stkcheck is flow-insensitive: It processes calls in PC order.
Since morestack was always the first call in a function,
it was a safe, conservative approximation to simply adjust stack
space as we went, recognizing morestack when it showed up.
Subsequent CLS will rearrange the function prologue;
morestack may no longer be the first call in a function.
Introducing flow-sensitivity to stkcheck would allow this,
and possibly allow a smaller stackguard.
It is also a high risk change and possibly expensive.
Instead, assume that all calls to morestack occur as
part of the function prologue, no matter where they
are located in the program text.
Updates #10587.
Change-Id: I4dcdd4256a980fc4bc433a68a10989ff57f7034f
Reviewed-on: https://go-review.googlesource.com/10496
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Otherwise subsequent tests won't see any modified GOROOT.
With this CL I can move my GOROOT, set GOROOT to the new location, and
the runtime tests pass. Previously the crash_tests would instead look
for the GOROOT baked into the binary, instead of the env var:
--- FAIL: TestGcSys (0.01s)
crash_test.go:92: building source: exit status 2
go: cannot find GOROOT directory: /home/bradfitz/go
--- FAIL: TestGCFairness (0.01s)
crash_test.go:92: building source: exit status 2
go: cannot find GOROOT directory: /home/bradfitz/go
--- FAIL: TestGdbPython (0.07s)
runtime-gdb_test.go:64: building source exit status 2
go: cannot find GOROOT directory: /home/bradfitz/go
--- FAIL: TestLargeStringConcat (0.01s)
crash_test.go:92: building source: exit status 2
go: cannot find GOROOT directory: /home/bradfitz/go
Update #10029
Change-Id: If91be0f04d3acdcf39a9e773a4e7905a446bc477
Reviewed-on: https://go-review.googlesource.com/10685
Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
The only unreviewed change is in mparith3.go.
Change-Id: Iec0885e7688981cbaed04c152dc9b1c7032677e6
Reviewed-on: https://go-review.googlesource.com/10665
Reviewed-by: Alan Donovan <adonovan@google.com>
Run-TryBot: Robert Griesemer <gri@golang.org>
The build ID is an opaque token supplied by the build system.
The compiler writes it out early in the Go export metadata
(the second line), in a way that does not bother existing readers.
The intent is that the go command can use this to store information
about the sources for the generated code, so that it can detect
stale packages even in cases (like removed files) where mtimes fail.
Change-Id: Ib5082515d6cde8a07a8d4b5c69d1e8e4190cb5e1
Reviewed-on: https://go-review.googlesource.com/9153
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This one didn't get written out.
Change-Id: Iee173861fb4dc7cafa64ba5f601f4664b6e8da4e
Reviewed-on: https://go-review.googlesource.com/10681
Reviewed-by: Russ Cox <rsc@golang.org>
In particular, this avoids moving the mtime on runtime/zversion.go
forward unless the file is out of date. In turn, this makes cross compiles
that run dist multiple times coexist nicely.
(It's no longer necessary to run dist multiple times to set up cross compiles,
but people still might, and it's easy to fix regardless.)
Fixes#4749.
Change-Id: Id430525f168f106bc4b821ca74b2ca498a748f14
Reviewed-on: https://go-review.googlesource.com/9152
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
It was mishandling conjunctions containing negations.
Change-Id: Ife571b28416870ba2ceadbdac5ecb4670432bba1
Reviewed-on: https://go-review.googlesource.com/9151
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This is follow-up to CL10607
- Refactor AddParseTree() to use t.associate()
- Refactor Parse() to use AddParseTree() to put entries into common structure
- Clone() should not put entry in t.tmpl for undefined template
- Clarify documentation for Templates()
- Clarify documentation for AddParseTree() to include the error case
Updates #10910
Uodates #10926
Includes test cases for most of the above changes
Change-Id: I25b2fce6f9651272866f881acf44e4dbca04a4a8
Reviewed-on: https://go-review.googlesource.com/10622
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Also add a reference to the strings blog post.
Fixes#11045.
Change-Id: Ic0a8908cbd7b51a36d104849fa0e8abfd54de2b9
Reviewed-on: https://go-review.googlesource.com/10662
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Sending out the conversion of a single test to get comments on the
overall approach. Converting more tests will follow.
Change-Id: I4755442d08aeb6f74c46856ae406fec41cf8d5dc
Reviewed-on: https://go-review.googlesource.com/10464
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
It was an oversight (but as linux/arm64 doesn't support internal
linking and always use external linking with cgo, no harm is done.)
Change-Id: Ie5f2b445cb67a8e63d6b868e63379c68847554f9
Reviewed-on: https://go-review.googlesource.com/10636
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Currently the GODEBUG=gctrace=1 trace line includes "@n.nnns" to
indicate the time that the GC cycle ended relative to the time the
program started. This was meant to be consistent with the utilization
as of the end of the cycle, which is printed next on the trace line,
but it winds up just being confusing and unexpected.
Change the trace line to include the time that the GC cycle started
relative to the time the program started.
Change-Id: I7d64580cd696eb17540716d3e8a74a9d6ae50650
Reviewed-on: https://go-review.googlesource.com/10634
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Due to the requirements of parsing template definitions that mention
other templates that are not yet defined, a Template can be in two states:
defined and undefined. Thus, although one calls New, the resulting
template has no definition even though it exists as a data structure.
Thus, for example, will return nil for a template that is named but not
yet defined.
Fixes#10910Fixes#10926
Clarify the documentation a little to explain this,
Also tidy up the code a little and remove a spurious call to init.
Change-Id: I22cc083291500bca424e83dc12807e0de7b00b7a
Reviewed-on: https://go-review.googlesource.com/10641
Reviewed-by: Andrew Gerrand <adg@golang.org>
This commit implements stack barriers to minimize the amount of
stack re-scanning that must be done during mark termination.
Currently the GC scans stacks of active goroutines twice during every
GC cycle: once at the beginning during root discovery and once at the
end during mark termination. The second scan happens while the world
is stopped and guarantees that we've seen all of the roots (since
there are no write barriers on writes to local stack
variables). However, this means pause time is proportional to stack
size. In particularly recursive programs, this can drive pause time up
past our 10ms goal (e.g., it takes about 150ms to scan a 50MB heap).
Re-scanning the entire stack is rarely necessary, especially for large
stacks, because usually most of the frames on the stack were not
active between the first and second scans and hence any changes to
these frames (via non-escaping pointers passed down the stack) were
tracked by write barriers.
To efficiently track how far a stack has been unwound since the first
scan (and, hence, how much needs to be re-scanned), this commit
introduces stack barriers. During the first scan, at exponentially
spaced points in each stack, the scan overwrites return PCs with the
PC of the stack barrier function. When "returned" to, the stack
barrier function records how far the stack has unwound and jumps to
the original return PC for that point in the stack. Then the second
scan only needs to proceed as far as the lowest barrier that hasn't
been hit.
For deeply recursive programs, this substantially reduces mark
termination time (and hence pause time). For the goscheme example
linked in issue #10898, prior to this change, mark termination times
were typically between 100 and 500ms; with this change, mark
termination times are typically between 10 and 20ms. As a result of
the reduced stack scanning work, this reduces overall execution time
of the goscheme example by 20%.
Fixes#10898.
The effect of this on programs that are not deeply recursive is
minimal:
name old time/op new time/op delta
BinaryTree17 3.16s ± 2% 3.26s ± 1% +3.31% (p=0.000 n=19+19)
Fannkuch11 2.42s ± 1% 2.48s ± 1% +2.24% (p=0.000 n=17+19)
FmtFprintfEmpty 50.0ns ± 3% 49.8ns ± 1% ~ (p=0.534 n=20+19)
FmtFprintfString 173ns ± 0% 175ns ± 0% +1.49% (p=0.000 n=16+19)
FmtFprintfInt 170ns ± 1% 175ns ± 1% +2.97% (p=0.000 n=20+19)
FmtFprintfIntInt 288ns ± 0% 295ns ± 0% +2.73% (p=0.000 n=16+19)
FmtFprintfPrefixedInt 242ns ± 1% 252ns ± 1% +4.13% (p=0.000 n=18+18)
FmtFprintfFloat 324ns ± 0% 323ns ± 0% -0.36% (p=0.000 n=20+19)
FmtManyArgs 1.14µs ± 0% 1.12µs ± 1% -1.01% (p=0.000 n=18+19)
GobDecode 8.88ms ± 1% 8.87ms ± 0% ~ (p=0.480 n=19+18)
GobEncode 6.80ms ± 1% 6.85ms ± 0% +0.82% (p=0.000 n=20+18)
Gzip 363ms ± 1% 363ms ± 1% ~ (p=0.077 n=18+20)
Gunzip 90.6ms ± 0% 90.0ms ± 1% -0.71% (p=0.000 n=17+18)
HTTPClientServer 51.5µs ± 1% 50.8µs ± 1% -1.32% (p=0.000 n=18+18)
JSONEncode 17.0ms ± 0% 17.1ms ± 0% +0.40% (p=0.000 n=18+17)
JSONDecode 61.8ms ± 0% 63.8ms ± 1% +3.11% (p=0.000 n=18+17)
Mandelbrot200 3.84ms ± 0% 3.84ms ± 1% ~ (p=0.583 n=19+19)
GoParse 3.71ms ± 1% 3.72ms ± 1% ~ (p=0.159 n=18+19)
RegexpMatchEasy0_32 100ns ± 0% 100ns ± 1% -0.19% (p=0.033 n=17+19)
RegexpMatchEasy0_1K 342ns ± 1% 331ns ± 0% -3.41% (p=0.000 n=19+19)
RegexpMatchEasy1_32 82.5ns ± 0% 81.7ns ± 0% -0.98% (p=0.000 n=18+18)
RegexpMatchEasy1_1K 505ns ± 0% 494ns ± 1% -2.16% (p=0.000 n=18+18)
RegexpMatchMedium_32 137ns ± 1% 137ns ± 1% -0.24% (p=0.048 n=20+18)
RegexpMatchMedium_1K 41.6µs ± 0% 41.3µs ± 1% -0.57% (p=0.004 n=18+20)
RegexpMatchHard_32 2.11µs ± 0% 2.11µs ± 1% +0.20% (p=0.037 n=17+19)
RegexpMatchHard_1K 63.9µs ± 2% 63.3µs ± 0% -0.99% (p=0.000 n=20+17)
Revcomp 560ms ± 1% 522ms ± 0% -6.87% (p=0.000 n=18+16)
Template 75.0ms ± 0% 75.1ms ± 1% +0.18% (p=0.013 n=18+19)
TimeParse 358ns ± 1% 364ns ± 0% +1.74% (p=0.000 n=20+15)
TimeFormat 360ns ± 0% 372ns ± 0% +3.55% (p=0.000 n=20+18)
Change-Id: If8a9bfae6c128d15a4f405e02bcfa50129df82a2
Reviewed-on: https://go-review.googlesource.com/10314
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently there's a race between stopg scanning another G's stack and
the G reaching a preemption point and scanning its own stack. When
this race occurs, the G's stack is scanned twice. Currently this is
okay, so this race is benign.
However, we will shortly be adding stack barriers during the first
stack scan, so scanning will no longer be idempotent. To prepare for
this, this change ensures that each stack is scanned only once during
each GC phase by checking the flag that indicates that the stack has
been scanned in this phase before scanning the stack.
Change-Id: Id9f4d5e2e5b839bc3f200ec1723a4a12dd677ab4
Reviewed-on: https://go-review.googlesource.com/10458
Reviewed-by: Rick Hudson <rlh@golang.org>
The stack barrier code will need a bookkeeping structure to keep track
of the overwritten return PCs. This commit introduces and allocates
this structure, but does not yet use the structure.
We don't want to allocate space for this structure during garbage
collection, so this commit allocates it along with the allocation of
the corresponding stack. However, we can't do a regular allocation in
newstack because mallocgc may itself grow the stack (which would lead
to a recursive allocation). Hence, this commit makes the bookkeeping
structure part of the stack allocation itself by stealing the
necessary space from the top of the stack allocation. Since the size
of this bookkeeping structure is logarithmic in the size of the stack,
this has minimal impact on stack behavior.
Change-Id: Ia14408be06aafa9ca4867f4e70bddb3fe0e96665
Reviewed-on: https://go-review.googlesource.com/10313
Reviewed-by: Russ Cox <rsc@golang.org>
Currently the runtime assumes that the allocation for the stack is
exactly [stack.lo, stack.hi). We're about to steal a small part of
this allocation for per-stack GC metadata. To prepare for this, this
commit adds a field to the G for the allocated size of the stack.
With this change, stack.lo and stack.hi continue to act as the true
bounds on the stack, but are no longer also used as the bounds on the
stack allocation.
(I also tried this the other way around, where stack.lo and stack.hi
remained the allocation bounds and I introduced a new top of stack.
However, there are far more places that assume stack.hi is the true
top of the stack than there are places that assume it's the top of the
allocation.)
Change-Id: Ifa9d956753be53d286d09cbc73d47fb34a18c0c6
Reviewed-on: https://go-review.googlesource.com/10312
Reviewed-by: Russ Cox <rsc@golang.org>
Currently signalstack takes a lower limit and a length and all calls
hard-code the passed length. Change the API to take a *stack and
compute the lower limit and length from the passed stack.
This will make it easier for the runtime to steal some space from the
top of the stack since it eliminates the hard-coded stack sizes.
Change-Id: I7d2a9f45894b221f4e521628c2165530bbc57d53
Reviewed-on: https://go-review.googlesource.com/10311
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Currently we truncate gctrace clock and CPU times to millisecond
precision. As a result, many phases are typically printed as 0, which
is fine for user consumption, but makes gathering statistics and
reports over GC traces difficult.
In 1.4, the gctrace line printed times in microseconds. This was
better for statistics, but not as easy for users to read or interpret,
and it generally made the trace lines longer.
This change strikes a balance between these extremes by printing
milliseconds, but including the decimal part to two significant
figures down to microsecond precision. This remains easy to read and
interpret, but includes more precision when it's useful.
For example, where the code currently prints,
gc #29 @1.629s 0%: 0+2+0+12+0 ms clock, 0+2+0+0/12/0+0 ms cpu, 4->4->2 MB, 4 MB goal, 1 P
this prints,
gc #29 @1.629s 0%: 0.005+2.1+0+12+0.29 ms clock, 0.005+2.1+0+0/12/0+0.29 ms cpu, 4->4->2 MB, 4 MB goal, 1 P
Fixes#10970.
Change-Id: I249624779433927cd8b0947b986df9060c289075
Reviewed-on: https://go-review.googlesource.com/10554
Reviewed-by: Russ Cox <rsc@golang.org>
The Error function is a potential XSS vector if a user can control the
error message.
For example, an http.FileServer when given a request for this path
/<script>alert("xss!")</script>
may return a response with a body like this
open <script>alert("xss!")</script>: no such file or directory
Browsers that sniff the content may interpret this as HTML and execute
the script. The nosniff header added by this CL should help, but we
should also try santizing the output entirely.
Change-Id: I447f701531329a2fc8ffee2df2f8fa69d546f893
Reviewed-on: https://go-review.googlesource.com/10640
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Allow room for the initial minus sign of negative integers when
computing widths.
Fixes#10945.
Change-Id: I04d80203aaff64611992725d613ec13ed2ae721f
Reviewed-on: https://go-review.googlesource.com/10393
Reviewed-by: Rob Pike <r@golang.org>
This change fixes incorrect parsing of literal IP addresses in local
database when the addresses contain IPv6 zone identifiers, are in
dotted-decimal notation or in colon-hexadecimal notation with leading
zeros.
https://golang.org/cl/5851 already fixed the code path using getaddrinfo
via cgo. This change fixes the remaining non-cgo code path.
Fixes#8243.
Fixes#8996.
Change-Id: I48443611cbabed0d69667cc73911ba3de396fd44
Reviewed-on: https://go-review.googlesource.com/10306
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Fixes an error where the compiler did not spot that the shadowed err
value was set again after being read. That second assignment was lost
as the value was redeclared in an inner scope.
Spotted by Gordon Klass, https://groups.google.com/forum/#!topic/golang-nuts/MdDLbvOjb4o
Change-Id: I28f2da6f98c52afcbb45e17d2b4f36c586598f98
Reviewed-on: https://go-review.googlesource.com/10600
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
