1//===-- Bitcode/Writer/ValueEnumerator.h - Number values --------*- 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 class gives values and types Unique ID's.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_LIB_BITCODE_WRITER_VALUEENUMERATOR_H
15#define LLVM_LIB_BITCODE_WRITER_VALUEENUMERATOR_H
16
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/ADT/UniqueVector.h"
19#include "llvm/IR/Attributes.h"
20#include "llvm/IR/Metadata.h"
21#include "llvm/IR/Type.h"
22#include "llvm/IR/UseListOrder.h"
23#include <vector>
24
25namespace llvm {
26
27class Type;
28class Value;
29class Instruction;
30class BasicBlock;
31class Comdat;
32class Function;
33class Module;
34class Metadata;
35class LocalAsMetadata;
36class MDNode;
37class MDOperand;
38class NamedMDNode;
39class AttributeSet;
40class ValueSymbolTable;
41class MDSymbolTable;
42class raw_ostream;
43
44class ValueEnumerator {
45public:
46  typedef std::vector<Type*> TypeList;
47
48  // For each value, we remember its Value* and occurrence frequency.
49  typedef std::vector<std::pair<const Value*, unsigned> > ValueList;
50
51  UseListOrderStack UseListOrders;
52
53private:
54  typedef DenseMap<Type*, unsigned> TypeMapType;
55  TypeMapType TypeMap;
56  TypeList Types;
57
58  typedef DenseMap<const Value*, unsigned> ValueMapType;
59  ValueMapType ValueMap;
60  ValueList Values;
61
62  typedef UniqueVector<const Comdat *> ComdatSetType;
63  ComdatSetType Comdats;
64
65  std::vector<const Metadata *> MDs;
66  std::vector<const Metadata *> FunctionMDs;
67
68  /// Index of information about a piece of metadata.
69  struct MDIndex {
70    unsigned F = 0;  ///< The ID of the function for this metadata, if any.
71    unsigned ID = 0; ///< The implicit ID of this metadata in bitcode.
72
73    MDIndex() = default;
74    explicit MDIndex(unsigned F) : F(F) {}
75
76    /// Check if this has a function tag, and it's different from NewF.
77    bool hasDifferentFunction(unsigned NewF) const { return F && F != NewF; }
78
79    /// Fetch the MD this references out of the given metadata array.
80    const Metadata *get(ArrayRef<const Metadata *> MDs) const {
81      assert(ID && "Expected non-zero ID");
82      assert(ID <= MDs.size() && "Expected valid ID");
83      return MDs[ID - 1];
84    }
85  };
86
87  typedef DenseMap<const Metadata *, MDIndex> MetadataMapType;
88  MetadataMapType MetadataMap;
89
90  /// Range of metadata IDs, as a half-open range.
91  struct MDRange {
92    unsigned First = 0;
93    unsigned Last = 0;
94
95    /// Number of strings in the prefix of the metadata range.
96    unsigned NumStrings = 0;
97
98    MDRange() = default;
99    explicit MDRange(unsigned First) : First(First) {}
100  };
101  SmallDenseMap<unsigned, MDRange, 1> FunctionMDInfo;
102
103  bool ShouldPreserveUseListOrder;
104
105  typedef DenseMap<AttributeSet, unsigned> AttributeGroupMapType;
106  AttributeGroupMapType AttributeGroupMap;
107  std::vector<AttributeSet> AttributeGroups;
108
109  typedef DenseMap<AttributeSet, unsigned> AttributeMapType;
110  AttributeMapType AttributeMap;
111  std::vector<AttributeSet> Attribute;
112
113  /// GlobalBasicBlockIDs - This map memoizes the basic block ID's referenced by
114  /// the "getGlobalBasicBlockID" method.
115  mutable DenseMap<const BasicBlock*, unsigned> GlobalBasicBlockIDs;
116
117  typedef DenseMap<const Instruction*, unsigned> InstructionMapType;
118  InstructionMapType InstructionMap;
119  unsigned InstructionCount;
120
121  /// BasicBlocks - This contains all the basic blocks for the currently
122  /// incorporated function.  Their reverse mapping is stored in ValueMap.
123  std::vector<const BasicBlock*> BasicBlocks;
124
125  /// When a function is incorporated, this is the size of the Values list
126  /// before incorporation.
127  unsigned NumModuleValues;
128
129  /// When a function is incorporated, this is the size of the Metadatas list
130  /// before incorporation.
131  unsigned NumModuleMDs = 0;
132  unsigned NumMDStrings = 0;
133
134  unsigned FirstFuncConstantID;
135  unsigned FirstInstID;
136
137  ValueEnumerator(const ValueEnumerator &) = delete;
138  void operator=(const ValueEnumerator &) = delete;
139public:
140  ValueEnumerator(const Module &M, bool ShouldPreserveUseListOrder);
141
142  void dump() const;
143  void print(raw_ostream &OS, const ValueMapType &Map, const char *Name) const;
144  void print(raw_ostream &OS, const MetadataMapType &Map,
145             const char *Name) const;
146
147  unsigned getValueID(const Value *V) const;
148  unsigned getMetadataID(const Metadata *MD) const {
149    auto ID = getMetadataOrNullID(MD);
150    assert(ID != 0 && "Metadata not in slotcalculator!");
151    return ID - 1;
152  }
153  unsigned getMetadataOrNullID(const Metadata *MD) const {
154    return MetadataMap.lookup(MD).ID;
155  }
156  unsigned numMDs() const { return MDs.size(); }
157
158  bool shouldPreserveUseListOrder() const { return ShouldPreserveUseListOrder; }
159
160  unsigned getTypeID(Type *T) const {
161    TypeMapType::const_iterator I = TypeMap.find(T);
162    assert(I != TypeMap.end() && "Type not in ValueEnumerator!");
163    return I->second-1;
164  }
165
166  unsigned getInstructionID(const Instruction *I) const;
167  void setInstructionID(const Instruction *I);
168
169  unsigned getAttributeID(AttributeSet PAL) const {
170    if (PAL.isEmpty()) return 0;  // Null maps to zero.
171    AttributeMapType::const_iterator I = AttributeMap.find(PAL);
172    assert(I != AttributeMap.end() && "Attribute not in ValueEnumerator!");
173    return I->second;
174  }
175
176  unsigned getAttributeGroupID(AttributeSet PAL) const {
177    if (PAL.isEmpty()) return 0;  // Null maps to zero.
178    AttributeGroupMapType::const_iterator I = AttributeGroupMap.find(PAL);
179    assert(I != AttributeGroupMap.end() && "Attribute not in ValueEnumerator!");
180    return I->second;
181  }
182
183  /// getFunctionConstantRange - Return the range of values that corresponds to
184  /// function-local constants.
185  void getFunctionConstantRange(unsigned &Start, unsigned &End) const {
186    Start = FirstFuncConstantID;
187    End = FirstInstID;
188  }
189
190  const ValueList &getValues() const { return Values; }
191
192  /// Check whether the current block has any metadata to emit.
193  bool hasMDs() const { return NumModuleMDs < MDs.size(); }
194
195  /// Get the MDString metadata for this block.
196  ArrayRef<const Metadata *> getMDStrings() const {
197    return makeArrayRef(MDs).slice(NumModuleMDs, NumMDStrings);
198  }
199
200  /// Get the non-MDString metadata for this block.
201  ArrayRef<const Metadata *> getNonMDStrings() const {
202    return makeArrayRef(MDs).slice(NumModuleMDs).slice(NumMDStrings);
203  }
204
205  const TypeList &getTypes() const { return Types; }
206  const std::vector<const BasicBlock*> &getBasicBlocks() const {
207    return BasicBlocks;
208  }
209  const std::vector<AttributeSet> &getAttributes() const {
210    return Attribute;
211  }
212  const std::vector<AttributeSet> &getAttributeGroups() const {
213    return AttributeGroups;
214  }
215
216  const ComdatSetType &getComdats() const { return Comdats; }
217  unsigned getComdatID(const Comdat *C) const;
218
219  /// getGlobalBasicBlockID - This returns the function-specific ID for the
220  /// specified basic block.  This is relatively expensive information, so it
221  /// should only be used by rare constructs such as address-of-label.
222  unsigned getGlobalBasicBlockID(const BasicBlock *BB) const;
223
224  /// incorporateFunction/purgeFunction - If you'd like to deal with a function,
225  /// use these two methods to get its data into the ValueEnumerator!
226  ///
227  void incorporateFunction(const Function &F);
228  void purgeFunction();
229  uint64_t computeBitsRequiredForTypeIndicies() const;
230
231private:
232  void OptimizeConstants(unsigned CstStart, unsigned CstEnd);
233
234  /// Reorder the reachable metadata.
235  ///
236  /// This is not just an optimization, but is mandatory for emitting MDString
237  /// correctly.
238  void organizeMetadata();
239
240  /// Drop the function tag from the transitive operands of the given node.
241  void dropFunctionFromMetadata(MetadataMapType::value_type &FirstMD);
242
243  /// Incorporate the function metadata.
244  ///
245  /// This should be called before enumerating LocalAsMetadata for the
246  /// function.
247  void incorporateFunctionMetadata(const Function &F);
248
249  /// Enumerate a single instance of metadata with the given function tag.
250  ///
251  /// If \c MD has already been enumerated, check that \c F matches its
252  /// function tag.  If not, call \a dropFunctionFromMetadata().
253  ///
254  /// Otherwise, mark \c MD as visited.  Assign it an ID, or just return it if
255  /// it's an \a MDNode.
256  const MDNode *enumerateMetadataImpl(unsigned F, const Metadata *MD);
257
258  unsigned getMetadataFunctionID(const Function *F) const;
259
260  /// Enumerate reachable metadata in (almost) post-order.
261  ///
262  /// Enumerate all the metadata reachable from MD.  We want to minimize the
263  /// cost of reading bitcode records, and so the primary consideration is that
264  /// operands of uniqued nodes are resolved before the nodes are read.  This
265  /// avoids re-uniquing them on the context and factors away RAUW support.
266  ///
267  /// This algorithm guarantees that subgraphs of uniqued nodes are in
268  /// post-order.  Distinct subgraphs reachable only from a single uniqued node
269  /// will be in post-order.
270  ///
271  /// \note The relative order of a distinct and uniqued node is irrelevant.
272  /// \a organizeMetadata() will later partition distinct nodes ahead of
273  /// uniqued ones.
274  ///{
275  void EnumerateMetadata(const Function *F, const Metadata *MD);
276  void EnumerateMetadata(unsigned F, const Metadata *MD);
277  ///}
278
279  void EnumerateFunctionLocalMetadata(const Function &F,
280                                      const LocalAsMetadata *Local);
281  void EnumerateFunctionLocalMetadata(unsigned F, const LocalAsMetadata *Local);
282  void EnumerateNamedMDNode(const NamedMDNode *NMD);
283  void EnumerateValue(const Value *V);
284  void EnumerateType(Type *T);
285  void EnumerateOperandType(const Value *V);
286  void EnumerateAttributes(AttributeSet PAL);
287
288  void EnumerateValueSymbolTable(const ValueSymbolTable &ST);
289  void EnumerateNamedMetadata(const Module &M);
290};
291
292} // End llvm namespace
293
294#endif
295