1 //===- DebugInfo.cpp - Debug Information Helper Classes -------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the helper classes used to build and interpret debug
11 // information in LLVM IR form.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/ADT/DenseMap.h"
16 #include "llvm/ADT/DenseSet.h"
17 #include "llvm/ADT/None.h"
18 #include "llvm/ADT/SmallPtrSet.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/ADT/StringRef.h"
21 #include "llvm/IR/BasicBlock.h"
22 #include "llvm/IR/Constants.h"
23 #include "llvm/IR/DebugInfo.h"
24 #include "llvm/IR/DebugInfoMetadata.h"
25 #include "llvm/IR/DebugLoc.h"
26 #include "llvm/IR/Function.h"
27 #include "llvm/IR/GVMaterializer.h"
28 #include "llvm/IR/Instruction.h"
29 #include "llvm/IR/IntrinsicInst.h"
30 #include "llvm/IR/LLVMContext.h"
31 #include "llvm/IR/Metadata.h"
32 #include "llvm/IR/Module.h"
33 #include "llvm/Support/Casting.h"
39 using namespace llvm::dwarf;
41 DISubprogram *llvm::getDISubprogram(const MDNode *Scope) {
42 if (auto *LocalScope = dyn_cast_or_null<DILocalScope>(Scope))
43 return LocalScope->getSubprogram();
47 //===----------------------------------------------------------------------===//
48 // DebugInfoFinder implementations.
49 //===----------------------------------------------------------------------===//
51 void DebugInfoFinder::reset() {
60 void DebugInfoFinder::processModule(const Module &M) {
61 for (auto *CU : M.debug_compile_units()) {
63 for (auto DIG : CU->getGlobalVariables()) {
64 if (!addGlobalVariable(DIG))
66 auto *GV = DIG->getVariable();
67 processScope(GV->getScope());
68 processType(GV->getType().resolve());
70 for (auto *ET : CU->getEnumTypes())
72 for (auto *RT : CU->getRetainedTypes())
73 if (auto *T = dyn_cast<DIType>(RT))
76 processSubprogram(cast<DISubprogram>(RT));
77 for (auto *Import : CU->getImportedEntities()) {
78 auto *Entity = Import->getEntity().resolve();
79 if (auto *T = dyn_cast<DIType>(Entity))
81 else if (auto *SP = dyn_cast<DISubprogram>(Entity))
82 processSubprogram(SP);
83 else if (auto *NS = dyn_cast<DINamespace>(Entity))
84 processScope(NS->getScope());
85 else if (auto *M = dyn_cast<DIModule>(Entity))
86 processScope(M->getScope());
89 for (auto &F : M.functions()) {
90 if (auto *SP = cast_or_null<DISubprogram>(F.getSubprogram()))
91 processSubprogram(SP);
92 // There could be subprograms from inlined functions referenced from
93 // instructions only. Walk the function to find them.
94 for (const BasicBlock &BB : F) {
95 for (const Instruction &I : BB) {
98 processLocation(M, I.getDebugLoc().get());
104 void DebugInfoFinder::processLocation(const Module &M, const DILocation *Loc) {
107 processScope(Loc->getScope());
108 processLocation(M, Loc->getInlinedAt());
111 void DebugInfoFinder::processType(DIType *DT) {
114 processScope(DT->getScope().resolve());
115 if (auto *ST = dyn_cast<DISubroutineType>(DT)) {
116 for (DITypeRef Ref : ST->getTypeArray())
117 processType(Ref.resolve());
120 if (auto *DCT = dyn_cast<DICompositeType>(DT)) {
121 processType(DCT->getBaseType().resolve());
122 for (Metadata *D : DCT->getElements()) {
123 if (auto *T = dyn_cast<DIType>(D))
125 else if (auto *SP = dyn_cast<DISubprogram>(D))
126 processSubprogram(SP);
130 if (auto *DDT = dyn_cast<DIDerivedType>(DT)) {
131 processType(DDT->getBaseType().resolve());
135 void DebugInfoFinder::processScope(DIScope *Scope) {
138 if (auto *Ty = dyn_cast<DIType>(Scope)) {
142 if (auto *CU = dyn_cast<DICompileUnit>(Scope)) {
146 if (auto *SP = dyn_cast<DISubprogram>(Scope)) {
147 processSubprogram(SP);
150 if (!addScope(Scope))
152 if (auto *LB = dyn_cast<DILexicalBlockBase>(Scope)) {
153 processScope(LB->getScope());
154 } else if (auto *NS = dyn_cast<DINamespace>(Scope)) {
155 processScope(NS->getScope());
156 } else if (auto *M = dyn_cast<DIModule>(Scope)) {
157 processScope(M->getScope());
161 void DebugInfoFinder::processSubprogram(DISubprogram *SP) {
162 if (!addSubprogram(SP))
164 processScope(SP->getScope().resolve());
165 processType(SP->getType());
166 for (auto *Element : SP->getTemplateParams()) {
167 if (auto *TType = dyn_cast<DITemplateTypeParameter>(Element)) {
168 processType(TType->getType().resolve());
169 } else if (auto *TVal = dyn_cast<DITemplateValueParameter>(Element)) {
170 processType(TVal->getType().resolve());
175 void DebugInfoFinder::processDeclare(const Module &M,
176 const DbgDeclareInst *DDI) {
177 auto *N = dyn_cast<MDNode>(DDI->getVariable());
181 auto *DV = dyn_cast<DILocalVariable>(N);
185 if (!NodesSeen.insert(DV).second)
187 processScope(DV->getScope());
188 processType(DV->getType().resolve());
191 void DebugInfoFinder::processValue(const Module &M, const DbgValueInst *DVI) {
192 auto *N = dyn_cast<MDNode>(DVI->getVariable());
196 auto *DV = dyn_cast<DILocalVariable>(N);
200 if (!NodesSeen.insert(DV).second)
202 processScope(DV->getScope());
203 processType(DV->getType().resolve());
206 bool DebugInfoFinder::addType(DIType *DT) {
210 if (!NodesSeen.insert(DT).second)
213 TYs.push_back(const_cast<DIType *>(DT));
217 bool DebugInfoFinder::addCompileUnit(DICompileUnit *CU) {
220 if (!NodesSeen.insert(CU).second)
227 bool DebugInfoFinder::addGlobalVariable(DIGlobalVariableExpression *DIG) {
228 if (!NodesSeen.insert(DIG).second)
235 bool DebugInfoFinder::addSubprogram(DISubprogram *SP) {
239 if (!NodesSeen.insert(SP).second)
246 bool DebugInfoFinder::addScope(DIScope *Scope) {
249 // FIXME: Ocaml binding generates a scope with no content, we treat it
251 if (Scope->getNumOperands() == 0)
253 if (!NodesSeen.insert(Scope).second)
255 Scopes.push_back(Scope);
259 static MDNode *stripDebugLocFromLoopID(MDNode *N) {
260 assert(N->op_begin() != N->op_end() && "Missing self reference?");
262 // if there is no debug location, we do not have to rewrite this MDNode.
263 if (std::none_of(N->op_begin() + 1, N->op_end(), [](const MDOperand &Op) {
264 return isa<DILocation>(Op.get());
268 // If there is only the debug location without any actual loop metadata, we
269 // can remove the metadata.
270 if (std::none_of(N->op_begin() + 1, N->op_end(), [](const MDOperand &Op) {
271 return !isa<DILocation>(Op.get());
275 SmallVector<Metadata *, 4> Args;
276 // Reserve operand 0 for loop id self reference.
277 auto TempNode = MDNode::getTemporary(N->getContext(), None);
278 Args.push_back(TempNode.get());
279 // Add all non-debug location operands back.
280 for (auto Op = N->op_begin() + 1; Op != N->op_end(); Op++) {
281 if (!isa<DILocation>(*Op))
285 // Set the first operand to itself.
286 MDNode *LoopID = MDNode::get(N->getContext(), Args);
287 LoopID->replaceOperandWith(0, LoopID);
291 bool llvm::stripDebugInfo(Function &F) {
292 bool Changed = false;
293 if (F.getSubprogram()) {
295 F.setSubprogram(nullptr);
298 DenseMap<MDNode*, MDNode*> LoopIDsMap;
299 for (BasicBlock &BB : F) {
300 for (auto II = BB.begin(), End = BB.end(); II != End;) {
301 Instruction &I = *II++; // We may delete the instruction, increment now.
302 if (isa<DbgInfoIntrinsic>(&I)) {
307 if (I.getDebugLoc()) {
309 I.setDebugLoc(DebugLoc());
313 auto *TermInst = BB.getTerminator();
314 if (auto *LoopID = TermInst->getMetadata(LLVMContext::MD_loop)) {
315 auto *NewLoopID = LoopIDsMap.lookup(LoopID);
317 NewLoopID = LoopIDsMap[LoopID] = stripDebugLocFromLoopID(LoopID);
318 if (NewLoopID != LoopID)
319 TermInst->setMetadata(LLVMContext::MD_loop, NewLoopID);
325 bool llvm::StripDebugInfo(Module &M) {
326 bool Changed = false;
328 for (Module::named_metadata_iterator NMI = M.named_metadata_begin(),
329 NME = M.named_metadata_end(); NMI != NME;) {
330 NamedMDNode *NMD = &*NMI;
333 // We're stripping debug info, and without them, coverage information
334 // doesn't quite make sense.
335 if (NMD->getName().startswith("llvm.dbg.") ||
336 NMD->getName() == "llvm.gcov") {
337 NMD->eraseFromParent();
342 for (Function &F : M)
343 Changed |= stripDebugInfo(F);
345 for (auto &GV : M.globals()) {
346 SmallVector<MDNode *, 1> MDs;
347 GV.getMetadata(LLVMContext::MD_dbg, MDs);
349 GV.eraseMetadata(LLVMContext::MD_dbg);
354 if (GVMaterializer *Materializer = M.getMaterializer())
355 Materializer->setStripDebugInfo();
362 /// Helper class to downgrade -g metadata to -gline-tables-only metadata.
363 class DebugTypeInfoRemoval {
364 DenseMap<Metadata *, Metadata *> Replacements;
367 /// The (void)() type.
368 MDNode *EmptySubroutineType;
371 /// Remember what linkage name we originally had before stripping. If we end
372 /// up making two subprograms identical who originally had different linkage
373 /// names, then we need to make one of them distinct, to avoid them getting
374 /// uniqued. Maps the new node to the old linkage name.
375 DenseMap<DISubprogram *, StringRef> NewToLinkageName;
377 // TODO: Remember the distinct subprogram we created for a given linkage name,
378 // so that we can continue to unique whenever possible. Map <newly created
379 // node, old linkage name> to the first (possibly distinct) mdsubprogram
380 // created for that combination. This is not strictly needed for correctness,
381 // but can cut down on the number of MDNodes and let us diff cleanly with the
382 // output of -gline-tables-only.
385 DebugTypeInfoRemoval(LLVMContext &C)
386 : EmptySubroutineType(DISubroutineType::get(C, DINode::FlagZero, 0,
387 MDNode::get(C, {}))) {}
389 Metadata *map(Metadata *M) {
392 auto Replacement = Replacements.find(M);
393 if (Replacement != Replacements.end())
394 return Replacement->second;
398 MDNode *mapNode(Metadata *N) { return dyn_cast_or_null<MDNode>(map(N)); }
400 /// Recursively remap N and all its referenced children. Does a DF post-order
401 /// traversal, so as to remap bottoms up.
402 void traverseAndRemap(MDNode *N) { traverse(N); }
405 // Create a new DISubprogram, to replace the one given.
406 DISubprogram *getReplacementSubprogram(DISubprogram *MDS) {
407 auto *FileAndScope = cast_or_null<DIFile>(map(MDS->getFile()));
408 StringRef LinkageName = MDS->getName().empty() ? MDS->getLinkageName() : "";
409 DISubprogram *Declaration = nullptr;
410 auto *Type = cast_or_null<DISubroutineType>(map(MDS->getType()));
411 DITypeRef ContainingType(map(MDS->getContainingType()));
412 auto *Unit = cast_or_null<DICompileUnit>(map(MDS->getUnit()));
413 auto Variables = nullptr;
414 auto TemplateParams = nullptr;
416 // Make a distinct DISubprogram, for situations that warrent it.
417 auto distinctMDSubprogram = [&]() {
418 return DISubprogram::getDistinct(
419 MDS->getContext(), FileAndScope, MDS->getName(), LinkageName,
420 FileAndScope, MDS->getLine(), Type, MDS->isLocalToUnit(),
421 MDS->isDefinition(), MDS->getScopeLine(), ContainingType,
422 MDS->getVirtuality(), MDS->getVirtualIndex(),
423 MDS->getThisAdjustment(), MDS->getFlags(), MDS->isOptimized(), Unit,
424 TemplateParams, Declaration, Variables);
427 if (MDS->isDistinct())
428 return distinctMDSubprogram();
430 auto *NewMDS = DISubprogram::get(
431 MDS->getContext(), FileAndScope, MDS->getName(), LinkageName,
432 FileAndScope, MDS->getLine(), Type, MDS->isLocalToUnit(),
433 MDS->isDefinition(), MDS->getScopeLine(), ContainingType,
434 MDS->getVirtuality(), MDS->getVirtualIndex(), MDS->getThisAdjustment(),
435 MDS->getFlags(), MDS->isOptimized(), Unit, TemplateParams, Declaration,
438 StringRef OldLinkageName = MDS->getLinkageName();
440 // See if we need to make a distinct one.
441 auto OrigLinkage = NewToLinkageName.find(NewMDS);
442 if (OrigLinkage != NewToLinkageName.end()) {
443 if (OrigLinkage->second == OldLinkageName)
447 // Otherwise, need to make a distinct one.
448 // TODO: Query the map to see if we already have one.
449 return distinctMDSubprogram();
452 NewToLinkageName.insert({NewMDS, MDS->getLinkageName()});
456 /// Create a new compile unit, to replace the one given
457 DICompileUnit *getReplacementCU(DICompileUnit *CU) {
458 // Drop skeleton CUs.
462 auto *File = cast_or_null<DIFile>(map(CU->getFile()));
463 MDTuple *EnumTypes = nullptr;
464 MDTuple *RetainedTypes = nullptr;
465 MDTuple *GlobalVariables = nullptr;
466 MDTuple *ImportedEntities = nullptr;
467 return DICompileUnit::getDistinct(
468 CU->getContext(), CU->getSourceLanguage(), File, CU->getProducer(),
469 CU->isOptimized(), CU->getFlags(), CU->getRuntimeVersion(),
470 CU->getSplitDebugFilename(), DICompileUnit::LineTablesOnly, EnumTypes,
471 RetainedTypes, GlobalVariables, ImportedEntities, CU->getMacros(),
472 CU->getDWOId(), CU->getSplitDebugInlining(),
473 CU->getDebugInfoForProfiling());
476 DILocation *getReplacementMDLocation(DILocation *MLD) {
477 auto *Scope = map(MLD->getScope());
478 auto *InlinedAt = map(MLD->getInlinedAt());
479 if (MLD->isDistinct())
480 return DILocation::getDistinct(MLD->getContext(), MLD->getLine(),
481 MLD->getColumn(), Scope, InlinedAt);
482 return DILocation::get(MLD->getContext(), MLD->getLine(), MLD->getColumn(),
486 /// Create a new generic MDNode, to replace the one given
487 MDNode *getReplacementMDNode(MDNode *N) {
488 SmallVector<Metadata *, 8> Ops;
489 Ops.reserve(N->getNumOperands());
490 for (auto &I : N->operands())
492 Ops.push_back(map(I));
493 auto *Ret = MDNode::get(N->getContext(), Ops);
497 /// Attempt to re-map N to a newly created node.
498 void remap(MDNode *N) {
499 if (Replacements.count(N))
502 auto doRemap = [&](MDNode *N) -> MDNode * {
505 if (auto *MDSub = dyn_cast<DISubprogram>(N)) {
506 remap(MDSub->getUnit());
507 return getReplacementSubprogram(MDSub);
509 if (isa<DISubroutineType>(N))
510 return EmptySubroutineType;
511 if (auto *CU = dyn_cast<DICompileUnit>(N))
512 return getReplacementCU(CU);
515 if (auto *MDLB = dyn_cast<DILexicalBlockBase>(N))
516 // Remap to our referenced scope (recursively).
517 return mapNode(MDLB->getScope());
518 if (auto *MLD = dyn_cast<DILocation>(N))
519 return getReplacementMDLocation(MLD);
521 // Otherwise, if we see these, just drop them now. Not strictly necessary,
522 // but this speeds things up a little.
526 return getReplacementMDNode(N);
528 Replacements[N] = doRemap(N);
531 /// Do the remapping traversal.
532 void traverse(MDNode *);
535 } // end anonymous namespace
537 void DebugTypeInfoRemoval::traverse(MDNode *N) {
538 if (!N || Replacements.count(N))
541 // To avoid cycles, as well as for efficiency sake, we will sometimes prune
542 // parts of the graph.
543 auto prune = [](MDNode *Parent, MDNode *Child) {
544 if (auto *MDS = dyn_cast<DISubprogram>(Parent))
545 return Child == MDS->getVariables().get();
549 SmallVector<MDNode *, 16> ToVisit;
550 DenseSet<MDNode *> Opened;
552 // Visit each node starting at N in post order, and map them.
553 ToVisit.push_back(N);
554 while (!ToVisit.empty()) {
555 auto *N = ToVisit.back();
556 if (!Opened.insert(N).second) {
562 for (auto &I : N->operands())
563 if (auto *MDN = dyn_cast_or_null<MDNode>(I))
564 if (!Opened.count(MDN) && !Replacements.count(MDN) && !prune(N, MDN) &&
565 !isa<DICompileUnit>(MDN))
566 ToVisit.push_back(MDN);
570 bool llvm::stripNonLineTableDebugInfo(Module &M) {
571 bool Changed = false;
573 // First off, delete the debug intrinsics.
574 auto RemoveUses = [&](StringRef Name) {
575 if (auto *DbgVal = M.getFunction(Name)) {
576 while (!DbgVal->use_empty())
577 cast<Instruction>(DbgVal->user_back())->eraseFromParent();
578 DbgVal->eraseFromParent();
582 RemoveUses("llvm.dbg.declare");
583 RemoveUses("llvm.dbg.value");
585 // Delete non-CU debug info named metadata nodes.
586 for (auto NMI = M.named_metadata_begin(), NME = M.named_metadata_end();
588 NamedMDNode *NMD = &*NMI;
590 // Specifically keep dbg.cu around.
591 if (NMD->getName() == "llvm.dbg.cu")
595 // Drop all dbg attachments from global variables.
596 for (auto &GV : M.globals())
597 GV.eraseMetadata(LLVMContext::MD_dbg);
599 DebugTypeInfoRemoval Mapper(M.getContext());
600 auto remap = [&](MDNode *Node) -> MDNode * {
603 Mapper.traverseAndRemap(Node);
604 auto *NewNode = Mapper.mapNode(Node);
605 Changed |= Node != NewNode;
610 // Rewrite the DebugLocs to be equivalent to what
611 // -gline-tables-only would have created.
613 if (auto *SP = F.getSubprogram()) {
614 Mapper.traverseAndRemap(SP);
615 auto *NewSP = cast<DISubprogram>(Mapper.mapNode(SP));
616 Changed |= SP != NewSP;
617 F.setSubprogram(NewSP);
621 auto remapDebugLoc = [&](DebugLoc DL) -> DebugLoc {
622 auto *Scope = DL.getScope();
623 MDNode *InlinedAt = DL.getInlinedAt();
624 Scope = remap(Scope);
625 InlinedAt = remap(InlinedAt);
626 return DebugLoc::get(DL.getLine(), DL.getCol(), Scope, InlinedAt);
629 if (I.getDebugLoc() != DebugLoc())
630 I.setDebugLoc(remapDebugLoc(I.getDebugLoc()));
632 // Remap DILocations in untyped MDNodes (e.g., llvm.loop).
633 SmallVector<std::pair<unsigned, MDNode *>, 2> MDs;
634 I.getAllMetadata(MDs);
635 for (auto Attachment : MDs)
636 if (auto *T = dyn_cast_or_null<MDTuple>(Attachment.second))
637 for (unsigned N = 0; N < T->getNumOperands(); ++N)
638 if (auto *Loc = dyn_cast_or_null<DILocation>(T->getOperand(N)))
639 if (Loc != DebugLoc())
640 T->replaceOperandWith(N, remapDebugLoc(Loc));
645 // Create a new llvm.dbg.cu, which is equivalent to the one
646 // -gline-tables-only would have created.
647 for (auto &NMD : M.getNamedMDList()) {
648 SmallVector<MDNode *, 8> Ops;
649 for (MDNode *Op : NMD.operands())
650 Ops.push_back(remap(Op));
663 unsigned llvm::getDebugMetadataVersionFromModule(const Module &M) {
664 if (auto *Val = mdconst::dyn_extract_or_null<ConstantInt>(
665 M.getModuleFlag("Debug Info Version")))
666 return Val->getZExtValue();