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Commit Graph

791 Commits

Author SHA1 Message Date
Russ Cox
d432238fad test: expand issue7863 test
This was sitting in my client but I forgot hg add.

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/101800045
2014-05-27 21:53:39 -07:00
Russ Cox
8a2db409c4 cmd/gc: fix race compilation failure 'non-orig name'
CL 51010045 fixed the first one of these:

        cmd/gc: return canonical Node* from temp

        For historical reasons, temp was returning a copy
        of the created Node*, not the original Node*.
        This meant that if analysis recorded information in the
        returned node (for example, n->addrtaken = 1), the
        analysis would not show up on the original Node*, the
        one kept in fn->dcl and consulted during liveness
        bitmap creation.

        Correct this, and watch for it when setting addrtaken.

        Fixes #7083.

        R=khr, dave, minux.ma
        CC=golang-codereviews
        https://golang.org/cl/51010045

CL 53200043 fixed the second:

        cmd/gc: fix race build

        Missed this case in CL 51010045.

        TBR=khr
        CC=golang-codereviews
        https://golang.org/cl/53200043

This CL fixes the third. There are only three nod(OXXX, ...)
calls in sinit.c, so maybe we're done. Embarassing that it
took three CLs to find all three.

Fixes #8028.

LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews, iant
https://golang.org/cl/100800046
2014-05-27 23:59:27 -04:00
Russ Cox
ceb982e004 cmd/gc: fix defer copy(x, <-c)
In the first very rough draft of the reordering code
that was introduced in the Go 1.3 cycle, the pre-allocated
temporary for a ... argument was held in n->right.
It moved to n->alloc but the code avoiding n->right
was left behind in order.c. In copy(x, <-c), the receive
is in n->right and must be processed. Delete the special
case code, removing the bug.

Fixes #8039.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/100820044
2014-05-27 23:59:06 -04:00
Russ Cox
daf9308066 cmd/gc: fix infinite loop in nil check removal
Fixes #8076.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/93610043
2014-05-27 23:58:49 -04:00
Russ Cox
74ce581b06 cmd/gc: fix conversion of runtime constant
The code cannot have worked before, because it was
trying to use the old value in a range check for the new
type, which might have a different representation
(hence the 'internal compiler error').

Fixes #8073.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/98630045
2014-05-27 21:38:19 -04:00
Brad Fitzpatrick
bd401baef2 test: add test for fixed issue 7863
Fixes #7863

LGTM=rsc
R=rsc, ruiu
CC=golang-codereviews
https://golang.org/cl/98610045
2014-05-27 16:01:43 -07:00
Russ Cox
f374dd30a0 test: test issue 7884 (already fixed)
I don't know when the bug was fixed, but empirically it was.
Make sure it stays fixed by adding a test.

Fixes #7884.

LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/93500043
2014-05-20 11:42:25 -04:00
Russ Cox
82854d7b39 syscall: fix Write(nil) on NaCl
Fixes #7050.

LGTM=crawshaw, r
R=golang-codereviews, crawshaw, r
CC=golang-codereviews
https://golang.org/cl/91590043
2014-05-20 11:38:34 -04:00
Russ Cox
a663e0a038 cmd/gc: fix <-<-expr
The temporary-introducing pass was not recursing
into the argumnt of a receive operation.

Fixes #8011.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews, iant, khr
https://golang.org/cl/91540043
2014-05-19 15:08:04 -04:00
Russ Cox
1357f548b0 cmd/gc: fix two select temporary bugs
The introduction of temporaries in order.c was not
quite right for two corner cases:

1) The rewrite that pushed new variables on the lhs of
a receive into the body of the case was dropping the
declaration of the variables. If the variables escape,
the declaration is what allocates them.
Caught by escape analysis sanity check.
In fact the declarations should move into the body
always, so that we only allocate if the corresponding
case is selected. Do that. (This is an optimization that
was already present in Go 1.2. The new order code just
made it stop working.)

Fixes #7997.

2) The optimization to turn a single-recv select into
an ordinary receive assumed it could take the address
of the destination; not so if the destination is _.

Fixes #7998.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/100480043
2014-05-15 19:16:18 -04:00
Russ Cox
68aaf2ccda runtime: make scan of pointer-in-interface same as scan of pointer
The GC program describing a data structure sometimes trusts the
pointer base type and other times does not (if not, the garbage collector
must fall back on per-allocation type information stored in the heap).
Make the scanning of a pointer in an interface do the same.
This fixes a crash in a particular use of reflect.SliceHeader.

Fixes #8004.

LGTM=khr
R=golang-codereviews, khr
CC=0xe2.0x9a.0x9b, golang-codereviews, iant, r
https://golang.org/cl/100470045
2014-05-15 15:53:36 -04:00
Russ Cox
f5184d3437 cmd/gc: correct handling of globals, func args, results
Globals, function arguments, and results are special cases in
registerization.

Globals must be flushed aggressively, because nearly any
operation can cause a panic, and the recovery code must see
the latest values. Globals also must be loaded aggressively,
because nearly any store through a pointer might be updating a
global: the compiler cannot see all the "address of"
operations on globals, especially exported globals. To
accomplish this, mark all globals as having their address
taken, which effectively disables registerization.

If a function contains a defer statement, the function results
must be flushed aggressively, because nearly any operation can
cause a panic, and the deferred code may call recover, causing
the original function to return the current values of its
function results. To accomplish this, mark all function
results as having their address taken if the function contains
any defer statements. This causes not just aggressive flushing
but also aggressive loading. The aggressive loading is
overkill but the best we can do in the current code.

Function arguments must be considered live at all safe points
in a function, because garbage collection always preserves
them: they must be up-to-date in order to be preserved
correctly. Accomplish this by marking them live at all call
sites. An earlier attempt at this marked function arguments as
having their address taken, which disabled registerization
completely, making programs slower. This CL's solution allows
registerization while preserving safety. The benchmark speedup
is caused by being able to registerize again (the earlier CL
lost the same amount).

benchmark                old ns/op     new ns/op     delta
BenchmarkEqualPort32     61.4          56.0          -8.79%

benchmark                old MB/s     new MB/s     speedup
BenchmarkEqualPort32     521.56       570.97       1.09x

Fixes #1304. (again)
Fixes #7944. (again)
Fixes #7984.
Fixes #7995.

LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews, iant, r
https://golang.org/cl/97500044
2014-05-15 15:34:53 -04:00
Russ Cox
ec38c6f5e3 cmd/gc: fix duplicate map key check
Do not compare nil and true.

Fixes #7996.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/91470043
2014-05-15 15:34:37 -04:00
Mikio Hara
147a21456e test: fix flakey test case for issue 4388
Seems like we need to drag the stack for <autogenerated>:1 on Plan 9.

See http://build.golang.org/log/283b996102b833dd81c58301d78aceaa4fe9838b.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/95390043
2014-05-15 06:39:15 +09:00
Russ Cox
26ad5d4ff0 cmd/gc: fix liveness vs regopt mismatch for input variables
The inputs to a function are marked live at all times in the
liveness bitmaps, so that the garbage collector will not free
the things they point at and reuse the pointers, so that the
pointers shown in stack traces are guaranteed not to have
been recycled.

Unfortunately, no one told the register optimizer that the
inputs need to be preserved at all call sites. If a function
is done with a particular input value, the optimizer will stop
preserving it across calls. For single-word values this just
means that the value recorded might be stale. For multi-word
values like slices, the value recorded could be only partially stale:
it can happen that, say, the cap was updated but not the len,
or that the len was updated but not the base pointer.
Either of these possibilities (and others) would make the
garbage collector misinterpret memory, leading to memory
corruption.

This came up in a real program, in which the garbage collector's
'slice len ≤ slice cap' check caught the inconsistency.

Fixes #7944.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews, khr
https://golang.org/cl/100370045
2014-05-12 17:19:02 -04:00
Josh Bleecher Snyder
03c0f3fea9 cmd/gc: alias more variables during register allocation
This is joint work with Daniel Morsing.

In order for the register allocator to alias two variables, they must have the same width, stack offset, and etype. Code generation was altering a variable's etype in a few places. This prevented the variable from being moved to a register, which in turn prevented peephole optimization. This failure to alias was very common, with almost 23,000 instances just running make.bash.

This phenomenon was not visible in the register allocation debug output because the variables that failed to alias had the same name. The debugging-only change to bits.c fixes this by printing the variable number with its name.

This CL fixes the source of all etype mismatches for 6g, all but one case for 8g, and depressingly few cases for 5g. (I believe that extending CL 6819083 to 5g is a prerequisite.) Fixing the remaining cases in 8g and 5g is work for the future.

The etype mismatch fixes are:

* [gc] Slicing changed the type of the base pointer into a uintptr in order to perform arithmetic on it. Instead, support addition directly on pointers.

* [*g] OSPTR was giving type uintptr to slice base pointers; undo that. This arose, for example, while compiling copy(dst, src).

* [8g] 64 bit float conversion was assigning int64 type during codegen, overwriting the existing uint64 type.

Note that some etype mismatches are appropriate, such as a struct with a single field or an array with a single element.

With these fixes, the number of registerizations that occur while running make.bash for 6g increases ~10%. Hello world binary size shrinks ~1.5%. Running all benchmarks in the standard library show performance improvements ranging from nominal to substantive (>10%); a full comparison using 6g on my laptop is available at https://gist.github.com/josharian/8f9b5beb46667c272064. The microbenchmarks must be taken with a grain of salt; see issue 7920. The few benchmarks that show real regressions are likely due to issue 7920. I manually examined the generated code for the top few regressions and none had any assembly output changes. The few benchmarks that show extraordinary improvements are likely also due to issue 7920.

Performance results from 8g appear similar to 6g.

5g shows no performance improvements. This is not surprising, given the discussion above.

Update #7316

LGTM=rsc
R=rsc, daniel.morsing, bradfitz
CC=dave, golang-codereviews
https://golang.org/cl/91850043
2014-05-12 17:10:36 -04:00
Russ Cox
9b976f5f03 cmd/gc: record line number for auto-generated wrappers as <autogenerated>:1
Before we used line 1 of the first source file.
This should be clearer.

Fixes #4388.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/92250044
2014-05-12 11:59:55 -04:00
Josh Bleecher Snyder
1848d71445 cmd/gc: don't give credit for NOPs during register allocation
The register allocator decides which variables should be placed into registers by charging for each load/store and crediting for each use, and then selecting an allocation with minimal cost. NOPs will be eliminated, however, so using a variable in a NOP should not generate credit.

Issue 7867 arises from attempted registerization of multi-word variables because they are used in NOPs. By not crediting for that use, they will no longer be considered for registerization.

This fix could theoretically lead to better register allocation, but NOPs are rare relative to other instructions.

Fixes #7867.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/94810044
2014-05-09 09:55:17 -07:00
Ian Lance Taylor
d3764dd435 test: add test that gccgo compiled incorrectly
LGTM=minux.ma
R=golang-codereviews, minux.ma
CC=golang-codereviews
https://golang.org/cl/94100045
2014-05-06 09:01:38 -04:00
Shenghou Ma
32dffef098 cmd/gc: fix segfault in isgoconst.
Variables declared with 'var' have no sym->def.

Fixes #7794.

LGTM=rsc
R=golang-codereviews, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/88360043
2014-04-16 23:12:06 -04:00
Jan Ziak
1d2b71ce83 cmd/gc: fewer errors for wrong argument count
Fixes #7675

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/85040044
2014-04-16 22:42:09 -04:00
Russ Cox
c48db9a473 undo CL 66510044 / 6c0339d94123
Broke other things - see issue 7522.

Fixes #7522.
Reopens issue 7363.

««« original CL description
cmd/gc: make embedded, unexported fields read-only.

Fixes #7363.

LGTM=gri
R=gri, rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/66510044
»»»

LGTM=r, mpvl
R=golang-codereviews, r
CC=golang-codereviews, iant, mpvl
https://golang.org/cl/85580046
2014-04-14 09:48:11 -04:00
Jan Ziak
a599b4890a cmd/gc: increase specificity of errors in function call context
Fixes #7129

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/86470044
2014-04-11 15:57:30 +02:00
Jan Ziak
f973d9460f cmd/gc: fix typo in ordermapassign
Fixes #7742

LGTM=dave, rsc
R=rsc, bradfitz, dave
CC=golang-codereviews
https://golang.org/cl/85580047
2014-04-11 15:28:37 +02:00
Jan Ziak
397f129daf cmd/gc: avoid confusing error message "ovf in mpaddxx"
Fixes #6889

LGTM=rsc
R=gri, rsc
CC=golang-codereviews
https://golang.org/cl/85080044
2014-04-09 08:36:27 +02:00
Jan Ziak
907736e2fe cmd/gc: ignore blank (_) labels in label declarations
Fixes #7538

LGTM=rsc
R=gri, rsc
CC=golang-codereviews
https://golang.org/cl/85040045
2014-04-09 08:34:17 +02:00
Keith Randall
375b7bb767 cmd/gc: compute size of keys & values before making map bucket
Fixes #7547

LGTM=iant
R=iant, khr
CC=golang-codereviews
https://golang.org/cl/84470046
2014-04-04 12:58:19 -07:00
Jan Ziak
3072df5c1d cmd/gc: check duplicate keys in maps with interface{} key type
Fixes #7214

LGTM=rsc
R=golang-codereviews, bradfitz, rsc
CC=golang-codereviews, minux.ma
https://golang.org/cl/82080044
2014-04-04 16:46:23 +02:00
Dave Cheney
9121e7e4df runtime: check that new slice cap doesn't overflow
Fixes #7550.

LGTM=iant
R=golang-codereviews, iant, josharian
CC=golang-codereviews
https://golang.org/cl/83520043
2014-04-03 13:44:44 +11:00
Shenghou Ma
15bc7ab957 cmd/gc: fix spurious "bad negated constant" for complex constants.
Fixes #7648.

LGTM=r, remyoudompheng
R=golang-codereviews, r, remyoudompheng, jscrockett01
CC=golang-codereviews
https://golang.org/cl/80560045
2014-04-01 02:55:38 -04:00
Jan Ziak
2ca99505f6 cmd/gc: suppress array index error caused by a previously reported error
Fixes #7153

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/82180043
2014-03-29 15:45:40 +01:00
Russ Cox
6722d45631 cmd/gc: liveness-related bug fixes
1. On entry to a function, only zero the ambiguously live stack variables.
Before, we were zeroing all stack variables containing pointers.
The zeroing is pretty inefficient right now (issue 7624), but there are also
too many stack variables detected as ambiguously live (issue 7345),
and that must be addressed before deciding how to improve the zeroing code.
(Changes in 5g/ggen.c, 6g/ggen.c, 8g/ggen.c, gc/pgen.c)

Fixes #7647.

2. Make the regopt word-based liveness analysis preserve the
whole-variable liveness property expected by the garbage collection
bitmap liveness analysis. That is, if the regopt liveness decides that
one word in a struct needs to be preserved, make sure it preserves
the entire struct. This is particularly important for multiword values
such as strings, slices, and interfaces, in which all the words need
to be present in order to understand the meaning.
(Changes in 5g/reg.c, 6g/reg.c, 8g/reg.c.)

Fixes #7591.

3. Make the regopt word-based liveness analysis treat a variable
as having its address taken - which makes it preserved across
all future calls - whenever n->addrtaken is set, for consistency
with the gc bitmap liveness analysis, even if there is no machine
instruction actually taking the address. In this case n->addrtaken
is incorrect (a nicer way to put it is overconservative), and ideally
there would be no such cases, but they can happen and the two
analyses need to agree.
(Changes in 5g/reg.c, 6g/reg.c, 8g/reg.c; test in bug484.go.)

Fixes crashes found by turning off "zero everything" in step 1.

4. Remove spurious VARDEF annotations. As the comment in
gc/pgen.c explains, the VARDEF must immediately precede
the initialization. It cannot be too early, and it cannot be too late.
In particular, if a function call sits between the VARDEF and the
actual machine instructions doing the initialization, the variable
will be treated as live during that function call even though it is
uninitialized, leading to problems.
(Changes in gc/gen.c; test in live.go.)

Fixes crashes found by turning off "zero everything" in step 1.

5. Do not treat loading the address of a wide value as a signal
that the value must be initialized. Instead depend on the existence
of a VARDEF or the first actual read/write of a word in the value.
If the load is in order to pass the address to a function that does
the actual initialization, treating the load as an implicit VARDEF
causes the same problems as described in step 4.
The alternative is to arrange to zero every such value before
passing it to the real initialization function, but this is a much
easier and more efficient change.
(Changes in gc/plive.c.)

Fixes crashes found by turning off "zero everything" in step 1.

6. Treat wide input parameters with their address taken as
initialized on entry to the function. Otherwise they look
"ambiguously live" and we will try to emit code to zero them.
(Changes in gc/plive.c.)

Fixes crashes found by turning off "zero everything" in step 1.

7. An array of length 0 has no pointers, even if the element type does.
Without this change, the zeroing code complains when asked to
clear a 0-length array.
(Changes in gc/reflect.c.)

LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/80160044
2014-03-27 14:05:57 -04:00
Jan Ziak
21b2e16842 cmd/gc: fix spurious 'use of untyped nil' error
Fixes #6402

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/81340044
2014-03-27 18:47:00 +01:00
Jan Ziak
833dae6d26 cmd/gc: fix spurious 'const initializer is not a constant' error
Fixes #6403

LGTM=rsc
R=iant, rsc
CC=golang-codereviews
https://golang.org/cl/72840044
2014-03-24 20:36:42 +01:00
Jan Ziak
a43673cf8a cmd/gc: round floats with a large negative exponent towards zero
Fixes #6902

LGTM=iant
R=iant, rsc
CC=golang-codereviews
https://golang.org/cl/78730049
2014-03-24 10:10:29 -07:00
Rémy Oudompheng
0285d2b96b cmd/6g, cmd/8g: skip CONVNOP nodes in bgen.
Revision 3ae4607a43ff introduced CONVNOP layers
to fix type checking issues arising from comparisons.
The added complexity made 8g run out of registers
when compiling an equality function in go.net/ipv6.

A similar issue occurred in test/sizeof.go on
amd64p32 with 6g.

Fixes #7405.

LGTM=khr
R=rsc, dave, iant, khr
CC=golang-codereviews
https://golang.org/cl/78100044
2014-03-20 22:22:37 +01:00
Chris Manghane
260aa0ac85 test: add extra test case for issue 7590
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/78040043
2014-03-20 11:46:45 -07:00
Rémy Oudompheng
b4e41b4680 test: enable bug385_32 test on amd64p32.
LGTM=dave
R=dave, rsc
CC=golang-codereviews
https://golang.org/cl/78110043
2014-03-20 07:28:24 +01:00
Jan Ziak
cb50277510 cmd/gc: check exponent overflow and underflow in mparith
A too large float constant is an error.
A too small float constant is rounded to zero.

Fixes #7419
Update #6902

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/76730046
2014-03-19 05:48:00 +01:00
Chris Manghane
8a511cccb5 cmd/gc: fix error check for self-referential array type.
LGTM=gri, iant
R=gri, iant
CC=golang-codereviews
https://golang.org/cl/75920044
2014-03-17 20:26:19 -07:00
Brad Fitzpatrick
088b9a3c3d undo CL 77050045 / 073d79675aae
Breaks all builds.

««« original CL description
cmd/gc: Add tests for self-referential array types.

LGTM=gri, iant
R=gri, iant
CC=golang-codereviews
https://golang.org/cl/77050045
»»»

TBR=cmang
R=cmang
CC=golang-codereviews
https://golang.org/cl/77210043
2014-03-17 20:00:44 -07:00
Chris Manghane
e45f5cd5f1 cmd/gc: Add tests for self-referential array types.
LGTM=gri, iant
R=gri, iant
CC=golang-codereviews
https://golang.org/cl/77050045
2014-03-17 18:30:02 -07:00
Jan Ziak
1483747f3c cmd/gc: fix spurious 'not enough arguments to return' error
Fixes #6405

LGTM=rsc
R=rsc, iant
CC=golang-codereviews
https://golang.org/cl/72920046
2014-03-14 16:42:42 +01:00
Rémy Oudompheng
fcc10bc0f1 cmd/gc: fix spurious type errors in walkselect.
The lowering to runtime calls introduces hidden pointers to the
arguments of select clauses. When implicit conversions were
involved it could end up with incompatible pointers. Since the
pointed-to types have the same representation, we can introduce a
forced conversion.

Fixes #6847.

LGTM=rsc
R=rsc, iant, khr
CC=golang-codereviews
https://golang.org/cl/72380043
2014-03-13 08:14:05 +01:00
Josh Bleecher Snyder
4e5f31a760 liblink: fix bad code generated for MOVFD/MOVDF when reg > 7
The byte that r is or'd into is already 0x7, so the failure to zero r only
impacts the generated machine code if the register is > 7.

Fixes #7044.

LGTM=dave, minux.ma, rsc
R=dave, minux.ma, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/73730043
2014-03-11 14:04:44 -04:00
Chris Manghane
671cc6efba cmd/gc: allow append and complex builtins to accept 2-result call expression as first argument.
Fixes #5793.

LGTM=rsc
R=rsc, adonovan, dave
CC=golang-codereviews
https://golang.org/cl/13367051
2014-03-05 14:16:21 -05:00
Rémy Oudompheng
52e6d7c622 cmd/gc: use a register to checknil constants.
Fixes #7346.

LGTM=rsc
R=rsc, iant, khr
CC=golang-codereviews
https://golang.org/cl/69050044
2014-03-04 08:18:17 +01:00
Russ Cox
56b983c112 cmd/gc: fix internal crash
TBR=ken2
CC=golang-codereviews
https://golang.org/cl/70200053
2014-03-03 19:55:40 -05:00
Rémy Oudompheng
14b0af4272 cmd/gc: fix walkcompare bugs.
Revision c0e0467635ec (cmd/gc: return canonical Node* from temp)
exposed original nodes of temporaries, allowing callers to mutate
their types.

In walkcompare a temporary could be typed as ideal because of
this. Additionnally, assignment of a comparison result to
a custom boolean type was broken.

Fixes #7366.

LGTM=rsc
R=rsc, iant, khr
CC=golang-codereviews
https://golang.org/cl/66930044
2014-02-24 19:51:59 +01:00
Shenghou Ma
e33e47e844 cmd/gc: diagnose "make([]T, non-integer)" correctly.
Fixes #7223.

LGTM=rsc
R=golang-codereviews, gobot, rsc
CC=golang-codereviews
https://golang.org/cl/63040043
2014-02-23 16:31:48 -05:00