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/Bitcode/BitstreamReader.h"
19#include "llvm/Bitcode/LLVMBitCodes.h"
20#include "llvm/IR/Attributes.h"
21#include "llvm/IR/GVMaterializer.h"
22#include "llvm/IR/OperandTraits.h"
23#include "llvm/IR/Type.h"
24#include "llvm/IR/ValueHandle.h"
25#include <vector>
26
27namespace llvm {
28  class MemoryBuffer;
29  class LLVMContext;
30}
31
32namespace llvm_3_0 {
33
34using namespace llvm;
35
36//===----------------------------------------------------------------------===//
37//                          BitcodeReaderValueList Class
38//===----------------------------------------------------------------------===//
39
40class BitcodeReaderValueList {
41  std::vector<WeakVH> ValuePtrs;
42
43  /// ResolveConstants - As we resolve forward-referenced constants, we add
44  /// information about them to this vector.  This allows us to resolve them in
45  /// bulk instead of resolving each reference at a time.  See the code in
46  /// ResolveConstantForwardRefs for more information about this.
47  ///
48  /// The key of this vector is the placeholder constant, the value is the slot
49  /// number that holds the resolved value.
50  typedef std::vector<std::pair<Constant*, unsigned> > ResolveConstantsTy;
51  ResolveConstantsTy ResolveConstants;
52  LLVMContext &Context;
53public:
54  BitcodeReaderValueList(LLVMContext &C) : Context(C) {}
55  ~BitcodeReaderValueList() {
56    assert(ResolveConstants.empty() && "Constants not resolved?");
57  }
58
59  // vector compatibility methods
60  unsigned size() const { return ValuePtrs.size(); }
61  void resize(unsigned N) { ValuePtrs.resize(N); }
62  void push_back(Value *V) {
63    ValuePtrs.push_back(V);
64  }
65
66  void clear() {
67    assert(ResolveConstants.empty() && "Constants not resolved?");
68    ValuePtrs.clear();
69  }
70
71  Value *operator[](unsigned i) const {
72    assert(i < ValuePtrs.size());
73    return ValuePtrs[i];
74  }
75
76  Value *back() const { return ValuePtrs.back(); }
77    void pop_back() { ValuePtrs.pop_back(); }
78  bool empty() const { return ValuePtrs.empty(); }
79  void shrinkTo(unsigned N) {
80    assert(N <= size() && "Invalid shrinkTo request!");
81    ValuePtrs.resize(N);
82  }
83
84  Constant *getConstantFwdRef(unsigned Idx, Type *Ty);
85  Value *getValueFwdRef(unsigned Idx, Type *Ty);
86
87  void AssignValue(Value *V, unsigned Idx);
88
89  /// ResolveConstantForwardRefs - Once all constants are read, this method bulk
90  /// resolves any forward references.
91  void ResolveConstantForwardRefs();
92};
93
94
95//===----------------------------------------------------------------------===//
96//                          BitcodeReaderMDValueList Class
97//===----------------------------------------------------------------------===//
98
99class BitcodeReaderMDValueList {
100  std::vector<WeakVH> MDValuePtrs;
101
102  LLVMContext &Context;
103public:
104  BitcodeReaderMDValueList(LLVMContext& C) : Context(C) {}
105
106  // vector compatibility methods
107  unsigned size() const       { return MDValuePtrs.size(); }
108  void resize(unsigned N)     { MDValuePtrs.resize(N); }
109  void push_back(Value *V)    { MDValuePtrs.push_back(V);  }
110  void clear()                { MDValuePtrs.clear();  }
111  Value *back() const         { return MDValuePtrs.back(); }
112  void pop_back()             { MDValuePtrs.pop_back(); }
113  bool empty() const          { return MDValuePtrs.empty(); }
114
115  Value *operator[](unsigned i) const {
116    assert(i < MDValuePtrs.size());
117    return MDValuePtrs[i];
118  }
119
120  void shrinkTo(unsigned N) {
121    assert(N <= size() && "Invalid shrinkTo request!");
122    MDValuePtrs.resize(N);
123  }
124
125  Value *getValueFwdRef(unsigned Idx);
126  void AssignValue(Value *V, unsigned Idx);
127};
128
129class BitcodeReader : public GVMaterializer {
130  LLVMContext &Context;
131  Module *TheModule;
132  MemoryBuffer *Buffer;
133  bool BufferOwned;
134  std::unique_ptr<BitstreamReader> StreamFile;
135  BitstreamCursor Stream;
136  DataStreamer *LazyStreamer;
137  uint64_t NextUnreadBit;
138  bool SeenValueSymbolTable;
139
140  std::vector<Type*> TypeList;
141  BitcodeReaderValueList ValueList;
142  BitcodeReaderMDValueList MDValueList;
143  SmallVector<Instruction *, 64> InstructionList;
144
145  std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInits;
146  std::vector<std::pair<GlobalAlias*, unsigned> > AliasInits;
147
148  /// MAttributes - The set of attributes by index.  Index zero in the
149  /// file is for null, and is thus not represented here.  As such all indices
150  /// are off by one.
151  std::vector<AttributeSet> MAttributes;
152
153  /// \brief The set of attribute groups.
154  std::map<unsigned, AttributeSet> MAttributeGroups;
155
156  /// FunctionBBs - While parsing a function body, this is a list of the basic
157  /// blocks for the function.
158  std::vector<BasicBlock*> FunctionBBs;
159
160  // When reading the module header, this list is populated with functions that
161  // have bodies later in the file.
162  std::vector<Function*> FunctionsWithBodies;
163
164  // When intrinsic functions are encountered which require upgrading they are
165  // stored here with their replacement function.
166  typedef std::vector<std::pair<Function*, Function*> > UpgradedIntrinsicMap;
167  UpgradedIntrinsicMap UpgradedIntrinsics;
168
169  // Map the bitcode's custom MDKind ID to the Module's MDKind ID.
170  DenseMap<unsigned, unsigned> MDKindMap;
171
172  // Several operations happen after the module header has been read, but
173  // before function bodies are processed. This keeps track of whether
174  // we've done this yet.
175  bool SeenFirstFunctionBody;
176
177  /// DeferredFunctionInfo - When function bodies are initially scanned, this
178  /// map contains info about where to find deferred function body in the
179  /// stream.
180  DenseMap<Function*, uint64_t> DeferredFunctionInfo;
181
182  /// BlockAddrFwdRefs - These are blockaddr references to basic blocks.  These
183  /// are resolved lazily when functions are loaded.
184  typedef std::pair<unsigned, GlobalVariable*> BlockAddrRefTy;
185  DenseMap<Function*, std::vector<BlockAddrRefTy> > BlockAddrFwdRefs;
186
187  static const std::error_category &BitcodeErrorCategory();
188
189public:
190  enum ErrorType {
191    BitcodeStreamInvalidSize,
192    ConflictingMETADATA_KINDRecords,
193    CouldNotFindFunctionInStream,
194    ExpectedConstant,
195    InsufficientFunctionProtos,
196    InvalidBitcodeSignature,
197    InvalidBitcodeWrapperHeader,
198    InvalidConstantReference,
199    InvalidID, // A read identifier is not found in the table it should be in.
200    InvalidInstructionWithNoBB,
201    InvalidRecord, // A read record doesn't have the expected size or structure
202    InvalidTypeForValue, // Type read OK, but is invalid for its use
203    InvalidTYPETable,
204    InvalidType, // We were unable to read a type
205    MalformedBlock, // We are unable to advance in the stream.
206    MalformedGlobalInitializerSet,
207    InvalidMultipleBlocks, // We found multiple blocks of a kind that should
208                           // have only one
209    NeverResolvedValueFoundInFunction,
210    InvalidValue // Invalid version, inst number, attr number, etc
211  };
212
213  std::error_code Error(ErrorType E) {
214    return std::error_code(E, BitcodeErrorCategory());
215  }
216
217  explicit BitcodeReader(MemoryBuffer *buffer, LLVMContext &C)
218    : Context(C), TheModule(0), Buffer(buffer), BufferOwned(false),
219      LazyStreamer(0), NextUnreadBit(0), SeenValueSymbolTable(false),
220      ValueList(C), MDValueList(C),
221      SeenFirstFunctionBody(false) {
222  }
223  ~BitcodeReader() {
224    FreeState();
225  }
226
227  void FreeState();
228
229  /// setBufferOwned - If this is true, the reader will destroy the MemoryBuffer
230  /// when the reader is destroyed.
231  void setBufferOwned(bool Owned) { BufferOwned = Owned; }
232
233  void releaseBuffer() {
234    Buffer = nullptr;
235  }
236
237  virtual bool isMaterializable(const GlobalValue *GV) const;
238  virtual bool isDematerializable(const GlobalValue *GV) const;
239  virtual std::error_code Materialize(GlobalValue *GV);
240  virtual std::error_code MaterializeModule(Module *M);
241  virtual void Dematerialize(GlobalValue *GV);
242
243  /// @brief Main interface to parsing a bitcode buffer.
244  /// @returns true if an error occurred.
245  std::error_code ParseBitcodeInto(Module *M);
246
247  /// @brief Cheap mechanism to just extract module triple
248  /// @returns true if an error occurred.
249  std::error_code ParseTriple(std::string &Triple);
250
251  static uint64_t decodeSignRotatedValue(uint64_t V);
252
253private:
254  Type *getTypeByID(unsigned ID);
255  Type *getTypeByIDOrNull(unsigned ID);
256  Value *getFnValueByID(unsigned ID, Type *Ty) {
257    if (Ty && Ty->isMetadataTy())
258      return MDValueList.getValueFwdRef(ID);
259    return ValueList.getValueFwdRef(ID, Ty);
260  }
261  BasicBlock *getBasicBlock(unsigned ID) const {
262    if (ID >= FunctionBBs.size()) return 0; // Invalid ID
263    return FunctionBBs[ID];
264  }
265  AttributeSet getAttributes(unsigned i) const {
266    if (i-1 < MAttributes.size())
267      return MAttributes[i-1];
268    return AttributeSet();
269  }
270
271  /// getValueTypePair - Read a value/type pair out of the specified record from
272  /// slot 'Slot'.  Increment Slot past the number of slots used in the record.
273  /// Return true on failure.
274  bool getValueTypePair(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
275                        unsigned InstNum, Value *&ResVal) {
276    if (Slot == Record.size()) return true;
277    unsigned ValNo = (unsigned)Record[Slot++];
278    if (ValNo < InstNum) {
279      // If this is not a forward reference, just return the value we already
280      // have.
281      ResVal = getFnValueByID(ValNo, 0);
282      return ResVal == 0;
283    } else if (Slot == Record.size()) {
284      return true;
285    }
286
287    unsigned TypeNo = (unsigned)Record[Slot++];
288    ResVal = getFnValueByID(ValNo, getTypeByID(TypeNo));
289    return ResVal == 0;
290  }
291  bool getValue(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
292                Type *Ty, Value *&ResVal) {
293    if (Slot == Record.size()) return true;
294    unsigned ValNo = (unsigned)Record[Slot++];
295    ResVal = getFnValueByID(ValNo, Ty);
296    return ResVal == 0;
297  }
298
299
300  std::error_code ParseModule(bool Resume);
301  std::error_code ParseAttributeBlock();
302  std::error_code ParseTypeTable();
303  std::error_code ParseOldTypeTable();         // FIXME: Remove in LLVM 3.1
304  std::error_code ParseTypeTableBody();
305
306  std::error_code ParseOldTypeSymbolTable();   // FIXME: Remove in LLVM 3.1
307  std::error_code ParseValueSymbolTable();
308  std::error_code ParseConstants();
309  std::error_code RememberAndSkipFunctionBody();
310  std::error_code ParseFunctionBody(Function *F);
311  std::error_code GlobalCleanup();
312  std::error_code ResolveGlobalAndAliasInits();
313  std::error_code ParseMetadata();
314  std::error_code ParseMetadataAttachment();
315  std::error_code ParseModuleTriple(std::string &Triple);
316  std::error_code InitStream();
317  std::error_code InitStreamFromBuffer();
318  std::error_code InitLazyStream();
319};
320
321} // End llvm_3_0 namespace
322
323#endif
324