зеркало из https://github.com/mozilla/gecko-dev.git
123 строки
4.2 KiB
C++
123 строки
4.2 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/*
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* Structures and functions for transcoding compiled scripts and functions to
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* and from memory.
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*/
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#ifndef js_Transcoding_h
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#define js_Transcoding_h
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#include "mozilla/Range.h" // mozilla::Range
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#include "mozilla/Vector.h" // mozilla::Vector
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#include <stddef.h> // size_t
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#include <stdint.h> // uint8_t, uint32_t
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#include "js/TypeDecls.h"
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namespace JS {
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class ReadOnlyCompileOptions;
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using TranscodeBuffer = mozilla::Vector<uint8_t>;
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using TranscodeRange = mozilla::Range<const uint8_t>;
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struct TranscodeSource final {
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TranscodeSource(const TranscodeRange& range_, const char* file, uint32_t line)
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: range(range_), filename(file), lineno(line) {}
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const TranscodeRange range;
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const char* filename;
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const uint32_t lineno;
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};
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using TranscodeSources = mozilla::Vector<TranscodeSource>;
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enum class TranscodeResult : uint8_t {
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// Successful encoding / decoding.
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Ok = 0,
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// A warning message, is set to the message out-param.
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Failure = 0x10,
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Failure_BadBuildId = Failure | 0x1,
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Failure_AsmJSNotSupported = Failure | 0x2,
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Failure_BadDecode = Failure | 0x3,
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// There is a pending exception on the context.
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Throw = 0x20
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};
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inline bool IsTranscodeFailureResult(const TranscodeResult result) {
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uint8_t raw_result = static_cast<uint8_t>(result);
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uint8_t raw_failure = static_cast<uint8_t>(TranscodeResult::Failure);
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TranscodeResult masked =
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static_cast<TranscodeResult>(raw_result & raw_failure);
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return masked == TranscodeResult::Failure;
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}
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static constexpr size_t BytecodeOffsetAlignment = 4;
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static_assert(BytecodeOffsetAlignment <= alignof(std::max_align_t),
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"Alignment condition requires a custom allocator.");
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// Align the bytecode offset for transcoding for the requirement.
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inline size_t AlignTranscodingBytecodeOffset(size_t offset) {
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size_t extra = offset % BytecodeOffsetAlignment;
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if (extra == 0) {
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return offset;
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}
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size_t padding = BytecodeOffsetAlignment - extra;
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return offset + padding;
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}
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inline bool IsTranscodingBytecodeOffsetAligned(size_t offset) {
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return offset % BytecodeOffsetAlignment == 0;
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}
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inline bool IsTranscodingBytecodeAligned(const void* offset) {
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return IsTranscodingBytecodeOffsetAligned(size_t(offset));
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}
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// Finish incremental encoding started by one of:
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// * JS::CompileAndStartIncrementalEncoding
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// * JS::FinishOffThreadScriptAndStartIncrementalEncoding
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//
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// The |script| argument of |FinishIncrementalEncoding| should be the top-level
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// script returned from one of the above.
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//
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// The |buffer| argument of |FinishIncrementalEncoding| is used for appending
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// the encoded bytecode into the buffer. If any of these functions failed, the
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// content of |buffer| would be undefined.
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//
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// |buffer| contains encoded CompilationStencil.
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//
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// If the `buffer` isn't empty, the start of the `buffer` should meet
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// IsTranscodingBytecodeAligned, and the length should meet
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// IsTranscodingBytecodeOffsetAligned.
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//
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// NOTE: As long as IsTranscodingBytecodeOffsetAligned is met, that means
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// there's JS::BytecodeOffsetAlignment+extra bytes in the buffer,
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// IsTranscodingBytecodeAligned should be guaranteed to meet by
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// malloc, used by MallocAllocPolicy in mozilla::Vector.
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extern JS_PUBLIC_API bool FinishIncrementalEncoding(JSContext* cx,
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Handle<JSScript*> script,
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TranscodeBuffer& buffer);
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// Check if the compile options and script's flag matches.
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//
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// JS::DecodeScript* and JS::DecodeOffThreadScript internally check this.
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//
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// JS::DecodeMultiStencilsOffThread checks some options shared across multiple
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// scripts. Caller is responsible for checking each script with this API when
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// using the decoded script instead of compiling a new script wiht the given
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// options.
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extern JS_PUBLIC_API bool CheckCompileOptionsMatch(
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const ReadOnlyCompileOptions& options, JSScript* script);
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} // namespace JS
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#endif /* js_Transcoding_h */
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