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1 //===- Pass.cpp - LLVM Pass Infrastructure Implementation -----------------===//
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 the LLVM Pass infrastructure.  It is primarily
11 // responsible with ensuring that passes are executed and batched together
12 // optimally.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "llvm/Pass.h"
17 #include "llvm/IR/Function.h"
18 #include "llvm/IR/IRPrintingPasses.h"
19 #include "llvm/IR/LegacyPassNameParser.h"
20 #include "llvm/PassRegistry.h"
21 #include "llvm/Support/Debug.h"
22 #include "llvm/Support/raw_ostream.h"
23 using namespace llvm;
24 
25 #define DEBUG_TYPE "ir"
26 
27 //===----------------------------------------------------------------------===//
28 // Pass Implementation
29 //
30 
31 // Force out-of-line virtual method.
~Pass()32 Pass::~Pass() {
33   delete Resolver;
34 }
35 
36 // Force out-of-line virtual method.
~ModulePass()37 ModulePass::~ModulePass() { }
38 
createPrinterPass(raw_ostream & O,const std::string & Banner) const39 Pass *ModulePass::createPrinterPass(raw_ostream &O,
40                                     const std::string &Banner) const {
41   return createPrintModulePass(O, Banner);
42 }
43 
getPotentialPassManagerType() const44 PassManagerType ModulePass::getPotentialPassManagerType() const {
45   return PMT_ModulePassManager;
46 }
47 
mustPreserveAnalysisID(char & AID) const48 bool Pass::mustPreserveAnalysisID(char &AID) const {
49   return Resolver->getAnalysisIfAvailable(&AID, true) != nullptr;
50 }
51 
52 // dumpPassStructure - Implement the -debug-pass=Structure option
dumpPassStructure(unsigned Offset)53 void Pass::dumpPassStructure(unsigned Offset) {
54   dbgs().indent(Offset*2) << getPassName() << "\n";
55 }
56 
57 /// getPassName - Return a nice clean name for a pass.  This usually
58 /// implemented in terms of the name that is registered by one of the
59 /// Registration templates, but can be overloaded directly.
60 ///
getPassName() const61 const char *Pass::getPassName() const {
62   AnalysisID AID =  getPassID();
63   const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(AID);
64   if (PI)
65     return PI->getPassName();
66   return "Unnamed pass: implement Pass::getPassName()";
67 }
68 
preparePassManager(PMStack &)69 void Pass::preparePassManager(PMStack &) {
70   // By default, don't do anything.
71 }
72 
getPotentialPassManagerType() const73 PassManagerType Pass::getPotentialPassManagerType() const {
74   // Default implementation.
75   return PMT_Unknown;
76 }
77 
getAnalysisUsage(AnalysisUsage &) const78 void Pass::getAnalysisUsage(AnalysisUsage &) const {
79   // By default, no analysis results are used, all are invalidated.
80 }
81 
releaseMemory()82 void Pass::releaseMemory() {
83   // By default, don't do anything.
84 }
85 
verifyAnalysis() const86 void Pass::verifyAnalysis() const {
87   // By default, don't do anything.
88 }
89 
getAdjustedAnalysisPointer(AnalysisID AID)90 void *Pass::getAdjustedAnalysisPointer(AnalysisID AID) {
91   return this;
92 }
93 
getAsImmutablePass()94 ImmutablePass *Pass::getAsImmutablePass() {
95   return nullptr;
96 }
97 
getAsPMDataManager()98 PMDataManager *Pass::getAsPMDataManager() {
99   return nullptr;
100 }
101 
setResolver(AnalysisResolver * AR)102 void Pass::setResolver(AnalysisResolver *AR) {
103   assert(!Resolver && "Resolver is already set");
104   Resolver = AR;
105 }
106 
107 // print - Print out the internal state of the pass.  This is called by Analyze
108 // to print out the contents of an analysis.  Otherwise it is not necessary to
109 // implement this method.
110 //
print(raw_ostream & O,const Module *) const111 void Pass::print(raw_ostream &O,const Module*) const {
112   O << "Pass::print not implemented for pass: '" << getPassName() << "'!\n";
113 }
114 
115 // dump - call print(cerr);
dump() const116 void Pass::dump() const {
117   print(dbgs(), nullptr);
118 }
119 
120 //===----------------------------------------------------------------------===//
121 // ImmutablePass Implementation
122 //
123 // Force out-of-line virtual method.
~ImmutablePass()124 ImmutablePass::~ImmutablePass() { }
125 
initializePass()126 void ImmutablePass::initializePass() {
127   // By default, don't do anything.
128 }
129 
130 //===----------------------------------------------------------------------===//
131 // FunctionPass Implementation
132 //
133 
createPrinterPass(raw_ostream & O,const std::string & Banner) const134 Pass *FunctionPass::createPrinterPass(raw_ostream &O,
135                                       const std::string &Banner) const {
136   return createPrintFunctionPass(O, Banner);
137 }
138 
getPotentialPassManagerType() const139 PassManagerType FunctionPass::getPotentialPassManagerType() const {
140   return PMT_FunctionPassManager;
141 }
142 
skipOptnoneFunction(const Function & F) const143 bool FunctionPass::skipOptnoneFunction(const Function &F) const {
144   if (F.hasFnAttribute(Attribute::OptimizeNone)) {
145     DEBUG(dbgs() << "Skipping pass '" << getPassName()
146           << "' on function " << F.getName() << "\n");
147     return true;
148   }
149   return false;
150 }
151 
152 //===----------------------------------------------------------------------===//
153 // BasicBlockPass Implementation
154 //
155 
createPrinterPass(raw_ostream & O,const std::string & Banner) const156 Pass *BasicBlockPass::createPrinterPass(raw_ostream &O,
157                                         const std::string &Banner) const {
158   return createPrintBasicBlockPass(O, Banner);
159 }
160 
doInitialization(Function &)161 bool BasicBlockPass::doInitialization(Function &) {
162   // By default, don't do anything.
163   return false;
164 }
165 
doFinalization(Function &)166 bool BasicBlockPass::doFinalization(Function &) {
167   // By default, don't do anything.
168   return false;
169 }
170 
skipOptnoneFunction(const BasicBlock & BB) const171 bool BasicBlockPass::skipOptnoneFunction(const BasicBlock &BB) const {
172   const Function *F = BB.getParent();
173   if (F && F->hasFnAttribute(Attribute::OptimizeNone)) {
174     // Report this only once per function.
175     if (&BB == &F->getEntryBlock())
176       DEBUG(dbgs() << "Skipping pass '" << getPassName()
177             << "' on function " << F->getName() << "\n");
178     return true;
179   }
180   return false;
181 }
182 
getPotentialPassManagerType() const183 PassManagerType BasicBlockPass::getPotentialPassManagerType() const {
184   return PMT_BasicBlockPassManager;
185 }
186 
lookupPassInfo(const void * TI)187 const PassInfo *Pass::lookupPassInfo(const void *TI) {
188   return PassRegistry::getPassRegistry()->getPassInfo(TI);
189 }
190 
lookupPassInfo(StringRef Arg)191 const PassInfo *Pass::lookupPassInfo(StringRef Arg) {
192   return PassRegistry::getPassRegistry()->getPassInfo(Arg);
193 }
194 
createPass(AnalysisID ID)195 Pass *Pass::createPass(AnalysisID ID) {
196   const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(ID);
197   if (!PI)
198     return nullptr;
199   return PI->createPass();
200 }
201 
202 //===----------------------------------------------------------------------===//
203 //                  Analysis Group Implementation Code
204 //===----------------------------------------------------------------------===//
205 
206 // RegisterAGBase implementation
207 //
RegisterAGBase(const char * Name,const void * InterfaceID,const void * PassID,bool isDefault)208 RegisterAGBase::RegisterAGBase(const char *Name, const void *InterfaceID,
209                                const void *PassID, bool isDefault)
210     : PassInfo(Name, InterfaceID) {
211   PassRegistry::getPassRegistry()->registerAnalysisGroup(InterfaceID, PassID,
212                                                          *this, isDefault);
213 }
214 
215 //===----------------------------------------------------------------------===//
216 // PassRegistrationListener implementation
217 //
218 
219 // enumeratePasses - Iterate over the registered passes, calling the
220 // passEnumerate callback on each PassInfo object.
221 //
enumeratePasses()222 void PassRegistrationListener::enumeratePasses() {
223   PassRegistry::getPassRegistry()->enumerateWith(this);
224 }
225 
PassNameParser(cl::Option & O)226 PassNameParser::PassNameParser(cl::Option &O)
227     : cl::parser<const PassInfo *>(O) {
228   PassRegistry::getPassRegistry()->addRegistrationListener(this);
229 }
230 
~PassNameParser()231 PassNameParser::~PassNameParser() {
232   // This only gets called during static destruction, in which case the
233   // PassRegistry will have already been destroyed by llvm_shutdown().  So
234   // attempting to remove the registration listener is an error.
235 }
236 
237 //===----------------------------------------------------------------------===//
238 //   AnalysisUsage Class Implementation
239 //
240 
241 namespace {
242   struct GetCFGOnlyPasses : public PassRegistrationListener {
243     typedef AnalysisUsage::VectorType VectorType;
244     VectorType &CFGOnlyList;
GetCFGOnlyPasses__anon28df2bd40111::GetCFGOnlyPasses245     GetCFGOnlyPasses(VectorType &L) : CFGOnlyList(L) {}
246 
passEnumerate__anon28df2bd40111::GetCFGOnlyPasses247     void passEnumerate(const PassInfo *P) override {
248       if (P->isCFGOnlyPass())
249         CFGOnlyList.push_back(P->getTypeInfo());
250     }
251   };
252 }
253 
254 // setPreservesCFG - This function should be called to by the pass, iff they do
255 // not:
256 //
257 //  1. Add or remove basic blocks from the function
258 //  2. Modify terminator instructions in any way.
259 //
260 // This function annotates the AnalysisUsage info object to say that analyses
261 // that only depend on the CFG are preserved by this pass.
262 //
setPreservesCFG()263 void AnalysisUsage::setPreservesCFG() {
264   // Since this transformation doesn't modify the CFG, it preserves all analyses
265   // that only depend on the CFG (like dominators, loop info, etc...)
266   GetCFGOnlyPasses(Preserved).enumeratePasses();
267 }
268 
addPreserved(StringRef Arg)269 AnalysisUsage &AnalysisUsage::addPreserved(StringRef Arg) {
270   const PassInfo *PI = Pass::lookupPassInfo(Arg);
271   // If the pass exists, preserve it. Otherwise silently do nothing.
272   if (PI) Preserved.push_back(PI->getTypeInfo());
273   return *this;
274 }
275 
addRequiredID(const void * ID)276 AnalysisUsage &AnalysisUsage::addRequiredID(const void *ID) {
277   Required.push_back(ID);
278   return *this;
279 }
280 
addRequiredID(char & ID)281 AnalysisUsage &AnalysisUsage::addRequiredID(char &ID) {
282   Required.push_back(&ID);
283   return *this;
284 }
285 
addRequiredTransitiveID(char & ID)286 AnalysisUsage &AnalysisUsage::addRequiredTransitiveID(char &ID) {
287   Required.push_back(&ID);
288   RequiredTransitive.push_back(&ID);
289   return *this;
290 }
291