gcc/libgo/runtime/go-memequal.c

/* go-memequal.c -- compare memory buffers for equality

   Copyright 2016 The Go Authors. All rights reserved.
   Use of this source code is governed by a BSD-style
   license that can be found in the LICENSE file.  */

#include "runtime.h"

_Bool memequal (void *, void *, uintptr)
  __asm__ (GOSYM_PREFIX "runtime.memequal");

_Bool
memequal (void *p1, void *p2, uintptr len)
{
  return __builtin_memcmp (p1, p2, len) == 0;
}
compiler, runtime: replace hashmap code with Go 1.7 hashmap This change removes the gccgo-specific hashmap code and replaces it with the hashmap code from the Go 1.7 runtime. The Go 1.7 hashmap code is more efficient, does a better job on details like when to update a key, and provides some support against denial-of-service attacks. The compiler is changed to call the new hashmap functions instead of the old ones. The compiler now tracks which types are reflexive and which require updating when used as a map key, and records the information in map type descriptors. Map_index_expression is simplified. The special case for a map index on the right hand side of a tuple expression has been unnecessary for some time, and is removed. The support for specially marking a map index as an lvalue is removed, in favor of lowering an assignment to a map index into a function call. The long-obsolete support for a map index of a pointer to a map is removed. The __go_new_map_big function (known to the compiler as Runtime::MAKEMAPBIG) is no longer needed, as the new runtime.makemap function takes an int64 hint argument. The old map descriptor type and supporting expression is removed. The compiler was still supporting the long-obsolete syntax `m[k] = 0, false` to delete a value from a map. That is now removed, requiring a change to one of the gccgo-specific tests. The builtin len function applied to a map or channel p is now compiled as `p == nil ? 0 : (int)(p)`. The __go_chan_len function (known to the compiler as Runtime::CHAN_LEN) is removed. Support for a shared zero value for maps to large value types is introduced, along the lines of the gc compiler. The zero value is handled as a common variable. The hash function is changed to take a seed argument, changing the runtime hash functions and the compiler-generated hash functions. Unlike the gc compiler, both the hash and equal functions continue to take the type length. Types that can not be compared now store nil for the hash and equal functions, rather than pointing to functions that throw. Interface hash and comparison functions now check explicitly for nil. This matches the gc compiler and permits a simple implementation for ismapkey. The compiler is changed to permit marking struct and array types as incomparable, meaning that they have no hash or equal function. We use this for thunk types, removing the existing special code to avoid generating hash/equal functions for them. The C runtime code adds memclr, memequal, and memmove functions. The hashmap code uses go:linkname comments to make the functions visible, as otherwise the compiler would discard them. The hashmap code comments out the unused reference to the address of the first parameter in the race code, as otherwise the compiler thinks that the parameter escapes and copies it onto the heap. This is probably not needed when we enable escape analysis. Several runtime map tests that ere previously skipped for gccgo are now run. The Go runtime picks up type kind information and stubs. The type kind information causes the generated runtime header file to define some constants, including `empty`, and the C code is adjusted accordingly. A Go-callable version of runtime.throw, that takes a Go string, is added to be called from the hashmap code. Reviewed-on: https://go-review.googlesource.com/29447 * go.go-torture/execute/map-1.go: Replace old map deletion syntax with call to builtin delete function. From-SVN: r240334 2016-09-21 22:58:51 +02:00			`/* go-memequal.c -- compare memory buffers for equality`

			`Copyright 2016 The Go Authors. All rights reserved.`
			`Use of this source code is governed by a BSD-style`
			`license that can be found in the LICENSE file. */`

			`#include "runtime.h"`

			`_Bool memequal (void , void , uintptr)`
			`__asm__ (GOSYM_PREFIX "runtime.memequal");`

			`_Bool`
			`memequal (void p1, void p2, uintptr len)`
			`{`
			`return __builtin_memcmp (p1, p2, len) == 0;`
			`}`