• Home
  • History
  • Annotate
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 MDOperand;
38  class NamedMDNode;
39  class AttributeSet;
40  class ValueSymbolTable;
41  class MDSymbolTable;
42  class raw_ostream;
43  
44  class ValueEnumerator {
45  public:
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  
53  private:
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;
MDIndexMDIndex74      explicit MDIndex(unsigned F) : F(F) {}
75  
76      /// Check if this has a function tag, and it's different from NewF.
hasDifferentFunctionMDIndex77      bool hasDifferentFunction(unsigned NewF) const { return F && F != NewF; }
78  
79      /// Fetch the MD this references out of the given metadata array.
getMDIndex80      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;
MDRangeMDRange99      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;
139  public:
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;
getMetadataID(const Metadata * MD)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    }
getMetadataOrNullID(const Metadata * MD)153    unsigned getMetadataOrNullID(const Metadata *MD) const {
154      return MetadataMap.lookup(MD).ID;
155    }
numMDs()156    unsigned numMDs() const { return MDs.size(); }
157  
shouldPreserveUseListOrder()158    bool shouldPreserveUseListOrder() const { return ShouldPreserveUseListOrder; }
159  
getTypeID(Type * T)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  
getAttributeID(AttributeSet PAL)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  
getAttributeGroupID(AttributeSet PAL)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.
getFunctionConstantRange(unsigned & Start,unsigned & End)185    void getFunctionConstantRange(unsigned &Start, unsigned &End) const {
186      Start = FirstFuncConstantID;
187      End = FirstInstID;
188    }
189  
getValues()190    const ValueList &getValues() const { return Values; }
191  
192    /// Check whether the current block has any metadata to emit.
hasMDs()193    bool hasMDs() const { return NumModuleMDs < MDs.size(); }
194  
195    /// Get the MDString metadata for this block.
getMDStrings()196    ArrayRef<const Metadata *> getMDStrings() const {
197      return makeArrayRef(MDs).slice(NumModuleMDs, NumMDStrings);
198    }
199  
200    /// Get the non-MDString metadata for this block.
getNonMDStrings()201    ArrayRef<const Metadata *> getNonMDStrings() const {
202      return makeArrayRef(MDs).slice(NumModuleMDs).slice(NumMDStrings);
203    }
204  
getTypes()205    const TypeList &getTypes() const { return Types; }
getBasicBlocks()206    const std::vector<const BasicBlock*> &getBasicBlocks() const {
207      return BasicBlocks;
208    }
getAttributes()209    const std::vector<AttributeSet> &getAttributes() const {
210      return Attribute;
211    }
getAttributeGroups()212    const std::vector<AttributeSet> &getAttributeGroups() const {
213      return AttributeGroups;
214    }
215  
getComdats()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  
231  private:
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