lib/IR/Pass.cpp

   1 //===- Pass.cpp - LLVM Pass Infrastructure Implementation -----------------===//
   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 implements the LLVM Pass infrastructure.  It is primarily
  10 // responsible with ensuring that passes are executed and batched together
  11 // optimally.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/Pass.h"
  16 #include "llvm/Config/llvm-config.h"
  17 #include "llvm/IR/Attributes.h"
  18 #include "llvm/IR/BasicBlock.h"
  19 #include "llvm/IR/Function.h"
  20 #include "llvm/IR/IRPrintingPasses.h"
  21 #include "llvm/IR/LLVMContext.h"
  22 #include "llvm/IR/LegacyPassNameParser.h"
  23 #include "llvm/IR/Module.h"
  24 #include "llvm/IR/OptBisect.h"
  25 #include "llvm/PassInfo.h"
  26 #include "llvm/PassRegistry.h"
  27 #include "llvm/PassSupport.h"
  28 #include "llvm/Support/Compiler.h"
  29 #include "llvm/Support/Debug.h"
  30 #include "llvm/Support/raw_ostream.h"
  31 #include <cassert>
  32
  33 using namespace llvm;
  34
  35 #define DEBUG_TYPE "ir"
  36
  37 //===----------------------------------------------------------------------===//
  38 // Pass Implementation
  39 //
  40
  41 // Force out-of-line virtual method.
  42 Pass::~Pass() {
  43   delete Resolver;
  44 }
  45
  46 // Force out-of-line virtual method.
  47 ModulePass::~ModulePass() = default;
  48
  49 Pass *ModulePass::createPrinterPass(raw_ostream &OS,
  50                                     const std::string &Banner) const {
  51   return createPrintModulePass(OS, Banner);
  52 }
  53
  54 PassManagerType ModulePass::getPotentialPassManagerType() const {
  55   return PMT_ModulePassManager;
  56 }
  57
  58 static std::string getDescription(const Module &M) {
  59   return "module (" + M.getName().str() + ")";
  60 }
  61
  62 bool ModulePass::skipModule(Module &M) const {
  63   OptPassGate &Gate = M.getContext().getOptPassGate();
  64   return Gate.isEnabled() && !Gate.shouldRunPass(this, getDescription(M));
  65 }
  66
  67 bool Pass::mustPreserveAnalysisID(char &AID) const {
  68   return Resolver->getAnalysisIfAvailable(&AID, true) != nullptr;
  69 }
  70
  71 // dumpPassStructure - Implement the -debug-pass=Structure option
  72 void Pass::dumpPassStructure(unsigned Offset) {
  73   dbgs().indent(Offset*2) << getPassName() << "\n";
  74 }
  75
  76 /// getPassName - Return a nice clean name for a pass.  This usually
  77 /// implemented in terms of the name that is registered by one of the
  78 /// Registration templates, but can be overloaded directly.
  79 StringRef Pass::getPassName() const {
  80   AnalysisID AID =  getPassID();
  81   const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(AID);
  82   if (PI)
  83     return PI->getPassName();
  84   return "Unnamed pass: implement Pass::getPassName()";
  85 }
  86
  87 void Pass::preparePassManager(PMStack &) {
  88   // By default, don't do anything.
  89 }
  90
  91 PassManagerType Pass::getPotentialPassManagerType() const {
  92   // Default implementation.
  93   return PMT_Unknown;
  94 }
  95
  96 void Pass::getAnalysisUsage(AnalysisUsage &) const {
  97   // By default, no analysis results are used, all are invalidated.
  98 }
  99
 100 void Pass::releaseMemory() {
 101   // By default, don't do anything.
 102 }
 103
 104 void Pass::verifyAnalysis() const {
 105   // By default, don't do anything.
 106 }
 107
 108 void *Pass::getAdjustedAnalysisPointer(AnalysisID AID) {
 109   return this;
 110 }
 111
 112 ImmutablePass *Pass::getAsImmutablePass() {
 113   return nullptr;
 114 }
 115
 116 PMDataManager *Pass::getAsPMDataManager() {
 117   return nullptr;
 118 }
 119
 120 void Pass::setResolver(AnalysisResolver *AR) {
 121   assert(!Resolver && "Resolver is already set");
 122   Resolver = AR;
 123 }
 124
 125 // print - Print out the internal state of the pass.  This is called by Analyze
 126 // to print out the contents of an analysis.  Otherwise it is not necessary to
 127 // implement this method.
 128 void Pass::print(raw_ostream &OS, const Module *) const {
 129   OS << "Pass::print not implemented for pass: '" << getPassName() << "'!\n";
 130 }
 131
 132 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 133 // dump - call print(cerr);
 134 LLVM_DUMP_METHOD void Pass::dump() const {
 135   print(dbgs(), nullptr);
 136 }
 137 #endif
 138
 139 //===----------------------------------------------------------------------===//
 140 // ImmutablePass Implementation
 141 //
 142 // Force out-of-line virtual method.
 143 ImmutablePass::~ImmutablePass() = default;
 144
 145 void ImmutablePass::initializePass() {
 146   // By default, don't do anything.
 147 }
 148
 149 //===----------------------------------------------------------------------===//
 150 // FunctionPass Implementation
 151 //
 152
 153 Pass *FunctionPass::createPrinterPass(raw_ostream &OS,
 154                                       const std::string &Banner) const {
 155   return createPrintFunctionPass(OS, Banner);
 156 }
 157
 158 PassManagerType FunctionPass::getPotentialPassManagerType() const {
 159   return PMT_FunctionPassManager;
 160 }
 161
 162 static std::string getDescription(const Function &F) {
 163   return "function (" + F.getName().str() + ")";
 164 }
 165
 166 bool FunctionPass::skipFunction(const Function &F) const {
 167   OptPassGate &Gate = F.getContext().getOptPassGate();
 168   if (Gate.isEnabled() && !Gate.shouldRunPass(this, getDescription(F)))
 169     return true;
 170
 171   if (F.hasOptNone()) {
 172     LLVM_DEBUG(dbgs() << "Skipping pass '" << getPassName() << "' on function "
 173                       << F.getName() << "\n");
 174     return true;
 175   }
 176   return false;
 177 }
 178
 179 //===----------------------------------------------------------------------===//
 180 // BasicBlockPass Implementation
 181 //
 182
 183 Pass *BasicBlockPass::createPrinterPass(raw_ostream &OS,
 184                                         const std::string &Banner) const {
 185   return createPrintBasicBlockPass(OS, Banner);
 186 }
 187
 188 bool BasicBlockPass::doInitialization(Function &) {
 189   // By default, don't do anything.
 190   return false;
 191 }
 192
 193 bool BasicBlockPass::doFinalization(Function &) {
 194   // By default, don't do anything.
 195   return false;
 196 }
 197
 198 static std::string getDescription(const BasicBlock &BB) {
 199   return "basic block (" + BB.getName().str() + ") in function (" +
 200          BB.getParent()->getName().str() + ")";
 201 }
 202
 203 bool BasicBlockPass::skipBasicBlock(const BasicBlock &BB) const {
 204   const Function *F = BB.getParent();
 205   if (!F)
 206     return false;
 207   OptPassGate &Gate = F->getContext().getOptPassGate();
 208   if (Gate.isEnabled() && !Gate.shouldRunPass(this, getDescription(BB)))
 209     return true;
 210   if (F->hasOptNone()) {
 211     // Report this only once per function.
 212     if (&BB == &F->getEntryBlock())
 213       LLVM_DEBUG(dbgs() << "Skipping pass '" << getPassName()
 214                         << "' on function " << F->getName() << "\n");
 215     return true;
 216   }
 217   return false;
 218 }
 219
 220 PassManagerType BasicBlockPass::getPotentialPassManagerType() const {
 221   return PMT_BasicBlockPassManager;
 222 }
 223
 224 const PassInfo *Pass::lookupPassInfo(const void *TI) {
 225   return PassRegistry::getPassRegistry()->getPassInfo(TI);
 226 }
 227
 228 const PassInfo *Pass::lookupPassInfo(StringRef Arg) {
 229   return PassRegistry::getPassRegistry()->getPassInfo(Arg);
 230 }
 231
 232 Pass *Pass::createPass(AnalysisID ID) {
 233   const PassInfo *PI = PassRegistry::getPassRegistry()->getPassInfo(ID);
 234   if (!PI)
 235     return nullptr;
 236   return PI->createPass();
 237 }
 238
 239 //===----------------------------------------------------------------------===//
 240 //                  Analysis Group Implementation Code
 241 //===----------------------------------------------------------------------===//
 242
 243 // RegisterAGBase implementation
 244
 245 RegisterAGBase::RegisterAGBase(StringRef Name, const void *InterfaceID,
 246                                const void *PassID, bool isDefault)
 247     : PassInfo(Name, InterfaceID) {
 248   PassRegistry::getPassRegistry()->registerAnalysisGroup(InterfaceID, PassID,
 249                                                          *this, isDefault);
 250 }
 251
 252 //===----------------------------------------------------------------------===//
 253 // PassRegistrationListener implementation
 254 //
 255
 256 // enumeratePasses - Iterate over the registered passes, calling the
 257 // passEnumerate callback on each PassInfo object.
 258 void PassRegistrationListener::enumeratePasses() {
 259   PassRegistry::getPassRegistry()->enumerateWith(this);
 260 }
 261
 262 PassNameParser::PassNameParser(cl::Option &O)
 263     : cl::parser<const PassInfo *>(O) {
 264   PassRegistry::getPassRegistry()->addRegistrationListener(this);
 265 }
 266
 267 // This only gets called during static destruction, in which case the
 268 // PassRegistry will have already been destroyed by llvm_shutdown().  So
 269 // attempting to remove the registration listener is an error.
 270 PassNameParser::~PassNameParser() = default;
 271
 272 //===----------------------------------------------------------------------===//
 273 //   AnalysisUsage Class Implementation
 274 //
 275
 276 namespace {
 277
 278 struct GetCFGOnlyPasses : public PassRegistrationListener {
 279   using VectorType = AnalysisUsage::VectorType;
 280
 281   VectorType &CFGOnlyList;
 282
 283   GetCFGOnlyPasses(VectorType &L) : CFGOnlyList(L) {}
 284
 285   void passEnumerate(const PassInfo *P) override {
 286     if (P->isCFGOnlyPass())
 287       CFGOnlyList.push_back(P->getTypeInfo());
 288   }
 289 };
 290
 291 } // end anonymous namespace
 292
 293 // setPreservesCFG - This function should be called to by the pass, iff they do
 294 // not:
 295 //
 296 //  1. Add or remove basic blocks from the function
 297 //  2. Modify terminator instructions in any way.
 298 //
 299 // This function annotates the AnalysisUsage info object to say that analyses
 300 // that only depend on the CFG are preserved by this pass.
 301 void AnalysisUsage::setPreservesCFG() {
 302   // Since this transformation doesn't modify the CFG, it preserves all analyses
 303   // that only depend on the CFG (like dominators, loop info, etc...)
 304   GetCFGOnlyPasses(Preserved).enumeratePasses();
 305 }
 306
 307 AnalysisUsage &AnalysisUsage::addPreserved(StringRef Arg) {
 308   const PassInfo *PI = Pass::lookupPassInfo(Arg);
 309   // If the pass exists, preserve it. Otherwise silently do nothing.
 310   if (PI) Preserved.push_back(PI->getTypeInfo());
 311   return *this;
 312 }
 313
 314 AnalysisUsage &AnalysisUsage::addRequiredID(const void *ID) {
 315   Required.push_back(ID);
 316   return *this;
 317 }
 318
 319 AnalysisUsage &AnalysisUsage::addRequiredID(char &ID) {
 320   Required.push_back(&ID);
 321   return *this;
 322 }
 323
 324 AnalysisUsage &AnalysisUsage::addRequiredTransitiveID(char &ID) {
 325   Required.push_back(&ID);
 326   RequiredTransitive.push_back(&ID);
 327   return *this;
 328 }