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  1. //===-- BasicBlockSectionsProfileReader.h - BB sections profile reader pass ==//
  2. //
  3. // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  4. // See https://llvm.org/LICENSE.txt for license information.
  5. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  6. //
  7. //===----------------------------------------------------------------------===//
  8. //
  9. // This pass creates the basic block cluster info by reading the basic block
  10. // sections profile. The cluster info will be used by the basic-block-sections
  11. // pass to arrange basic blocks in their sections.
  12. //
  13. //===----------------------------------------------------------------------===//
  14.  
  15. #ifndef LLVM_CODEGEN_BASICBLOCKSECTIONSPROFILEREADER_H
  16. #define LLVM_CODEGEN_BASICBLOCKSECTIONSPROFILEREADER_H
  17.  
  18. #include "llvm/ADT/SmallSet.h"
  19. #include "llvm/ADT/SmallVector.h"
  20. #include "llvm/ADT/StringMap.h"
  21. #include "llvm/ADT/StringRef.h"
  22. #include "llvm/InitializePasses.h"
  23. #include "llvm/Pass.h"
  24. #include "llvm/Support/Error.h"
  25. #include "llvm/Support/LineIterator.h"
  26. #include "llvm/Support/MemoryBuffer.h"
  27.  
  28. using namespace llvm;
  29.  
  30. namespace llvm {
  31.  
  32. // The cluster information for a machine basic block.
  33. struct BBClusterInfo {
  34.   // Unique ID for this basic block.
  35.   unsigned BBID;
  36.   // Cluster ID this basic block belongs to.
  37.   unsigned ClusterID;
  38.   // Position of basic block within the cluster.
  39.   unsigned PositionInCluster;
  40. };
  41.  
  42. using ProgramBBClusterInfoMapTy = StringMap<SmallVector<BBClusterInfo>>;
  43.  
  44. class BasicBlockSectionsProfileReader : public ImmutablePass {
  45. public:
  46.   static char ID;
  47.  
  48.   BasicBlockSectionsProfileReader(const MemoryBuffer *Buf)
  49.       : ImmutablePass(ID), MBuf(Buf) {
  50.     initializeBasicBlockSectionsProfileReaderPass(
  51.         *PassRegistry::getPassRegistry());
  52.   };
  53.  
  54.   BasicBlockSectionsProfileReader() : ImmutablePass(ID) {
  55.     initializeBasicBlockSectionsProfileReaderPass(
  56.         *PassRegistry::getPassRegistry());
  57.   }
  58.  
  59.   StringRef getPassName() const override {
  60.     return "Basic Block Sections Profile Reader";
  61.   }
  62.  
  63.   // Returns true if basic block sections profile exist for function \p
  64.   // FuncName.
  65.   bool isFunctionHot(StringRef FuncName) const;
  66.  
  67.   // Returns a pair with first element representing whether basic block sections
  68.   // profile exist for the function \p FuncName, and the second element
  69.   // representing the basic block sections profile (cluster info) for this
  70.   // function. If the first element is true and the second element is empty, it
  71.   // means unique basic block sections are desired for all basic blocks of the
  72.   // function.
  73.   std::pair<bool, SmallVector<BBClusterInfo>>
  74.   getBBClusterInfoForFunction(StringRef FuncName) const;
  75.  
  76.   /// Read profiles of basic blocks if available here.
  77.   void initializePass() override;
  78.  
  79. private:
  80.   StringRef getAliasName(StringRef FuncName) const {
  81.     auto R = FuncAliasMap.find(FuncName);
  82.     return R == FuncAliasMap.end() ? FuncName : R->second;
  83.   }
  84.  
  85.   // This contains the basic-block-sections profile.
  86.   const MemoryBuffer *MBuf = nullptr;
  87.  
  88.   // This encapsulates the BB cluster information for the whole program.
  89.   //
  90.   // For every function name, it contains the cluster information for (all or
  91.   // some of) its basic blocks. The cluster information for every basic block
  92.   // includes its cluster ID along with the position of the basic block in that
  93.   // cluster.
  94.   ProgramBBClusterInfoMapTy ProgramBBClusterInfo;
  95.  
  96.   // Some functions have alias names. We use this map to find the main alias
  97.   // name for which we have mapping in ProgramBBClusterInfo.
  98.   StringMap<StringRef> FuncAliasMap;
  99. };
  100.  
  101. // Creates a BasicBlockSectionsProfileReader pass to parse the basic block
  102. // sections profile. \p Buf is a memory buffer that contains the list of
  103. // functions and basic block ids to selectively enable basic block sections.
  104. ImmutablePass *
  105. createBasicBlockSectionsProfileReaderPass(const MemoryBuffer *Buf);
  106.  
  107. } // namespace llvm
  108. #endif // LLVM_CODEGEN_BASICBLOCKSECTIONSPROFILEREADER_H
  109.