1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
|
//===- ProfileDataLoaderPass.cpp - Set branch weight metadata from prof ---===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass loads profiling data from a dump file and sets branch weight
// metadata.
//
// TODO: Replace all "profile-metadata-loader" strings with "profile-loader"
// once ProfileInfo etc. has been removed.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "profile-metadata-loader"
#include "llvm/Analysis/Passes.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/ProfileDataLoader.h"
#include "llvm/BasicBlock.h"
#include "llvm/InstrTypes.h"
#include "llvm/LLVMContext.h"
#include "llvm/MDBuilder.h"
#include "llvm/Metadata.h"
#include "llvm/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
STATISTIC(NumEdgesRead, "The # of edges read.");
STATISTIC(NumTermsAnnotated, "The # of terminator instructions annotated.");
static cl::opt<std::string>
ProfileMetadataFilename("profile-file", cl::init("llvmprof.out"),
cl::value_desc("filename"),
cl::desc("Profile file loaded by -profile-metadata-loader"));
namespace {
/// This pass loads profiling data from a dump file and sets branch weight
/// metadata.
class ProfileMetadataLoaderPass : public ModulePass {
std::string Filename;
public:
static char ID; // Class identification, replacement for typeinfo
explicit ProfileMetadataLoaderPass(const std::string &filename = "")
: ModulePass(ID), Filename(filename) {
initializeProfileMetadataLoaderPassPass(*PassRegistry::getPassRegistry());
if (filename.empty()) Filename = ProfileMetadataFilename;
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
}
virtual const char *getPassName() const {
return "Profile loader";
}
virtual void readEdge(unsigned, ProfileData&, ProfileData::Edge,
ArrayRef<unsigned>);
virtual unsigned matchEdges(Module&, ProfileData&, ArrayRef<unsigned>);
virtual void setBranchWeightMetadata(Module&, ProfileData&);
virtual bool runOnModule(Module &M);
};
} // End of anonymous namespace
char ProfileMetadataLoaderPass::ID = 0;
INITIALIZE_PASS_BEGIN(ProfileMetadataLoaderPass, "profile-metadata-loader",
"Load profile information from llvmprof.out", false, true)
INITIALIZE_PASS_END(ProfileMetadataLoaderPass, "profile-metadata-loader",
"Load profile information from llvmprof.out", false, true)
char &llvm::ProfileMetadataLoaderPassID = ProfileMetadataLoaderPass::ID;
/// createProfileMetadataLoaderPass - This function returns a Pass that loads
/// the profiling information for the module from the specified filename,
/// making it available to the optimizers.
ModulePass *llvm::createProfileMetadataLoaderPass() {
return new ProfileMetadataLoaderPass();
}
ModulePass *llvm::createProfileMetadataLoaderPass(const std::string &Filename) {
return new ProfileMetadataLoaderPass(Filename);
}
/// readEdge - Take the value from a profile counter and assign it to an edge.
void ProfileMetadataLoaderPass::readEdge(unsigned ReadCount,
ProfileData &PB, ProfileData::Edge e,
ArrayRef<unsigned> Counters) {
if (ReadCount >= Counters.size()) return;
unsigned weight = Counters[ReadCount];
assert(weight != ProfileDataLoader::Uncounted);
PB.addEdgeWeight(e, weight);
DEBUG(dbgs() << "-- Read Edge Counter for " << e
<< " (# "<< (ReadCount) << "): "
<< PB.getEdgeWeight(e) << "\n");
}
/// matchEdges - Link every profile counter with an edge.
unsigned ProfileMetadataLoaderPass::matchEdges(Module &M, ProfileData &PB,
ArrayRef<unsigned> Counters) {
if (Counters.size() == 0) return 0;
unsigned ReadCount = 0;
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
if (F->isDeclaration()) continue;
DEBUG(dbgs() << "Loading edges in '" << F->getName() << "'\n");
readEdge(ReadCount++, PB, PB.getEdge(0, &F->getEntryBlock()), Counters);
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
TerminatorInst *TI = BB->getTerminator();
for (unsigned s = 0, e = TI->getNumSuccessors(); s != e; ++s) {
readEdge(ReadCount++, PB, PB.getEdge(BB,TI->getSuccessor(s)),
Counters);
}
}
}
return ReadCount;
}
/// setBranchWeightMetadata - Translate the counter values associated with each
/// edge into branch weights for each conditional branch (a branch with 2 or
/// more desinations).
void ProfileMetadataLoaderPass::setBranchWeightMetadata(Module &M,
ProfileData &PB) {
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
if (F->isDeclaration()) continue;
DEBUG(dbgs() << "Setting branch metadata in '" << F->getName() << "'\n");
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
TerminatorInst *TI = BB->getTerminator();
unsigned NumSuccessors = TI->getNumSuccessors();
// If there is only one successor then we can not set a branch
// probability as the target is certain.
if (NumSuccessors < 2) continue;
// Load the weights of all edges leading from this terminator.
DEBUG(dbgs() << "-- Terminator with " << NumSuccessors
<< " successors:\n");
SmallVector<uint32_t, 4> Weights(NumSuccessors);
for (unsigned s = 0 ; s < NumSuccessors ; ++s) {
ProfileData::Edge edge = PB.getEdge(BB, TI->getSuccessor(s));
Weights[s] = (uint32_t)PB.getEdgeWeight(edge);
DEBUG(dbgs() << "---- Edge '" << edge << "' has weight "
<< Weights[s] << "\n");
}
// Set branch weight metadata. This will set branch probabilities of
// 100%/0% if that is true of the dynamic execution.
// BranchProbabilityInfo can account for this when it loads this metadata
// (it gives the unexectuted branch a weight of 1 for the purposes of
// probability calculations).
MDBuilder MDB(TI->getContext());
MDNode *Node = MDB.createBranchWeights(Weights);
TI->setMetadata(LLVMContext::MD_prof, Node);
NumTermsAnnotated++;
}
}
}
bool ProfileMetadataLoaderPass::runOnModule(Module &M) {
ProfileDataLoader PDL("profile-data-loader", Filename);
ProfileData PB;
ArrayRef<unsigned> Counters = PDL.getRawEdgeCounts();
unsigned ReadCount = matchEdges(M, PB, Counters);
if (ReadCount != Counters.size()) {
M.getContext().emitWarning("profile information is inconsistent "
"with the current program");
}
NumEdgesRead = ReadCount;
setBranchWeightMetadata(M, PB);
return ReadCount > 0;
}
|
