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Diffstat (limited to 'include/clang/Frontend/PCHReader.h')
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1 files changed, 567 insertions, 0 deletions
diff --git a/include/clang/Frontend/PCHReader.h b/include/clang/Frontend/PCHReader.h new file mode 100644 index 0000000..1e00ae3 --- /dev/null +++ b/include/clang/Frontend/PCHReader.h @@ -0,0 +1,567 @@ +//===--- PCHReader.h - Precompiled Headers Reader ---------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file defines the PCHReader class, which reads a precompiled header. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_FRONTEND_PCH_READER_H +#define LLVM_CLANG_FRONTEND_PCH_READER_H + +#include "clang/Frontend/PCHBitCodes.h" +#include "clang/AST/DeclarationName.h" +#include "clang/Sema/ExternalSemaSource.h" +#include "clang/AST/DeclObjC.h" +#include "clang/AST/Type.h" +#include "clang/Basic/Diagnostic.h" +#include "clang/Basic/IdentifierTable.h" +#include "clang/Basic/SourceManager.h" +#include "llvm/ADT/APFloat.h" +#include "llvm/ADT/APInt.h" +#include "llvm/ADT/APSInt.h" +#include "llvm/ADT/DenseMap.h" +#include "llvm/ADT/OwningPtr.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/Bitcode/BitstreamReader.h" +#include "llvm/Support/DataTypes.h" +#include <map> +#include <string> +#include <utility> +#include <vector> + +namespace llvm { + class MemoryBuffer; +} + +namespace clang { + +class AddrLabelExpr; +class ASTConsumer; +class ASTContext; +class Attr; +class Decl; +class DeclContext; +class GotoStmt; +class LabelStmt; +class NamedDecl; +class Preprocessor; +class Sema; +class SwitchCase; + +/// \brief Reads a precompiled head containing the contents of a +/// translation unit. +/// +/// The PCHReader class reads a bitstream (produced by the PCHWriter +/// class) containing the serialized representation of a given +/// abstract syntax tree and its supporting data structures. An +/// instance of the PCHReader can be attached to an ASTContext object, +/// which will provide access to the contents of the PCH file. +/// +/// The PCH reader provides lazy de-serialization of declarations, as +/// required when traversing the AST. Only those AST nodes that are +/// actually required will be de-serialized. +class PCHReader + : public ExternalSemaSource, + public IdentifierInfoLookup, + public ExternalIdentifierLookup, + public ExternalSLocEntrySource { +public: + enum PCHReadResult { Success, Failure, IgnorePCH }; + +private: + /// \brief The semantic analysis object that will be processing the + /// PCH file and the translation unit that uses it. + Sema *SemaObj; + + /// \brief The preprocessor that will be loading the source file. + Preprocessor &PP; + + /// \brief The AST context into which we'll read the PCH file. + ASTContext *Context; + + /// \brief The AST consumer. + ASTConsumer *Consumer; + + /// \brief The bitstream reader from which we'll read the PCH file. + llvm::BitstreamReader StreamFile; + llvm::BitstreamCursor Stream; + + /// DeclsCursor - This is a cursor to the start of the DECLS_BLOCK block. It + /// has read all the abbreviations at the start of the block and is ready to + /// jump around with these in context. + llvm::BitstreamCursor DeclsCursor; + + /// \brief The file name of the PCH file. + std::string FileName; + + /// \brief The memory buffer that stores the data associated with + /// this PCH file. + llvm::OwningPtr<llvm::MemoryBuffer> Buffer; + + /// \brief Offset type for all of the source location entries in the + /// PCH file. + const uint32_t *SLocOffsets; + + /// \brief The number of source location entries in the PCH file. + unsigned TotalNumSLocEntries; + + /// \brief Cursor used to read source location entries. + llvm::BitstreamCursor SLocEntryCursor; + + /// \brief Offset of each type within the bitstream, indexed by the + /// type ID, or the representation of a Type*. + const uint32_t *TypeOffsets; + + /// \brief Types that have already been loaded from the PCH file. + /// + /// When the pointer at index I is non-NULL, the type with + /// ID = (I + 1) << 3 has already been loaded from the PCH file. + std::vector<Type *> TypesLoaded; + + /// \brief Offset of each declaration within the bitstream, indexed + /// by the declaration ID (-1). + const uint32_t *DeclOffsets; + + /// \brief Declarations that have already been loaded from the PCH file. + /// + /// When the pointer at index I is non-NULL, the declaration with ID + /// = I + 1 has already been loaded. + std::vector<Decl *> DeclsLoaded; + + typedef llvm::DenseMap<const DeclContext *, std::pair<uint64_t, uint64_t> > + DeclContextOffsetsMap; + + /// \brief Offsets of the lexical and visible declarations for each + /// DeclContext. + DeclContextOffsetsMap DeclContextOffsets; + + /// \brief Actual data for the on-disk hash table. + /// + // This pointer points into a memory buffer, where the on-disk hash + // table for identifiers actually lives. + const char *IdentifierTableData; + + /// \brief A pointer to an on-disk hash table of opaque type + /// IdentifierHashTable. + void *IdentifierLookupTable; + + /// \brief Offsets into the identifier table data. + /// + /// This array is indexed by the identifier ID (-1), and provides + /// the offset into IdentifierTableData where the string data is + /// stored. + const uint32_t *IdentifierOffsets; + + /// \brief A vector containing identifiers that have already been + /// loaded. + /// + /// If the pointer at index I is non-NULL, then it refers to the + /// IdentifierInfo for the identifier with ID=I+1 that has already + /// been loaded. + std::vector<IdentifierInfo *> IdentifiersLoaded; + + /// \brief A pointer to an on-disk hash table of opaque type + /// PCHMethodPoolLookupTable. + /// + /// This hash table provides the instance and factory methods + /// associated with every selector known in the PCH file. + void *MethodPoolLookupTable; + + /// \brief A pointer to the character data that comprises the method + /// pool. + /// + /// The SelectorOffsets table refers into this memory. + const unsigned char *MethodPoolLookupTableData; + + /// \brief The number of selectors stored in the method pool itself. + unsigned TotalSelectorsInMethodPool; + + /// \brief Offsets into the method pool lookup table's data array + /// where each selector resides. + const uint32_t *SelectorOffsets; + + /// \brief The total number of selectors stored in the PCH file. + unsigned TotalNumSelectors; + + /// \brief A vector containing selectors that have already been loaded. + /// + /// This vector is indexed by the Selector ID (-1). NULL selector + /// entries indicate that the particular selector ID has not yet + /// been loaded. + llvm::SmallVector<Selector, 16> SelectorsLoaded; + + /// \brief The set of external definitions stored in the the PCH + /// file. + llvm::SmallVector<uint64_t, 16> ExternalDefinitions; + + /// \brief The set of tentative definitions stored in the the PCH + /// file. + llvm::SmallVector<uint64_t, 16> TentativeDefinitions; + + /// \brief The set of locally-scoped external declarations stored in + /// the the PCH file. + llvm::SmallVector<uint64_t, 16> LocallyScopedExternalDecls; + + /// \brief The set of ext_vector type declarations stored in the the + /// PCH file. + llvm::SmallVector<uint64_t, 4> ExtVectorDecls; + + /// \brief The set of Objective-C category definitions stored in the + /// the PCH file. + llvm::SmallVector<uint64_t, 4> ObjCCategoryImpls; + + /// \brief The original file name that was used to build the PCH + /// file. + std::string OriginalFileName; + + /// \brief Mapping from switch-case IDs in the PCH file to + /// switch-case statements. + std::map<unsigned, SwitchCase *> SwitchCaseStmts; + + /// \brief Mapping from label statement IDs in the PCH file to label + /// statements. + std::map<unsigned, LabelStmt *> LabelStmts; + + /// \brief Mapping from label IDs to the set of "goto" statements + /// that point to that label before the label itself has been + /// de-serialized. + std::multimap<unsigned, GotoStmt *> UnresolvedGotoStmts; + + /// \brief Mapping from label IDs to the set of address label + /// expressions that point to that label before the label itself has + /// been de-serialized. + std::multimap<unsigned, AddrLabelExpr *> UnresolvedAddrLabelExprs; + + /// \brief The number of stat() calls that hit/missed the stat + /// cache. + unsigned NumStatHits, NumStatMisses; + + /// \brief The number of source location entries de-serialized from + /// the PCH file. + unsigned NumSLocEntriesRead; + + /// \brief The number of statements (and expressions) de-serialized + /// from the PCH file. + unsigned NumStatementsRead; + + /// \brief The total number of statements (and expressions) stored + /// in the PCH file. + unsigned TotalNumStatements; + + /// \brief The number of macros de-serialized from the PCH file. + unsigned NumMacrosRead; + + /// \brief The number of method pool entries that have been read. + unsigned NumMethodPoolSelectorsRead; + + /// \brief The number of times we have looked into the global method + /// pool and not found anything. + unsigned NumMethodPoolMisses; + + /// \brief The total number of macros stored in the PCH file. + unsigned TotalNumMacros; + + /// Number of lexical decl contexts read/total. + unsigned NumLexicalDeclContextsRead, TotalLexicalDeclContexts; + + /// Number of visible decl contexts read/total. + unsigned NumVisibleDeclContextsRead, TotalVisibleDeclContexts; + + /// \brief FIXME: document! + llvm::SmallVector<uint64_t, 4> SpecialTypes; + + /// \brief Contains declarations and definitions that will be + /// "interesting" to the ASTConsumer, when we get that AST consumer. + /// + /// "Interesting" declarations are those that have data that may + /// need to be emitted, such as inline function definitions or + /// Objective-C protocols. + llvm::SmallVector<Decl *, 16> InterestingDecls; + + /// \brief The file ID for the predefines buffer in the PCH file. + FileID PCHPredefinesBufferID; + + /// \brief Pointer to the beginning of the predefines buffer in the + /// PCH file. + const char *PCHPredefines; + + /// \brief Length of the predefines buffer in the PCH file. + unsigned PCHPredefinesLen; + + /// \brief Suggested contents of the predefines buffer, after this + /// PCH file has been processed. + /// + /// In most cases, this string will be empty, because the predefines + /// buffer computed to build the PCH file will be identical to the + /// predefines buffer computed from the command line. However, when + /// there are differences that the PCH reader can work around, this + /// predefines buffer may contain additional definitions. + std::string SuggestedPredefines; + + PCHReadResult ReadPCHBlock(); + bool CheckPredefinesBuffer(const char *PCHPredef, + unsigned PCHPredefLen, + FileID PCHBufferID); + PCHReadResult ReadSourceManagerBlock(); + PCHReadResult ReadSLocEntryRecord(unsigned ID); + + bool ParseLanguageOptions(const llvm::SmallVectorImpl<uint64_t> &Record); + QualType ReadTypeRecord(uint64_t Offset); + void LoadedDecl(unsigned Index, Decl *D); + Decl *ReadDeclRecord(uint64_t Offset, unsigned Index); + + /// \brief Produce an error diagnostic and return true. + /// + /// This routine should only be used for fatal errors that have to + /// do with non-routine failures (e.g., corrupted PCH file). + bool Error(const char *Msg); + + PCHReader(const PCHReader&); // do not implement + PCHReader &operator=(const PCHReader &); // do not implement + +public: + typedef llvm::SmallVector<uint64_t, 64> RecordData; + + explicit PCHReader(Preprocessor &PP, ASTContext *Context); + ~PCHReader(); + + /// \brief Load the precompiled header designated by the given file + /// name. + PCHReadResult ReadPCH(const std::string &FileName); + + /// \brief Retrieve the name of the original source file name + const std::string &getOriginalSourceFile() { return OriginalFileName; } + + /// \brief Retrieve the name of the original source file name + /// directly from the PCH file, without actually loading the PCH + /// file. + static std::string getOriginalSourceFile(const std::string &PCHFileName); + + /// \brief Returns the suggested contents of the predefines buffer, + /// which contains a (typically-empty) subset of the predefines + /// build prior to including the precompiled header. + const std::string &getSuggestedPredefines() { return SuggestedPredefines; } + + /// \brief Resolve a type ID into a type, potentially building a new + /// type. + virtual QualType GetType(pch::TypeID ID); + + /// \brief Resolve a declaration ID into a declaration, potentially + /// building a new declaration. + virtual Decl *GetDecl(pch::DeclID ID); + + /// \brief Resolve the offset of a statement into a statement. + /// + /// This operation will read a new statement from the external + /// source each time it is called, and is meant to be used via a + /// LazyOffsetPtr (which is used by Decls for the body of functions, etc). + virtual Stmt *GetDeclStmt(uint64_t Offset); + + /// ReadBlockAbbrevs - Enter a subblock of the specified BlockID with the + /// specified cursor. Read the abbreviations that are at the top of the block + /// and then leave the cursor pointing into the block. + bool ReadBlockAbbrevs(llvm::BitstreamCursor &Cursor, unsigned BlockID); + + /// \brief Read all of the declarations lexically stored in a + /// declaration context. + /// + /// \param DC The declaration context whose declarations will be + /// read. + /// + /// \param Decls Vector that will contain the declarations loaded + /// from the external source. The caller is responsible for merging + /// these declarations with any declarations already stored in the + /// declaration context. + /// + /// \returns true if there was an error while reading the + /// declarations for this declaration context. + virtual bool ReadDeclsLexicallyInContext(DeclContext *DC, + llvm::SmallVectorImpl<pch::DeclID> &Decls); + + /// \brief Read all of the declarations visible from a declaration + /// context. + /// + /// \param DC The declaration context whose visible declarations + /// will be read. + /// + /// \param Decls A vector of visible declaration structures, + /// providing the mapping from each name visible in the declaration + /// context to the declaration IDs of declarations with that name. + /// + /// \returns true if there was an error while reading the + /// declarations for this declaration context. + /// + /// FIXME: Using this intermediate data structure results in an + /// extraneous copying of the data. Could we pass in a reference to + /// the StoredDeclsMap instead? + virtual bool ReadDeclsVisibleInContext(DeclContext *DC, + llvm::SmallVectorImpl<VisibleDeclaration> & Decls); + + /// \brief Function that will be invoked when we begin parsing a new + /// translation unit involving this external AST source. + /// + /// This function will provide all of the external definitions to + /// the ASTConsumer. + virtual void StartTranslationUnit(ASTConsumer *Consumer); + + /// \brief Print some statistics about PCH usage. + virtual void PrintStats(); + + /// \brief Initialize the semantic source with the Sema instance + /// being used to perform semantic analysis on the abstract syntax + /// tree. + virtual void InitializeSema(Sema &S); + + /// \brief Retrieve the IdentifierInfo for the named identifier. + /// + /// This routine builds a new IdentifierInfo for the given + /// identifier. If any declarations with this name are visible from + /// translation unit scope, their declarations will be deserialized + /// and introduced into the declaration chain of the + /// identifier. FIXME: if this identifier names a macro, deserialize + /// the macro. + virtual IdentifierInfo* get(const char *NameStart, const char *NameEnd); + + /// \brief Load the contents of the global method pool for a given + /// selector. + /// + /// \returns a pair of Objective-C methods lists containing the + /// instance and factory methods, respectively, with this selector. + virtual std::pair<ObjCMethodList, ObjCMethodList> + ReadMethodPool(Selector Sel); + + void SetIdentifierInfo(unsigned ID, IdentifierInfo *II); + + /// \brief Report a diagnostic. + DiagnosticBuilder Diag(unsigned DiagID); + + /// \brief Report a diagnostic. + DiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID); + + IdentifierInfo *DecodeIdentifierInfo(unsigned Idx); + + IdentifierInfo *GetIdentifierInfo(const RecordData &Record, unsigned &Idx) { + return DecodeIdentifierInfo(Record[Idx++]); + } + + virtual IdentifierInfo *GetIdentifier(unsigned ID) { + return DecodeIdentifierInfo(ID); + } + + /// \brief Read the source location entry with index ID. + virtual void ReadSLocEntry(unsigned ID); + + Selector DecodeSelector(unsigned Idx); + + Selector GetSelector(const RecordData &Record, unsigned &Idx) { + return DecodeSelector(Record[Idx++]); + } + DeclarationName ReadDeclarationName(const RecordData &Record, unsigned &Idx); + + /// \brief Read an integral value + llvm::APInt ReadAPInt(const RecordData &Record, unsigned &Idx); + + /// \brief Read a signed integral value + llvm::APSInt ReadAPSInt(const RecordData &Record, unsigned &Idx); + + /// \brief Read a floating-point value + llvm::APFloat ReadAPFloat(const RecordData &Record, unsigned &Idx); + + // \brief Read a string + std::string ReadString(const RecordData &Record, unsigned &Idx); + + /// \brief Reads attributes from the current stream position. + Attr *ReadAttributes(); + + /// \brief ReadDeclExpr - Reads an expression from the current decl cursor. + Expr *ReadDeclExpr(); + + /// \brief ReadTypeExpr - Reads an expression from the current type cursor. + Expr *ReadTypeExpr(); + + /// \brief Reads a statement from the specified cursor. + Stmt *ReadStmt(llvm::BitstreamCursor &Cursor); + + /// \brief Read a statement from the current DeclCursor. + Stmt *ReadDeclStmt() { + return ReadStmt(DeclsCursor); + } + + /// \brief Reads the macro record located at the given offset. + void ReadMacroRecord(uint64_t Offset); + + /// \brief Retrieve the AST context that this PCH reader + /// supplements. + ASTContext *getContext() { return Context; } + + // \brief Contains declarations that were loaded before we have + // access to a Sema object. + llvm::SmallVector<NamedDecl *, 16> PreloadedDecls; + + /// \brief Retrieve the semantic analysis object used to analyze the + /// translation unit in which the precompiled header is being + /// imported. + Sema *getSema() { return SemaObj; } + + /// \brief Retrieve the stream that this PCH reader is reading from. + llvm::BitstreamCursor &getStream() { return Stream; } + llvm::BitstreamCursor &getDeclsCursor() { return DeclsCursor; } + + /// \brief Retrieve the identifier table associated with the + /// preprocessor. + IdentifierTable &getIdentifierTable(); + + /// \brief Record that the given ID maps to the given switch-case + /// statement. + void RecordSwitchCaseID(SwitchCase *SC, unsigned ID); + + /// \brief Retrieve the switch-case statement with the given ID. + SwitchCase *getSwitchCaseWithID(unsigned ID); + + /// \brief Record that the given label statement has been + /// deserialized and has the given ID. + void RecordLabelStmt(LabelStmt *S, unsigned ID); + + /// \brief Set the label of the given statement to the label + /// identified by ID. + /// + /// Depending on the order in which the label and other statements + /// referencing that label occur, this operation may complete + /// immediately (updating the statement) or it may queue the + /// statement to be back-patched later. + void SetLabelOf(GotoStmt *S, unsigned ID); + + /// \brief Set the label of the given expression to the label + /// identified by ID. + /// + /// Depending on the order in which the label and other statements + /// referencing that label occur, this operation may complete + /// immediately (updating the statement) or it may queue the + /// statement to be back-patched later. + void SetLabelOf(AddrLabelExpr *S, unsigned ID); +}; + +/// \brief Helper class that saves the current stream position and +/// then restores it when destroyed. +struct SavedStreamPosition { + explicit SavedStreamPosition(llvm::BitstreamCursor &Cursor) + : Cursor(Cursor), Offset(Cursor.GetCurrentBitNo()) { } + + ~SavedStreamPosition() { + Cursor.JumpToBit(Offset); + } + +private: + llvm::BitstreamCursor &Cursor; + uint64_t Offset; +}; + +} // end namespace clang + +#endif |
