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Diffstat (limited to 'js/src/frontend/StencilXdr.h')
| -rw-r--r-- | js/src/frontend/StencilXdr.h | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/js/src/frontend/StencilXdr.h b/js/src/frontend/StencilXdr.h new file mode 100644 index 0000000000..cf77ea12cc --- /dev/null +++ b/js/src/frontend/StencilXdr.h @@ -0,0 +1,217 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sts=2 et sw=2 tw=80: + * 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/. */ + +#ifndef frontend_StencilXdr_h +#define frontend_StencilXdr_h + +#include "mozilla/RefPtr.h" // RefPtr + +#include "frontend/ParserAtom.h" // ParserAtom, ParserAtomSpan +#include "frontend/Stencil.h" // BitIntStencil, ScopeStencil, BaseParserScopeData +#include "vm/Xdr.h" // XDRMode, XDRResult, XDRState + +namespace JS { + +class ReadOnlyDecodeOptions; + +} // namespace JS + +namespace js { + +class LifoAlloc; +class ObjLiteralStencil; +class ScriptSource; +class SharedImmutableScriptData; + +class XDRStencilDecoder; +class XDRStencilEncoder; + +namespace frontend { + +struct CompilationStencil; +struct ExtensibleCompilationStencil; +struct SharedDataContainer; + +// Check that we can copy data to disk and restore it in another instance of +// the program in a different address space. +template <typename DataT> +struct CanCopyDataToDisk { + // Check that the object is fully packed, to save disk space. +#ifdef __cpp_lib_has_unique_object_representations + static constexpr bool unique_repr = + std::has_unique_object_representations<DataT>(); +#else + static constexpr bool unique_repr = true; +#endif + + // Approximation which assumes that 32bits variant of the class would not + // have pointers if the 64bits variant does not have pointer. + static constexpr bool no_pointer = + alignof(DataT) < alignof(void*) || sizeof(void*) == sizeof(uint32_t); + + static constexpr bool value = unique_repr && no_pointer; +}; + +// This is just a namespace class that can be used in friend declarations, +// so that the statically declared XDR methods within have access to the +// relevant struct internals. +class StencilXDR { + private: + template <XDRMode mode> + [[nodiscard]] static XDRResult codeSourceUnretrievableUncompressed( + XDRState<mode>* xdr, ScriptSource* ss, uint8_t sourceCharSize, + uint32_t uncompressedLength); + + template <typename Unit, + template <typename U, SourceRetrievable CanRetrieve> class Data, + XDRMode mode> + static void codeSourceRetrievable(ScriptSource* ss); + + template <typename Unit, XDRMode mode> + [[nodiscard]] static XDRResult codeSourceUncompressedData( + XDRState<mode>* const xdr, ScriptSource* const ss); + + template <typename Unit, XDRMode mode> + [[nodiscard]] static XDRResult codeSourceCompressedData( + XDRState<mode>* const xdr, ScriptSource* const ss); + + template <typename Unit, XDRMode mode> + static void codeSourceRetrievableData(ScriptSource* ss); + + template <XDRMode mode> + [[nodiscard]] static XDRResult codeSourceData(XDRState<mode>* const xdr, + ScriptSource* const ss); + + public: + template <XDRMode mode> + static XDRResult codeSource(XDRState<mode>* xdr, + const JS::ReadOnlyDecodeOptions* maybeOptions, + RefPtr<ScriptSource>& source); + + template <XDRMode mode> + static XDRResult codeBigInt(XDRState<mode>* xdr, LifoAlloc& alloc, + BigIntStencil& stencil); + + template <XDRMode mode> + static XDRResult codeObjLiteral(XDRState<mode>* xdr, LifoAlloc& alloc, + ObjLiteralStencil& stencil); + + template <XDRMode mode> + static XDRResult codeScopeData(XDRState<mode>* xdr, LifoAlloc& alloc, + ScopeStencil& stencil, + BaseParserScopeData*& baseScopeData); + + template <XDRMode mode> + static XDRResult codeSharedData(XDRState<mode>* xdr, + RefPtr<SharedImmutableScriptData>& sisd); + + template <XDRMode mode> + static XDRResult codeSharedDataContainer(XDRState<mode>* xdr, + SharedDataContainer& sharedData); + + template <XDRMode mode> + static XDRResult codeParserAtom(XDRState<mode>* xdr, LifoAlloc& alloc, + ParserAtom** atomp); + + template <XDRMode mode> + static XDRResult codeParserAtomSpan(XDRState<mode>* xdr, LifoAlloc& alloc, + ParserAtomSpan& parserAtomData); + + template <XDRMode mode> + static XDRResult codeModuleRequest(XDRState<mode>* xdr, + StencilModuleRequest& stencil); + + template <XDRMode mode> + static XDRResult codeModuleRequestVector( + XDRState<mode>* xdr, StencilModuleMetadata::RequestVector& vector); + + template <XDRMode mode> + static XDRResult codeModuleEntry(XDRState<mode>* xdr, + StencilModuleEntry& stencil); + + template <XDRMode mode> + static XDRResult codeModuleEntryVector( + XDRState<mode>* xdr, StencilModuleMetadata::EntryVector& vector); + + template <XDRMode mode> + static XDRResult codeModuleMetadata(XDRState<mode>* xdr, + StencilModuleMetadata& stencil); + + static XDRResult checkCompilationStencil(XDRStencilEncoder* encoder, + const CompilationStencil& stencil); + + static XDRResult checkCompilationStencil( + const ExtensibleCompilationStencil& stencil); + + template <XDRMode mode> + static XDRResult codeCompilationStencil(XDRState<mode>* xdr, + CompilationStencil& stencil); +}; + +} /* namespace frontend */ + +/* + * The structure of the Stencil XDR buffer is: + * + * 1. Version + * 2. length of content + * 3. checksum of content + * 4. content + * a. ScriptSource + * b. CompilationStencil + */ + +/* + * The stencil decoder accepts `range` as input. + * + * The decoded stencils are outputted to the default-initialized + * `stencil` parameter of `codeStencil` method. + * + * The decoded stencils borrow the input `buffer`/`range`, and the consumer + * has to keep the buffer alive while the decoded stencils are alive. + */ +class XDRStencilDecoder : public XDRState<XDR_DECODE> { + using Base = XDRState<XDR_DECODE>; + + public: + XDRStencilDecoder(FrontendContext* fc, const JS::TranscodeRange& range) + : Base(fc, range) { + MOZ_ASSERT(JS::IsTranscodingBytecodeAligned(range.begin().get())); + } + + XDRResult codeStencil(const JS::ReadOnlyDecodeOptions& options, + frontend::CompilationStencil& stencil); + + const JS::ReadOnlyDecodeOptions& options() { + MOZ_ASSERT(options_); + return *options_; + } + + private: + const JS::ReadOnlyDecodeOptions* options_ = nullptr; +}; + +class XDRStencilEncoder : public XDRState<XDR_ENCODE> { + using Base = XDRState<XDR_ENCODE>; + + public: + XDRStencilEncoder(FrontendContext* fc, JS::TranscodeBuffer& buffer) + : Base(fc, buffer, buffer.length()) { + // NOTE: If buffer is empty, buffer.begin() doesn't point valid buffer. + MOZ_ASSERT_IF(!buffer.empty(), + JS::IsTranscodingBytecodeAligned(buffer.begin())); + MOZ_ASSERT(JS::IsTranscodingBytecodeOffsetAligned(buffer.length())); + } + + XDRResult codeStencil(const RefPtr<ScriptSource>& source, + const frontend::CompilationStencil& stencil); + + XDRResult codeStencil(const frontend::CompilationStencil& stencil); +}; + +} /* namespace js */ + +#endif /* frontend_StencilXdr_h */ |