1 //===-- Reader.h - Interface To Bytecode Reading ----------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Reid Spencer and is distributed under the
6 // University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This header file defines the interface to the Bytecode Reader which is
11 // responsible for correctly interpreting bytecode files (backwards compatible)
12 // and materializing a module from the bytecode read.
14 //===----------------------------------------------------------------------===//
16 #ifndef BYTECODE_PARSER_H
17 #define BYTECODE_PARSER_H
19 #include "llvm/Constants.h"
20 #include "llvm/DerivedTypes.h"
21 #include "llvm/GlobalValue.h"
22 #include "llvm/Function.h"
23 #include "llvm/ModuleProvider.h"
24 #include "llvm/Bytecode/Analyzer.h"
30 class BytecodeHandler; ///< Forward declare the handler interface
32 /// This class defines the interface for parsing a buffer of bytecode. The
33 /// parser itself takes no action except to call the various functions of
34 /// the handler interface. The parser's sole responsibility is the correct
35 /// interpretation of the bytecode buffer. The handler is responsible for
36 /// instantiating and keeping track of all values. As a convenience, the parser
37 /// is responsible for materializing types and will pass them through the
38 /// handler interface as necessary.
39 /// @see BytecodeHandler
40 /// @brief Bytecode Reader interface
41 class BytecodeReader : public ModuleProvider {
43 /// @name Constructors
46 /// @brief Default constructor. By default, no handler is used.
48 BytecodeHandler* h = 0
53 ~BytecodeReader() { freeState(); }
60 /// @brief A convenience type for the buffer pointer
61 typedef const unsigned char* BufPtr;
63 /// @brief The type used for a vector of potentially abstract types
64 typedef std::vector<PATypeHolder> TypeListTy;
66 /// This type provides a vector of Value* via the User class for
67 /// storage of Values that have been constructed when reading the
68 /// bytecode. Because of forward referencing, constant replacement
69 /// can occur so we ensure that our list of Value* is updated
70 /// properly through those transitions. This ensures that the
71 /// correct Value* is in our list when it comes time to associate
72 /// constants with global variables at the end of reading the
74 /// @brief A list of values as a User of those Values.
75 struct ValueList : public User {
76 ValueList() : User(Type::VoidTy, Value::ValueListVal) {}
78 // vector compatibility methods
79 unsigned size() const { return getNumOperands(); }
80 void push_back(Value *V) { Operands.push_back(Use(V, this)); }
81 Value *back() const { return Operands.back(); }
82 void pop_back() { Operands.pop_back(); }
83 bool empty() const { return Operands.empty(); }
85 virtual void print(std::ostream& os) const {
86 for ( unsigned i = 0; i < size(); i++ ) {
88 getOperand(i)->print(os);
94 /// @brief A 2 dimensional table of values
95 typedef std::vector<ValueList*> ValueTable;
97 /// This map is needed so that forward references to constants can be looked
98 /// up by Type and slot number when resolving those references.
99 /// @brief A mapping of a Type/slot pair to a Constant*.
100 typedef std::map<std::pair<const Type*,unsigned>, Constant*> ConstantRefsType;
102 /// For lazy read-in of functions, we need to save the location in the
103 /// data stream where the function is located. This structure provides that
104 /// information. Lazy read-in is used mostly by the JIT which only wants to
105 /// resolve functions as it needs them.
106 /// @brief Keeps pointers to function contents for later use.
107 struct LazyFunctionInfo {
108 const unsigned char *Buf, *EndBuf;
109 LazyFunctionInfo(const unsigned char *B = 0, const unsigned char *EB = 0)
110 : Buf(B), EndBuf(EB) {}
113 /// @brief A mapping of functions to their LazyFunctionInfo for lazy reading.
114 typedef std::map<Function*, LazyFunctionInfo> LazyFunctionMap;
116 /// @brief A list of global variables and the slot number that initializes
118 typedef std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInitsList;
120 /// This type maps a typeslot/valueslot pair to the corresponding Value*.
121 /// It is used for dealing with forward references as values are read in.
122 /// @brief A map for dealing with forward references of values.
123 typedef std::map<std::pair<unsigned,unsigned>,Value*> ForwardReferenceMap;
129 /// @brief Main interface to parsing a bytecode buffer.
131 const unsigned char *Buf, ///< Beginning of the bytecode buffer
132 unsigned Length, ///< Length of the bytecode buffer
133 const std::string &ModuleID, ///< An identifier for the module constructed.
134 bool processFunctions=false ///< Process all function bodies fully.
137 /// @brief Parse all function bodies
138 void ParseAllFunctionBodies();
140 /// @brief Parse the next function of specific type
141 void ParseFunction(Function* Func) ;
143 /// This method is abstract in the parent ModuleProvider class. Its
144 /// implementation is identical to the ParseFunction method.
145 /// @see ParseFunction
146 /// @brief Make a specific function materialize.
147 virtual void materializeFunction(Function *F) {
148 LazyFunctionMap::iterator Fi = LazyFunctionLoadMap.find(F);
149 if (Fi == LazyFunctionLoadMap.end()) return;
153 /// This method is abstract in the parent ModuleProvider class. Its
154 /// implementation is identical to ParseAllFunctionBodies.
155 /// @see ParseAllFunctionBodies
156 /// @brief Make the whole module materialize
157 virtual Module* materializeModule() {
158 ParseAllFunctionBodies();
162 /// This method is provided by the parent ModuleProvde class and overriden
163 /// here. It simply releases the module from its provided and frees up our
165 /// @brief Release our hold on the generated module
166 Module* releaseModule() {
167 // Since we're losing control of this Module, we must hand it back complete
168 Module *M = ModuleProvider::releaseModule();
174 /// @name Parsing Units For Subclasses
177 /// @brief Parse whole module scope
180 /// @brief Parse the version information block
181 void ParseVersionInfo();
183 /// @brief Parse the ModuleGlobalInfo block
184 void ParseModuleGlobalInfo();
186 /// @brief Parse a symbol table
187 void ParseSymbolTable( Function* Func, SymbolTable *ST);
189 /// @brief Parse functions lazily.
190 void ParseFunctionLazily();
192 /// @brief Parse a function body
193 void ParseFunctionBody(Function* Func);
195 /// @brief Parse the type list portion of a compaction table
196 void BytecodeReader::ParseCompactionTypes( unsigned NumEntries );
198 /// @brief Parse a compaction table
199 void ParseCompactionTable();
201 /// @brief Parse global types
202 void ParseGlobalTypes();
204 /// @brief Parse a basic block (for LLVM 1.0 basic block blocks)
205 BasicBlock* ParseBasicBlock(unsigned BlockNo);
207 /// @brief parse an instruction list (for post LLVM 1.0 instruction lists
208 /// with blocks differentiated by terminating instructions.
209 unsigned ParseInstructionList(
210 Function* F ///< The function into which BBs will be inserted
213 /// @brief Parse a single instruction.
214 void ParseInstruction(
215 std::vector<unsigned>& Args, ///< The arguments to be filled in
216 BasicBlock* BB ///< The BB the instruction goes in
219 /// @brief Parse the whole constant pool
220 void ParseConstantPool(ValueTable& Values, TypeListTy& Types,
223 /// @brief Parse a single constant value
224 Constant* ParseConstantValue(unsigned TypeID);
226 /// @brief Parse a block of types constants
227 void ParseTypes(TypeListTy &Tab, unsigned NumEntries);
229 /// @brief Parse a single type constant
230 const Type *ParseType();
232 /// @brief Parse a string constants block
233 void ParseStringConstants(unsigned NumEntries, ValueTable &Tab);
239 BufPtr MemStart; ///< Start of the memory buffer
240 BufPtr MemEnd; ///< End of the memory buffer
241 BufPtr BlockStart; ///< Start of current block being parsed
242 BufPtr BlockEnd; ///< End of current block being parsed
243 BufPtr At; ///< Where we're currently parsing at
245 /// Information about the module, extracted from the bytecode revision number.
246 unsigned char RevisionNum; // The rev # itself
248 /// Flags to distinguish LLVM 1.0 & 1.1 bytecode formats (revision #0)
250 /// Revision #0 had an explicit alignment of data only for the ModuleGlobalInfo
251 /// block. This was fixed to be like all other blocks in 1.2
252 bool hasInconsistentModuleGlobalInfo;
254 /// Revision #0 also explicitly encoded zero values for primitive types like
256 bool hasExplicitPrimitiveZeros;
258 // Flags to control features specific the LLVM 1.2 and before (revision #1)
260 /// LLVM 1.2 and earlier required that getelementptr structure indices were
261 /// ubyte constants and that sequential type indices were longs.
262 bool hasRestrictedGEPTypes;
264 /// LLVM 1.2 and earlier had class Type deriving from Value and the Type
265 /// objects were located in the "Type Type" plane of various lists in read
266 /// by the bytecode reader. In LLVM 1.3 this is no longer the case. Types are
267 /// completely distinct from Values. Consequently, Types are written in fixed
268 /// locations in LLVM 1.3. This flag indicates that the older Type derived
269 /// from Value style of bytecode file is being read.
270 bool hasTypeDerivedFromValue;
272 /// LLVM 1.2 and earlier encoded block headers as two uint (8 bytes), one for
273 /// the size and one for the type. This is a bit wasteful, especially for small
274 /// files where the 8 bytes per block is a large fraction of the total block
275 /// size. In LLVM 1.3, the block type and length are encoded into a single
276 /// uint32 by restricting the number of block types (limit 31) and the maximum
277 /// size of a block (limit 2^27-1=134,217,727). Note that the module block
278 /// still uses the 8-byte format so the maximum size of a file can be
279 /// 2^32-1 bytes long.
280 bool hasLongBlockHeaders;
282 /// LLVM 1.2 and earlier wrote type slot numbers as vbr_uint32. In LLVM 1.3
283 /// this has been reduced to vbr_uint24. It shouldn't make much difference
284 /// since we haven't run into a module with > 24 million types, but for safety
285 /// the 24-bit restriction has been enforced in 1.3 to free some bits in
286 /// various places and to ensure consistency. In particular, global vars are
287 /// restricted to 24-bits.
290 /// LLVM 1.2 and earlier did not provide a target triple nor a list of
291 /// libraries on which the bytecode is dependent. LLVM 1.3 provides these
292 /// features, for use in future versions of LLVM.
293 bool hasNoDependentLibraries;
295 /// LLVM 1.2 and earlier encoded the file version as part of the module block
296 /// but this information may be needed to
298 /// CompactionTable - If a compaction table is active in the current function,
299 /// this is the mapping that it contains.
300 std::vector<const Type*> CompactionTypes;
302 /// @brief If a compaction table is active in the current function,
303 /// this is the mapping that it contains.
304 std::vector<std::vector<Value*> > CompactionValues;
306 /// @brief This vector is used to deal with forward references to types in
308 TypeListTy ModuleTypes;
310 /// @brief This vector is used to deal with forward references to types in
312 TypeListTy FunctionTypes;
314 /// When the ModuleGlobalInfo section is read, we create a Function object
315 /// for each function in the module. When the function is loaded, after the
316 /// module global info is read, this Function is populated. Until then, the
317 /// functions in this vector just hold the function signature.
318 std::vector<Function*> FunctionSignatureList;
320 /// @brief This is the table of values belonging to the current function
321 ValueTable FunctionValues;
323 /// @brief This is the table of values belonging to the module (global)
324 ValueTable ModuleValues;
326 /// @brief This keeps track of function level forward references.
327 ForwardReferenceMap ForwardReferences;
329 /// @brief The basic blocks we've parsed, while parsing a function.
330 std::vector<BasicBlock*> ParsedBasicBlocks;
332 /// This maintains a mapping between <Type, Slot #>'s and
333 /// forward references to constants. Such values may be referenced before they
334 /// are defined, and if so, the temporary object that they represent is held
336 /// @brief Temporary place for forward references to constants.
337 ConstantRefsType ConstantFwdRefs;
339 /// Constant values are read in after global variables. Because of this, we
340 /// must defer setting the initializers on global variables until after module
341 /// level constants have been read. In the mean time, this list keeps track of
343 GlobalInitsList GlobalInits;
345 // For lazy reading-in of functions, we need to save away several pieces of
346 // information about each function: its begin and end pointer in the buffer
347 // and its FunctionSlot.
348 LazyFunctionMap LazyFunctionLoadMap;
350 /// This stores the parser's handler which is used for handling tasks other
351 /// just than reading bytecode into the IR. If this is non-null, calls on
352 /// the (polymorphic) BytecodeHandler interface (see llvm/Bytecode/Handler.h)
353 /// will be made to report the logical structure of the bytecode file. What
354 /// the handler does with the events it receives is completely orthogonal to
355 /// the business of parsing the bytecode and building the IR. This is used,
356 /// for example, by the llvm-abcd tool for analysis of byte code.
357 /// @brief Handler for parsing events.
358 BytecodeHandler* Handler;
361 /// @name Implementation Details
364 /// @brief Determines if this module has a function or not.
365 bool hasFunctions() { return ! FunctionSignatureList.empty(); }
367 /// @brief Determines if the type id has an implicit null value.
368 bool hasImplicitNull(unsigned TyID );
370 /// @brief Converts a type slot number to its Type*
371 const Type *getType(unsigned ID);
373 /// @brief Converts a pre-sanitized type slot number to its Type* and
374 /// sanitizes the type id.
375 inline const Type* getSanitizedType(unsigned& ID );
377 /// @brief Read in and get a sanitized type id
378 inline const Type* BytecodeReader::readSanitizedType();
380 /// @brief Converts a Type* to its type slot number
381 unsigned getTypeSlot(const Type *Ty);
383 /// @brief Converts a normal type slot number to a compacted type slot num.
384 unsigned getCompactionTypeSlot(unsigned type);
386 /// @brief Gets the global type corresponding to the TypeId
387 const Type *getGlobalTableType(unsigned TypeId);
389 /// This is just like getTypeSlot, but when a compaction table is in use,
391 unsigned getGlobalTableTypeSlot(const Type *Ty);
393 /// @brief Get a value from its typeid and slot number
394 Value* getValue(unsigned TypeID, unsigned num, bool Create = true);
396 /// @brief Get a value from its type and slot number, ignoring compaction tables.
397 Value *getGlobalTableValue(const Type *Ty, unsigned SlotNo);
399 /// @brief Get a basic block for current function
400 BasicBlock *getBasicBlock(unsigned ID);
402 /// @brief Get a constant value from its typeid and value slot.
403 Constant* getConstantValue(unsigned typeSlot, unsigned valSlot);
405 /// @brief Convenience function for getting a constant value when
406 /// the Type has already been resolved.
407 Constant* getConstantValue(const Type *Ty, unsigned valSlot) {
408 return getConstantValue(getTypeSlot(Ty), valSlot);
411 /// @brief Insert a newly created value
412 unsigned insertValue(Value *V, unsigned Type, ValueTable &Table);
414 /// @brief Insert the arguments of a function.
415 void insertArguments(Function* F );
417 /// @brief Resolve all references to the placeholder (if any) for the
419 void ResolveReferencesToConstant(Constant *C, unsigned Slot);
421 /// @brief Release our memory.
423 freeTable(FunctionValues);
424 freeTable(ModuleValues);
427 /// @brief Free a table, making sure to free the ValueList in the table.
428 void freeTable(ValueTable &Tab) {
429 while (!Tab.empty()) {
435 inline void error(std::string errmsg);
437 BytecodeReader(const BytecodeReader &); // DO NOT IMPLEMENT
438 void operator=(const BytecodeReader &); // DO NOT IMPLEMENT
441 /// @name Reader Primitives
445 /// @brief Is there more to parse in the current block?
446 inline bool moreInBlock();
448 /// @brief Have we read past the end of the block
449 inline void checkPastBlockEnd(const char * block_name);
451 /// @brief Align to 32 bits
452 inline void align32();
454 /// @brief Read an unsigned integer as 32-bits
455 inline unsigned read_uint();
457 /// @brief Read an unsigned integer with variable bit rate encoding
458 inline unsigned read_vbr_uint();
460 /// @brief Read an unsigned integer of no more than 24-bits with variable
461 /// bit rate encoding.
462 inline unsigned read_vbr_uint24();
464 /// @brief Read an unsigned 64-bit integer with variable bit rate encoding.
465 inline uint64_t read_vbr_uint64();
467 /// @brief Read a signed 64-bit integer with variable bit rate encoding.
468 inline int64_t read_vbr_int64();
470 /// @brief Read a string
471 inline std::string read_str();
473 /// @brief Read a float value
474 inline void read_float(float& FloatVal);
476 /// @brief Read a double value
477 inline void read_double(double& DoubleVal);
479 /// @brief Read an arbitrary data chunk of fixed length
480 inline void read_data(void *Ptr, void *End);
482 /// @brief Read a bytecode block header
483 inline void read_block(unsigned &Type, unsigned &Size);
485 /// @brief Read a type identifier and sanitize it.
486 inline bool read_typeid(unsigned &TypeId);
488 /// @brief Recalculate type ID for pre 1.3 bytecode files.
489 inline bool sanitizeTypeId(unsigned &TypeId );
493 /// @brief A function for creating a BytecodeAnalzer as a handler
494 /// for the Bytecode reader.
495 BytecodeHandler* createBytecodeAnalyzerHandler(BytecodeAnalysis& bca );
498 } // End llvm namespace