CGDebugInfo.cpp revision 2e1cd4264d363ca869bf37ef160902f211d21b8c 
1//===--- CGDebugInfo.cpp - Emit Debug Information for a Module ------------===//
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 coordinates the debug information generation while generating code.
11//
12//===----------------------------------------------------------------------===//
13
14#include "CGDebugInfo.h"
15#include "CodeGenModule.h"
16#include "clang/AST/ASTContext.h"
17#include "clang/AST/Decl.h"
18#include "clang/AST/Expr.h"
19#include "clang/AST/RecordLayout.h"
20#include "clang/Basic/SourceManager.h"
21#include "clang/Basic/FileManager.h"
22#include "llvm/Constants.h"
23#include "llvm/DerivedTypes.h"
24#include "llvm/Instructions.h"
25#include "llvm/Intrinsics.h"
26#include "llvm/Module.h"
27#include "llvm/ADT/StringExtras.h"
28#include "llvm/ADT/SmallVector.h"
29#include "llvm/Support/Dwarf.h"
30#include "llvm/Target/TargetMachine.h"
31using namespace clang;
32using namespace clang::CodeGen;
33
34CGDebugInfo::CGDebugInfo(CodeGenModule *m)
35  : M(m), DebugFactory(M->getModule()) {
36}
37
38CGDebugInfo::~CGDebugInfo() {
39  assert(RegionStack.empty() && "Region stack mismatch, stack not empty!");
40}
41
42void CGDebugInfo::setLocation(SourceLocation Loc) {
43  if (Loc.isValid())
44    CurLoc = M->getContext().getSourceManager().getLogicalLoc(Loc);
45}
46
47/// getOrCreateCompileUnit - Get the compile unit from the cache or create a new
48/// one if necessary. This returns null for invalid source locations.
49llvm::DICompileUnit CGDebugInfo::getOrCreateCompileUnit(SourceLocation Loc) {
50  if (Loc.isInvalid())
51    return llvm::DICompileUnit();
52
53  SourceManager &SM = M->getContext().getSourceManager();
54  const FileEntry *FE = SM.getFileEntryForLoc(Loc);
55  if (FE == 0) return llvm::DICompileUnit();
56
57  // See if this compile unit has been used before.
58  llvm::DICompileUnit &Unit = CompileUnitCache[FE];
59  if (!Unit.isNull()) return Unit;
60
61  // Get source file information.
62  const char *FileName = FE->getName();
63  const char *DirName = FE->getDir()->getName();
64
65  // Create new compile unit.
66  // FIXME: Handle other language IDs as well.
67  // FIXME: Do not know how to get clang version yet.
68  return Unit = DebugFactory.CreateCompileUnit(llvm::dwarf::DW_LANG_C89,
69                                               FileName, DirName, "clang");
70}
71
72/// getOrCreateBuiltinType - Get the Basic type from the cache or create a new
73/// one if necessary.
74llvm::DIType CGDebugInfo::CreateType(const BuiltinType *BT,
75                                     llvm::DICompileUnit Unit){
76  unsigned Encoding = 0;
77  switch (BT->getKind()) {
78  default:
79  case BuiltinType::Void:
80    return llvm::DIType();
81  case BuiltinType::UChar:
82  case BuiltinType::Char_U: Encoding = llvm::dwarf::DW_ATE_unsigned_char; break;
83  case BuiltinType::Char_S:
84  case BuiltinType::SChar: Encoding = llvm::dwarf::DW_ATE_signed_char; break;
85  case BuiltinType::UShort:
86  case BuiltinType::UInt:
87  case BuiltinType::ULong:
88  case BuiltinType::ULongLong: Encoding = llvm::dwarf::DW_ATE_unsigned; break;
89  case BuiltinType::Short:
90  case BuiltinType::Int:
91  case BuiltinType::Long:
92  case BuiltinType::LongLong:  Encoding = llvm::dwarf::DW_ATE_signed; break;
93  case BuiltinType::Bool:      Encoding = llvm::dwarf::DW_ATE_boolean; break;
94  case BuiltinType::Float:
95  case BuiltinType::Double:    Encoding = llvm::dwarf::DW_ATE_float; break;
96  }
97  // Bit size, align and offset of the type.
98  uint64_t Size = M->getContext().getTypeSize(BT);
99  uint64_t Align = M->getContext().getTypeAlign(BT);
100  uint64_t Offset = 0;
101
102  return DebugFactory.CreateBasicType(Unit, BT->getName(), Unit, 0, Size, Align,
103                                      Offset, /*flags*/ 0, Encoding);
104}
105
106/// getOrCreateCVRType - Get the CVR qualified type from the cache or create
107/// a new one if necessary.
108llvm::DIType CGDebugInfo::CreateCVRType(QualType Ty, llvm::DICompileUnit Unit) {
109  // We will create one Derived type for one qualifier and recurse to handle any
110  // additional ones.
111  llvm::DIType FromTy;
112  unsigned Tag;
113  if (Ty.isConstQualified()) {
114    Tag = llvm::dwarf::DW_TAG_const_type;
115    Ty.removeConst();
116    FromTy = getOrCreateType(Ty, Unit);
117  } else if (Ty.isVolatileQualified()) {
118    Tag = llvm::dwarf::DW_TAG_volatile_type;
119    Ty.removeVolatile();
120    FromTy = getOrCreateType(Ty, Unit);
121  } else {
122    assert(Ty.isRestrictQualified() && "Unknown type qualifier for debug info");
123    Tag = llvm::dwarf::DW_TAG_restrict_type;
124    Ty.removeRestrict();
125    FromTy = getOrCreateType(Ty, Unit);
126  }
127
128  // No need to fill in the Name, Line, Size, Alignment, Offset in case of
129  // CVR derived types.
130  return DebugFactory.CreateDerivedType(Tag, Unit, "", llvm::DICompileUnit(),
131                                        0, 0, 0, 0, 0, FromTy);
132}
133
134llvm::DIType CGDebugInfo::CreateType(const PointerType *Ty,
135                                     llvm::DICompileUnit Unit) {
136  llvm::DIType EltTy = getOrCreateType(Ty->getPointeeType(), Unit);
137
138  // Bit size, align and offset of the type.
139  uint64_t Size = M->getContext().getTypeSize(Ty);
140  uint64_t Align = M->getContext().getTypeAlign(Ty);
141
142  return DebugFactory.CreateDerivedType(llvm::dwarf::DW_TAG_pointer_type, Unit,
143                                        "", llvm::DICompileUnit(),
144                                        0, Size, Align, 0, 0, EltTy);
145}
146
147llvm::DIType CGDebugInfo::CreateType(const TypedefType *Ty,
148                                     llvm::DICompileUnit Unit) {
149  // Typedefs are derived from some other type.  If we have a typedef of a
150  // typedef, make sure to emit the whole chain.
151  llvm::DIType Src = getOrCreateType(Ty->getDecl()->getUnderlyingType(), Unit);
152
153  // We don't set size information, but do specify where the typedef was
154  // declared.
155  const char *TyName = Ty->getDecl()->getIdentifierName();
156  SourceLocation DefLoc = Ty->getDecl()->getLocation();
157  llvm::DICompileUnit DefUnit = getOrCreateCompileUnit(DefLoc);
158
159  SourceManager &SM = M->getContext().getSourceManager();
160  uint64_t Line = SM.getLogicalLineNumber(DefLoc);
161
162  return DebugFactory.CreateDerivedType(llvm::dwarf::DW_TAG_typedef, Unit,
163                                        TyName, DefUnit, Line, 0, 0, 0, 0, Src);
164}
165
166llvm::DIType CGDebugInfo::CreateType(const FunctionType *Ty,
167                                     llvm::DICompileUnit Unit) {
168  llvm::SmallVector<llvm::DIDescriptor, 16> EltTys;
169
170  // Add the result type at least.
171  EltTys.push_back(getOrCreateType(Ty->getResultType(), Unit));
172
173  // Set up remainder of arguments if there is a prototype.
174  // FIXME: IF NOT, HOW IS THIS REPRESENTED?  llvm-gcc doesn't represent '...'!
175  if (const FunctionTypeProto *FTP = dyn_cast<FunctionTypeProto>(Ty)) {
176    for (unsigned i = 0, e = FTP->getNumArgs(); i != e; ++i)
177      EltTys.push_back(getOrCreateType(FTP->getArgType(i), Unit));
178  } else {
179    // FIXME: Handle () case in C.  llvm-gcc doesn't do it either.
180  }
181
182  llvm::DIArray EltTypeArray =
183    DebugFactory.GetOrCreateArray(&EltTys[0], EltTys.size());
184
185  return DebugFactory.CreateCompositeType(llvm::dwarf::DW_TAG_subroutine_type,
186                                          Unit, "", llvm::DICompileUnit(),
187                                          0, 0, 0, 0, 0,
188                                          llvm::DIType(), EltTypeArray);
189}
190
191/// getOrCreateRecordType - get structure or union type.
192llvm::DIType CGDebugInfo::CreateType(const RecordType *Ty,
193                                     llvm::DICompileUnit Unit) {
194  const RecordDecl *Decl = Ty->getDecl();
195
196  unsigned Tag;
197  if (Decl->isStruct())
198    Tag = llvm::dwarf::DW_TAG_structure_type;
199  else if (Decl->isUnion())
200    Tag = llvm::dwarf::DW_TAG_union_type;
201  else {
202    assert(Decl->isClass() && "Unknown RecordType!");
203    Tag = llvm::dwarf::DW_TAG_class_type;
204  }
205
206  SourceManager &SM = M->getContext().getSourceManager();
207
208  // Get overall information about the record type for the debug info.
209  const char *Name = Decl->getIdentifierName();
210  if (Name == 0) Name = "";
211
212  llvm::DICompileUnit DefUnit = getOrCreateCompileUnit(Decl->getLocation());
213  uint64_t Line = SM.getLogicalLineNumber(Decl->getLocation());
214
215
216  // Records and classes and unions can all be recursive.  To handle them, we
217  // first generate a debug descriptor for the struct as a forward declaration.
218  // Then (if it is a definition) we go through and get debug info for all of
219  // its members.  Finally, we create a descriptor for the complete type (which
220  // may refer to the forward decl if the struct is recursive) and replace all
221  // uses of the forward declaration with the final definition.
222  llvm::DIType FwdDecl =
223    DebugFactory.CreateCompositeType(Tag, Unit, Name, DefUnit, Line, 0, 0, 0, 0,
224                                     llvm::DIType(), llvm::DIArray());
225
226  // If this is just a forward declaration, return it.
227  if (!Decl->getDefinition(M->getContext()))
228    return FwdDecl;
229
230  // Otherwise, insert it into the TypeCache so that recursive uses will find
231  // it.
232  TypeCache[QualType(Ty, 0).getAsOpaquePtr()] = FwdDecl;
233
234  // Convert all the elements.
235  llvm::SmallVector<llvm::DIDescriptor, 16> EltTys;
236
237  const ASTRecordLayout &RL = M->getContext().getASTRecordLayout(Decl);
238
239  unsigned FieldNo = 0;
240  for (RecordDecl::field_const_iterator I = Decl->field_begin(),
241       E = Decl->field_end(); I != E; ++I, ++FieldNo) {
242    FieldDecl *Field = *I;
243    llvm::DIType FieldTy = getOrCreateType(Field->getType(), Unit);
244
245    const char *FieldName = Field->getIdentifierName();
246    if (FieldName == 0) FieldName = "";
247
248    // Get the location for the field.
249    SourceLocation FieldDefLoc = Field->getLocation();
250    llvm::DICompileUnit FieldDefUnit = getOrCreateCompileUnit(FieldDefLoc);
251    uint64_t FieldLine = SM.getLogicalLineNumber(FieldDefLoc);
252
253    // Bit size, align and offset of the type.
254    uint64_t FieldSize = M->getContext().getTypeSize(Ty);
255    uint64_t FieldAlign = M->getContext().getTypeAlign(Ty);
256    uint64_t FieldOffset = RL.getFieldOffset(FieldNo);
257
258    // Create a DW_TAG_member node to remember the offset of this field in the
259    // struct.  FIXME: This is an absolutely insane way to capture this
260    // information.  When we gut debug info, this should be fixed.
261    FieldTy = DebugFactory.CreateDerivedType(llvm::dwarf::DW_TAG_member, Unit,
262                                             FieldName, FieldDefUnit,
263                                             FieldLine, FieldSize, FieldAlign,
264                                             FieldOffset, 0, FieldTy);
265    EltTys.push_back(FieldTy);
266  }
267
268  llvm::DIArray Elements =
269    DebugFactory.GetOrCreateArray(&EltTys[0], EltTys.size());
270
271  // Bit size, align and offset of the type.
272  uint64_t Size = M->getContext().getTypeSize(Ty);
273  uint64_t Align = M->getContext().getTypeAlign(Ty);
274
275  llvm::DIType RealDecl =
276    DebugFactory.CreateCompositeType(Tag, Unit, Name, DefUnit, Line, Size,
277                                     Align, 0, 0, llvm::DIType(), Elements);
278
279  // Now that we have a real decl for the struct, replace anything using the
280  // old decl with the new one.  This will recursively update the debug info.
281  FwdDecl.getGV()->replaceAllUsesWith(RealDecl.getGV());
282  FwdDecl.getGV()->eraseFromParent();
283
284  return RealDecl;
285}
286
287llvm::DIType CGDebugInfo::CreateType(const EnumType *Ty,
288                                     llvm::DICompileUnit Unit) {
289  EnumDecl *Decl = Ty->getDecl();
290
291  llvm::SmallVector<llvm::DIDescriptor, 32> Enumerators;
292
293  // Create DIEnumerator elements for each enumerator.
294  for (EnumConstantDecl *Elt = Decl->getEnumConstantList(); Elt;
295       Elt = dyn_cast_or_null<EnumConstantDecl>(Elt->getNextDeclarator())) {
296    Enumerators.push_back(DebugFactory.CreateEnumerator(Elt->getName(),
297                                            Elt->getInitVal().getZExtValue()));
298  }
299
300  // Return a CompositeType for the enum itself.
301  llvm::DIArray EltArray =
302    DebugFactory.GetOrCreateArray(&Enumerators[0], Enumerators.size());
303
304  const char *EnumName
305    = Decl->getIdentifierName() ? Decl->getIdentifierName() : "";
306  SourceLocation DefLoc = Decl->getLocation();
307  llvm::DICompileUnit DefUnit = getOrCreateCompileUnit(DefLoc);
308  SourceManager &SM = M->getContext().getSourceManager();
309  uint64_t Line = SM.getLogicalLineNumber(DefLoc);
310
311  // Size and align of the type.
312  uint64_t Size = M->getContext().getTypeSize(Ty);
313  uint64_t Align = M->getContext().getTypeAlign(Ty);
314
315  return DebugFactory.CreateCompositeType(llvm::dwarf::DW_TAG_enumeration_type,
316                                          Unit, EnumName, DefUnit, Line,
317                                          Size, Align, 0, 0,
318                                          llvm::DIType(), EltArray);
319}
320
321llvm::DIType CGDebugInfo::CreateType(const TagType *Ty,
322                                     llvm::DICompileUnit Unit) {
323  if (const RecordType *RT = dyn_cast<RecordType>(Ty))
324    return CreateType(RT, Unit);
325  else if (const EnumType *ET = dyn_cast<EnumType>(Ty))
326    return CreateType(ET, Unit);
327
328  return llvm::DIType();
329}
330
331llvm::DIType CGDebugInfo::CreateType(const ArrayType *Ty,
332                                     llvm::DICompileUnit Unit) {
333  // Size and align of the whole array, not the element type.
334  uint64_t Size = M->getContext().getTypeSize(Ty);
335  uint64_t Align = M->getContext().getTypeAlign(Ty);
336
337  // Add the dimensions of the array.  FIXME: This loses CV qualifiers from
338  // interior arrays, do we care?  Why aren't nested arrays represented the
339  // obvious/recursive way?
340  llvm::SmallVector<llvm::DIDescriptor, 8> Subscripts;
341  QualType EltTy(Ty, 0);
342  while ((Ty = dyn_cast<ArrayType>(EltTy))) {
343    uint64_t Upper = 0;
344    if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(Ty))
345      Upper = CAT->getSize().getZExtValue() - 1;
346    // FIXME: Verify this is right for VLAs.
347    Subscripts.push_back(DebugFactory.GetOrCreateSubrange(0, Upper));
348    EltTy = Ty->getElementType();
349  }
350
351  llvm::DIArray SubscriptArray =
352    DebugFactory.GetOrCreateArray(&Subscripts[0], Subscripts.size());
353
354  return DebugFactory.CreateCompositeType(llvm::dwarf::DW_TAG_array_type,
355                                          Unit, "", llvm::DICompileUnit(),
356                                          0, Size, Align, 0, 0,
357                                          getOrCreateType(EltTy, Unit),
358                                          SubscriptArray);
359}
360
361
362/// getOrCreateType - Get the type from the cache or create a new
363/// one if necessary.
364llvm::DIType CGDebugInfo::getOrCreateType(QualType Ty,
365                                          llvm::DICompileUnit Unit) {
366  if (Ty.isNull())
367    return llvm::DIType();
368
369  // Check to see if the compile unit already has created this type.
370  llvm::DIType &Slot = TypeCache[Ty.getAsOpaquePtr()];
371  if (!Slot.isNull()) return Slot;
372
373  // Handle CVR qualifiers, which recursively handles what they refer to.
374  if (Ty.getCVRQualifiers())
375    return Slot = CreateCVRType(Ty, Unit);
376
377  // Work out details of type.
378  switch (Ty->getTypeClass()) {
379  case Type::Complex:
380  case Type::Reference:
381  case Type::Vector:
382  case Type::ExtVector:
383  case Type::ASQual:
384  case Type::ObjCInterface:
385  case Type::ObjCQualifiedInterface:
386  case Type::ObjCQualifiedId:
387  default:
388    return llvm::DIType();
389
390  case Type::Builtin: Slot = CreateType(cast<BuiltinType>(Ty), Unit); break;
391  case Type::Pointer: Slot = CreateType(cast<PointerType>(Ty), Unit); break;
392  case Type::TypeName: Slot = CreateType(cast<TypedefType>(Ty), Unit); break;
393  case Type::Tagged: Slot = CreateType(cast<TagType>(Ty), Unit); break;
394  case Type::FunctionProto:
395  case Type::FunctionNoProto:
396    return Slot = CreateType(cast<FunctionType>(Ty), Unit);
397
398  case Type::ConstantArray:
399  case Type::VariableArray:
400  case Type::IncompleteArray:
401    return Slot = CreateType(cast<ArrayType>(Ty), Unit);
402  case Type::TypeOfExp:
403    return Slot = getOrCreateType(cast<TypeOfExpr>(Ty)->getUnderlyingExpr()
404                                  ->getType(), Unit);
405  case Type::TypeOfTyp:
406    return Slot = getOrCreateType(cast<TypeOfType>(Ty)->getUnderlyingType(),
407                                  Unit);
408  }
409
410  return Slot;
411}
412
413/// EmitFunctionStart - Constructs the debug code for entering a function -
414/// "llvm.dbg.func.start.".
415void CGDebugInfo::EmitFunctionStart(const char *Name, QualType ReturnType,
416                                    llvm::Function *Fn,
417                                    CGBuilderTy &Builder) {
418  // FIXME: Why is this using CurLoc???
419  llvm::DICompileUnit Unit = getOrCreateCompileUnit(CurLoc);
420  SourceManager &SM = M->getContext().getSourceManager();
421  uint64_t LineNo = SM.getLogicalLineNumber(CurLoc);
422
423  llvm::DISubprogram SP =
424    DebugFactory.CreateSubprogram(Unit, Name, Name, "", Unit, LineNo,
425                                  getOrCreateType(ReturnType, Unit),
426                                  Fn->hasInternalLinkage(), true/*definition*/);
427
428  DebugFactory.InsertSubprogramStart(SP, Builder.GetInsertBlock());
429
430  // Push function on region stack.
431  RegionStack.push_back(SP);
432}
433
434
435void CGDebugInfo::EmitStopPoint(llvm::Function *Fn, CGBuilderTy &Builder) {
436  if (CurLoc.isInvalid() || CurLoc.isMacroID()) return;
437
438  // Don't bother if things are the same as last time.
439  SourceManager &SM = M->getContext().getSourceManager();
440  if (CurLoc == PrevLoc
441       || (SM.getLineNumber(CurLoc) == SM.getLineNumber(PrevLoc)
442           && SM.isFromSameFile(CurLoc, PrevLoc)))
443    return;
444
445  // Update last state.
446  PrevLoc = CurLoc;
447
448  // Get the appropriate compile unit.
449  llvm::DICompileUnit Unit = getOrCreateCompileUnit(CurLoc);
450  DebugFactory.InsertStopPoint(Unit, SM.getLogicalLineNumber(CurLoc),
451                               SM.getLogicalColumnNumber(CurLoc),
452                               Builder.GetInsertBlock());
453}
454
455/// EmitRegionStart- Constructs the debug code for entering a declarative
456/// region - "llvm.dbg.region.start.".
457void CGDebugInfo::EmitRegionStart(llvm::Function *Fn, CGBuilderTy &Builder) {
458  llvm::DIDescriptor D;
459  if (!RegionStack.empty())
460    D = RegionStack.back();
461  D = DebugFactory.CreateBlock(D);
462  RegionStack.push_back(D);
463  DebugFactory.InsertRegionStart(D, Builder.GetInsertBlock());
464}
465
466/// EmitRegionEnd - Constructs the debug code for exiting a declarative
467/// region - "llvm.dbg.region.end."
468void CGDebugInfo::EmitRegionEnd(llvm::Function *Fn, CGBuilderTy &Builder) {
469  assert(!RegionStack.empty() && "Region stack mismatch, stack empty!");
470
471  // Provide an region stop point.
472  EmitStopPoint(Fn, Builder);
473
474  DebugFactory.InsertRegionEnd(RegionStack.back(), Builder.GetInsertBlock());
475  RegionStack.pop_back();
476}
477
478/// EmitDeclare - Emit local variable declaration debug info.
479void CGDebugInfo::EmitDeclare(const VarDecl *Decl, unsigned Tag,
480                              llvm::Value *Storage, CGBuilderTy &Builder) {
481  assert(!RegionStack.empty() && "Region stack mismatch, stack empty!");
482
483  // Get location information.
484  SourceManager &SM = M->getContext().getSourceManager();
485  uint64_t Line = SM.getLogicalLineNumber(Decl->getLocation());
486  llvm::DICompileUnit Unit = getOrCreateCompileUnit(Decl->getLocation());
487
488  // Create the descriptor for the variable.
489  llvm::DIVariable D =
490    DebugFactory.CreateVariable(Tag, RegionStack.back(), Decl->getName(),
491                                Unit, Line,
492                                getOrCreateType(Decl->getType(), Unit));
493  // Insert an llvm.dbg.declare into the current block.
494  DebugFactory.InsertDeclare(Storage, D, Builder.GetInsertBlock());
495}
496
497void CGDebugInfo::EmitDeclareOfAutoVariable(const VarDecl *Decl,
498                                            llvm::Value *Storage,
499                                            CGBuilderTy &Builder) {
500  EmitDeclare(Decl, llvm::dwarf::DW_TAG_auto_variable, Storage, Builder);
501}
502
503/// EmitDeclareOfArgVariable - Emit call to llvm.dbg.declare for an argument
504/// variable declaration.
505void CGDebugInfo::EmitDeclareOfArgVariable(const VarDecl *Decl, llvm::Value *AI,
506                                           CGBuilderTy &Builder) {
507  EmitDeclare(Decl, llvm::dwarf::DW_TAG_arg_variable, AI, Builder);
508}
509
510
511
512/// EmitGlobalVariable - Emit information about a global variable.
513void CGDebugInfo::EmitGlobalVariable(llvm::GlobalVariable *Var,
514                                     const VarDecl *Decl) {
515  // Create global variable debug descriptor.
516  llvm::DICompileUnit Unit = getOrCreateCompileUnit(Decl->getLocation());
517  SourceManager &SM = M->getContext().getSourceManager();
518  uint64_t LineNo = SM.getLogicalLineNumber(Decl->getLocation());
519  const char *Name = Decl->getIdentifierName();
520
521  DebugFactory.CreateGlobalVariable(Unit, Name, Name, "", Unit, LineNo,
522                                    getOrCreateType(Decl->getType(), Unit),
523                                    Var->hasInternalLinkage(),
524                                    true/*definition*/, Var);
525}
526
527