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/ADT/SmallPtrSet.h" 20 #include "llvm/IR/CallSite.h" 21 22 namespace llvm { 23 class AssumptionCache; 24 class BasicBlock; 25 class Loop; 26 class Function; 27 class Instruction; 28 class DataLayout; 29 class TargetTransformInfo; 30 class Value; 31 32 /// \brief Check whether a call will lower to something small. 33 /// 34 /// This tests checks whether this callsite will lower to something 35 /// significantly cheaper than a traditional call, often a single 36 /// instruction. Note that if isInstructionFree(CS.getInstruction()) would 37 /// return true, so will this function. 38 bool callIsSmall(ImmutableCallSite CS); 39 40 /// \brief Utility to calculate the size and a few similar metrics for a set 41 /// of basic blocks. 42 struct CodeMetrics { 43 /// \brief True if this function contains a call to setjmp or other functions 44 /// with attribute "returns twice" without having the attribute itself. 45 bool exposesReturnsTwice = false; 46 47 /// \brief True if this function calls itself. 48 bool isRecursive = false; 49 50 /// \brief True if this function cannot be duplicated. 51 /// 52 /// True if this function contains one or more indirect branches, or it contains 53 /// one or more 'noduplicate' instructions. 54 bool notDuplicatable = false; 55 56 /// \brief True if this function contains a call to a convergent function. 57 bool convergent = false; 58 59 /// \brief True if this function calls alloca (in the C sense). 60 bool usesDynamicAlloca = false; 61 62 /// \brief Number of instructions in the analyzed blocks. 63 unsigned NumInsts = false; 64 65 /// \brief Number of analyzed blocks. 66 unsigned NumBlocks = false; 67 68 /// \brief Keeps track of basic block code size estimates. 69 DenseMap<const BasicBlock *, unsigned> NumBBInsts; 70 71 /// \brief Keep track of the number of calls to 'big' functions. 72 unsigned NumCalls = false; 73 74 /// \brief The number of calls to internal functions with a single caller. 75 /// 76 /// These are likely targets for future inlining, likely exposed by 77 /// interleaved devirtualization. 78 unsigned NumInlineCandidates = 0; 79 80 /// \brief How many instructions produce vector values. 81 /// 82 /// The inliner is more aggressive with inlining vector kernels. 83 unsigned NumVectorInsts = 0; 84 85 /// \brief How many 'ret' instructions the blocks contain. 86 unsigned NumRets = 0; 87 88 /// \brief Add information about a block to the current state. 89 void analyzeBasicBlock(const BasicBlock *BB, const TargetTransformInfo &TTI, 90 const SmallPtrSetImpl<const Value*> &EphValues); 91 92 /// \brief Collect a loop's ephemeral values (those used only by an assume 93 /// or similar intrinsics in the loop). 94 static void collectEphemeralValues(const Loop *L, AssumptionCache *AC, 95 SmallPtrSetImpl<const Value *> &EphValues); 96 97 /// \brief Collect a functions's ephemeral values (those used only by an 98 /// assume or similar intrinsics in the function). 99 static void collectEphemeralValues(const Function *L, AssumptionCache *AC, 100 SmallPtrSetImpl<const Value *> &EphValues); 101 }; 102 103 } 104 105 #endif 106
