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