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// Copyright 2017, VIXL authors
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of ARM Limited nor the names of its contributors may be
// used to endorse or promote products derived from this software without
// specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
extern "C" {
#include <sys/mman.h>
}
#include "code-buffer-vixl.h"
#include "utils-vixl.h"
namespace vixl {
// BSD uses `MAP_ANON` instead of the Linux `MAP_ANONYMOUS`. The `MAP_ANONYMOUS`
// alias should generally be available, but is not always, so define it manually
// if necessary.
#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
#define MAP_ANONYMOUS MAP_ANON
#endif
CodeBuffer::CodeBuffer(size_t capacity)
: buffer_(NULL),
managed_(true),
cursor_(NULL),
dirty_(false),
capacity_(capacity) {
if (capacity_ == 0) {
return;
}
#ifdef VIXL_CODE_BUFFER_MALLOC
buffer_ = reinterpret_cast<byte*>(malloc(capacity_));
#elif defined(VIXL_CODE_BUFFER_MMAP)
buffer_ = reinterpret_cast<byte*>(mmap(NULL,
capacity,
PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS,
-1,
0));
#else
#error Unknown code buffer allocator.
#endif
VIXL_CHECK(buffer_ != NULL);
// Aarch64 instructions must be word aligned, we assert the default allocator
// always returns word align memory.
VIXL_ASSERT(IsWordAligned(buffer_));
cursor_ = buffer_;
}
CodeBuffer::CodeBuffer(byte* buffer, size_t capacity)
: buffer_(reinterpret_cast<byte*>(buffer)),
managed_(false),
cursor_(reinterpret_cast<byte*>(buffer)),
dirty_(false),
capacity_(capacity) {
VIXL_ASSERT(buffer_ != NULL);
}
CodeBuffer::~CodeBuffer() {
VIXL_ASSERT(!IsDirty());
if (managed_) {
#ifdef VIXL_CODE_BUFFER_MALLOC
free(buffer_);
#elif defined(VIXL_CODE_BUFFER_MMAP)
munmap(buffer_, capacity_);
#else
#error Unknown code buffer allocator.
#endif
}
}
#ifdef VIXL_CODE_BUFFER_MMAP
void CodeBuffer::SetExecutable() {
int ret = mprotect(buffer_, capacity_, PROT_READ | PROT_EXEC);
VIXL_CHECK(ret == 0);
}
#endif
#ifdef VIXL_CODE_BUFFER_MMAP
void CodeBuffer::SetWritable() {
int ret = mprotect(buffer_, capacity_, PROT_READ | PROT_WRITE);
VIXL_CHECK(ret == 0);
}
#endif
void CodeBuffer::EmitString(const char* string) {
VIXL_ASSERT(HasSpaceFor(strlen(string) + 1));
char* dst = reinterpret_cast<char*>(cursor_);
dirty_ = true;
char* null_char = stpcpy(dst, string);
cursor_ = reinterpret_cast<byte*>(null_char) + 1;
}
void CodeBuffer::EmitData(const void* data, size_t size) {
VIXL_ASSERT(HasSpaceFor(size));
dirty_ = true;
memcpy(cursor_, data, size);
cursor_ = cursor_ + size;
}
void CodeBuffer::UpdateData(size_t offset, const void* data, size_t size) {
dirty_ = true;
byte* dst = buffer_ + offset;
VIXL_ASSERT(dst + size <= cursor_);
memcpy(dst, data, size);
}
void CodeBuffer::Align() {
byte* end = AlignUp(cursor_, 4);
const size_t padding_size = end - cursor_;
VIXL_ASSERT(padding_size <= 4);
EmitZeroedBytes(static_cast<int>(padding_size));
}
void CodeBuffer::EmitZeroedBytes(int n) {
EnsureSpaceFor(n);
dirty_ = true;
memset(cursor_, 0, n);
cursor_ += n;
}
void CodeBuffer::Reset() {
#ifdef VIXL_DEBUG
if (managed_) {
// Fill with zeros (there is no useful value common to A32 and T32).
memset(buffer_, 0, capacity_);
}
#endif
cursor_ = buffer_;
SetClean();
}
void CodeBuffer::Grow(size_t new_capacity) {
VIXL_ASSERT(managed_);
VIXL_ASSERT(new_capacity > capacity_);
ptrdiff_t cursor_offset = GetCursorOffset();
#ifdef VIXL_CODE_BUFFER_MALLOC
buffer_ = static_cast<byte*>(realloc(buffer_, new_capacity));
VIXL_CHECK(buffer_ != NULL);
#elif defined(VIXL_CODE_BUFFER_MMAP)
#ifdef __APPLE__
// TODO: Avoid using VIXL_CODE_BUFFER_MMAP.
// Don't use false to avoid having the compiler realize it's a noreturn
// method.
VIXL_ASSERT(!managed_);
#else
buffer_ = static_cast<byte*>(
mremap(buffer_, capacity_, new_capacity, MREMAP_MAYMOVE));
VIXL_CHECK(buffer_ != MAP_FAILED);
#endif
#else
#error Unknown code buffer allocator.
#endif
cursor_ = buffer_ + cursor_offset;
capacity_ = new_capacity;
}
} // namespace vixl