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