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2530 Commits

Author SHA1 Message Date
Austin Clements
d5bd797ee5 runtime: fix getArgInfo for deferred reflection calls
getArgInfo for reflect.makeFuncStub and reflect.methodValueCall is
necessarily special. These have dynamically determined argument maps
that are stored in their context (that is, their *funcval). These
functions are written to store this context at 0(SP) when called, and
getArgInfo retrieves it from there.

This technique works if getArgInfo is passed an active call frame for
one of these functions. However, getArgInfo is also used in
tracebackdefers, where the "call" is not a true call with an active
stack frame, but a deferred call. In this situation, getArgInfo
currently crashes because tracebackdefers passes a frame with sp set
to 0. However, the entire approach used by getArgInfo is flawed in
this situation because the wrapper has not actually executed, and
hence hasn't saved this metadata to any stack frame.

In the defer case, we know the *funcval from the _defer itself, so we
can fix this by teaching getArgInfo to use the *funcval context
directly when its available, and otherwise get it from the active call
frame.

While we're here, this commit simplifies getArgInfo a bit by making it
play more nicely with the type system. Rather than decoding the
*reflect.methodValue that is the wrapper's context as a *[2]uintptr,
just write out a copy of the reflect.methodValue type in the runtime.

Fixes #16331. Fixes #17471.

Change-Id: I81db4d985179b4a81c68c490cceeccbfc675456a
Reviewed-on: https://go-review.googlesource.com/31138
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-10-17 18:57:01 +00:00
Austin Clements
ad5fd2872f test: simplify fixedbugs/issue15747.go
The error check patterns in this test are more complex than necessary
because f2 gets inlined into f1. This behavior isn't important to the
test, so disable inlining of f2 and simplify the error check patterns.

Change-Id: Ia8aee92a52f9217ad71b89b2931494047e8d2185
Reviewed-on: https://go-review.googlesource.com/31132
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-10-15 21:27:45 +00:00
Austin Clements
77527a316b cmd/compile: add go:notinheap type pragma
This adds a //go:notinheap pragma for declarations of types that must
not be heap allocated. We ensure these rules by disallowing new(T),
make([]T), append([]T), or implicit allocation of T, by disallowing
conversions to notinheap types, and by propagating notinheap to any
struct or array that contains notinheap elements.

The utility of this pragma is that we can eliminate write barriers for
writes to pointers to go:notinheap types, since the write barrier is
guaranteed to be a no-op. This will let us mark several scheduler and
memory allocator structures as go:notinheap, which will let us
disallow write barriers in the scheduler and memory allocator much
more thoroughly and also eliminate some problematic hybrid write
barriers.

This also makes go:nowritebarrierrec and go:yeswritebarrierrec much
more powerful. Currently we use go:nowritebarrier all over the place,
but it's almost never what you actually want: when write barriers are
illegal, they're typically illegal for a whole dynamic scope. Partly
this is because go:nowritebarrier has been around longer, but it's
also because go:nowritebarrierrec couldn't be used in situations that
had no-op write barriers or where some nested scope did allow write
barriers. go:notinheap eliminates many no-op write barriers and
go:yeswritebarrierrec makes it possible to opt back in to write
barriers, so these two changes will let us use go:nowritebarrierrec
far more liberally.

This updates #13386, which is about controlling pointers from non-GC'd
memory to GC'd memory. That would require some additional pragma (or
pragmas), but could build on this pragma.

Change-Id: I6314f8f4181535dd166887c9ec239977b54940bd
Reviewed-on: https://go-review.googlesource.com/30939
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-10-15 17:58:14 +00:00
Austin Clements
a9e6cebde2 cmd/compile, runtime: add go:yeswritebarrierrec pragma
This pragma cancels the effect of go:nowritebarrierrec. This is useful
in the scheduler because there are places where we enter a function
without a valid P (and hence cannot have write barriers), but then
obtain a P. This allows us to annotate the function with
go:nowritebarrierrec and split out the part after we've obtained a P
into a go:yeswritebarrierrec function.

Change-Id: Ic8ce4b6d3c074a1ecd8280ad90eaf39f0ffbcc2a
Reviewed-on: https://go-review.googlesource.com/30938
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
2016-10-15 17:58:11 +00:00
Anthony Canino
26c7b4fb1e cmd/compile: "abc"[1] is not an ideal constant
"abc"[1] is not like 'b', in that -"abc"[1] is uint8 math, not ideal constant math.
Delay the constantification until after ideal constant folding is over.

Fixes #11370.

Change-Id: Iba2fc00ca2455959e7bab8f4b8b4aac14b1f9858
Reviewed-on: https://go-review.googlesource.com/15740
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-13 17:41:04 +00:00
Keith Randall
442de98c14 cmd/compile,runtime: redo how map assignments work
To compile:
  m[k] = v
instead of:
  mapassign(maptype, m, &k, &v), do
do:
  *mapassign(maptype, m, &k) = v

mapassign returns a pointer to the value slot in the map.  It is just
like mapaccess except that it will allocate a new slot if k is not
already present in the map.

This makes map accesses faster but potentially larger (codewise).

It is faster because the write into the map is done when the compiler
knows the concrete type, so it can be done with a few store
instructions instead of calling typedmemmove.  We also potentially
avoid stack temporaries to hold v.

The code can be larger when the map has pointers in its value type,
since there is a write barrier call in addition to the mapassign call.
That makes the code at the callsite a bit bigger (go binary is 0.3%
bigger).

This CL is in preparation for doing operations like m[k] += v with
only a single runtime call.  That will roughly double the speed of
such operations.

Update #17133
Update #5147

Change-Id: Ia435f032090a2ed905dac9234e693972fe8c2dc5
Reviewed-on: https://go-review.googlesource.com/30815
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-12 20:41:23 +00:00
Alan Donovan
41a005d458 test: add test for issue 17039
Change-Id: Ieb3d605f03a7185a707621bef7160090c9bdb51f
Reviewed-on: https://go-review.googlesource.com/28873
Reviewed-by: Alan Donovan <adonovan@google.com>
2016-10-12 14:57:26 +00:00
David Chase
f1eed92fd0 cmd/compile: escape analysis needs to run "flood" to fixed point
In some cases the members of the root set from which flood
runs themselves escape, without their referents being also
tagged as escaping.  Fix this by reflooding from those roots
whose escape increases, and also enhance the "leak" test to
include reachability from a heap-escaped root.

Fixes #17318.

Change-Id: Ied1e75cee17ede8ca72a8b9302ce8201641ec593
Reviewed-on: https://go-review.googlesource.com/30693
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2016-10-11 16:32:15 +00:00
Tal Shprecher
672e579444 cmd/compile: avoid leak of dottype expression on double assignment form
This is a followup to issue #13805. That change avoid leaks for types that
don't have any pointers for the single assignment form of a dottype expression.
This does the same for the double assignment form.

Fixes #15796

Change-Id: I27474cade0ff1f3025cb6392f47b87b33542bc0f
Reviewed-on: https://go-review.googlesource.com/24906
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-10-10 12:09:16 +00:00
Wedson Almeida Filho
13c829e5f6 cmd/internal/obj/x86: On amd64, relocation type for and indirect call is pc-relative.
With this change, the code in bug #15609 compiles and runs properly:

0000000000401070 <main.jump>:
  401070:	ff 15 aa 7e 06 00    	callq  *0x67eaa(%rip)        # 468f20 <main.pointer>
  401076:	c3                   	retq

0000000000468f20 g     O .rodata	0000000000000008 main.pointer

Fixes #15609

Change-Id: Iebb4d5a9f9fff335b693f4efcc97882fe04eefd7
Reviewed-on: https://go-review.googlesource.com/22950
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-10-09 19:50:09 +00:00
Keith Randall
f8a0c15e90 test: re-enable live2 test on amd64
Not sure why it was ever disabled (early SSA work?) but it passes now.

Change-Id: I76439cacdbd286ce077f7e08c4d0663396a0cd8f
Reviewed-on: https://go-review.googlesource.com/30672
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-10-07 17:34:02 +00:00
David Chase
c79ba22ece test: delete sliceopt.go
It tests the behavior of the old deleted compiler.

Fixes #17362.

Change-Id: Ia2fdec734c5cbe724a9de562ed71598f67244ab3
Reviewed-on: https://go-review.googlesource.com/30593
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-06 18:19:28 +00:00
Robert Griesemer
936ae27b9c cmd/compile: untyped arrays bounds representable as integers are valid
Fixes #13485.

Change-Id: I11dd15c7d14fc19d42a3b48427a4cc1208b18e6a
Reviewed-on: https://go-review.googlesource.com/30456
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-10-05 22:07:58 +00:00
Robert Griesemer
39055700b1 cmd/compile: ignore struct tags when converting structs
Implementation of spec change https://golang.org/cl/24190/.

For #16085.

Change-Id: Id71ef29af5031b073e8be163f578d1bb768ff97a
Reviewed-on: https://go-review.googlesource.com/30169
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-10-04 17:10:47 +00:00
Keith Randall
6300161d40 cmd/compile: force folding of MOVDaddr into storezero
Fold MOVDaddr ops into MOVXstorezero ops.
Also fold ADDconst into MOVDaddr so we're sure there isn't
(MOVDstorezero (ADDconst (MOVDaddr ..)))

Without this CL, we get:

v1 = MOVDaddr {s}
v2 = VARDEF {s}
v3 = MOVDstorezero v1 v2

The liveness pass thinks the MOVDaddr is a read of s, so s is
incorrectly thought to be live at the start of the function.

Fixes #17194

Change-Id: I2b4a2f13b12aa5b072941ee1c7b89f3793650cdc
Reviewed-on: https://go-review.googlesource.com/30086
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Michael Munday <munday@ca.ibm.com>
2016-10-04 16:10:27 +00:00
Than McIntosh
6c5e377d23 cmd/compile: relax liveness restrictions on ambiguously live
Update gc liveness to remove special conservative treatment
of ambiguously live vars, since there is no longer a need to
protect against GCDEBUG=gcdead.

Change-Id: Id6e2d03218f7d67911e8436d283005a124e6957f
Reviewed-on: https://go-review.googlesource.com/24896
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
2016-10-03 18:07:32 +00:00
Emmanuel Odeke
2d573eee8a cmd/compile: improve error message for wrong number of arguments to return
Fixes #4215.
Fixes #6750.

Improves the error message for wrong number of arguments by comparing
the signature of the return call site arguments, versus the function's
expected return arguments.

In this CL, the signature representation of:
+ ideal numbers(TIDEAL) ie float*, complex*, rune, int is
"number" instead of "untyped number".
+ idealstring is "string" instead of "untyped string".
+ idealbool is "bool" instead of "untyped bool".

However, the representation of other types remains as the compiler
would produce.

* Example 1(in the error messages, if all lines were printed):
$ cat main.go && go run main.go
package main

func foo() (int, int) {
  return 2.3
}

func foo2() {
  return int(2), 2
}

func foo3(v int) (a, b, c, d int) {
  if v >= 5 {
    return 1
  }
  return 2, 3
}

func foo4(name string) (string, int) {
  switch name {
  case "cow":
    return "moo"
  case "dog":
    return "dog", 10, true
  case "fish":
    return ""
  default:
    return "lizard", 10
  }
}

type S int
type T string
type U float64

func foo5() (S, T, U) {
  if false {
    return ""
  } else {
    ptr := new(T)
    return ptr
  }
  return new(S), 12.34, 1 + 0i, 'r', true
}

func foo6() (T, string) {
  return "T"
}

./issue4215.go:4: not enough arguments to return, got (number) want (int, int)
./issue4215.go:8: too many arguments to return, got (int, number) want ()
./issue4215.go:13: not enough arguments to return, got (number) want (int, int, int, int)
./issue4215.go:15: not enough arguments to return, got (number, number) want (int, int, int, int)
./issue4215.go:21: not enough arguments to return, got (string) want (string, int)
./issue4215.go:23: too many arguments to return, got (string, number, bool) want (string, int)
./issue4215.go:25: not enough arguments to return, got (string) want (string, int)
./issue4215.go:37: not enough arguments to return, got (string) want (S, T, U)
./issue4215.go:40: not enough arguments to return, got (*T) want (S, T, U)
./issue4215.go:42: too many arguments to return, got (*S, number, number, number, bool) want (S, T, U)
./issue4215.go:46: not enough arguments to return, got (string) want (T, string)
./issue4215.go:46: too many errors

* Example 2:
$ cat 6750.go && go run 6750.go
package main

import "fmt"

func printmany(nums ...int) {
  for i, n := range nums {
    fmt.Printf("%d: %d\n", i, n)
  }
  fmt.Printf("\n")
}

func main() {
  printmany(1, 2, 3)
  printmany([]int{1, 2, 3}...)
  printmany(1, "abc", []int{2, 3}...)
}
./issue6750.go:15: too many arguments in call to printmany, got (number, string, []int) want (...int)

Change-Id: I6fdce78553ae81770840070e2c975d3e3c83d5d8
Reviewed-on: https://go-review.googlesource.com/25156
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-10-02 16:28:02 +00:00
Matthew Dempsky
03a1dc3522 cmd/compile: don't crash on (unsafe.Sizeof)(0)
Fixes #17270.

Change-Id: I4affa57e10baf1a758bc0977265d160f220b2945
Reviewed-on: https://go-review.googlesource.com/29960
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-09-28 23:13:53 +00:00
Cherry Zhang
4d07d3e29c cmd/compile: re-enable nilcheck removal for newobject
Also add compiler debug ouput and add a test.

Fixes #15390.

Change-Id: Iceba1414c29bcc213b87837387bf8ded1f3157f1
Reviewed-on: https://go-review.googlesource.com/30011
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-09-28 19:41:49 +00:00
Keith Randall
98938189a1 cmd/compile: remove duplicate nilchecks
Mark nil check operations as faulting if their arg is zero.
This lets the late nilcheck pass remove duplicates.

Fixes #17242.

Change-Id: I4c9938d8a5a1e43edd85b4a66f0b34004860bcd9
Reviewed-on: https://go-review.googlesource.com/29952
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2016-09-27 23:54:01 +00:00
Alberto Donizetti
7f1bc53379 cmd/compile: only allow integer expressions as keys in array literals
Fixes #16439
Updates #16679

Change-Id: Idff4b313f29351866b1a649786501adee85fd580
Reviewed-on: https://go-review.googlesource.com/29011
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-09-26 17:49:41 +00:00
Alberto Donizetti
375092bdcb cmd/compile: fix bogus "fallthrough statement out of place"
When processing a fallthrough, the casebody function in swt.go
checks that the last statement has indeed Op == OXFALL (not-processed
fallthrough) before setting it to OFALL (processed fallthrough).

Unfortunately, sometimes the fallthrough statement won't be in the
last node. For example, in

case 0:
	 return func() int {return 1}()
	 fallthrough

the compiler generates

autotmp_0 = (func literal)(); return autotmp_0; fallthrough; <node VARKILL>

with an OVARKILL node in the last position. casebody will find that
last.Op != OXFALL, won't mark the fallthrough as processed, and the
fallthrough line will cause a "fallthrough statement out of place" error.

To fix this, we change casebody so that it searches for the fallthrough
statement backwards in the statements list, without assuming that it'll
be in the last position.

Fixes #13262

Change-Id: I366c6caa7fd7442d365bd7a08cc66a552212d9b2
Reviewed-on: https://go-review.googlesource.com/22921
Run-TryBot: Quentin Smith <quentin@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Quentin Smith <quentin@golang.org>
2016-09-26 15:46:44 +00:00
Cherry Zhang
d586aae1f4 test: errorcheck auto-generated functions
Add an "errorcheckwithauto" action which performs error check
including lines with auto-generated functions (excluded by
default). Comment "// ERRORAUTO" matches these lines.

Add testcase for CL 29570 (as an example).

Updates #16016, #17186.

Change-Id: Iaba3727336cd602f3dda6b9e5f97dafe0848e632
Reviewed-on: https://go-review.googlesource.com/29652
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-09-22 20:10:30 +00:00
Michael Munday
e94c52933b cmd/compile: intrinsify Ctz{32,64} and Bswap{32,64} on s390x
Also adds the 'find leftmost one' instruction (FLOGR) and replaces the
WORD-encoded use of FLOGR in math/big with it.

Change-Id: I18e7cd19e75b8501a6ae8bd925471f7e37ded206
Reviewed-on: https://go-review.googlesource.com/29372
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-19 19:03:01 +00:00
Keith Randall
ca4089ad62 cmd/compile: args no longer live until end-of-function
We're dropping this behavior in favor of runtime.KeepAlive.
Implement runtime.KeepAlive as an intrinsic.

Update #15843

Change-Id: Ib60225bd30d6770ece1c3c7d1339a06aa25b1cbc
Reviewed-on: https://go-review.googlesource.com/28310
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-09-19 16:54:35 +00:00
Keith Randall
6129f37367 cmd/compile: inline convT2{I,E} when result doesn't escape
No point in calling a function when we can build the interface
using a known type (or itab) and the address of a local.

Get rid of third arg (preallocated stack space) to convT2{I,E}.

Makes go binary smaller by 0.2%

benchmark                   old ns/op     new ns/op     delta
BenchmarkEfaceInteger-8     16.7          10.1          -39.52%

Update #17118
Update #15375

Change-Id: I9724a1f802bfa1e3957bf1856b55558278e198a2
Reviewed-on: https://go-review.googlesource.com/29373
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-09-19 02:37:08 +00:00
Trey Lawrence
fc5df089da cmd/compile: fix compiler bug for constant equality comparison
The compiler incorrectly will error when comparing a nil pointer
interface to a nil pointer of any other type. Example:
(*int)(nil) == interface{}(nil)
Will error with "gc: illegal constant expression: *int == interface {}"

Fixes #16702

Change-Id: I1a15d651df2cfca6762b1783a28b377b2e6ff8c6
Reviewed-on: https://go-review.googlesource.com/27591
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-09-17 01:12:24 +00:00
Keith Randall
c199c76cb4 cmd/compile: turn live variable test off for ppc
ppc64 has an extraneous variable live in some situations.
We need a better tighten pass to get rid of this extra variable.
I'm working on it, but fix the test in the meantime.

Fixes build for ppc64.

Change-Id: I1efb9ccb234a64f2a1c228abd2b3195f67fbeb41
Reviewed-on: https://go-review.googlesource.com/29353
Reviewed-by: David Chase <drchase@google.com>
2016-09-16 19:41:42 +00:00
Keith Randall
b265d51789 test,cmd/compile: remove _ssa file suffix
Everything is SSA now.

Update #16357

Change-Id: I436dbe367b863ee81a3695a7d653ba4bfc5b0f6c
Reviewed-on: https://go-review.googlesource.com/29232
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-15 20:47:01 +00:00
Keith Randall
f13701bf2f test: make SSA tests unconditional
Delete legacy backend tests, make SSA tests unconditional.

Next CL will remove _ssa from the file names.

Update #16357

Change-Id: I2a7f5dcbc69455f63b5e6e6b2725df26ab86c8dd
Reviewed-on: https://go-review.googlesource.com/29231
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-15 20:21:26 +00:00
Josh Bleecher Snyder
c9fd997524 cmd/compile: unroll comparisons to short constant strings
Unroll s == "ab" to

len(s) == 2 && s[0] == 'a' && s[1] == 'b'

This generates faster and shorter code
by avoiding a runtime call.
Do something similar for !=.

The cutoff length is 6. This was chosen empirically
by examining binary sizes on arm, arm64, 386, and amd64
using the SSA backend.

For all architectures examined, 4, 5, and 6 were
the ideal cutoff, with identical binary sizes.

The distribution of constant string equality sizes
during 'go build -a std' is:

 40.81%   622 len 0
 14.11%   215 len 4
  9.45%   144 len 1
  7.81%   119 len 3
  7.48%   114 len 5
  5.12%    78 len 7
  4.13%    63 len 2
  3.54%    54 len 8
  2.69%    41 len 6
  1.18%    18 len 10
  0.85%    13 len 9
  0.66%    10 len 14
  0.59%     9 len 17
  0.46%     7 len 11
  0.26%     4 len 12
  0.20%     3 len 19
  0.13%     2 len 13
  0.13%     2 len 15
  0.13%     2 len 16
  0.07%     1 len 20
  0.07%     1 len 23
  0.07%     1 len 33
  0.07%     1 len 36

A cutoff of length 6 covers most of the cases.

Benchmarks on amd64 comparing a string to a constant of length 3:

Cmp/1same-8           4.78ns ± 6%  0.94ns ± 9%  -80.26%  (p=0.000 n=20+20)
Cmp/1diffbytes-8      6.43ns ± 6%  0.96ns ±11%  -85.13%  (p=0.000 n=20+20)
Cmp/3same-8           4.71ns ± 5%  1.28ns ± 5%  -72.90%  (p=0.000 n=20+20)
Cmp/3difffirstbyte-8  6.33ns ± 7%  1.27ns ± 7%  -79.90%  (p=0.000 n=20+20)
Cmp/3difflastbyte-8   6.34ns ± 8%  1.26ns ± 9%  -80.13%  (p=0.000 n=20+20)

The change to the prove test preserves the
existing intent of the test. When the string was
short, there was a new "proved in bounds" report
that referred to individual byte comparisons.

Change-Id: I593ac303b0d11f275672090c5c786ea0c6b8da13
Reviewed-on: https://go-review.googlesource.com/26758
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-09-15 15:37:00 +00:00
Josh Bleecher Snyder
df2b63f09b cmd/compile: unwrap fewer CONVNOPs in staticassign
staticassign unwraps all CONVNOPs.
However, in the included test, we need the
CONVNOP for everything to typecheck.
Stop unwrapping unnecessarily.

The code we generate for this example is
suboptimal, but that's not new; see #17113.

Fixes #17111.

Change-Id: I29532787a074a6fe19a5cc53271eb9c84bf1b576
Reviewed-on: https://go-review.googlesource.com/29213
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-09-15 14:08:10 +00:00
Keith Randall
3134ab3c2d cmd/compile: redo nil checks
Get rid of BlockCheck. Josh goaded me into it, and I went
down a rabbithole making it happen.

NilCheck now panics if the pointer is nil and returns void, as before.
BlockCheck is gone, and NilCheck is no longer a Control value for
any block. It just exists (and deadcode knows not to throw it away).

I rewrote the nilcheckelim pass to handle this case.  In particular,
there can now be multiple NilCheck ops per block.

I moved all of the arch-dependent nil check elimination done as
part of ssaGenValue into its own proper pass, so we don't have to
duplicate that code for every architecture.

Making the arch-dependent nil check its own pass means I needed
to add a bunch of flags to the opcode table so I could write
the code without arch-dependent ops everywhere.

Change-Id: I419f891ac9b0de313033ff09115c374163416a9f
Reviewed-on: https://go-review.googlesource.com/29120
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-09-15 02:42:13 +00:00
Matthew Dempsky
fb273fc3a3 cmd/compile: fix comma-ok assignments for non-boolean ok
Passes toolstash -cmp.

Fixes #16870.

Change-Id: I70dc3bbb3cd3031826e5a54b96ba1ea603c282d1
Reviewed-on: https://go-review.googlesource.com/27910
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2016-09-14 22:11:38 +00:00
Jan Mercl
2e675142dd test/float_lit2: fix expressions in comment
The change corrects the values of the largest float32 value (f1) and the
value of the halfway point between f1 and the next, overflow value (f2).

Fixes #17012

Change-Id: Idaf9997b69d61fafbffdb980d751c9857732e14d
Reviewed-on: https://go-review.googlesource.com/29171
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-09-14 16:39:47 +00:00
Michael Munday
7e2b5a102e test: re-enable phi optimization test
CL 28978 (6ec993a) accidentally disabled the test (it would only
run if amd64 AND s390x, whereas it should be amd64 OR s390x).

Change-Id: I23c1ad71724ff55f5808d5896b19b62c8ec5af76
Reviewed-on: https://go-review.googlesource.com/28981
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-09-13 20:06:13 +00:00
Michael Munday
6ec993adc3 cmd/compile: add SSA backend for s390x and enable by default
The new SSA backend modifies the ABI slightly: R0 is now a usable
general purpose register.

Fixes #16677.

Change-Id: I367435ce921e0c7e79e021c80cf8ef5d1d1466cf
Reviewed-on: https://go-review.googlesource.com/28978
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-09-13 19:39:38 +00:00
Cherry Zhang
8ff4260777 cmd/compile: intrinsify Ctz, Bswap on ARM
Atomic ops on ARM are implemented with kernel calls, so they are
not intrinsified.

Change-Id: I0e7cc2e5526ae1a3d24b4b89be1bd13db071f8ef
Reviewed-on: https://go-review.googlesource.com/28977
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-09-12 19:26:31 +00:00
Josh Bleecher Snyder
dfc56a4cd3 cmd/compile: statically initialize some interface values
When possible, emit static data rather than
init functions for interface values.

This:

* cuts 32k off cmd/go
* removes several error values from runtime init
* cuts the size of the image/color/palette compiled package from 103k to 34k
* reduces the time to build the package in #15520 from 8s to 1.5s

Fixes #6289
Fixes #15528

Change-Id: I317112da17aadb180c958ea328ab380f83e640b4
Reviewed-on: https://go-review.googlesource.com/26668
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-09-12 14:31:26 +00:00
Josh Bleecher Snyder
1fe4c81282 cmd/compile: don't crash on complex(0())
Fixes #17038.

Change-Id: Iaf6294361050040830af1d60cd48f263223d9356
Reviewed-on: https://go-review.googlesource.com/28966
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-09-11 20:43:51 +00:00
Cherry Zhang
4354ffd38b cmd/compile: intrinsify Ctz, Bswap, and some atomics on ARM64
Change-Id: Ia5bf72b70e6f6522d6fb8cd050e78f862d37b5ae
Reviewed-on: https://go-review.googlesource.com/27936
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-09-08 19:45:25 +00:00
Keith Randall
83c73a85db cmd/compile: ignore contentEscapes for marking nodes as escaping
Redo of CL 28575 with fixed test.
We're in a pre-KeepAlive world for a bit yet, the old tests
were in a client which was in a post-KeepAlive world.

Change-Id: I114fd630339d761ab3306d1d99718d3cb973678d
Reviewed-on: https://go-review.googlesource.com/28582
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-09-07 06:59:22 +00:00
Brad Fitzpatrick
bdb3b790c6 Revert of cmd/compile: ignore contentEscapes for marking nodes as escaping
Reason for revert: broke the build due to cherrypick;
relies on an unsubmitted parent CL.

Original issue's description:
> cmd/compile: ignore contentEscapes for marking nodes as escaping
> 
> We can still stack allocate and VarKill nodes which don't
> escape but their content does.
> 
> Fixes #16996
> 
> Change-Id: If8aa0fcf2c327b4cb880a3d5af8d213289e6f6bf
> Reviewed-on: https://go-review.googlesource.com/28575
> Run-TryBot: Keith Randall <khr@golang.org>
> TryBot-Result: Gobot Gobot <gobot@golang.org>
> Reviewed-by: David Chase <drchase@google.com>
> 

Change-Id: Ie1a325209de14d70af6acb2d78269b7a0450da7a
Reviewed-on: https://go-review.googlesource.com/28578
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-09-07 03:23:44 +00:00
Keith Randall
923a74ce77 cmd/compile: ignore contentEscapes for marking nodes as escaping
We can still stack allocate and VarKill nodes which don't
escape but their content does.

Fixes #16996

Change-Id: If8aa0fcf2c327b4cb880a3d5af8d213289e6f6bf
Reviewed-on: https://go-review.googlesource.com/28575
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-09-07 02:07:03 +00:00
David Chase
a6edffb286 cmd/compile: add BVC/BVS to branch ops in ppc64/prog.go
Includes test case shown to fail with unpatched compiler.

Fixes #17005.

Change-Id: I49b7b1a3f02736d85846a2588018b73f68d50320
Reviewed-on: https://go-review.googlesource.com/28573
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
2016-09-07 01:30:34 +00:00
David Chase
0e0ab20334 cmd/compile: remove ld/st-followed nil checks for PPC64
Enabled checks (except for DUFF-ops which aren't implemented yet).
Added ppc64le to relevant test.

Also updated register list to reflect no-longer-reserved-
for-constants status (file was missed in that change).

Updates #16010.

Change-Id: I31b1aac19e14994f760f2ecd02edbeb1f78362e7
Reviewed-on: https://go-review.googlesource.com/28548
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2016-09-06 18:52:13 +00:00
Cherry Zhang
644c16c76c cmd/compile: fix intrinsifying sync/atomic.Swap* on AMD64
It should alias to Xchg instead of Swap. Found when testing #16985.

Change-Id: If9fd734a1f89b8b2656f421eb31b9d1b0d95a49f
Reviewed-on: https://go-review.googlesource.com/28512
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-09-06 14:44:50 +00:00
Cherry Zhang
f1ef5a06d2 cmd/compile: mark some AMD64 atomic ops as clobberFlags
Fixes #16985.

Change-Id: I5954db28f7b70dd3ac7768e471d5df871a5b20f9
Reviewed-on: https://go-review.googlesource.com/28510
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-09-06 14:26:18 +00:00
Josh Bleecher Snyder
be8a1c6139 test: add test for issue 15895
It was fixed earlier in the Go 1.8 cycle.
Add a test.

Fixes #15895

Change-Id: I5834831235d99b9fcf21b435932cdd7ac6dc2c6e
Reviewed-on: https://go-review.googlesource.com/28476
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-04 00:15:41 +00:00
Martin Möhrmann
8895a99c9f cmd/compile: disallow typed non-integer constant len and cap make arguments
make(T, n, m) returns a slice of type T with length n and capacity m
where "The size arguments n and m must be of integer type or untyped."
https://tip.golang.org/ref/spec#Making_slices_maps_and_channels

The failure to reject typed non-integer size arguments in make
during compile time was uncovered after https://golang.org/cl/27851
changed the generation of makeslice calls.

Fixes   #16940
Updates #16949

Change-Id: Ib1e3576f0e6ad199c9b16b7a50c2db81290c63b4
Reviewed-on: https://go-review.googlesource.com/28301
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2016-09-01 20:29:03 +00:00