The funcdata symbol incorrectly named the dead value map the
dead pointer map. The dead value map identifies all dead
values, including pointers and non-pointers, in a stack frame.
The purpose of this map is to allow the runtime to poison
locations of dead data to catch lost invariants.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/38670043
The new linker will disallow this on arm
(it is already disallowed on amd64 and 386)
in order to be able to lay out each function
separately.
The restriction is only for jumps into the middle
of a function; jumps to the beginning of a function
remain fine.
Prereq for linker cleanup (golang.org/s/go13linker).
R=iant, r, minux.ma
CC=golang-dev
https://golang.org/cl/35800043
When enabled this new debugging mode will allocate objects on
their own page and never recycle memory addresses. This is an
essential tool to root cause a broad class of heap corruption.
R=golang-dev, dave, daniel.morsing, dvyukov, rsc, iant, cshapiro
CC=golang-dev
https://golang.org/cl/22060046
This change allows the garbage collector to examine stack
slots that are determined as live and containing a pointer
value by the garbage collector. This results in a mean
reduction of 65% in the number of stack slots scanned during
an invocation of "GOGC=1 all.bash".
Unfortunately, this does not yet allow garbage collection to
be precise for the stack slots computed as live. Pointers
confound the determination of what definitions reach a given
instruction. In general, this problem is not solvable without
runtime cost but some advanced cooperation from the compiler
might mitigate common cases.
R=golang-dev, rsc, cshapiro
CC=golang-dev
https://golang.org/cl/14430048
Pass as a slice of strings instead. For 2-5 strings, implement
dedicated routines so no slices are needed.
static call counts in the go binary:
2 strings: 342 occurrences
3 strings: 98
4 strings: 30
5 strings: 13
6+ strings: 14
Why? C varags, bad for stack scanning and copying.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/36380043
Now that the map implementation is reading the keys and values from
arbitrary memory (instead of from stack slots), it needs to tell the
race detector when it does so.
Fixes#6875.
R=golang-dev, dave
CC=golang-dev
https://golang.org/cl/36360043
and methodValueCall directly. Instead, we inline their behavior
inside of reflect.call.
This change is required because otherwise we have a situation where
reflect.callXX calls makeFuncStub, neither of which knows the
layout of the args passed between them. That's bad for
precise gc & stack copying.
Fixes#6619.
R=golang-dev, dvyukov, rsc, iant, khr
CC=golang-dev
https://golang.org/cl/26970044
This change is part of the plan to get rid of all vararg C calls
which are a pain for getting exact stack scanning.
We allocate a chunk of zero memory to return a pointer to when a
map access doesn't find the key. This is simpler than returning nil
and fixing things up in the caller. Linker magic allocates a single
zero memory area that is shared by all (non-reflect-generated) map
types.
Passing things by reference gets rid of some copies, so it speeds
up code with big keys/values.
benchmark old ns/op new ns/op delta
BenchmarkBigKeyMap 34 31 -8.48%
BenchmarkBigValMap 37 30 -18.62%
BenchmarkSmallKeyMap 26 23 -11.28%
R=golang-dev, dvyukov, khr, rsc
CC=golang-dev
https://golang.org/cl/14794043
Two bugs:
1. The first iteration of the traceback always uses LR when provided,
which it is (only) during a profiling signal, but in fact LR is correct
only if the stack frame has not been allocated yet. Otherwise an
intervening call may have changed LR, and the saved copy in the stack
frame should be used. Fix in traceback_arm.c.
2. The division runtime call adds 8 bytes to the stack. In order to
keep the traceback routines happy, it must copy the saved LR into
the new 0(SP). Change
SUB $8, SP
into
MOVW 0(SP), R11 // r11 is temporary, for use by linker
MOVW.W R11, -8(SP)
to update SP and 0(SP) atomically, so that the traceback always
sees a saved LR at 0(SP).
Fixes#6681.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/19910044
The CL causes misc/cgo/test to fail randomly.
I suspect that the problem is the use of a division instruction
in usleep, which can be called while trying to acquire an m
and therefore cannot store the denominator in m.
The solution to that would be to rewrite the code to use a
magic multiply instead of a divide, but now we're getting
pretty far off the original code.
Go back to the original in preparation for a different,
less efficient but simpler fix.
««« original CL description
cmd/5l, runtime: make ARM integer division profiler-friendly
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes#6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
»»»
TBR=r
CC=golang-dev
https://golang.org/cl/20350043
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes#6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
Most Unix systems have their own time zone data,
so we almost never get far enough in the list to
discover that we cannot fall back to the zip file.
Adjust testing to exercise the final fallback.
Plan 9 and Windows were already correct
(and are the main users of the zip file).
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/19280043
This CL restores the Go 1.1.2 semantics for os.File's Readdir method.
The code in Go 1.1.2 was rewritten mainly because it looked buggy.
This new version attempts to be clearer but still provide the 1.1.2 results.
The important diff is not this CL's version against tip but this CL's version
against Go 1.1.2.
Go 1.1.2:
names, err := f.Readdirnames(n)
fi = make([]FileInfo, len(names))
for i, filename := range names {
fip, err := Lstat(dirname + filename)
if err == nil {
fi[i] = fip
} else {
fi[i] = &fileStat{name: filename}
}
}
return fi, err
This CL:
names, err := f.Readdirnames(n)
fi = make([]FileInfo, len(names))
for i, filename := range names {
fip, lerr := lstat(dirname + filename)
if lerr != nil {
fi[i] = &fileStat{name: filename}
continue
}
fi[i] = fip
}
return fi, err
The changes from Go 1.1.2 are stylistic, not semantic:
1. Use lstat instead of Lstat, for testing (done before this CL).
2. Make error handling in loop body look more like an error case.
3. Use separate error variable name in loop body, to be clear
we are not trying to influence the final return result.
Fixes#6656.
Fixes#6680.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/18870043
Some versions of clang generate DWARF 4-format attributes
even when using -gdwarf-2. We don't care much about the
values, but we do need to be able to parse past them.
This fixes a bug in Go 1.2 rc2 reported via private mail using
a near-tip version of clang.
R=golang-dev, iant, dvyukov
CC=golang-dev
https://golang.org/cl/18460043
The case can happen when starttheworld is calling acquirep
to get things moving again and acquirep gets preempted.
The stack trace is in golang.org/issue/6644.
It is difficult to build a short test case for this, but
the person who reported issue 6644 confirms that this
solves the problem.
Fixes#6644.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/18740044
Encoded query strings are always sorted by key; the example wasn't.
R=golang-dev, dsymonds, minux.ma, bradfitz
CC=golang-dev
https://golang.org/cl/16430043
singleStringReplacer had a bug where if a string was replaced
at the beginning and no output had yet been produced into the
temp buffer before matching ended, an invalid nil check (used
as a proxy for having matched anything) meant it always
returned its input.
Fixes#6659
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/16880043
The routines in this file are dregs from a very early copy of the math API.
There are no Go prototypes and no non-amd64 implementations.
R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/15750046
The code was requiring that all constraints be met, but it should be
satisfied by meeting *any* of them.
R=golang-dev, bradfitz, r
CC=golang-dev
https://golang.org/cl/15570044
Despite SHA256 support being required for TLS 1.2 handshakes, some
servers are aborting handshakes that don't offer SHA1 support.
This change adds support for signing TLS 1.2 ServerKeyExchange messages
with SHA1. It does not add support for signing TLS 1.2 client
certificates with SHA1 as that would require the handshake to be
buffered.
Fixes#6618.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/15650043
Nomemprof seems to be unneeded now, there is no recursion.
If the recursion will be re-introduced, it will break loudly by deadlocking.
Fixes#6566.
R=golang-dev, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/14695044
Only add a slash to path if it's a separator between
a host and path.
Fixes#6609
R=golang-dev, dsymonds, r
CC=golang-dev
https://golang.org/cl/14815043
New test added in CL 14611045 causes a deadlock when
running the tests with -cpu=n,n because the fakedb
driver always waits when opening a new connection after
running TestConnectionLeak. Reset its state after.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/14780043
CL 10726044 introduced a race condition which causes connections
to be leaked under certain circumstances. If SetMaxOpenConns is
used, the application eventually deadlocks. Otherwise, the number
of open connections just keep growing indefinitely.
Fixes#6593
R=golang-dev, bradfitz, tad.glines, bketelsen
CC=golang-dev
https://golang.org/cl/14611045
Add a check at the end of every test to make sure
there are no leaked connections after running a test.
Avoid incorrectly decrementing the number of open connections
when the driver connection ends up it a bad state (numOpen was
decremented twice).
Prevent leaking a Rows struct (which ends up leaking a
connection) in Row.Scan() when a *RawBytes destination is
improperly used.
Close the Rows struct in TestRowsColumns.
Update #6593
R=golang-dev, bradfitz, dave
CC=golang-dev
https://golang.org/cl/14642044
Fixes a bug in cgo on OS X using clang.
See golang.org/issue/6472 for details.
Fixes#6472.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/14575043
Also tweak the package document, putting in section headings and
adding a sentence about intended use.
Fixes#4925.
R=golang-dev, iant, adg, ugorji
CC=golang-dev
https://golang.org/cl/14519044
Instead of adding an -march=armv5t flag to the gcc command
line, the same effect is obtained with an ".arch armv5t"
pseudo op in the assembly file that uses armv5t instructions.
R=golang-dev, iant, dave
CC=golang-dev
https://golang.org/cl/14511044
All of the currently supported platforms have a working user
implementation and do not use stubs. As a result, enable the tests
on all platforms rather than whitelisting.
R=golang-dev, dave, iant
CC=golang-dev
https://golang.org/cl/14454044
If an iterator is started while a map is in the middle of a grow,
and the map has NaN keys, then those keys might get returned by
the iterator more than once. This fix makes the evacuation decision
deterministic and repeatable for NaN keys so each one gets returned
only once.
R=golang-dev, r, khr, iant
CC=golang-dev
https://golang.org/cl/14367043
Failure occurred when using reflect.Call to pass a func value
following a non-pointer value.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/14186043
Explain for those unfamiliar with twos-complement arithmetic how to
implement negation of signed positive constant.
Fixes#6408.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/14267044
Changing from 4 kB to 8 kB brings significant improvement
on a variety of the Go 1 benchmarks, on both amd64
and 386 systems.
Significant runtime reductions:
amd64 386
GoParse -14% -1%
GobDecode -12% -20%
GobEncode -64% -1%
JSONDecode -9% -4%
JSONEncode -15% -5%
Template -17% -14%
In the longer term, khr's new stacks will avoid needing to
make this decision at all, but for Go 1.2 this is a reasonable
stopgap that makes performance significantly better.
Demand paging should mean that if the second 4 kB is not
used, it will not be brought into memory, so the change
should not adversely affect resident set size.
The same argument could justify bumping as high as 64 kB
on 64-bit machines, but there are diminishing returns
after 8 kB, and using 8 kB limits the possible unintended
memory overheads we are not aware of.
Benchmark graphs at
http://swtch.com/~rsc/gostackamd64.htmlhttp://swtch.com/~rsc/gostack386.html
Full data at
http://swtch.com/~rsc/gostack.zip
R=golang-dev, khr, dave, bradfitz, dvyukov
CC=golang-dev
https://golang.org/cl/14317043
It is not possible to use (there is no declaration in package syscall),
and no one seems to care.
Alex Brainman may bring this back properly for Go 1.3.
Fixes#6338.
R=golang-dev, r, alex.brainman
CC=golang-dev
https://golang.org/cl/14287043
RawMessage is useful and mildly non-obvious.
Given the frequency with which RawMessage questions
show up on golang-nuts, and get answered with an example,
I suspect adding an example to the docs might help.
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/14190044
Not scanning the stack by frames means we are reintroducing
a few false positives into the collection. Run the finalizer registration
in its own goroutine so that stack is guaranteed to be out of
consideration in a later collection.
This is working around a regression from yesterday's tip, but
it's not a regression from Go 1.1.
R=golang-dev
TBR=golang-dev
CC=golang-dev
https://golang.org/cl/14290043
Ticket 13740047 updated the documented TLS version to 1.2.
This also updates the RFC refered to.
R=golang-dev
CC=golang-dev, rsc
https://golang.org/cl/14029043
The argument slice was kept hidden from the garbage collector
by destroying its referent in an unsafe.Pointer to uintptr
conversion. This change preserves the unsafe.Pointer referent
and only performs an unsafe.Pointer to uintptr conversions
within expressions that construct new unsafe.Pointer values.
R=golang-dev, khr, rsc
CC=golang-dev
https://golang.org/cl/14008043
AES-GCM cipher suites are only defined for TLS 1.2, although there's
nothing really version specific about them. However, development
versions of NSS (meaning Firefox and Chrome) have an issue where
they'll advertise TLS 1.2-only cipher suites in a TLS 1.1 ClientHello
but then balk when the server selects one.
This change causes Go clients not to advertise TLS 1.2 cipher suites
unless TLS 1.2 is being used, and prevents servers from selecting them
unless TLS 1.2 has been negotiated.
https://code.google.com/p/chromium/issues/detail?id=297151https://bugzilla.mozilla.org/show_bug.cgi?id=919677
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/13573047
After text/template.Parse, all the templates may have changed, so
we need to set them all back to their unescaped state. The code
did this but (mea culpa) forgot to set the Tree field of the html/template
struct.
Since the Tree is reset during escaping, this only matters if an error
arises during escaping and we want to print a message.
Fixes#6459.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/13877043
If Slice3 is set, the expression is
a 3-index slice expression (2 colons).
Required for type-checking.
Backward-compatible API extension.
R=r, rsc
CC=golang-dev
https://golang.org/cl/13826050
Since CL 38bf89161a72 raw socket tests are not executed
on windows builders. This change re-enable them again.
It will attempt to run raw socket tests only if user
is permitted to create raw socket by OS.
Fixes#6392
R=golang-dev
CC=golang-dev, mikioh.mikioh, rsc
https://golang.org/cl/13422044
newTypeEncoder (called once per type and then cached) was
looking at the first value seen of that type's addressability
and caching the encoder decision. If the first value seen was
addressable and a future one wasn't, it would panic.
Instead, introduce a new wrapper encoder type that checks
CanAddr at runtime.
Fixes#6458
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/13839045
Makes build unnecessarily slower. Will fix the parser instead.
««« original CL description
runtime/pprof: run TestGoroutineSwitch for longer
Short test now takes about 0.5 second here.
Fixes#6417.
The failure was also seen on our builders.
R=golang-dev, minux.ma, r
CC=golang-dev
https://golang.org/cl/13321048
»»»
R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/13720048
In an indexed verb such as %[3]d, if the index is out of range, don't
skip processing the rest of the verbs. The bug was that the bad
index set a bit for the whole format instead of just the verb.
Ok for 1.2 because this is a bug in a 1.2 feature.
Fixes#6434
R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/13632058
Date header indicated that it contained GMT time,
however it actually sent local time. Fixed by
converting time to UTC.
Also fixes incorrect comment in appendTime().
Regression since CL 9432046.
R=golang-dev, dave, bradfitz
CC=golang-dev
https://golang.org/cl/13386047
Short test now takes about 0.5 second here.
Fixes#6417.
The failure was also seen on our builders.
R=golang-dev, minux.ma, r
CC=golang-dev
https://golang.org/cl/13321048
If a fault happens in malloc, inevitably the next thing that happens
is a deadlock trying to allocate the panic value that says the fault
happened. Stop doing that, two ways.
First, reject panic in malloc just as we reject panic in garbage collection.
Second, runtime.panicstring was using an error implementation
backed by a Go string, so the interface held an allocated *string.
Since the actual errors are C strings, define a new error
implementation backed by a C char*, which needs no indirection
and therefore no allocation.
This second fix will avoid allocation for errors like nil panic derefs
or division by zero, so it is worth doing even though the first fix
should take care of faults during malloc.
Update #6419
R=golang-dev, dvyukov, dave
CC=golang-dev
https://golang.org/cl/13774043
Keeping pointers from the pre-walk phase confuses
the race detection instrumentation.
Fixes#6418.
R=golang-dev, dvyukov, r
CC=golang-dev
https://golang.org/cl/13368057
47ec7a68b1a2 added support for ECDSA ciphersuites but didn't alter the
cipher suite selection to take that into account. Thus Go servers could
try and select an ECDSA cipher suite while only having an RSA
certificate, leading to connection failures.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/13239053
This interface is required to use the PCDATA interface
implemented in Go 1.2. While initially entirely private, the
FUNCDATA side of the interface has been made public. This
change completes the FUNCDATA/PCDATA interface.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/13735043
The code for call site-specific pointer bitmaps was not ready in time,
but the zeroing required without it is too expensive to use by default.
We will have to wait for precise collection of stack frames until Go 1.3.
The precise collection can be re-enabled by
GOEXPERIMENT=precisestack ./all.bash
but that will not be the default for a Go 1.2 build.
Fixes#6087.
R=golang-dev, jeremyjackins, dan.kortschak, r
CC=golang-dev
https://golang.org/cl/13677045
With TLS 1.2, when sending client certificates the code was omitting
the new (in TLS 1.2) signature and hash fields.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/13413050
The uint64 divide function calls _mul64x32 to do a 64x32-bit multiply
and then compares the result against the 64-bit numerator.
If the result is bigger than the numerator, must use the slow path.
Unfortunately, the 64x32 produces a 96-bit product, and only the
low 64 bits were being used in the comparison. Return all 96 bits,
the bottom 64 via the original uint64* pointer, and the top 32
as the function's return value.
Fixes 386 build (broken by ARM division tests).
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/13722044
This CL is required for all.bat to work out of the box on
my Windows 8 laptop.
These tests either require the firewall to be turned off
or require the user to be in the Administrators group.
I don't know which.
Alex may follow up with a refinement of the test to
allow them to run if the user is in the Administrators
group.
Fixes#6392.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/13421049
Because we can, and because it otherwise might crash
the program if we think we're out of memory.
Fixes#6390.
R=golang-dev, iant, minux.ma
CC=golang-dev
https://golang.org/cl/13345048
The implementation of division in the 5 toolchain is a bit too magical.
Hide the magic from the traceback routines.
Also add a test for the results of the software divide routine.
Fixes#5805.
R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/13239052
The kernel implementation of the fast system call path,
the one invoked by the SYSCALL instruction, is broken for
restarting system calls. A C program demonstrating this is below.
Change the system calls to use INT $0x80 instead, because
that (perhaps slightly slower) system call path actually works.
I filed http://www.freebsd.org/cgi/query-pr.cgi?pr=182161.
The C program demonstrating that it is FreeBSD's fault is below.
It reports the same "Bad address" failures from wait.
#include <sys/time.h>
#include <sys/signal.h>
#include <pthread.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
static void handler(int);
static void* looper(void*);
int
main(void)
{
int i;
struct sigaction sa;
pthread_cond_t cond;
pthread_mutex_t mu;
memset(&sa, 0, sizeof sa);
sa.sa_handler = handler;
sa.sa_flags = SA_RESTART;
memset(&sa.sa_mask, 0xff, sizeof sa.sa_mask);
sigaction(SIGCHLD, &sa, 0);
for(i=0; i<2; i++)
pthread_create(0, 0, looper, 0);
pthread_mutex_init(&mu, 0);
pthread_mutex_lock(&mu);
pthread_cond_init(&cond, 0);
for(;;)
pthread_cond_wait(&cond, &mu);
return 0;
}
static void
handler(int sig)
{
}
int
mywait4(int pid, int *stat, int options, struct rusage *rusage)
{
int result;
asm("movq %%rcx, %%r10; syscall"
: "=a" (result)
: "a" (7),
"D" (pid),
"S" (stat),
"d" (options),
"c" (rusage));
}
static void*
looper(void *v)
{
int pid, stat, out;
struct rusage rusage;
for(;;) {
if((pid = fork()) == 0)
_exit(0);
out = mywait4(pid, &stat, 0, &rusage);
if(out != pid) {
printf("wait4 returned %d\n", out);
}
}
}
Fixes#6372.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/13582047
Previously, fields of type chan or func caused an error.
Now we just treat them like unexported fields and ignore them.
This makes it easier to guarantee long-term compatibilty since
a substructure from another package cannot break gob
encoding by adding a func or chan field.
Fixes#6071
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/13693043
The test 'gp == m->curg' is not valid on Windows,
because the goroutine being profiled is not from the
current m.
TBR=golang-dev
CC=golang-dev
https://golang.org/cl/13718043
Because profiling signals can arrive at any time, we must
handle the case where a profiling signal arrives halfway
through a goroutine switch. Luckily, although there is much
to think through, very little needs to change.
Fixes#6000.
Fixes#6015.
R=golang-dev, dvyukov
CC=golang-dev
https://golang.org/cl/13421048
Fixes#6355.
zerrors_linux_{386,amd64,arm}.go were regenerated using mkerrors.sh but I opted to add the three TC.*FLUSH lines by hand to keep the diff smaller and avoid problems with the API checker.
I'll check freebsd and darwin, could I ask for help with net/open bsd.
R=mikioh.mikioh, jsing, minux.ma, bradfitz
CC=golang-dev
https://golang.org/cl/13660043
It's too late to change this behavior: it breaks templates with minimized JavaScript.
Makes me sad because this common error can never be caught: "{foo}}".
Three cheers for compatibility.
(Leave in a fix to a broken test.)
R=golang-dev, dsymonds, rsc
CC=golang-dev
https://golang.org/cl/13689043
Bug #1:
Issue 5406 identified an interesting case:
defer iface.M()
may end up calling a wrapper that copies an indirect receiver
from the iface value and then calls the real M method. That's
two calls down, not just one, and so recover() == nil always
in the real M method, even during a panic.
[For the purposes of this entire discussion, a wrapper's
implementation is a function containing an ordinary call, not
the optimized tail call form that is somtimes possible. The
tail call does not create a second frame, so it is already
handled correctly.]
Fix this bug by introducing g->panicwrap, which counts the
number of bytes on current stack segment that are due to
wrapper calls that should not count against the recover
check. All wrapper functions must now adjust g->panicwrap up
on entry and back down on exit. This adds slightly to their
expense; on the x86 it is a single instruction at entry and
exit; on the ARM it is three. However, the alternative is to
make a call to recover depend on being able to walk the stack,
which I very much want to avoid. We have enough problems
walking the stack for garbage collection and profiling.
Also, if performance is critical in a specific case, it is already
faster to use a pointer receiver and avoid this kind of wrapper
entirely.
Bug #2:
The old code, which did not consider the possibility of two
calls, already contained a check to see if the call had split
its stack and so the panic-created segment was one behind the
current segment. In the wrapper case, both of the two calls
might split their stacks, so the panic-created segment can be
two behind the current segment.
Fix this by propagating the Stktop.panic flag forward during
stack splits instead of looking backward during recover.
Fixes#5406.
R=golang-dev, iant
CC=golang-dev
https://golang.org/cl/13367052
The public key serialization from CreateCertificate is factored out to be
used in MarshalPKIXPublicKey.
Testcode with one P224 ECDSA keypair has been added.
R=golang-dev, agl
CC=agl, golang-dev
https://golang.org/cl/13427044
It was simply a missing error case: when scanning plain text
outside of an action, a right delimiter should be an error.
R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/13468045
Reduces a number of trials but it still can detect memory leak
when we make blunders in runtime-integarted network poller work,
like just forgetting to call runtime_pollClose in code paths.
Also disables the test on windows/386.
R=alex.brainman, r
CC=golang-dev
https://golang.org/cl/13022046
