1 //===- DWARFLinkerCompileUnit.cpp -----------------------------------------===//
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 "llvm/DWARFLinker/DWARFLinkerCompileUnit.h"
10 #include "llvm/DWARFLinker/DWARFLinkerDeclContext.h"
11
12 namespace llvm {
13
14 /// Check if the DIE at \p Idx is in the scope of a function.
inFunctionScope(CompileUnit & U,unsigned Idx)15 static bool inFunctionScope(CompileUnit &U, unsigned Idx) {
16 while (Idx) {
17 if (U.getOrigUnit().getDIEAtIndex(Idx).getTag() == dwarf::DW_TAG_subprogram)
18 return true;
19 Idx = U.getInfo(Idx).ParentIdx;
20 }
21 return false;
22 }
23
getLanguage()24 uint16_t CompileUnit::getLanguage() {
25 if (!Language) {
26 DWARFDie CU = getOrigUnit().getUnitDIE();
27 Language = dwarf::toUnsigned(CU.find(dwarf::DW_AT_language), 0);
28 }
29 return Language;
30 }
31
markEverythingAsKept()32 void CompileUnit::markEverythingAsKept() {
33 unsigned Idx = 0;
34
35 setHasInterestingContent();
36
37 for (auto &I : Info) {
38 // Mark everything that wasn't explicit marked for pruning.
39 I.Keep = !I.Prune;
40 auto DIE = OrigUnit.getDIEAtIndex(Idx++);
41
42 // Try to guess which DIEs must go to the accelerator tables. We do that
43 // just for variables, because functions will be handled depending on
44 // whether they carry a DW_AT_low_pc attribute or not.
45 if (DIE.getTag() != dwarf::DW_TAG_variable &&
46 DIE.getTag() != dwarf::DW_TAG_constant)
47 continue;
48
49 Optional<DWARFFormValue> Value;
50 if (!(Value = DIE.find(dwarf::DW_AT_location))) {
51 if ((Value = DIE.find(dwarf::DW_AT_const_value)) &&
52 !inFunctionScope(*this, I.ParentIdx))
53 I.InDebugMap = true;
54 continue;
55 }
56 if (auto Block = Value->getAsBlock()) {
57 if (Block->size() > OrigUnit.getAddressByteSize() &&
58 (*Block)[0] == dwarf::DW_OP_addr)
59 I.InDebugMap = true;
60 }
61 }
62 }
63
computeNextUnitOffset()64 uint64_t CompileUnit::computeNextUnitOffset() {
65 NextUnitOffset = StartOffset;
66 if (NewUnit) {
67 NextUnitOffset += 11 /* Header size */;
68 NextUnitOffset += NewUnit->getUnitDie().getSize();
69 }
70 return NextUnitOffset;
71 }
72
73 /// Keep track of a forward cross-cu reference from this unit
74 /// to \p Die that lives in \p RefUnit.
noteForwardReference(DIE * Die,const CompileUnit * RefUnit,DeclContext * Ctxt,PatchLocation Attr)75 void CompileUnit::noteForwardReference(DIE *Die, const CompileUnit *RefUnit,
76 DeclContext *Ctxt, PatchLocation Attr) {
77 ForwardDIEReferences.emplace_back(Die, RefUnit, Ctxt, Attr);
78 }
79
fixupForwardReferences()80 void CompileUnit::fixupForwardReferences() {
81 for (const auto &Ref : ForwardDIEReferences) {
82 DIE *RefDie;
83 const CompileUnit *RefUnit;
84 PatchLocation Attr;
85 DeclContext *Ctxt;
86 std::tie(RefDie, RefUnit, Ctxt, Attr) = Ref;
87 if (Ctxt && Ctxt->getCanonicalDIEOffset())
88 Attr.set(Ctxt->getCanonicalDIEOffset());
89 else
90 Attr.set(RefDie->getOffset() + RefUnit->getStartOffset());
91 }
92 }
93
addLabelLowPc(uint64_t LabelLowPc,int64_t PcOffset)94 void CompileUnit::addLabelLowPc(uint64_t LabelLowPc, int64_t PcOffset) {
95 Labels.insert({LabelLowPc, PcOffset});
96 }
97
addFunctionRange(uint64_t FuncLowPc,uint64_t FuncHighPc,int64_t PcOffset)98 void CompileUnit::addFunctionRange(uint64_t FuncLowPc, uint64_t FuncHighPc,
99 int64_t PcOffset) {
100 // Don't add empty ranges to the interval map. They are a problem because
101 // the interval map expects half open intervals. This is safe because they
102 // are empty anyway.
103 if (FuncHighPc != FuncLowPc)
104 Ranges.insert(FuncLowPc, FuncHighPc, PcOffset);
105 this->LowPc = std::min(LowPc, FuncLowPc + PcOffset);
106 this->HighPc = std::max(HighPc, FuncHighPc + PcOffset);
107 }
108
noteRangeAttribute(const DIE & Die,PatchLocation Attr)109 void CompileUnit::noteRangeAttribute(const DIE &Die, PatchLocation Attr) {
110 if (Die.getTag() != dwarf::DW_TAG_compile_unit)
111 RangeAttributes.push_back(Attr);
112 else
113 UnitRangeAttribute = Attr;
114 }
115
noteLocationAttribute(PatchLocation Attr,int64_t PcOffset)116 void CompileUnit::noteLocationAttribute(PatchLocation Attr, int64_t PcOffset) {
117 LocationAttributes.emplace_back(Attr, PcOffset);
118 }
119
addNamespaceAccelerator(const DIE * Die,DwarfStringPoolEntryRef Name)120 void CompileUnit::addNamespaceAccelerator(const DIE *Die,
121 DwarfStringPoolEntryRef Name) {
122 Namespaces.emplace_back(Name, Die);
123 }
124
addObjCAccelerator(const DIE * Die,DwarfStringPoolEntryRef Name,bool SkipPubSection)125 void CompileUnit::addObjCAccelerator(const DIE *Die,
126 DwarfStringPoolEntryRef Name,
127 bool SkipPubSection) {
128 ObjC.emplace_back(Name, Die, SkipPubSection);
129 }
130
addNameAccelerator(const DIE * Die,DwarfStringPoolEntryRef Name,bool SkipPubSection)131 void CompileUnit::addNameAccelerator(const DIE *Die,
132 DwarfStringPoolEntryRef Name,
133 bool SkipPubSection) {
134 Pubnames.emplace_back(Name, Die, SkipPubSection);
135 }
136
addTypeAccelerator(const DIE * Die,DwarfStringPoolEntryRef Name,bool ObjcClassImplementation,uint32_t QualifiedNameHash)137 void CompileUnit::addTypeAccelerator(const DIE *Die,
138 DwarfStringPoolEntryRef Name,
139 bool ObjcClassImplementation,
140 uint32_t QualifiedNameHash) {
141 Pubtypes.emplace_back(Name, Die, QualifiedNameHash, ObjcClassImplementation);
142 }
143
144 } // namespace llvm
145