1 //===- CodeMetrics.h - Measures the weight of a function---------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements various weight measurements for code, helping
11 // the Inliner and other passes decide whether to duplicate its contents.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_ANALYSIS_CODEMETRICS_H
16 #define LLVM_ANALYSIS_CODEMETRICS_H
18 #include "llvm/ADT/DenseMap.h"
27 // CodeMetrics - Calculate size and a few similar metrics for a set of
30 /// NeverInline - True if this callee should never be inlined into a
34 // True if this function contains a call to setjmp or _setjmp
37 // True if this function calls itself
40 // True if this function contains one or more indirect branches
41 bool containsIndirectBr;
43 /// usesDynamicAlloca - True if this function calls alloca (in the C sense).
44 bool usesDynamicAlloca;
46 /// NumInsts, NumBlocks - Keep track of how large each function is, which
47 /// is used to estimate the code size cost of inlining it.
48 unsigned NumInsts, NumBlocks;
50 /// NumBBInsts - Keeps track of basic block code size estimates.
51 DenseMap<const BasicBlock *, unsigned> NumBBInsts;
53 /// NumCalls - Keep track of the number of calls to 'big' functions.
56 /// NumInlineCandidates - Keep track of the number of calls to internal
57 /// functions with only a single caller. These are likely targets for
58 /// future inlining, likely exposed by interleaved devirtualization.
59 unsigned NumInlineCandidates;
61 /// NumVectorInsts - Keep track of how many instructions produce vector
62 /// values. The inliner is being more aggressive with inlining vector
64 unsigned NumVectorInsts;
66 /// NumRets - Keep track of how many Ret instructions the block contains.
69 CodeMetrics() : callsSetJmp(false), isRecursive(false),
70 containsIndirectBr(false), usesDynamicAlloca(false),
71 NumInsts(0), NumBlocks(0), NumCalls(0),
72 NumInlineCandidates(0), NumVectorInsts(0),
75 /// analyzeBasicBlock - Add information about the specified basic block
76 /// to the current structure.
77 void analyzeBasicBlock(const BasicBlock *BB, const TargetData *TD = 0);
79 /// analyzeFunction - Add information about the specified function
80 /// to the current structure.
81 void analyzeFunction(Function *F, const TargetData *TD = 0);
83 /// CountCodeReductionForConstant - Figure out an approximation for how
84 /// many instructions will be constant folded if the specified value is
86 unsigned CountCodeReductionForConstant(Value *V);
88 /// CountBonusForConstant - Figure out an approximation for how much
89 /// per-call performance boost we can expect if the specified value is
91 unsigned CountBonusForConstant(Value *V);
93 /// CountCodeReductionForAlloca - Figure out an approximation of how much
94 /// smaller the function will be if it is inlined into a context where an
95 /// argument becomes an alloca.
97 unsigned CountCodeReductionForAlloca(Value *V);