Instrumentation.h revision 360784 
1//===- Transforms/Instrumentation.h - Instrumentation passes ----*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines constructor functions for instrumentation passes.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_TRANSFORMS_INSTRUMENTATION_H
14#define LLVM_TRANSFORMS_INSTRUMENTATION_H
15
16#include "llvm/ADT/StringRef.h"
17#include "llvm/IR/BasicBlock.h"
18#include <cassert>
19#include <cstdint>
20#include <limits>
21#include <string>
22#include <vector>
23
24namespace llvm {
25
26class Triple;
27class FunctionPass;
28class ModulePass;
29class OptimizationRemarkEmitter;
30class Comdat;
31
32/// Instrumentation passes often insert conditional checks into entry blocks.
33/// Call this function before splitting the entry block to move instructions
34/// that must remain in the entry block up before the split point. Static
35/// allocas and llvm.localescape calls, for example, must remain in the entry
36/// block.
37BasicBlock::iterator PrepareToSplitEntryBlock(BasicBlock &BB,
38                                              BasicBlock::iterator IP);
39
40// Create a constant for Str so that we can pass it to the run-time lib.
41GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str,
42                                             bool AllowMerging,
43                                             const char *NamePrefix = "");
44
45// Returns F.getComdat() if it exists.
46// Otherwise creates a new comdat, sets F's comdat, and returns it.
47// Returns nullptr on failure.
48Comdat *GetOrCreateFunctionComdat(Function &F, Triple &T,
49                                  const std::string &ModuleId);
50
51// Insert GCOV profiling instrumentation
52struct GCOVOptions {
53  static GCOVOptions getDefault();
54
55  // Specify whether to emit .gcno files.
56  bool EmitNotes;
57
58  // Specify whether to modify the program to emit .gcda files when run.
59  bool EmitData;
60
61  // A four-byte version string. The meaning of a version string is described in
62  // gcc's gcov-io.h
63  char Version[4];
64
65  // Emit a "cfg checksum" that follows the "line number checksum" of a
66  // function. This affects both .gcno and .gcda files.
67  bool UseCfgChecksum;
68
69  // Add the 'noredzone' attribute to added runtime library calls.
70  bool NoRedZone;
71
72  // Emit the name of the function in the .gcda files. This is redundant, as
73  // the function identifier can be used to find the name from the .gcno file.
74  bool FunctionNamesInData;
75
76  // Emit the exit block immediately after the start block, rather than after
77  // all of the function body's blocks.
78  bool ExitBlockBeforeBody;
79
80  // Regexes separated by a semi-colon to filter the files to instrument.
81  std::string Filter;
82
83  // Regexes separated by a semi-colon to filter the files to not instrument.
84  std::string Exclude;
85};
86
87ModulePass *createGCOVProfilerPass(const GCOVOptions &Options =
88                                   GCOVOptions::getDefault());
89
90// PGO Instrumention. Parameter IsCS indicates if this is the context senstive
91// instrumentation.
92ModulePass *createPGOInstrumentationGenLegacyPass(bool IsCS = false);
93ModulePass *
94createPGOInstrumentationUseLegacyPass(StringRef Filename = StringRef(""),
95                                      bool IsCS = false);
96ModulePass *createPGOInstrumentationGenCreateVarLegacyPass(
97    StringRef CSInstrName = StringRef(""));
98ModulePass *createPGOIndirectCallPromotionLegacyPass(bool InLTO = false,
99                                                     bool SamplePGO = false);
100FunctionPass *createPGOMemOPSizeOptLegacyPass();
101
102// The pgo-specific indirect call promotion function declared below is used by
103// the pgo-driven indirect call promotion and sample profile passes. It's a
104// wrapper around llvm::promoteCall, et al. that additionally computes !prof
105// metadata. We place it in a pgo namespace so it's not confused with the
106// generic utilities.
107namespace pgo {
108
109// Helper function that transforms Inst (either an indirect-call instruction, or
110// an invoke instruction , to a conditional call to F. This is like:
111//     if (Inst.CalledValue == F)
112//        F(...);
113//     else
114//        Inst(...);
115//     end
116// TotalCount is the profile count value that the instruction executes.
117// Count is the profile count value that F is the target function.
118// These two values are used to update the branch weight.
119// If \p AttachProfToDirectCall is true, a prof metadata is attached to the
120// new direct call to contain \p Count.
121// Returns the promoted direct call instruction.
122Instruction *promoteIndirectCall(Instruction *Inst, Function *F, uint64_t Count,
123                                 uint64_t TotalCount,
124                                 bool AttachProfToDirectCall,
125                                 OptimizationRemarkEmitter *ORE);
126} // namespace pgo
127
128/// Options for the frontend instrumentation based profiling pass.
129struct InstrProfOptions {
130  // Add the 'noredzone' attribute to added runtime library calls.
131  bool NoRedZone = false;
132
133  // Do counter register promotion
134  bool DoCounterPromotion = false;
135
136  // Use atomic profile counter increments.
137  bool Atomic = false;
138
139  // Use BFI to guide register promotion
140  bool UseBFIInPromotion = false;
141
142  // Name of the profile file to use as output
143  std::string InstrProfileOutput;
144
145  InstrProfOptions() = default;
146};
147
148/// Insert frontend instrumentation based profiling. Parameter IsCS indicates if
149// this is the context senstive instrumentation.
150ModulePass *createInstrProfilingLegacyPass(
151    const InstrProfOptions &Options = InstrProfOptions(), bool IsCS = false);
152
153ModulePass *createInstrOrderFilePass();
154
155// Insert DataFlowSanitizer (dynamic data flow analysis) instrumentation
156ModulePass *createDataFlowSanitizerPass(
157    const std::vector<std::string> &ABIListFiles = std::vector<std::string>(),
158    void *(*getArgTLS)() = nullptr, void *(*getRetValTLS)() = nullptr);
159
160// Options for sanitizer coverage instrumentation.
161struct SanitizerCoverageOptions {
162  enum Type {
163    SCK_None = 0,
164    SCK_Function,
165    SCK_BB,
166    SCK_Edge
167  } CoverageType = SCK_None;
168  bool IndirectCalls = false;
169  bool TraceBB = false;
170  bool TraceCmp = false;
171  bool TraceDiv = false;
172  bool TraceGep = false;
173  bool Use8bitCounters = false;
174  bool TracePC = false;
175  bool TracePCGuard = false;
176  bool Inline8bitCounters = false;
177  bool PCTable = false;
178  bool NoPrune = false;
179  bool StackDepth = false;
180
181  SanitizerCoverageOptions() = default;
182};
183
184/// Calculate what to divide by to scale counts.
185///
186/// Given the maximum count, calculate a divisor that will scale all the
187/// weights to strictly less than std::numeric_limits<uint32_t>::max().
188static inline uint64_t calculateCountScale(uint64_t MaxCount) {
189  return MaxCount < std::numeric_limits<uint32_t>::max()
190             ? 1
191             : MaxCount / std::numeric_limits<uint32_t>::max() + 1;
192}
193
194/// Scale an individual branch count.
195///
196/// Scale a 64-bit weight down to 32-bits using \c Scale.
197///
198static inline uint32_t scaleBranchCount(uint64_t Count, uint64_t Scale) {
199  uint64_t Scaled = Count / Scale;
200  assert(Scaled <= std::numeric_limits<uint32_t>::max() && "overflow 32-bits");
201  return Scaled;
202}
203} // end namespace llvm
204
205#endif // LLVM_TRANSFORMS_INSTRUMENTATION_H
206