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3238 Commits

Author SHA1 Message Date
Keith Randall
1fb596143c cmd/compile: don't bother compiling functions named "_"
They can't be used, so we don't need code generated for them. We just
need to report errors in their bodies.

This is the minimal CL for 1.12. For 1.13, CL 158845 will remove
a bunch of special cases sprinkled about the compiler to handle "_"
functions, which should (after this CL) be unnecessary.

Update #29870

Change-Id: Iaa1c194bd0017dffdce86589fe2d36726ee83c13
Reviewed-on: https://go-review.googlesource.com/c/158820
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2019-01-22 22:06:11 +00:00
Keith Randall
462e90259a runtime: keep FuncForPC from crashing for PCs between functions
Reuse the strict mechanism from FileLine for FuncForPC, so we don't
crash when asking the pcln table about bad pcs.

Fixes #29735

Change-Id: Iaffb32498b8586ecf4eae03823e8aecef841aa68
Reviewed-on: https://go-review.googlesource.com/c/157799
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2019-01-14 23:37:39 +00:00
Keith Randall
7502ed3b90 cmd/compile: when merging instructions, prefer line number of faulting insn
Normally this happens when combining a sign extension and a load.  We
want the resulting combo-instruction to get the line number of the
load, not the line number of the sign extension.

For each rule, compute where we should get its line number by finding
a value on the match side that can fault.  Use that line number for
all the new values created on the right-hand side.

Fixes #27201

Change-Id: I19b3c6f468fff1a3c0bfbce2d6581828557064a3
Reviewed-on: https://go-review.googlesource.com/c/156937
Reviewed-by: David Chase <drchase@google.com>
2019-01-14 22:41:33 +00:00
Austin Clements
a2e79571a9 cmd/compile: separate data and function LSyms
Currently, obj.Ctxt's symbol table does not distinguish between ABI0
and ABIInternal symbols. This is *almost* okay, since a given symbol
name in the final object file is only going to belong to one ABI or
the other, but it requires that the compiler mark a Sym as being a
function symbol before it retrieves its LSym. If it retrieves the LSym
first, that LSym will be created as ABI0, and later marking the Sym as
a function symbol won't change the LSym's ABI.

Marking a Sym as a function symbol before looking up its LSym sounds
easy, except Syms have a dual purpose: they are used just as interned
strings (every function, variable, parameter, etc with the same
textual name shares a Sym), and *also* to store state for whatever
package global has that name. As a result, it's easy to slip up and
look up an LSym when a Sym is serving as the name of a local variable,
and then later mark it as a function when it's serving as the global
with the name.

In general, we were careful to avoid this, but #29610 demonstrates one
case where we messed up. Because of on-demand importing from indexed
export data, it's possible to compile a method wrapper for a type
imported from another package before importing an init function from
that package. If the argument of the method is named "init", the
"init" LSym will be created as a data symbol when compiling the
wrapper, before it gets marked as a function symbol.

To fix this, we separate obj.Ctxt's symbol tables for ABI0 and
ABIInternal symbols. This way, the compiler will simply get a
different LSym once the Sym takes on its package-global meaning as a
function.

This fixes the above ordering issue, and means we no longer need to go
out of our way to create the "init" function early and mark it as a
function symbol.

Fixes #29610.
Updates #27539.

Change-Id: Id9458b40017893d46ef9e4a3f9b47fc49e1ce8df
Reviewed-on: https://go-review.googlesource.com/c/157017
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2019-01-11 00:45:49 +00:00
Keith Randall
956879dd0b runtime: make FuncForPC return the innermost inlined frame
Returning the innermost frame instead of the outermost
makes code that walks the results of runtime.Caller{,s}
still work correctly in the presence of mid-stack inlining.

Fixes #29582

Change-Id: I2392e3dd5636eb8c6f58620a61cef2194fe660a7
Reviewed-on: https://go-review.googlesource.com/c/156364
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2019-01-08 21:54:04 +00:00
David Chase
28fb8c6987 cmd/compile: modify swt.go to skip repeated walks of switch
The compiler appears to contain several squirrelly corner
cases where nodes are double walked, some where new nodes
are created from walked parts.  Rather than trust that we
had searched hard enough for the last one, change
exprSwitch.walk() to return immediately if it has already
been walked.  This appears to be the only case where
double-walking a node is actually harmful.

Fixes #29562.

Change-Id: I0667e8769aba4c3236666cd836a934e256c0bfc5
Reviewed-on: https://go-review.googlesource.com/c/156317
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2019-01-04 21:51:37 +00:00
Keith Randall
af134b17da runtime: proper panic tracebacks with mid-stack inlining
As a followon to CL 152537, modify the panic-printing traceback
to also handle mid-stack inlining correctly.

Also declare -fm functions (aka method functions) as wrappers, so that
they get elided during traceback. This fixes part 2 of #26839.

Fixes #28640
Fixes #24488
Update #26839

Change-Id: I1c535a9b87a9a1ea699621be1e6526877b696c21
Reviewed-on: https://go-review.googlesource.com/c/153477
Reviewed-by: David Chase <drchase@google.com>
2019-01-04 00:00:24 +00:00
Keith Randall
688667716e runtime: don't scan go'd function args past length of ptr bitmap
Use the length of the bitmap to decide how much to pass to the
write barrier, not the total length of the arguments.

The test needs enough arguments so that two distinct bitmaps
get interpreted as a single longer bitmap.

Update #29362

Change-Id: I78f3f7f9ec89c2ad4678f0c52d3d3def9cac8e72
Reviewed-on: https://go-review.googlesource.com/c/156123
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2019-01-03 23:37:42 +00:00
Keith Randall
af4320350b runtime: add test for go function argument scanning
Derived	from Naoki's reproducer.

Update #29362

Change-Id: I1cbd33b38a2f74905dbc22c5ecbad4a87a24bdd1
Reviewed-on: https://go-review.googlesource.com/c/156122
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2019-01-03 20:17:01 +00:00
Cherry Zhang
2e217fa726 cmd/compile: fix deriving from x+d >= w on overflow in prove pass
In the case of x+d >= w, where d and w are constants, we are
deriving x is within the bound of min=w-d and max=maxInt-d. When
there is an overflow (min >= max), we know only one of x >= min
or x <= max is true, and we derive this by excluding the other.
When excluding x >= min, we did not consider the equal case, so
we could incorrectly derive x <= max when x == min.

Fixes #29502.

Change-Id: Ia9f7d814264b1a3ddf78f52e2ce23377450e6e8a
Reviewed-on: https://go-review.googlesource.com/c/156019
Reviewed-by: David Chase <drchase@google.com>
2019-01-02 19:28:06 +00:00
Alberto Donizetti
efbd01f1dc test: disable issue 29329 test when cgo is not enabled
CL 155917 added a -race test that shouldn't be run when cgo is not
enabled. Enforce this in the test file, with a buildflag.

Fixes the nocgo builder.

Change-Id: I9fe0d8f21da4d6e2de3f8fe9395e1fa7e9664b02
Reviewed-on: https://go-review.googlesource.com/c/155957
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-12-29 14:18:11 +00:00
Keith Randall
ed15e82413 runtime: panic on uncomparable map key, even if map is empty
Reorg map flags a bit so we don't need any extra space for the extra flag.

Fixes #23734

Change-Id: I436812156240ae90de53d0943fe1aabf3ea37417
Reviewed-on: https://go-review.googlesource.com/c/155918
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-12-29 01:00:54 +00:00
Keith Randall
14bdcc76fd cmd/compile: fix racewalk{enter,exit} removal
We can't remove race instrumentation unless there are no calls,
not just no static calls. Closure and interface calls also count.

The problem in issue 29329 is that there was a racefuncenter, an
InterCall, and a racefuncexit.  The racefuncenter was removed, then
the InterCall was rewritten to a StaticCall. That prevented the
racefuncexit from being removed. That caused an imbalance in
racefuncenter/racefuncexit calls, which made the race detector barf.

Bug introduced at CL 121235

Fixes #29329

Change-Id: I2c94ac6cf918dd910b74b2a0de5dc2480d236f16
Reviewed-on: https://go-review.googlesource.com/c/155917
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-12-29 00:04:59 +00:00
Keith Randall
69c2c56453 cmd/compile,runtime: redo mid-stack inlining tracebacks
Work involved in getting a stack trace is divided between
runtime.Callers and runtime.CallersFrames.

Before this CL, runtime.Callers returns a pc per runtime frame.
runtime.CallersFrames is responsible for expanding a runtime frame
into potentially multiple user frames.

After this CL, runtime.Callers returns a pc per user frame.
runtime.CallersFrames just maps those to user frame info.

Entries in the result of runtime.Callers are now pcs
of the calls (or of the inline marks), not of the instruction
just after the call.

Fixes #29007
Fixes #28640
Update #26320

Change-Id: I1c9567596ff73dc73271311005097a9188c3406f
Reviewed-on: https://go-review.googlesource.com/c/152537
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2018-12-28 20:55:36 +00:00
Cherry Zhang
6a64efc250 cmd/compile: fix MIPS SGTconst-with-shift rules
(SGTconst [c] (SRLconst _ [d])) && 0 <= int32(c) && uint32(d) <= 31 && 1<<(32-uint32(d)) <= int32(c) -> (MOVWconst [1])

This rule is problematic. 1<<(32-uint32(d)) <= int32(c) meant to
say that it is true if c is greater than the largest possible
value of the right shift. But when d==1, 1<<(32-1) is negative
and results in the wrong comparison.

Rewrite the rules in a more direct way.

Fixes #29402.

Change-Id: I5940fc9538d9bc3a4bcae8aa34672867540dc60e
Reviewed-on: https://go-review.googlesource.com/c/155798
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2018-12-27 00:07:53 +00:00
Keith Randall
c5414457c6 cmd/compile: pad zero-sized stack variables
If someone takes a pointer to a zero-sized stack variable, it can
be incorrectly interpreted as a pointer to the next object in the
stack frame. To avoid this, add some padding after zero-sized variables.

We only need to pad if the next variable in memory (which is the
previous variable in the order in which we allocate variables to the
stack frame) has pointers. If the next variable has no pointers, it
won't hurt to have a pointer to it.

Because we allocate all pointer-containing variables before all
non-pointer-containing variables, we should only have to pad once per
frame.

Fixes #24993

Change-Id: Ife561cdfdf964fdbf69af03ae6ba97d004e6193c
Reviewed-on: https://go-review.googlesource.com/c/155698
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-12-22 01:16:00 +00:00
Keith Randall
debca77971 cmd/compile: fix line number for implicitly declared method expressions
Method expressions where the method is implicitly declared have no
line number. The Error method of the built-in error type is one such
method.  We leave the line number at the use of the method expression
in this case.

Fixes #29389

Change-Id: I29c64bb47b1a704576abf086599eb5af7b78df53
Reviewed-on: https://go-review.googlesource.com/c/155639
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-12-22 01:08:39 +00:00
Matthew Dempsky
706b54bb85 cmd/compile: fix ICE due to bad rune width
It was possible that

    var X interface{} = 'x'

could cause a compilation failure due to having not calculated rune's
width yet. typecheck.go normally calculates the width of things, but
it doesn't for implicit conversions to default type. We already
compute the width of all of the standard numeric types in universe.go,
but we failed to calculate it for the rune alias type. So we could
later crash if the code never otherwise explicitly mentioned 'rune'.

While here, explicitly compute widths for 'byte' and 'error' for
consistency.

Fixes #29350.

Change-Id: Ifedd4899527c983ee5258dcf75aaf635b6f812f8
Reviewed-on: https://go-review.googlesource.com/c/155380
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
2018-12-20 19:35:04 +00:00
Keith Randall
443990742e cmd/compile: ignore out-of-bounds reads from readonly constants
Out-of-bounds reads of globals can happen in dead code. For code
like this:

s := "a"
if len(s) == 3 {
   load s[0], s[1], and s[2]
}

The out-of-bounds loads are dead code, but aren't removed yet
when lowering. We need to not panic when compile-time evaluating
those loads. This can only happen for dead code, so the result
doesn't matter.

Fixes #29215

Change-Id: I7fb765766328b9524c6f2a1e6ab8d8edd9875097
Reviewed-on: https://go-review.googlesource.com/c/154057
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>
2018-12-20 17:34:32 +00:00
Robert Griesemer
99e4ddd053 cmd/compile: increase nesting depth limit for type descriptors
The formatting routines for types use a depth limit as primitive
mechanism to detect cycles. For now, increase the limit from 100
to 250 and file #29312 so we don't drop this on the floor.

Also, adjust some fatal error messages elsewhere to use
better formatting.

Fixes #29264.
Updates #29312.

Change-Id: Idd529f6682d478e0dcd2d469cb802192190602f6
Reviewed-on: https://go-review.googlesource.com/c/154583
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-12-18 00:13:58 +00:00
David Chase
d924c3336c cmd/compile: prevent double-walk of switch for OPRINT/OPRINTN
When a println arg contains a call to an inlineable function
that itself contains a switch, that switch statement will be
walked twice, once by the walkexprlist formerly in the
OPRINT/OPRINTN case, then by walkexprlistcheap in walkprint.

Remove the first walkexprlist, it is not necessary.
walkexprlist =
		s[i] = walkexpr(s[i], init)
walkexprlistcheap = {
		s[i] = cheapexpr(n, init)
		s[i] = walkexpr(s[i], init)
}

Seems like this might be possible in other places, i.e.,
calls to inlineable switch-containing functions.

See also #25776.
Fixes #29220.

Change-Id: I3781e86aad6688711597b8bee9bc7ebd3af93601
Reviewed-on: https://go-review.googlesource.com/c/154497
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2018-12-17 22:49:21 +00:00
Robert Griesemer
a1aafd8b28 cmd/compile: generate interface method expression wrapper for error.Error
A prior optimization (https://golang.org/cl/106175) removed the
generation of unnecessary method expression wrappers, but also
eliminated the generation of the wrapper for error.Error which
was still required.

Special-case error type in the optimization.

Fixes #29304.

Change-Id: I54c8afc88a2c6d1906afa2d09c68a0a3f3e2f1e3
Reviewed-on: https://go-review.googlesource.com/c/154578
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-12-17 19:48:36 +00:00
Martin Möhrmann
38e7177c94 cmd/compile: fix length overflow when appending elements to a slice
Instead of testing len(slice)+numNewElements > cap(slice) use
uint(len(slice)+numNewElements) > uint(cap(slice)) to test
if a slice needs to be grown in an append operation.

This prevents a possible overflow when len(slice) is near the maximum
int value and the addition of a constant number of new elements
makes it overflow and wrap around to a negative number which is
smaller than the capacity of the slice.

Appending a slice to a slice with append(s1, s2...) already used
a uint comparison to test slice capacity and therefore was not
vulnerable to the same overflow issue.

Fixes: #29190

Change-Id: I41733895838b4f80a44f827bf900ce931d8be5ca
Reviewed-on: https://go-review.googlesource.com/c/154037
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-12-14 05:48:18 +00:00
Keith Randall
05bbec7357 cmd/compile: don't combine load+op if the op has SymAddr arguments
By combining the load+op, we may force the op to happen earlier in
the store chain. That might force the SymAddr operation earlier, and
in particular earlier than its corresponding VarDef. That leads to
an invalid schedule, so avoid that.

This is kind of a hack to work around the issue presented. I think
the underlying problem, that LEAQ is not directly ordered with respect
to its vardef, is the real problem. The benefit of this CL is that
it fixes the immediate issue, is small, and obviously won't break
anything. A real fix for this issue is much more invasive.

The go binary is unchanged in size.
This situation just doesn't occur very often.

Fixes #28445

Change-Id: I13a765e13f075d5b6808a355ef3c43cdd7cd47b6
Reviewed-on: https://go-review.googlesource.com/c/153641
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2018-12-12 21:13:15 +00:00
Keith Randall
01a1eaa10c cmd/compile: use innermost line number for -S
When functions are inlined, for instructions in the inlined body, does
-S print the location of the call, or the location of the body? Right
now, we do the former. I'd like to do the latter by default, it makes
much more sense when reading disassembly. With mid-stack inlining
enabled in more cases, this quandry will come up more often.

The original behavior is still available with -S=2. Some tests
use this mode (so they can find assembly generated by a particular
source line).

This helped me with understanding what the compiler was doing
while fixing #29007.

Change-Id: Id14a3a41e1b18901e7c5e460aa4caf6d940ed064
Reviewed-on: https://go-review.googlesource.com/c/153241
Reviewed-by: David Chase <drchase@google.com>
2018-12-11 20:24:45 +00:00
David Chase
ea6259d5e9 cmd/compile: check for negative upper bound to IsSliceInBounds
IsSliceInBounds(x, y) asserts that y is not negative, but
there were cases where this is not true.  Change code
generation to ensure that this is true when it's not obviously
true.  Prove phase cleans a few of these out.

With this change the compiler text section is 0.06% larger,
that is, not very much.  Benchmarking still TBD, may need
to wait for access to a benchmarking box (next week).

Also corrected run.go to handle '?' in -update_errors output.

Fixes #28797.

Change-Id: Ia8af90bc50a91ae6e934ef973def8d3f398fac7b
Reviewed-on: https://go-review.googlesource.com/c/152477
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-12-07 23:04:58 +00:00
Austin Clements
6454a09a97 cmd/compile: omit write barriers for slice clears of go:notinheap pointers
Currently,

  for i := range a {
    a[i] = nil
  }

will compile to have write barriers even if a is a slice of pointers
to go:notinheap types. This happens because the optimization that
transforms this into a memclr only asks it a's element type has
pointers, and not if it specifically has heap pointers.

Fix this by changing arrayClear to use HasHeapPointer instead of
types.Haspointers. We probably shouldn't have both of these functions,
since a pointer to a notinheap type is effectively a uintptr, but
that's not going to change in this CL.

Change-Id: I284b85bdec6ae1e641f894e8f577989facdb0cf1
Reviewed-on: https://go-review.googlesource.com/c/152723
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2018-12-05 21:54:54 +00:00
Robert Griesemer
cd47e8944d cmd/compile: avoid multiple errors regarding misuse of ... in signatures
Follow-up on #28450 (golang.org/cl/152417).

Updates #28450.
Fixes #29107.

Change-Id: Ib4b4fe582c35315a4f71cf6dbc7f7f2f24b37ec1
Reviewed-on: https://go-review.googlesource.com/c/152758
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2018-12-05 20:59:58 +00:00
smasher164
a7af474359 cmd/compile: improve error message for non-final variadic parameter
Previously, when a function signature had defined a non-final variadic
parameter, the error message always referred to the type associated with that
parameter. However, if the offending parameter's name was part of an identifier
list with a variadic type, one could misinterpret the message, thinking the
problem had been with one of the other names in the identifer list.

    func bar(a, b ...int) {}
clear ~~~~~~~^       ^~~~~~~~ confusing

This change updates the error message and sets the column position to that of
the offending parameter's name, if it exists.

Fixes #28450.

Change-Id: I076f560925598ed90e218c25d70f9449ffd9b3ea
Reviewed-on: https://go-review.googlesource.com/c/152417
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
2018-12-05 01:35:59 +00:00
Cherry Zhang
be09bdf589 cmd/compile: fix unnamed parameter handling in escape analysis
For recursive functions, the parameters were iterated using
fn.Name.Defn.Func.Dcl, which does not include unnamed/blank
parameters. This results in a mismatch in formal-actual
assignments, for example,

func f(_ T, x T)

f(a, b) should result in { _=a, x=b }, but the escape analysis
currently sees only { x=a } and drops b on the floor. This may
cause b to not escape when it should (or a escape when it should
not).

Fix this by using fntype.Params().FieldSlice() instead, which
does include unnamed parameters.

Also add a sanity check that ensures all the actual parameters
are consumed.

Fixes #29000

Change-Id: Icd86f2b5d71e7ebbab76e375b7702f62efcf59ae
Reviewed-on: https://go-review.googlesource.com/c/152617
Reviewed-by: Keith Randall <khr@golang.org>
2018-12-04 23:01:00 +00:00
Keith Randall
4a1a783dda cmd/compile: fix static initializer
staticcopy of a struct or array should recursively call itself, not
staticassign.

This fixes an issue where a struct with a slice in it is copied during
static initialization. In this case, the backing array for the slice
is duplicated, and each copy of the slice refers to a different
backing array, which is incorrect.  That issue has existed since at
least Go 1.2.

I'm not sure why this was never noticed. It seems like a pretty
obvious bug if anyone modifies the resulting slice.

In any case, we started to notice when the optimization in CL 140301
landed.  Here is basically what happens in issue29013b.go:
1) The error above happens, so we get two backing stores for what
   should be the same slice.
2) The code for initializing those backing stores is reused.
   But not duplicated: they are the same Node structure.
3) The order pass allocates temporaries for the map operations.
   For the first instance, things work fine and two temporaries are
   allocated and stored in the OKEY nodes. For the second instance,
   the order pass decides new temporaries aren't needed, because
   the OKEY nodes already have temporaries in them.
   But the order pass also puts a VARKILL of the temporaries between
   the two instance initializations.
4) In this state, the code is technically incorrect. But before
   CL 140301 it happens to work because the temporaries are still
   correctly initialized when they are used for the second time. But then...
5) The new CL 140301 sees the VARKILLs and decides to reuse the
   temporary for instance 1 map 2 to initialize the instance 2 map 1
   map. Because the keys aren't re-initialized, instance 2 map 1
   gets the wrong key inserted into it.

Fixes #29013

Change-Id: I840ce1b297d119caa706acd90e1517a5e47e9848
Reviewed-on: https://go-review.googlesource.com/c/152081
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2018-12-03 16:48:21 +00:00
David Chase
624e197c71 cmd/compile: decrease inlining call cost from 60 to 57
A Go user made a well-documented request for a slightly
lower threshold.  I tested against a selection of other
people's benchmarks, and saw a tiny benefit (possibly noise)
at equally tiny cost, and no unpleasant surprises observed
in benchmarking.

I.e., might help, doesn't hurt, low risk, request was
delivered on a silver platter.

It did, however, change the behavior of one test because
now bytes.Buffer.Grow is eligible for inlining.

Updates #19348.

Change-Id: I85e3088a4911290872b8c6bda9601b5354c48695
Reviewed-on: https://go-review.googlesource.com/c/151977
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2018-12-01 15:03:28 +00:00
Ben Shi
c042fedbc8 test/codegen: add arithmetic tests for 386/amd64/arm/arm64
This CL adds several test cases of arithmetic operations for
386/amd64/arm/arm64.

Change-Id: I362687c06249f31091458a1d8c45fc4d006b616a
Reviewed-on: https://go-review.googlesource.com/c/151897
Run-TryBot: Ben Shi <powerman1st@163.com>
Reviewed-by: Keith Randall <khr@golang.org>
2018-12-01 05:17:44 +00:00
Robert Griesemer
a37d95c74a cmd/compile: fix constant index bounds check and error message
While here, rename nonnegintconst to indexconst (because that's
what it is) and add Fatalf calls where we are not expecting the
indexconst call to fail, and fixed wrong comparison in smallintconst.

Fixes #23781.

Change-Id: I86eb13081c450943b1806dfe3ae368872f76639a
Reviewed-on: https://go-review.googlesource.com/c/151599
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2018-11-30 23:48:00 +00:00
Keith Randall
2140975ebd cmd/compile: eliminate write barriers when writing non-heap ptrs
We don't need a write barrier if:
1) The location we're writing to doesn't hold a heap pointer, and
2) The value we're writing isn't a heap pointer.

The freshly returned value from runtime.newobject satisfies (1).
Pointers to globals, and the contents of the read-only data section satisfy (2).

This is particularly helpful for code like:
p := []string{"abc", "def", "ghi"}

Where the compiler generates:
   a := new([3]string)
   move(a, statictmp_)  // eliminates write barriers here
   p := a[:]

For big slice literals, this makes the code a smaller and faster to
compile.

Update #13554. Reduces the compile time by ~10% and RSS by ~30%.

Change-Id: Icab81db7591c8777f68e5d528abd48c7e44c87eb
Reviewed-on: https://go-review.googlesource.com/c/151498
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2018-11-29 22:23:02 +00:00
Keith Randall
2b4f24a2d2 cmd/compile: randomize value order in block for testing
A little bit of compiler stress testing. Randomize the order
of the values in a block before every phase. This randomization
makes sure that we're not implicitly depending on that order.

Currently the random seed is a hash of the function name.
It provides determinism, but sacrifices some coverage.
Other arrangements are possible (env var, ...) but require
more setup.

Fixes #20178

Change-Id: Idae792a23264bd9a3507db6ba49b6d591a608e83
Reviewed-on: https://go-review.googlesource.com/c/33909
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2018-11-28 17:13:46 +00:00
Keith Randall
0b79dde112 cmd/compile: don't use CMOV ops to compute load addresses
We want to issue loads as soon as possible, especially when they
are going to miss in the cache. Using a conditional move (CMOV) here:

i := ...
if cond {
   i++
}
... = a[i]

means that we have to wait for cond to be computed before the load
is issued. Without a CMOV, if the branch is predicted correctly the
load can be issued in parallel with computing cond.
Even if the branch is predicted incorrectly, maybe the speculative
load is close to the real load, and we get a prefetch for free.
In the worst case, when the prediction is wrong and the address is
way off, we only lose by the time difference between the CMOV
latency (~2 cycles) and the mispredict restart latency (~15 cycles).

We only squash CMOVs that affect load addresses. Results of CMOVs
that are used for other things (store addresses, store values) we
use as before.

Fixes #26306

Change-Id: I82ca14b664bf05e1d45e58de8c4d9c775a127ca1
Reviewed-on: https://go-review.googlesource.com/c/145717
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2018-11-27 17:22:37 +00:00
Clément Chigot
5680874e0c test: fix nilptr5 for AIX
This commit fixes a mistake made in CL 144538.
This nilcheck can be removed because OpPPC64LoweredMove will fault if
arg0 is nil, as it's used to store. Further information can be found in
cmd/compile/internal/ssa/nilcheck.go.

Change-Id: Ifec0080c00eb1f94a8c02f8bf60b93308e71b119
Reviewed-on: https://go-review.googlesource.com/c/151298
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-11-27 15:36:08 +00:00
Brian Kessler
319787a528 cmd/compile: intrinsify math/bits.Div on amd64
Note that the intrinsic implementation panics separately for overflow and
divide by zero, which matches the behavior of the pure go implementation.
There is a modest performance improvement after intrinsic implementation.

name     old time/op  new time/op  delta
Div-4    53.0ns ± 1%  47.0ns ± 0%  -11.28%  (p=0.008 n=5+5)
Div32-4  18.4ns ± 0%  18.5ns ± 1%     ~     (p=0.444 n=5+5)
Div64-4  53.3ns ± 0%  47.5ns ± 4%  -10.77%  (p=0.008 n=5+5)

Updates #28273

Change-Id: Ic1688ecc0964acace2e91bf44ef16f5fb6b6bc82
Reviewed-on: https://go-review.googlesource.com/c/144378
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2018-11-27 05:04:25 +00:00
Keith Randall
eb6c433eb3 cmd/compile: don't convert non-Go-constants to OLITERALs
Don't convert values that aren't Go constants, like
uintptr(unsafe.Pointer(nil)), to a literal constant. This avoids
assuming they are constants for things like indexing, array sizes,
case duplication, etc.

Also, nil is an allowed duplicate in switches. CTNILs aren't Go constants.

Fixes #28078
Fixes #28079

Change-Id: I9ab8af47098651ea09ef10481787eae2ae2fb445
Reviewed-on: https://go-review.googlesource.com/c/151320
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-11-27 01:21:41 +00:00
Keith Randall
6fff980cf1 cmd/compile: initialize sparse slice literals dynamically
When a slice composite literal is sparse, initialize it dynamically
instead of statically.

s := []int{5:5, 20:20}

To initialize the backing store for s, use 2 constant writes instead
of copying from a static array with 21 entries.

This CL also fixes pathologies in the compiler when the slice is
*very* sparse.

Fixes #23780

Change-Id: Iae95c6e6f6a0e2994675cbc750d7a4dd6436b13b
Reviewed-on: https://go-review.googlesource.com/c/151319
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-11-26 22:50:48 +00:00
Keith Randall
1602e49701 cmd/compile: don't constant-fold non-Go constants in the frontend
Abort evconst if its argument isn't a Go constant. The SSA backend
will do the optimizations in question later. They tend to be weird
cases, like uintptr(unsafe.Pointer(uintptr(1))).

Fix OADDSTR and OCOMPLEX cases in isGoConst.
OADDSTR has its arguments in n.List, not n.Left and n.Right.
OCOMPLEX might have a 2-result function as its arg in List[0]
(in which case it isn't a Go constant).

Fixes #24760

Change-Id: Iab312d994240d99b3f69bfb33a443607e872b01d
Reviewed-on: https://go-review.googlesource.com/c/151338
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2018-11-26 22:49:57 +00:00
Keith Randall
ca3749230b cmd/compile: allow bodyless function if it is linkname'd
In assembly free packages (aka "complete" or "pure go"), allow
bodyless functions if they are linkname'd to something else.

Presumably the thing the function is linkname'd to has a definition.
If not, the linker will complain. And linkname is unsafe, so we expect
users to know what they are doing.

Note this handles only one direction, where the linkname directive
is in the local package. If the linkname directive is in the remote
package, this CL won't help. (See os/signal/sig.s for an example.)

Fixes #23311

Change-Id: I824361b4b582ee05976d94812e5b0e8b0f7a18a6
Reviewed-on: https://go-review.googlesource.com/c/151318
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2018-11-26 20:00:59 +00:00
Clément Chigot
9fe9853ae5 cmd/compile: fix nilcheck for AIX
This commit adapts compile tool to create correct nilchecks for AIX.

AIX allows to load a nil pointer. Therefore, the default nilcheck
which issues a load must be replaced by a CMP instruction followed by a
store at 0x0 if the value is nil. The store will trigger a SIGSEGV as on
others OS.

The nilcheck algorithm must be adapted to do not remove nilcheck if it's
only a read. Stores are detected with v.Type.IsMemory().

Tests related to nilptr must be adapted to the previous changements.
nilptr.go cannot be used as it's because the AIX address space starts at
1<<32.

Change-Id: I9f5aaf0b7e185d736a9b119c0ed2fe4e5bd1e7af
Reviewed-on: https://go-review.googlesource.com/c/144538
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2018-11-26 14:13:53 +00:00
Clément Chigot
041526c6ef runtime: handle 64bits addresses for AIX
This commit allows the runtime to handle 64bits addresses returned by
mmap syscall on AIX.

Mmap syscall returns addresses on 59bits on AIX. But the Arena
implementation only allows addresses with less than 48 bits.
This commit increases the arena size up to 1<<60 for aix/ppc64.

Update: #25893

Change-Id: Iea72e8a944d10d4f00be915785e33ae82dd6329e
Reviewed-on: https://go-review.googlesource.com/c/138736
Reviewed-by: Austin Clements <austin@google.com>
2018-11-26 14:06:28 +00:00
Austin Clements
9255688610 cmd/asm: rename -symabis to -gensymabis
Currently, both asm and compile have a -symabis flag, but in asm it's
a boolean flag that means to generate a symbol ABIs file and in the
compiler its a string flag giving the path of the symbol ABIs file to
consume. I'm worried about this false symmetry biting us in the
future, so rename asm's flag to -gensymabis.

Updates #27539.

Change-Id: I8b9c18a852d2838099718f8989813f19d82e7434
Reviewed-on: https://go-review.googlesource.com/c/149818
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2018-11-16 21:57:50 +00:00
Martin Möhrmann
75798e8ada runtime: make processor capability variable naming platform specific
The current support_XXX variables are specific for the
amd64 and 386 platforms.

Prefix processor capability variables by architecture to have a
consistent naming scheme and avoid reuse of the existing
variables for new platforms.

This also aligns naming of runtime variables closer with internal/cpu
processor capability variable names.

Change-Id: I3eabb29a03874678851376185d3a62e73c1aff1d
Reviewed-on: https://go-review.googlesource.com/c/91435
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2018-11-14 20:30:31 +00:00
Milan Knezevic
c92e73b702 cmd/compile/internal/gc: OMUL should be evaluated when using soft-float
When using soft-float, OMUL might be rewritten to function call
so we should ensure it was evaluated first.

Fixes #28688

Change-Id: I30b87501782fff62d35151f394a1c22b0d490c6c
Reviewed-on: https://go-review.googlesource.com/c/148837
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2018-11-14 18:52:15 +00:00
Emmanuel T Odeke
6d620fc42e test: move empty header file in builddir, buildrundir to temp directory
Move the empty header file created by "builddir", "buildrundir"
directives to t.tempDir. The file was accidentally placed in the
same directory as the source code and this was a vestige of CL 146999.

Fixes #28781

Change-Id: I3d2ada5f9e8bf4ce4f015b9bd379b311592fe3ce
Reviewed-on: https://go-review.googlesource.com/c/149458
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2018-11-14 00:22:40 +00:00
Austin Clements
a3c70e28ed test: fix ABI mismatch in fixedbugs/issue19507
Because run.go doesn't pass the package being compiled to the compiler
via the -p flag, it can't match up the main·f symbol from the
assembler with the "func f" stub in Go, so it doesn't produce the
correct assembly stub.

Fix this by removing the package prefix from the assembly definition.

Alternatively, we could make run.go pass -p to the compiler, but it's
nicer to remove these package prefixes anyway.

Should fix the linux-arm builder, which was broken by the introduction
of function ABIs in CL 147160.

Updates #27539.

Change-Id: Id62b7701e1108a21a5ad48ffdb5dad4356c273a6
Reviewed-on: https://go-review.googlesource.com/c/149483
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
2018-11-13 23:44:52 +00:00