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      1 //===---- llvm/MDBuilder.h - Builder for LLVM metadata ----------*- 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 file defines the MDBuilder class, which is used as a convenient way to
     11 // create LLVM metadata with a consistent and simplified interface.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #ifndef LLVM_IR_MDBUILDER_H
     16 #define LLVM_IR_MDBUILDER_H
     17 
     18 #include "llvm/ADT/DenseSet.h"
     19 #include "llvm/ADT/StringRef.h"
     20 #include "llvm/IR/GlobalValue.h"
     21 #include "llvm/Support/DataTypes.h"
     22 #include <utility>
     23 
     24 namespace llvm {
     25 
     26 class APInt;
     27 template <typename T> class ArrayRef;
     28 class LLVMContext;
     29 class Constant;
     30 class ConstantAsMetadata;
     31 class MDNode;
     32 class MDString;
     33 
     34 class MDBuilder {
     35   LLVMContext &Context;
     36 
     37 public:
     38   MDBuilder(LLVMContext &context) : Context(context) {}
     39 
     40   /// \brief Return the given string as metadata.
     41   MDString *createString(StringRef Str);
     42 
     43   /// \brief Return the given constant as metadata.
     44   ConstantAsMetadata *createConstant(Constant *C);
     45 
     46   //===------------------------------------------------------------------===//
     47   // FPMath metadata.
     48   //===------------------------------------------------------------------===//
     49 
     50   /// \brief Return metadata with the given settings.  The special value 0.0
     51   /// for the Accuracy parameter indicates the default (maximal precision)
     52   /// setting.
     53   MDNode *createFPMath(float Accuracy);
     54 
     55   //===------------------------------------------------------------------===//
     56   // Prof metadata.
     57   //===------------------------------------------------------------------===//
     58 
     59   /// \brief Return metadata containing two branch weights.
     60   MDNode *createBranchWeights(uint32_t TrueWeight, uint32_t FalseWeight);
     61 
     62   /// \brief Return metadata containing a number of branch weights.
     63   MDNode *createBranchWeights(ArrayRef<uint32_t> Weights);
     64 
     65   /// Return metadata specifying that a branch or switch is unpredictable.
     66   MDNode *createUnpredictable();
     67 
     68   /// Return metadata containing the entry \p Count for a function, and the
     69   /// GUIDs stored in \p Imports that need to be imported for sample PGO, to
     70   /// enable the same inlines as the profiled optimized binary
     71   MDNode *createFunctionEntryCount(uint64_t Count,
     72                                    const DenseSet<GlobalValue::GUID> *Imports);
     73 
     74   /// Return metadata containing the section prefix for a function.
     75   MDNode *createFunctionSectionPrefix(StringRef Prefix);
     76 
     77   //===------------------------------------------------------------------===//
     78   // Range metadata.
     79   //===------------------------------------------------------------------===//
     80 
     81   /// \brief Return metadata describing the range [Lo, Hi).
     82   MDNode *createRange(const APInt &Lo, const APInt &Hi);
     83 
     84   /// \brief Return metadata describing the range [Lo, Hi).
     85   MDNode *createRange(Constant *Lo, Constant *Hi);
     86 
     87   //===------------------------------------------------------------------===//
     88   // Callees metadata.
     89   //===------------------------------------------------------------------===//
     90 
     91   /// \brief Return metadata indicating the possible callees of indirect
     92   /// calls.
     93   MDNode *createCallees(ArrayRef<Function *> Callees);
     94 
     95   //===------------------------------------------------------------------===//
     96   // AA metadata.
     97   //===------------------------------------------------------------------===//
     98 
     99 protected:
    100   /// \brief Return metadata appropriate for a AA root node (scope or TBAA).
    101   /// Each returned node is distinct from all other metadata and will never
    102   /// be identified (uniqued) with anything else.
    103   MDNode *createAnonymousAARoot(StringRef Name = StringRef(),
    104                                 MDNode *Extra = nullptr);
    105 
    106 public:
    107   /// \brief Return metadata appropriate for a TBAA root node. Each returned
    108   /// node is distinct from all other metadata and will never be identified
    109   /// (uniqued) with anything else.
    110   MDNode *createAnonymousTBAARoot() {
    111     return createAnonymousAARoot();
    112   }
    113 
    114   /// \brief Return metadata appropriate for an alias scope domain node.
    115   /// Each returned node is distinct from all other metadata and will never
    116   /// be identified (uniqued) with anything else.
    117   MDNode *createAnonymousAliasScopeDomain(StringRef Name = StringRef()) {
    118     return createAnonymousAARoot(Name);
    119   }
    120 
    121   /// \brief Return metadata appropriate for an alias scope root node.
    122   /// Each returned node is distinct from all other metadata and will never
    123   /// be identified (uniqued) with anything else.
    124   MDNode *createAnonymousAliasScope(MDNode *Domain,
    125                                     StringRef Name = StringRef()) {
    126     return createAnonymousAARoot(Name, Domain);
    127   }
    128 
    129   /// \brief Return metadata appropriate for a TBAA root node with the given
    130   /// name.  This may be identified (uniqued) with other roots with the same
    131   /// name.
    132   MDNode *createTBAARoot(StringRef Name);
    133 
    134   /// \brief Return metadata appropriate for an alias scope domain node with
    135   /// the given name. This may be identified (uniqued) with other roots with
    136   /// the same name.
    137   MDNode *createAliasScopeDomain(StringRef Name);
    138 
    139   /// \brief Return metadata appropriate for an alias scope node with
    140   /// the given name. This may be identified (uniqued) with other scopes with
    141   /// the same name and domain.
    142   MDNode *createAliasScope(StringRef Name, MDNode *Domain);
    143 
    144   /// \brief Return metadata for a non-root TBAA node with the given name,
    145   /// parent in the TBAA tree, and value for 'pointsToConstantMemory'.
    146   MDNode *createTBAANode(StringRef Name, MDNode *Parent,
    147                          bool isConstant = false);
    148 
    149   struct TBAAStructField {
    150     uint64_t Offset;
    151     uint64_t Size;
    152     MDNode *TBAA;
    153     TBAAStructField(uint64_t Offset, uint64_t Size, MDNode *TBAA) :
    154       Offset(Offset), Size(Size), TBAA(TBAA) {}
    155   };
    156 
    157   /// \brief Return metadata for a tbaa.struct node with the given
    158   /// struct field descriptions.
    159   MDNode *createTBAAStructNode(ArrayRef<TBAAStructField> Fields);
    160 
    161   /// \brief Return metadata for a TBAA struct node in the type DAG
    162   /// with the given name, a list of pairs (offset, field type in the type DAG).
    163   MDNode *
    164   createTBAAStructTypeNode(StringRef Name,
    165                            ArrayRef<std::pair<MDNode *, uint64_t>> Fields);
    166 
    167   /// \brief Return metadata for a TBAA scalar type node with the
    168   /// given name, an offset and a parent in the TBAA type DAG.
    169   MDNode *createTBAAScalarTypeNode(StringRef Name, MDNode *Parent,
    170                                    uint64_t Offset = 0);
    171 
    172   /// \brief Return metadata for a TBAA tag node with the given
    173   /// base type, access type and offset relative to the base type.
    174   MDNode *createTBAAStructTagNode(MDNode *BaseType, MDNode *AccessType,
    175                                   uint64_t Offset, bool IsConstant = false);
    176 };
    177 
    178 } // end namespace llvm
    179 
    180 #endif
    181