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e2a5fb0e08
bytecode reading. This code is crufty, the result of much hacking to get things working correctly. Cleanup patches will follow. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25682 91177308-0d34-0410-b5e6-96231b3b80d8
543 lines
20 KiB
C++
543 lines
20 KiB
C++
//===-- Reader.h - Interface To Bytecode Reading ----------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by Reid Spencer and is distributed under the
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// University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This header file defines the interface to the Bytecode Reader which is
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// responsible for correctly interpreting bytecode files (backwards compatible)
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// and materializing a module from the bytecode read.
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//
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//===----------------------------------------------------------------------===//
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#ifndef BYTECODE_PARSER_H
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#define BYTECODE_PARSER_H
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#include "llvm/Constants.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/GlobalValue.h"
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#include "llvm/Function.h"
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#include "llvm/ModuleProvider.h"
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#include "llvm/Bytecode/Analyzer.h"
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#include <utility>
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#include <map>
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namespace llvm {
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class BytecodeHandler; ///< Forward declare the handler interface
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/// This class defines the interface for parsing a buffer of bytecode. The
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/// parser itself takes no action except to call the various functions of
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/// the handler interface. The parser's sole responsibility is the correct
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/// interpretation of the bytecode buffer. The handler is responsible for
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/// instantiating and keeping track of all values. As a convenience, the parser
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/// is responsible for materializing types and will pass them through the
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/// handler interface as necessary.
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/// @see BytecodeHandler
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/// @brief Bytecode Reader interface
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class BytecodeReader : public ModuleProvider {
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/// @name Constructors
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/// @{
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public:
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/// @brief Default constructor. By default, no handler is used.
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BytecodeReader(BytecodeHandler* h = 0) {
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decompressedBlock = 0;
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Handler = h;
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}
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~BytecodeReader() {
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freeState();
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if (decompressedBlock) {
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::free(decompressedBlock);
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decompressedBlock = 0;
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}
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}
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/// @}
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/// @name Types
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/// @{
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public:
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/// @brief A convenience type for the buffer pointer
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typedef const unsigned char* BufPtr;
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/// @brief The type used for a vector of potentially abstract types
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typedef std::vector<PATypeHolder> TypeListTy;
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/// This type provides a vector of Value* via the User class for
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/// storage of Values that have been constructed when reading the
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/// bytecode. Because of forward referencing, constant replacement
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/// can occur so we ensure that our list of Value* is updated
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/// properly through those transitions. This ensures that the
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/// correct Value* is in our list when it comes time to associate
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/// constants with global variables at the end of reading the
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/// globals section.
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/// @brief A list of values as a User of those Values.
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class ValueList : public User {
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std::vector<Use> Uses;
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public:
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ValueList() : User(Type::VoidTy, Value::ArgumentVal, 0, 0) {}
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// vector compatibility methods
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unsigned size() const { return getNumOperands(); }
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void push_back(Value *V) {
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Uses.push_back(Use(V, this));
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OperandList = &Uses[0];
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++NumOperands;
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}
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Value *back() const { return Uses.back(); }
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void pop_back() { Uses.pop_back(); --NumOperands; }
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bool empty() const { return NumOperands == 0; }
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virtual void print(std::ostream& os) const {
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for (unsigned i = 0; i < size(); ++i) {
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os << i << " ";
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getOperand(i)->print(os);
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os << "\n";
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}
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}
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};
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/// @brief A 2 dimensional table of values
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typedef std::vector<ValueList*> ValueTable;
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/// This map is needed so that forward references to constants can be looked
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/// up by Type and slot number when resolving those references.
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/// @brief A mapping of a Type/slot pair to a Constant*.
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typedef std::map<std::pair<unsigned,unsigned>, Constant*> ConstantRefsType;
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/// For lazy read-in of functions, we need to save the location in the
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/// data stream where the function is located. This structure provides that
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/// information. Lazy read-in is used mostly by the JIT which only wants to
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/// resolve functions as it needs them.
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/// @brief Keeps pointers to function contents for later use.
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struct LazyFunctionInfo {
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const unsigned char *Buf, *EndBuf;
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LazyFunctionInfo(const unsigned char *B = 0, const unsigned char *EB = 0)
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: Buf(B), EndBuf(EB) {}
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};
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/// @brief A mapping of functions to their LazyFunctionInfo for lazy reading.
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typedef std::map<Function*, LazyFunctionInfo> LazyFunctionMap;
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/// @brief A list of global variables and the slot number that initializes
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/// them.
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typedef std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInitsList;
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/// This type maps a typeslot/valueslot pair to the corresponding Value*.
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/// It is used for dealing with forward references as values are read in.
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/// @brief A map for dealing with forward references of values.
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typedef std::map<std::pair<unsigned,unsigned>,Value*> ForwardReferenceMap;
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/// @}
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/// @name Methods
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/// @{
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public:
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/// @brief Main interface to parsing a bytecode buffer.
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void ParseBytecode(
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const unsigned char *Buf, ///< Beginning of the bytecode buffer
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unsigned Length, ///< Length of the bytecode buffer
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const std::string &ModuleID ///< An identifier for the module constructed.
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);
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/// @brief Parse all function bodies
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void ParseAllFunctionBodies();
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/// @brief Parse the next function of specific type
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void ParseFunction(Function* Func) ;
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/// This method is abstract in the parent ModuleProvider class. Its
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/// implementation is identical to the ParseFunction method.
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/// @see ParseFunction
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/// @brief Make a specific function materialize.
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virtual void materializeFunction(Function *F) {
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LazyFunctionMap::iterator Fi = LazyFunctionLoadMap.find(F);
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if (Fi == LazyFunctionLoadMap.end()) return;
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ParseFunction(F);
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}
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/// This method is abstract in the parent ModuleProvider class. Its
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/// implementation is identical to ParseAllFunctionBodies.
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/// @see ParseAllFunctionBodies
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/// @brief Make the whole module materialize
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virtual Module* materializeModule() {
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ParseAllFunctionBodies();
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return TheModule;
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}
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/// This method is provided by the parent ModuleProvde class and overriden
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/// here. It simply releases the module from its provided and frees up our
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/// state.
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/// @brief Release our hold on the generated module
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Module* releaseModule() {
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// Since we're losing control of this Module, we must hand it back complete
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Module *M = ModuleProvider::releaseModule();
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freeState();
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return M;
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}
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/// @}
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/// @name Parsing Units For Subclasses
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/// @{
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protected:
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/// @brief Parse whole module scope
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void ParseModule();
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/// @brief Parse the version information block
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void ParseVersionInfo();
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/// @brief Parse the ModuleGlobalInfo block
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void ParseModuleGlobalInfo();
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/// @brief Parse a symbol table
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void ParseSymbolTable( Function* Func, SymbolTable *ST);
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/// @brief Parse functions lazily.
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void ParseFunctionLazily();
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/// @brief Parse a function body
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void ParseFunctionBody(Function* Func);
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/// @brief Parse the type list portion of a compaction table
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void ParseCompactionTypes(unsigned NumEntries);
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/// @brief Parse a compaction table
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void ParseCompactionTable();
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/// @brief Parse global types
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void ParseGlobalTypes();
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/// @brief Parse a basic block (for LLVM 1.0 basic block blocks)
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BasicBlock* ParseBasicBlock(unsigned BlockNo);
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/// @brief parse an instruction list (for post LLVM 1.0 instruction lists
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/// with blocks differentiated by terminating instructions.
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unsigned ParseInstructionList(
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Function* F ///< The function into which BBs will be inserted
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);
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/// @brief Parse a single instruction.
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void ParseInstruction(
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std::vector<unsigned>& Args, ///< The arguments to be filled in
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BasicBlock* BB ///< The BB the instruction goes in
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);
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/// @brief Parse the whole constant pool
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void ParseConstantPool(ValueTable& Values, TypeListTy& Types,
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bool isFunction);
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/// @brief Parse a single constant pool value
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Value *ParseConstantPoolValue(unsigned TypeID);
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/// @brief Parse a block of types constants
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void ParseTypes(TypeListTy &Tab, unsigned NumEntries);
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/// @brief Parse a single type constant
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const Type *ParseType();
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/// @brief Parse a string constants block
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void ParseStringConstants(unsigned NumEntries, ValueTable &Tab);
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/// @}
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/// @name Data
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/// @{
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private:
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char* decompressedBlock; ///< Result of decompression
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BufPtr MemStart; ///< Start of the memory buffer
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BufPtr MemEnd; ///< End of the memory buffer
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BufPtr BlockStart; ///< Start of current block being parsed
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BufPtr BlockEnd; ///< End of current block being parsed
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BufPtr At; ///< Where we're currently parsing at
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/// Information about the module, extracted from the bytecode revision number.
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///
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unsigned char RevisionNum; // The rev # itself
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/// Flags to distinguish LLVM 1.0 & 1.1 bytecode formats (revision #0)
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/// Revision #0 had an explicit alignment of data only for the
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/// ModuleGlobalInfo block. This was fixed to be like all other blocks in 1.2
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bool hasInconsistentModuleGlobalInfo;
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/// Revision #0 also explicitly encoded zero values for primitive types like
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/// int/sbyte/etc.
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bool hasExplicitPrimitiveZeros;
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// Flags to control features specific the LLVM 1.2 and before (revision #1)
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/// LLVM 1.2 and earlier required that getelementptr structure indices were
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/// ubyte constants and that sequential type indices were longs.
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bool hasRestrictedGEPTypes;
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/// LLVM 1.2 and earlier had class Type deriving from Value and the Type
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/// objects were located in the "Type Type" plane of various lists in read
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/// by the bytecode reader. In LLVM 1.3 this is no longer the case. Types are
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/// completely distinct from Values. Consequently, Types are written in fixed
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/// locations in LLVM 1.3. This flag indicates that the older Type derived
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/// from Value style of bytecode file is being read.
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bool hasTypeDerivedFromValue;
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/// LLVM 1.2 and earlier encoded block headers as two uint (8 bytes), one for
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/// the size and one for the type. This is a bit wasteful, especially for
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/// small files where the 8 bytes per block is a large fraction of the total
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/// block size. In LLVM 1.3, the block type and length are encoded into a
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/// single uint32 by restricting the number of block types (limit 31) and the
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/// maximum size of a block (limit 2^27-1=134,217,727). Note that the module
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/// block still uses the 8-byte format so the maximum size of a file can be
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/// 2^32-1 bytes long.
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bool hasLongBlockHeaders;
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/// LLVM 1.2 and earlier wrote type slot numbers as vbr_uint32. In LLVM 1.3
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/// this has been reduced to vbr_uint24. It shouldn't make much difference
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/// since we haven't run into a module with > 24 million types, but for safety
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/// the 24-bit restriction has been enforced in 1.3 to free some bits in
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/// various places and to ensure consistency. In particular, global vars are
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/// restricted to 24-bits.
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bool has32BitTypes;
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/// LLVM 1.2 and earlier did not provide a target triple nor a list of
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/// libraries on which the bytecode is dependent. LLVM 1.3 provides these
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/// features, for use in future versions of LLVM.
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bool hasNoDependentLibraries;
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/// LLVM 1.3 and earlier caused blocks and other fields to start on 32-bit
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/// aligned boundaries. This can lead to as much as 30% bytecode size overhead
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/// in various corner cases (lots of long instructions). In LLVM 1.4,
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/// alignment of bytecode fields was done away with completely.
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bool hasAlignment;
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// In version 4 and earlier, the bytecode format did not support the 'undef'
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// constant.
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bool hasNoUndefValue;
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// In version 4 and earlier, the bytecode format did not save space for flags
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// in the global info block for functions.
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bool hasNoFlagsForFunctions;
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// In version 4 and earlier, there was no opcode space reserved for the
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// unreachable instruction.
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bool hasNoUnreachableInst;
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/// In release 1.7 we changed intrinsic functions to not be overloaded. There
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/// is no bytecode change for this, but to optimize the auto-upgrade of calls
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/// to intrinsic functions, we save a mapping of old function definitions to
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/// the new ones so call instructions can be upgraded efficiently.
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std::map<Function*,Function*> upgradedFunctions;
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/// CompactionTypes - If a compaction table is active in the current function,
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/// this is the mapping that it contains. We keep track of what resolved type
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/// it is as well as what global type entry it is.
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std::vector<std::pair<const Type*, unsigned> > CompactionTypes;
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/// @brief If a compaction table is active in the current function,
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/// this is the mapping that it contains.
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std::vector<std::vector<Value*> > CompactionValues;
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/// @brief This vector is used to deal with forward references to types in
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/// a module.
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TypeListTy ModuleTypes;
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/// @brief This is an inverse mapping of ModuleTypes from the type to an
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/// index. Because refining types causes the index of this map to be
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/// invalidated, any time we refine a type, we clear this cache and recompute
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/// it next time we need it. These entries are ordered by the pointer value.
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std::vector<std::pair<const Type*, unsigned> > ModuleTypeIDCache;
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/// @brief This vector is used to deal with forward references to types in
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/// a function.
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TypeListTy FunctionTypes;
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/// When the ModuleGlobalInfo section is read, we create a Function object
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/// for each function in the module. When the function is loaded, after the
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/// module global info is read, this Function is populated. Until then, the
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/// functions in this vector just hold the function signature.
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std::vector<Function*> FunctionSignatureList;
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/// @brief This is the table of values belonging to the current function
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ValueTable FunctionValues;
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/// @brief This is the table of values belonging to the module (global)
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ValueTable ModuleValues;
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/// @brief This keeps track of function level forward references.
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ForwardReferenceMap ForwardReferences;
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/// @brief The basic blocks we've parsed, while parsing a function.
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std::vector<BasicBlock*> ParsedBasicBlocks;
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/// This maintains a mapping between <Type, Slot #>'s and forward references
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/// to constants. Such values may be referenced before they are defined, and
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/// if so, the temporary object that they represent is held here. @brief
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/// Temporary place for forward references to constants.
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ConstantRefsType ConstantFwdRefs;
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/// Constant values are read in after global variables. Because of this, we
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/// must defer setting the initializers on global variables until after module
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/// level constants have been read. In the mean time, this list keeps track
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/// of what we must do.
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GlobalInitsList GlobalInits;
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// For lazy reading-in of functions, we need to save away several pieces of
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// information about each function: its begin and end pointer in the buffer
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// and its FunctionSlot.
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LazyFunctionMap LazyFunctionLoadMap;
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/// This stores the parser's handler which is used for handling tasks other
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/// just than reading bytecode into the IR. If this is non-null, calls on
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/// the (polymorphic) BytecodeHandler interface (see llvm/Bytecode/Handler.h)
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/// will be made to report the logical structure of the bytecode file. What
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/// the handler does with the events it receives is completely orthogonal to
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/// the business of parsing the bytecode and building the IR. This is used,
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/// for example, by the llvm-abcd tool for analysis of byte code.
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/// @brief Handler for parsing events.
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BytecodeHandler* Handler;
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/// @}
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/// @name Implementation Details
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/// @{
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private:
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/// @brief Determines if this module has a function or not.
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bool hasFunctions() { return ! FunctionSignatureList.empty(); }
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/// @brief Determines if the type id has an implicit null value.
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bool hasImplicitNull(unsigned TyID );
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/// @brief Converts a type slot number to its Type*
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const Type *getType(unsigned ID);
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/// @brief Converts a pre-sanitized type slot number to its Type* and
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/// sanitizes the type id.
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inline const Type* getSanitizedType(unsigned& ID );
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/// @brief Read in and get a sanitized type id
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inline const Type* readSanitizedType();
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/// @brief Converts a Type* to its type slot number
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unsigned getTypeSlot(const Type *Ty);
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/// @brief Converts a normal type slot number to a compacted type slot num.
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unsigned getCompactionTypeSlot(unsigned type);
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/// @brief Gets the global type corresponding to the TypeId
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const Type *getGlobalTableType(unsigned TypeId);
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/// This is just like getTypeSlot, but when a compaction table is in use,
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/// it is ignored.
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unsigned getGlobalTableTypeSlot(const Type *Ty);
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/// @brief Get a value from its typeid and slot number
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Value* getValue(unsigned TypeID, unsigned num, bool Create = true);
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/// @brief Get a value from its type and slot number, ignoring compaction
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/// tables.
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Value *getGlobalTableValue(unsigned TyID, unsigned SlotNo);
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/// @brief Get a basic block for current function
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BasicBlock *getBasicBlock(unsigned ID);
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/// @brief Get a constant value from its typeid and value slot.
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Constant* getConstantValue(unsigned typeSlot, unsigned valSlot);
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/// @brief Convenience function for getting a constant value when
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/// the Type has already been resolved.
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Constant* getConstantValue(const Type *Ty, unsigned valSlot) {
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return getConstantValue(getTypeSlot(Ty), valSlot);
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}
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/// @brief Insert a newly created value
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unsigned insertValue(Value *V, unsigned Type, ValueTable &Table);
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/// @brief Insert the arguments of a function.
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void insertArguments(Function* F );
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/// @brief Resolve all references to the placeholder (if any) for the
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/// given constant.
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void ResolveReferencesToConstant(Constant *C, unsigned Typ, unsigned Slot);
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/// @brief Release our memory.
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void freeState() {
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freeTable(FunctionValues);
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freeTable(ModuleValues);
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}
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/// @brief Free a table, making sure to free the ValueList in the table.
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void freeTable(ValueTable &Tab) {
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while (!Tab.empty()) {
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delete Tab.back();
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Tab.pop_back();
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}
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}
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inline void error(std::string errmsg);
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BytecodeReader(const BytecodeReader &); // DO NOT IMPLEMENT
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void operator=(const BytecodeReader &); // DO NOT IMPLEMENT
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/// @}
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/// @name Reader Primitives
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/// @{
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private:
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/// @brief Is there more to parse in the current block?
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inline bool moreInBlock();
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/// @brief Have we read past the end of the block
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inline void checkPastBlockEnd(const char * block_name);
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/// @brief Align to 32 bits
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inline void align32();
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/// @brief Read an unsigned integer as 32-bits
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inline unsigned read_uint();
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/// @brief Read an unsigned integer with variable bit rate encoding
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inline unsigned read_vbr_uint();
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/// @brief Read an unsigned integer of no more than 24-bits with variable
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/// bit rate encoding.
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inline unsigned read_vbr_uint24();
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/// @brief Read an unsigned 64-bit integer with variable bit rate encoding.
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inline uint64_t read_vbr_uint64();
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/// @brief Read a signed 64-bit integer with variable bit rate encoding.
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inline int64_t read_vbr_int64();
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/// @brief Read a string
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inline std::string read_str();
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/// @brief Read a float value
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inline void read_float(float& FloatVal);
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/// @brief Read a double value
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inline void read_double(double& DoubleVal);
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/// @brief Read an arbitrary data chunk of fixed length
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inline void read_data(void *Ptr, void *End);
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/// @brief Read a bytecode block header
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inline void read_block(unsigned &Type, unsigned &Size);
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/// @brief Read a type identifier and sanitize it.
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inline bool read_typeid(unsigned &TypeId);
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/// @brief Recalculate type ID for pre 1.3 bytecode files.
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inline bool sanitizeTypeId(unsigned &TypeId );
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/// @}
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};
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/// @brief A function for creating a BytecodeAnalzer as a handler
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/// for the Bytecode reader.
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BytecodeHandler* createBytecodeAnalyzerHandler(BytecodeAnalysis& bca,
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std::ostream* output );
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} // End llvm namespace
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// vim: sw=2
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#endif
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