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/IR/DebugInfo.h"
16 #include "LLVMContextImpl.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/ADT/SmallPtrSet.h"
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/DIBuilder.h"
21 #include "llvm/IR/DerivedTypes.h"
22 #include "llvm/IR/GVMaterializer.h"
23 #include "llvm/IR/Instructions.h"
24 #include "llvm/IR/IntrinsicInst.h"
25 #include "llvm/IR/Intrinsics.h"
26 #include "llvm/IR/Module.h"
27 #include "llvm/IR/ValueHandle.h"
28 #include "llvm/Support/Debug.h"
29 #include "llvm/Support/Dwarf.h"
30 #include "llvm/Support/raw_ostream.h"
32 using namespace llvm::dwarf;
34 DISubprogram *llvm::getDISubprogram(const MDNode *Scope) {
35 if (auto *LocalScope = dyn_cast_or_null<DILocalScope>(Scope))
36 return LocalScope->getSubprogram();
40 //===----------------------------------------------------------------------===//
41 // DebugInfoFinder implementations.
42 //===----------------------------------------------------------------------===//
44 void DebugInfoFinder::reset() {
53 void DebugInfoFinder::processModule(const Module &M) {
54 for (auto *CU : M.debug_compile_units()) {
56 for (auto DIG : CU->getGlobalVariables()) {
57 if (!addGlobalVariable(DIG))
59 auto *GV = DIG->getVariable();
60 processScope(GV->getScope());
61 processType(GV->getType().resolve());
63 for (auto *ET : CU->getEnumTypes())
65 for (auto *RT : CU->getRetainedTypes())
66 if (auto *T = dyn_cast<DIType>(RT))
69 processSubprogram(cast<DISubprogram>(RT));
70 for (auto *Import : CU->getImportedEntities()) {
71 auto *Entity = Import->getEntity().resolve();
72 if (auto *T = dyn_cast<DIType>(Entity))
74 else if (auto *SP = dyn_cast<DISubprogram>(Entity))
75 processSubprogram(SP);
76 else if (auto *NS = dyn_cast<DINamespace>(Entity))
77 processScope(NS->getScope());
78 else if (auto *M = dyn_cast<DIModule>(Entity))
79 processScope(M->getScope());
82 for (auto &F : M.functions())
83 if (auto *SP = cast_or_null<DISubprogram>(F.getSubprogram()))
84 processSubprogram(SP);
87 void DebugInfoFinder::processLocation(const Module &M, const DILocation *Loc) {
90 processScope(Loc->getScope());
91 processLocation(M, Loc->getInlinedAt());
94 void DebugInfoFinder::processType(DIType *DT) {
97 processScope(DT->getScope().resolve());
98 if (auto *ST = dyn_cast<DISubroutineType>(DT)) {
99 for (DITypeRef Ref : ST->getTypeArray())
100 processType(Ref.resolve());
103 if (auto *DCT = dyn_cast<DICompositeType>(DT)) {
104 processType(DCT->getBaseType().resolve());
105 for (Metadata *D : DCT->getElements()) {
106 if (auto *T = dyn_cast<DIType>(D))
108 else if (auto *SP = dyn_cast<DISubprogram>(D))
109 processSubprogram(SP);
113 if (auto *DDT = dyn_cast<DIDerivedType>(DT)) {
114 processType(DDT->getBaseType().resolve());
118 void DebugInfoFinder::processScope(DIScope *Scope) {
121 if (auto *Ty = dyn_cast<DIType>(Scope)) {
125 if (auto *CU = dyn_cast<DICompileUnit>(Scope)) {
129 if (auto *SP = dyn_cast<DISubprogram>(Scope)) {
130 processSubprogram(SP);
133 if (!addScope(Scope))
135 if (auto *LB = dyn_cast<DILexicalBlockBase>(Scope)) {
136 processScope(LB->getScope());
137 } else if (auto *NS = dyn_cast<DINamespace>(Scope)) {
138 processScope(NS->getScope());
139 } else if (auto *M = dyn_cast<DIModule>(Scope)) {
140 processScope(M->getScope());
144 void DebugInfoFinder::processSubprogram(DISubprogram *SP) {
145 if (!addSubprogram(SP))
147 processScope(SP->getScope().resolve());
148 processType(SP->getType());
149 for (auto *Element : SP->getTemplateParams()) {
150 if (auto *TType = dyn_cast<DITemplateTypeParameter>(Element)) {
151 processType(TType->getType().resolve());
152 } else if (auto *TVal = dyn_cast<DITemplateValueParameter>(Element)) {
153 processType(TVal->getType().resolve());
158 void DebugInfoFinder::processDeclare(const Module &M,
159 const DbgDeclareInst *DDI) {
160 auto *N = dyn_cast<MDNode>(DDI->getVariable());
164 auto *DV = dyn_cast<DILocalVariable>(N);
168 if (!NodesSeen.insert(DV).second)
170 processScope(DV->getScope());
171 processType(DV->getType().resolve());
174 void DebugInfoFinder::processValue(const Module &M, const DbgValueInst *DVI) {
175 auto *N = dyn_cast<MDNode>(DVI->getVariable());
179 auto *DV = dyn_cast<DILocalVariable>(N);
183 if (!NodesSeen.insert(DV).second)
185 processScope(DV->getScope());
186 processType(DV->getType().resolve());
189 bool DebugInfoFinder::addType(DIType *DT) {
193 if (!NodesSeen.insert(DT).second)
196 TYs.push_back(const_cast<DIType *>(DT));
200 bool DebugInfoFinder::addCompileUnit(DICompileUnit *CU) {
203 if (!NodesSeen.insert(CU).second)
210 bool DebugInfoFinder::addGlobalVariable(DIGlobalVariableExpression *DIG) {
211 if (!NodesSeen.insert(DIG).second)
218 bool DebugInfoFinder::addSubprogram(DISubprogram *SP) {
222 if (!NodesSeen.insert(SP).second)
229 bool DebugInfoFinder::addScope(DIScope *Scope) {
232 // FIXME: Ocaml binding generates a scope with no content, we treat it
234 if (Scope->getNumOperands() == 0)
236 if (!NodesSeen.insert(Scope).second)
238 Scopes.push_back(Scope);
242 bool llvm::stripDebugInfo(Function &F) {
243 bool Changed = false;
244 if (F.getSubprogram()) {
246 F.setSubprogram(nullptr);
249 for (BasicBlock &BB : F) {
250 for (auto II = BB.begin(), End = BB.end(); II != End;) {
251 Instruction &I = *II++; // We may delete the instruction, increment now.
252 if (isa<DbgInfoIntrinsic>(&I)) {
257 if (I.getDebugLoc()) {
259 I.setDebugLoc(DebugLoc());
266 bool llvm::StripDebugInfo(Module &M) {
267 bool Changed = false;
269 for (Module::named_metadata_iterator NMI = M.named_metadata_begin(),
270 NME = M.named_metadata_end(); NMI != NME;) {
271 NamedMDNode *NMD = &*NMI;
274 // We're stripping debug info, and without them, coverage information
275 // doesn't quite make sense.
276 if (NMD->getName().startswith("llvm.dbg.") ||
277 NMD->getName() == "llvm.gcov") {
278 NMD->eraseFromParent();
283 for (Function &F : M)
284 Changed |= stripDebugInfo(F);
286 for (auto &GV : M.globals()) {
287 SmallVector<MDNode *, 1> MDs;
288 GV.getMetadata(LLVMContext::MD_dbg, MDs);
290 GV.eraseMetadata(LLVMContext::MD_dbg);
295 if (GVMaterializer *Materializer = M.getMaterializer())
296 Materializer->setStripDebugInfo();
303 /// Helper class to downgrade -g metadata to -gline-tables-only metadata.
304 class DebugTypeInfoRemoval {
305 DenseMap<Metadata *, Metadata *> Replacements;
308 /// The (void)() type.
309 MDNode *EmptySubroutineType;
312 /// Remember what linkage name we originally had before stripping. If we end
313 /// up making two subprograms identical who originally had different linkage
314 /// names, then we need to make one of them distinct, to avoid them getting
315 /// uniqued. Maps the new node to the old linkage name.
316 DenseMap<DISubprogram *, StringRef> NewToLinkageName;
318 // TODO: Remember the distinct subprogram we created for a given linkage name,
319 // so that we can continue to unique whenever possible. Map <newly created
320 // node, old linkage name> to the first (possibly distinct) mdsubprogram
321 // created for that combination. This is not strictly needed for correctness,
322 // but can cut down on the number of MDNodes and let us diff cleanly with the
323 // output of -gline-tables-only.
326 DebugTypeInfoRemoval(LLVMContext &C)
327 : EmptySubroutineType(DISubroutineType::get(C, DINode::FlagZero, 0,
328 MDNode::get(C, {}))) {}
330 Metadata *map(Metadata *M) {
333 auto Replacement = Replacements.find(M);
334 if (Replacement != Replacements.end())
335 return Replacement->second;
339 MDNode *mapNode(Metadata *N) { return dyn_cast_or_null<MDNode>(map(N)); }
341 /// Recursively remap N and all its referenced children. Does a DF post-order
342 /// traversal, so as to remap bottoms up.
343 void traverseAndRemap(MDNode *N) { traverse(N); }
346 // Create a new DISubprogram, to replace the one given.
347 DISubprogram *getReplacementSubprogram(DISubprogram *MDS) {
348 auto *FileAndScope = cast_or_null<DIFile>(map(MDS->getFile()));
349 StringRef LinkageName = MDS->getName().empty() ? MDS->getLinkageName() : "";
350 DISubprogram *Declaration = nullptr;
351 auto *Type = cast_or_null<DISubroutineType>(map(MDS->getType()));
352 DITypeRef ContainingType(map(MDS->getContainingType()));
353 auto *Unit = cast_or_null<DICompileUnit>(map(MDS->getUnit()));
354 auto Variables = nullptr;
355 auto TemplateParams = nullptr;
357 // Make a distinct DISubprogram, for situations that warrent it.
358 auto distinctMDSubprogram = [&]() {
359 return DISubprogram::getDistinct(
360 MDS->getContext(), FileAndScope, MDS->getName(), LinkageName,
361 FileAndScope, MDS->getLine(), Type, MDS->isLocalToUnit(),
362 MDS->isDefinition(), MDS->getScopeLine(), ContainingType,
363 MDS->getVirtuality(), MDS->getVirtualIndex(),
364 MDS->getThisAdjustment(), MDS->getFlags(), MDS->isOptimized(), Unit,
365 TemplateParams, Declaration, Variables);
368 if (MDS->isDistinct())
369 return distinctMDSubprogram();
371 auto *NewMDS = DISubprogram::get(
372 MDS->getContext(), FileAndScope, MDS->getName(), LinkageName,
373 FileAndScope, MDS->getLine(), Type, MDS->isLocalToUnit(),
374 MDS->isDefinition(), MDS->getScopeLine(), ContainingType,
375 MDS->getVirtuality(), MDS->getVirtualIndex(), MDS->getThisAdjustment(),
376 MDS->getFlags(), MDS->isOptimized(), Unit, TemplateParams, Declaration,
379 StringRef OldLinkageName = MDS->getLinkageName();
381 // See if we need to make a distinct one.
382 auto OrigLinkage = NewToLinkageName.find(NewMDS);
383 if (OrigLinkage != NewToLinkageName.end()) {
384 if (OrigLinkage->second == OldLinkageName)
388 // Otherwise, need to make a distinct one.
389 // TODO: Query the map to see if we already have one.
390 return distinctMDSubprogram();
393 NewToLinkageName.insert({NewMDS, MDS->getLinkageName()});
397 /// Create a new compile unit, to replace the one given
398 DICompileUnit *getReplacementCU(DICompileUnit *CU) {
399 // Drop skeleton CUs.
403 auto *File = cast_or_null<DIFile>(map(CU->getFile()));
404 MDTuple *EnumTypes = nullptr;
405 MDTuple *RetainedTypes = nullptr;
406 MDTuple *GlobalVariables = nullptr;
407 MDTuple *ImportedEntities = nullptr;
408 return DICompileUnit::getDistinct(
409 CU->getContext(), CU->getSourceLanguage(), File, CU->getProducer(),
410 CU->isOptimized(), CU->getFlags(), CU->getRuntimeVersion(),
411 CU->getSplitDebugFilename(), DICompileUnit::LineTablesOnly, EnumTypes,
412 RetainedTypes, GlobalVariables, ImportedEntities, CU->getMacros(),
413 CU->getDWOId(), CU->getSplitDebugInlining());
416 DILocation *getReplacementMDLocation(DILocation *MLD) {
417 auto *Scope = map(MLD->getScope());
418 auto *InlinedAt = map(MLD->getInlinedAt());
419 if (MLD->isDistinct())
420 return DILocation::getDistinct(MLD->getContext(), MLD->getLine(),
421 MLD->getColumn(), Scope, InlinedAt);
422 return DILocation::get(MLD->getContext(), MLD->getLine(), MLD->getColumn(),
426 /// Create a new generic MDNode, to replace the one given
427 MDNode *getReplacementMDNode(MDNode *N) {
428 SmallVector<Metadata *, 8> Ops;
429 Ops.reserve(N->getNumOperands());
430 for (auto &I : N->operands())
432 Ops.push_back(map(I));
433 auto *Ret = MDNode::get(N->getContext(), Ops);
437 /// Attempt to re-map N to a newly created node.
438 void remap(MDNode *N) {
439 if (Replacements.count(N))
442 auto doRemap = [&](MDNode *N) -> MDNode * {
445 if (auto *MDSub = dyn_cast<DISubprogram>(N)) {
446 remap(MDSub->getUnit());
447 return getReplacementSubprogram(MDSub);
449 if (isa<DISubroutineType>(N))
450 return EmptySubroutineType;
451 if (auto *CU = dyn_cast<DICompileUnit>(N))
452 return getReplacementCU(CU);
455 if (auto *MDLB = dyn_cast<DILexicalBlockBase>(N))
456 // Remap to our referenced scope (recursively).
457 return mapNode(MDLB->getScope());
458 if (auto *MLD = dyn_cast<DILocation>(N))
459 return getReplacementMDLocation(MLD);
461 // Otherwise, if we see these, just drop them now. Not strictly necessary,
462 // but this speeds things up a little.
466 return getReplacementMDNode(N);
468 Replacements[N] = doRemap(N);
471 /// Do the remapping traversal.
472 void traverse(MDNode *);
475 } // Anonymous namespace.
477 void DebugTypeInfoRemoval::traverse(MDNode *N) {
478 if (!N || Replacements.count(N))
481 // To avoid cycles, as well as for efficiency sake, we will sometimes prune
482 // parts of the graph.
483 auto prune = [](MDNode *Parent, MDNode *Child) {
484 if (auto *MDS = dyn_cast<DISubprogram>(Parent))
485 return Child == MDS->getVariables().get();
489 SmallVector<MDNode *, 16> ToVisit;
490 DenseSet<MDNode *> Opened;
492 // Visit each node starting at N in post order, and map them.
493 ToVisit.push_back(N);
494 while (!ToVisit.empty()) {
495 auto *N = ToVisit.back();
496 if (!Opened.insert(N).second) {
502 for (auto &I : N->operands())
503 if (auto *MDN = dyn_cast_or_null<MDNode>(I))
504 if (!Opened.count(MDN) && !Replacements.count(MDN) && !prune(N, MDN) &&
505 !isa<DICompileUnit>(MDN))
506 ToVisit.push_back(MDN);
510 bool llvm::stripNonLineTableDebugInfo(Module &M) {
511 bool Changed = false;
513 // First off, delete the debug intrinsics.
514 auto RemoveUses = [&](StringRef Name) {
515 if (auto *DbgVal = M.getFunction(Name)) {
516 while (!DbgVal->use_empty())
517 cast<Instruction>(DbgVal->user_back())->eraseFromParent();
518 DbgVal->eraseFromParent();
522 RemoveUses("llvm.dbg.declare");
523 RemoveUses("llvm.dbg.value");
525 // Delete non-CU debug info named metadata nodes.
526 for (auto NMI = M.named_metadata_begin(), NME = M.named_metadata_end();
528 NamedMDNode *NMD = &*NMI;
530 // Specifically keep dbg.cu around.
531 if (NMD->getName() == "llvm.dbg.cu")
535 // Drop all dbg attachments from global variables.
536 for (auto &GV : M.globals())
537 GV.eraseMetadata(LLVMContext::MD_dbg);
539 DebugTypeInfoRemoval Mapper(M.getContext());
540 auto remap = [&](llvm::MDNode *Node) -> llvm::MDNode * {
543 Mapper.traverseAndRemap(Node);
544 auto *NewNode = Mapper.mapNode(Node);
545 Changed |= Node != NewNode;
550 // Rewrite the DebugLocs to be equivalent to what
551 // -gline-tables-only would have created.
553 if (auto *SP = F.getSubprogram()) {
554 Mapper.traverseAndRemap(SP);
555 auto *NewSP = cast<DISubprogram>(Mapper.mapNode(SP));
556 Changed |= SP != NewSP;
557 F.setSubprogram(NewSP);
561 if (I.getDebugLoc() == DebugLoc())
564 // Make a replacement.
565 auto &DL = I.getDebugLoc();
566 auto *Scope = DL.getScope();
567 MDNode *InlinedAt = DL.getInlinedAt();
568 Scope = remap(Scope);
569 InlinedAt = remap(InlinedAt);
571 DebugLoc::get(DL.getLine(), DL.getCol(), Scope, InlinedAt));
576 // Create a new llvm.dbg.cu, which is equivalent to the one
577 // -gline-tables-only would have created.
578 for (auto &NMD : M.getNamedMDList()) {
579 SmallVector<MDNode *, 8> Ops;
580 for (MDNode *Op : NMD.operands())
581 Ops.push_back(remap(Op));
594 unsigned llvm::getDebugMetadataVersionFromModule(const Module &M) {
595 if (auto *Val = mdconst::dyn_extract_or_null<ConstantInt>(
596 M.getModuleFlag("Debug Info Version")))
597 return Val->getZExtValue();