LLVM  3.7.0
CodeMetrics.h
Go to the documentation of this file.
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.
46 
47  /// \brief True if this function calls itself.
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.
55 
56  /// \brief True if this function calls alloca (in the C sense).
58 
59  /// \brief Number of instructions in the analyzed blocks.
60  unsigned NumInsts;
61 
62  /// \brief Number of analyzed blocks.
63  unsigned NumBlocks;
64 
65  /// \brief Keeps track of basic block code size estimates.
67 
68  /// \brief Keep track of the number of calls to 'big' functions.
69  unsigned NumCalls;
70 
71  /// \brief The number of calls to internal functions with a single caller.
72  ///
73  /// These are likely targets for future inlining, likely exposed by
74  /// interleaved devirtualization.
76 
77  /// \brief How many instructions produce vector values.
78  ///
79  /// The inliner is more aggressive with inlining vector kernels.
80  unsigned NumVectorInsts;
81 
82  /// \brief How many 'ret' instructions the blocks contain.
83  unsigned NumRets;
84 
89 
90  /// \brief Add information about a block to the current state.
91  void analyzeBasicBlock(const BasicBlock *BB, const TargetTransformInfo &TTI,
93 
94  /// \brief Collect a loop's ephemeral values (those used only by an assume
95  /// or similar intrinsics in the loop).
96  static void collectEphemeralValues(const Loop *L, AssumptionCache *AC,
98 
99  /// \brief Collect a functions's ephemeral values (those used only by an
100  /// assume or similar intrinsics in the function).
101  static void collectEphemeralValues(const Function *L, AssumptionCache *AC,
102  SmallPtrSetImpl<const Value *> &EphValues);
103 };
104 
105 }
106 
107 #endif
Various leaf nodes.
Definition: ISDOpcodes.h:60
bool isRecursive
True if this function calls itself.
Definition: CodeMetrics.h:48
unsigned NumVectorInsts
How many instructions produce vector values.
Definition: CodeMetrics.h:80
unsigned NumCalls
Keep track of the number of calls to 'big' functions.
Definition: CodeMetrics.h:69
A cache of .assume calls within a function.
unsigned NumInlineCandidates
The number of calls to internal functions with a single caller.
Definition: CodeMetrics.h:75
bool notDuplicatable
True if this function cannot be duplicated.
Definition: CodeMetrics.h:54
A templated base class for SmallPtrSet which provides the typesafe interface that is common across al...
Definition: SmallPtrSet.h:242
unsigned NumBlocks
Number of analyzed blocks.
Definition: CodeMetrics.h:63
#define false
Definition: ConvertUTF.c:65
bool usesDynamicAlloca
True if this function calls alloca (in the C sense).
Definition: CodeMetrics.h:57
void analyzeBasicBlock(const BasicBlock *BB, const TargetTransformInfo &TTI, SmallPtrSetImpl< const Value * > &EphValues)
Add information about a block to the current state.
LLVM Basic Block Representation.
Definition: BasicBlock.h:65
DenseMap< const BasicBlock *, unsigned > NumBBInsts
Keeps track of basic block code size estimates.
Definition: CodeMetrics.h:66
This pass provides access to the codegen interfaces that are needed for IR-level transformations.
bool exposesReturnsTwice
True if this function contains a call to setjmp or other functions with attribute "returns twice" wit...
Definition: CodeMetrics.h:45
Utility to calculate the size and a few similar metrics for a set of basic blocks.
Definition: CodeMetrics.h:42
unsigned NumRets
How many 'ret' instructions the blocks contain.
Definition: CodeMetrics.h:83
bool callIsSmall(ImmutableCallSite CS)
Check whether a call will lower to something small.
static void collectEphemeralValues(const Loop *L, AssumptionCache *AC, SmallPtrSetImpl< const Value * > &EphValues)
Collect a loop's ephemeral values (those used only by an assume or similar intrinsics in the loop)...
Definition: CodeMetrics.cpp:70
unsigned NumInsts
Number of instructions in the analyzed blocks.
Definition: CodeMetrics.h:60