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"
24 // CodeMetrics - Calculate size and a few similar metrics for a set of
27 /// NeverInline - True if this callee should never be inlined into a
31 // True if this function contains a call to setjmp or _setjmp
34 // True if this function calls itself
37 // True if this function contains one or more indirect branches
38 bool containsIndirectBr;
40 /// usesDynamicAlloca - True if this function calls alloca (in the C sense).
41 bool usesDynamicAlloca;
43 /// NumInsts, NumBlocks - Keep track of how large each function is, which
44 /// is used to estimate the code size cost of inlining it.
45 unsigned NumInsts, NumBlocks;
47 /// NumBBInsts - Keeps track of basic block code size estimates.
48 DenseMap<const BasicBlock *, unsigned> NumBBInsts;
50 /// NumCalls - Keep track of the number of calls to 'big' functions.
53 /// NumInlineCandidates - Keep track of the number of calls to internal
54 /// functions with only a single caller. These are likely targets for
55 /// future inlining, likely exposed by interleaved devirtualization.
56 unsigned NumInlineCandidates;
58 /// NumVectorInsts - Keep track of how many instructions produce vector
59 /// values. The inliner is being more aggressive with inlining vector
61 unsigned NumVectorInsts;
63 /// NumRets - Keep track of how many Ret instructions the block contains.
66 CodeMetrics() : callsSetJmp(false), isRecursive(false),
67 containsIndirectBr(false), usesDynamicAlloca(false),
68 NumInsts(0), NumBlocks(0), NumCalls(0),
69 NumInlineCandidates(0), NumVectorInsts(0),
72 /// analyzeBasicBlock - Add information about the specified basic block
73 /// to the current structure.
74 void analyzeBasicBlock(const BasicBlock *BB, const TargetData *TD = 0);
76 /// analyzeFunction - Add information about the specified function
77 /// to the current structure.
78 void analyzeFunction(Function *F, const TargetData *TD = 0);
80 /// CountCodeReductionForConstant - Figure out an approximation for how
81 /// many instructions will be constant folded if the specified value is
83 unsigned CountCodeReductionForConstant(Value *V);
85 /// CountBonusForConstant - Figure out an approximation for how much
86 /// per-call performance boost we can expect if the specified value is
88 unsigned CountBonusForConstant(Value *V);
90 /// CountCodeReductionForAlloca - Figure out an approximation of how much
91 /// smaller the function will be if it is inlined into a context where an
92 /// argument becomes an alloca.
94 unsigned CountCodeReductionForAlloca(Value *V);