lib/IR/DebugInfo.cpp

   1 //===--- DebugInfo.cpp - Debug Information Helper Classes -----------------===//
   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 helper classes used to build and interpret debug
  11 // information in LLVM IR form.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/IR/DebugInfo.h"
  16 #include "LLVMContextImpl.h"
  17 #include "llvm/ADT/STLExtras.h"
  18 #include "llvm/ADT/SmallPtrSet.h"
  19 #include "llvm/ADT/SmallString.h"
  20 #include "llvm/Analysis/ValueTracking.h"
  21 #include "llvm/IR/Constants.h"
  22 #include "llvm/IR/DIBuilder.h"
  23 #include "llvm/IR/DerivedTypes.h"
  24 #include "llvm/IR/Instructions.h"
  25 #include "llvm/IR/IntrinsicInst.h"
  26 #include "llvm/IR/Intrinsics.h"
  27 #include "llvm/IR/GVMaterializer.h"
  28 #include "llvm/IR/Module.h"
  29 #include "llvm/IR/ValueHandle.h"
  30 #include "llvm/Support/Debug.h"
  31 #include "llvm/Support/Dwarf.h"
  32 #include "llvm/Support/raw_ostream.h"
  33 using namespace llvm;
  34 using namespace llvm::dwarf;
  35
  36 DISubprogram *llvm::getDISubprogram(const MDNode *Scope) {
  37   if (auto *LocalScope = dyn_cast_or_null<DILocalScope>(Scope))
  38     return LocalScope->getSubprogram();
  39   return nullptr;
  40 }
  41
  42 DISubprogram *llvm::getDISubprogram(const Function *F) {
  43   // We look for the first instr that has a debug annotation leading back to F.
  44   for (auto &BB : *F) {
  45     auto Inst = std::find_if(BB.begin(), BB.end(), [](const Instruction &Inst) {
  46       return Inst.getDebugLoc();
  47     });
  48     if (Inst == BB.end())
  49       continue;
  50     DebugLoc DLoc = Inst->getDebugLoc();
  51     const MDNode *Scope = DLoc.getInlinedAtScope();
  52     auto *Subprogram = getDISubprogram(Scope);
  53     return Subprogram->describes(F) ? Subprogram : nullptr;
  54   }
  55
  56   return nullptr;
  57 }
  58
  59 DITypeIdentifierMap
  60 llvm::generateDITypeIdentifierMap(const NamedMDNode *CU_Nodes) {
  61   DITypeIdentifierMap Map;
  62   for (unsigned CUi = 0, CUe = CU_Nodes->getNumOperands(); CUi != CUe; ++CUi) {
  63     auto *CU = cast<DICompileUnit>(CU_Nodes->getOperand(CUi));
  64     DINodeArray Retain = CU->getRetainedTypes();
  65     for (unsigned Ti = 0, Te = Retain.size(); Ti != Te; ++Ti) {
  66       if (!isa<DICompositeType>(Retain[Ti]))
  67         continue;
  68       auto *Ty = cast<DICompositeType>(Retain[Ti]);
  69       if (MDString *TypeId = Ty->getRawIdentifier()) {
  70         // Definition has priority over declaration.
  71         // Try to insert (TypeId, Ty) to Map.
  72         std::pair<DITypeIdentifierMap::iterator, bool> P =
  73             Map.insert(std::make_pair(TypeId, Ty));
  74         // If TypeId already exists in Map and this is a definition, replace
  75         // whatever we had (declaration or definition) with the definition.
  76         if (!P.second && !Ty->isForwardDecl())
  77           P.first->second = Ty;
  78       }
  79     }
  80   }
  81   return Map;
  82 }
  83
  84 //===----------------------------------------------------------------------===//
  85 // DebugInfoFinder implementations.
  86 //===----------------------------------------------------------------------===//
  87
  88 void DebugInfoFinder::reset() {
  89   CUs.clear();
  90   SPs.clear();
  91   GVs.clear();
  92   TYs.clear();
  93   Scopes.clear();
  94   NodesSeen.clear();
  95   TypeIdentifierMap.clear();
  96   TypeMapInitialized = false;
  97 }
  98
  99 void DebugInfoFinder::InitializeTypeMap(const Module &M) {
 100   if (!TypeMapInitialized)
 101     if (NamedMDNode *CU_Nodes = M.getNamedMetadata("llvm.dbg.cu")) {
 102       TypeIdentifierMap = generateDITypeIdentifierMap(CU_Nodes);
 103       TypeMapInitialized = true;
 104     }
 105 }
 106
 107 void DebugInfoFinder::processModule(const Module &M) {
 108   InitializeTypeMap(M);
 109   if (NamedMDNode *CU_Nodes = M.getNamedMetadata("llvm.dbg.cu")) {
 110     for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
 111       auto *CU = cast<DICompileUnit>(CU_Nodes->getOperand(i));
 112       addCompileUnit(CU);
 113       for (auto *DIG : CU->getGlobalVariables()) {
 114         if (addGlobalVariable(DIG)) {
 115           processScope(DIG->getScope());
 116           processType(DIG->getType().resolve(TypeIdentifierMap));
 117         }
 118       }
 119       for (auto *SP : CU->getSubprograms())
 120         processSubprogram(SP);
 121       for (auto *ET : CU->getEnumTypes())
 122         processType(ET);
 123       for (auto *RT : CU->getRetainedTypes())
 124         processType(RT);
 125       for (auto *Import : CU->getImportedEntities()) {
 126         auto *Entity = Import->getEntity().resolve(TypeIdentifierMap);
 127         if (auto *T = dyn_cast<DIType>(Entity))
 128           processType(T);
 129         else if (auto *SP = dyn_cast<DISubprogram>(Entity))
 130           processSubprogram(SP);
 131         else if (auto *NS = dyn_cast<DINamespace>(Entity))
 132           processScope(NS->getScope());
 133         else if (auto *M = dyn_cast<DIModule>(Entity))
 134           processScope(M->getScope());
 135       }
 136     }
 137   }
 138 }
 139
 140 void DebugInfoFinder::processLocation(const Module &M, const DILocation *Loc) {
 141   if (!Loc)
 142     return;
 143   InitializeTypeMap(M);
 144   processScope(Loc->getScope());
 145   processLocation(M, Loc->getInlinedAt());
 146 }
 147
 148 void DebugInfoFinder::processType(DIType *DT) {
 149   if (!addType(DT))
 150     return;
 151   processScope(DT->getScope().resolve(TypeIdentifierMap));
 152   if (auto *ST = dyn_cast<DISubroutineType>(DT)) {
 153     for (DITypeRef Ref : ST->getTypeArray())
 154       processType(Ref.resolve(TypeIdentifierMap));
 155     return;
 156   }
 157   if (auto *DCT = dyn_cast<DICompositeType>(DT)) {
 158     processType(DCT->getBaseType().resolve(TypeIdentifierMap));
 159     for (Metadata *D : DCT->getElements()) {
 160       if (auto *T = dyn_cast<DIType>(D))
 161         processType(T);
 162       else if (auto *SP = dyn_cast<DISubprogram>(D))
 163         processSubprogram(SP);
 164     }
 165     return;
 166   }
 167   if (auto *DDT = dyn_cast<DIDerivedType>(DT)) {
 168     processType(DDT->getBaseType().resolve(TypeIdentifierMap));
 169   }
 170 }
 171
 172 void DebugInfoFinder::processScope(DIScope *Scope) {
 173   if (!Scope)
 174     return;
 175   if (auto *Ty = dyn_cast<DIType>(Scope)) {
 176     processType(Ty);
 177     return;
 178   }
 179   if (auto *CU = dyn_cast<DICompileUnit>(Scope)) {
 180     addCompileUnit(CU);
 181     return;
 182   }
 183   if (auto *SP = dyn_cast<DISubprogram>(Scope)) {
 184     processSubprogram(SP);
 185     return;
 186   }
 187   if (!addScope(Scope))
 188     return;
 189   if (auto *LB = dyn_cast<DILexicalBlockBase>(Scope)) {
 190     processScope(LB->getScope());
 191   } else if (auto *NS = dyn_cast<DINamespace>(Scope)) {
 192     processScope(NS->getScope());
 193   } else if (auto *M = dyn_cast<DIModule>(Scope)) {
 194     processScope(M->getScope());
 195   }
 196 }
 197
 198 void DebugInfoFinder::processSubprogram(DISubprogram *SP) {
 199   if (!addSubprogram(SP))
 200     return;
 201   processScope(SP->getScope().resolve(TypeIdentifierMap));
 202   processType(SP->getType());
 203   for (auto *Element : SP->getTemplateParams()) {
 204     if (auto *TType = dyn_cast<DITemplateTypeParameter>(Element)) {
 205       processType(TType->getType().resolve(TypeIdentifierMap));
 206     } else if (auto *TVal = dyn_cast<DITemplateValueParameter>(Element)) {
 207       processType(TVal->getType().resolve(TypeIdentifierMap));
 208     }
 209   }
 210 }
 211
 212 void DebugInfoFinder::processDeclare(const Module &M,
 213                                      const DbgDeclareInst *DDI) {
 214   auto *N = dyn_cast<MDNode>(DDI->getVariable());
 215   if (!N)
 216     return;
 217   InitializeTypeMap(M);
 218
 219   auto *DV = dyn_cast<DILocalVariable>(N);
 220   if (!DV)
 221     return;
 222
 223   if (!NodesSeen.insert(DV).second)
 224     return;
 225   processScope(DV->getScope());
 226   processType(DV->getType().resolve(TypeIdentifierMap));
 227 }
 228
 229 void DebugInfoFinder::processValue(const Module &M, const DbgValueInst *DVI) {
 230   auto *N = dyn_cast<MDNode>(DVI->getVariable());
 231   if (!N)
 232     return;
 233   InitializeTypeMap(M);
 234
 235   auto *DV = dyn_cast<DILocalVariable>(N);
 236   if (!DV)
 237     return;
 238
 239   if (!NodesSeen.insert(DV).second)
 240     return;
 241   processScope(DV->getScope());
 242   processType(DV->getType().resolve(TypeIdentifierMap));
 243 }
 244
 245 bool DebugInfoFinder::addType(DIType *DT) {
 246   if (!DT)
 247     return false;
 248
 249   if (!NodesSeen.insert(DT).second)
 250     return false;
 251
 252   TYs.push_back(const_cast<DIType *>(DT));
 253   return true;
 254 }
 255
 256 bool DebugInfoFinder::addCompileUnit(DICompileUnit *CU) {
 257   if (!CU)
 258     return false;
 259   if (!NodesSeen.insert(CU).second)
 260     return false;
 261
 262   CUs.push_back(CU);
 263   return true;
 264 }
 265
 266 bool DebugInfoFinder::addGlobalVariable(DIGlobalVariable *DIG) {
 267   if (!DIG)
 268     return false;
 269
 270   if (!NodesSeen.insert(DIG).second)
 271     return false;
 272
 273   GVs.push_back(DIG);
 274   return true;
 275 }
 276
 277 bool DebugInfoFinder::addSubprogram(DISubprogram *SP) {
 278   if (!SP)
 279     return false;
 280
 281   if (!NodesSeen.insert(SP).second)
 282     return false;
 283
 284   SPs.push_back(SP);
 285   return true;
 286 }
 287
 288 bool DebugInfoFinder::addScope(DIScope *Scope) {
 289   if (!Scope)
 290     return false;
 291   // FIXME: Ocaml binding generates a scope with no content, we treat it
 292   // as null for now.
 293   if (Scope->getNumOperands() == 0)
 294     return false;
 295   if (!NodesSeen.insert(Scope).second)
 296     return false;
 297   Scopes.push_back(Scope);
 298   return true;
 299 }
 300
 301 bool llvm::stripDebugInfo(Function &F) {
 302   bool Changed = false;
 303   if (F.getSubprogram()) {
 304     Changed = true;
 305     F.setSubprogram(nullptr);
 306   }
 307   for (BasicBlock &BB : F) {
 308     for (Instruction &I : BB) {
 309       if (I.getDebugLoc()) {
 310         Changed = true;
 311         I.setDebugLoc(DebugLoc());
 312       }
 313     }
 314   }
 315   return Changed;
 316 }
 317
 318 bool llvm::StripDebugInfo(Module &M) {
 319   bool Changed = false;
 320
 321   // Remove all of the calls to the debugger intrinsics, and remove them from
 322   // the module.
 323   if (Function *Declare = M.getFunction("llvm.dbg.declare")) {
 324     while (!Declare->use_empty()) {
 325       CallInst *CI = cast<CallInst>(Declare->user_back());
 326       CI->eraseFromParent();
 327     }
 328     Declare->eraseFromParent();
 329     Changed = true;
 330   }
 331
 332   if (Function *DbgVal = M.getFunction("llvm.dbg.value")) {
 333     while (!DbgVal->use_empty()) {
 334       CallInst *CI = cast<CallInst>(DbgVal->user_back());
 335       CI->eraseFromParent();
 336     }
 337     DbgVal->eraseFromParent();
 338     Changed = true;
 339   }
 340
 341   for (Module::named_metadata_iterator NMI = M.named_metadata_begin(),
 342          NME = M.named_metadata_end(); NMI != NME;) {
 343     NamedMDNode *NMD = &*NMI;
 344     ++NMI;
 345     if (NMD->getName().startswith("llvm.dbg.")) {
 346       NMD->eraseFromParent();
 347       Changed = true;
 348     }
 349   }
 350
 351   for (Function &F : M)
 352     Changed |= stripDebugInfo(F);
 353
 354   if (GVMaterializer *Materializer = M.getMaterializer())
 355     Materializer->setStripDebugInfo();
 356
 357   return Changed;
 358 }
 359
 360 unsigned llvm::getDebugMetadataVersionFromModule(const Module &M) {
 361   if (auto *Val = mdconst::dyn_extract_or_null<ConstantInt>(
 362           M.getModuleFlag("Debug Info Version")))
 363     return Val->getZExtValue();
 364   return 0;
 365 }