BitcodeReader.h revision c2074caf075818abb6d3689ad924ca09f4a5ba1f 
1//===- BitcodeReader.h - Internal BitcodeReader impl ------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This header defines the BitcodeReader class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef BITCODE_READER_H
15#define BITCODE_READER_H
16
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/ADT/OwningPtr.h"
19#include "llvm/Bitcode/BitstreamReader.h"
20#include "llvm/Bitcode/LLVMBitCodes.h"
21#include "llvm/IR/Attributes.h"
22#include "llvm/IR/GVMaterializer.h"
23#include "llvm/IR/OperandTraits.h"
24#include "llvm/IR/Type.h"
25#include "llvm/IR/ValueHandle.h"
26#include <vector>
27
28namespace llvm {
29  class MemoryBuffer;
30  class LLVMContext;
31}
32
33namespace llvm_3_0 {
34
35using namespace llvm;
36
37//===----------------------------------------------------------------------===//
38//                          BitcodeReaderValueList Class
39//===----------------------------------------------------------------------===//
40
41class BitcodeReaderValueList {
42  std::vector<WeakVH> ValuePtrs;
43
44  /// ResolveConstants - As we resolve forward-referenced constants, we add
45  /// information about them to this vector.  This allows us to resolve them in
46  /// bulk instead of resolving each reference at a time.  See the code in
47  /// ResolveConstantForwardRefs for more information about this.
48  ///
49  /// The key of this vector is the placeholder constant, the value is the slot
50  /// number that holds the resolved value.
51  typedef std::vector<std::pair<Constant*, unsigned> > ResolveConstantsTy;
52  ResolveConstantsTy ResolveConstants;
53  LLVMContext &Context;
54public:
55  BitcodeReaderValueList(LLVMContext &C) : Context(C) {}
56  ~BitcodeReaderValueList() {
57    assert(ResolveConstants.empty() && "Constants not resolved?");
58  }
59
60  // vector compatibility methods
61  unsigned size() const { return ValuePtrs.size(); }
62  void resize(unsigned N) { ValuePtrs.resize(N); }
63  void push_back(Value *V) {
64    ValuePtrs.push_back(V);
65  }
66
67  void clear() {
68    assert(ResolveConstants.empty() && "Constants not resolved?");
69    ValuePtrs.clear();
70  }
71
72  Value *operator[](unsigned i) const {
73    assert(i < ValuePtrs.size());
74    return ValuePtrs[i];
75  }
76
77  Value *back() const { return ValuePtrs.back(); }
78    void pop_back() { ValuePtrs.pop_back(); }
79  bool empty() const { return ValuePtrs.empty(); }
80  void shrinkTo(unsigned N) {
81    assert(N <= size() && "Invalid shrinkTo request!");
82    ValuePtrs.resize(N);
83  }
84
85  Constant *getConstantFwdRef(unsigned Idx, Type *Ty);
86  Value *getValueFwdRef(unsigned Idx, Type *Ty);
87
88  void AssignValue(Value *V, unsigned Idx);
89
90  /// ResolveConstantForwardRefs - Once all constants are read, this method bulk
91  /// resolves any forward references.
92  void ResolveConstantForwardRefs();
93};
94
95
96//===----------------------------------------------------------------------===//
97//                          BitcodeReaderMDValueList Class
98//===----------------------------------------------------------------------===//
99
100class BitcodeReaderMDValueList {
101  std::vector<WeakVH> MDValuePtrs;
102
103  LLVMContext &Context;
104public:
105  BitcodeReaderMDValueList(LLVMContext& C) : Context(C) {}
106
107  // vector compatibility methods
108  unsigned size() const       { return MDValuePtrs.size(); }
109  void resize(unsigned N)     { MDValuePtrs.resize(N); }
110  void push_back(Value *V)    { MDValuePtrs.push_back(V);  }
111  void clear()                { MDValuePtrs.clear();  }
112  Value *back() const         { return MDValuePtrs.back(); }
113  void pop_back()             { MDValuePtrs.pop_back(); }
114  bool empty() const          { return MDValuePtrs.empty(); }
115
116  Value *operator[](unsigned i) const {
117    assert(i < MDValuePtrs.size());
118    return MDValuePtrs[i];
119  }
120
121  void shrinkTo(unsigned N) {
122    assert(N <= size() && "Invalid shrinkTo request!");
123    MDValuePtrs.resize(N);
124  }
125
126  Value *getValueFwdRef(unsigned Idx);
127  void AssignValue(Value *V, unsigned Idx);
128};
129
130class BitcodeReader : public GVMaterializer {
131  LLVMContext &Context;
132  Module *TheModule;
133  MemoryBuffer *Buffer;
134  bool BufferOwned;
135  OwningPtr<BitstreamReader> StreamFile;
136  BitstreamCursor Stream;
137  DataStreamer *LazyStreamer;
138  uint64_t NextUnreadBit;
139  bool SeenValueSymbolTable;
140
141  std::vector<Type*> TypeList;
142  BitcodeReaderValueList ValueList;
143  BitcodeReaderMDValueList MDValueList;
144  SmallVector<Instruction *, 64> InstructionList;
145
146  std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInits;
147  std::vector<std::pair<GlobalAlias*, unsigned> > AliasInits;
148
149  /// MAttributes - The set of attributes by index.  Index zero in the
150  /// file is for null, and is thus not represented here.  As such all indices
151  /// are off by one.
152  std::vector<AttributeSet> MAttributes;
153
154  /// \brief The set of attribute groups.
155  std::map<unsigned, AttributeSet> MAttributeGroups;
156
157  /// FunctionBBs - While parsing a function body, this is a list of the basic
158  /// blocks for the function.
159  std::vector<BasicBlock*> FunctionBBs;
160
161  // When reading the module header, this list is populated with functions that
162  // have bodies later in the file.
163  std::vector<Function*> FunctionsWithBodies;
164
165  // When intrinsic functions are encountered which require upgrading they are
166  // stored here with their replacement function.
167  typedef std::vector<std::pair<Function*, Function*> > UpgradedIntrinsicMap;
168  UpgradedIntrinsicMap UpgradedIntrinsics;
169
170  // Map the bitcode's custom MDKind ID to the Module's MDKind ID.
171  DenseMap<unsigned, unsigned> MDKindMap;
172
173  // Several operations happen after the module header has been read, but
174  // before function bodies are processed. This keeps track of whether
175  // we've done this yet.
176  bool SeenFirstFunctionBody;
177
178  /// DeferredFunctionInfo - When function bodies are initially scanned, this
179  /// map contains info about where to find deferred function body in the
180  /// stream.
181  DenseMap<Function*, uint64_t> DeferredFunctionInfo;
182
183  /// BlockAddrFwdRefs - These are blockaddr references to basic blocks.  These
184  /// are resolved lazily when functions are loaded.
185  typedef std::pair<unsigned, GlobalVariable*> BlockAddrRefTy;
186  DenseMap<Function*, std::vector<BlockAddrRefTy> > BlockAddrFwdRefs;
187
188  static const error_category &BitcodeErrorCategory();
189
190public:
191  enum ErrorType {
192    BitcodeStreamInvalidSize,
193    ConflictingMETADATA_KINDRecords,
194    CouldNotFindFunctionInStream,
195    ExpectedConstant,
196    InsufficientFunctionProtos,
197    InvalidBitcodeSignature,
198    InvalidBitcodeWrapperHeader,
199    InvalidConstantReference,
200    InvalidID, // A read identifier is not found in the table it should be in.
201    InvalidInstructionWithNoBB,
202    InvalidRecord, // A read record doesn't have the expected size or structure
203    InvalidTypeForValue, // Type read OK, but is invalid for its use
204    InvalidTYPETable,
205    InvalidType, // We were unable to read a type
206    MalformedBlock, // We are unable to advance in the stream.
207    MalformedGlobalInitializerSet,
208    InvalidMultipleBlocks, // We found multiple blocks of a kind that should
209                           // have only one
210    NeverResolvedValueFoundInFunction,
211    InvalidValue // Invalid version, inst number, attr number, etc
212  };
213
214  error_code Error(ErrorType E) {
215    return error_code(E, BitcodeErrorCategory());
216  }
217
218  explicit BitcodeReader(MemoryBuffer *buffer, LLVMContext &C)
219    : Context(C), TheModule(0), Buffer(buffer), BufferOwned(false),
220      LazyStreamer(0), NextUnreadBit(0), SeenValueSymbolTable(false),
221      ValueList(C), MDValueList(C),
222      SeenFirstFunctionBody(false) {
223  }
224  ~BitcodeReader() {
225    FreeState();
226  }
227
228  void FreeState();
229
230  /// setBufferOwned - If this is true, the reader will destroy the MemoryBuffer
231  /// when the reader is destroyed.
232  void setBufferOwned(bool Owned) { BufferOwned = Owned; }
233
234  virtual bool isMaterializable(const GlobalValue *GV) const;
235  virtual bool isDematerializable(const GlobalValue *GV) const;
236  virtual error_code Materialize(GlobalValue *GV);
237  virtual error_code MaterializeModule(Module *M);
238  virtual void Dematerialize(GlobalValue *GV);
239
240  /// @brief Main interface to parsing a bitcode buffer.
241  /// @returns true if an error occurred.
242  error_code ParseBitcodeInto(Module *M);
243
244  /// @brief Cheap mechanism to just extract module triple
245  /// @returns true if an error occurred.
246  error_code ParseTriple(std::string &Triple);
247
248  static uint64_t decodeSignRotatedValue(uint64_t V);
249
250private:
251  Type *getTypeByID(unsigned ID);
252  Type *getTypeByIDOrNull(unsigned ID);
253  Value *getFnValueByID(unsigned ID, Type *Ty) {
254    if (Ty && Ty->isMetadataTy())
255      return MDValueList.getValueFwdRef(ID);
256    return ValueList.getValueFwdRef(ID, Ty);
257  }
258  BasicBlock *getBasicBlock(unsigned ID) const {
259    if (ID >= FunctionBBs.size()) return 0; // Invalid ID
260    return FunctionBBs[ID];
261  }
262  AttributeSet getAttributes(unsigned i) const {
263    if (i-1 < MAttributes.size())
264      return MAttributes[i-1];
265    return AttributeSet();
266  }
267
268  /// getValueTypePair - Read a value/type pair out of the specified record from
269  /// slot 'Slot'.  Increment Slot past the number of slots used in the record.
270  /// Return true on failure.
271  bool getValueTypePair(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
272                        unsigned InstNum, Value *&ResVal) {
273    if (Slot == Record.size()) return true;
274    unsigned ValNo = (unsigned)Record[Slot++];
275    if (ValNo < InstNum) {
276      // If this is not a forward reference, just return the value we already
277      // have.
278      ResVal = getFnValueByID(ValNo, 0);
279      return ResVal == 0;
280    } else if (Slot == Record.size()) {
281      return true;
282    }
283
284    unsigned TypeNo = (unsigned)Record[Slot++];
285    ResVal = getFnValueByID(ValNo, getTypeByID(TypeNo));
286    return ResVal == 0;
287  }
288  bool getValue(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
289                Type *Ty, Value *&ResVal) {
290    if (Slot == Record.size()) return true;
291    unsigned ValNo = (unsigned)Record[Slot++];
292    ResVal = getFnValueByID(ValNo, Ty);
293    return ResVal == 0;
294  }
295
296
297  error_code ParseModule(bool Resume);
298  error_code ParseAttributeBlock();
299  error_code ParseTypeTable();
300  error_code ParseOldTypeTable();         // FIXME: Remove in LLVM 3.1
301  error_code ParseTypeTableBody();
302
303  error_code ParseOldTypeSymbolTable();   // FIXME: Remove in LLVM 3.1
304  error_code ParseValueSymbolTable();
305  error_code ParseConstants();
306  error_code RememberAndSkipFunctionBody();
307  error_code ParseFunctionBody(Function *F);
308  error_code GlobalCleanup();
309  error_code ResolveGlobalAndAliasInits();
310  error_code ParseMetadata();
311  error_code ParseMetadataAttachment();
312  error_code ParseModuleTriple(std::string &Triple);
313  error_code InitStream();
314  error_code InitStreamFromBuffer();
315  error_code InitLazyStream();
316};
317
318} // End llvm_3_0 namespace
319
320#endif
321