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