tools/dsymutil/CompileUnit.cpp

   1 //===- tools/dsymutil/CompileUnit.h - Dwarf compile unit ------------------===//
   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 #include "CompileUnit.h"
  10 #include "DeclContext.h"
  11
  12 namespace llvm {
  13 namespace dsymutil {
  14
  15 /// Check if the DIE at \p Idx is in the scope of a function.
  16 static bool inFunctionScope(CompileUnit &U, unsigned Idx) {
  17   while (Idx) {
  18     if (U.getOrigUnit().getDIEAtIndex(Idx).getTag() == dwarf::DW_TAG_subprogram)
  19       return true;
  20     Idx = U.getInfo(Idx).ParentIdx;
  21   }
  22   return false;
  23 }
  24
  25 void CompileUnit::markEverythingAsKept() {
  26   unsigned Idx = 0;
  27
  28   setHasInterestingContent();
  29
  30   for (auto &I : Info) {
  31     // Mark everything that wasn't explicit marked for pruning.
  32     I.Keep = !I.Prune;
  33     auto DIE = OrigUnit.getDIEAtIndex(Idx++);
  34
  35     // Try to guess which DIEs must go to the accelerator tables. We do that
  36     // just for variables, because functions will be handled depending on
  37     // whether they carry a DW_AT_low_pc attribute or not.
  38     if (DIE.getTag() != dwarf::DW_TAG_variable &&
  39         DIE.getTag() != dwarf::DW_TAG_constant)
  40       continue;
  41
  42     Optional<DWARFFormValue> Value;
  43     if (!(Value = DIE.find(dwarf::DW_AT_location))) {
  44       if ((Value = DIE.find(dwarf::DW_AT_const_value)) &&
  45           !inFunctionScope(*this, I.ParentIdx))
  46         I.InDebugMap = true;
  47       continue;
  48     }
  49     if (auto Block = Value->getAsBlock()) {
  50       if (Block->size() > OrigUnit.getAddressByteSize() &&
  51           (*Block)[0] == dwarf::DW_OP_addr)
  52         I.InDebugMap = true;
  53     }
  54   }
  55 }
  56
  57 uint64_t CompileUnit::computeNextUnitOffset() {
  58   NextUnitOffset = StartOffset + 11 /* Header size */;
  59   // The root DIE might be null, meaning that the Unit had nothing to
  60   // contribute to the linked output. In that case, we will emit the
  61   // unit header without any actual DIE.
  62   if (NewUnit)
  63     NextUnitOffset += NewUnit->getUnitDie().getSize();
  64   return NextUnitOffset;
  65 }
  66
  67 /// Keep track of a forward cross-cu reference from this unit
  68 /// to \p Die that lives in \p RefUnit.
  69 void CompileUnit::noteForwardReference(DIE *Die, const CompileUnit *RefUnit,
  70                                        DeclContext *Ctxt, PatchLocation Attr) {
  71   ForwardDIEReferences.emplace_back(Die, RefUnit, Ctxt, Attr);
  72 }
  73
  74 void CompileUnit::fixupForwardReferences() {
  75   for (const auto &Ref : ForwardDIEReferences) {
  76     DIE *RefDie;
  77     const CompileUnit *RefUnit;
  78     PatchLocation Attr;
  79     DeclContext *Ctxt;
  80     std::tie(RefDie, RefUnit, Ctxt, Attr) = Ref;
  81     if (Ctxt && Ctxt->getCanonicalDIEOffset())
  82       Attr.set(Ctxt->getCanonicalDIEOffset());
  83     else
  84       Attr.set(RefDie->getOffset() + RefUnit->getStartOffset());
  85   }
  86 }
  87
  88 void CompileUnit::addLabelLowPc(uint64_t LabelLowPc, int64_t PcOffset) {
  89   Labels.insert({LabelLowPc, PcOffset});
  90 }
  91
  92 void CompileUnit::addFunctionRange(uint64_t FuncLowPc, uint64_t FuncHighPc,
  93                                    int64_t PcOffset) {
  94   //  Don't add empty ranges to the interval map.  They are a problem because
  95   //  the interval map expects half open intervals. This is safe because they
  96   //  are empty anyway.
  97   if (FuncHighPc != FuncLowPc)
  98     Ranges.insert(FuncLowPc, FuncHighPc, PcOffset);
  99   this->LowPc = std::min(LowPc, FuncLowPc + PcOffset);
 100   this->HighPc = std::max(HighPc, FuncHighPc + PcOffset);
 101 }
 102
 103 void CompileUnit::noteRangeAttribute(const DIE &Die, PatchLocation Attr) {
 104   if (Die.getTag() != dwarf::DW_TAG_compile_unit)
 105     RangeAttributes.push_back(Attr);
 106   else
 107     UnitRangeAttribute = Attr;
 108 }
 109
 110 void CompileUnit::noteLocationAttribute(PatchLocation Attr, int64_t PcOffset) {
 111   LocationAttributes.emplace_back(Attr, PcOffset);
 112 }
 113
 114 void CompileUnit::addNamespaceAccelerator(const DIE *Die,
 115                                           DwarfStringPoolEntryRef Name) {
 116   Namespaces.emplace_back(Name, Die);
 117 }
 118
 119 void CompileUnit::addObjCAccelerator(const DIE *Die,
 120                                      DwarfStringPoolEntryRef Name,
 121                                      bool SkipPubSection) {
 122   ObjC.emplace_back(Name, Die, SkipPubSection);
 123 }
 124
 125 void CompileUnit::addNameAccelerator(const DIE *Die,
 126                                      DwarfStringPoolEntryRef Name,
 127                                      bool SkipPubSection) {
 128   Pubnames.emplace_back(Name, Die, SkipPubSection);
 129 }
 130
 131 void CompileUnit::addTypeAccelerator(const DIE *Die,
 132                                      DwarfStringPoolEntryRef Name,
 133                                      bool ObjcClassImplementation,
 134                                      uint32_t QualifiedNameHash) {
 135   Pubtypes.emplace_back(Name, Die, QualifiedNameHash, ObjcClassImplementation);
 136 }
 137
 138 } // namespace dsymutil
 139 } // namespace llvm