1 //===- Transforms/Instrumentation.h - Instrumentation passes ----*- 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 defines constructor functions for instrumentation passes.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_TRANSFORMS_INSTRUMENTATION_H
15 #define LLVM_TRANSFORMS_INSTRUMENTATION_H
16 
17 #include "llvm/ADT/StringRef.h"
18 #include "llvm/IR/BasicBlock.h"
19 #include <cassert>
20 #include <cstdint>
21 #include <limits>
22 #include <string>
23 #include <vector>
24 
25 namespace llvm {
26 
27 class Triple;
28 class FunctionPass;
29 class ModulePass;
30 class OptimizationRemarkEmitter;
31 class Comdat;
32 
33 /// Instrumentation passes often insert conditional checks into entry blocks.
34 /// Call this function before splitting the entry block to move instructions
35 /// that must remain in the entry block up before the split point. Static
36 /// allocas and llvm.localescape calls, for example, must remain in the entry
37 /// block.
38 BasicBlock::iterator PrepareToSplitEntryBlock(BasicBlock &BB,
39                                               BasicBlock::iterator IP);
40 
41 // Create a constant for Str so that we can pass it to the run-time lib.
42 GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str,
43                                              bool AllowMerging,
44                                              const char *NamePrefix = "");
45 
46 // Returns F.getComdat() if it exists.
47 // Otherwise creates a new comdat, sets F's comdat, and returns it.
48 // Returns nullptr on failure.
49 Comdat *GetOrCreateFunctionComdat(Function &F, Triple &T,
50                                   const std::string &ModuleId);
51 
52 // Insert GCOV profiling instrumentation
53 struct GCOVOptions {
54   static GCOVOptions getDefault();
55 
56   // Specify whether to emit .gcno files.
57   bool EmitNotes;
58 
59   // Specify whether to modify the program to emit .gcda files when run.
60   bool EmitData;
61 
62   // A four-byte version string. The meaning of a version string is described in
63   // gcc's gcov-io.h
64   char Version[4];
65 
66   // Emit a "cfg checksum" that follows the "line number checksum" of a
67   // function. This affects both .gcno and .gcda files.
68   bool UseCfgChecksum;
69 
70   // Add the 'noredzone' attribute to added runtime library calls.
71   bool NoRedZone;
72 
73   // Emit the name of the function in the .gcda files. This is redundant, as
74   // the function identifier can be used to find the name from the .gcno file.
75   bool FunctionNamesInData;
76 
77   // Emit the exit block immediately after the start block, rather than after
78   // all of the function body's blocks.
79   bool ExitBlockBeforeBody;
80 
81   // Regexes separated by a semi-colon to filter the files to instrument.
82   std::string Filter;
83 
84   // Regexes separated by a semi-colon to filter the files to not instrument.
85   std::string Exclude;
86 };
87 
88 ModulePass *createGCOVProfilerPass(const GCOVOptions &Options =
89                                    GCOVOptions::getDefault());
90 
91 // PGO Instrumention
92 ModulePass *createPGOInstrumentationGenLegacyPass();
93 ModulePass *
94 createPGOInstrumentationUseLegacyPass(StringRef Filename = StringRef(""));
95 ModulePass *createPGOIndirectCallPromotionLegacyPass(bool InLTO = false,
96                                                      bool SamplePGO = false);
97 FunctionPass *createPGOMemOPSizeOptLegacyPass();
98 
99 // The pgo-specific indirect call promotion function declared below is used by
100 // the pgo-driven indirect call promotion and sample profile passes. It's a
101 // wrapper around llvm::promoteCall, et al. that additionally computes !prof
102 // metadata. We place it in a pgo namespace so it's not confused with the
103 // generic utilities.
104 namespace pgo {
105 
106 // Helper function that transforms Inst (either an indirect-call instruction, or
107 // an invoke instruction , to a conditional call to F. This is like:
108 //     if (Inst.CalledValue == F)
109 //        F(...);
110 //     else
111 //        Inst(...);
112 //     end
113 // TotalCount is the profile count value that the instruction executes.
114 // Count is the profile count value that F is the target function.
115 // These two values are used to update the branch weight.
116 // If \p AttachProfToDirectCall is true, a prof metadata is attached to the
117 // new direct call to contain \p Count.
118 // Returns the promoted direct call instruction.
119 Instruction *promoteIndirectCall(Instruction *Inst, Function *F, uint64_t Count,
120                                  uint64_t TotalCount,
121                                  bool AttachProfToDirectCall,
122                                  OptimizationRemarkEmitter *ORE);
123 } // namespace pgo
124 
125 /// Options for the frontend instrumentation based profiling pass.
126 struct InstrProfOptions {
127   // Add the 'noredzone' attribute to added runtime library calls.
128   bool NoRedZone = false;
129 
130   // Do counter register promotion
131   bool DoCounterPromotion = false;
132 
133   // Use atomic profile counter increments.
134   bool Atomic = false;
135 
136   // Name of the profile file to use as output
137   std::string InstrProfileOutput;
138 
139   InstrProfOptions() = default;
140 };
141 
142 /// Insert frontend instrumentation based profiling.
143 ModulePass *createInstrProfilingLegacyPass(
144     const InstrProfOptions &Options = InstrProfOptions());
145 
146 // Insert AddressSanitizer (address sanity checking) instrumentation
147 FunctionPass *createAddressSanitizerFunctionPass(bool CompileKernel = false,
148                                                  bool Recover = false,
149                                                  bool UseAfterScope = false);
150 ModulePass *createAddressSanitizerModulePass(bool CompileKernel = false,
151                                              bool Recover = false,
152                                              bool UseGlobalsGC = true,
153                                              bool UseOdrIndicator = true);
154 
155 FunctionPass *createHWAddressSanitizerPass(bool CompileKernel = false,
156                                            bool Recover = false);
157 
158 // Insert DataFlowSanitizer (dynamic data flow analysis) instrumentation
159 ModulePass *createDataFlowSanitizerPass(
160     const std::vector<std::string> &ABIListFiles = std::vector<std::string>(),
161     void *(*getArgTLS)() = nullptr, void *(*getRetValTLS)() = nullptr);
162 
163 // Options for EfficiencySanitizer sub-tools.
164 struct EfficiencySanitizerOptions {
165   enum Type {
166     ESAN_None = 0,
167     ESAN_CacheFrag,
168     ESAN_WorkingSet,
169   } ToolType = ESAN_None;
170 
171   EfficiencySanitizerOptions() = default;
172 };
173 
174 // Insert EfficiencySanitizer instrumentation.
175 ModulePass *createEfficiencySanitizerPass(
176     const EfficiencySanitizerOptions &Options = EfficiencySanitizerOptions());
177 
178 // Options for sanitizer coverage instrumentation.
179 struct SanitizerCoverageOptions {
180   enum Type {
181     SCK_None = 0,
182     SCK_Function,
183     SCK_BB,
184     SCK_Edge
185   } CoverageType = SCK_None;
186   bool IndirectCalls = false;
187   bool TraceBB = false;
188   bool TraceCmp = false;
189   bool TraceDiv = false;
190   bool TraceGep = false;
191   bool Use8bitCounters = false;
192   bool TracePC = false;
193   bool TracePCGuard = false;
194   bool Inline8bitCounters = false;
195   bool PCTable = false;
196   bool NoPrune = false;
197   bool StackDepth = false;
198 
199   SanitizerCoverageOptions() = default;
200 };
201 
202 // Insert SanitizerCoverage instrumentation.
203 ModulePass *createSanitizerCoverageModulePass(
204     const SanitizerCoverageOptions &Options = SanitizerCoverageOptions());
205 
206 /// Calculate what to divide by to scale counts.
207 ///
208 /// Given the maximum count, calculate a divisor that will scale all the
209 /// weights to strictly less than std::numeric_limits<uint32_t>::max().
calculateCountScale(uint64_t MaxCount)210 static inline uint64_t calculateCountScale(uint64_t MaxCount) {
211   return MaxCount < std::numeric_limits<uint32_t>::max()
212              ? 1
213              : MaxCount / std::numeric_limits<uint32_t>::max() + 1;
214 }
215 
216 /// Scale an individual branch count.
217 ///
218 /// Scale a 64-bit weight down to 32-bits using \c Scale.
219 ///
scaleBranchCount(uint64_t Count,uint64_t Scale)220 static inline uint32_t scaleBranchCount(uint64_t Count, uint64_t Scale) {
221   uint64_t Scaled = Count / Scale;
222   assert(Scaled <= std::numeric_limits<uint32_t>::max() && "overflow 32-bits");
223   return Scaled;
224 }
225 } // end namespace llvm
226 
227 #endif // LLVM_TRANSFORMS_INSTRUMENTATION_H
228