1 //===- CVSymbolVisitor.cpp --------------------------------------*- C++ -*-===//
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/DebugInfo/CodeView/CVSymbolVisitor.h"
10 
11 #include "llvm/DebugInfo/CodeView/CodeView.h"
12 #include "llvm/DebugInfo/CodeView/SymbolRecord.h"
13 #include "llvm/DebugInfo/CodeView/SymbolRecordHelpers.h"
14 #include "llvm/DebugInfo/CodeView/SymbolVisitorCallbacks.h"
15 #include "llvm/Support/BinaryStreamArray.h"
16 #include "llvm/Support/ErrorHandling.h"
17 
18 using namespace llvm;
19 using namespace llvm::codeview;
20 
21 CVSymbolVisitor::CVSymbolVisitor(SymbolVisitorCallbacks &Callbacks)
22     : Callbacks(Callbacks) {}
23 
24 template <typename T>
25 static Error visitKnownRecord(CVSymbol &Record,
26                               SymbolVisitorCallbacks &Callbacks) {
27   SymbolRecordKind RK = static_cast<SymbolRecordKind>(Record.kind());
28   T KnownRecord(RK);
29   if (auto EC = Callbacks.visitKnownRecord(Record, KnownRecord))
30     return EC;
31   return Error::success();
32 }
33 
34 static Error finishVisitation(CVSymbol &Record,
35                               SymbolVisitorCallbacks &Callbacks) {
36   switch (Record.kind()) {
37   default:
38     if (auto EC = Callbacks.visitUnknownSymbol(Record))
39       return EC;
40     break;
41 #define SYMBOL_RECORD(EnumName, EnumVal, Name)                                 \
42   case EnumName: {                                                             \
43     if (auto EC = visitKnownRecord<Name>(Record, Callbacks))                   \
44       return EC;                                                               \
45     break;                                                                     \
46   }
47 #define SYMBOL_RECORD_ALIAS(EnumName, EnumVal, Name, AliasName)                \
48   SYMBOL_RECORD(EnumVal, EnumVal, AliasName)
49 #include "llvm/DebugInfo/CodeView/CodeViewSymbols.def"
50   }
51 
52   if (auto EC = Callbacks.visitSymbolEnd(Record))
53     return EC;
54 
55   return Error::success();
56 }
57 
58 Error CVSymbolVisitor::visitSymbolRecord(CVSymbol &Record) {
59   if (auto EC = Callbacks.visitSymbolBegin(Record))
60     return EC;
61   return finishVisitation(Record, Callbacks);
62 }
63 
64 Error CVSymbolVisitor::visitSymbolRecord(CVSymbol &Record, uint32_t Offset) {
65   if (auto EC = Callbacks.visitSymbolBegin(Record, Offset))
66     return EC;
67   return finishVisitation(Record, Callbacks);
68 }
69 
70 Error CVSymbolVisitor::visitSymbolStream(const CVSymbolArray &Symbols) {
71   for (auto I : Symbols) {
72     if (auto EC = visitSymbolRecord(I))
73       return EC;
74   }
75   return Error::success();
76 }
77 
78 Error CVSymbolVisitor::visitSymbolStream(const CVSymbolArray &Symbols,
79                                          uint32_t InitialOffset) {
80   for (auto I : Symbols) {
81     if (auto EC = visitSymbolRecord(I, InitialOffset + Symbols.skew()))
82       return EC;
83     InitialOffset += I.length();
84   }
85   return Error::success();
86 }
87 
88 Error CVSymbolVisitor::visitSymbolStreamFiltered(const CVSymbolArray &Symbols,
89                                                  const FilterOptions &Filter) {
90   if (!Filter.SymbolOffset)
91     return visitSymbolStream(Symbols);
92   uint32_t SymbolOffset = *Filter.SymbolOffset;
93   uint32_t ParentRecurseDepth = Filter.ParentRecursiveDepth.value_or(0);
94   uint32_t ChildrenRecurseDepth = Filter.ChildRecursiveDepth.value_or(0);
95   if (!Symbols.isOffsetValid(SymbolOffset))
96     return createStringError(inconvertibleErrorCode(), "Invalid symbol offset");
97   CVSymbol Sym = *Symbols.at(SymbolOffset);
98   uint32_t SymEndOffset =
99       symbolOpensScope(Sym.kind()) ? getScopeEndOffset(Sym) : 0;
100 
101   std::vector<uint32_t> ParentOffsets;
102   std::vector<uint32_t> ParentEndOffsets;
103   uint32_t ChildrenDepth = 0;
104   for (auto Begin = Symbols.begin(), End = Symbols.end(); Begin != End;
105        ++Begin) {
106     uint32_t BeginOffset = Begin.offset();
107     CVSymbol BeginSym = *Begin;
108     if (BeginOffset < SymbolOffset) {
109       if (symbolOpensScope(Begin->kind())) {
110         uint32_t EndOffset = getScopeEndOffset(BeginSym);
111         if (SymbolOffset < EndOffset) {
112           ParentOffsets.push_back(BeginOffset);
113           ParentEndOffsets.push_back(EndOffset);
114         }
115       }
116     } else if (BeginOffset == SymbolOffset) {
117       // Found symbol at offset. Visit its parent up to ParentRecurseDepth.
118       if (ParentRecurseDepth >= ParentOffsets.size())
119         ParentRecurseDepth = ParentOffsets.size();
120       uint32_t StartIndex = ParentOffsets.size() - ParentRecurseDepth;
121       while (StartIndex < ParentOffsets.size()) {
122         if (!Symbols.isOffsetValid(ParentOffsets[StartIndex]))
123           break;
124         CVSymbol Parent = *Symbols.at(ParentOffsets[StartIndex]);
125         if (auto EC = visitSymbolRecord(Parent, ParentOffsets[StartIndex]))
126           return EC;
127         ++StartIndex;
128       }
129       if (auto EC = visitSymbolRecord(Sym, SymbolOffset))
130         return EC;
131     } else if (BeginOffset <= SymEndOffset) {
132       if (ChildrenRecurseDepth) {
133         // Visit children.
134         if (symbolEndsScope(Begin->kind()))
135           --ChildrenDepth;
136         if (ChildrenDepth < ChildrenRecurseDepth ||
137             BeginOffset == SymEndOffset) {
138           if (auto EC = visitSymbolRecord(BeginSym, BeginOffset))
139             return EC;
140         }
141         if (symbolOpensScope(Begin->kind()))
142           ++ChildrenDepth;
143       }
144     } else {
145       // Visit parents' ends.
146       if (ParentRecurseDepth && BeginOffset == ParentEndOffsets.back()) {
147         if (auto EC = visitSymbolRecord(BeginSym, BeginOffset))
148           return EC;
149         ParentEndOffsets.pop_back();
150         --ParentRecurseDepth;
151       }
152     }
153   }
154   return Error::success();
155 }
156