Ian Lance Taylor [Fri, 10 Jul 2015 22:28:01 +0000 (15:28 -0700)]
runtime: on unexpected netpoll error, throw instead of looping
The current code prints an error message and then tries to carry on.
This is not helpful for Go users: they see a message that means
nothing and that they can do nothing about. In the only known case of
this message, in issue 11498, the best guess is that the netpoll code
went into an infinite loop. Instead of doing that, crash the program.
Keith Randall [Tue, 1 Sep 2015 19:53:15 +0000 (12:53 -0700)]
runtime: fix aeshash of empty string
Aeshash currently computes the hash of the empty string as
hash("", seed) = seed. This is bad because the hash of a compound
object with empty strings in it doesn't include information about
where those empty strings were. For instance [2]string{"", "foo"}
and [2]string{"foo", ""} might get the same hash.
Fix this by returning a scrambled seed instead of the seed itself.
With this fix, we can remove the scrambling done by the generated
array hash routines.
The test also rejects hash("", seed) = 0, if we ever thought
it would be a good idea to try that.
Rob Pike [Mon, 14 Sep 2015 18:27:20 +0000 (11:27 -0700)]
text/template: verify that names in FuncMap are valid identifiers
There was no verification in Funcs that the map had valid names,
which meant that the error could only be caught when parsing
the template that tried to use them. Fix this by validating the names
in Funcs and panicking before parsing if there is a bad name.
This is arguably an API change, since it didn't trigger a panic
before, but Funcs did already panic if the function itself was no
good, so I argue it's an acceptable change to add more sanity
checks.
Fixes #9685.
Change-Id: Iabf1d0602c49d830f3ed71ca1ccc7eb9a5521ff5
Reviewed-on: https://go-review.googlesource.com/14562 Reviewed-by: Andrew Gerrand <adg@golang.org>
Cleaning along the way:
-convert variable types from int to bool
-remove unnecessary functions
-remove unnecessary type conversion
-remove unnecessary variable declarations
-transform struct{string,string} with lookup to map[string]string
This change passes go build -toolexec 'toolstash -cmp' -a std.
Change-Id: I259728fe4afd7f23b67f08fab856ce0abee57b21
Reviewed-on: https://go-review.googlesource.com/14435 Reviewed-by: Ian Lance Taylor <iant@golang.org>
net: remove named parameters in Listener.Accept doc signature
They added no value.
Change-Id: I9e690379d2dfd983266de0ea5231f2b57c8b1517
Reviewed-on: https://go-review.googlesource.com/14568 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Dave Cheney [Fri, 7 Aug 2015 01:15:54 +0000 (11:15 +1000)]
cmd/go: skip external tests on linux/arm
CL 13166 skipped external tests on freebsd/arm with the rationale
that the cmd/go tests are not architecture dependent.
This CL does the same for linux/arm to help linux/arm users who are
building Go on platforms like the Raspberry Pi where ./all.bash
frequently times out due to a lack of resources.
Change-Id: Iae1a25b63b74200da3f1b5637da0fa5c2dceeb83
Reviewed-on: https://go-review.googlesource.com/13342 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Alex Brainman [Thu, 3 Sep 2015 07:48:21 +0000 (17:48 +1000)]
runtime: provide room for first 4 syscall parameters in windows usleep2
Windows amd64 requires all syscall callers to provide room for first
4 parameters on stack. We do that for all our syscalls, except inside
of usleep2. In https://codereview.appspot.com/7563043#msg3 rsc says:
"We don't need the stack alignment and first 4 parameters on amd64
because it's just a system call, not an ordinary function call."
He seems to be wrong on both counts. But alignment is already fixed.
Fix parameter space now too.
Ian Lance Taylor [Fri, 4 Sep 2015 17:58:42 +0000 (10:58 -0700)]
runtime: unblock special glibc signals on each thread
Glibc uses some special signals for special thread operations. These
signals will be used in programs that use cgo and invoke certain glibc
functions, such as setgid. In order for this to work, these signals
need to not be masked by any thread. Before this change, they were
being masked by programs that used os/signal.Notify, because it
carefully masks all non-thread-specific signals in all threads so that a
dedicated thread will collect and report those signals (see ensureSigM
in signal1_unix.go).
This change adds the two glibc special signals to the set of signals
that are unmasked in each thread.
Fixes #12498.
Change-Id: I797d71a099a2169c186f024185d44a2e1972d4ad
Reviewed-on: https://go-review.googlesource.com/14297 Reviewed-by: David Crawshaw <crawshaw@golang.org>
This is a cleanup following cc8f544, which was a minimal change to fix
issue #11617. This consolidates the two places in mSpan_Sweep that
update sweepgen. Previously this was necessary because sweepgen must
be updated before freeing the span, but we freed large spans early.
Now we free large spans later, so there's no need to duplicate the
sweepgen update. This also means large spans can take advantage of the
sweepgen sanity checking performed for other spans.
Change-Id: I23b79dbd9ec81d08575cd307cdc0fa6b20831768
Reviewed-on: https://go-review.googlesource.com/12451 Reviewed-by: Rick Hudson <rlh@golang.org>
Austin Clements [Tue, 4 Aug 2015 14:45:29 +0000 (10:45 -0400)]
runtime: split marking of span roots into 128 subtasks
Marking of span roots can represent a significant fraction of the time
spent in mark termination. Simply traversing the span list takes about
1ms per GB of heap and if there are a large number of finalizers (for
example, for network connections), it may take much longer.
Improve the situation by splitting the span scan into 128 subtasks
that can be executed in parallel and load balanced by the markroots
parallel for. This lets the GC balance this job across the Ps.
A better solution is to do this during concurrent mark, or to improve
it algorithmically, but this is a simple change with a lot of bang for
the buck.
This was suggested by Rhys Hiltner.
Updates #11485.
Change-Id: I8b281adf0ba827064e154a1b6cc32d4d8031c03c
Reviewed-on: https://go-review.googlesource.com/13112 Reviewed-by: Keith Randall <khr@golang.org>
Austin Clements [Thu, 13 Aug 2015 03:39:10 +0000 (23:39 -0400)]
runtime: fix hashing of trace stacks
The call to hash the trace stack reversed the "seed" and "size"
arguments to memhash and, hence, always called memhash with a 0 size,
which dutifully returned a hash value that depended only on the number
of PCs in the stack and not their values. As a result, all stacks were
put in to a very subset of the 8,192 buckets.
Fix this by passing these arguments in the correct order.
Dave Cheney [Thu, 20 Aug 2015 03:46:19 +0000 (13:46 +1000)]
runtime: reduce pthread stack size in TestCgoCallbackGC
Fixes #11959
This test runs 100 concurrent callbacks from C to Go consuming 100
operating system threads, which at 8mb a piece (the default on linux/arm)
would reserve over 800mb of address space. This would frequently
cause the test to fail on platforms with ~1gb of ram, such as the
raspberry pi.
This change reduces the thread stack allocation to 256kb, a number picked
at random, but at 1/32th the previous size, should allow the test to
pass successfully on all platforms.
Change-Id: I8b8bbab30ea7b2972b3269a6ff91e6fe5bc717af
Reviewed-on: https://go-review.googlesource.com/13731
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Martin Capitanio <capnm9@gmail.com> Reviewed-by: Minux Ma <minux@golang.org>
Dave Cheney [Fri, 11 Sep 2015 14:10:42 +0000 (00:10 +1000)]
cmd/compile/internal/gc: avoid allocation in bnum
Although bnum was being called with a Bits value, a limitation
of the escape analyser (golang/go#12588) meant that taking the
address of the Bits.b array in the range statement caused the
formal parameter to escape to the heap.
Passing the a pointer to a Bits, as with all the other Bits helper
methods avoids the allocation.
Rob Pike [Thu, 10 Sep 2015 22:48:23 +0000 (15:48 -0700)]
cmd/asm: fix some fuzz bugs
One (12466) was an actual logic error, backing up when there was
nothing there. The others were due to continuing to process an
instruction when it cannot work.
Methodically stop assembling an instruction when it's not going to
succeed.
Fixes #12466.
Fixes #12467.
Fixes #12468.
Change-Id: I88c568f2b9c1a8408043b2ac5a78f5e2ffd62abd
Reviewed-on: https://go-review.googlesource.com/14498 Reviewed-by: Andrew Gerrand <adg@golang.org>
alexander demakin [Thu, 10 Sep 2015 16:43:20 +0000 (19:43 +0300)]
archive/zip: fixes unexpected EOF when reading archive
If comment of the archive contains data which looks like
a zip64 directory, the comment is parsed as an
actual directory header.
Commit adds some additional checks similar to the checks
in minizip library.
Fixes #12449
Change-Id: Ia0fc950e47b9c39f77d88401b9ca30100ca7c808
Reviewed-on: https://go-review.googlesource.com/14433
Run-TryBot: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Andrew Gerrand <adg@golang.org>
It was correct for an early version of the CL which introduced the
type, but later versions of the CL changed the behavior without
updating the documentation.
Fixes #12568
Change-Id: Ia4090a02ba122e9f8317ed86c4c9839ae2c539e0
Reviewed-on: https://go-review.googlesource.com/14496 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Rob Pike [Thu, 10 Sep 2015 20:41:03 +0000 (13:41 -0700)]
fmt: allow any type in a format's width argument
The construction
fmt.Printf("%*d", n, 4)
reads the argument n as a width specifier to use when printing 4.
Until now, only strict int type was accepted here and it couldn't
be fixed because the fix, using reflection, broke escape analysis
and added an extra allocation in every Printf call, even those that
do not use this feature.
The compiler has been fixed, although I am not sure when exactly,
so let's fix Printf and then write
Fixes #10732.
Change-Id: I79cf0c4fadd876265aa39d3cb62867247b36ab65
Reviewed-on: https://go-review.googlesource.com/14491 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Rob Pike [Mon, 31 Aug 2015 22:45:47 +0000 (15:45 -0700)]
time: allow any one- or two-digit day of the month when parsing.
In Parse, one can now say Feb 31 or even Feb 99. This is easy
to explain, consistent with time.Date, and even maybe useful.
Fixes #12333.
Fixes #7268. (By disagreeing with it.)
Change-Id: I7b95c842528bed66933681c8b9cc00640fccfcb4
Reviewed-on: https://go-review.googlesource.com/14123 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Michael Hudson-Doyle [Tue, 1 Sep 2015 22:35:54 +0000 (10:35 +1200)]
cmd/internal/obj, cmd/link, runtime: a saner model for TLS on arm
this leaves lots of cruft behind, will delete that soon
Change-Id: I12d6b6192f89bcdd89b2b0873774bd3458373b8a
Reviewed-on: https://go-review.googlesource.com/14196 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Dave Cheney [Thu, 10 Sep 2015 05:50:47 +0000 (15:50 +1000)]
cmd/go: use RawToken to parse remote package metadata
CL 14315 broke the tests for parsing loosely formed remote package
metadata. Switch the parsing to use RawToken to recover the previous
behaviour that Token provided.
It could be argued that the parser should be stricter, but as remote
metadata has been readable with the parser for several years, it is
safer to change the parser to continue to accept the samples provided
in the test cases.
Change-Id: I2a3ba1757d3cff53b1a1c4386276955bb46cf8cd
Reviewed-on: https://go-review.googlesource.com/14482 Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org> Reviewed-by: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Dave Cheney [Sun, 6 Sep 2015 23:59:43 +0000 (09:59 +1000)]
cmd/compile: convert typecheckdefstack to []*Node
This one of a set of changes to make the transition away from NodeList
easier by removing cases in which NodeList doesn't act semi-trivially like a
[]*Node.
This CL was originally prepared by Josh Bleecher Snyder <josharian@gmail.com>.
This change passes go build -toolexec 'toolstash -cmp' -a std.
Shenghou Ma [Thu, 3 Sep 2015 23:15:26 +0000 (19:15 -0400)]
hash/*: document the byte order used by the Sum methods
Fixes #12350.
Change-Id: I3dcb0e2190c11f83f15fb07cc637fead54f734f7
Reviewed-on: https://go-review.googlesource.com/14275 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Robert Stepanek [Sat, 5 Sep 2015 14:06:43 +0000 (16:06 +0200)]
encoding/xml: Return SyntaxError for unmatched root start elements.
Currently, the xml.Decoder's Token routine returns successfully for
XML input that does not properly close root start elements (and any
unclosed descendants). For example, all the following inputs
<root>
<root><foo>
<root><foo></foo>
cause Token to return with nil and io.EOF, indicating a successful
parse.
This change fixes that. It leaves the semantics of RawToken intact.
Fixes #11405
Change-Id: I6f1328c410cf41e17de0a93cf357a69f12c2a9f7
Reviewed-on: https://go-review.googlesource.com/14315 Reviewed-by: Nigel Tao <nigeltao@golang.org>
The previous automated updates only added missing entries for commits
since Go 1.4, with the assumption that we were caught up on things
prior to that. (Initially motivated by the existence of junk email
address jokes in the early git history, which I initially didn't want
to whitelist)
But it turns out we were missing lots of stuff, at least for subrepos
prior to N months ago.
This is an update with all subrepos updated, with no date
restrictions.
Change-Id: I2b5580ae4f89ae9ba7eaa336cc54ce6d606c5379
Reviewed-on: https://go-review.googlesource.com/14409 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Keith Randall [Mon, 8 Jun 2015 15:42:28 +0000 (08:42 -0700)]
runtime: on map update, don't overwrite key if we don't need to.
Keep track of which types of keys need an update and which don't.
Strings need an update because the new key might pin a smaller backing store.
Floats need an update because it might be +0/-0.
Interfaces need an update because they may contain strings or floats.
In support of the changes required for #8609, it was suggested that
syscall.getwd() be updated to work on Solaris first since the runtime
uses it and today it's unimplemented.
Keith Randall [Tue, 8 Sep 2015 20:41:51 +0000 (13:41 -0700)]
cmd/compile/internal/gc: handle weird map literals in key dedup
We compute whether two keys k1 and k2 in a map literal are duplicates by
constructing the expression OEQ(k1, k2) and calling the constant
expression evaluator on that expression, then extracting the boolean
result.
Unfortunately, the constant expression evaluator can fail for various
reasons. I'm not really sure why it is dying in the case of 12536, but
to be safe we should use the result only if we get a constant back (if
we get a constant back, it must be boolean). This probably isn't a
permanent fix, but it should be good enough for 1.5.2.
A permanent fix would be to ensure that the constant expression
evaluator can always work for map literal keys, and if not the compiler
should generate an error saying that the key isn't a constant (or isn't
comparable to some specific other key).
This patch has the effect of allowing the map literal to compile when
constant eval of the OEQ fails. If the keys are really equal (which the
map impl will notice at runtime), one will overwrite the other in the
resulting map. Not great, but better than a compiler crash.
Fixes #12536
Change-Id: Ic151a5e3f131c2e8efa0c25c9218b431c55c1b30
Reviewed-on: https://go-review.googlesource.com/14400 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Rob Pike [Tue, 8 Sep 2015 21:58:12 +0000 (14:58 -0700)]
text/template: provide a way to trim leading and trailing space between actions
Borrowing a suggestion from the issue listed below, we modify the lexer to
trim spaces at the beginning (end) of a block of text if the action immediately
before (after) is marked with a minus sign. To avoid parsing/lexing ambiguity,
we require an ASCII space between the minus sign and the rest of the action.
Thus:
{{23 -}}
<
{{- 45}}
produces the output
23<45
All the work is done in the lexer. The modification is invisible to the parser
or any outside package (except I guess for noticing some gaps in the input
if one tracks error positions). Thus it slips in without worry in text/template
and html/template both.
Fixes long-requested issue #9969.
Change-Id: I3774be650bfa6370cb993d0899aa669c211de7b2
Reviewed-on: https://go-review.googlesource.com/14391 Reviewed-by: Andrew Gerrand <adg@golang.org>
Michael Hudson-Doyle [Tue, 1 Sep 2015 02:07:14 +0000 (14:07 +1200)]
cmd/dist, cmd/link: force external linking for shared libs on arm
Also run testcshared.
Fixes #12425
Change-Id: I5baea8d772d3462f945aab96260b4197dbb20c0a
Reviewed-on: https://go-review.googlesource.com/14143 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Austin Clements [Sat, 29 Aug 2015 03:15:41 +0000 (23:15 -0400)]
runtime: move stack barrier code to its own file
Currently the stack barrier code is mixed in with the mark and scan
code. Move all of the stack barrier related functions and variables to
a new dedicated source file. There are no code modifications.
Change-Id: I604603045465ef8573b9f88915d28ab6b5910903
Reviewed-on: https://go-review.googlesource.com/14050 Reviewed-by: Rick Hudson <rlh@golang.org>
Michael Hudson-Doyle [Thu, 21 May 2015 01:07:19 +0000 (13:07 +1200)]
cmd/internal/ld: put read-only relocated data into .data.rel.ro when making a shared object
Currently Go produces shared libraries that cannot be shared between processes
because they have relocations against the text segment (not text section). This
fixes this by moving some data to sections with magic names recognized by the
static linker.
The change in genasmsym to add STYPELINK to the switch should fix things on
darwin/arm64.
Fixes #10914
Updates #9210
Change-Id: Iab4a6678dd04cec6114e683caac5cf31b1063309
Reviewed-on: https://go-review.googlesource.com/14306
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
Just a mechanical copy, no code changes.
This is to reduce code difference when adding the mips64 port.
Change-Id: Id06e975f414a7b09f4827167b30813b228a3bfaf
Reviewed-on: https://go-review.googlesource.com/14324 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Just a mechanical copy with filename renames, no code changes.
This is to reduce code difference when adding the mips64 port.
Change-Id: Id06e975f414a7b09f4827167b30813b228a3bfae
Reviewed-on: https://go-review.googlesource.com/14323 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Michael Hudson-Doyle [Mon, 7 Sep 2015 03:00:52 +0000 (15:00 +1200)]
cmd/internal/obj: remove dead code and small cleanups
Change-Id: I88fa0cc245a2141af04acced8716e08b1133abd1
Reviewed-on: https://go-review.googlesource.com/14350 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Some commits made by Aram from his personal email address are
actually copyright Oracle:
a77fcb3 net: fix comment in sendFile b0e71f4 net: link with networking libraries when net package is in use 92e959a syscall, net: use sendfile on Solaris db8d5b7 net: try to fix setKeepAlivePeriod on Solaris fe5ef5c runtime, syscall: link Solaris binaries directly instead of using dlopen/dlsym 2b90c3e go/build: enable cgo by default on solaris/amd64 2d18ab7 doc/progs: disable cgo tests that use C.Stdout on Solaris 2230e9d misc/cgo: add various solaris build lines 649c7b6 net: add cgo support for Solaris 24396da os/user: small fixes for Solaris 121489c runtime/cgo: add cgo support for solaris/amd64 83b25d9 cmd/ld: make .rela and .rela.plt sections contiguous c94f1f7 runtime: always load address of libcFunc on Solaris e481aac cmd/6l: use .plt instead of .got on Solaris
See bug for clarification.
Fixes #12452
Change-Id: I0aeb1b46c0c7d09c5c736e383ecf40240d2cf85f
Reviewed-on: https://go-review.googlesource.com/14380 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Rob Pike [Tue, 8 Sep 2015 17:58:21 +0000 (10:58 -0700)]
doc: mention that go install removes binaries built by go build
Fixes #12288.
For inclusion in the 1.5.1 release.
Change-Id: I9354b7eaa76000498465c4a5cbab7246de9ecb7c
Reviewed-on: https://go-review.googlesource.com/14382 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Dave Cheney [Sat, 5 Sep 2015 04:43:50 +0000 (14:43 +1000)]
cmd/compile: convert typecheck_stack to []*Node
This one of a set of changes to make the transition away from NodeList
easier by removing cases in which NodeList doesn't act semi-trivially like a
[]*Node.
This CL was originally prepared by Josh Bleecher Snyder <josharian@gmail.com>.
This change passes go build -toolexec 'toolstash -cmp' -a std.
cmd/asm: fix another infinite loop in register list parser
The code parsing register lists involves an inner loop on
each range defined by the lo,hi bounds. The condition on
this loop (for lo<=hi) is fragile, because the bounds
are unsigned 16 bits numbers.
In some corner cases, the calculated upper bound is 2^16-1
leading to an infinite loop.
Parsing operand `[):[o-FP` results in:
- an infinite loop for non ARM architectures
- the generation of almost 2^16 errors for the ARM architecture
(which are then ignored)
This CL improves the code in 3 ways:
- bail out early when parsing non R prefixed registers
- make sure the register index is never negative
- make sure the number of iterations is limited by the
maximum size of the range (as a defensive measure).
Fixes #12469
Change-Id: Ib1e7e36fb8ad5a3a52c50fc6219d3cfe2b39cc34
Reviewed-on: https://go-review.googlesource.com/14314 Reviewed-by: Rob Pike <r@golang.org>
Dave Cheney [Sat, 5 Sep 2015 02:30:13 +0000 (12:30 +1000)]
cmd/compile: use []*Node instead of NodeList in bottomUpVisitor
This one of a set of changes to make the transition away from NodeList
easier by removing cases in which NodeList doesn't act semi-trivially like a
[]*Node.
This CL was originally prepared by Josh Bleecher Snyder <josharian@gmail.com>.
This change passes go build -toolexec 'toolstash -cmp' -a std.
Change-Id: I582ff8b077eb384b84721a1edb0c1efbc0c40059
Reviewed-on: https://go-review.googlesource.com/14304 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-by: Dave Cheney <dave@cheney.net>
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Paul Marks [Sat, 5 Sep 2015 01:33:35 +0000 (18:33 -0700)]
net: Make Listen(":port") use IPv6 when IPv4 is not supported.
When running an experimental kernel with IPv4 disabled, Listen(":port")
currently tries to create an AF_INET socket, and fails. Instead, it
should see !supportsIPv4, and use an AF_INET6 socket.
This sort of environment is quite esoteric at the moment, but I can
force the tests to fail on regular Linux using the following tweaks:
- net/net.go: supportsIPv4, supportsIPv6, supportsIPv4map = false, true, false
- net/sockopt_linux.go: ipv6only=true
- net/ipsock_posix.go: Revert this fix
- ./make.bash && ../bin/go test net
Also, make the arrows in server_test.go point to the left, because
server<-client is easier to read.
Fixes #12510
Change-Id: I0cc3b6b08d5e6908d2fbf8594f652ba19815aa4b
Reviewed-on: https://go-review.googlesource.com/14334
Run-TryBot: Paul Marks <pmarks@google.com> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Dave Cheney [Thu, 3 Sep 2015 07:07:00 +0000 (17:07 +1000)]
cmd/compile: use []*Node instead of NodeList in sinit
This is a first of a set of changes to make the transition away from NodeList
easier by removing cases in which NodeList doesn't act semi-trivially like a
[]*Node.
This CL was originally prepared by Josh Bleecher Snyder <josharian@gmail.com>.
This change passes go build -toolexec 'toolstash -cmp' -a std.
Shawn Walker-Salas [Wed, 26 Aug 2015 22:24:41 +0000 (15:24 -0700)]
cmd/go: fix Go buildid reading on Solaris
TestNoteReading fails on Solaris with linkmode=external due to some
assumptions made about how ELF .note sections are written by some
linkers.
On current versions of Solaris and older derivatives, SHF_ALLOC is
intentionally ignored for .note sections unless the .note section is
assigned to the text segment via a mapfile. Also, if .note sections
are assigned to the text segment, no PT_NOTE program header will be
created thwarting Go's attempts at attempting to quickly find the
.note.
Furthermore, Go assumes that the relevant note segment will be placed
early in the file while the Solaris linker currently places the note
segment last in the file, additionally thwarting Go's optimisation
attempts that read only the first 16KB of the file to find the
buildid.
The fix is to detect when the note section is outside of the first
16KB of the file and then fallback to additionally reading that
section of the file. This way, in future versions of Solaris when
this linking behaviour is changed, the fast path will always succeed
and we'll only be slower if it fails; likewise, any other linker that
does this will also just work.
Change-Id: Ibd2dea475d6ce6a8b4b40e2da19a83fc0514025d
Reviewed-on: https://go-review.googlesource.com/14301 Reviewed-by: Ian Lance Taylor <iant@golang.org>