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