lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

   1 //===- llvm/CodeGen/DwarfCompileUnit.cpp - Dwarf Compile Units ------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file contains support for constructing a dwarf compile unit.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "DwarfCompileUnit.h"
  14 #include "AddressPool.h"
  15 #include "DwarfDebug.h"
  16 #include "DwarfExpression.h"
  17 #include "DwarfUnit.h"
  18 #include "llvm/ADT/None.h"
  19 #include "llvm/ADT/STLExtras.h"
  20 #include "llvm/ADT/SmallString.h"
  21 #include "llvm/ADT/SmallVector.h"
  22 #include "llvm/ADT/StringRef.h"
  23 #include "llvm/BinaryFormat/Dwarf.h"
  24 #include "llvm/CodeGen/AsmPrinter.h"
  25 #include "llvm/CodeGen/DIE.h"
  26 #include "llvm/CodeGen/LexicalScopes.h"
  27 #include "llvm/CodeGen/MachineFunction.h"
  28 #include "llvm/CodeGen/MachineInstr.h"
  29 #include "llvm/CodeGen/MachineOperand.h"
  30 #include "llvm/CodeGen/TargetFrameLowering.h"
  31 #include "llvm/CodeGen/TargetRegisterInfo.h"
  32 #include "llvm/CodeGen/TargetSubtargetInfo.h"
  33 #include "llvm/IR/DataLayout.h"
  34 #include "llvm/IR/DebugInfo.h"
  35 #include "llvm/IR/DebugInfoMetadata.h"
  36 #include "llvm/IR/GlobalVariable.h"
  37 #include "llvm/MC/MCSection.h"
  38 #include "llvm/MC/MCStreamer.h"
  39 #include "llvm/MC/MCSymbol.h"
  40 #include "llvm/MC/MachineLocation.h"
  41 #include "llvm/Support/Casting.h"
  42 #include "llvm/Target/TargetLoweringObjectFile.h"
  43 #include "llvm/Target/TargetMachine.h"
  44 #include "llvm/Target/TargetOptions.h"
  45 #include <algorithm>
  46 #include <cassert>
  47 #include <cstdint>
  48 #include <iterator>
  49 #include <memory>
  50 #include <string>
  51 #include <utility>
  52
  53 using namespace llvm;
  54
  55 DwarfCompileUnit::DwarfCompileUnit(unsigned UID, const DICompileUnit *Node,
  56                                    AsmPrinter *A, DwarfDebug *DW,
  57                                    DwarfFile *DWU)
  58     : DwarfUnit(dwarf::DW_TAG_compile_unit, Node, A, DW, DWU), UniqueID(UID) {
  59   insertDIE(Node, &getUnitDie());
  60   MacroLabelBegin = Asm->createTempSymbol("cu_macro_begin");
  61 }
  62
  63 /// addLabelAddress - Add a dwarf label attribute data and value using
  64 /// DW_FORM_addr or DW_FORM_GNU_addr_index.
  65 void DwarfCompileUnit::addLabelAddress(DIE &Die, dwarf::Attribute Attribute,
  66                                        const MCSymbol *Label) {
  67   // Don't use the address pool in non-fission or in the skeleton unit itself.
  68   // FIXME: Once GDB supports this, it's probably worthwhile using the address
  69   // pool from the skeleton - maybe even in non-fission (possibly fewer
  70   // relocations by sharing them in the pool, but we have other ideas about how
  71   // to reduce the number of relocations as well/instead).
  72   if ((!DD->useSplitDwarf() || !Skeleton) && DD->getDwarfVersion() < 5)
  73     return addLocalLabelAddress(Die, Attribute, Label);
  74
  75   if (Label)
  76     DD->addArangeLabel(SymbolCU(this, Label));
  77
  78   unsigned idx = DD->getAddressPool().getIndex(Label);
  79   Die.addValue(DIEValueAllocator, Attribute,
  80                DD->getDwarfVersion() >= 5 ? dwarf::DW_FORM_addrx
  81                                           : dwarf::DW_FORM_GNU_addr_index,
  82                DIEInteger(idx));
  83 }
  84
  85 void DwarfCompileUnit::addLocalLabelAddress(DIE &Die,
  86                                             dwarf::Attribute Attribute,
  87                                             const MCSymbol *Label) {
  88   if (Label)
  89     DD->addArangeLabel(SymbolCU(this, Label));
  90
  91   if (Label)
  92     Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_addr,
  93                  DIELabel(Label));
  94   else
  95     Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_addr,
  96                  DIEInteger(0));
  97 }
  98
  99 unsigned DwarfCompileUnit::getOrCreateSourceID(const DIFile *File) {
 100   // If we print assembly, we can't separate .file entries according to
 101   // compile units. Thus all files will belong to the default compile unit.
 102
 103   // FIXME: add a better feature test than hasRawTextSupport. Even better,
 104   // extend .file to support this.
 105   unsigned CUID = Asm->OutStreamer->hasRawTextSupport() ? 0 : getUniqueID();
 106   if (!File)
 107     return Asm->OutStreamer->EmitDwarfFileDirective(0, "", "", None, None, CUID);
 108   return Asm->OutStreamer->EmitDwarfFileDirective(
 109       0, File->getDirectory(), File->getFilename(), getMD5AsBytes(File),
 110       File->getSource(), CUID);
 111 }
 112
 113 DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(
 114     const DIGlobalVariable *GV, ArrayRef<GlobalExpr> GlobalExprs) {
 115   // Check for pre-existence.
 116   if (DIE *Die = getDIE(GV))
 117     return Die;
 118
 119   assert(GV);
 120
 121   auto *GVContext = GV->getScope();
 122   const DIType *GTy = GV->getType();
 123
 124   // Construct the context before querying for the existence of the DIE in
 125   // case such construction creates the DIE.
 126   auto *CB = GVContext ? dyn_cast<DICommonBlock>(GVContext) : nullptr;
 127   DIE *ContextDIE = CB ? getOrCreateCommonBlock(CB, GlobalExprs)
 128     : getOrCreateContextDIE(GVContext);
 129
 130   // Add to map.
 131   DIE *VariableDIE = &createAndAddDIE(GV->getTag(), *ContextDIE, GV);
 132   DIScope *DeclContext;
 133   if (auto *SDMDecl = GV->getStaticDataMemberDeclaration()) {
 134     DeclContext = SDMDecl->getScope();
 135     assert(SDMDecl->isStaticMember() && "Expected static member decl");
 136     assert(GV->isDefinition());
 137     // We need the declaration DIE that is in the static member's class.
 138     DIE *VariableSpecDIE = getOrCreateStaticMemberDIE(SDMDecl);
 139     addDIEEntry(*VariableDIE, dwarf::DW_AT_specification, *VariableSpecDIE);
 140     // If the global variable's type is different from the one in the class
 141     // member type, assume that it's more specific and also emit it.
 142     if (GTy != SDMDecl->getBaseType())
 143       addType(*VariableDIE, GTy);
 144   } else {
 145     DeclContext = GV->getScope();
 146     // Add name and type.
 147     addString(*VariableDIE, dwarf::DW_AT_name, GV->getDisplayName());
 148     addType(*VariableDIE, GTy);
 149
 150     // Add scoping info.
 151     if (!GV->isLocalToUnit())
 152       addFlag(*VariableDIE, dwarf::DW_AT_external);
 153
 154     // Add line number info.
 155     addSourceLine(*VariableDIE, GV);
 156   }
 157
 158   if (!GV->isDefinition())
 159     addFlag(*VariableDIE, dwarf::DW_AT_declaration);
 160   else
 161     addGlobalName(GV->getName(), *VariableDIE, DeclContext);
 162
 163   if (uint32_t AlignInBytes = GV->getAlignInBytes())
 164     addUInt(*VariableDIE, dwarf::DW_AT_alignment, dwarf::DW_FORM_udata,
 165             AlignInBytes);
 166
 167   if (MDTuple *TP = GV->getTemplateParams())
 168     addTemplateParams(*VariableDIE, DINodeArray(TP));
 169
 170   // Add location.
 171   addLocationAttribute(VariableDIE, GV, GlobalExprs);
 172
 173   return VariableDIE;
 174 }
 175
 176 void DwarfCompileUnit::addLocationAttribute(
 177     DIE *VariableDIE, const DIGlobalVariable *GV, ArrayRef<GlobalExpr> GlobalExprs) {
 178   bool addToAccelTable = false;
 179   DIELoc *Loc = nullptr;
 180   Optional<unsigned> NVPTXAddressSpace;
 181   std::unique_ptr<DIEDwarfExpression> DwarfExpr;
 182   for (const auto &GE : GlobalExprs) {
 183     const GlobalVariable *Global = GE.Var;
 184     const DIExpression *Expr = GE.Expr;
 185
 186     // For compatibility with DWARF 3 and earlier,
 187     // DW_AT_location(DW_OP_constu, X, DW_OP_stack_value) becomes
 188     // DW_AT_const_value(X).
 189     if (GlobalExprs.size() == 1 && Expr && Expr->isConstant()) {
 190       addToAccelTable = true;
 191       addConstantValue(*VariableDIE, /*Unsigned=*/true, Expr->getElement(1));
 192       break;
 193     }
 194
 195     // We cannot describe the location of dllimport'd variables: the
 196     // computation of their address requires loads from the IAT.
 197     if (Global && Global->hasDLLImportStorageClass())
 198       continue;
 199
 200     // Nothing to describe without address or constant.
 201     if (!Global && (!Expr || !Expr->isConstant()))
 202       continue;
 203
 204     if (Global && Global->isThreadLocal() &&
 205         !Asm->getObjFileLowering().supportDebugThreadLocalLocation())
 206       continue;
 207
 208     if (!Loc) {
 209       addToAccelTable = true;
 210       Loc = new (DIEValueAllocator) DIELoc;
 211       DwarfExpr = std::make_unique<DIEDwarfExpression>(*Asm, *this, *Loc);
 212     }
 213
 214     if (Expr) {
 215       // According to
 216       // https://docs.nvidia.com/cuda/archive/10.0/ptx-writers-guide-to-interoperability/index.html#cuda-specific-dwarf
 217       // cuda-gdb requires DW_AT_address_class for all variables to be able to
 218       // correctly interpret address space of the variable address.
 219       // Decode DW_OP_constu <DWARF Address Space> DW_OP_swap DW_OP_xderef
 220       // sequence for the NVPTX + gdb target.
 221       unsigned LocalNVPTXAddressSpace;
 222       if (Asm->TM.getTargetTriple().isNVPTX() && DD->tuneForGDB()) {
 223         const DIExpression *NewExpr =
 224             DIExpression::extractAddressClass(Expr, LocalNVPTXAddressSpace);
 225         if (NewExpr != Expr) {
 226           Expr = NewExpr;
 227           NVPTXAddressSpace = LocalNVPTXAddressSpace;
 228         }
 229       }
 230       DwarfExpr->addFragmentOffset(Expr);
 231     }
 232
 233     if (Global) {
 234       const MCSymbol *Sym = Asm->getSymbol(Global);
 235       if (Global->isThreadLocal()) {
 236         if (Asm->TM.useEmulatedTLS()) {
 237           // TODO: add debug info for emulated thread local mode.
 238         } else {
 239           // FIXME: Make this work with -gsplit-dwarf.
 240           unsigned PointerSize = Asm->getDataLayout().getPointerSize();
 241           assert((PointerSize == 4 || PointerSize == 8) &&
 242                  "Add support for other sizes if necessary");
 243           // Based on GCC's support for TLS:
 244           if (!DD->useSplitDwarf()) {
 245             // 1) Start with a constNu of the appropriate pointer size
 246             addUInt(*Loc, dwarf::DW_FORM_data1,
 247                     PointerSize == 4 ? dwarf::DW_OP_const4u
 248                                      : dwarf::DW_OP_const8u);
 249             // 2) containing the (relocated) offset of the TLS variable
 250             //    within the module's TLS block.
 251             addExpr(*Loc, dwarf::DW_FORM_udata,
 252                     Asm->getObjFileLowering().getDebugThreadLocalSymbol(Sym));
 253           } else {
 254             addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_const_index);
 255             addUInt(*Loc, dwarf::DW_FORM_udata,
 256                     DD->getAddressPool().getIndex(Sym, /* TLS */ true));
 257           }
 258           // 3) followed by an OP to make the debugger do a TLS lookup.
 259           addUInt(*Loc, dwarf::DW_FORM_data1,
 260                   DD->useGNUTLSOpcode() ? dwarf::DW_OP_GNU_push_tls_address
 261                                         : dwarf::DW_OP_form_tls_address);
 262         }
 263       } else {
 264         DD->addArangeLabel(SymbolCU(this, Sym));
 265         addOpAddress(*Loc, Sym);
 266       }
 267     }
 268     // Global variables attached to symbols are memory locations.
 269     // It would be better if this were unconditional, but malformed input that
 270     // mixes non-fragments and fragments for the same variable is too expensive
 271     // to detect in the verifier.
 272     if (DwarfExpr->isUnknownLocation())
 273       DwarfExpr->setMemoryLocationKind();
 274     DwarfExpr->addExpression(Expr);
 275   }
 276   if (Asm->TM.getTargetTriple().isNVPTX() && DD->tuneForGDB()) {
 277     // According to
 278     // https://docs.nvidia.com/cuda/archive/10.0/ptx-writers-guide-to-interoperability/index.html#cuda-specific-dwarf
 279     // cuda-gdb requires DW_AT_address_class for all variables to be able to
 280     // correctly interpret address space of the variable address.
 281     const unsigned NVPTX_ADDR_global_space = 5;
 282     addUInt(*VariableDIE, dwarf::DW_AT_address_class, dwarf::DW_FORM_data1,
 283             NVPTXAddressSpace ? *NVPTXAddressSpace : NVPTX_ADDR_global_space);
 284   }
 285   if (Loc)
 286     addBlock(*VariableDIE, dwarf::DW_AT_location, DwarfExpr->finalize());
 287
 288   if (DD->useAllLinkageNames())
 289     addLinkageName(*VariableDIE, GV->getLinkageName());
 290
 291   if (addToAccelTable) {
 292     DD->addAccelName(*CUNode, GV->getName(), *VariableDIE);
 293
 294     // If the linkage name is different than the name, go ahead and output
 295     // that as well into the name table.
 296     if (GV->getLinkageName() != "" && GV->getName() != GV->getLinkageName() &&
 297         DD->useAllLinkageNames())
 298       DD->addAccelName(*CUNode, GV->getLinkageName(), *VariableDIE);
 299   }
 300 }
 301
 302 DIE *DwarfCompileUnit::getOrCreateCommonBlock(
 303     const DICommonBlock *CB, ArrayRef<GlobalExpr> GlobalExprs) {
 304   // Construct the context before querying for the existence of the DIE in case
 305   // such construction creates the DIE.
 306   DIE *ContextDIE = getOrCreateContextDIE(CB->getScope());
 307
 308   if (DIE *NDie = getDIE(CB))
 309     return NDie;
 310   DIE &NDie = createAndAddDIE(dwarf::DW_TAG_common_block, *ContextDIE, CB);
 311   StringRef Name = CB->getName().empty() ? "_BLNK_" : CB->getName();
 312   addString(NDie, dwarf::DW_AT_name, Name);
 313   addGlobalName(Name, NDie, CB->getScope());
 314   if (CB->getFile())
 315     addSourceLine(NDie, CB->getLineNo(), CB->getFile());
 316   if (DIGlobalVariable *V = CB->getDecl())
 317     getCU().addLocationAttribute(&NDie, V, GlobalExprs);
 318   return &NDie;
 319 }
 320
 321 void DwarfCompileUnit::addRange(RangeSpan Range) {
 322   bool SameAsPrevCU = this == DD->getPrevCU();
 323   DD->setPrevCU(this);
 324   // If we have no current ranges just add the range and return, otherwise,
 325   // check the current section and CU against the previous section and CU we
 326   // emitted into and the subprogram was contained within. If these are the
 327   // same then extend our current range, otherwise add this as a new range.
 328   if (CURanges.empty() || !SameAsPrevCU ||
 329       (&CURanges.back().getEnd()->getSection() !=
 330        &Range.getEnd()->getSection())) {
 331     CURanges.push_back(Range);
 332     DD->addSectionLabel(Range.getStart());
 333     return;
 334   }
 335
 336   CURanges.back().setEnd(Range.getEnd());
 337 }
 338
 339 void DwarfCompileUnit::initStmtList() {
 340   if (CUNode->isDebugDirectivesOnly())
 341     return;
 342
 343   // Define start line table label for each Compile Unit.
 344   MCSymbol *LineTableStartSym;
 345   const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
 346   if (DD->useSectionsAsReferences()) {
 347     LineTableStartSym = TLOF.getDwarfLineSection()->getBeginSymbol();
 348   } else {
 349     LineTableStartSym =
 350         Asm->OutStreamer->getDwarfLineTableSymbol(getUniqueID());
 351   }
 352
 353   // DW_AT_stmt_list is a offset of line number information for this
 354   // compile unit in debug_line section. For split dwarf this is
 355   // left in the skeleton CU and so not included.
 356   // The line table entries are not always emitted in assembly, so it
 357   // is not okay to use line_table_start here.
 358   StmtListValue =
 359       addSectionLabel(getUnitDie(), dwarf::DW_AT_stmt_list, LineTableStartSym,
 360                       TLOF.getDwarfLineSection()->getBeginSymbol());
 361 }
 362
 363 void DwarfCompileUnit::applyStmtList(DIE &D) {
 364   D.addValue(DIEValueAllocator, *StmtListValue);
 365 }
 366
 367 void DwarfCompileUnit::attachLowHighPC(DIE &D, const MCSymbol *Begin,
 368                                        const MCSymbol *End) {
 369   assert(Begin && "Begin label should not be null!");
 370   assert(End && "End label should not be null!");
 371   assert(Begin->isDefined() && "Invalid starting label");
 372   assert(End->isDefined() && "Invalid end label");
 373
 374   addLabelAddress(D, dwarf::DW_AT_low_pc, Begin);
 375   if (DD->getDwarfVersion() < 4)
 376     addLabelAddress(D, dwarf::DW_AT_high_pc, End);
 377   else
 378     addLabelDelta(D, dwarf::DW_AT_high_pc, End, Begin);
 379 }
 380
 381 // Find DIE for the given subprogram and attach appropriate DW_AT_low_pc
 382 // and DW_AT_high_pc attributes. If there are global variables in this
 383 // scope then create and insert DIEs for these variables.
 384 DIE &DwarfCompileUnit::updateSubprogramScopeDIE(const DISubprogram *SP) {
 385   DIE *SPDie = getOrCreateSubprogramDIE(SP, includeMinimalInlineScopes());
 386
 387   attachLowHighPC(*SPDie, Asm->getFunctionBegin(), Asm->getFunctionEnd());
 388   if (DD->useAppleExtensionAttributes() &&
 389       !DD->getCurrentFunction()->getTarget().Options.DisableFramePointerElim(
 390           *DD->getCurrentFunction()))
 391     addFlag(*SPDie, dwarf::DW_AT_APPLE_omit_frame_ptr);
 392
 393   // Only include DW_AT_frame_base in full debug info
 394   if (!includeMinimalInlineScopes()) {
 395     if (Asm->MF->getTarget().getTargetTriple().isNVPTX()) {
 396       DIELoc *Loc = new (DIEValueAllocator) DIELoc;
 397       addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_call_frame_cfa);
 398       addBlock(*SPDie, dwarf::DW_AT_frame_base, Loc);
 399     } else {
 400       const TargetRegisterInfo *RI = Asm->MF->getSubtarget().getRegisterInfo();
 401       MachineLocation Location(RI->getFrameRegister(*Asm->MF));
 402       if (Register::isPhysicalRegister(Location.getReg()))
 403         addAddress(*SPDie, dwarf::DW_AT_frame_base, Location);
 404     }
 405   }
 406
 407   // Add name to the name table, we do this here because we're guaranteed
 408   // to have concrete versions of our DW_TAG_subprogram nodes.
 409   DD->addSubprogramNames(*CUNode, SP, *SPDie);
 410
 411   return *SPDie;
 412 }
 413
 414 // Construct a DIE for this scope.
 415 void DwarfCompileUnit::constructScopeDIE(
 416     LexicalScope *Scope, SmallVectorImpl<DIE *> &FinalChildren) {
 417   if (!Scope || !Scope->getScopeNode())
 418     return;
 419
 420   auto *DS = Scope->getScopeNode();
 421
 422   assert((Scope->getInlinedAt() || !isa<DISubprogram>(DS)) &&
 423          "Only handle inlined subprograms here, use "
 424          "constructSubprogramScopeDIE for non-inlined "
 425          "subprograms");
 426
 427   SmallVector<DIE *, 8> Children;
 428
 429   // We try to create the scope DIE first, then the children DIEs. This will
 430   // avoid creating un-used children then removing them later when we find out
 431   // the scope DIE is null.
 432   DIE *ScopeDIE;
 433   if (Scope->getParent() && isa<DISubprogram>(DS)) {
 434     ScopeDIE = constructInlinedScopeDIE(Scope);
 435     if (!ScopeDIE)
 436       return;
 437     // We create children when the scope DIE is not null.
 438     createScopeChildrenDIE(Scope, Children);
 439   } else {
 440     // Early exit when we know the scope DIE is going to be null.
 441     if (DD->isLexicalScopeDIENull(Scope))
 442       return;
 443
 444     bool HasNonScopeChildren = false;
 445
 446     // We create children here when we know the scope DIE is not going to be
 447     // null and the children will be added to the scope DIE.
 448     createScopeChildrenDIE(Scope, Children, &HasNonScopeChildren);
 449
 450     // If there are only other scopes as children, put them directly in the
 451     // parent instead, as this scope would serve no purpose.
 452     if (!HasNonScopeChildren) {
 453       FinalChildren.insert(FinalChildren.end(),
 454                            std::make_move_iterator(Children.begin()),
 455                            std::make_move_iterator(Children.end()));
 456       return;
 457     }
 458     ScopeDIE = constructLexicalScopeDIE(Scope);
 459     assert(ScopeDIE && "Scope DIE should not be null.");
 460   }
 461
 462   // Add children
 463   for (auto &I : Children)
 464     ScopeDIE->addChild(std::move(I));
 465
 466   FinalChildren.push_back(std::move(ScopeDIE));
 467 }
 468
 469 void DwarfCompileUnit::addScopeRangeList(DIE &ScopeDIE,
 470                                          SmallVector<RangeSpan, 2> Range) {
 471   const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
 472
 473   // Emit the offset into .debug_ranges or .debug_rnglists as a relocatable
 474   // label. emitDIE() will handle emitting it appropriately.
 475   const MCSymbol *RangeSectionSym =
 476       DD->getDwarfVersion() >= 5
 477           ? TLOF.getDwarfRnglistsSection()->getBeginSymbol()
 478           : TLOF.getDwarfRangesSection()->getBeginSymbol();
 479
 480   HasRangeLists = true;
 481
 482   // Add the range list to the set of ranges to be emitted.
 483   auto IndexAndList =
 484       (DD->getDwarfVersion() < 5 && Skeleton ? Skeleton->DU : DU)
 485           ->addRange(*(Skeleton ? Skeleton : this), std::move(Range));
 486
 487   uint32_t Index = IndexAndList.first;
 488   auto &List = *IndexAndList.second;
 489
 490   // Under fission, ranges are specified by constant offsets relative to the
 491   // CU's DW_AT_GNU_ranges_base.
 492   // FIXME: For DWARF v5, do not generate the DW_AT_ranges attribute under
 493   // fission until we support the forms using the .debug_addr section
 494   // (DW_RLE_startx_endx etc.).
 495   if (DD->getDwarfVersion() >= 5)
 496     addUInt(ScopeDIE, dwarf::DW_AT_ranges, dwarf::DW_FORM_rnglistx, Index);
 497   else if (isDwoUnit())
 498     addSectionDelta(ScopeDIE, dwarf::DW_AT_ranges, List.getSym(),
 499                     RangeSectionSym);
 500   else
 501     addSectionLabel(ScopeDIE, dwarf::DW_AT_ranges, List.getSym(),
 502                     RangeSectionSym);
 503 }
 504
 505 void DwarfCompileUnit::attachRangesOrLowHighPC(
 506     DIE &Die, SmallVector<RangeSpan, 2> Ranges) {
 507   if (Ranges.size() == 1 || !DD->useRangesSection()) {
 508     const RangeSpan &Front = Ranges.front();
 509     const RangeSpan &Back = Ranges.back();
 510     attachLowHighPC(Die, Front.getStart(), Back.getEnd());
 511   } else
 512     addScopeRangeList(Die, std::move(Ranges));
 513 }
 514
 515 void DwarfCompileUnit::attachRangesOrLowHighPC(
 516     DIE &Die, const SmallVectorImpl<InsnRange> &Ranges) {
 517   SmallVector<RangeSpan, 2> List;
 518   List.reserve(Ranges.size());
 519   for (const InsnRange &R : Ranges)
 520     List.push_back(RangeSpan(DD->getLabelBeforeInsn(R.first),
 521                              DD->getLabelAfterInsn(R.second)));
 522   attachRangesOrLowHighPC(Die, std::move(List));
 523 }
 524
 525 // This scope represents inlined body of a function. Construct DIE to
 526 // represent this concrete inlined copy of the function.
 527 DIE *DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope) {
 528   assert(Scope->getScopeNode());
 529   auto *DS = Scope->getScopeNode();
 530   auto *InlinedSP = getDISubprogram(DS);
 531   // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
 532   // was inlined from another compile unit.
 533   DIE *OriginDIE = getAbstractSPDies()[InlinedSP];
 534   assert(OriginDIE && "Unable to find original DIE for an inlined subprogram.");
 535
 536   auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_inlined_subroutine);
 537   addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *OriginDIE);
 538
 539   attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
 540
 541   // Add the call site information to the DIE.
 542   const DILocation *IA = Scope->getInlinedAt();
 543   addUInt(*ScopeDIE, dwarf::DW_AT_call_file, None,
 544           getOrCreateSourceID(IA->getFile()));
 545   addUInt(*ScopeDIE, dwarf::DW_AT_call_line, None, IA->getLine());
 546   if (IA->getColumn())
 547     addUInt(*ScopeDIE, dwarf::DW_AT_call_column, None, IA->getColumn());
 548   if (IA->getDiscriminator() && DD->getDwarfVersion() >= 4)
 549     addUInt(*ScopeDIE, dwarf::DW_AT_GNU_discriminator, None,
 550             IA->getDiscriminator());
 551
 552   // Add name to the name table, we do this here because we're guaranteed
 553   // to have concrete versions of our DW_TAG_inlined_subprogram nodes.
 554   DD->addSubprogramNames(*CUNode, InlinedSP, *ScopeDIE);
 555
 556   return ScopeDIE;
 557 }
 558
 559 // Construct new DW_TAG_lexical_block for this scope and attach
 560 // DW_AT_low_pc/DW_AT_high_pc labels.
 561 DIE *DwarfCompileUnit::constructLexicalScopeDIE(LexicalScope *Scope) {
 562   if (DD->isLexicalScopeDIENull(Scope))
 563     return nullptr;
 564
 565   auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_lexical_block);
 566   if (Scope->isAbstractScope())
 567     return ScopeDIE;
 568
 569   attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());
 570
 571   return ScopeDIE;
 572 }
 573
 574 /// constructVariableDIE - Construct a DIE for the given DbgVariable.
 575 DIE *DwarfCompileUnit::constructVariableDIE(DbgVariable &DV, bool Abstract) {
 576   auto D = constructVariableDIEImpl(DV, Abstract);
 577   DV.setDIE(*D);
 578   return D;
 579 }
 580
 581 DIE *DwarfCompileUnit::constructLabelDIE(DbgLabel &DL,
 582                                          const LexicalScope &Scope) {
 583   auto LabelDie = DIE::get(DIEValueAllocator, DL.getTag());
 584   insertDIE(DL.getLabel(), LabelDie);
 585   DL.setDIE(*LabelDie);
 586
 587   if (Scope.isAbstractScope())
 588     applyLabelAttributes(DL, *LabelDie);
 589
 590   return LabelDie;
 591 }
 592
 593 DIE *DwarfCompileUnit::constructVariableDIEImpl(const DbgVariable &DV,
 594                                                 bool Abstract) {
 595   // Define variable debug information entry.
 596   auto VariableDie = DIE::get(DIEValueAllocator, DV.getTag());
 597   insertDIE(DV.getVariable(), VariableDie);
 598
 599   if (Abstract) {
 600     applyVariableAttributes(DV, *VariableDie);
 601     return VariableDie;
 602   }
 603
 604   // Add variable address.
 605
 606   unsigned Offset = DV.getDebugLocListIndex();
 607   if (Offset != ~0U) {
 608     addLocationList(*VariableDie, dwarf::DW_AT_location, Offset);
 609     return VariableDie;
 610   }
 611
 612   // Check if variable has a single location description.
 613   if (auto *DVal = DV.getValueLoc()) {
 614     if (DVal->isLocation())
 615       addVariableAddress(DV, *VariableDie, DVal->getLoc());
 616     else if (DVal->isInt()) {
 617       auto *Expr = DV.getSingleExpression();
 618       if (Expr && Expr->getNumElements()) {
 619         DIELoc *Loc = new (DIEValueAllocator) DIELoc;
 620         DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
 621         // If there is an expression, emit raw unsigned bytes.
 622         DwarfExpr.addFragmentOffset(Expr);
 623         DwarfExpr.addUnsignedConstant(DVal->getInt());
 624         DwarfExpr.addExpression(Expr);
 625         addBlock(*VariableDie, dwarf::DW_AT_location, DwarfExpr.finalize());
 626       } else
 627         addConstantValue(*VariableDie, DVal->getInt(), DV.getType());
 628     } else if (DVal->isConstantFP()) {
 629       addConstantFPValue(*VariableDie, DVal->getConstantFP());
 630     } else if (DVal->isConstantInt()) {
 631       addConstantValue(*VariableDie, DVal->getConstantInt(), DV.getType());
 632     }
 633     return VariableDie;
 634   }
 635
 636   // .. else use frame index.
 637   if (!DV.hasFrameIndexExprs())
 638     return VariableDie;
 639
 640   Optional<unsigned> NVPTXAddressSpace;
 641   DIELoc *Loc = new (DIEValueAllocator) DIELoc;
 642   DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
 643   for (auto &Fragment : DV.getFrameIndexExprs()) {
 644     unsigned FrameReg = 0;
 645     const DIExpression *Expr = Fragment.Expr;
 646     const TargetFrameLowering *TFI = Asm->MF->getSubtarget().getFrameLowering();
 647     int Offset = TFI->getFrameIndexReference(*Asm->MF, Fragment.FI, FrameReg);
 648     DwarfExpr.addFragmentOffset(Expr);
 649     SmallVector<uint64_t, 8> Ops;
 650     DIExpression::appendOffset(Ops, Offset);
 651     // According to
 652     // https://docs.nvidia.com/cuda/archive/10.0/ptx-writers-guide-to-interoperability/index.html#cuda-specific-dwarf
 653     // cuda-gdb requires DW_AT_address_class for all variables to be able to
 654     // correctly interpret address space of the variable address.
 655     // Decode DW_OP_constu <DWARF Address Space> DW_OP_swap DW_OP_xderef
 656     // sequence for the NVPTX + gdb target.
 657     unsigned LocalNVPTXAddressSpace;
 658     if (Asm->TM.getTargetTriple().isNVPTX() && DD->tuneForGDB()) {
 659       const DIExpression *NewExpr =
 660           DIExpression::extractAddressClass(Expr, LocalNVPTXAddressSpace);
 661       if (NewExpr != Expr) {
 662         Expr = NewExpr;
 663         NVPTXAddressSpace = LocalNVPTXAddressSpace;
 664       }
 665     }
 666     if (Expr)
 667       Ops.append(Expr->elements_begin(), Expr->elements_end());
 668     DIExpressionCursor Cursor(Ops);
 669     DwarfExpr.setMemoryLocationKind();
 670     if (const MCSymbol *FrameSymbol = Asm->getFunctionFrameSymbol())
 671       addOpAddress(*Loc, FrameSymbol);
 672     else
 673       DwarfExpr.addMachineRegExpression(
 674           *Asm->MF->getSubtarget().getRegisterInfo(), Cursor, FrameReg);
 675     DwarfExpr.addExpression(std::move(Cursor));
 676   }
 677   if (Asm->TM.getTargetTriple().isNVPTX() && DD->tuneForGDB()) {
 678     // According to
 679     // https://docs.nvidia.com/cuda/archive/10.0/ptx-writers-guide-to-interoperability/index.html#cuda-specific-dwarf
 680     // cuda-gdb requires DW_AT_address_class for all variables to be able to
 681     // correctly interpret address space of the variable address.
 682     const unsigned NVPTX_ADDR_local_space = 6;
 683     addUInt(*VariableDie, dwarf::DW_AT_address_class, dwarf::DW_FORM_data1,
 684             NVPTXAddressSpace ? *NVPTXAddressSpace : NVPTX_ADDR_local_space);
 685   }
 686   addBlock(*VariableDie, dwarf::DW_AT_location, DwarfExpr.finalize());
 687   if (DwarfExpr.TagOffset)
 688     addUInt(*VariableDie, dwarf::DW_AT_LLVM_tag_offset, dwarf::DW_FORM_data1,
 689             *DwarfExpr.TagOffset);
 690
 691   return VariableDie;
 692 }
 693
 694 DIE *DwarfCompileUnit::constructVariableDIE(DbgVariable &DV,
 695                                             const LexicalScope &Scope,
 696                                             DIE *&ObjectPointer) {
 697   auto Var = constructVariableDIE(DV, Scope.isAbstractScope());
 698   if (DV.isObjectPointer())
 699     ObjectPointer = Var;
 700   return Var;
 701 }
 702
 703 /// Return all DIVariables that appear in count: expressions.
 704 static SmallVector<const DIVariable *, 2> dependencies(DbgVariable *Var) {
 705   SmallVector<const DIVariable *, 2> Result;
 706   auto *Array = dyn_cast<DICompositeType>(Var->getType());
 707   if (!Array || Array->getTag() != dwarf::DW_TAG_array_type)
 708     return Result;
 709   for (auto *El : Array->getElements()) {
 710     if (auto *Subrange = dyn_cast<DISubrange>(El)) {
 711       auto Count = Subrange->getCount();
 712       if (auto *Dependency = Count.dyn_cast<DIVariable *>())
 713         Result.push_back(Dependency);
 714     }
 715   }
 716   return Result;
 717 }
 718
 719 /// Sort local variables so that variables appearing inside of helper
 720 /// expressions come first.
 721 static SmallVector<DbgVariable *, 8>
 722 sortLocalVars(SmallVectorImpl<DbgVariable *> &Input) {
 723   SmallVector<DbgVariable *, 8> Result;
 724   SmallVector<PointerIntPair<DbgVariable *, 1>, 8> WorkList;
 725   // Map back from a DIVariable to its containing DbgVariable.
 726   SmallDenseMap<const DILocalVariable *, DbgVariable *> DbgVar;
 727   // Set of DbgVariables in Result.
 728   SmallDenseSet<DbgVariable *, 8> Visited;
 729   // For cycle detection.
 730   SmallDenseSet<DbgVariable *, 8> Visiting;
 731
 732   // Initialize the worklist and the DIVariable lookup table.
 733   for (auto Var : reverse(Input)) {
 734     DbgVar.insert({Var->getVariable(), Var});
 735     WorkList.push_back({Var, 0});
 736   }
 737
 738   // Perform a stable topological sort by doing a DFS.
 739   while (!WorkList.empty()) {
 740     auto Item = WorkList.back();
 741     DbgVariable *Var = Item.getPointer();
 742     bool visitedAllDependencies = Item.getInt();
 743     WorkList.pop_back();
 744
 745     // Dependency is in a different lexical scope or a global.
 746     if (!Var)
 747       continue;
 748
 749     // Already handled.
 750     if (Visited.count(Var))
 751       continue;
 752
 753     // Add to Result if all dependencies are visited.
 754     if (visitedAllDependencies) {
 755       Visited.insert(Var);
 756       Result.push_back(Var);
 757       continue;
 758     }
 759
 760     // Detect cycles.
 761     auto Res = Visiting.insert(Var);
 762     if (!Res.second) {
 763       assert(false && "dependency cycle in local variables");
 764       return Result;
 765     }
 766
 767     // Push dependencies and this node onto the worklist, so that this node is
 768     // visited again after all of its dependencies are handled.
 769     WorkList.push_back({Var, 1});
 770     for (auto *Dependency : dependencies(Var)) {
 771       auto Dep = dyn_cast_or_null<const DILocalVariable>(Dependency);
 772       WorkList.push_back({DbgVar[Dep], 0});
 773     }
 774   }
 775   return Result;
 776 }
 777
 778 DIE *DwarfCompileUnit::createScopeChildrenDIE(LexicalScope *Scope,
 779                                               SmallVectorImpl<DIE *> &Children,
 780                                               bool *HasNonScopeChildren) {
 781   assert(Children.empty());
 782   DIE *ObjectPointer = nullptr;
 783
 784   // Emit function arguments (order is significant).
 785   auto Vars = DU->getScopeVariables().lookup(Scope);
 786   for (auto &DV : Vars.Args)
 787     Children.push_back(constructVariableDIE(*DV.second, *Scope, ObjectPointer));
 788
 789   // Emit local variables.
 790   auto Locals = sortLocalVars(Vars.Locals);
 791   for (DbgVariable *DV : Locals)
 792     Children.push_back(constructVariableDIE(*DV, *Scope, ObjectPointer));
 793
 794   // Skip imported directives in gmlt-like data.
 795   if (!includeMinimalInlineScopes()) {
 796     // There is no need to emit empty lexical block DIE.
 797     for (const auto *IE : ImportedEntities[Scope->getScopeNode()])
 798       Children.push_back(
 799           constructImportedEntityDIE(cast<DIImportedEntity>(IE)));
 800   }
 801
 802   if (HasNonScopeChildren)
 803     *HasNonScopeChildren = !Children.empty();
 804
 805   for (DbgLabel *DL : DU->getScopeLabels().lookup(Scope))
 806     Children.push_back(constructLabelDIE(*DL, *Scope));
 807
 808   for (LexicalScope *LS : Scope->getChildren())
 809     constructScopeDIE(LS, Children);
 810
 811   return ObjectPointer;
 812 }
 813
 814 DIE &DwarfCompileUnit::constructSubprogramScopeDIE(const DISubprogram *Sub,
 815                                                    LexicalScope *Scope) {
 816   DIE &ScopeDIE = updateSubprogramScopeDIE(Sub);
 817
 818   if (Scope) {
 819     assert(!Scope->getInlinedAt());
 820     assert(!Scope->isAbstractScope());
 821     // Collect lexical scope children first.
 822     // ObjectPointer might be a local (non-argument) local variable if it's a
 823     // block's synthetic this pointer.
 824     if (DIE *ObjectPointer = createAndAddScopeChildren(Scope, ScopeDIE))
 825       addDIEEntry(ScopeDIE, dwarf::DW_AT_object_pointer, *ObjectPointer);
 826   }
 827
 828   // If this is a variadic function, add an unspecified parameter.
 829   DITypeRefArray FnArgs = Sub->getType()->getTypeArray();
 830
 831   // If we have a single element of null, it is a function that returns void.
 832   // If we have more than one elements and the last one is null, it is a
 833   // variadic function.
 834   if (FnArgs.size() > 1 && !FnArgs[FnArgs.size() - 1] &&
 835       !includeMinimalInlineScopes())
 836     ScopeDIE.addChild(
 837         DIE::get(DIEValueAllocator, dwarf::DW_TAG_unspecified_parameters));
 838
 839   return ScopeDIE;
 840 }
 841
 842 DIE *DwarfCompileUnit::createAndAddScopeChildren(LexicalScope *Scope,
 843                                                  DIE &ScopeDIE) {
 844   // We create children when the scope DIE is not null.
 845   SmallVector<DIE *, 8> Children;
 846   DIE *ObjectPointer = createScopeChildrenDIE(Scope, Children);
 847
 848   // Add children
 849   for (auto &I : Children)
 850     ScopeDIE.addChild(std::move(I));
 851
 852   return ObjectPointer;
 853 }
 854
 855 void DwarfCompileUnit::constructAbstractSubprogramScopeDIE(
 856     LexicalScope *Scope) {
 857   DIE *&AbsDef = getAbstractSPDies()[Scope->getScopeNode()];
 858   if (AbsDef)
 859     return;
 860
 861   auto *SP = cast<DISubprogram>(Scope->getScopeNode());
 862
 863   DIE *ContextDIE;
 864   DwarfCompileUnit *ContextCU = this;
 865
 866   if (includeMinimalInlineScopes())
 867     ContextDIE = &getUnitDie();
 868   // Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
 869   // the important distinction that the debug node is not associated with the
 870   // DIE (since the debug node will be associated with the concrete DIE, if
 871   // any). It could be refactored to some common utility function.
 872   else if (auto *SPDecl = SP->getDeclaration()) {
 873     ContextDIE = &getUnitDie();
 874     getOrCreateSubprogramDIE(SPDecl);
 875   } else {
 876     ContextDIE = getOrCreateContextDIE(SP->getScope());
 877     // The scope may be shared with a subprogram that has already been
 878     // constructed in another CU, in which case we need to construct this
 879     // subprogram in the same CU.
 880     ContextCU = DD->lookupCU(ContextDIE->getUnitDie());
 881   }
 882
 883   // Passing null as the associated node because the abstract definition
 884   // shouldn't be found by lookup.
 885   AbsDef = &ContextCU->createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE, nullptr);
 886   ContextCU->applySubprogramAttributesToDefinition(SP, *AbsDef);
 887
 888   if (!ContextCU->includeMinimalInlineScopes())
 889     ContextCU->addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
 890   if (DIE *ObjectPointer = ContextCU->createAndAddScopeChildren(Scope, *AbsDef))
 891     ContextCU->addDIEEntry(*AbsDef, dwarf::DW_AT_object_pointer, *ObjectPointer);
 892 }
 893
 894 /// Whether to use the GNU analog for a DWARF5 tag, attribute, or location atom.
 895 static bool useGNUAnalogForDwarf5Feature(DwarfDebug *DD) {
 896   return DD->getDwarfVersion() == 4 && DD->tuneForGDB();
 897 }
 898
 899 dwarf::Tag DwarfCompileUnit::getDwarf5OrGNUTag(dwarf::Tag Tag) const {
 900   if (!useGNUAnalogForDwarf5Feature(DD))
 901     return Tag;
 902   switch (Tag) {
 903   case dwarf::DW_TAG_call_site:
 904     return dwarf::DW_TAG_GNU_call_site;
 905   case dwarf::DW_TAG_call_site_parameter:
 906     return dwarf::DW_TAG_GNU_call_site_parameter;
 907   default:
 908     llvm_unreachable("DWARF5 tag with no GNU analog");
 909   }
 910 }
 911
 912 dwarf::Attribute
 913 DwarfCompileUnit::getDwarf5OrGNUAttr(dwarf::Attribute Attr) const {
 914   if (!useGNUAnalogForDwarf5Feature(DD))
 915     return Attr;
 916   switch (Attr) {
 917   case dwarf::DW_AT_call_all_calls:
 918     return dwarf::DW_AT_GNU_all_call_sites;
 919   case dwarf::DW_AT_call_target:
 920     return dwarf::DW_AT_GNU_call_site_target;
 921   case dwarf::DW_AT_call_origin:
 922     return dwarf::DW_AT_abstract_origin;
 923   case dwarf::DW_AT_call_pc:
 924     return dwarf::DW_AT_low_pc;
 925   case dwarf::DW_AT_call_value:
 926     return dwarf::DW_AT_GNU_call_site_value;
 927   case dwarf::DW_AT_call_tail_call:
 928     return dwarf::DW_AT_GNU_tail_call;
 929   default:
 930     llvm_unreachable("DWARF5 attribute with no GNU analog");
 931   }
 932 }
 933
 934 dwarf::LocationAtom
 935 DwarfCompileUnit::getDwarf5OrGNULocationAtom(dwarf::LocationAtom Loc) const {
 936   if (!useGNUAnalogForDwarf5Feature(DD))
 937     return Loc;
 938   switch (Loc) {
 939   case dwarf::DW_OP_entry_value:
 940     return dwarf::DW_OP_GNU_entry_value;
 941   default:
 942     llvm_unreachable("DWARF5 location atom with no GNU analog");
 943   }
 944 }
 945
 946 DIE &DwarfCompileUnit::constructCallSiteEntryDIE(
 947     DIE &ScopeDIE, const DISubprogram *CalleeSP, bool IsTail,
 948     const MCSymbol *PCAddr, const MCExpr *PCOffset, unsigned CallReg) {
 949   // Insert a call site entry DIE within ScopeDIE.
 950   DIE &CallSiteDIE = createAndAddDIE(getDwarf5OrGNUTag(dwarf::DW_TAG_call_site),
 951                                      ScopeDIE, nullptr);
 952
 953   if (CallReg) {
 954     // Indirect call.
 955     addAddress(CallSiteDIE, getDwarf5OrGNUAttr(dwarf::DW_AT_call_target),
 956                MachineLocation(CallReg));
 957   } else {
 958     DIE *CalleeDIE = getOrCreateSubprogramDIE(CalleeSP);
 959     assert(CalleeDIE && "Could not create DIE for call site entry origin");
 960     addDIEEntry(CallSiteDIE, getDwarf5OrGNUAttr(dwarf::DW_AT_call_origin),
 961                 *CalleeDIE);
 962   }
 963
 964   if (IsTail)
 965     // Attach DW_AT_call_tail_call to tail calls for standards compliance.
 966     addFlag(CallSiteDIE, getDwarf5OrGNUAttr(dwarf::DW_AT_call_tail_call));
 967
 968   // Attach the return PC to allow the debugger to disambiguate call paths
 969   // from one function to another.
 970   if (DD->getDwarfVersion() == 4 && DD->tuneForGDB()) {
 971     assert(PCAddr && "Missing PC information for a call");
 972     addLabelAddress(CallSiteDIE, dwarf::DW_AT_low_pc, PCAddr);
 973   } else if (!IsTail || DD->tuneForGDB()) {
 974     assert(PCOffset && "Missing return PC information for a call");
 975     addAddressExpr(CallSiteDIE, dwarf::DW_AT_call_return_pc, PCOffset);
 976   }
 977
 978   return CallSiteDIE;
 979 }
 980
 981 void DwarfCompileUnit::constructCallSiteParmEntryDIEs(
 982     DIE &CallSiteDIE, SmallVector<DbgCallSiteParam, 4> &Params) {
 983   for (const auto &Param : Params) {
 984     unsigned Register = Param.getRegister();
 985     auto CallSiteDieParam =
 986         DIE::get(DIEValueAllocator,
 987                  getDwarf5OrGNUTag(dwarf::DW_TAG_call_site_parameter));
 988     insertDIE(CallSiteDieParam);
 989     addAddress(*CallSiteDieParam, dwarf::DW_AT_location,
 990                MachineLocation(Register));
 991
 992     DIELoc *Loc = new (DIEValueAllocator) DIELoc;
 993     DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
 994     DwarfExpr.setCallSiteParamValueFlag();
 995
 996     DwarfDebug::emitDebugLocValue(*Asm, nullptr, Param.getValue(), DwarfExpr);
 997
 998     addBlock(*CallSiteDieParam, getDwarf5OrGNUAttr(dwarf::DW_AT_call_value),
 999              DwarfExpr.finalize());
1000
1001     CallSiteDIE.addChild(CallSiteDieParam);
1002   }
1003 }
1004
1005 DIE *DwarfCompileUnit::constructImportedEntityDIE(
1006     const DIImportedEntity *Module) {
1007   DIE *IMDie = DIE::get(DIEValueAllocator, (dwarf::Tag)Module->getTag());
1008   insertDIE(Module, IMDie);
1009   DIE *EntityDie;
1010   auto *Entity = Module->getEntity();
1011   if (auto *NS = dyn_cast<DINamespace>(Entity))
1012     EntityDie = getOrCreateNameSpace(NS);
1013   else if (auto *M = dyn_cast<DIModule>(Entity))
1014     EntityDie = getOrCreateModule(M);
1015   else if (auto *SP = dyn_cast<DISubprogram>(Entity))
1016     EntityDie = getOrCreateSubprogramDIE(SP);
1017   else if (auto *T = dyn_cast<DIType>(Entity))
1018     EntityDie = getOrCreateTypeDIE(T);
1019   else if (auto *GV = dyn_cast<DIGlobalVariable>(Entity))
1020     EntityDie = getOrCreateGlobalVariableDIE(GV, {});
1021   else
1022     EntityDie = getDIE(Entity);
1023   assert(EntityDie);
1024   addSourceLine(*IMDie, Module->getLine(), Module->getFile());
1025   addDIEEntry(*IMDie, dwarf::DW_AT_import, *EntityDie);
1026   StringRef Name = Module->getName();
1027   if (!Name.empty())
1028     addString(*IMDie, dwarf::DW_AT_name, Name);
1029
1030   return IMDie;
1031 }
1032
1033 void DwarfCompileUnit::finishSubprogramDefinition(const DISubprogram *SP) {
1034   DIE *D = getDIE(SP);
1035   if (DIE *AbsSPDIE = getAbstractSPDies().lookup(SP)) {
1036     if (D)
1037       // If this subprogram has an abstract definition, reference that
1038       addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
1039   } else {
1040     assert(D || includeMinimalInlineScopes());
1041     if (D)
1042       // And attach the attributes
1043       applySubprogramAttributesToDefinition(SP, *D);
1044   }
1045 }
1046
1047 void DwarfCompileUnit::finishEntityDefinition(const DbgEntity *Entity) {
1048   DbgEntity *AbsEntity = getExistingAbstractEntity(Entity->getEntity());
1049
1050   auto *Die = Entity->getDIE();
1051   /// Label may be used to generate DW_AT_low_pc, so put it outside
1052   /// if/else block.
1053   const DbgLabel *Label = nullptr;
1054   if (AbsEntity && AbsEntity->getDIE()) {
1055     addDIEEntry(*Die, dwarf::DW_AT_abstract_origin, *AbsEntity->getDIE());
1056     Label = dyn_cast<const DbgLabel>(Entity);
1057   } else {
1058     if (const DbgVariable *Var = dyn_cast<const DbgVariable>(Entity))
1059       applyVariableAttributes(*Var, *Die);
1060     else if ((Label = dyn_cast<const DbgLabel>(Entity)))
1061       applyLabelAttributes(*Label, *Die);
1062     else
1063       llvm_unreachable("DbgEntity must be DbgVariable or DbgLabel.");
1064   }
1065
1066   if (Label)
1067     if (const auto *Sym = Label->getSymbol())
1068       addLabelAddress(*Die, dwarf::DW_AT_low_pc, Sym);
1069 }
1070
1071 DbgEntity *DwarfCompileUnit::getExistingAbstractEntity(const DINode *Node) {
1072   auto &AbstractEntities = getAbstractEntities();
1073   auto I = AbstractEntities.find(Node);
1074   if (I != AbstractEntities.end())
1075     return I->second.get();
1076   return nullptr;
1077 }
1078
1079 void DwarfCompileUnit::createAbstractEntity(const DINode *Node,
1080                                             LexicalScope *Scope) {
1081   assert(Scope && Scope->isAbstractScope());
1082   auto &Entity = getAbstractEntities()[Node];
1083   if (isa<const DILocalVariable>(Node)) {
1084     Entity = std::make_unique<DbgVariable>(
1085                         cast<const DILocalVariable>(Node), nullptr /* IA */);;
1086     DU->addScopeVariable(Scope, cast<DbgVariable>(Entity.get()));
1087   } else if (isa<const DILabel>(Node)) {
1088     Entity = std::make_unique<DbgLabel>(
1089                         cast<const DILabel>(Node), nullptr /* IA */);
1090     DU->addScopeLabel(Scope, cast<DbgLabel>(Entity.get()));
1091   }
1092 }
1093
1094 void DwarfCompileUnit::emitHeader(bool UseOffsets) {
1095   // Don't bother labeling the .dwo unit, as its offset isn't used.
1096   if (!Skeleton && !DD->useSectionsAsReferences()) {
1097     LabelBegin = Asm->createTempSymbol("cu_begin");
1098     Asm->OutStreamer->EmitLabel(LabelBegin);
1099   }
1100
1101   dwarf::UnitType UT = Skeleton ? dwarf::DW_UT_split_compile
1102                                 : DD->useSplitDwarf() ? dwarf::DW_UT_skeleton
1103                                                       : dwarf::DW_UT_compile;
1104   DwarfUnit::emitCommonHeader(UseOffsets, UT);
1105   if (DD->getDwarfVersion() >= 5 && UT != dwarf::DW_UT_compile)
1106     Asm->emitInt64(getDWOId());
1107 }
1108
1109 bool DwarfCompileUnit::hasDwarfPubSections() const {
1110   switch (CUNode->getNameTableKind()) {
1111   case DICompileUnit::DebugNameTableKind::None:
1112     return false;
1113     // Opting in to GNU Pubnames/types overrides the default to ensure these are
1114     // generated for things like Gold's gdb_index generation.
1115   case DICompileUnit::DebugNameTableKind::GNU:
1116     return true;
1117   case DICompileUnit::DebugNameTableKind::Default:
1118     return DD->tuneForGDB() && !includeMinimalInlineScopes() &&
1119            !CUNode->isDebugDirectivesOnly() &&
1120            DD->getAccelTableKind() != AccelTableKind::Apple &&
1121            DD->getDwarfVersion() < 5;
1122   }
1123   llvm_unreachable("Unhandled DICompileUnit::DebugNameTableKind enum");
1124 }
1125
1126 /// addGlobalName - Add a new global name to the compile unit.
1127 void DwarfCompileUnit::addGlobalName(StringRef Name, const DIE &Die,
1128                                      const DIScope *Context) {
1129   if (!hasDwarfPubSections())
1130     return;
1131   std::string FullName = getParentContextString(Context) + Name.str();
1132   GlobalNames[FullName] = &Die;
1133 }
1134
1135 void DwarfCompileUnit::addGlobalNameForTypeUnit(StringRef Name,
1136                                                 const DIScope *Context) {
1137   if (!hasDwarfPubSections())
1138     return;
1139   std::string FullName = getParentContextString(Context) + Name.str();
1140   // Insert, allowing the entry to remain as-is if it's already present
1141   // This way the CU-level type DIE is preferred over the "can't describe this
1142   // type as a unit offset because it's not really in the CU at all, it's only
1143   // in a type unit"
1144   GlobalNames.insert(std::make_pair(std::move(FullName), &getUnitDie()));
1145 }
1146
1147 /// Add a new global type to the unit.
1148 void DwarfCompileUnit::addGlobalType(const DIType *Ty, const DIE &Die,
1149                                      const DIScope *Context) {
1150   if (!hasDwarfPubSections())
1151     return;
1152   std::string FullName = getParentContextString(Context) + Ty->getName().str();
1153   GlobalTypes[FullName] = &Die;
1154 }
1155
1156 void DwarfCompileUnit::addGlobalTypeUnitType(const DIType *Ty,
1157                                              const DIScope *Context) {
1158   if (!hasDwarfPubSections())
1159     return;
1160   std::string FullName = getParentContextString(Context) + Ty->getName().str();
1161   // Insert, allowing the entry to remain as-is if it's already present
1162   // This way the CU-level type DIE is preferred over the "can't describe this
1163   // type as a unit offset because it's not really in the CU at all, it's only
1164   // in a type unit"
1165   GlobalTypes.insert(std::make_pair(std::move(FullName), &getUnitDie()));
1166 }
1167
1168 void DwarfCompileUnit::addVariableAddress(const DbgVariable &DV, DIE &Die,
1169                                           MachineLocation Location) {
1170   if (DV.hasComplexAddress())
1171     addComplexAddress(DV, Die, dwarf::DW_AT_location, Location);
1172   else
1173     addAddress(Die, dwarf::DW_AT_location, Location);
1174 }
1175
1176 /// Add an address attribute to a die based on the location provided.
1177 void DwarfCompileUnit::addAddress(DIE &Die, dwarf::Attribute Attribute,
1178                                   const MachineLocation &Location) {
1179   DIELoc *Loc = new (DIEValueAllocator) DIELoc;
1180   DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
1181   if (Location.isIndirect())
1182     DwarfExpr.setMemoryLocationKind();
1183
1184   DIExpressionCursor Cursor({});
1185   const TargetRegisterInfo &TRI = *Asm->MF->getSubtarget().getRegisterInfo();
1186   if (!DwarfExpr.addMachineRegExpression(TRI, Cursor, Location.getReg()))
1187     return;
1188   DwarfExpr.addExpression(std::move(Cursor));
1189
1190   // Now attach the location information to the DIE.
1191   addBlock(Die, Attribute, DwarfExpr.finalize());
1192 }
1193
1194 /// Start with the address based on the location provided, and generate the
1195 /// DWARF information necessary to find the actual variable given the extra
1196 /// address information encoded in the DbgVariable, starting from the starting
1197 /// location.  Add the DWARF information to the die.
1198 void DwarfCompileUnit::addComplexAddress(const DbgVariable &DV, DIE &Die,
1199                                          dwarf::Attribute Attribute,
1200                                          const MachineLocation &Location) {
1201   DIELoc *Loc = new (DIEValueAllocator) DIELoc;
1202   DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
1203   const DIExpression *DIExpr = DV.getSingleExpression();
1204   DwarfExpr.addFragmentOffset(DIExpr);
1205   if (Location.isIndirect())
1206     DwarfExpr.setMemoryLocationKind();
1207
1208   DIExpressionCursor Cursor(DIExpr);
1209
1210   if (DIExpr->isEntryValue()) {
1211     DwarfExpr.setEntryValueFlag();
1212     DwarfExpr.addEntryValueExpression(Cursor);
1213   }
1214
1215   const TargetRegisterInfo &TRI = *Asm->MF->getSubtarget().getRegisterInfo();
1216   if (!DwarfExpr.addMachineRegExpression(TRI, Cursor, Location.getReg()))
1217     return;
1218   DwarfExpr.addExpression(std::move(Cursor));
1219
1220   // Now attach the location information to the DIE.
1221   addBlock(Die, Attribute, DwarfExpr.finalize());
1222 }
1223
1224 /// Add a Dwarf loclistptr attribute data and value.
1225 void DwarfCompileUnit::addLocationList(DIE &Die, dwarf::Attribute Attribute,
1226                                        unsigned Index) {
1227   dwarf::Form Form = DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
1228                                                 : dwarf::DW_FORM_data4;
1229   Die.addValue(DIEValueAllocator, Attribute, Form, DIELocList(Index));
1230 }
1231
1232 void DwarfCompileUnit::applyVariableAttributes(const DbgVariable &Var,
1233                                                DIE &VariableDie) {
1234   StringRef Name = Var.getName();
1235   if (!Name.empty())
1236     addString(VariableDie, dwarf::DW_AT_name, Name);
1237   const auto *DIVar = Var.getVariable();
1238   if (DIVar)
1239     if (uint32_t AlignInBytes = DIVar->getAlignInBytes())
1240       addUInt(VariableDie, dwarf::DW_AT_alignment, dwarf::DW_FORM_udata,
1241               AlignInBytes);
1242
1243   addSourceLine(VariableDie, DIVar);
1244   addType(VariableDie, Var.getType());
1245   if (Var.isArtificial())
1246     addFlag(VariableDie, dwarf::DW_AT_artificial);
1247 }
1248
1249 void DwarfCompileUnit::applyLabelAttributes(const DbgLabel &Label,
1250                                             DIE &LabelDie) {
1251   StringRef Name = Label.getName();
1252   if (!Name.empty())
1253     addString(LabelDie, dwarf::DW_AT_name, Name);
1254   const auto *DILabel = Label.getLabel();
1255   addSourceLine(LabelDie, DILabel);
1256 }
1257
1258 /// Add a Dwarf expression attribute data and value.
1259 void DwarfCompileUnit::addExpr(DIELoc &Die, dwarf::Form Form,
1260                                const MCExpr *Expr) {
1261   Die.addValue(DIEValueAllocator, (dwarf::Attribute)0, Form, DIEExpr(Expr));
1262 }
1263
1264 void DwarfCompileUnit::addAddressExpr(DIE &Die, dwarf::Attribute Attribute,
1265                                       const MCExpr *Expr) {
1266   Die.addValue(DIEValueAllocator, Attribute, dwarf::DW_FORM_addr,
1267                DIEExpr(Expr));
1268 }
1269
1270 void DwarfCompileUnit::applySubprogramAttributesToDefinition(
1271     const DISubprogram *SP, DIE &SPDie) {
1272   auto *SPDecl = SP->getDeclaration();
1273   auto *Context = SPDecl ? SPDecl->getScope() : SP->getScope();
1274   applySubprogramAttributes(SP, SPDie, includeMinimalInlineScopes());
1275   addGlobalName(SP->getName(), SPDie, Context);
1276 }
1277
1278 bool DwarfCompileUnit::isDwoUnit() const {
1279   return DD->useSplitDwarf() && Skeleton;
1280 }
1281
1282 void DwarfCompileUnit::finishNonUnitTypeDIE(DIE& D, const DICompositeType *CTy) {
1283   constructTypeDIE(D, CTy);
1284 }
1285
1286 bool DwarfCompileUnit::includeMinimalInlineScopes() const {
1287   return getCUNode()->getEmissionKind() == DICompileUnit::LineTablesOnly ||
1288          (DD->useSplitDwarf() && !Skeleton);
1289 }
1290
1291 void DwarfCompileUnit::addAddrTableBase() {
1292   const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
1293   MCSymbol *Label = DD->getAddressPool().getLabel();
1294   addSectionLabel(getUnitDie(),
1295                   getDwarfVersion() >= 5 ? dwarf::DW_AT_addr_base
1296                                          : dwarf::DW_AT_GNU_addr_base,
1297                   Label, TLOF.getDwarfAddrSection()->getBeginSymbol());
1298 }
1299
1300 void DwarfCompileUnit::addBaseTypeRef(DIEValueList &Die, int64_t Idx) {
1301   Die.addValue(DIEValueAllocator, (dwarf::Attribute)0, dwarf::DW_FORM_udata,
1302                new (DIEValueAllocator) DIEBaseTypeRef(this, Idx));
1303 }
1304
1305 void DwarfCompileUnit::createBaseTypeDIEs() {
1306   // Insert the base_type DIEs directly after the CU so that their offsets will
1307   // fit in the fixed size ULEB128 used inside the location expressions.
1308   // Maintain order by iterating backwards and inserting to the front of CU
1309   // child list.
1310   for (auto &Btr : reverse(ExprRefedBaseTypes)) {
1311     DIE &Die = getUnitDie().addChildFront(
1312       DIE::get(DIEValueAllocator, dwarf::DW_TAG_base_type));
1313     SmallString<32> Str;
1314     addString(Die, dwarf::DW_AT_name,
1315               Twine(dwarf::AttributeEncodingString(Btr.Encoding) +
1316                     "_" + Twine(Btr.BitSize)).toStringRef(Str));
1317     addUInt(Die, dwarf::DW_AT_encoding, dwarf::DW_FORM_data1, Btr.Encoding);
1318     addUInt(Die, dwarf::DW_AT_byte_size, None, Btr.BitSize / 8);
1319
1320     Btr.Die = &Die;
1321   }
1322 }