1#include "DwarfCompileUnit.h"
2#include "DwarfExpression.h"
3#include "llvm/CodeGen/MachineFunction.h"
4#include "llvm/IR/Constants.h"
5#include "llvm/IR/DataLayout.h"
6#include "llvm/IR/GlobalValue.h"
7#include "llvm/IR/GlobalVariable.h"
8#include "llvm/IR/Instruction.h"
9#include "llvm/MC/MCAsmInfo.h"
10#include "llvm/MC/MCStreamer.h"
11#include "llvm/Target/TargetFrameLowering.h"
12#include "llvm/Target/TargetLoweringObjectFile.h"
13#include "llvm/Target/TargetMachine.h"
14#include "llvm/Target/TargetRegisterInfo.h"
15#include "llvm/Target/TargetSubtargetInfo.h"
16
17namespace llvm {
18
19DwarfCompileUnit::DwarfCompileUnit(unsigned UID, const DICompileUnit *Node,
20                                   AsmPrinter *A, DwarfDebug *DW,
21                                   DwarfFile *DWU)
22    : DwarfUnit(UID, dwarf::DW_TAG_compile_unit, Node, A, DW, DWU),
23      Skeleton(nullptr), BaseAddress(nullptr) {
24  insertDIE(Node, &getUnitDie());
25}
26
27/// addLabelAddress - Add a dwarf label attribute data and value using
28/// DW_FORM_addr or DW_FORM_GNU_addr_index.
29///
30void DwarfCompileUnit::addLabelAddress(DIE &Die, dwarf::Attribute Attribute,
31                                       const MCSymbol *Label) {
32
33  // Don't use the address pool in non-fission or in the skeleton unit itself.
34  // FIXME: Once GDB supports this, it's probably worthwhile using the address
35  // pool from the skeleton - maybe even in non-fission (possibly fewer
36  // relocations by sharing them in the pool, but we have other ideas about how
37  // to reduce the number of relocations as well/instead).
38  if (!DD->useSplitDwarf() || !Skeleton)
39    return addLocalLabelAddress(Die, Attribute, Label);
40
41  if (Label)
42    DD->addArangeLabel(SymbolCU(this, Label));
43
44  unsigned idx = DD->getAddressPool().getIndex(Label);
45  Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_GNU_addr_index,
46               DIEInteger(idx));
47}
48
49void DwarfCompileUnit::addLocalLabelAddress(DIE &Die,
50                                            dwarf::Attribute Attribute,
51                                            const MCSymbol *Label) {
52  if (Label)
53    DD->addArangeLabel(SymbolCU(this, Label));
54
55  if (Label)
56    Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_addr,
57                 DIELabel(Label));
58  else
59    Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_addr,
60                 DIEInteger(0));
61}
62
63unsigned DwarfCompileUnit::getOrCreateSourceID(StringRef FileName,
64                                               StringRef DirName) {
65  // If we print assembly, we can't separate .file entries according to
66  // compile units. Thus all files will belong to the default compile unit.
67
68  // FIXME: add a better feature test than hasRawTextSupport. Even better,
69  // extend .file to support this.
70  return Asm->OutStreamer->EmitDwarfFileDirective(
71      0, DirName, FileName,
72      Asm->OutStreamer->hasRawTextSupport() ? 0 : getUniqueID());
73}
74
75// Return const expression if value is a GEP to access merged global
76// constant. e.g.
77// i8* getelementptr ({ i8, i8, i8, i8 }* @_MergedGlobals, i32 0, i32 0)
78static const ConstantExpr *getMergedGlobalExpr(const Value *V) {
79  const ConstantExpr *CE = dyn_cast_or_null<ConstantExpr>(V);
80  if (!CE || CE->getNumOperands() != 3 ||
81      CE->getOpcode() != Instruction::GetElementPtr)
82    return nullptr;
83
84  // First operand points to a global struct.
85  Value *Ptr = CE->getOperand(0);
86  if (!isa<GlobalValue>(Ptr) ||
87      !isa<StructType>(cast<PointerType>(Ptr->getType())->getElementType()))
88    return nullptr;
89
90  // Second operand is zero.
91  const ConstantInt *CI = dyn_cast_or_null<ConstantInt>(CE->getOperand(1));
92  if (!CI || !CI->isZero())
93    return nullptr;
94
95  // Third operand is offset.
96  if (!isa<ConstantInt>(CE->getOperand(2)))
97    return nullptr;
98
99  return CE;
100}
101
102/// getOrCreateGlobalVariableDIE - get or create global variable DIE.
103DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(
104    const DIGlobalVariable *GV) {
105  // Check for pre-existence.
106  if (DIE *Die = getDIE(GV))
107    return Die;
108
109  assert(GV);
110
111  auto *GVContext = GV->getScope();
112  auto *GTy = DD->resolve(GV->getType());
113
114  // Construct the context before querying for the existence of the DIE in
115  // case such construction creates the DIE.
116  DIE *ContextDIE = getOrCreateContextDIE(GVContext);
117
118  // Add to map.
119  DIE *VariableDIE = &createAndAddDIE(GV->getTag(), *ContextDIE, GV);
120  DIScope *DeclContext;
121  if (auto *SDMDecl = GV->getStaticDataMemberDeclaration()) {
122    DeclContext = resolve(SDMDecl->getScope());
123    assert(SDMDecl->isStaticMember() && "Expected static member decl");
124    assert(GV->isDefinition());
125    // We need the declaration DIE that is in the static member's class.
126    DIE *VariableSpecDIE = getOrCreateStaticMemberDIE(SDMDecl);
127    addDIEEntry(*VariableDIE, dwarf::DW_AT_specification, *VariableSpecDIE);
128  } else {
129    DeclContext = GV->getScope();
130    // Add name and type.
131    addString(*VariableDIE, dwarf::DW_AT_name, GV->getDisplayName());
132    addType(*VariableDIE, GTy);
133
134    // Add scoping info.
135    if (!GV->isLocalToUnit())
136      addFlag(*VariableDIE, dwarf::DW_AT_external);
137
138    // Add line number info.
139    addSourceLine(*VariableDIE, GV);
140  }
141
142  if (!GV->isDefinition())
143    addFlag(*VariableDIE, dwarf::DW_AT_declaration);
144  else
145    addGlobalName(GV->getName(), *VariableDIE, DeclContext);
146
147  // Add location.
148  bool addToAccelTable = false;
149  if (auto *Global = dyn_cast_or_null<GlobalVariable>(GV->getVariable())) {
150    addToAccelTable = true;
151    DIELoc *Loc = new (DIEValueAllocator) DIELoc;
152    const MCSymbol *Sym = Asm->getSymbol(Global);
153    if (Global->isThreadLocal()) {
154      if (Asm->TM.Options.EmulatedTLS) {
155        // TODO: add debug info for emulated thread local mode.
156      } else {
157        // FIXME: Make this work with -gsplit-dwarf.
158        unsigned PointerSize = Asm->getDataLayout().getPointerSize();
159        assert((PointerSize == 4 || PointerSize == 8) &&
160               "Add support for other sizes if necessary");
161        // Based on GCC's support for TLS:
162        if (!DD->useSplitDwarf()) {
163          // 1) Start with a constNu of the appropriate pointer size
164          addUInt(*Loc, dwarf::DW_FORM_data1, PointerSize == 4
165                                                  ? dwarf::DW_OP_const4u
166                                                  : dwarf::DW_OP_const8u);
167          // 2) containing the (relocated) offset of the TLS variable
168          //    within the module's TLS block.
169          addExpr(*Loc, dwarf::DW_FORM_udata,
170                  Asm->getObjFileLowering().getDebugThreadLocalSymbol(Sym));
171        } else {
172          addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_const_index);
173          addUInt(*Loc, dwarf::DW_FORM_udata,
174                  DD->getAddressPool().getIndex(Sym, /* TLS */ true));
175        }
176        // 3) followed by an OP to make the debugger do a TLS lookup.
177        addUInt(*Loc, dwarf::DW_FORM_data1,
178                DD->useGNUTLSOpcode() ? dwarf::DW_OP_GNU_push_tls_address
179                                      : dwarf::DW_OP_form_tls_address);
180      }
181    } else {
182      DD->addArangeLabel(SymbolCU(this, Sym));
183      addOpAddress(*Loc, Sym);
184    }
185
186    addBlock(*VariableDIE, dwarf::DW_AT_location, Loc);
187    addLinkageName(*VariableDIE, GV->getLinkageName());
188  } else if (const ConstantInt *CI =
189                 dyn_cast_or_null<ConstantInt>(GV->getVariable())) {
190    addConstantValue(*VariableDIE, CI, GTy);
191  } else if (const ConstantExpr *CE = getMergedGlobalExpr(GV->getVariable())) {
192    addToAccelTable = true;
193    // GV is a merged global.
194    DIELoc *Loc = new (DIEValueAllocator) DIELoc;
195    Value *Ptr = CE->getOperand(0);
196    MCSymbol *Sym = Asm->getSymbol(cast<GlobalValue>(Ptr));
197    DD->addArangeLabel(SymbolCU(this, Sym));
198    addOpAddress(*Loc, Sym);
199    addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_constu);
200    SmallVector<Value *, 3> Idx(CE->op_begin() + 1, CE->op_end());
201    addUInt(*Loc, dwarf::DW_FORM_udata,
202            Asm->getDataLayout().getIndexedOffset(Ptr->getType(), Idx));
203    addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
204    addBlock(*VariableDIE, dwarf::DW_AT_location, Loc);
205  }
206
207  if (addToAccelTable) {
208    DD->addAccelName(GV->getName(), *VariableDIE);
209
210    // If the linkage name is different than the name, go ahead and output
211    // that as well into the name table.
212    if (GV->getLinkageName() != "" && GV->getName() != GV->getLinkageName())
213      DD->addAccelName(GV->getLinkageName(), *VariableDIE);
214  }
215
216  return VariableDIE;
217}
218
219void DwarfCompileUnit::addRange(RangeSpan Range) {
220  bool SameAsPrevCU = this == DD->getPrevCU();
221  DD->setPrevCU(this);
222  // If we have no current ranges just add the range and return, otherwise,
223  // check the current section and CU against the previous section and CU we
224  // emitted into and the subprogram was contained within. If these are the
225  // same then extend our current range, otherwise add this as a new range.
226  if (CURanges.empty() || !SameAsPrevCU ||
227      (&CURanges.back().getEnd()->getSection() !=
228       &Range.getEnd()->getSection())) {
229    CURanges.push_back(Range);
230    return;
231  }
232
233  CURanges.back().setEnd(Range.getEnd());
234}
235
236DIE::value_iterator
237DwarfCompileUnit::addSectionLabel(DIE &Die, dwarf::Attribute Attribute,
238                                  const MCSymbol *Label, const MCSymbol *Sec) {
239  if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
240    return addLabel(Die, Attribute,
241                    DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
242                                               : dwarf::DW_FORM_data4,
243                    Label);
244  return addSectionDelta(Die, Attribute, Label, Sec);
245}
246
247void DwarfCompileUnit::initStmtList() {
248  // Define start line table label for each Compile Unit.
249  MCSymbol *LineTableStartSym =
250      Asm->OutStreamer->getDwarfLineTableSymbol(getUniqueID());
251
252  // DW_AT_stmt_list is a offset of line number information for this
253  // compile unit in debug_line section. For split dwarf this is
254  // left in the skeleton CU and so not included.
255  // The line table entries are not always emitted in assembly, so it
256  // is not okay to use line_table_start here.
257  const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
258  StmtListValue =
259      addSectionLabel(UnitDie, dwarf::DW_AT_stmt_list, LineTableStartSym,
260                      TLOF.getDwarfLineSection()->getBeginSymbol());
261}
262
263void DwarfCompileUnit::applyStmtList(DIE &D) {
264  D.addValue(DIEValueAllocator, *StmtListValue);
265}
266
267void DwarfCompileUnit::attachLowHighPC(DIE &D, const MCSymbol *Begin,
268                                       const MCSymbol *End) {
269  assert(Begin && "Begin label should not be null!");
270  assert(End && "End label should not be null!");
271  assert(Begin->isDefined() && "Invalid starting label");
272  assert(End->isDefined() && "Invalid end label");
273
274  addLabelAddress(D, dwarf::DW_AT_low_pc, Begin);
275  if (DD->getDwarfVersion() < 4)
276    addLabelAddress(D, dwarf::DW_AT_high_pc, End);
277  else
278    addLabelDelta(D, dwarf::DW_AT_high_pc, End, Begin);
279}
280
281// Find DIE for the given subprogram and attach appropriate DW_AT_low_pc
282// and DW_AT_high_pc attributes. If there are global variables in this
283// scope then create and insert DIEs for these variables.
284DIE &DwarfCompileUnit::updateSubprogramScopeDIE(const DISubprogram *SP) {
285  DIE *SPDie = getOrCreateSubprogramDIE(SP, includeMinimalInlineScopes());
286
287  attachLowHighPC(*SPDie, Asm->getFunctionBegin(), Asm->getFunctionEnd());
288  if (!DD->getCurrentFunction()->getTarget().Options.DisableFramePointerElim(
289          *DD->getCurrentFunction()))
290    addFlag(*SPDie, dwarf::DW_AT_APPLE_omit_frame_ptr);
291
292  // Only include DW_AT_frame_base in full debug info
293  if (!includeMinimalInlineScopes()) {
294    const TargetRegisterInfo *RI = Asm->MF->getSubtarget().getRegisterInfo();
295    MachineLocation Location(RI->getFrameRegister(*Asm->MF));
296    if (RI->isPhysicalRegister(Location.getReg()))
297      addAddress(*SPDie, dwarf::DW_AT_frame_base, Location);
298  }
299
300  // Add name to the name table, we do this here because we're guaranteed
301  // to have concrete versions of our DW_TAG_subprogram nodes.
302  DD->addSubprogramNames(SP, *SPDie);
303
304  return *SPDie;
305}
306
307// Construct a DIE for this scope.
308void DwarfCompileUnit::constructScopeDIE(
309    LexicalScope *Scope, SmallVectorImpl<DIE *> &FinalChildren) {
310  if (!Scope || !Scope->getScopeNode())
311    return;
312
313  auto *DS = Scope->getScopeNode();
314
315  assert((Scope->getInlinedAt() || !isa<DISubprogram>(DS)) &&
316         "Only handle inlined subprograms here, use "
317         "constructSubprogramScopeDIE for non-inlined "
318         "subprograms");
319
320  SmallVector<DIE *, 8> Children;
321
322  // We try to create the scope DIE first, then the children DIEs. This will
323  // avoid creating un-used children then removing them later when we find out
324  // the scope DIE is null.
325  DIE *ScopeDIE;
326  if (Scope->getParent() && isa<DISubprogram>(DS)) {
327    ScopeDIE = constructInlinedScopeDIE(Scope);
328    if (!ScopeDIE)
329      return;
330    // We create children when the scope DIE is not null.
331    createScopeChildrenDIE(Scope, Children);
332  } else {
333    // Early exit when we know the scope DIE is going to be null.
334    if (DD->isLexicalScopeDIENull(Scope))
335      return;
336
337    unsigned ChildScopeCount;
338
339    // We create children here when we know the scope DIE is not going to be
340    // null and the children will be added to the scope DIE.
341    createScopeChildrenDIE(Scope, Children, &ChildScopeCount);
342
343    // Skip imported directives in gmlt-like data.
344    if (!includeMinimalInlineScopes()) {
345      // There is no need to emit empty lexical block DIE.
346      for (const auto *IE : ImportedEntities[DS])
347        Children.push_back(
348            constructImportedEntityDIE(cast<DIImportedEntity>(IE)));
349    }
350
351    // If there are only other scopes as children, put them directly in the
352    // parent instead, as this scope would serve no purpose.
353    if (Children.size() == ChildScopeCount) {
354      FinalChildren.insert(FinalChildren.end(),
355                           std::make_move_iterator(Children.begin()),
356                           std::make_move_iterator(Children.end()));
357      return;
358    }
359    ScopeDIE = constructLexicalScopeDIE(Scope);
360    assert(ScopeDIE && "Scope DIE should not be null.");
361  }
362
363  // Add children
364  for (auto &I : Children)
365    ScopeDIE->addChild(std::move(I));
366
367  FinalChildren.push_back(std::move(ScopeDIE));
368}
369
370DIE::value_iterator
371DwarfCompileUnit::addSectionDelta(DIE &Die, dwarf::Attribute Attribute,
372                                  const MCSymbol *Hi, const MCSymbol *Lo) {
373  return Die.addValue(DIEValueAllocator, Attribute,
374                      DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
375                                                 : dwarf::DW_FORM_data4,
376                      new (DIEValueAllocator) DIEDelta(Hi, Lo));
377}
378
379void DwarfCompileUnit::addScopeRangeList(DIE &ScopeDIE,
380                                         SmallVector<RangeSpan, 2> Range) {
381  const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
382
383  // Emit offset in .debug_range as a relocatable label. emitDIE will handle
384  // emitting it appropriately.
385  const MCSymbol *RangeSectionSym =
386      TLOF.getDwarfRangesSection()->getBeginSymbol();
387
388  RangeSpanList List(Asm->createTempSymbol("debug_ranges"), std::move(Range));
389
390  // Under fission, ranges are specified by constant offsets relative to the
391  // CU's DW_AT_GNU_ranges_base.
392  if (isDwoUnit())
393    addSectionDelta(ScopeDIE, dwarf::DW_AT_ranges, List.getSym(),
394                    RangeSectionSym);
395  else
396    addSectionLabel(ScopeDIE, dwarf::DW_AT_ranges, List.getSym(),
397                    RangeSectionSym);
398
399  // Add the range list to the set of ranges to be emitted.
400  (Skeleton ? Skeleton : this)->CURangeLists.push_back(std::move(List));
401}
402
403void DwarfCompileUnit::attachRangesOrLowHighPC(
404    DIE &Die, SmallVector<RangeSpan, 2> Ranges) {
405  if (Ranges.size() == 1) {
406    const auto &single = Ranges.front();
407    attachLowHighPC(Die, single.getStart(), single.getEnd());
408  } else
409    addScopeRangeList(Die, std::move(Ranges));
410}
411
412void DwarfCompileUnit::attachRangesOrLowHighPC(
413    DIE &Die, const SmallVectorImpl<InsnRange> &Ranges) {
414  SmallVector<RangeSpan, 2> List;
415  List.reserve(Ranges.size());
416  for (const InsnRange &R : Ranges)
417    List.push_back(RangeSpan(DD->getLabelBeforeInsn(R.first),
418                             DD->getLabelAfterInsn(R.second)));
419  attachRangesOrLowHighPC(Die, std::move(List));
420}
421
422// This scope represents inlined body of a function. Construct DIE to
423// represent this concrete inlined copy of the function.
424DIE *DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope) {
425  assert(Scope->getScopeNode());
426  auto *DS = Scope->getScopeNode();
427  auto *InlinedSP = getDISubprogram(DS);
428  // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
429  // was inlined from another compile unit.
430  DIE *OriginDIE = DU->getAbstractSPDies()[InlinedSP];
431  assert(OriginDIE && "Unable to find original DIE for an inlined subprogram.");
432
433  auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_inlined_subroutine);
434  addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *OriginDIE);
435
436  attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
437
438  // Add the call site information to the DIE.
439  const DILocation *IA = Scope->getInlinedAt();
440  addUInt(*ScopeDIE, dwarf::DW_AT_call_file, None,
441          getOrCreateSourceID(IA->getFilename(), IA->getDirectory()));
442  addUInt(*ScopeDIE, dwarf::DW_AT_call_line, None, IA->getLine());
443  if (IA->getDiscriminator())
444    addUInt(*ScopeDIE, dwarf::DW_AT_GNU_discriminator, None,
445            IA->getDiscriminator());
446
447  // Add name to the name table, we do this here because we're guaranteed
448  // to have concrete versions of our DW_TAG_inlined_subprogram nodes.
449  DD->addSubprogramNames(InlinedSP, *ScopeDIE);
450
451  return ScopeDIE;
452}
453
454// Construct new DW_TAG_lexical_block for this scope and attach
455// DW_AT_low_pc/DW_AT_high_pc labels.
456DIE *DwarfCompileUnit::constructLexicalScopeDIE(LexicalScope *Scope) {
457  if (DD->isLexicalScopeDIENull(Scope))
458    return nullptr;
459
460  auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_lexical_block);
461  if (Scope->isAbstractScope())
462    return ScopeDIE;
463
464  attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
465
466  return ScopeDIE;
467}
468
469/// constructVariableDIE - Construct a DIE for the given DbgVariable.
470DIE *DwarfCompileUnit::constructVariableDIE(DbgVariable &DV, bool Abstract) {
471  auto D = constructVariableDIEImpl(DV, Abstract);
472  DV.setDIE(*D);
473  return D;
474}
475
476DIE *DwarfCompileUnit::constructVariableDIEImpl(const DbgVariable &DV,
477                                                bool Abstract) {
478  // Define variable debug information entry.
479  auto VariableDie = DIE::get(DIEValueAllocator, DV.getTag());
480
481  if (Abstract) {
482    applyVariableAttributes(DV, *VariableDie);
483    return VariableDie;
484  }
485
486  // Add variable address.
487
488  unsigned Offset = DV.getDebugLocListIndex();
489  if (Offset != ~0U) {
490    addLocationList(*VariableDie, dwarf::DW_AT_location, Offset);
491    return VariableDie;
492  }
493
494  // Check if variable is described by a DBG_VALUE instruction.
495  if (const MachineInstr *DVInsn = DV.getMInsn()) {
496    assert(DVInsn->getNumOperands() == 4);
497    if (DVInsn->getOperand(0).isReg()) {
498      const MachineOperand RegOp = DVInsn->getOperand(0);
499      // If the second operand is an immediate, this is an indirect value.
500      if (DVInsn->getOperand(1).isImm()) {
501        MachineLocation Location(RegOp.getReg(),
502                                 DVInsn->getOperand(1).getImm());
503        addVariableAddress(DV, *VariableDie, Location);
504      } else if (RegOp.getReg())
505        addVariableAddress(DV, *VariableDie, MachineLocation(RegOp.getReg()));
506    } else if (DVInsn->getOperand(0).isImm())
507      addConstantValue(*VariableDie, DVInsn->getOperand(0), DV.getType());
508    else if (DVInsn->getOperand(0).isFPImm())
509      addConstantFPValue(*VariableDie, DVInsn->getOperand(0));
510    else if (DVInsn->getOperand(0).isCImm())
511      addConstantValue(*VariableDie, DVInsn->getOperand(0).getCImm(),
512                       DV.getType());
513
514    return VariableDie;
515  }
516
517  // .. else use frame index.
518  if (DV.getFrameIndex().empty())
519    return VariableDie;
520
521  auto Expr = DV.getExpression().begin();
522  DIELoc *Loc = new (DIEValueAllocator) DIELoc;
523  DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
524  for (auto FI : DV.getFrameIndex()) {
525    unsigned FrameReg = 0;
526    const TargetFrameLowering *TFI = Asm->MF->getSubtarget().getFrameLowering();
527    int Offset = TFI->getFrameIndexReference(*Asm->MF, FI, FrameReg);
528    assert(Expr != DV.getExpression().end() && "Wrong number of expressions");
529    DwarfExpr.AddMachineRegIndirect(FrameReg, Offset);
530    DwarfExpr.AddExpression((*Expr)->expr_op_begin(), (*Expr)->expr_op_end());
531    ++Expr;
532  }
533  addBlock(*VariableDie, dwarf::DW_AT_location, Loc);
534
535  return VariableDie;
536}
537
538DIE *DwarfCompileUnit::constructVariableDIE(DbgVariable &DV,
539                                            const LexicalScope &Scope,
540                                            DIE *&ObjectPointer) {
541  auto Var = constructVariableDIE(DV, Scope.isAbstractScope());
542  if (DV.isObjectPointer())
543    ObjectPointer = Var;
544  return Var;
545}
546
547DIE *DwarfCompileUnit::createScopeChildrenDIE(LexicalScope *Scope,
548                                              SmallVectorImpl<DIE *> &Children,
549                                              unsigned *ChildScopeCount) {
550  DIE *ObjectPointer = nullptr;
551
552  for (DbgVariable *DV : DU->getScopeVariables().lookup(Scope))
553    Children.push_back(constructVariableDIE(*DV, *Scope, ObjectPointer));
554
555  unsigned ChildCountWithoutScopes = Children.size();
556
557  for (LexicalScope *LS : Scope->getChildren())
558    constructScopeDIE(LS, Children);
559
560  if (ChildScopeCount)
561    *ChildScopeCount = Children.size() - ChildCountWithoutScopes;
562
563  return ObjectPointer;
564}
565
566void DwarfCompileUnit::constructSubprogramScopeDIE(LexicalScope *Scope) {
567  assert(Scope && Scope->getScopeNode());
568  assert(!Scope->getInlinedAt());
569  assert(!Scope->isAbstractScope());
570  auto *Sub = cast<DISubprogram>(Scope->getScopeNode());
571
572  DD->getProcessedSPNodes().insert(Sub);
573
574  DIE &ScopeDIE = updateSubprogramScopeDIE(Sub);
575
576  // If this is a variadic function, add an unspecified parameter.
577  DITypeRefArray FnArgs = Sub->getType()->getTypeArray();
578
579  // Collect lexical scope children first.
580  // ObjectPointer might be a local (non-argument) local variable if it's a
581  // block's synthetic this pointer.
582  if (DIE *ObjectPointer = createAndAddScopeChildren(Scope, ScopeDIE))
583    addDIEEntry(ScopeDIE, dwarf::DW_AT_object_pointer, *ObjectPointer);
584
585  // If we have a single element of null, it is a function that returns void.
586  // If we have more than one elements and the last one is null, it is a
587  // variadic function.
588  if (FnArgs.size() > 1 && !FnArgs[FnArgs.size() - 1] &&
589      !includeMinimalInlineScopes())
590    ScopeDIE.addChild(
591        DIE::get(DIEValueAllocator, dwarf::DW_TAG_unspecified_parameters));
592}
593
594DIE *DwarfCompileUnit::createAndAddScopeChildren(LexicalScope *Scope,
595                                                 DIE &ScopeDIE) {
596  // We create children when the scope DIE is not null.
597  SmallVector<DIE *, 8> Children;
598  DIE *ObjectPointer = createScopeChildrenDIE(Scope, Children);
599
600  // Add children
601  for (auto &I : Children)
602    ScopeDIE.addChild(std::move(I));
603
604  return ObjectPointer;
605}
606
607void DwarfCompileUnit::constructAbstractSubprogramScopeDIE(
608    LexicalScope *Scope) {
609  DIE *&AbsDef = DU->getAbstractSPDies()[Scope->getScopeNode()];
610  if (AbsDef)
611    return;
612
613  auto *SP = cast<DISubprogram>(Scope->getScopeNode());
614
615  DIE *ContextDIE;
616
617  if (includeMinimalInlineScopes())
618    ContextDIE = &getUnitDie();
619  // Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
620  // the important distinction that the debug node is not associated with the
621  // DIE (since the debug node will be associated with the concrete DIE, if
622  // any). It could be refactored to some common utility function.
623  else if (auto *SPDecl = SP->getDeclaration()) {
624    ContextDIE = &getUnitDie();
625    getOrCreateSubprogramDIE(SPDecl);
626  } else
627    ContextDIE = getOrCreateContextDIE(resolve(SP->getScope()));
628
629  // Passing null as the associated node because the abstract definition
630  // shouldn't be found by lookup.
631  AbsDef = &createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE, nullptr);
632  applySubprogramAttributesToDefinition(SP, *AbsDef);
633
634  if (!includeMinimalInlineScopes())
635    addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
636  if (DIE *ObjectPointer = createAndAddScopeChildren(Scope, *AbsDef))
637    addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
638}
639
640DIE *DwarfCompileUnit::constructImportedEntityDIE(
641    const DIImportedEntity *Module) {
642  DIE *IMDie = DIE::get(DIEValueAllocator, (dwarf::Tag)Module->getTag());
643  insertDIE(Module, IMDie);
644  DIE *EntityDie;
645  auto *Entity = resolve(Module->getEntity());
646  if (auto *NS = dyn_cast<DINamespace>(Entity))
647    EntityDie = getOrCreateNameSpace(NS);
648  else if (auto *M = dyn_cast<DIModule>(Entity))
649    EntityDie = getOrCreateModule(M);
650  else if (auto *SP = dyn_cast<DISubprogram>(Entity))
651    EntityDie = getOrCreateSubprogramDIE(SP);
652  else if (auto *T = dyn_cast<DIType>(Entity))
653    EntityDie = getOrCreateTypeDIE(T);
654  else if (auto *GV = dyn_cast<DIGlobalVariable>(Entity))
655    EntityDie = getOrCreateGlobalVariableDIE(GV);
656  else
657    EntityDie = getDIE(Entity);
658  assert(EntityDie);
659  addSourceLine(*IMDie, Module->getLine(), Module->getScope()->getFilename(),
660                Module->getScope()->getDirectory());
661  addDIEEntry(*IMDie, dwarf::DW_AT_import, *EntityDie);
662  StringRef Name = Module->getName();
663  if (!Name.empty())
664    addString(*IMDie, dwarf::DW_AT_name, Name);
665
666  return IMDie;
667}
668
669void DwarfCompileUnit::finishSubprogramDefinition(const DISubprogram *SP) {
670  DIE *D = getDIE(SP);
671  if (DIE *AbsSPDIE = DU->getAbstractSPDies().lookup(SP)) {
672    if (D)
673      // If this subprogram has an abstract definition, reference that
674      addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
675  } else {
676    if (!D && !includeMinimalInlineScopes())
677      // Lazily construct the subprogram if we didn't see either concrete or
678      // inlined versions during codegen. (except in -gmlt ^ where we want
679      // to omit these entirely)
680      D = getOrCreateSubprogramDIE(SP);
681    if (D)
682      // And attach the attributes
683      applySubprogramAttributesToDefinition(SP, *D);
684  }
685}
686void DwarfCompileUnit::collectDeadVariables(const DISubprogram *SP) {
687  assert(SP && "CU's subprogram list contains a non-subprogram");
688  assert(SP->isDefinition() &&
689         "CU's subprogram list contains a subprogram declaration");
690  auto Variables = SP->getVariables();
691  if (Variables.size() == 0)
692    return;
693
694  DIE *SPDIE = DU->getAbstractSPDies().lookup(SP);
695  if (!SPDIE)
696    SPDIE = getDIE(SP);
697  assert(SPDIE);
698  for (const DILocalVariable *DV : Variables) {
699    DbgVariable NewVar(DV, /* IA */ nullptr, DD);
700    auto VariableDie = constructVariableDIE(NewVar);
701    applyVariableAttributes(NewVar, *VariableDie);
702    SPDIE->addChild(std::move(VariableDie));
703  }
704}
705
706void DwarfCompileUnit::emitHeader(bool UseOffsets) {
707  // Don't bother labeling the .dwo unit, as its offset isn't used.
708  if (!Skeleton) {
709    LabelBegin = Asm->createTempSymbol("cu_begin");
710    Asm->OutStreamer->EmitLabel(LabelBegin);
711  }
712
713  DwarfUnit::emitHeader(UseOffsets);
714}
715
716/// addGlobalName - Add a new global name to the compile unit.
717void DwarfCompileUnit::addGlobalName(StringRef Name, DIE &Die,
718                                     const DIScope *Context) {
719  if (includeMinimalInlineScopes())
720    return;
721  std::string FullName = getParentContextString(Context) + Name.str();
722  GlobalNames[FullName] = &Die;
723}
724
725/// Add a new global type to the unit.
726void DwarfCompileUnit::addGlobalType(const DIType *Ty, const DIE &Die,
727                                     const DIScope *Context) {
728  if (includeMinimalInlineScopes())
729    return;
730  std::string FullName = getParentContextString(Context) + Ty->getName().str();
731  GlobalTypes[FullName] = &Die;
732}
733
734/// addVariableAddress - Add DW_AT_location attribute for a
735/// DbgVariable based on provided MachineLocation.
736void DwarfCompileUnit::addVariableAddress(const DbgVariable &DV, DIE &Die,
737                                          MachineLocation Location) {
738  if (DV.hasComplexAddress())
739    addComplexAddress(DV, Die, dwarf::DW_AT_location, Location);
740  else if (DV.isBlockByrefVariable())
741    addBlockByrefAddress(DV, Die, dwarf::DW_AT_location, Location);
742  else
743    addAddress(Die, dwarf::DW_AT_location, Location);
744}
745
746/// Add an address attribute to a die based on the location provided.
747void DwarfCompileUnit::addAddress(DIE &Die, dwarf::Attribute Attribute,
748                                  const MachineLocation &Location) {
749  DIELoc *Loc = new (DIEValueAllocator) DIELoc;
750
751  bool validReg;
752  if (Location.isReg())
753    validReg = addRegisterOpPiece(*Loc, Location.getReg());
754  else
755    validReg = addRegisterOffset(*Loc, Location.getReg(), Location.getOffset());
756
757  if (!validReg)
758    return;
759
760  // Now attach the location information to the DIE.
761  addBlock(Die, Attribute, Loc);
762}
763
764/// Start with the address based on the location provided, and generate the
765/// DWARF information necessary to find the actual variable given the extra
766/// address information encoded in the DbgVariable, starting from the starting
767/// location.  Add the DWARF information to the die.
768void DwarfCompileUnit::addComplexAddress(const DbgVariable &DV, DIE &Die,
769                                         dwarf::Attribute Attribute,
770                                         const MachineLocation &Location) {
771  DIELoc *Loc = new (DIEValueAllocator) DIELoc;
772  DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
773  assert(DV.getExpression().size() == 1);
774  const DIExpression *Expr = DV.getExpression().back();
775  bool ValidReg;
776  if (Location.getOffset()) {
777    ValidReg = DwarfExpr.AddMachineRegIndirect(Location.getReg(),
778                                               Location.getOffset());
779    if (ValidReg)
780      DwarfExpr.AddExpression(Expr->expr_op_begin(), Expr->expr_op_end());
781  } else
782    ValidReg = DwarfExpr.AddMachineRegExpression(Expr, Location.getReg());
783
784  // Now attach the location information to the DIE.
785  if (ValidReg)
786    addBlock(Die, Attribute, Loc);
787}
788
789/// Add a Dwarf loclistptr attribute data and value.
790void DwarfCompileUnit::addLocationList(DIE &Die, dwarf::Attribute Attribute,
791                                       unsigned Index) {
792  dwarf::Form Form = DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
793                                                : dwarf::DW_FORM_data4;
794  Die.addValue(DIEValueAllocator, Attribute, Form, DIELocList(Index));
795}
796
797void DwarfCompileUnit::applyVariableAttributes(const DbgVariable &Var,
798                                               DIE &VariableDie) {
799  StringRef Name = Var.getName();
800  if (!Name.empty())
801    addString(VariableDie, dwarf::DW_AT_name, Name);
802  addSourceLine(VariableDie, Var.getVariable());
803  addType(VariableDie, Var.getType());
804  if (Var.isArtificial())
805    addFlag(VariableDie, dwarf::DW_AT_artificial);
806}
807
808/// Add a Dwarf expression attribute data and value.
809void DwarfCompileUnit::addExpr(DIELoc &Die, dwarf::Form Form,
810                               const MCExpr *Expr) {
811  Die.addValue(DIEValueAllocator, (dwarf::Attribute)0, Form, DIEExpr(Expr));
812}
813
814void DwarfCompileUnit::applySubprogramAttributesToDefinition(
815    const DISubprogram *SP, DIE &SPDie) {
816  auto *SPDecl = SP->getDeclaration();
817  auto *Context = resolve(SPDecl ? SPDecl->getScope() : SP->getScope());
818  applySubprogramAttributes(SP, SPDie, includeMinimalInlineScopes());
819  addGlobalName(SP->getName(), SPDie, Context);
820}
821
822bool DwarfCompileUnit::isDwoUnit() const {
823  return DD->useSplitDwarf() && Skeleton;
824}
825
826bool DwarfCompileUnit::includeMinimalInlineScopes() const {
827  return getCUNode()->getEmissionKind() == DIBuilder::LineTablesOnly ||
828         (DD->useSplitDwarf() && !Skeleton);
829}
830} // end llvm namespace
831