diff --git a/lib/Bytecode/Reader/Reader.h b/lib/Bytecode/Reader/Reader.h new file mode 100644 index 00000000000..a5827589b48 --- /dev/null +++ b/lib/Bytecode/Reader/Reader.h @@ -0,0 +1,470 @@ +//===-- Reader.h - Interface To Bytecode Reading ----------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file was developed by Reid Spencer and is distributed under the +// University of Illinois Open Source License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This header file defines the interface to the Bytecode Reader which is +// responsible for correctly interpreting bytecode files (backwards compatible) +// and materializing a module from the bytecode read. +// +//===----------------------------------------------------------------------===// + +#ifndef BYTECODE_PARSER_H +#define BYTECODE_PARSER_H + +#include "llvm/Constants.h" +#include "llvm/DerivedTypes.h" +#include "llvm/GlobalValue.h" +#include "llvm/Function.h" +#include "llvm/ModuleProvider.h" +#include +#include + +namespace llvm { + +class BytecodeHandler; ///< Forward declare the handler interface + +/// This class defines the interface for parsing a buffer of bytecode. The +/// parser itself takes no action except to call the various functions of +/// the handler interface. The parser's sole responsibility is the correct +/// interpretation of the bytecode buffer. The handler is responsible for +/// instantiating and keeping track of all values. As a convenience, the parser +/// is responsible for materializing types and will pass them through the +/// handler interface as necessary. +/// @see BytecodeHandler +/// @brief Bytecode Reader interface +class BytecodeReader : public ModuleProvider { + +/// @name Constructors +/// @{ +public: + /// @brief Default constructor. By default, no handler is used. + BytecodeReader( + BytecodeHandler* h = 0 + ) { + Handler = h; + } + + ~BytecodeReader() { freeState(); } + +/// @} +/// @name Types +/// @{ +public: + /// @brief A convenience type for the buffer pointer + typedef const unsigned char* BufPtr; + + /// @brief The type used for a vector of potentially abstract types + typedef std::vector TypeListTy; + + /// This type provides a vector of Value* via the User class for + /// storage of Values that have been constructed when reading the + /// bytecode. Because of forward referencing, constant replacement + /// can occur so we ensure that our list of Value* is updated + /// properly through those transitions. This ensures that the + /// correct Value* is in our list when it comes time to associate + /// constants with global variables at the end of reading the + /// globals section. + /// @brief A list of values as a User of those Values. + struct ValueList : public User { + ValueList() : User(Type::TypeTy, Value::TypeVal) {} + + // vector compatibility methods + unsigned size() const { return getNumOperands(); } + void push_back(Value *V) { Operands.push_back(Use(V, this)); } + Value *back() const { return Operands.back(); } + void pop_back() { Operands.pop_back(); } + bool empty() const { return Operands.empty(); } + // must override this + virtual void print(std::ostream& os) const { + for ( unsigned i = 0; i < size(); i++ ) { + os << i << " "; + getOperand(i)->print(os); + os << "\n"; + } + } + }; + + /// @brief A 2 dimensional table of values + typedef std::vector ValueTable; + + /// This map is needed so that forward references to constants can be looked + /// up by Type and slot number when resolving those references. + /// @brief A mapping of a Type/slot pair to a Constant*. + typedef std::map, Constant*> ConstantRefsType; + + /// For lazy read-in of functions, we need to save the location in the + /// data stream where the function is located. This structure provides that + /// information. Lazy read-in is used mostly by the JIT which only wants to + /// resolve functions as it needs them. + /// @brief Keeps pointers to function contents for later use. + struct LazyFunctionInfo { + const unsigned char *Buf, *EndBuf; + LazyFunctionInfo(const unsigned char *B = 0, const unsigned char *EB = 0) + : Buf(B), EndBuf(EB) {} + }; + + /// @brief A mapping of functions to their LazyFunctionInfo for lazy reading. + typedef std::map LazyFunctionMap; + + /// @brief A list of global variables and the slot number that initializes + /// them. + typedef std::vector > GlobalInitsList; + + /// This type maps a typeslot/valueslot pair to the corresponding Value*. + /// It is used for dealing with forward references as values are read in. + /// @brief A map for dealing with forward references of values. + typedef std::map,Value*> ForwardReferenceMap; + +/// @} +/// @name Methods +/// @{ +public: + /// This function completely parses a bytecode buffer given by the \p Buf + /// and \p Length parameters. The + /// @brief Main interface to parsing a bytecode buffer. + void ParseBytecode( + const unsigned char *Buf, ///< Beginning of the bytecode buffer + unsigned Length, ///< Length of the bytecode buffer + const std::string &ModuleID ///< An identifier for the module constructed. + ); + + /// The ParseAllFunctionBodies method parses through all the previously + /// unparsed functions in the bytecode file. If you want to completely parse + /// a bytecode file, this method should be called after Parsebytecode because + /// Parsebytecode only records the locations in the bytecode file of where + /// the function definitions are located. This function uses that information + /// to materialize the functions. + /// @see ParseBytecode + /// @brief Parse all function bodies + void ParseAllFunctionBodies (); + + /// The ParserFunction method lazily parses one function. Use this method to + /// casue the parser to parse a specific function in the module. Note that + /// this will remove the function from what is to be included by + /// ParseAllFunctionBodies. + /// @see ParseAllFunctionBodies + /// @see ParseBytecode + /// @brief Parse the next function of specific type + void ParseFunction (Function* Func) ; + + /// This method is abstract in the parent ModuleProvider class. Its + /// implementation is identical to the ParseFunction method. + /// @see ParseFunction + /// @brief Make a specific function materialize. + virtual void materializeFunction(Function *F) { + LazyFunctionMap::iterator Fi = LazyFunctionLoadMap.find(F); + if (Fi == LazyFunctionLoadMap.end()) return; + ParseFunction(F); + } + + /// This method is abstract in the parent ModuleProvider class. Its + /// implementation is identical to ParseAllFunctionBodies. + /// @see ParseAllFunctionBodies + /// @brief Make the whole module materialize + virtual Module* materializeModule() { + ParseAllFunctionBodies(); + return TheModule; + } + + /// This method is provided by the parent ModuleProvde class and overriden + /// here. It simply releases the module from its provided and frees up our + /// state. + /// @brief Release our hold on the generated module + Module* releaseModule() { + // Since we're losing control of this Module, we must hand it back complete + Module *M = ModuleProvider::releaseModule(); + freeState(); + return M; + } + +/// @} +/// @name Parsing Units For Subclasses +/// @{ +protected: + /// @brief Parse whole module scope + void ParseModule(); + + /// @brief Parse the version information block + void ParseVersionInfo(); + + /// @brief Parse the ModuleGlobalInfo block + void ParseModuleGlobalInfo(); + + /// @brief Parse a symbol table + void ParseSymbolTable( Function* Func, SymbolTable *ST); + + /// This function parses LLVM functions lazily. It obtains the type of the + /// function and records where the body of the function is in the bytecode + /// buffer. The caller can then use the ParseNextFunction and + /// ParseAllFunctionBodies to get handler events for the functions. + /// @brief Parse functions lazily. + void ParseFunctionLazily(); + + /// @brief Parse a function body + void ParseFunctionBody(Function* Func); + + /// @brief Parse a compaction table + void ParseCompactionTable(); + + /// @brief Parse global types + void ParseGlobalTypes(); + + /// @returns The basic block constructed. + /// @brief Parse a basic block (for LLVM 1.0 basic block blocks) + BasicBlock* ParseBasicBlock(unsigned BlockNo); + + /// @returns Rhe number of basic blocks encountered. + /// @brief parse an instruction list (for post LLVM 1.0 instruction lists + /// with blocks differentiated by terminating instructions. + unsigned ParseInstructionList( + Function* F ///< The function into which BBs will be inserted + ); + + /// This method parses a single instruction. The instruction is + /// inserted at the end of the \p BB provided. The arguments of + /// the instruction are provided in the \p Args vector. + /// @brief Parse a single instruction. + void ParseInstruction( + std::vector& Args, ///< The arguments to be filled in + BasicBlock* BB ///< The BB the instruction goes in + ); + + /// @brief Parse the whole constant pool + void ParseConstantPool(ValueTable& Values, TypeListTy& Types); + + /// @brief Parse a single constant value + Constant* ParseConstantValue(unsigned TypeID); + + /// @brief Parse a block of types constants + void ParseTypeConstants(TypeListTy &Tab, unsigned NumEntries); + + /// @brief Parse a single type constant + const Type *ParseTypeConstant(); + + /// @brief Parse a string constants block + void ParseStringConstants(unsigned NumEntries, ValueTable &Tab); + +/// @} +/// @name Data +/// @{ +private: + BufPtr MemStart; ///< Start of the memory buffer + BufPtr MemEnd; ///< End of the memory buffer + BufPtr BlockStart; ///< Start of current block being parsed + BufPtr BlockEnd; ///< End of current block being parsed + BufPtr At; ///< Where we're currently parsing at + + // Information about the module, extracted from the bytecode revision number. + unsigned char RevisionNum; // The rev # itself + + // Flags to distinguish LLVM 1.0 & 1.1 bytecode formats (revision #0) + + // Revision #0 had an explicit alignment of data only for the ModuleGlobalInfo + // block. This was fixed to be like all other blocks in 1.2 + bool hasInconsistentModuleGlobalInfo; + + // Revision #0 also explicitly encoded zero values for primitive types like + // int/sbyte/etc. + bool hasExplicitPrimitiveZeros; + + // Flags to control features specific the LLVM 1.2 and before (revision #1) + + // LLVM 1.2 and earlier required that getelementptr structure indices were + // ubyte constants and that sequential type indices were longs. + bool hasRestrictedGEPTypes; + + /// CompactionTable - If a compaction table is active in the current function, + /// this is the mapping that it contains. + std::vector CompactionTypes; + + /// @brief If a compaction table is active in the current function, + /// this is the mapping that it contains. + std::vector > CompactionValues; + + /// @brief This vector is used to deal with forward references to types in + /// a module. + TypeListTy ModuleTypes; + + /// @brief This vector is used to deal with forward references to types in + /// a function. + TypeListTy FunctionTypes; + + /// When the ModuleGlobalInfo section is read, we create a Function object + /// for each function in the module. When the function is loaded, after the + /// module global info is read, this Function is populated. Until then, the + /// functions in this vector just hold the function signature. + std::vector FunctionSignatureList; + + /// @brief This is the table of values belonging to the current function + ValueTable FunctionValues; + + /// @brief This is the table of values belonging to the module (global) + ValueTable ModuleValues; + + /// @brief This keeps track of function level forward references. + ForwardReferenceMap ForwardReferences; + + /// @brief The basic blocks we've parsed, while parsing a function. + std::vector ParsedBasicBlocks; + + /// This maintains a mapping between 's and + /// forward references to constants. Such values may be referenced before they + /// are defined, and if so, the temporary object that they represent is held + /// here. + /// @brief Temporary place for forward references to constants. + ConstantRefsType ConstantFwdRefs; + + /// Constant values are read in after global variables. Because of this, we + /// must defer setting the initializers on global variables until after module + /// level constants have been read. In the mean time, this list keeps track of + /// what we must do. + GlobalInitsList GlobalInits; + + // For lazy reading-in of functions, we need to save away several pieces of + // information about each function: its begin and end pointer in the buffer + // and its FunctionSlot. + LazyFunctionMap LazyFunctionLoadMap; + + /// This stores the parser's handler which is used for handling tasks other + /// just than reading bytecode into the IR. If this is non-null, calls on + /// the (polymorphic) BytecodeHandler interface (see llvm/Bytecode/Handler.h) + /// will be made to report the logical structure of the bytecode file. What + /// the handler does with the events it receives is completely orthogonal to + /// the business of parsing the bytecode and building the IR. This is used, + /// for example, by the llvm-abcd tool for analysis of byte code. + /// @brief Handler for parsing events. + BytecodeHandler* Handler; + +/// @} +/// @name Implementation Details +/// @{ +private: + /// @brief Determines if this module has a function or not. + bool hasFunctions() { return ! FunctionSignatureList.empty(); } + + /// @brief Determines if the type id has an implicit null value. + bool hasImplicitNull(unsigned TyID ); + + /// @brief Converts a type slot number to its Type* + const Type *getType(unsigned ID); + + /// @brief Converts a Type* to its type slot number + unsigned getTypeSlot(const Type *Ty); + + /// @brief Converts a normal type slot number to a compacted type slot num. + unsigned getCompactionTypeSlot(unsigned type); + + /// This is just like getType, but when a compaction table is in use, it is + /// ignored. Also, no forward references or other fancy features are + /// supported. + const Type *getGlobalTableType(unsigned Slot); + + /// This is just like getTypeSlot, but when a compaction table is in use, + /// it is ignored. + unsigned getGlobalTableTypeSlot(const Type *Ty); + + /// Retrieve a value of a given type and slot number, possibly creating + /// it if it doesn't already exist. + Value* getValue(unsigned TypeID, unsigned num, bool Create = true); + + /// This is just like getValue, but when a compaction table is in use, it + /// is ignored. Also, no forward references or other fancy features are + /// supported. + Value *getGlobalTableValue(const Type *Ty, unsigned SlotNo); + + /// This function is used when construction phi, br, switch, and other + /// instructions that reference basic blocks. Blocks are numbered + /// sequentially as they appear in the function. + /// @brief Get a basic block for current function + BasicBlock *getBasicBlock(unsigned ID); + + /// Just like getValue, except that it returns a null pointer + /// only on error. It always returns a constant (meaning that if the value is + /// defined, but is not a constant, that is an error). If the specified + /// constant hasn't been parsed yet, a placeholder is defined and used. + /// Later, after the real value is parsed, the placeholder is eliminated. + Constant* getConstantValue(unsigned typeSlot, unsigned valSlot); + + /// @brief Convenience function for getting a constant value when + /// the Type has already been resolved. + Constant* getConstantValue(const Type *Ty, unsigned valSlot) { + return getConstantValue(getTypeSlot(Ty), valSlot); + } + + /// As values are created, they are inserted into the appropriate place + /// with this method. The ValueTable argument must be one of ModuleValues + /// or FunctionValues data members of this class. + /// @brief Insert a newly created value + unsigned insertValue(Value *V, unsigned Type, ValueTable &Table); + + /// @brief Insert the arguments of a function. + void insertArguments(Function* F ); + + /// @brief Resolve all references to the placeholder (if any) for the + /// given constant. + void ResolveReferencesToConstant(Constant *C, unsigned Slot); + + /// @brief Release our memory. + void freeState() { + freeTable(FunctionValues); + freeTable(ModuleValues); + } + + /// @brief Free a table, making sure to free the ValueList in the table. + void freeTable(ValueTable &Tab) { + while (!Tab.empty()) { + delete Tab.back(); + Tab.pop_back(); + } + } + + BytecodeReader(const BytecodeReader &); // DO NOT IMPLEMENT + void operator=(const BytecodeReader &); // DO NOT IMPLEMENT + +/// @} +/// @name Reader Primitives +/// @{ +private: + + /// @brief Is there more to parse in the current block? + inline bool moreInBlock(); + + /// @brief Have we read past the end of the block + inline void checkPastBlockEnd(const char * block_name); + + /// @brief Align to 32 bits + inline void align32(); + + /// @brief Read an unsigned integer as 32-bits + inline unsigned read_uint(); + + /// @brief Read an unsigned integer with variable bit rate encoding + inline unsigned read_vbr_uint(); + + /// @brief Read an unsigned 64-bit integer with variable bit rate encoding. + inline uint64_t read_vbr_uint64(); + + /// @brief Read a signed 64-bit integer with variable bit rate encoding. + inline int64_t read_vbr_int64(); + + /// @brief Read a string + inline std::string read_str(); + + /// @brief Read an arbitrary data chunk of fixed length + inline void read_data(void *Ptr, void *End); + + /// Read a bytecode block header + inline void read_block(unsigned &Type, unsigned &Size); + +/// @} +}; + +} // End llvm namespace + +// vim: sw=2 +#endif