llvm-6502/lib/Bytecode/Reader/Reader.h
Anton Korobeynikov a80e1181b7 Implement review feedback. Aliasees can be either GlobalValue's or
bitcasts of them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36537 91177308-0d34-0410-b5e6-96231b3b80d8
2007-04-28 13:45:00 +00:00

492 lines
18 KiB
C++

//===-- 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/ModuleProvider.h"
#include "llvm/Bytecode/Analyzer.h"
#include "llvm/ADT/SmallVector.h"
#include <utility>
#include <setjmp.h>
namespace llvm {
// Forward declarations
class BytecodeHandler;
class TypeSymbolTable;
class ValueSymbolTable;
/// 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) {
decompressedBlock = 0;
Handler = h;
}
~BytecodeReader() {
freeState();
if (decompressedBlock) {
::free(decompressedBlock);
decompressedBlock = 0;
}
}
/// @}
/// @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<PATypeHolder> 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.
class ValueList : public User {
SmallVector<Use, 32> Uses;
public:
ValueList() : User(Type::VoidTy, Value::ArgumentVal, 0, 0) {}
// vector compatibility methods
unsigned size() const { return getNumOperands(); }
void push_back(Value *V) {
Uses.push_back(Use(V, this));
OperandList = &Uses[0];
++NumOperands;
}
Value *back() const { return Uses.back(); }
void pop_back() { Uses.pop_back(); --NumOperands; }
bool empty() const { return NumOperands == 0; }
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<ValueList*> 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<std::pair<unsigned,unsigned>, 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<Function*, LazyFunctionInfo> LazyFunctionMap;
/// @brief A list of global variables and the slot number that initializes
/// them.
typedef std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInitsList;
/// @brief A list of global aliases and the slot number for constant aliasees
typedef std::vector<std::pair<GlobalAlias*, unsigned> > AliaseeList;
/// 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<std::pair<unsigned,unsigned>,Value*> ForwardReferenceMap;
/// @}
/// @name Methods
/// @{
public:
typedef size_t BCDecompressor_t(const char *, size_t, char*&, std::string*);
/// @returns true if an error occurred
/// @brief Main interface to parsing a bytecode buffer.
bool ParseBytecode(
volatile BufPtr Buf, ///< Beginning of the bytecode buffer
unsigned Length, ///< Length of the bytecode buffer
const std::string &ModuleID, ///< An identifier for the module constructed.
BCDecompressor_t *Decompressor = 0, ///< Optional decompressor.
std::string* ErrMsg = 0 ///< Optional place for error message
);
/// @brief Parse all function bodies
bool ParseAllFunctionBodies(std::string* ErrMsg);
/// @brief Parse the next function of specific type
bool ParseFunction(Function* Func, std::string* ErrMsg);
/// 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 bool materializeFunction(Function *F, std::string *ErrMsg = 0) {
// If it already is material, ignore the request.
if (!F->hasNotBeenReadFromBytecode()) return false;
assert(LazyFunctionLoadMap.count(F) &&
"not materialized but I don't know about it?");
if (ParseFunction(F,ErrMsg))
return true;
return false;
}
/// dematerializeFunction - If the given function is read in, and if the
/// module provider supports it, release the memory for the function, and set
/// it up to be materialized lazily. If the provider doesn't support this
/// capability, this method is a noop.
///
virtual void dematerializeFunction(Function *F) {
// If the function is not materialized, or if it is a prototype, ignore.
if (F->hasNotBeenReadFromBytecode() ||
F->isDeclaration())
return;
// Just forget the function body, we can remat it later.
F->deleteBody();
F->setLinkage(GlobalValue::GhostLinkage);
}
/// 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(std::string *ErrMsg = 0) {
if (ParseAllFunctionBodies(ErrMsg))
return 0;
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(std::string *ErrInfo = 0) {
// Since we're losing control of this Module, we must hand it back complete
Module *M = ModuleProvider::releaseModule(ErrInfo);
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 value symbol table
void ParseTypeSymbolTable(TypeSymbolTable *ST);
/// @brief Parse a value symbol table
void ParseValueSymbolTable(Function* Func, ValueSymbolTable *ST);
/// @brief Parse functions lazily.
void ParseFunctionLazily();
/// @brief Parse a function body
void ParseFunctionBody(Function* Func);
/// @brief Parse global types
void ParseGlobalTypes();
/// @brief Parse a basic block (for LLVM 1.0 basic block blocks)
BasicBlock* ParseBasicBlock(unsigned BlockNo);
/// @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
);
/// @brief Parse a single instruction.
void ParseInstruction(
SmallVector <unsigned, 8>& 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,
bool isFunction);
/// @brief Parse a single constant pool value
Value *ParseConstantPoolValue(unsigned TypeID);
/// @brief Parse a block of types constants
void ParseTypes(TypeListTy &Tab, unsigned NumEntries);
/// @brief Parse a single type constant
const Type *ParseType();
/// @brief Parse a list of parameter attributes
ParamAttrsList *ParseParamAttrsList();
/// @brief Parse a string constants block
void ParseStringConstants(unsigned NumEntries, ValueTable &Tab);
/// @brief Release our memory.
void freeState() {
freeTable(FunctionValues);
freeTable(ModuleValues);
}
/// @}
/// @name Data
/// @{
private:
std::string ErrorMsg; ///< A place to hold an error message through longjmp
jmp_buf context; ///< Where to return to if an error occurs.
char* decompressedBlock; ///< Result of decompression
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
/// @brief This vector is used to deal with forward references to types in
/// a module.
TypeListTy ModuleTypes;
/// @brief This is an inverse mapping of ModuleTypes from the type to an
/// index. Because refining types causes the index of this map to be
/// invalidated, any time we refine a type, we clear this cache and recompute
/// it next time we need it. These entries are ordered by the pointer value.
std::vector<std::pair<const Type*, unsigned> > ModuleTypeIDCache;
/// @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<Function*> 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<BasicBlock*> ParsedBasicBlocks;
/// This maintains a mapping between <Type, Slot #>'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;
/// Constant values are read in after global aliases. Because of this, we must
/// defer setting the constant aliasees until after module level constants
/// have been read. In the mean time, this list keeps track of what we must
/// do.
AliaseeList Aliasees;
// 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 Read in a type id and turn it into a Type*
inline const Type* readType();
/// @brief Converts a Type* to its type slot number
unsigned getTypeSlot(const Type *Ty);
/// @brief Gets the global type corresponding to the TypeId
const Type *getGlobalTableType(unsigned TypeId);
/// @brief Get a value from its typeid and slot number
Value* getValue(unsigned TypeID, unsigned num, bool Create = true);
/// @brief Get a basic block for current function
BasicBlock *getBasicBlock(unsigned ID);
/// @brief Get a constant value from its typeid and value slot.
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);
}
/// @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 Typ, unsigned Slot);
/// @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();
}
}
inline void error(const std::string& errmsg);
BytecodeReader(const BytecodeReader &); // DO NOT IMPLEMENT
void operator=(const BytecodeReader &); // DO NOT IMPLEMENT
// This enum provides the values of the well-known type slots that are always
// emitted as the first few types in the table by the BytecodeWriter class.
enum WellKnownTypeSlots {
VoidTypeSlot = 0, ///< TypeID == VoidTyID
FloatTySlot = 1, ///< TypeID == FloatTyID
DoubleTySlot = 2, ///< TypeID == DoubleTyID
LabelTySlot = 3, ///< TypeID == LabelTyID
BoolTySlot = 4, ///< TypeID == IntegerTyID, width = 1
Int8TySlot = 5, ///< TypeID == IntegerTyID, width = 8
Int16TySlot = 6, ///< TypeID == IntegerTyID, width = 16
Int32TySlot = 7, ///< TypeID == IntegerTyID, width = 32
Int64TySlot = 8 ///< TypeID == IntegerTyID, width = 64
};
/// @}
/// @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 integer of no more than 24-bits with variable
/// bit rate encoding.
inline unsigned read_vbr_uint24();
/// @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();
inline void read_str(SmallVectorImpl<char> &StrData);
/// @brief Read a float value
inline void read_float(float& FloatVal);
/// @brief Read a double value
inline void read_double(double& DoubleVal);
/// @brief Read an arbitrary data chunk of fixed length
inline void read_data(void *Ptr, void *End);
/// @brief Read a bytecode block header
inline void read_block(unsigned &Type, unsigned &Size);
/// @}
};
} // End llvm namespace
// vim: sw=2
#endif