6303331c33
The gc compiler recognizes append(s, make([]T, n)...), and
generates code to directly zero the tail instead of allocating a
new slice and copying. This CL lets the Go frontend do basically
the same.
The difficulty is that at the point we handle append, there may
already be temporaries introduced (e.g. in order_evaluations),
which makes it hard to find the append-of-make pattern. The
compiler could "see through" the value of a temporary, but it is
only safe to do if the temporary is not assigned multiple times.
For this, we add tracking of assignments and uses for temporaries.
This also helps in optimizing non-escape slice make. We already
optimize non-escape slice make with constant len/cap to stack
allocation. But it failed to handle things like f(make([]T, n))
(where the slice doesn't escape and n is constant), because of
the temporary. With tracking of temporary assignments and uses,
it can handle this now as well.
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/179597
From-SVN: r271822
119 lines
3.4 KiB
C
119 lines
3.4 KiB
C
/* go-runtime-error.c -- Go runtime error.
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Copyright 2010 The Go Authors. All rights reserved.
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file. */
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#include "runtime.h"
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/* The compiler generates calls to this function. This enum values
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are known to the compiler and used by compiled code. Any change
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here must be reflected in the compiler. */
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enum
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{
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/* Slice index out of bounds: negative or larger than the length of
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the slice. */
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SLICE_INDEX_OUT_OF_BOUNDS = 0,
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/* Array index out of bounds. */
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ARRAY_INDEX_OUT_OF_BOUNDS = 1,
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/* String index out of bounds. */
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STRING_INDEX_OUT_OF_BOUNDS = 2,
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/* Slice slice out of bounds: negative or larger than the length of
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the slice or high bound less than low bound. */
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SLICE_SLICE_OUT_OF_BOUNDS = 3,
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/* Array slice out of bounds. */
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ARRAY_SLICE_OUT_OF_BOUNDS = 4,
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/* String slice out of bounds. */
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STRING_SLICE_OUT_OF_BOUNDS = 5,
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/* Dereference of nil pointer. This is used when there is a
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dereference of a pointer to a very large struct or array, to
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ensure that a gigantic array is not used a proxy to access random
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memory locations. */
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NIL_DEREFERENCE = 6,
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/* Slice length out of bounds in make: negative or overflow or length
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greater than capacity. */
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MAKE_SLICE_LEN_OUT_OF_BOUNDS = 7,
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/* Slice capacity out of bounds in make: negative. */
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MAKE_SLICE_CAP_OUT_OF_BOUNDS = 8,
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/* Map capacity out of bounds in make: negative or overflow. */
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MAKE_MAP_OUT_OF_BOUNDS = 9,
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/* Channel capacity out of bounds in make: negative or overflow. */
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MAKE_CHAN_OUT_OF_BOUNDS = 10,
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/* Integer division by zero. */
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DIVISION_BY_ZERO = 11,
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/* Go statement with nil function. */
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GO_NIL = 12
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};
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extern void __go_runtime_error (int32) __attribute__ ((noreturn));
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void
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__go_runtime_error (int32 i)
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{
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struct funcfileline_return fileline;
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bool in_runtime;
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fileline = runtime_funcfileline ((uintptr) runtime_getcallerpc()-1, 0);
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in_runtime = (fileline.retfn.len > 0
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&& (__builtin_strncmp ((const char *) fileline.retfn.str,
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"runtime.", 8)
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== 0));
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switch (i)
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{
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case SLICE_INDEX_OUT_OF_BOUNDS:
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case ARRAY_INDEX_OUT_OF_BOUNDS:
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case STRING_INDEX_OUT_OF_BOUNDS:
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if (in_runtime)
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runtime_throw ("index out of range");
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runtime_panicstring ("index out of range");
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case SLICE_SLICE_OUT_OF_BOUNDS:
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case ARRAY_SLICE_OUT_OF_BOUNDS:
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case STRING_SLICE_OUT_OF_BOUNDS:
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if (in_runtime)
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runtime_throw ("slice bounds out of range");
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runtime_panicstring ("slice bounds out of range");
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case NIL_DEREFERENCE:
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runtime_panicstring ("nil pointer dereference");
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case MAKE_SLICE_LEN_OUT_OF_BOUNDS:
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runtime_panicstring ("make slice len out of range");
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case MAKE_SLICE_CAP_OUT_OF_BOUNDS:
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runtime_panicstring ("make slice cap out of range");
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case MAKE_MAP_OUT_OF_BOUNDS:
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runtime_panicstring ("make map len out of range");
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case MAKE_CHAN_OUT_OF_BOUNDS:
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runtime_panicstring ("make chan len out of range");
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case DIVISION_BY_ZERO:
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runtime_panicstring ("integer divide by zero");
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case GO_NIL:
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/* This one is a throw, rather than a panic. Set throwing to
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not dump full stacks. */
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runtime_g()->m->throwing = -1;
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runtime_throw ("go of nil func value");
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default:
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runtime_panicstring ("unknown runtime error");
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}
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}
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