1 //===- CodeMetrics.h - Code cost measurements -------------------*- 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 implements various weight measurements for code, helping 11 // the Inliner and other passes decide whether to duplicate its contents. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_ANALYSIS_CODEMETRICS_H 16 #define LLVM_ANALYSIS_CODEMETRICS_H 17 18 #include "llvm/ADT/DenseMap.h" 19 #include "llvm/Support/CallSite.h" 20 21 namespace llvm { 22 class BasicBlock; 23 class Function; 24 class Instruction; 25 class DataLayout; 26 class TargetTransformInfo; 27 class Value; 28 29 /// \brief Check whether a call will lower to something small. 30 /// 31 /// This tests checks whether this callsite will lower to something 32 /// significantly cheaper than a traditional call, often a single 33 /// instruction. Note that if isInstructionFree(CS.getInstruction()) would 34 /// return true, so will this function. 35 bool callIsSmall(ImmutableCallSite CS); 36 37 /// \brief Utility to calculate the size and a few similar metrics for a set 38 /// of basic blocks. 39 struct CodeMetrics { 40 /// \brief True if this function contains a call to setjmp or other functions 41 /// with attribute "returns twice" without having the attribute itself. 42 bool exposesReturnsTwice; 43 44 /// \brief True if this function calls itself. 45 bool isRecursive; 46 47 /// \brief True if this function cannot be duplicated. 48 /// 49 /// True if this function contains one or more indirect branches, or it contains 50 /// one or more 'noduplicate' instructions. 51 bool notDuplicatable; 52 53 /// \brief True if this function calls alloca (in the C sense). 54 bool usesDynamicAlloca; 55 56 /// \brief Number of instructions in the analyzed blocks. 57 unsigned NumInsts; 58 59 /// \brief Number of analyzed blocks. 60 unsigned NumBlocks; 61 62 /// \brief Keeps track of basic block code size estimates. 63 DenseMap<const BasicBlock *, unsigned> NumBBInsts; 64 65 /// \brief Keep track of the number of calls to 'big' functions. 66 unsigned NumCalls; 67 68 /// \brief The number of calls to internal functions with a single caller. 69 /// 70 /// These are likely targets for future inlining, likely exposed by 71 /// interleaved devirtualization. 72 unsigned NumInlineCandidates; 73 74 /// \brief How many instructions produce vector values. 75 /// 76 /// The inliner is more aggressive with inlining vector kernels. 77 unsigned NumVectorInsts; 78 79 /// \brief How many 'ret' instructions the blocks contain. 80 unsigned NumRets; 81 82 CodeMetrics() 83 : exposesReturnsTwice(false), isRecursive(false), notDuplicatable(false), 84 usesDynamicAlloca(false), NumInsts(0), NumBlocks(0), NumCalls(0), 85 NumInlineCandidates(0), NumVectorInsts(0), NumRets(0) {} 86 87 /// \brief Add information about a block to the current state. 88 void analyzeBasicBlock(const BasicBlock *BB, const TargetTransformInfo &TTI); 89 }; 90 91 } 92 93 #endif 94
