Rémy Oudompheng [Fri, 2 Nov 2012 06:50:59 +0000 (07:50 +0100)]
cmd/5g, cmd/6g: fix out of registers with array indexing.
Compiling expressions like:
s[s[s[s[s[s[s[s[s[s[s[s[i]]]]]]]]]]]]
make 5g and 6g run out of registers. Such expressions can arise
if a slice is used to represent a permutation and the user wants
to iterate it.
This is due to the usual problem of allocating registers before
going down the expression tree, instead of allocating them in a
postfix way.
The functions cgenr and agenr (that generate a value to a newly
allocated register instead of an existing location), are either
introduced or modified when they already existed to allocate
the new register as late as possible, and sudoaddable is disabled
for OINDEX nodes so that igen/agenr is used instead.
Russ Cox [Fri, 2 Nov 2012 04:17:21 +0000 (00:17 -0400)]
cmd/gc, cmd/ld: struct field tracking
This is an experiment in static analysis of Go programs
to understand which struct fields a program might use.
It is not part of the Go language specification, it must
be enabled explicitly when building the toolchain,
and it may be removed at any time.
After building the toolchain with GOEXPERIMENT=fieldtrack,
a specific field can be marked for tracking by including
`go:"track"` in the field tag:
package pkg
type T struct {
F int `go:"track"`
G int // untracked
}
To simplify usage, only named struct types can have
tracked fields, and only exported fields can be tracked.
The implementation works by making each function begin
with a sequence of no-op USEFIELD instructions declaring
which tracked fields are accessed by a specific function.
After the linker's dead code elimination removes unused
functions, the fields referred to by the remaining
USEFIELD instructions are the ones reported as used by
the binary.
The -k option to the linker specifies the fully qualified
symbol name (such as my/pkg.list) of a string variable that
should be initialized with the field tracking information
for the program. The field tracking string is a sequence
of lines, each terminated by a \n and describing a single
tracked field referred to by the program. Each line is made
up of one or more tab-separated fields. The first field is
the name of the tracked field, fully qualified, as in
"my/pkg.T.F". Subsequent fields give a shortest path of
reverse references from that field to a global variable or
function, corresponding to one way in which the program
might reach that field.
A common source of false positives in field tracking is
types with large method sets, because a reference to the
type descriptor carries with it references to all methods.
To address this problem, the CL also introduces a comment
annotation
//go:nointerface
that marks an upcoming method declaration as unavailable
for use in satisfying interfaces, both statically and
dynamically. Such a method is also invisible to package
reflect.
Again, all of this is disabled by default. It only turns on
if you have GOEXPERIMENT=fieldtrack set during make.bash.
R=iant, ken
CC=golang-dev
https://golang.org/cl/6749064
Dmitriy Vyukov [Thu, 1 Nov 2012 18:56:04 +0000 (22:56 +0400)]
cmd/gc: racewalk: fix a bunch of minor issues
1. Prepend racefuncenter() to fn->enter -- fn->enter can contain new() calls,
and we want them to be in the scope of the function.
2. Dump fn->enter and fn->exit.
3. Add TODO that OTYPESW expression can contain interesting memory accesses.
4. Ignore only _ names instead of all names starting with _.
Robert Griesemer [Thu, 1 Nov 2012 18:23:27 +0000 (11:23 -0700)]
exp/types/staging: filling in more blanks
- simplified assignment checking by removing duplicate code
- implemented field lookup (methods, structs, embedded fields)
- importing methods (not just parsing them)
- type-checking functions and methods
- typechecking more statements (inc/dec, select, return)
- tracing support for easier debugging
- handling nil more correctly (comparisons)
- initial support for [...]T{} arrays
- initial support for method expressions
- lots of bug fixes
All packages under pkg/go as well as pkg/exp/types typecheck
now with pkg/exp/gotype applied to them; i.e., a significant
amount of typechecking works now (several statements are not
implemented yet, but handling statements is almost trivial in
comparison with typechecking expressions).
Ian Lance Taylor [Thu, 1 Nov 2012 18:13:50 +0000 (11:13 -0700)]
cmd/go: fixes to gccgo support
* Use -fgo-pkgpath and -gccgopkgpath rather than -fgo-prefix
and -gccgoprefix.
* Define GOPKGPATH when compiling .c or .s files for gccgo.
* Use -fgo-relative-import-path.
* Produce .o files for gccgo, not .[568] files.
* Pass -E when linking if using cgo.
Dmitriy Vyukov [Thu, 1 Nov 2012 18:11:12 +0000 (22:11 +0400)]
cmd/gc: racewalk: fix instrumentation of ninit lists
The idea is to (1) process ninit of all nodes,
and (2) put instrumentation of ninit into the nodes themselves (not the top-level statement ninit).
Fixes #4304.
Robert Griesemer [Thu, 1 Nov 2012 17:13:48 +0000 (10:13 -0700)]
spec: clarify returns, defer statements, and panics
This is an attempt at making the interaction between
these three constructs clearer. Specifically:
- return statements terminate a function, execute deferred
functions, return to the caller, and then execution
continues after the call
- panic calls terminate a function, execute deferred
functions, return to the caller, and then re-panic
- deferred functions are executed before a function _returns_
to its caller
The hope is that with this change it becomes clear when a
deferred function is executed (when a function returns),
and when it is not (when a program exits).
Nigel Tao [Thu, 1 Nov 2012 00:46:06 +0000 (11:46 +1100)]
image/png: degrade gracefully for palette index values that aren't
defined by the PLTE chunk. Such pixels decode to opaque black,
which matches what libpng does.
Fixes #4319.
On my reading, the PNG spec isn't clear whether palette index values
outside of those defined by the PLTE chunk is an error, and if not,
what to do.
Libpng 1.5.3 falls back to opaque black. png_set_PLTE says:
/* Changed in libpng-1.2.1 to allocate PNG_MAX_PALETTE_LENGTH instead
* of num_palette entries, in case of an invalid PNG file that has
* too-large sample values.
*/
png_ptr->palette = (png_colorp)png_calloc(png_ptr,
PNG_MAX_PALETTE_LENGTH * png_sizeof(png_color));
Marcel van Lohuizen [Wed, 31 Oct 2012 13:28:44 +0000 (14:28 +0100)]
exp/locale/collate: implementation of tailorings and table generation.
Tailorings are represented by removing and reinserting entries from a linked list.
After all tailorings are done, missing weights are computed and verified.
This implementation assumes that entries that are used in expansions are not
reinserted at a later point. This considerably simplifies the implementation.
Marcel van Lohuizen [Wed, 31 Oct 2012 13:28:18 +0000 (14:28 +0100)]
exp/locale/collate: removed weights struct to allow for faster and easier
incremental comparisons. Instead, processing is now done directly on colElems.
As a result, the size of the weights array is now reduced by 75%.
Details:
- Primary value of type 1 colElem is shifted by 1 bit so that primaries
of all types can be compared without shifting.
- Quaternary values are now stored in the colElem itself. This is possible
as quaternary values other than 0 or maxQuaternary are only needed when other
values are ignored.
- Simplified processWeights by removing cases that are needed for ICU but not
for us (our CJK primary values fit in a single value).
Alex Brainman [Tue, 30 Oct 2012 23:24:37 +0000 (10:24 +1100)]
net: fix connection resets when closed on windows
It is common to close network connection while another goroutine is
blocked reading on another goroutine. This sequence corresponds to
windows calls to WSARecv to start io, followed by GetQueuedCompletionStatus
that blocks until io completes, and, finally, closesocket called from
another thread. We were expecting that closesocket would unblock
GetQueuedCompletionStatus, and it does, but not always
(http://code.google.com/p/go/issues/detail?id=4170#c5). Also that sequence
results in connection is being reset.
This CL inserts CancelIo between GetQueuedCompletionStatus and closesocket,
and waits for both WSARecv and GetQueuedCompletionStatus to complete before
proceeding to closesocket. This seems to fix both connection resets and
issue 4170. It also makes windows code behave similar to unix version.
Unfortunately, CancelIo needs to be called on the same thread as WSARecv.
So we have to employ strategy we use for connections with deadlines to
every connection now. It means, there are 2 unavoidable thread switches
for every io. Some newer versions of windows have new CancelIoEx api that
doesn't have these drawbacks, and this CL uses this capability when available.
As time goes by, we should have less of CancelIo and more of CancelIoEx
systems. Computers with CancelIoEx are also not affected by issue 4195 anymore.
Shenghou Ma [Tue, 30 Oct 2012 15:58:43 +0000 (23:58 +0800)]
cmd/ld: handle weak symbols
compiler_rt introduces a weak and hidden symbol compilerrt_abort_impl
into our pre-linked _all.o object, we have to handle it.
Fixes #4273.
R=iant, rsc, r
CC=golang-dev
https://golang.org/cl/6783050
Nigel Tao [Tue, 30 Oct 2012 00:10:08 +0000 (11:10 +1100)]
image/jpeg: change block from [64]int to [64]int32.
On 6g/linux:
benchmark old ns/op new ns/op delta
BenchmarkFDCT 4606 4241 -7.92%
BenchmarkIDCT 4187 3923 -6.31%
BenchmarkDecodeBaseline 31548643170224 +0.49%
BenchmarkDecodeProgressive 40728124017132 -1.37%
BenchmarkEncode 3940692034596760 -12.21%
Stack requirements before (from 'go tool 6g -S'):
(scan.go:37) TEXT (*decoder).processSOS+0(SB),$1352-32
(writer.go:448) TEXT (*encoder).writeSOS+0(SB),$5344-24
after:
(scan.go:37) TEXT (*decoder).processSOS+0(SB),$1064-32
(writer.go:448) TEXT (*encoder).writeSOS+0(SB),$2520-24
Also, in encoder.writeSOS, re-use the yBlock scratch buffer for Cb and
Cr. This reduces the stack requirement slightly, but also avoids an
unlucky coincidence where a BenchmarkEncode stack split lands between
encoder.writeByte and bufio.Writer.WriteByte, which occurs very often
during Huffman encoding and is otherwise disasterous for the final
benchmark number. FWIW, the yBlock re-use *without* the s/int/int32/
change does not have a noticable effect on the benchmarks.
Pawel Szczur [Mon, 29 Oct 2012 16:56:31 +0000 (17:56 +0100)]
net/http/client.go: fix cookie handling on (*Client) Do()
Fix the problem with no cookie handling when sending
other than GET or HEAD request through
(*Client) Do(*Request) (*Resposne, error).
https://code.google.com/p/go/issues/detail?id=3985
Adds a function (*Client) send(*Request) (*Reponse, error):
- sets cookies from CookieJar to request,
- sends request
- parses a reply cookies and updates CookieJar
Adam Langley [Mon, 29 Oct 2012 15:16:05 +0000 (11:16 -0400)]
encoding/asn1: don't convert UTCTime to UTC.
Previously we converted a time to UTC *and* serialized the timezone of
the original time. With this change, we serialize a UTCTime in the
original timezone.
Luuk van Dijk [Mon, 29 Oct 2012 12:55:27 +0000 (13:55 +0100)]
cmd/gc: inlining functions with local variables
- make sure dclcontext == PAUTO only in function bodies
- introduce PDISCARD to discard declarations in bodies of repeated imports
- skip printing initializing OAS'es in export mode, assuming they only occur after ODCL's
- remove ODCL and the initializing OAS from inl.c:ishairy
- fix confused use of ->typecheck in typecheckinl: it's about the ->inl, not about the fn.
- debuging aids: print ntype on ONAMEs too and -Emm instead of -Ell.
Luuk van Dijk [Mon, 29 Oct 2012 12:38:21 +0000 (13:38 +0100)]
cmd/gc: escape analysis to track flow of in to out parameters.
includes step 0: synthesize outparams, from 6600044
includes step 1,2: give outparams loopdepth 0 and verify unchanged results
generate esc:$mask tags, but still tie to sink if a param has mask != 0
from 6610054
adds final steps:
- have esccall generate n->escretval, a list of nodes the function results flow to
- use these in esccall and ORETURN/OAS2FUNC/and f(g())
- only tie parameters to sink if tag is absent, otherwise according to mask, tie them to escretval
David Symonds [Mon, 29 Oct 2012 11:03:58 +0000 (22:03 +1100)]
misc/dashboard/codereview: only accept "NOT LGTM" on the first line of a message.
Too many people quote entire emails and put their reply at the top ("top posting"),
so we shouldn't recognise review commands anywhere in the review text.
Ian Lance Taylor [Fri, 26 Oct 2012 17:31:03 +0000 (10:31 -0700)]
syscall: fix creds_test to reliably close os.File
Before this patch the test would close the file descriptor but
not the os.File. When the os.File was GC'ed, the finalizer
would close the file descriptor again. That would cause
problems if the same file descriptor were returned by a later
call to open in another test.
On my system:
> GOGC=30 go test
--- FAIL: TestPassFD (0.04 seconds)
passfd_test.go:62: FileConn: dup: bad file descriptor
FAIL
Dave Cheney [Fri, 26 Oct 2012 08:41:21 +0000 (19:41 +1100)]
net: avoid allocation in setAddr
setAddr was showing up in profiles due to string concatenation construction the os.File name field. netFD.sysfile's Name() is never used, except in dup() so I believe it is safe to avoid this allocation.
Marcel van Lohuizen [Thu, 25 Oct 2012 11:02:31 +0000 (13:02 +0200)]
exp/locale/collate: slightly changed collation elements:
- Allow secondary values below the default value in second form. This is
to support before tags for secondary values, as used by Chinese.
- Eliminate collation elements that are guaranteed to be immaterial
after a weight increment.
Luuk van Dijk [Mon, 22 Oct 2012 08:18:17 +0000 (10:18 +0200)]
cmd/gc: escape analysis to track flow of in to out parameters.
includes step 0: synthesize outparams, from 6600044
step 1: give outparams loopdepth 0 and verify unchanged results
step 2: generate esc:$mask tags, but still tie to sink if a param has mask != 0
next step: use in esccall (and ORETURN with implicit OAS2FUNC) to avoid tying to sink