup
is caused by being able to registerize again (the earlier CL
lost the same amount).
benchmark old ns/op new ns/op delta
BenchmarkEqualPort32 61.4 56.0 -8.79%
benchmark old MB/s new MB/s speedup
BenchmarkEqualPort32 521.56 570.97 1.09x
Fixes#1304. (again)
Fixes#7944. (again)
Fixes#7984.
Fixes#7995.
LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews, iant, r
https://golang.org/cl/97500044
Turns out elf.File.Sections is indexed by the actual
section number, not the number minus one.
I don't know why I thought the -1 was necessary.
Fixes objdump test (and therefore build) on ELF systems.
While we're here, fix bounds on gnuDump so that we
don't crash when asked to disassemble outside
the text segment. May fix Windows build or at least
make the failure more interesting.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/92390043
There is some duplication here with cmd/nm.
There is a TODO to address that after 1.3 is out.
Update #7452
x86 disassembly works and is tested.
The arm disassembler does not exist yet
and is therefore not yet hooked up.
LGTM=crawshaw, iant
R=crawshaw, iant
CC=golang-codereviews
https://golang.org/cl/91360046
AddressSanitizer says:
AddressSanitizer: heap-buffer-overflow on address 0x60200001b6f3
READ of size 6 at 0x60200001b6f3 thread T0
#0 0x46741b in __interceptor_memcmp asan_interceptors.cc:337
#1 0x4b5794 in compile src/cmd/6g/../gc/pgen.c:177
#2 0x509b81 in funccompile src/cmd/gc/dcl.c:1457
#3 0x520fe2 in p9main src/cmd/gc/lex.c:489
#4 0x5e2e01 in main src/lib9/main.c:57
#5 0x7fab81f7976c in __libc_start_main /build/buildd/eglibc-2.15/csu/libc-start.c:226
#6 0x4b16dc in _start (pkg/tool/linux_amd64/6g+0x4b16dc)
0x60200001b6f3 is located 0 bytes to the right of 3-byte region [0x60200001b6f0,0x60200001b6f3)
allocated by thread T0 here:
#0 0x493ec8 in __interceptor_malloc asan_malloc_linux.cc:75
#1 0x54d64e in mal src/cmd/gc/subr.c:459
#2 0x5260d5 in yylex src/cmd/gc/lex.c:1605
#3 0x52078f in p9main src/cmd/gc/lex.c:402
#4 0x5e2e01 in main src/lib9/main.c:57
If the memory block happens to be at the end of hunk and page bounadry,
this out-of-bounds can lead to a crash.
LGTM=dave, iant
R=golang-codereviews, dave, iant
CC=golang-codereviews
https://golang.org/cl/93370043
The inputs to a function are marked live at all times in the
liveness bitmaps, so that the garbage collector will not free
the things they point at and reuse the pointers, so that the
pointers shown in stack traces are guaranteed not to have
been recycled.
Unfortunately, no one told the register optimizer that the
inputs need to be preserved at all call sites. If a function
is done with a particular input value, the optimizer will stop
preserving it across calls. For single-word values this just
means that the value recorded might be stale. For multi-word
values like slices, the value recorded could be only partially stale:
it can happen that, say, the cap was updated but not the len,
or that the len was updated but not the base pointer.
Either of these possibilities (and others) would make the
garbage collector misinterpret memory, leading to memory
corruption.
This came up in a real program, in which the garbage collector's
'slice len ≤ slice cap' check caught the inconsistency.
Fixes#7944.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews, khr
https://golang.org/cl/100370045
This is joint work with Daniel Morsing.
In order for the register allocator to alias two variables, they must have the same width, stack offset, and etype. Code generation was altering a variable's etype in a few places. This prevented the variable from being moved to a register, which in turn prevented peephole optimization. This failure to alias was very common, with almost 23,000 instances just running make.bash.
This phenomenon was not visible in the register allocation debug output because the variables that failed to alias had the same name. The debugging-only change to bits.c fixes this by printing the variable number with its name.
This CL fixes the source of all etype mismatches for 6g, all but one case for 8g, and depressingly few cases for 5g. (I believe that extending CL 6819083 to 5g is a prerequisite.) Fixing the remaining cases in 8g and 5g is work for the future.
The etype mismatch fixes are:
* [gc] Slicing changed the type of the base pointer into a uintptr in order to perform arithmetic on it. Instead, support addition directly on pointers.
* [*g] OSPTR was giving type uintptr to slice base pointers; undo that. This arose, for example, while compiling copy(dst, src).
* [8g] 64 bit float conversion was assigning int64 type during codegen, overwriting the existing uint64 type.
Note that some etype mismatches are appropriate, such as a struct with a single field or an array with a single element.
With these fixes, the number of registerizations that occur while running make.bash for 6g increases ~10%. Hello world binary size shrinks ~1.5%. Running all benchmarks in the standard library show performance improvements ranging from nominal to substantive (>10%); a full comparison using 6g on my laptop is available at https://gist.github.com/josharian/8f9b5beb46667c272064. The microbenchmarks must be taken with a grain of salt; see issue 7920. The few benchmarks that show real regressions are likely due to issue 7920. I manually examined the generated code for the top few regressions and none had any assembly output changes. The few benchmarks that show extraordinary improvements are likely also due to issue 7920.
Performance results from 8g appear similar to 6g.
5g shows no performance improvements. This is not surprising, given the discussion above.
Update #7316
LGTM=rsc
R=rsc, daniel.morsing, bradfitz
CC=dave, golang-codereviews
https://golang.org/cl/91850043
The runtime was detecting the cycle already,
but we can give a better error without even
building the binary.
Fixes#7789.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/96290043
This change requires using SWIG version 3.0 or later. Earlier
versions of SWIG do not generate the pragmas required to use
the external linker.
Fixes#7155.
Fixes#7156.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/97120046
Before we used line 1 of the first source file.
This should be clearer.
Fixes#4388.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/92250044
This is a trivial change to make use of an existing `nl` byte slice
containing a single '\n' character. It's already declared and
used in another place in this file, so it might as well be used
in the other location instead of
a new slice literal. There should be no change in behavior,
aside from potentially less allocations.
This is my first CL, so I wanted to use a simple, hopefully non-controversial,
minor improvement to get more comfortable with golang contribution process.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/97280043
list has been adding them one at a time haphazardly
(race and tags were there and documented; compiler
was there and undocumented).
clean -i needs -compiler in order to clean the
installed targets for alternate compilers.
Fixes#7302.
While we're here, tweak the language in the 'go get' docs
about build flags.
Fixes#7807.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/99130043
If you write:
var x = 3
then the compiler arranges for x to be initialized in the linker
with an actual 3 from the data segment, rather than putting
x in the bss and emitting init-time "x = 3" assignment code.
If you write:
var y = x
var x = 3
then the compiler is clever and treats this the same as if
the code said 'y = 3': they both end up in the data segment
with no init-time assignments.
If you write
var y = x
var x int
then the compiler was treating this the same as if the
code said 'x = 0', making both x and y zero and avoiding
any init-time assignment.
This copying optimization to avoid init-time assignment of y
is incorrect if 'var x int' doesn't mean 'x = 0' but instead means
'x is initialized in C or assembly code'. The program ends up
with 'y = 0' instead of 'y = the value specified for x in that other code'.
Disable the propagation if there is no initializer for x.
This comes up in some uses of cgo, because cgo generates
Go globals that are initialized in accompanying C files.
Fixes#7665.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/93200044
If the ... element type contained no pointers,
then the escape analysis did not track the ... itself.
This manifested in an escaping ...byte being treated
as non-escaping.
Fixes#7934.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/100310043
The register allocator decides which variables should be placed into registers by charging for each load/store and crediting for each use, and then selecting an allocation with minimal cost. NOPs will be eliminated, however, so using a variable in a NOP should not generate credit.
Issue 7867 arises from attempted registerization of multi-word variables because they are used in NOPs. By not crediting for that use, they will no longer be considered for registerization.
This fix could theoretically lead to better register allocation, but NOPs are rare relative to other instructions.
Fixes#7867.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/94810044
Where the spelling changed from British to
US norm (e.g., optimise -> optimize) it follows
the style in that file.
LGTM=adonovan
R=golang-codereviews, adonovan
CC=golang-codereviews
https://golang.org/cl/96980043
This change allows us to give an hg tag such as "go1.3beta1" to
revisions in the main branch without breaking the build.
This is helpful for community members who want to build the beta
from source.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/90190044
go test may call builder.init() multiple times which will create a new work directory. The cleanup needs to hoist the current work directory.
Fixes#7904.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/95900044
For gccgo we rename exported functions so that the compiler
will make them visible. This CL adds a #define so that C
functions that #include "cgo_export.h" can use the expected
names of the function.
The test for this is the existing issue6833 test in
misc/cgo/test. Without this CL it fails when using
-compiler=gccgo.
LGTM=minux.ma, rsc
R=golang-codereviews, gobot, rsc, minux.ma
CC=golang-codereviews
https://golang.org/cl/91830046
Previously we used strndup(3) to implement C.CString for gccgo. This
is wrong because strndup assumes the string to be null terminated,
and stops at the first null terminator. Instead, use malloc
and memmove to create a copy of the string, as we do in the
gc implementation.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/96790047
This should have been part of 36eb4a62fbb6,
but I later discovered that addresses are all wrong.
Appropriate test added now.
LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/89470043
CL 89050043 only allows -ccflags for 'go test', this
CL really handles the flag like the other -??flags.
Many thanks to Dobrosław Żybort for pointing this out.
Fixes#7810 (again).
LGTM=iant, matrixik
R=golang-codereviews, iant, matrixik
CC=golang-codereviews
https://golang.org/cl/89230044
following on CL https://golang.org/cl/76810045 and
issue 7563, i now see there's another "remove(outfile)" a few
dozen lines down that also needs fixing.
LGTM=iant
R=golang-codereviews, iant
CC=0intro, golang-codereviews, r
https://golang.org/cl/89030043
It is possible to use ./ imports on Windows but it
requires some extra command-line work
('go build' does this automatically, but we can't use 'go build' here).
Instead, use an ordinary import and -I/-L, which are easier to use.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/89040043
Variables declared with 'var' have no sym->def.
Fixes#7794.
LGTM=rsc
R=golang-codereviews, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/88360043
Before the switch to liblink, the linkers accepted the -c flag
to print the call graph. This change restores the functionality.
This came in handy when I was trying to audit the use of SSE
instructions inside the Plan 9 note handler.
LGTM=rsc
R=golang-codereviews, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/73990043
https://golang.org/cl/60590044 edited
doc.go without editing the file it is generated from.
The edit was lost at the next mkdoc.sh.
Make the change in help.go and rerun mkdoc.sh.
Pointed out in the review of CL 68580043.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/88760043
The new code is adapted from the Go 1.2 nosplit code,
but it does not have the bug reported in issue 7623:
g% go run nosplit.go
g% go1.2 run nosplit.go
BUG
rejected incorrectly:
main 0 call f; f 120
linker output:
# _/tmp/go-test-nosplit021064539
main.main: nosplit stack overflow
120 guaranteed after split check in main.main
112 on entry to main.f
-8 after main.f uses 120
g%
Fixes#6931.
Fixes#7623.
LGTM=iant
R=golang-codereviews, iant, ality
CC=golang-codereviews, r
https://golang.org/cl/88190043
The name linkwriteobj is misleading because it implies that
the function has something to do with the linker, which it
does not. The name is historical: the function performs an
operation that was previously performed by the linker, but no
longer is.
LGTM=rsc
R=rsc, minux.ma
CC=golang-codereviews
https://golang.org/cl/88210045
Without the leaf bit, the linker cannot record
the correct frame size in the symbol table, and
then stack traces get mangled. (Only for ARM.)
Fixes#7338.
Fixes#7347.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/88550043
In large functions with many variables, the register optimizer
may give up and choose not to track certain variables at all.
In this case, the "nextinnode" information linking together
all the words from a given variable will be incomplete, and
the result may be that only some of a multiword value is
preserved across a call. That confuses the garbage collector,
so don't do that. Instead, mark those variables as having
their address taken, so that they will be preserved at all
calls. It's overkill, but correct.
Tested by hand using the 6g -S output to see that it does fix
the buggy generated code leading to the issue 7726 failure.
There is no automated test because I managed to break the
compiler while writing a test (see issue 7727). I will check
in a test along with the fix to issue 7727.
Fixes#7726.
LGTM=khr
R=khr, bradfitz, dave
CC=golang-codereviews
https://golang.org/cl/85200043
linklookup uses hash(name, v) as the hash table index but then
only compares name to find a symbol to return.
If hash(name, v1) == hash(name, v2) for v1 != v2, the lookup
for v2 will return the symbol with v1.
The input routines assume that each symbol is found only once,
and then each symbol is added to a linked list, with the list header
in the symbol. Adding a symbol to such a list multiple times
short-circuits the list the second time it is added, causing symbols
to be dropped.
The liblink rewrite introduced an elegant, if inefficient, handling
of duplicated symbols by creating a dummy symbol to read the
duplicate into. The dummy symbols are named .dup with
sequential version numbers. With many .dup symbols, eventually
there will be a conflict, causing a duplicate list add, causing elided
symbols, causing a crash when calling one of the elided symbols.
The bug is old (2011) but could not have manifested until the
liblink rewrite introduced this heavily duplicated symbol .dup.
(See History section below.)
1. Correct the lookup function.
2. Since we want all the .dup symbols to be different, there's no
point in inserting them into the table. Call linknewsym directly,
avoiding the lookup function entirely.
3. Since nothing can refer to the .dup symbols, do not bother
adding them to the list of functions (textp) at all.
4. In lieu of a unit test, introduce additional consistency checks to
detect adding a symbol to a list multiple times. This would have
caught the short-circuit more directly, and it will detect a variety
of double-use bugs, including the one arising from the bad lookup.
Fixes#7749.
History
On April 9, 2011, I submitted CL 4383047, making ld 25% faster.
Much of the focus was on the hash table lookup function, and
one of the changes was to remove the s->version == v comparison [1].
I don't know if this was a simple editing error or if I reasoned that
same name but different v would yield a different hash slot and
so the name test alone sufficed. It is tempting to claim the former,
but it was probably the latter.
Because the hash is an iterated multiply+add, the version ends up
adding v*3ⁿ to the hash, where n is the length of the name.
A collision would need x*3ⁿ ≡ y*3ⁿ (mod 2²⁴ mod 100003),
or equivalently x*3ⁿ ≡ x*3ⁿ + (y-x)*3ⁿ (mod 2²⁴ mod 100003),
so collisions will actually be periodic: versions x and y collide
when d = y-x satisfies d*3ⁿ ≡ 0 (mod 2²⁴ mod 100003).
Since we allocate version numbers sequentially, this is actually
about the best case one could imagine: the collision rate is
much lower than if the hash were more random.
http://play.golang.org/p/TScD41c_hA computes the collision
period for various name lengths.
The most common symbol in the new linker is .dup, and for n=4
the period is maximized: the 100004th symbol is the first collision.
Unfortunately, there are programs with more duplicated symbols
than that.
In Go 1.2 and before, duplicate symbols were handled without
creating a dummy symbol, so this particular case for generating
many duplicate symbols could not happen. Go does not use
versioned symbols. Only C does; each input file gives a different
version to its static declarations. There just aren't enough C files
for this to come up in that context.
So the bug is old but the realization of the bug is new.
[1] https://golang.org/cl/4383047/diff/5001/src/cmd/ld/lib.c
LGTM=minux.ma, iant, dave
R=golang-codereviews, minux.ma, bradfitz, iant, dave
CC=golang-codereviews, r
https://golang.org/cl/87910047
This code never got updated after the liblink shuffle.
Tested by hand that it works and respects GOROOT_FINAL.
The discussion in issue 6963 suggests that perhaps we should
just drop runtime-gdb.py entirely, but I am not convinced
that is true. It was in Go 1.2 and I don't see a reason not to
keep it in Go 1.3. The fact that binaries have not been emitting
the reference was just a missed detail in the liblink conversion,
not part of a grand plan.
Fixes#7506.
Fixes#6963.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews, iant, r
https://golang.org/cl/87870048
If we compile a generated file stored in a temporary
directory - let's say /tmp/12345/work/x.c - then by default
6c stores the full path and then the pcln table in the
final binary includes the full path. This makes repeated builds
(using different temporary directories) produce different
binaries, even if the inputs are the same.
In the old 'go tool pack', the P flag specified a prefix to remove
from all stored paths (if present), and cmd/go invoked
'go tool pack grcP $WORK' to remove references to the
temporary work directory.
We've changed the build to avoid pack as much as possible,
under the theory that instead of making pack convert from
.6 to .a, the tools should just write the .a directly and save a
round of I/O.
Instead of going back to invoking pack always, define a common
flag -trimpath in the assemblers, C compilers, and Go compilers,
implemented in liblink, and arrange for cmd/go to use the flag.
Then the object files being written out have the shortened paths
from the start.
While we are here, reimplement pcln support for GOROOT_FINAL.
A build in /tmp/go uses GOROOT=/tmp/go, but if GOROOT_FINAL=/usr/local/go
is set, then a source file named /tmp/go/x.go is recorded instead as
/usr/local/go/x.go. We use this so that we can prepare distributions
to be installed in /usr/local/go without actually working in that
directory. The conversion to liblink deleted all the old file name
handling code, including the GOROOT_FINAL translation.
Bring the GOROOT_FINAL translation back.
Before this CL, using GOROOT_FINAL=/goroot make.bash:
g% strings $(which go) | grep -c $TMPDIR
6
g% strings $(which go) | grep -c $GOROOT
793
g%
After this CL:
g% strings $(which go) | grep -c $TMPDIR
0
g% strings $(which go) | grep -c $GOROOT
0
g%
(The references to $TMPDIR tend to be cgo-generated source files.)
Adding the -trimpath flag to the assemblers required converting
them to the new Go-semantics flag parser. The text in go1.3.html
is copied and adjusted from go1.1.html, which is when we applied
that conversion to the compilers and linkers.
Fixes#6989.
LGTM=iant
R=r, iant
CC=golang-codereviews
https://golang.org/cl/88300045
My cmd/go got in a weird state where it started invoking pack grcP.
Change pack to print a 1-line explanation of the usage problem
before the generic usage message.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/87770047
OpenBSD is excluded from all the usual thread-local storage
code, not just emitting the tbss section in the external link .o
but emitting a PT_TLS section in an internally-linked executable.
I assume it just has no proper TLS support. Exclude it here too.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/87900045
When I did the original 386 ports on Linux and OS X, I chose to
define GS-relative expressions like 4(GS) as relative to the actual
thread-local storage base, which was usually GS but might not be
(it might be FS, or it might be a different constant offset from GS or FS).
The original scope was limited but since then the rewrites have
gotten out of control. Sometimes GS is rewritten, sometimes FS.
Some ports do other rewrites to enable shared libraries and
other linking. At no point in the code is it clear whether you are
looking at the real GS/FS or some synthesized thing that will be
rewritten. The code manipulating all these is duplicated in many
places.
The first step to fixing issue 7719 is to make the code intelligible
again.
This CL adds an explicit TLS pseudo-register to the 386 and amd64.
As a register, TLS refers to the thread-local storage base, and it
can only be loaded into another register:
MOVQ TLS, AX
An offset from the thread-local storage base is written off(reg)(TLS*1).
Semantically it is off(reg), but the (TLS*1) annotation marks this as
indexing from the loaded TLS base. This emits a relocation so that
if the linker needs to adjust the offset, it can. For example:
MOVQ TLS, AX
MOVQ 8(AX)(TLS*1), CX // load m into CX
On systems that support direct access to the TLS memory, this
pair of instructions can be reduced to a direct TLS memory reference:
MOVQ 8(TLS), CX // load m into CX
The 2-instruction and 1-instruction forms correspond roughly to
ELF TLS initial exec mode and ELF TLS local exec mode, respectively.
Liblink applies this rewrite on systems that support the 1-instruction form.
The decision is made using only the operating system (and probably
the -shared flag, eventually), not the link mode. If some link modes
on a particular operating system require the 2-instruction form,
then all builds for that operating system will use the 2-instruction
form, so that the link mode decision can be delayed to link time.
Obviously it is late to be making changes like this, but I despair
of correcting issue 7719 and issue 7164 without it. To make sure
I am not changing existing behavior, I built a "hello world" program
for every GOOS/GOARCH combination we have and then worked
to make sure that the rewrite generates exactly the same binaries,
byte for byte. There are a handful of TODOs in the code marking
kludges to get the byte-for-byte property, but at least now I can
explain exactly how each binary is handled.
The targets I tested this way are:
darwin-386
darwin-amd64
dragonfly-386
dragonfly-amd64
freebsd-386
freebsd-amd64
freebsd-arm
linux-386
linux-amd64
linux-arm
nacl-386
nacl-amd64p32
netbsd-386
netbsd-amd64
openbsd-386
openbsd-amd64
plan9-386
plan9-amd64
solaris-amd64
windows-386
windows-amd64
There were four exceptions to the byte-for-byte goal:
windows-386 and windows-amd64 have a time stamp
at bytes 137 and 138 of the header.
darwin-386 and plan9-386 have five or six modified
bytes in the middle of the Go symbol table, caused by
editing comments in runtime/sys_{darwin,plan9}_386.s.
Fixes#7164.
LGTM=iant
R=iant, aram, minux.ma, dave
CC=golang-codereviews
https://golang.org/cl/87920043
This breaks "go get -d repo/path/...".
««« original CL description
cmd/go: do not miss an error if import path contains "cmd/something"
Fixes#7638
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/87300043
»»»
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/87890043
The relocation and automatic variable types were using
arch-specific numbers. Introduce portable enumerations
instead.
To the best of my knowledge, these are the only arch-specific
bits left in the new object file format.
Remove now, before Go 1.3, because file formats are forever.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/87670044
There are changes we know we want to make, but not before Go 1.3
Add a version number so that we can make them more easily later.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/87670043
These are not ready and will not be in Go 1.3.
Fixes#6932.
LGTM=bradfitz
R=golang-codereviews, bradfitz, minux.ma
CC=golang-codereviews, iant, r
https://golang.org/cl/87630043
We have never released cmd/prof and don't plan to.
Now that nm, addr2line, and objdump have been rewritten in Go,
cmd/prof is the only thing keeping us from deleting libmach.
Delete cmd/prof, and then since nothing is using libmach, delete libmach.
13,000 lines of C deleted.
LGTM=minux.ma
R=golang-codereviews, minux.ma
CC=golang-codereviews, iant, r
https://golang.org/cl/87020044
Update cmd/dist not to build the C version.
Update cmd/go to install the Go version to the tool directory.
Update #7452
This is the basic logic needed for objdump, and it works well enough
to support the pprof list and weblist commands. A real disassembler
needs to be added in order to support the pprof disasm command
and the per-line assembly displays in weblist. That's still to come.
Probably objdump will move to go.tools when the disassembler
is added, but it can stay here for now.
LGTM=minux.ma
R=golang-codereviews, minux.ma
CC=golang-codereviews, iant, r
https://golang.org/cl/87580043
even when there are no *_test.go files present.
rsc suggested this change
Fixes#7108
LGTM=r, adg
R=golang-codereviews, r, adg
CC=golang-codereviews
https://golang.org/cl/84300043
On amd64p32 pointers are 32-bit-aligned and cannot be assumed to
have an offset multiple of widthreg. Instead check that they are
withptr-aligned.
Also change the threshold for region merging to 2*widthreg
instead of 2*widthptr because performance on amd64 and amd64p32
is expected to be the same.
Fixes#7712.
LGTM=khr
R=rsc, dave, khr, brad, bradfitz
CC=golang-codereviews
https://golang.org/cl/84690044
Add a $Context variable to the template so that the build.Context values
such as BuildTags can be accessed.
Fixes#6666.
LGTM=adg, rsc
R=golang-codereviews, gobot, adg, rsc
CC=golang-codereviews
https://golang.org/cl/72770043
Native Client forbids jumps/calls to arbitrary locations and
enforces a particular alignement, which makes the Duff's device
ineffective.
LGTM=khr
R=rsc, dave, khr
CC=golang-codereviews
https://golang.org/cl/84400043
Trying to make GODEBUG=gcdead=1 work with liveness
and in particular ambiguously live variables.
1. In the liveness computation, mark all ambiguously live
variables as live for the entire function, except the entry.
They are zeroed directly after entry, and we need them not
to be poisoned thereafter.
2. In the liveness computation, compute liveness (and deadness)
for all parameters, not just pointer-containing parameters.
Otherwise gcdead poisons untracked scalar parameters and results.
3. Fix liveness debugging print for -live=2 to use correct bitmaps.
(Was not updated for compaction during compaction CL.)
4. Correct varkill during map literal initialization.
Was killing the map itself instead of the inserted value temp.
5. Disable aggressive varkill cleanup for call arguments if
the call appears in a defer or go statement.
6. In the garbage collector, avoid bug scanning empty
strings. An empty string is two zeros. The multiword
code only looked at the first zero and then interpreted
the next two bits in the bitmap as an ordinary word bitmap.
For a string the bits are 11 00, so if a live string was zero
length with a 0 base pointer, the poisoning code treated
the length as an ordinary word with code 00, meaning it
needed poisoning, turning the string into a poison-length
string with base pointer 0. By the same logic I believe that
a live nil slice (bits 11 01 00) will have its cap poisoned.
Always scan full multiword struct.
7. In the runtime, treat both poison words (PoisonGC and
PoisonStack) as invalid pointers that warrant crashes.
Manual testing as follows:
- Create a script called gcdead on your PATH containing:
#!/bin/bash
GODEBUG=gcdead=1 GOGC=10 GOTRACEBACK=2 exec "$@"
- Now you can build a test and then run 'gcdead ./foo.test'.
- More importantly, you can run 'go test -short -exec gcdead std'
to run all the tests.
Fixes#7676.
While here, enable the precise scanning of slices, since that was
disabled due to bugs like these. That now works, both with and
without gcdead.
Fixes#7549.
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/83410044
runtime.Version() requires a trailing "+" when
tree had local modifications at time of build.
Fixes#7701
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/84040045
Brad has been asking for this for a while.
I have resisted because I wanted to find a more general way to
do this, one that would keep the performance of code introducing
variables the same as the performance of code that did not.
(See golang.org/issue/3512#c20).
I have not found the more general way, and recent changes to
remove ambiguously live temporaries have blown away the
property I was trying to preserve, so that's no longer a reason
not to make the change.
Fixes#3512.
LGTM=iant
R=iant
CC=bradfitz, golang-codereviews, khr, r
https://golang.org/cl/83740044
Cuts hello world by 70kB, because we don't write
those names into the symbol table.
Update #6853
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/80370045
The data field is the generic array that acts as a standin
for the keys and values arrays for the generic runtime code.
We want to substitute the keys and values arrays for the data
array, not just add keys and values in addition to it.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/81160044
Darwin 10.6 (gcc 4.2) and some older versions of gcc default to C90 mode, not C99 mode. Silence the warning.
LGTM=aram, iant
R=golang-codereviews, aram, iant
CC=golang-codereviews
https://golang.org/cl/83090050
Reduce footprint of liveness bitmaps by about 5x.
1. Mark all liveness bitmap symbols as 4-byte aligned
(they were aligned to a larger size by default).
2. The bitmap data is a bitmap count n followed by n bitmaps.
Each bitmap begins with its own count m giving the number
of bits. All the m's are the same for the n bitmaps.
Emit this bitmap length once instead of n times.
3. Many bitmaps within a function have the same bit values,
but each call site was given a distinct bitmap. Merge duplicate
bitmaps so that no bitmap is written more than once.
4. Many functions end up with the same aggregate bitmap data.
We used to name the bitmap data funcname.gcargs and funcname.gclocals.
Instead, name it gclocals.<md5 of data> and mark it dupok so
that the linker coalesces duplicate sets. This cut the bitmap
data remaining after step 3 by 40%; I was not expecting it to
be quite so dramatic.
Applied to "go build -ldflags -w code.google.com/p/go.tools/cmd/godoc":
bitmaps pclntab binary on disk
before this CL 1326600 1985854 12738268
4-byte align 1154288 (0.87x) 1985854 (1.00x) 12566236 (0.99x)
one bitmap len 782528 (0.54x) 1985854 (1.00x) 12193500 (0.96x)
dedup bitmap 414748 (0.31x) 1948478 (0.98x) 11787996 (0.93x)
dedup bitmap set 245580 (0.19x) 1948478 (0.98x) 11620060 (0.91x)
While here, remove various dead blocks of code from plive.c.
Fixes#6929.
Fixes#7568.
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/83630044
warning: src/cmd/8g/ggen.c:35 non-interruptable temporary
warning: src/cmd/gc/walk.c:656 set and not used: l
warning: src/cmd/gc/walk.c:658 set and not used: l
LGTM=minux.ma
R=golang-codereviews, minux.ma
CC=golang-codereviews
https://golang.org/cl/83660043
1. Use n->alloc, not n->left, to hold the allocated temp being
passed from orderstmt/orderexpr to walk.
2. Treat method values the same as closures.
3. Use killed temporary for composite literal passed to
non-escaping function argument.
4. Clean temporaries promptly in if and for statements.
5. Clean temporaries promptly in select statements.
As part of this, move all the temporary-generating logic
out of select.c into order.c, so that the temporaries can
be reclaimed.
With the new temporaries, can re-enable the 1-entry
select optimization. Fixes issue 7672.
While we're here, fix a 1-line bug in select processing
turned up by the new liveness test (but unrelated; select.c:72).
Fixes#7686.
6. Clean temporaries (but not particularly promptly) in switch
and range statements.
7. Clean temporary used during convT2E/convT2I.
8. Clean temporaries promptly during && and || expressions.
---
CL 81940043 reduced the number of ambiguously live temps
in the godoc binary from 860 to 711.
CL 83090046 reduced the number from 711 to 121.
This CL reduces the number from 121 to 23.
15 the 23 that remain are in fact ambiguously live.
The final 8 could be fixed but are not trivial and
not common enough to warrant work at this point
in the release cycle.
These numbers only count ambiguously live temps,
not ambiguously live user-declared variables.
There are 18 such variables in the godoc binary after this CL,
so a total of 41 ambiguously live temps or user-declared
variables.
The net effect is that zeroing anything on entry to a function
should now be a rare event, whereas earlier it was the
common case.
This is good enough for Go 1.3, and probably good
enough for future releases too.
Fixes#7345.
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/83000048
1. In functions with heap-allocated result variables or with
defer statements, the return sequence requires more than
just a single RET instruction. There is an optimization that
arranges for all returns to jump to a single copy of the return
epilogue in this case. Unfortunately, that optimization is
fundamentally incompatible with PC-based liveness information:
it takes PCs at many different points in the function and makes
them all land at one PC, making the combined liveness information
at that target PC a mess. Disable this optimization, so that each
return site gets its own copy of the 'call deferreturn' and the
copying of result variables back from the heap.
This removes quite a few spurious 'ambiguously live' variables.
2. Let orderexpr allocate temporaries that are passed by address
to a function call and then die on return, so that we can arrange
an appropriate VARKILL.
2a. Do this for ... slices.
2b. Do this for closure structs.
2c. Do this for runtime.concatstring, which is the implementation
of large string additions. Change representation of OADDSTR to
an explicit list in typecheck to avoid reconstructing list in both
walk and order.
3. Let orderexpr allocate the temporary variable copies used for
range loops, so that they can be killed when the loop is over.
Similarly, let it allocate the temporary holding the map iterator.
CL 81940043 reduced the number of ambiguously live temps
in the godoc binary from 860 to 711.
This CL reduces the number to 121. Still more to do, but another
good checkpoint.
Update #7345
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/83090046
REP MOVSQ and REP STOSQ have a really high startup overhead.
Use a Duff's device to do the repetition instead.
benchmark old ns/op new ns/op delta
BenchmarkClearFat32 7.20 1.60 -77.78%
BenchmarkCopyFat32 6.88 2.38 -65.41%
BenchmarkClearFat64 7.15 3.20 -55.24%
BenchmarkCopyFat64 6.88 3.44 -50.00%
BenchmarkClearFat128 9.53 5.34 -43.97%
BenchmarkCopyFat128 9.27 5.56 -40.02%
BenchmarkClearFat256 13.8 9.53 -30.94%
BenchmarkCopyFat256 13.5 10.3 -23.70%
BenchmarkClearFat512 22.3 18.0 -19.28%
BenchmarkCopyFat512 22.0 19.7 -10.45%
BenchmarkCopyFat1024 36.5 38.4 +5.21%
BenchmarkClearFat1024 35.1 35.0 -0.28%
TODO: use for stack frame zeroing
TODO: REP prefixes are still used for "reverse" copying when src/dst
regions overlap. Might be worth fixing.
LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews, r
https://golang.org/cl/81370046
The new channel and map runtime routines take pointers
to values, typically temporaries. Without help, the compiler
cannot tell when those temporaries stop being needed,
because it isn't sure what happened to the pointer.
Arrange to insert explicit VARKILL instructions for these
temporaries so that the liveness analysis can avoid seeing
them as "ambiguously live".
The change is made in order.c, which was already in charge of
introducing temporaries to preserve the order-of-evaluation
guarantees. Now its job has expanded to include introducing
temporaries as needed by runtime routines, and then also
inserting the VARKILL annotations for all these temporaries,
so that their lifetimes can be shortened.
In order to do its job for the map runtime routines, order.c arranges
that all map lookups or map assignments have the form:
x = m[k]
x, y = m[k]
m[k] = x
where x, y, and k are simple variables (often temporaries).
Likewise, receiving from a channel is now always:
x = <-c
In order to provide the map guarantee, order.c is responsible for
rewriting x op= y into x = x op y, so that m[k] += z becomes
t = m[k]
t2 = t + z
m[k] = t2
While here, fix a few bugs in order.c's traversal: it was failing to
walk into select and switch case bodies, so order of evaluation
guarantees were not preserved in those situations.
Added tests to test/reorder2.go.
Fixes#7671.
In gc/popt's temporary-merging optimization, allow merging
of temporaries with their address taken as long as the liveness
ranges do not intersect. (There is a good chance of that now
that we have VARKILL annotations to limit the liveness range.)
Explicitly killing temporaries cuts the number of ambiguously
live temporaries that must be zeroed in the godoc binary from
860 to 711, or -17%. There is more work to be done, but this
is a good checkpoint.
Update #7345
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/81940043
e.g., don't delete /dev/null. this fix inspired by gnu libiberty,
unlink-if-ordinary.c.
Fixes#7563
LGTM=iant
R=golang-codereviews, iant, 0intro
CC=golang-codereviews, r
https://golang.org/cl/76810045
chanrecv now expects a pointer to the data to be filled in.
mapiterinit expects a pointer to the hash iterator to be filled in.
In both cases, the temporary being pointed at changes from
dead to alive during the call. In order to make sure it is
preserved if a garbage collection happens after that transition
but before the call returns, the temp must be marked as live
during the entire call.
But if it is live during the entire call, it needs to be safe for
the garbage collector to scan at the beginning of the call,
before the new data has been filled in. Therefore, it must be
zeroed by the caller, before the call. Do that.
My previous attempt waited to mark it live until after the
call returned, but that's unsafe (see first paragraph);
undo that change in plive.c.
This makes powser2 pass again reliably.
I looked at every call to temp in the compiler.
The vast majority are followed immediately by an
initialization of temp, so those are fine.
The only ones that needed changing were the ones
where the next operation is to pass the address of
the temp to a function call, and there aren't too many.
Maps are exempted from this because mapaccess
returns a pointer to the data and lets the caller make
the copy.
Fixes many builds.
TBR=khr
CC=golang-codereviews
https://golang.org/cl/80700046
cgo represents all 0-sized and unsized types internally as [0]byte. This means that pointers to incomplete types would be interchangable, even if given a name by typedef.
Fixes#7409.
LGTM=iant
R=golang-codereviews, bradfitz, iant
CC=golang-codereviews
https://golang.org/cl/76450043
1. On entry to a function, only zero the ambiguously live stack variables.
Before, we were zeroing all stack variables containing pointers.
The zeroing is pretty inefficient right now (issue 7624), but there are also
too many stack variables detected as ambiguously live (issue 7345),
and that must be addressed before deciding how to improve the zeroing code.
(Changes in 5g/ggen.c, 6g/ggen.c, 8g/ggen.c, gc/pgen.c)
Fixes#7647.
2. Make the regopt word-based liveness analysis preserve the
whole-variable liveness property expected by the garbage collection
bitmap liveness analysis. That is, if the regopt liveness decides that
one word in a struct needs to be preserved, make sure it preserves
the entire struct. This is particularly important for multiword values
such as strings, slices, and interfaces, in which all the words need
to be present in order to understand the meaning.
(Changes in 5g/reg.c, 6g/reg.c, 8g/reg.c.)
Fixes#7591.
3. Make the regopt word-based liveness analysis treat a variable
as having its address taken - which makes it preserved across
all future calls - whenever n->addrtaken is set, for consistency
with the gc bitmap liveness analysis, even if there is no machine
instruction actually taking the address. In this case n->addrtaken
is incorrect (a nicer way to put it is overconservative), and ideally
there would be no such cases, but they can happen and the two
analyses need to agree.
(Changes in 5g/reg.c, 6g/reg.c, 8g/reg.c; test in bug484.go.)
Fixes crashes found by turning off "zero everything" in step 1.
4. Remove spurious VARDEF annotations. As the comment in
gc/pgen.c explains, the VARDEF must immediately precede
the initialization. It cannot be too early, and it cannot be too late.
In particular, if a function call sits between the VARDEF and the
actual machine instructions doing the initialization, the variable
will be treated as live during that function call even though it is
uninitialized, leading to problems.
(Changes in gc/gen.c; test in live.go.)
Fixes crashes found by turning off "zero everything" in step 1.
5. Do not treat loading the address of a wide value as a signal
that the value must be initialized. Instead depend on the existence
of a VARDEF or the first actual read/write of a word in the value.
If the load is in order to pass the address to a function that does
the actual initialization, treating the load as an implicit VARDEF
causes the same problems as described in step 4.
The alternative is to arrange to zero every such value before
passing it to the real initialization function, but this is a much
easier and more efficient change.
(Changes in gc/plive.c.)
Fixes crashes found by turning off "zero everything" in step 1.
6. Treat wide input parameters with their address taken as
initialized on entry to the function. Otherwise they look
"ambiguously live" and we will try to emit code to zero them.
(Changes in gc/plive.c.)
Fixes crashes found by turning off "zero everything" in step 1.
7. An array of length 0 has no pointers, even if the element type does.
Without this change, the zeroing code complains when asked to
clear a 0-length array.
(Changes in gc/reflect.c.)
LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/80160044
Zeroing the outputs makes sure that during function calls
in those functions we do not let the garbage collector
treat uninitialized values as pointers.
The garbage collector may still see uninitialized values
if a preemption occurs during the function prologue,
before the zeroing has had a chance to run.
This reduces the number of 'bad pointer' messages when
that runtime check is enabled, but it doesn't fix all of them,
so the check is still disabled.
It will also avoid leaks, although I doubt any of these were
particularly serious.
LGTM=iant, khr
R=iant, khr
CC=golang-codereviews
https://golang.org/cl/80850044
If you compile a program that has cgo LDFLAGS directives, those are exported to an environment variable to be used by subsequent compiler tool invocations. The linking phase when using the gccgo toolchain did not consider the envvar CGO_LDFLAGS's linking directives resulting in undefined references when using cgo+gccgo.
Fixes#7573
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/80780043
GCC on OS X 10.6 doesn't support -Wuninitialized without -O.
Fixes#7492.
LGTM=iant
R=golang-codereviews, dave, iant
CC=golang-codereviews
https://golang.org/cl/72360045
Fixes#7627.
CL 61970044 changed the order in which .a files are passed to gccgo's link phase. However by reversing the order it caused gccgo to complain if both internal (liba.a) and external (liba_test.a) versions of a package were presented as the former would not contain all the necessary symbols, and the latter would duplicate symbols already defined.
This change ensures that all 'fake' targets remain at the top of the final link order which should be fine as a package compiled as an external test is a superset of its internal sibling.
Looking at how gcToolchain links tests I think this change now accurately mirrors those actions which present $WORK/_test before $WORK in the link order.
LGTM=iant
R=rsc, iant
CC=golang-codereviews, michael.hudson
https://golang.org/cl/80300043
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
Revision 3ae4607a43ff introduced CONVNOP layers
to fix type checking issues arising from comparisons.
The added complexity made 8g run out of registers
when compiling an equality function in go.net/ipv6.
A similar issue occurred in test/sizeof.go on
amd64p32 with 6g.
Fixes#7405.
LGTM=khr
R=rsc, dave, iant, khr
CC=golang-codereviews
https://golang.org/cl/78100044
Removes most uses of the REP prefix, which has a high startup cost.
LGTM=iant
R=golang-codereviews, iant, khr
CC=golang-codereviews
https://golang.org/cl/77920043
A too large float constant is an error.
A too small float constant is rounded to zero.
Fixes#7419
Update #6902
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/76730046
Old versions of DTrace (as those shipped in OS X and FreeBSD)
don't support unicode characters in symbol names. Replace '·'
to '.' to make DTrace happy.
Fixes#7493
LGTM=aram, rsc
R=aram, rsc, gobot, iant
CC=golang-codereviews
https://golang.org/cl/72280043
The lowering to runtime calls introduces hidden pointers to the
arguments of select clauses. When implicit conversions were
involved it could end up with incompatible pointers. Since the
pointed-to types have the same representation, we can introduce a
forced conversion.
Fixes#6847.
LGTM=rsc
R=rsc, iant, khr
CC=golang-codereviews
https://golang.org/cl/72380043
It was using a REP STOSQ but putting in CX the number of 32-bit
words to clear.
LGTM=dave
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/75240043
Under some circumstances, gccgoToolchain's ld can pass the path of
build outputs that have been deleted to the link command.
Fixes#7303.
LGTM=rsc
R=golang-codereviews, dave, michael.hudson, rsc
CC=golang-codereviews
https://golang.org/cl/61970044
The compilers expect to not be interrupted by floating
point exceptions. On Plan 9, every process starts with
interrupts enabled for invalid operation, stack overflow,
and divide by zero exceptions.
LGTM=rsc
R=rsc, 0intro
CC=golang-codereviews
https://golang.org/cl/72750043
Acid can't produce a stack trace without .frame symbols.
Of course, it can only unwind through linear stacks but
this is still better than nothing. (I wrote an acid func
to do the full unwind a long time ago but lost it and
haven't worked up the courage to write it again).
Note that these will only be present in the native symbol
table for Plan 9 binaries.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/72450045
debuglive >= 1 is not the condition under which we
start recording messages (we avoid printing for
init functions even if debuglive is set).
LGTM=bradfitz, iant
R=golang-codereviews, bradfitz
CC=golang-codereviews, iant, khr
https://golang.org/cl/74390043
This fixes the following amd64p32 issue:
pkg/time/format.go:724: internal compiler error: twobitwalktype1: invalid initial alignment, Time
caused by the pointer zone ending on a 32-bit-aligned boundary.
LGTM=rsc
R=rsc, dave
CC=golang-codereviews
https://golang.org/cl/72270046
Replaces CL 70000043.
Switch to the amd64p32 linker model if we are building under nacl/amd64p32.
No need to introduce linkarchinit() as 6a contains its own main() function.
LGTM=rsc
R=rsc, minux.ma
CC=golang-codereviews
https://golang.org/cl/72020043
Replaces CL 70000043.
Introduce linkarchinit() from cmd/ld.
For cmd/6g, switch to the amd64p32 linker model if we are building under nacl/amd64p32.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/71330045
This is a test case for CL 34680044.
Fixes#6333.
LGTM=bradfitz
R=golang-codereviews, bradfitz, minux.ma
CC=golang-codereviews
https://golang.org/cl/71230049
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
Tested GOARM=6 on Raspberry Pi, and I found only a few tests that
use sub-normal numbers fails. I have a patch to NetBSD kernel pending
that fixes this issue (NetBSD kernel doesn't allow us to disable the
Flush-to-Zero feature).
LGTM=jsing
R=golang-codereviews, jsing
CC=golang-codereviews
https://golang.org/cl/70730043
Essentialy for running tests without a working cmd/go.
While we're at it, also fix a typo.
LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/70640043
Recently NetBSD starts to enforce this, and refuses to execute
the program if n is larger than the sum of entry sizes.
Before:
$ readelf -n ../bin/go.old
Notes at offset 0x00000bd0 with length 0x00000019:
Owner Data size Description
NetBSD 0x00000004 NT_VERSION (version)
readelf: Warning: corrupt note found at offset 18 into core notes
readelf: Warning: type: 0, namesize: 00000000, descsize: 00000000
$ readelf -n ../bin/go
Notes at offset 0x00000bd0 with length 0x00000018:
Owner Data size Description
NetBSD 0x00000004 NT_VERSION (version)
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/70710043
Add CgoFiles to the covered files when building
with cover support.
LGTM=rsc
R=golang-codereviews, gobot, r, rsc
CC=golang-codereviews
https://golang.org/cl/34680044
Apparently, the Windows routines sometimes fail to generate output.
Copy the Unix stdio-based implementations instead.
Suggested by Pietro Gagliardi in CL 65280043 but that CL
seems to have been abandoned.
Fixes#7242.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/71550044
For non-closure functions, the context register is uninitialized
on entry and will not be used, but morestack saves it and then the
garbage collector treats it as live. This can be a source of memory
leaks if the context register points at otherwise dead memory.
Avoid this by introducing a parallel set of morestack functions
that clear the context register, and use those for the non-closure functions.
I hope this will help with some of the finalizer flakiness, but it probably won't.
Fixes#7244.
LGTM=dvyukov
R=khr, dvyukov
CC=golang-codereviews
https://golang.org/cl/71030044
warning: src/cmd/ld/pcln.c:184 more arguments than format INT
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/69870047
The pcln file number was being encoded incorrectly. The recorded delta was always against -1, not against the previous value.
Update #7369
This CL fixes the bad DWARF file numbers. It does not, however, fix the gdb continue-to-end bug.
LGTM=iant
R=rsc, minux.ma, iant
CC=golang-codereviews, graham
https://golang.org/cl/68960046
This CL replays the following one CL from the rsc-go13nacl repo.
This is the last replay CL: after this CL the main repo will have
everything the rsc-go13nacl repo did. Changes made to the main
repo after the rsc-go13nacl repo branched off probably mean that
NaCl doesn't actually work after this CL, but all the code is now moved
over and just needs to be redebugged.
---
cmd/6l, cmd/8l, cmd/ld: support for Native Client
See golang.org/s/go13nacl for design overview.
This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.
This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.
R≡khr
https://golang.org/cl/15750044
---
LGTM=bradfitz, dave, iant
R=dave, bradfitz, iant
CC=golang-codereviews
https://golang.org/cl/69040044
The cached computed interface tables are indexed by the interface
types, not by the unnamed underlying interfaces
To preserve the invariants expected by interface comparison, an
itab generated for an interface type must not be used for a value
of a different interface type even if the representation is identical.
Fixes#7207.
LGTM=rsc
R=rsc, iant, khr
CC=golang-codereviews
https://golang.org/cl/69210044
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
The gvardef function does nothing if n->class == PEXTERN, so
we don't need to test for that before calling it. This makes
the 6g/8g code more like the 5g code and clarifies that the
cases that do not test for n->class != PEXTERN are not buggy.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/68900044
maxstksize is superfluous and appears to be vestigial. 6g does not use it.
c >= 4 cannot occur; c = w % 4.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/68750043
These previously reviewed CLs are present in this CL.
---
changeset: 18445:436bb084caed
user: Russ Cox <rsc@golang.org>
date: Mon Nov 11 09:50:34 2013 -0500
description:
runtime: assembly and system calls for Native Client x86-64
See golang.org/s/go13nacl for design overview.
This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.
This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.
R≡adg
https://golang.org/cl/15760044
---
changeset: 18448:90bd871b5994
user: Russ Cox <rsc@golang.org>
date: Mon Nov 11 09:51:36 2013 -0500
description:
runtime: amd64p32 and Native Client assembly bootstrap
See golang.org/s/go13nacl for design overview.
This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.
This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.
R≡khr
https://golang.org/cl/15820043
---
changeset: 18449:b011c3dc687e
user: Russ Cox <rsc@golang.org>
date: Mon Nov 11 09:51:58 2013 -0500
description:
math: amd64p32 assembly routines
These routines only manipulate float64 values,
so the amd64 and amd64p32 can share assembly.
The large number of files is symptomatic of a problem
with package path: it is a Go package structured like a C library.
But that will need to wait for another day.
See golang.org/s/go13nacl for design overview.
This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.
This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.
R≡bradfitz
https://golang.org/cl/15870043
---
changeset: 18450:43234f082eec
user: Russ Cox <rsc@golang.org>
date: Mon Nov 11 10:03:19 2013 -0500
description:
syscall: networking for Native Client
See golang.org/s/go13nacl for design overview.
This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.
This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.
R≡rsc
https://golang.org/cl/15780043
---
changeset: 18451:9c8d1d890aaa
user: Russ Cox <rsc@golang.org>
date: Mon Nov 11 10:03:34 2013 -0500
description:
runtime: assembly and system calls for Native Client x86-32
See golang.org/s/go13nacl for design overview.
This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.
This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.
R≡rsc
https://golang.org/cl/15800043
---
changeset: 18452:f90b1dd9228f
user: Russ Cox <rsc@golang.org>
date: Mon Nov 11 11:04:09 2013 -0500
description:
runtime: fix frame size for linux/amd64 runtime.raise
R≡rsc
https://golang.org/cl/24480043
---
changeset: 18445:436bb084caed
user: Russ Cox <rsc@golang.org>
date: Mon Nov 11 09:50:34 2013 -0500
description:
runtime: assembly and system calls for Native Client x86-64
See golang.org/s/go13nacl for design overview.
This CL is publicly visible but not CC'ed to golang-dev,
to avoid distracting from the preparation of the Go 1.2
release.
This CL and the others will be checked into my rsc-go13nacl
clone repo for now, and I will send CLs against the main
repo early in the Go 1.3 development.
R≡adg
https://golang.org/cl/15760044
---
changeset: 18455:53b06799a938
user: Russ Cox <rsc@golang.org>
date: Mon Nov 11 23:29:52 2013 -0500
description:
cmd/gc: add -nolocalimports flag
R≡dsymonds
https://golang.org/cl/24990043
---
changeset: 18456:24f64e1eaa8a
user: Russ Cox <rsc@golang.org>
date: Tue Nov 12 22:06:29 2013 -0500
description:
runtime: add comments for playback write
R≡adg
https://golang.org/cl/25190043
---
changeset: 18457:d1f615bbb6e4
user: Russ Cox <rsc@golang.org>
date: Wed Nov 13 17:03:52 2013 -0500
description:
runtime: write only to NaCl stdout, never to NaCl stderr
NaCl writes some other messages on standard error
that we would like to be able to squelch.
R≡adg
https://golang.org/cl/26240044
---
changeset: 18458:1f01be1a1dc2
tag: tip
user: Russ Cox <rsc@golang.org>
date: Wed Nov 13 19:45:16 2013 -0500
description:
runtime: remove apparent debugging dreg
Setting timens to 0 turns off fake time.
TBR≡adg
https://golang.org/cl/26400043
LGTM=bradfitz
R=dave, bradfitz
CC=golang-codereviews
https://golang.org/cl/68730043
The parser was assuming it would find <body> or </head>.
If the entire response is just <meta> tags, it finds EOF and
treats that as an error. It's not.
LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/68520044
The new flag was added by CL 68150047 (part of the NaCl replay),
but the change, like the original, omitted documentation of the
new behavior.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/68580043
See golang.org/s/go13nacl for design overview.
This CL is the mostly mechanical changes from rsc's Go 1.2 based NaCl branch, specifically 39cb35750369 to 500771b477cf from https://code.google.com/r/rsc-go13nacl. This CL does not include working NaCl support, there are probably two or three more large merges to come.
CL 15750044 is not included as it involves more invasive changes to the linker which will need to be merged separately.
The exact change lists included are
15050047: syscall: support for Native Client
15360044: syscall: unzip implementation for Native Client
15370044: syscall: Native Client SRPC implementation
15400047: cmd/dist, cmd/go, go/build, test: support for Native Client
15410048: runtime: support for Native Client
15410049: syscall: file descriptor table for Native Client
15410050: syscall: in-memory file system for Native Client
15440048: all: update +build lines for Native Client port
15540045: cmd/6g, cmd/8g, cmd/gc: support for Native Client
15570045: os: support for Native Client
15680044: crypto/..., hash/crc32, reflect, sync/atomic: support for amd64p32
15690044: net: support for Native Client
15690048: runtime: support for fake time like on Go Playground
15690051: build: disable various tests on Native Client
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/68150047
Revision c0e0467635ec (cmd/gc: return canonical Node* from temp)
exposed original nodes of temporaries, allowing callers to mutate
their types.
In walkcompare a temporary could be typed as ideal because of
this. Additionnally, assignment of a comparison result to
a custom boolean type was broken.
Fixes#7366.
LGTM=rsc
R=rsc, iant, khr
CC=golang-codereviews
https://golang.org/cl/66930044
Fixes the output of go env so that variables can be set
more accurately when using Plan 9's rc shell. Specifically,
GOPATH may have multiple components and the current
representation is plain wrong. In practice, we probably
ought to change os. Getenv to produce the right result, but
that requires considerably more thought.
LGTM=rsc
R=golang-codereviews, gobot, rsc
CC=golang-codereviews
https://golang.org/cl/66600043
Package runtime's C functions written to be called from Go
started out written in C using carefully constructed argument
lists and the FLUSH macro to write a result back to memory.
For some functions, the appropriate parameter list ended up
being architecture-dependent due to differences in alignment,
so we added 'goc2c', which takes a .goc file containing Go func
declarations but C bodies, rewrites the Go func declaration to
equivalent C declarations for the target architecture, adds the
needed FLUSH statements, and writes out an equivalent C file.
That C file is compiled as part of package runtime.
Native Client's x86-64 support introduces the most complex
alignment rules yet, breaking many functions that could until
now be portably written in C. Using goc2c for those avoids the
breakage.
Separately, Keith's work on emitting stack information from
the C compiler would require the hand-written functions
to add #pragmas specifying how many arguments are result
parameters. Using goc2c for those avoids maintaining #pragmas.
For both reasons, use goc2c for as many Go-called C functions
as possible.
This CL is a replay of the bulk of CL 15400047 and CL 15790043,
both of which were reviewed as part of the NaCl port and are
checked in to the NaCl branch. This CL is part of bringing the
NaCl code into the main tree.
No new code here, just reformatting and occasional movement
into .h files.
LGTM=r
R=dave, alex.brainman, r
CC=golang-codereviews
https://golang.org/cl/65220044
Match used len(ar.files) == 0 to mean "match everything"
but it also deleted matched things from the list, so once you
had matched everything you asked for, match returned true
for whatever was left in the archive too.
Concretely, if you have an archive containing f1, f2, then
pack t foo.a f1
would match f1 and then, because len(ar.files) == 0 after
deleting f1 from the match list, also match f2.
Avoid the problem by recording explicitly whether match
matches everything.
LGTM=r, dsymonds
R=r, dsymonds
CC=golang-codereviews
https://golang.org/cl/65630046
Get more information to help understand build failure on Plan 9.
Also Windows.
(TestHello is failing because GOCHAR does not appear in output.
What does?)
Update #7362
LGTM=bradfitz
R=rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/66070044
[Repeat of CL 64100044, after 32-bit fix in CL 66170043.]
Precisestack makes stack collection completely precise,
in the sense that there are no "used and not set" errors
in the collection of stack frames, no times where the collector
reads a pointer from a stack word that has not actually been
initialized with a pointer (possibly a nil pointer) in that function.
The most important part is interfaces: precisestack means
that if reading an interface value, the interface value is guaranteed
to be initialized, meaning that the type word can be relied
upon to be either nil or a valid interface type word describing
the data word.
This requires additional zeroing of certain values on the stack
on entry, which right now costs about 5% overall execution
time in all.bash. That cost will come down before Go 1.3
(issue 7345).
There are at least two known garbage collector bugs right now,
issues 7343 and 7344. The first happens even without precisestack.
The second I have only seen with precisestack, but that does not
mean that precisestack is what causes it. In fact it is very difficult
to explain by what precisestack does directly. Precisestack may
be exacerbating an existing problem. Both of those issues are
marked for Go 1.3 as well.
The reasons for enabling precisestack now are to give it more
time to soak and because the copying stack work depends on it.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/65820044
The code here is being restored after its deletion in CL 14430048.
I restored the copy in cmd/6g in CL 56430043 but neglected the
other two.
This is the reason that enabling precisestack only worked on amd64.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/66170043
When Go 1.3 is released, this will keep existing
Go 1.2 build scripts that use 'go tool pack grc' working.
For efficiency, such scripts should be changed to
use 6g -pack instead, but keeping the old behavior
available enables a more graceful transition.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/66130043
There are probably more of these, but bound and len are 64 bits so use %lld
in message about array index out of bounds.
Fixes the 386 build.
LGTM=bradfitz, rsc
R=rsc, bradfitz
CC=golang-codereviews, rickarnoldjr
https://golang.org/cl/66110043
We never updated libmach for the new object file format,
so it the existing 'go tool addr2line' is broken.
Reimplement in Go to fix.
LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/66020043
The error message was previously off by one in all cases.
Fixes#7150.
LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/65850043
Update #6853
For an ephemeral binary - one created, run, and then deleted -
there is no need to write dwarf debug information, since the
binary will not be used with gdb. In this case, instruct the linker
not to spend time and disk space generating the debug information
by passing the -w flag to the linker.
Omitting dwarf information reduces the size of most binaries by 25%.
We may be more aggressive about this in the future.
LGTM=bradfitz, r
R=r, bradfitz
CC=golang-codereviews
https://golang.org/cl/65890043
Update #6853
Every function now has a gcargs and gclocals symbol
holding associated garbage collection information.
Put them all in the same meta-symbol as the go.func data
and then drop individual entries from symbol table.
Removing gcargs and gclocals reduces the size of a
typical binary by 10%.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/65870044
Update #6853
Nothing reads the Plan 9 symbol table anymore.
The last holdout was 'go tool nm', but since being rewritten in Go
it uses the standard symbol table for the binary format
(ELF, Mach-O, PE) instead.
Removing the Plan 9 symbol table saves ~15% disk space
on most binaries.
Two supporting changes included in this CL:
debug/gosym: use Go 1.2 pclntab to synthesize func-only
symbol table when there is no Plan 9 symbol table
debug/elf, debug/macho, debug/pe: ignore final EOF from ReadAt
LGTM=r
R=r, bradfitz
CC=golang-codereviews
https://golang.org/cl/65740045
The code was returning the original value rather than the cloned value
resulting in the tests not being repeatable.
Fixes#7111.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/65720045
broke 32-bit builds
««« original CL description
cmd/gc, runtime: enable precisestack by default
Precisestack makes stack collection completely precise,
in the sense that there are no "used and not set" errors
in the collection of stack frames, no times where the collector
reads a pointer from a stack word that has not actually been
initialized with a pointer (possibly a nil pointer) in that function.
The most important part is interfaces: precisestack means
that if reading an interface value, the interface value is guaranteed
to be initialized, meaning that the type word can be relied
upon to be either nil or a valid interface type word describing
the data word.
This requires additional zeroing of certain values on the stack
on entry, which right now costs about 5% overall execution
time in all.bash. That cost will come down before Go 1.3
(issue 7345).
There are at least two known garbage collector bugs right now,
issues 7343 and 7344. The first happens even without precisestack.
The second I have only seen with precisestack, but that does not
mean that precisestack is what causes it. In fact it is very difficult
to explain by what precisestack does directly. Precisestack may
be exacerbating an existing problem. Both of those issues are
marked for Go 1.3 as well.
The reasons for enabling precisestack now are to give it more
time to soak and because the copying stack work depends on it.
LGTM=r
R=r
CC=golang-codereviews, iant, khr
https://golang.org/cl/64100044
»»»
TBR=r
CC=golang-codereviews
https://golang.org/cl/65230043
Precisestack makes stack collection completely precise,
in the sense that there are no "used and not set" errors
in the collection of stack frames, no times where the collector
reads a pointer from a stack word that has not actually been
initialized with a pointer (possibly a nil pointer) in that function.
The most important part is interfaces: precisestack means
that if reading an interface value, the interface value is guaranteed
to be initialized, meaning that the type word can be relied
upon to be either nil or a valid interface type word describing
the data word.
This requires additional zeroing of certain values on the stack
on entry, which right now costs about 5% overall execution
time in all.bash. That cost will come down before Go 1.3
(issue 7345).
There are at least two known garbage collector bugs right now,
issues 7343 and 7344. The first happens even without precisestack.
The second I have only seen with precisestack, but that does not
mean that precisestack is what causes it. In fact it is very difficult
to explain by what precisestack does directly. Precisestack may
be exacerbating an existing problem. Both of those issues are
marked for Go 1.3 as well.
The reasons for enabling precisestack now are to give it more
time to soak and because the copying stack work depends on it.
LGTM=r
R=r
CC=golang-codereviews, iant, khr
https://golang.org/cl/64100044
Not recording the address being taken was causing
the liveness analysis not to preserve x in the absence
of direct references to x, which in turn was making the
net test fail with GOGC=0.
In addition to the test, this fixes a bug wherein
GOGC=0 go test -short net
crashed if liveness analysis was in use (like at tip, not like Go 1.2).
TBR=ken2
CC=golang-codereviews
https://golang.org/cl/64470043
This problem was discovered by reading the code.
I have not seen it in practice, nor do I have any ideas
on how to trigger it reliably in a test. But it's still worth
fixing.
TBR=ken2
CC=golang-codereviews
https://golang.org/cl/64370046
The VARDEF placement must be before the initialization
but after any final use. If you have something like s = ... using s ...
the rhs must be evaluated, then the VARDEF, then the lhs
assigned.
There is a large comment in pgen.c on gvardef explaining
this in more detail.
This CL also includes Ian's suggestions from earlier CLs,
namely commenting the use of mode in link.h and fixing
the precedence of the ~r check in dcl.c.
This CL enables the check that if liveness analysis decides
a variable is live on entry to the function, that variable must
be a function parameter (not a result, and not a local variable).
If this check fails, it indicates a bug in the liveness analysis or
in the generated code being analyzed.
The race detector generates invalid code for append(x, y...).
The code declares a temporary t and then uses cap(t) before
initializing t. The new liveness check catches this bug and
stops the compiler from writing out the buggy code.
Consequently, this CL disables the race detector tests in
run.bash until the race detector bug can be fixed
(golang.org/issue/7334).
Except for the race detector bug, the liveness analysis check
does not detect any problems (this CL and the previous CLs
fixed all the detected problems).
The net test still fails with GOGC=0 but the rest of the tests
now pass or time out (because GOGC=0 is so slow).
TBR=iant
CC=golang-codereviews
https://golang.org/cl/64170043
The existing tests issue4463.go and issue4654.go had failures at
typechecking and did not test walking the AST.
Fixes#7272.
LGTM=khr
R=khr, rsc, iant
CC=golang-codereviews
https://golang.org/cl/60550044
A previous CL added support for cross compiling with cgo, but
missed the GOOS check in cmd/go. Remove it.
Update #4714
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/57210046
When the liveness code doesn't know a function doesn't return
(but the generated code understands that), the liveness analysis
invents a control flow edge that is not really there, which can cause
variables to seem spuriously live. This is particularly bad when the
variables are uninitialized.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/63720043
The registerization code needs the function to end in a RET,
even if that RET is actually unreachable.
The liveness code needs to avoid such unreachable RETs.
It had a special case for final RET after JMP, but no case
for final RET after UNDEF. Instead of expanding the special
cases, let fixjmp - which already knows what is and is not
reachable definitively - mark the unreachable RET so that
the liveness code can identify it.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/63680043
A normal RET is treated as using the return values,
but a tail jump RET does not - it is jumping to the
function that is going to fill in the return values.
If a tail jump RET is recorded as using the return values,
since nothing initializes them they will be marked as
live on entry to the function, which is clearly wrong.
Found and tested by the new code in plive.c that looks
for variables that are incorrectly live on entry.
That code is disabled for now because there are other
cases remaining to be fixed. But once it is enabled,
test/live1.go becomes a real test of this CL.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/63570045
Any initialization of a variable by a block copy or block zeroing
or by multiple assignments (componentwise copying or zeroing
of a multiword variable) needs to emit a VARDEF. These cases were not.
Fixes#7205.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/63650044
The test added in CL 63630043 fails on 5g and 8g because they
were not emitting the VARDEF instruction when clearing a fat
value by clearing the components. 6g had the call in the right place.
Hooray tests.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/63660043
The "fat" referred to being used for multiword values only.
We're going to use it for non-fat values sometimes too.
No change other than the renaming.
TBR=iant
CC=golang-codereviews
https://golang.org/cl/63650043
Old:
prog.go:9: invalid operation: this[i] (index of type int)
New:
prog.go:9: invalid operation: this[i] (type int does not support indexing)
LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/52540043
Before, an unnamed return value turned into an ONAME node n with n->sym
named ~anon%d, and n->orig == n.
A blank-named return value turned into an ONAME node n with n->sym
named ~anon%d but n->orig == the original blank n. Code generation and
printing uses n->orig, so that this node formatted as _.
But some code does not use n->orig. In particular the liveness code does
not know about the n->orig convention and so mishandles blank identifiers.
It is possible to fix but seemed better to avoid the confusion entirely.
Now the first kind of node is named ~r%d and the second ~b%d; both have
n->orig == n, so that it doesn't matter whether code uses n or n->orig.
After this change the ->orig field is only used for other kinds of expressions,
not for ONAME nodes.
This requires distinguishing ~b from ~r names in a few places that care.
It fixes a liveness analysis bug without actually changing the liveness code.
TBR=ken2
CC=golang-codereviews
https://golang.org/cl/63630043
Make the loop nesting depth of &x depend on where x is declared,
not on where the &x appears. The latter is only a conservative
estimate of the former. Being more careful can avoid some
variables escaping, and it is easier to reason about.
It would have avoided issue 7313, although that was still a bug
worth fixing.
Not much effect in the tree: one variable in the whole tree
is saved from a heap allocation (something in x509 parsing).
LGTM=daniel.morsing
R=daniel.morsing
CC=golang-codereviews
https://golang.org/cl/62380043
for example, we now rewrite *_Ctype_int to *C.int.
Fixes#6781.
LGTM=iant
R=golang-codereviews, rsc, iant
CC=golang-codereviews
https://golang.org/cl/36860043
Logically, the init statement is in the enclosing scopes loopdepth, not inside the for loop.
Fixes#7313.
LGTM=rsc
R=golang-codereviews, gobot, rsc
CC=golang-codereviews
https://golang.org/cl/62430043
go/build is changed to list the .m files in a package, and match them for build constraints, adding them to a new field: Package.MFiles.
The go tool is changed to support building .m files and linking in the results during CGO and SWIG builds. This means packages that create a C interface to calls Objective-C code from go are now go-gettable without producing and distributing .syso files. This change is analogous to the one in Go 1.2 made to support C++ built code.
This change doesn't support .mm files (Objective C++).
Also added support for these MFiles to go list's -json mode.
Fixes#6536.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/60590044
c:\src\go\pkg\obj\windows_amd64\libgc.a(lex.o): In function `catcher':
c:/src/go/src/cmd/gc/lex.c:181: undefined reference to `noted'
LGTM=0intro
R=0intro
CC=golang-codereviews
https://golang.org/cl/63270043
warning: src/cmd/gc/popt.c:700 format mismatch d VLONG, arg 4
warning: src/cmd/gc/popt.c:700 format mismatch d VLONG, arg 5
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/62910043
copyau1 was assuming that it could deduce the type of the
middle register p->reg from the type of the left or right
argument: in CMPF F1, F2, the p->reg==2 must be a D_FREG
because p->from is F1, and in CMP R1, R2, the p->reg==2 must
be a D_REG because p->from is R1.
This heuristic fails for CMP $0, R2, which was causing copyau1
not to recognize p->reg==2 as a reference to R2, which was
keeping it from properly renaming the register use when
substituting registers.
cmd/5c has the right approach: look at the opcode p->as to
decide the kind of register. It is unclear where 5g's copyau1
came from; perhaps it was an attempt to avoid expanding 5c's
a2type to include new instructions used only by 5g.
Copy a2type from cmd/5c, expand to include additional instructions,
and make it crash the compiler if asked about an instruction
it does not understand (avoid silent bugs in the future if new
instructions are added).
Should fix current arm build breakage.
While we're here, fix the print statements dumping the pred and
succ info in the asm listing to pass an int arg to %.4ud
(Prog.pc is a vlong now, due to the liblink merge).
TBR=ken2
CC=golang-codereviews
https://golang.org/cl/62730043
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
Second part of the solaris/amd64 linker changes: relocation and symbol table.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/61330043
The UNDEF instruction was listed in the instruction data as having the next instruction in the stream as its successor. This confused the optimizer into adding a load where it wasn't needed, in turn confusing the liveness analysis pass for GC bitmaps into thinking that the variable was live.
Fixes#7229.
LGTM=iant, rsc
R=golang-codereviews, bradfitz, iant, dave, rsc
CC=golang-codereviews
https://golang.org/cl/56910045
At present, when a package identifier is used outside of a selector expression, gc gives the error "use of package %S outside selector". However, in the selector expression x.f, the spec defines f as the selector. This change makes the error clearer.
Fixes#7133.
LGTM=rsc
R=golang-codereviews, rsc
CC=golang-codereviews
https://golang.org/cl/50060047
Fixes#7293.
Update #7261
The bsd ld(1) does not understand $ORIGIN and has restrictions on using -rpath when using clang(1), the default compiler on darwin.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/58480045
Fixes#7260.
Fix three broken tests in test.bash
The test for issue 4568 was confused by go $ACTION . producing a package root of "", avoiding this mode fixes the test but weakens the test.
The test for issue 4773 was broken on linux because math/Rand would fail to resolve as a package causing the test for duplicates to be skipped.
Finally, the last breakage was a small change in the error message.
Also, add test for foldDup.
LGTM=iant
R=iant, rsc
CC=golang-codereviews
https://golang.org/cl/61070044
rsc suggested that we split the whole linker changes into three parts.
This is the first one, mostly dealing with adding Hsolaris.
LGTM=iant
R=golang-codereviews, iant, dave
CC=golang-codereviews
https://golang.org/cl/54210050
This changes makes sgen and clearfat use unaligned instructions for
the trailing bytes, like the runtime memmove does, resulting in faster
code when manipulating types whose size is not a multiple of 8.
LGTM=khr
R=khr, iant, rsc
CC=golang-codereviews
https://golang.org/cl/51740044
Introduce two new environment variables, CC_FOR_TARGET and CXX_FOR_TARGET.
CC_FOR_TARGET defaults to CC and is used when compiling for GOARCH, while
CC remains for compiling for GOHOSTARCH.
CXX_FOR_TARGET defaults to CXX and is used when compiling C++ code for
GOARCH.
CGO_ENABLED defaults to disabled when cross compiling and has to be
explicitly enabled.
Update #4714
LGTM=minux.ma, iant
R=golang-codereviews, minux.ma, iant, rsc, dominik.honnef
CC=golang-codereviews
https://golang.org/cl/57100043
CL 56120043 fixed and cleaned up TLS on ARM after introducing liblink, but
left flag_shared broken. This CL restores the (unsupported) flag_shared
behaviour by simply rewriting access to $runtime.tlsgm(SB) with
runtime.tlsgm(SB), to compensate for the extra indirection when going from
the R_ARM_TLS_LE32 relocation to the R_ARM_TLS_IE32 relocation.
Also, remove unnecessary symbol lookup left after 56120043.
LGTM=iant
R=iant, rsc
CC=golang-codereviews
https://golang.org/cl/57000043
CL 56120043 fixed TLS handling on ARM after the introduction of
liblink but left older ARM processors broken.
Before liblink, the MRC instruction was replaced with a fallback
on older ARMs. CL 56120043 removed that, because the rewrite matched
bit patterns on the AWORD pseudo-instruction and could therefore change
unrelated AWORDs that happened to match.
This CL adds an AMRC instruction to encode both MRC and MCR previously
encoded as AWORDs. Then, in liblink, the AMRC instructions are either
rewritten to AWORD, or, on goarm < 7, replaced with a branch to the
fallback.
./all.bash completes successfully on an ARMv7 with either GOARM=7 or
GOARM=5. I have verified that the fallback is indeed present in both
runtime.save_gm and runtime.load_gm when GOARM=5 but not when GOARM=7.
If all goes well, this should fix the armv5 builders.
LGTM=iant
R=iant, rsc
CC=golang-codereviews
https://golang.org/cl/55540044
Array values are comparable if values of the array element type
are comparable.
Fixes#6526.
LGTM=khr
R=rsc, bradfitz, khr
CC=golang-codereviews
https://golang.org/cl/58580043
In external link mode the linker explicitly adds the string
constant "runtime/cgo". It adds the string constant using the
same symbol name as the compiler, but a different format. The
compiler assumes that the string data immediately follows the
string header, but the linker puts the two in different
sections. The result is bad string data when the compiler
sees "runtime/cgo" used as a string constant.
The compiler assumption is in datastring in [568]g/gobj.c.
The linker layout is in addstrdata in ld/data.c. The compiler
assumption is valid for string literals. The linker is not
creating a string literal, so its assumption is also valid.
There are a few ways to avoid this problem. This patch fixes
it by only doing the fake import of runtime/cgo if necessary,
and by only creating the string symbol if necessary.
Fixes#7234.
LGTM=dvyukov
R=golang-codereviews, dvyukov, bradfitz
CC=golang-codereviews
https://golang.org/cl/58410043
The code is copied from cmd/6g.
Empirically, all branch targets are nil in this code so
something is still wrong, but at least this stops 8g -S
from crashing.
Update #7178
LGTM=dave, iant
R=iant, dave
CC=golang-codereviews
https://golang.org/cl/58400043
Under some circumstances linking a test binary with gccgo can fail, because
the installed version of the library ends up before the version built for the
test on the linker command line.
This admittedly slightly hackish fix fixes this by putting the library archives
on the linker command line in the order that a pre-order depth first traversal
of the dependencies gives them, which has the side effect of always putting the
version of the library built for the test first.
Fixes#6768
LGTM=rsc
R=golang-codereviews, minux.ma, gobot, rsc, dave
CC=golang-codereviews
https://golang.org/cl/28050043
There is more zeroing than I would like right now -
temporaries used for the new map and channel runtime
calls need to be eliminated - but it will do for now.
This CL only has an effect if you are building with
GOEXPERIMENT=precisestack ./all.bash
(or make.bash). It costs about 5% in the overall time
spent in all.bash. That number will come down before
we make it on by default, but this should be enough for
Keith to try using the precise maps for copying stacks.
amd64 only (and it's not really great generated code).
TBR=khr, iant
CC=golang-codereviews
https://golang.org/cl/56430043
The addition of TLS to ARM rewrote the MRC instruction
differently depending on whether we were using internal
or external linking mode. That's clearly not okay, since we
don't know that during compilation, which is when we now
generate the code. Also, because the change did not introduce
a real MRC instruction but instead just macro-expanded it
in the assembler, liblink is rewriting a WORD instruction that
may actually be looking for that specific constant, which would
lead to very unexpected results. It was also using one value
that happened to be 8 where a different value that also
happened to be 8 belonged. So the code was correct for those
values but not correct in general, and very confusing.
Throw it all away.
Replace with the following. There is a linker-provided symbol
runtime.tlsgm with a value (address) set to the offset from the
hardware-provided TLS base register to the g and m storage.
Any reference to that name emits an appropriate TLS relocation
to be resolved by either the internal linker or the external linker,
depending on the link mode. The relocation has exactly the
semantics of the R_ARM_TLS_LE32 relocation, which is what
the external linker provides.
This symbol is only used in two routines, runtime.load_gm and
runtime.save_gm. In both cases it is now used like this:
MRC 15, 0, R0, C13, C0, 3 // fetch TLS base pointer
MOVW $runtime·tlsgm(SB), R2
ADD R2, R0 // now R0 points at thread-local g+m storage
It is likely that this change breaks the generation of shared libraries
on ARM, because the MOVW needs to be rewritten to use the global
offset table and a different relocation type. But let's get the supported
functionality working again before we worry about unsupported
functionality.
LGTM=dave, iant
R=iant, dave
CC=golang-codereviews
https://golang.org/cl/56120043
It implements parsing of the header and symbol table for both
32-bit and 64-bit Plan 9 binaries. The nm tool was updated to
use this package.
R=rsc, aram
CC=golang-codereviews
https://golang.org/cl/49970044
Now that liblink is compiled into the compilers and assemblers,
it must not refer to the "linkmode", since that is not known until
link time. This CL makes the ARM support no longer use linkmode,
which fixes a bug with cgo binaries that contain their own TLS
variables.
The x86 code must also remove linkmode; that is issue 7164.
Fixes#6992.
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/55160043
The escape analysis works by tracing assignment paths from
variables that start with pointer type, or addresses of variables
(addresses are always pointers). It does allow non-pointers
in the path, so that in this code it sees x's value escape into y:
var x *[10]int
y := (*int)(unsafe.Pointer(uintptr(unsafe.Pointer(x))+32))
It must allow uintptr in order to see through this kind of
"pointer arithmetic".
It also traces such values if they end up as uintptrs passed to
functions. This used to be important because packages like
encoding/gob passed around uintptrs holding real pointers.
The introduction of precise collection of stacks has forced
code to be more honest about which declared stack variables
hold pointers and which do not. In particular, the garbage
collector no longer sees pointers stored in uintptr variables.
Because of this, packages like encoding/gob have been fixed.
There is not much point in the escape analysis accepting
uintptrs as holding pointers at call boundaries if the garbage
collector does not.
Excluding uintptr-valued arguments brings the escape
analysis in line with the garbage collector and has the
useful side effect of making arguments to syscall.Syscall
not appear to escape.
That is, this CL should yield the same benefits as
CL 45930043 (rolled back in CL 53870043), but it does
so by making uintptrs less special, not more.
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/53940043
Vararg C calls present a problem for the GC because the
argument types are not derivable from the signature. Remove
them by passing pointers to channel elements instead of the
channel elements directly.
R=golang-codereviews, gobot, rsc, dvyukov
CC=golang-codereviews
https://golang.org/cl/53430043
The compiler change is an ugly hack.
We can do better.
««« original CL description
syscall: mark arguments to Syscall as noescape
Heap arguments to "async" syscalls will break when/if we have moving GC anyway.
With this change is must not break until moving GC, because a user must
reference the object in Go to preserve liveness. Otherwise the code is broken already.
Reduces number of leaked params from 125 to 36 on linux.
R=golang-codereviews, mikioh.mikioh, bradfitz
CC=cshapiro, golang-codereviews, khr, rsc
https://golang.org/cl/45930043
»»»
R=golang-codereviews, r
CC=bradfitz, dvyukov, golang-codereviews
https://golang.org/cl/53870043
Heap arguments to "async" syscalls will break when/if we have moving GC anyway.
With this change is must not break until moving GC, because a user must
reference the object in Go to preserve liveness. Otherwise the code is broken already.
Reduces number of leaked params from 125 to 36 on linux.
R=golang-codereviews, mikioh.mikioh, bradfitz
CC=cshapiro, golang-codereviews, khr, rsc
https://golang.org/cl/45930043
This CL makes the bitmaps a little more precise about variables
that have their address taken but for which the address does not
escape to the heap, so that the variables are kept in the stack frame
rather than allocated on the heap.
The code before this CL handled these variables by treating every
return statement as using every such variable and depending on
liveness analysis to essentially treat the variable as live during the
entire function. That approach has false positives and (worse) false
negatives. That is, it's both sloppy and buggy:
func f(b1, b2 bool) { // x live here! (sloppy)
if b2 {
print(0) // x live here! (sloppy)
return
}
var z **int
x := new(int)
*x = 42
z = &x
print(**z) // x live here (conservative)
if b2 {
print(1) // x live here (conservative)
return
}
for {
print(**z) // x not live here (buggy)
}
}
The first two liveness annotations (marked sloppy) are clearly
wrong: x cannot be live if it has not yet been declared.
The last liveness annotation (marked buggy) is also wrong:
x is live here as *z, but because there is no return statement
reachable from this point in the code, the analysis treats x as dead.
This CL changes the liveness calculation to mark such variables
live exactly at points in the code reachable from the variable
declaration. This keeps the conservative decisions but fixes
the sloppy and buggy ones.
The CL also detects ambiguously live variables, those that are
being marked live but may not actually have been initialized,
such as in this example:
func f(b1 bool) {
var z **int
if b1 {
x := new(int)
*x = 42
z = &x
} else {
y := new(int)
*y = 54
z = &y
}
print(**z) // x, y live here (conservative)
}
Since the print statement is reachable from the declaration of x,
x must conservatively be marked live. The same goes for y.
Although both x and y are marked live at the print statement,
clearly only one of them has been initialized. They are both
"ambiguously live".
These ambiguously live variables cause problems for garbage
collection: the collector cannot ignore them but also cannot
depend on them to be initialized to valid pointer values.
Ambiguously live variables do not come up too often in real code,
but recent changes to the way map and interface runtime functions
are invoked has created a large number of ambiguously live
compiler-generated temporary variables. The next CL will adjust
the analysis to understand these temporaries better, to make
ambiguously live variables fairly rare.
Once ambiguously live variables are rare enough, another CL will
introduce code at the beginning of a function to zero those
slots on the stack. At that point the garbage collector and the
stack copying routines will be able to depend on the guarantee that
if a slot is marked as live in a liveness bitmap, it is initialized.
R=khr
CC=golang-codereviews, iant
https://golang.org/cl/51810043
Replace the pack command, a C program, with a clean reimplementation in Go.
It does not need to reproduce the full feature set and it is no longer used by
the build chain, but has a role in looking inside archives created by the build
chain directly.
Since it's not in C, it is no longer build by dist, so remove it from cmd/dist and
make it a "tool" in cmd/go terminology.
Fixes#2705
R=rsc, dave, minux.ma, josharian
CC=golang-codereviews
https://golang.org/cl/52310044
Map iteration previously started from a random bucket, but walked each
bucket from the beginning. Now, iteration always starts from the first
bucket and walks each bucket starting at a random offset. For
performance, the random offset is selected at the start of iteration
and reused for each bucket.
Iteration over a map with 8 or fewer elements--a single bucket--will
now be non-deterministic. There will now be only 8 different possible
map iterations.
Significant benchmark changes, on my OS X laptop (rough but consistent):
benchmark old ns/op new ns/op delta
BenchmarkMapIter 128 121 -5.47%
BenchmarkMapIterEmpty 4.26 4.45 +4.46%
BenchmarkNewEmptyMap 114 111 -2.63%
Fixes#6719.
R=khr, bradfitz
CC=golang-codereviews
https://golang.org/cl/47370043
Having these flags misleads people into thinking they're acceptable
for code that "must be gofmt'd".
If an organization wishes to use gofmt internally with
different settings, they can fork gofmt trivially. But "gofmt"
as used by the community with open source Go code should not
support these old knobs.
Also removes the -comments flag.
Fixes#7101
R=r, gri
CC=golang-codereviews
https://golang.org/cl/52170043
For historical reasons, temp was returning a copy
of the created Node*, not the original Node*.
This meant that if analysis recorded information in the
returned node (for example, n->addrtaken = 1), the
analysis would not show up on the original Node*, the
one kept in fn->dcl and consulted during liveness
bitmap creation.
Correct this, and watch for it when setting addrtaken.
Fixes#7083.
R=khr, dave, minux.ma
CC=golang-codereviews
https://golang.org/cl/51010045
The golden file for link.hello.darwin.amd64
was a little ahead of the checked-in code.
R=iant
TBR=iant
CC=golang-codereviews
https://golang.org/cl/51870043
Related changes included in this CL:
- Add explicit start symbol to Prog.
- Add omitRuntime bool to Prog.
- Introduce p.Packages[""] to hold automatic symbols
- Add SymOrder to Prog to preserve symbol order.
- Add layout test (and fix bug that was putting everything in text section).
R=iant
CC=golang-codereviews
https://golang.org/cl/51260045
The hex dumps will diff better, and I hope they will avoid
a repeat of http://bugs.debian.org/716853.
The CL will probably show the testdata diffs as "binary",
but in fact the binary versions are being replaced by
textual hex dumps (output of hexdump -C).
R=iant
CC=golang-codereviews
https://golang.org/cl/51000044
Nodes of goto statements were corrupted when written
to export data.
Fixes#7023.
R=rsc, dave, minux.ma
CC=golang-codereviews
https://golang.org/cl/46190043
Everything was doing this already with #defines.
Do it right.
R=golang-codereviews, jsing, 0intro, iant
CC=golang-codereviews
https://golang.org/cl/49090043
When printing the size, we often want to sort on that key.
Because it's used when looking for large things, make the
sort go from largest to smallest.
Perfect recreation of CL 45150044, which was lost to some blunder.
R=golang-codereviews, gobot, rsc
CC=golang-codereviews
https://golang.org/cl/48500044
When recompiling a package whose basename is the name of a standard
package for testing with gccgo, a .o file with the basename of the
package being tested was being placed in the _test/ directory where the
compilation of the test binary then found it when looking for the
standard library package.
This change puts the object files in a separate directory.
Fixes#6793
R=golang-codereviews, dave, gobot, rsc, iant
CC=golang-codereviews
https://golang.org/cl/27650045
This change adds solaris to the list of supported operating
systems and allows cmd/dist to be built on Solaris.
This CL has to come first because we want the tools to ignore
solaris-specific files until the whole port is integrated.
R=golang-codereviews, jsing, rsc, minux.ma
CC=golang-codereviews
https://golang.org/cl/35900045
[]byte("string") was simplifying to
[]byte{0: 0x73, 1: 0x74, 2: 0x72, 3: 0x69, 4: 0x6e, 5: 0x67},
but that latter form takes up much more memory in the compiler.
Preserve the string form and recognize it to turn global variables
initialized this way into linker-initialized data.
Reduces the compiler memory footprint for a large []byte initialized
this way from approximately 10 kB/B to under 100 B/B.
See also issue 6643.
R=golang-codereviews, r, iant, oleku.konko, dave, gobot, bradfitz
CC=golang-codereviews
https://golang.org/cl/15930045
This change fixes a serious performance regression
with reflect.Value growing to 4 words instead of 3.
The json benchmark was ~50% slower, with this change
it is ~5% slower (and the binary is 0.5% larger).
Longer term, we probably need to rethink our copy
generation. Using REP is really expensive time-wise.
But inlining the copy grows the binary.
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/44990043
As much as 7x speedup on some programs, cuts all.bash time by 20%.
Change splicebefore function from O(n) to O(1).
The approach was suggested by Carl during the code's review
but apparently did not make it into the tree.
It makes a huge difference on huge programs.
Make twobitwalktype1 slightly faster by using & instead of %.
Really it needs to be cached; left a note to that effect.
(Not a complete fix, hence the ½.)
big.go (output of test/chan/select5.go)
47.53u 0.50s 48.14r before this CL
7.09u 0.47s 7.59r with splicebefore change (6.7x speedup)
6.15u 0.42s 6.59r with twobitwalktype1 change (1.15x speedup; total 7.7x)
slow.go (variant of program in go.text, by mpvl)
77.75u 2.11s 80.03r before this CL
24.40u 1.97s 26.44r with splicebefore change (3.2x speedup)
18.12u 2.19s 20.38r with twobitwalktype1 change (1.35x speedup; total 4.3x)
test/run
150.63u 49.57s 81.08r before this CL
88.01u 45.60s 46.65r after this CL (1.7x speedup)
all.bash
369.70u 115.64s 256.21r before this CL
298.52u 110.35s 214.67r after this CL (1.24x speedup)
The test programs are at
https://rsc.googlecode.com/hg/testdata/big.go (36k lines, 276kB)
https://rsc.googlecode.com/hg/testdata/slow.go (7k lines, 352kB)
R=golang-codereviews, gobot, r
CC=cshapiro, golang-codereviews
https://golang.org/cl/43210045
Eventually we will want to bypass DATA for everything,
but the relocations are not standardized well enough across
architectures to make that possible.
This did not help as much as I expected, but it is definitely better.
It shaves maybe 1-2% off all.bash depending on how much you
trust the timings of a single run:
Before: 241.139r 362.702u 112.967s
After: 234.339r 359.623u 111.045s
R=golang-codereviews, gobot, r, iant
CC=golang-codereviews
https://golang.org/cl/44650043
These no longer work; removing them makes other refactoring easier.
The code for pack P being deleted in this CL does not work either.
I created issue 6989 to track restoring this functionality (probably not
until pack is written in Go).
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/44300043
The code is all about tags, and the cmd/go documentation
said to look in the go/build documentation for information
about tags, but the documentation said nothing about tags,
only build constraints. Make things clearer.
R=golang-dev, adg, rsc
CC=golang-dev
https://golang.org/cl/44100043
Make hostobj work on OpenBSD 5.3/5.4/-current - these have PIE
enabled by default and linking fails since the Go linker generates
objects that are neither PIC nor PIE.
Fixes#5067
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7572049
warning: src/cmd/6g/reg.c:671 format mismatch d VLONG, arg 4
warning: src/cmd/gc/pgen.c:230 set and not used: oldstksize
warning: src/cmd/gc/plive.c:877 format mismatch lx UVLONG, arg 2
warning: src/cmd/gc/walk.c:2878 set and not used: cbv
warning: src/cmd/gc/walk.c:2885 set and not used: hbv
warning: src/cmd/ld/data.c:198 format mismatch s IND FUNC(IND CHAR) INT, arg 2
warning: src/cmd/ld/data.c:230 format mismatch s IND FUNC(IND CHAR) INT, arg 2
warning: src/cmd/ld/dwarf.c:1517 set and not used: pc
warning: src/cmd/ld/elf.c:1507 format mismatch d VLONG, arg 2
warning: src/cmd/ld/ldmacho.c:509 set and not used: dsymtab
R=golang-dev, gobot, rsc
CC=golang-dev
https://golang.org/cl/36740045
warning: src/libmach/sym.c:1861 non-interruptable temporary
warning: src/cmd/8l/../ld/pcln.c:29 set and not used: p
R=golang-dev, gobot, rsc
CC=golang-dev
https://golang.org/cl/40500043
