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 *ET : CU->getEnumTypes())
98       processType(ET);
99     for (auto *RT : CU->getRetainedTypes())
100       if (auto *T = dyn_cast<DIType>(RT))
101         processType(T);
102       else
103         processSubprogram(cast<DISubprogram>(RT));
104     for (auto *Import : CU->getImportedEntities()) {
105       auto *Entity = Import->getEntity().resolve(TypeIdentifierMap);
106       if (auto *T = dyn_cast<DIType>(Entity))
107         processType(T);
108       else if (auto *SP = dyn_cast<DISubprogram>(Entity))
109         processSubprogram(SP);
110       else if (auto *NS = dyn_cast<DINamespace>(Entity))
111         processScope(NS->getScope());
112       else if (auto *M = dyn_cast<DIModule>(Entity))
113         processScope(M->getScope());
114     }
115   }
116   for (auto &F : M.functions())
117     if (auto *SP = cast_or_null<DISubprogram>(F.getSubprogram()))
118       processSubprogram(SP);
119 }
120 
121 void DebugInfoFinder::processLocation(const Module &M, const DILocation *Loc) {
122   if (!Loc)
123     return;
124   InitializeTypeMap(M);
125   processScope(Loc->getScope());
126   processLocation(M, Loc->getInlinedAt());
127 }
128 
129 void DebugInfoFinder::processType(DIType *DT) {
130   if (!addType(DT))
131     return;
132   processScope(DT->getScope().resolve(TypeIdentifierMap));
133   if (auto *ST = dyn_cast<DISubroutineType>(DT)) {
134     for (DITypeRef Ref : ST->getTypeArray())
135       processType(Ref.resolve(TypeIdentifierMap));
136     return;
137   }
138   if (auto *DCT = dyn_cast<DICompositeType>(DT)) {
139     processType(DCT->getBaseType().resolve(TypeIdentifierMap));
140     for (Metadata *D : DCT->getElements()) {
141       if (auto *T = dyn_cast<DIType>(D))
142         processType(T);
143       else if (auto *SP = dyn_cast<DISubprogram>(D))
144         processSubprogram(SP);
145     }
146     return;
147   }
148   if (auto *DDT = dyn_cast<DIDerivedType>(DT)) {
149     processType(DDT->getBaseType().resolve(TypeIdentifierMap));
150   }
151 }
152 
153 void DebugInfoFinder::processScope(DIScope *Scope) {
154   if (!Scope)
155     return;
156   if (auto *Ty = dyn_cast<DIType>(Scope)) {
157     processType(Ty);
158     return;
159   }
160   if (auto *CU = dyn_cast<DICompileUnit>(Scope)) {
161     addCompileUnit(CU);
162     return;
163   }
164   if (auto *SP = dyn_cast<DISubprogram>(Scope)) {
165     processSubprogram(SP);
166     return;
167   }
168   if (!addScope(Scope))
169     return;
170   if (auto *LB = dyn_cast<DILexicalBlockBase>(Scope)) {
171     processScope(LB->getScope());
172   } else if (auto *NS = dyn_cast<DINamespace>(Scope)) {
173     processScope(NS->getScope());
174   } else if (auto *M = dyn_cast<DIModule>(Scope)) {
175     processScope(M->getScope());
176   }
177 }
178 
179 void DebugInfoFinder::processSubprogram(DISubprogram *SP) {
180   if (!addSubprogram(SP))
181     return;
182   processScope(SP->getScope().resolve(TypeIdentifierMap));
183   processType(SP->getType());
184   for (auto *Element : SP->getTemplateParams()) {
185     if (auto *TType = dyn_cast<DITemplateTypeParameter>(Element)) {
186       processType(TType->getType().resolve(TypeIdentifierMap));
187     } else if (auto *TVal = dyn_cast<DITemplateValueParameter>(Element)) {
188       processType(TVal->getType().resolve(TypeIdentifierMap));
189     }
190   }
191 }
192 
193 void DebugInfoFinder::processDeclare(const Module &M,
194                                      const DbgDeclareInst *DDI) {
195   auto *N = dyn_cast<MDNode>(DDI->getVariable());
196   if (!N)
197     return;
198   InitializeTypeMap(M);
199 
200   auto *DV = dyn_cast<DILocalVariable>(N);
201   if (!DV)
202     return;
203 
204   if (!NodesSeen.insert(DV).second)
205     return;
206   processScope(DV->getScope());
207   processType(DV->getType().resolve(TypeIdentifierMap));
208 }
209 
210 void DebugInfoFinder::processValue(const Module &M, const DbgValueInst *DVI) {
211   auto *N = dyn_cast<MDNode>(DVI->getVariable());
212   if (!N)
213     return;
214   InitializeTypeMap(M);
215 
216   auto *DV = dyn_cast<DILocalVariable>(N);
217   if (!DV)
218     return;
219 
220   if (!NodesSeen.insert(DV).second)
221     return;
222   processScope(DV->getScope());
223   processType(DV->getType().resolve(TypeIdentifierMap));
224 }
225 
226 bool DebugInfoFinder::addType(DIType *DT) {
227   if (!DT)
228     return false;
229 
230   if (!NodesSeen.insert(DT).second)
231     return false;
232 
233   TYs.push_back(const_cast<DIType *>(DT));
234   return true;
235 }
236 
237 bool DebugInfoFinder::addCompileUnit(DICompileUnit *CU) {
238   if (!CU)
239     return false;
240   if (!NodesSeen.insert(CU).second)
241     return false;
242 
243   CUs.push_back(CU);
244   return true;
245 }
246 
247 bool DebugInfoFinder::addGlobalVariable(DIGlobalVariable *DIG) {
248   if (!DIG)
249     return false;
250 
251   if (!NodesSeen.insert(DIG).second)
252     return false;
253 
254   GVs.push_back(DIG);
255   return true;
256 }
257 
258 bool DebugInfoFinder::addSubprogram(DISubprogram *SP) {
259   if (!SP)
260     return false;
261 
262   if (!NodesSeen.insert(SP).second)
263     return false;
264 
265   SPs.push_back(SP);
266   return true;
267 }
268 
269 bool DebugInfoFinder::addScope(DIScope *Scope) {
270   if (!Scope)
271     return false;
272   // FIXME: Ocaml binding generates a scope with no content, we treat it
273   // as null for now.
274   if (Scope->getNumOperands() == 0)
275     return false;
276   if (!NodesSeen.insert(Scope).second)
277     return false;
278   Scopes.push_back(Scope);
279   return true;
280 }
281 
282 bool llvm::stripDebugInfo(Function &F) {
283   bool Changed = false;
284   if (F.getSubprogram()) {
285     Changed = true;
286     F.setSubprogram(nullptr);
287   }
288   for (BasicBlock &BB : F) {
289     for (Instruction &I : BB) {
290       if (I.getDebugLoc()) {
291         Changed = true;
292         I.setDebugLoc(DebugLoc());
293       }
294     }
295   }
296   return Changed;
297 }
298 
299 bool llvm::StripDebugInfo(Module &M) {
300   bool Changed = false;
301 
302   // Remove all of the calls to the debugger intrinsics, and remove them from
303   // the module.
304   if (Function *Declare = M.getFunction("llvm.dbg.declare")) {
305     while (!Declare->use_empty()) {
306       CallInst *CI = cast<CallInst>(Declare->user_back());
307       CI->eraseFromParent();
308     }
309     Declare->eraseFromParent();
310     Changed = true;
311   }
312 
313   if (Function *DbgVal = M.getFunction("llvm.dbg.value")) {
314     while (!DbgVal->use_empty()) {
315       CallInst *CI = cast<CallInst>(DbgVal->user_back());
316       CI->eraseFromParent();
317     }
318     DbgVal->eraseFromParent();
319     Changed = true;
320   }
321 
322   for (Module::named_metadata_iterator NMI = M.named_metadata_begin(),
323          NME = M.named_metadata_end(); NMI != NME;) {
324     NamedMDNode *NMD = &*NMI;
325     ++NMI;
326     if (NMD->getName().startswith("llvm.dbg.")) {
327       NMD->eraseFromParent();
328       Changed = true;
329     }
330   }
331 
332   for (Function &F : M)
333     Changed |= stripDebugInfo(F);
334 
335   if (GVMaterializer *Materializer = M.getMaterializer())
336     Materializer->setStripDebugInfo();
337 
338   return Changed;
339 }
340 
341 unsigned llvm::getDebugMetadataVersionFromModule(const Module &M) {
342   if (auto *Val = mdconst::dyn_extract_or_null<ConstantInt>(
343           M.getModuleFlag("Debug Info Version")))
344     return Val->getZExtValue();
345   return 0;
346 }
347