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