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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/IR/Module.h"
21 #include "llvm/IR/OptBisect.h"
22 #include "llvm/PassRegistry.h"
23 #include "llvm/Support/Debug.h"
24 #include "llvm/Support/raw_ostream.h"
25 using namespace llvm;
26 
27 #define DEBUG_TYPE "ir"
28 
29 //===----------------------------------------------------------------------===//
30 // Pass Implementation
31 //
32 
33 // Force out-of-line virtual method.
~Pass()34 Pass::~Pass() {
35   delete Resolver;
36 }
37 
38 // Force out-of-line virtual method.
~ModulePass()39 ModulePass::~ModulePass() { }
40 
createPrinterPass(raw_ostream & O,const std::string & Banner) const41 Pass *ModulePass::createPrinterPass(raw_ostream &O,
42                                     const std::string &Banner) const {
43   return createPrintModulePass(O, Banner);
44 }
45 
getPotentialPassManagerType() const46 PassManagerType ModulePass::getPotentialPassManagerType() const {
47   return PMT_ModulePassManager;
48 }
49 
skipModule(Module & M) const50 bool ModulePass::skipModule(Module &M) const {
51   return !M.getContext().getOptBisect().shouldRunPass(this, M);
52 }
53 
mustPreserveAnalysisID(char & AID) const54 bool Pass::mustPreserveAnalysisID(char &AID) const {
55   return Resolver->getAnalysisIfAvailable(&AID, true) != nullptr;
56 }
57 
58 // dumpPassStructure - Implement the -debug-pass=Structure option
dumpPassStructure(unsigned Offset)59 void Pass::dumpPassStructure(unsigned Offset) {
60   dbgs().indent(Offset*2) << getPassName() << "\n";
61 }
62 
63 /// getPassName - Return a nice clean name for a pass.  This usually
64 /// implemented in terms of the name that is registered by one of the
65 /// Registration templates, but can be overloaded directly.
66 ///
getPassName() const67 const char *Pass::getPassName() const {
68   AnalysisID AID =  getPassID();
69   const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(AID);
70   if (PI)
71     return PI->getPassName();
72   return "Unnamed pass: implement Pass::getPassName()";
73 }
74 
preparePassManager(PMStack &)75 void Pass::preparePassManager(PMStack &) {
76   // By default, don't do anything.
77 }
78 
getPotentialPassManagerType() const79 PassManagerType Pass::getPotentialPassManagerType() const {
80   // Default implementation.
81   return PMT_Unknown;
82 }
83 
getAnalysisUsage(AnalysisUsage &) const84 void Pass::getAnalysisUsage(AnalysisUsage &) const {
85   // By default, no analysis results are used, all are invalidated.
86 }
87 
releaseMemory()88 void Pass::releaseMemory() {
89   // By default, don't do anything.
90 }
91 
verifyAnalysis() const92 void Pass::verifyAnalysis() const {
93   // By default, don't do anything.
94 }
95 
getAdjustedAnalysisPointer(AnalysisID AID)96 void *Pass::getAdjustedAnalysisPointer(AnalysisID AID) {
97   return this;
98 }
99 
getAsImmutablePass()100 ImmutablePass *Pass::getAsImmutablePass() {
101   return nullptr;
102 }
103 
getAsPMDataManager()104 PMDataManager *Pass::getAsPMDataManager() {
105   return nullptr;
106 }
107 
setResolver(AnalysisResolver * AR)108 void Pass::setResolver(AnalysisResolver *AR) {
109   assert(!Resolver && "Resolver is already set");
110   Resolver = AR;
111 }
112 
113 // print - Print out the internal state of the pass.  This is called by Analyze
114 // to print out the contents of an analysis.  Otherwise it is not necessary to
115 // implement this method.
116 //
print(raw_ostream & O,const Module *) const117 void Pass::print(raw_ostream &O,const Module*) const {
118   O << "Pass::print not implemented for pass: '" << getPassName() << "'!\n";
119 }
120 
121 // dump - call print(cerr);
dump() const122 LLVM_DUMP_METHOD void Pass::dump() const {
123   print(dbgs(), nullptr);
124 }
125 
126 //===----------------------------------------------------------------------===//
127 // ImmutablePass Implementation
128 //
129 // Force out-of-line virtual method.
~ImmutablePass()130 ImmutablePass::~ImmutablePass() { }
131 
initializePass()132 void ImmutablePass::initializePass() {
133   // By default, don't do anything.
134 }
135 
136 //===----------------------------------------------------------------------===//
137 // FunctionPass Implementation
138 //
139 
createPrinterPass(raw_ostream & O,const std::string & Banner) const140 Pass *FunctionPass::createPrinterPass(raw_ostream &O,
141                                       const std::string &Banner) const {
142   return createPrintFunctionPass(O, Banner);
143 }
144 
getPotentialPassManagerType() const145 PassManagerType FunctionPass::getPotentialPassManagerType() const {
146   return PMT_FunctionPassManager;
147 }
148 
skipFunction(const Function & F) const149 bool FunctionPass::skipFunction(const Function &F) const {
150   if (!F.getContext().getOptBisect().shouldRunPass(this, F))
151     return true;
152 
153   if (F.hasFnAttribute(Attribute::OptimizeNone)) {
154     DEBUG(dbgs() << "Skipping pass '" << getPassName() << "' on function "
155                  << F.getName() << "\n");
156     return true;
157   }
158   return false;
159 }
160 
161 //===----------------------------------------------------------------------===//
162 // BasicBlockPass Implementation
163 //
164 
createPrinterPass(raw_ostream & O,const std::string & Banner) const165 Pass *BasicBlockPass::createPrinterPass(raw_ostream &O,
166                                         const std::string &Banner) const {
167   return createPrintBasicBlockPass(O, Banner);
168 }
169 
doInitialization(Function &)170 bool BasicBlockPass::doInitialization(Function &) {
171   // By default, don't do anything.
172   return false;
173 }
174 
doFinalization(Function &)175 bool BasicBlockPass::doFinalization(Function &) {
176   // By default, don't do anything.
177   return false;
178 }
179 
skipBasicBlock(const BasicBlock & BB) const180 bool BasicBlockPass::skipBasicBlock(const BasicBlock &BB) const {
181   const Function *F = BB.getParent();
182   if (!F)
183     return false;
184   if (!F->getContext().getOptBisect().shouldRunPass(this, BB))
185     return true;
186   if (F->hasFnAttribute(Attribute::OptimizeNone)) {
187     // Report this only once per function.
188     if (&BB == &F->getEntryBlock())
189       DEBUG(dbgs() << "Skipping pass '" << getPassName()
190             << "' on function " << F->getName() << "\n");
191     return true;
192   }
193   return false;
194 }
195 
getPotentialPassManagerType() const196 PassManagerType BasicBlockPass::getPotentialPassManagerType() const {
197   return PMT_BasicBlockPassManager;
198 }
199 
lookupPassInfo(const void * TI)200 const PassInfo *Pass::lookupPassInfo(const void *TI) {
201   return PassRegistry::getPassRegistry()->getPassInfo(TI);
202 }
203 
lookupPassInfo(StringRef Arg)204 const PassInfo *Pass::lookupPassInfo(StringRef Arg) {
205   return PassRegistry::getPassRegistry()->getPassInfo(Arg);
206 }
207 
createPass(AnalysisID ID)208 Pass *Pass::createPass(AnalysisID ID) {
209   const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(ID);
210   if (!PI)
211     return nullptr;
212   return PI->createPass();
213 }
214 
215 //===----------------------------------------------------------------------===//
216 //                  Analysis Group Implementation Code
217 //===----------------------------------------------------------------------===//
218 
219 // RegisterAGBase implementation
220 //
RegisterAGBase(const char * Name,const void * InterfaceID,const void * PassID,bool isDefault)221 RegisterAGBase::RegisterAGBase(const char *Name, const void *InterfaceID,
222                                const void *PassID, bool isDefault)
223     : PassInfo(Name, InterfaceID) {
224   PassRegistry::getPassRegistry()->registerAnalysisGroup(InterfaceID, PassID,
225                                                          *this, isDefault);
226 }
227 
228 //===----------------------------------------------------------------------===//
229 // PassRegistrationListener implementation
230 //
231 
232 // enumeratePasses - Iterate over the registered passes, calling the
233 // passEnumerate callback on each PassInfo object.
234 //
enumeratePasses()235 void PassRegistrationListener::enumeratePasses() {
236   PassRegistry::getPassRegistry()->enumerateWith(this);
237 }
238 
PassNameParser(cl::Option & O)239 PassNameParser::PassNameParser(cl::Option &O)
240     : cl::parser<const PassInfo *>(O) {
241   PassRegistry::getPassRegistry()->addRegistrationListener(this);
242 }
243 
~PassNameParser()244 PassNameParser::~PassNameParser() {
245   // This only gets called during static destruction, in which case the
246   // PassRegistry will have already been destroyed by llvm_shutdown().  So
247   // attempting to remove the registration listener is an error.
248 }
249 
250 //===----------------------------------------------------------------------===//
251 //   AnalysisUsage Class Implementation
252 //
253 
254 namespace {
255   struct GetCFGOnlyPasses : public PassRegistrationListener {
256     typedef AnalysisUsage::VectorType VectorType;
257     VectorType &CFGOnlyList;
GetCFGOnlyPasses__anon7ce531900111::GetCFGOnlyPasses258     GetCFGOnlyPasses(VectorType &L) : CFGOnlyList(L) {}
259 
passEnumerate__anon7ce531900111::GetCFGOnlyPasses260     void passEnumerate(const PassInfo *P) override {
261       if (P->isCFGOnlyPass())
262         CFGOnlyList.push_back(P->getTypeInfo());
263     }
264   };
265 }
266 
267 // setPreservesCFG - This function should be called to by the pass, iff they do
268 // not:
269 //
270 //  1. Add or remove basic blocks from the function
271 //  2. Modify terminator instructions in any way.
272 //
273 // This function annotates the AnalysisUsage info object to say that analyses
274 // that only depend on the CFG are preserved by this pass.
275 //
setPreservesCFG()276 void AnalysisUsage::setPreservesCFG() {
277   // Since this transformation doesn't modify the CFG, it preserves all analyses
278   // that only depend on the CFG (like dominators, loop info, etc...)
279   GetCFGOnlyPasses(Preserved).enumeratePasses();
280 }
281 
addPreserved(StringRef Arg)282 AnalysisUsage &AnalysisUsage::addPreserved(StringRef Arg) {
283   const PassInfo *PI = Pass::lookupPassInfo(Arg);
284   // If the pass exists, preserve it. Otherwise silently do nothing.
285   if (PI) Preserved.push_back(PI->getTypeInfo());
286   return *this;
287 }
288 
addRequiredID(const void * ID)289 AnalysisUsage &AnalysisUsage::addRequiredID(const void *ID) {
290   Required.push_back(ID);
291   return *this;
292 }
293 
addRequiredID(char & ID)294 AnalysisUsage &AnalysisUsage::addRequiredID(char &ID) {
295   Required.push_back(&ID);
296   return *this;
297 }
298 
addRequiredTransitiveID(char & ID)299 AnalysisUsage &AnalysisUsage::addRequiredTransitiveID(char &ID) {
300   Required.push_back(&ID);
301   RequiredTransitive.push_back(&ID);
302   return *this;
303 }
304