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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* Structures and functions for transcoding compiled scripts and functions to
* and from memory.
*/
#ifndef js_Transcoding_h
#define js_Transcoding_h
#include "mozilla/Range.h" // mozilla::Range
#include "mozilla/Vector.h" // mozilla::Vector
#include <stddef.h> // size_t
#include <stdint.h> // uint8_t, uint32_t
#include "js/TypeDecls.h"
// Underlying opaque type.
namespace js::frontend {
struct InitialStencilAndDelazifications;
} // namespace js::frontend
namespace JS {
using Stencil = js::frontend::InitialStencilAndDelazifications;
class JS_PUBLIC_API ReadOnlyCompileOptions;
using TranscodeBuffer = mozilla::Vector<uint8_t>;
using TranscodeRange = mozilla::Range<const uint8_t>;
struct TranscodeSource final {
TranscodeSource(const TranscodeRange& range_, const char* file, uint32_t line)
: range(range_), filename(file), lineno(line) {}
const TranscodeRange range;
const char* filename;
const uint32_t lineno;
};
enum class TranscodeResult : uint8_t {
// Successful encoding / decoding.
Ok = 0,
// A warning message, is set to the message out-param.
Failure = 0x10,
Failure_BadBuildId = Failure | 0x1,
Failure_AsmJSNotSupported = Failure | 0x2,
Failure_BadDecode = Failure | 0x3,
// There is a pending exception on the context.
Throw = 0x20
};
inline bool IsTranscodeFailureResult(const TranscodeResult result) {
uint8_t raw_result = static_cast<uint8_t>(result);
uint8_t raw_failure = static_cast<uint8_t>(TranscodeResult::Failure);
TranscodeResult masked =
static_cast<TranscodeResult>(raw_result & raw_failure);
return masked == TranscodeResult::Failure;
}
static constexpr size_t BytecodeOffsetAlignment = 4;
static_assert(BytecodeOffsetAlignment <= alignof(std::max_align_t),
"Alignment condition requires a custom allocator.");
// Align the bytecode offset for transcoding for the requirement.
inline size_t AlignTranscodingBytecodeOffset(size_t offset) {
size_t extra = offset % BytecodeOffsetAlignment;
if (extra == 0) {
return offset;
}
size_t padding = BytecodeOffsetAlignment - extra;
return offset + padding;
}
inline bool IsTranscodingBytecodeOffsetAligned(size_t offset) {
return offset % BytecodeOffsetAlignment == 0;
}
inline bool IsTranscodingBytecodeAligned(const void* offset) {
return IsTranscodingBytecodeOffsetAligned(size_t(offset));
}
// Check if the compile options and script's flag matches.
//
// JS::DecodeScript* and JS::DecodeOffThreadScript internally check this.
extern JS_PUBLIC_API bool CheckCompileOptionsMatch(
const ReadOnlyCompileOptions& options, JSScript* script);
} // namespace JS
#endif /* js_Transcoding_h */
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