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// Copyright 2018 the V8 project 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 "src/instruction-stream.h"
#include "src/builtins/builtins.h"
#include "src/heap/heap.h"
#include "src/objects-inl.h"
#include "src/objects/code-inl.h"
namespace v8 {
namespace internal {
InstructionStream::InstructionStream(Code* code)
: builtin_index_(code->builtin_index()) {
DCHECK(Builtins::IsOffHeapBuiltin(code));
const size_t page_size = AllocatePageSize();
byte_length_ =
RoundUp(static_cast<size_t>(code->instruction_size()), page_size);
bytes_ = static_cast<uint8_t*>(AllocatePages(
GetRandomMmapAddr(), byte_length_, page_size, PageAllocator::kReadWrite));
CHECK_NOT_NULL(bytes_);
std::memcpy(bytes_, code->instruction_start(), code->instruction_size());
CHECK(SetPermissions(bytes_, byte_length_, PageAllocator::kReadExecute));
}
InstructionStream::~InstructionStream() {
CHECK(FreePages(bytes_, byte_length_));
}
// static
Code* InstructionStream::TryLookupCode(Isolate* isolate, Address address) {
DCHECK(FLAG_stress_off_heap_code);
// TODO(jgruber,v8:6666): Replace with binary search through range checks
// once off-heap code is mapped into a contiguous memory space.
for (const InstructionStream* stream : isolate->off_heap_code_) {
if (stream->Contains(address)) {
return isolate->builtins()->builtin(stream->builtin_index());
}
}
return nullptr;
}
// static
InstructionStream* InstructionStream::TryLookupInstructionStream(
Isolate* isolate, Code* code) {
DCHECK(FLAG_stress_off_heap_code);
// TODO(jgruber,v8:6666): Replace with binary search through range checks
// once off-heap code is mapped into a contiguous memory space.
const int builtin_index = code->builtin_index();
DCHECK(Builtins::IsBuiltinId(builtin_index));
for (InstructionStream* stream : isolate->off_heap_code_) {
if (stream->builtin_index() == builtin_index) return stream;
}
return nullptr;
}
bool InstructionStream::Contains(Address address) const {
return bytes_ <= address && address < bytes_ + byte_length_;
}
} // namespace internal
} // namespace v8
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