1 //===--- LayoutOverrideSource.cpp --Override Record Layouts ---------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 #include "clang/Frontend/LayoutOverrideSource.h" 10 #include "clang/AST/Decl.h" 11 #include "clang/Basic/CharInfo.h" 12 #include "llvm/Support/raw_ostream.h" 13 #include <fstream> 14 #include <string> 15 16 using namespace clang; 17 18 /// \brief Parse a simple identifier. 19 static std::string parseName(StringRef S) { 20 if (S.empty() || !isIdentifierHead(S[0])) 21 return ""; 22 23 unsigned Offset = 1; 24 while (Offset < S.size() && isIdentifierBody(S[Offset])) 25 ++Offset; 26 27 return S.substr(0, Offset).str(); 28 } 29 30 LayoutOverrideSource::LayoutOverrideSource(StringRef Filename) { 31 std::ifstream Input(Filename.str().c_str()); 32 if (!Input.is_open()) 33 return; 34 35 // Parse the output of -fdump-record-layouts. 36 std::string CurrentType; 37 Layout CurrentLayout; 38 bool ExpectingType = false; 39 40 while (Input.good()) { 41 std::string Line; 42 getline(Input, Line); 43 44 StringRef LineStr(Line); 45 46 // Determine whether the following line will start a 47 if (LineStr.find("*** Dumping AST Record Layout") != StringRef::npos) { 48 // Flush the last type/layout, if there is one. 49 if (!CurrentType.empty()) 50 Layouts[CurrentType] = CurrentLayout; 51 CurrentLayout = Layout(); 52 53 ExpectingType = true; 54 continue; 55 } 56 57 // If we're expecting a type, grab it. 58 if (ExpectingType) { 59 ExpectingType = false; 60 61 StringRef::size_type Pos; 62 if ((Pos = LineStr.find("struct ")) != StringRef::npos) 63 LineStr = LineStr.substr(Pos + strlen("struct ")); 64 else if ((Pos = LineStr.find("class ")) != StringRef::npos) 65 LineStr = LineStr.substr(Pos + strlen("class ")); 66 else if ((Pos = LineStr.find("union ")) != StringRef::npos) 67 LineStr = LineStr.substr(Pos + strlen("union ")); 68 else 69 continue; 70 71 // Find the name of the type. 72 CurrentType = parseName(LineStr); 73 CurrentLayout = Layout(); 74 continue; 75 } 76 77 // Check for the size of the type. 78 StringRef::size_type Pos = LineStr.find(" Size:"); 79 if (Pos != StringRef::npos) { 80 // Skip past the " Size:" prefix. 81 LineStr = LineStr.substr(Pos + strlen(" Size:")); 82 83 unsigned long long Size = 0; 84 (void)LineStr.getAsInteger(10, Size); 85 CurrentLayout.Size = Size; 86 continue; 87 } 88 89 // Check for the alignment of the type. 90 Pos = LineStr.find("Alignment:"); 91 if (Pos != StringRef::npos) { 92 // Skip past the "Alignment:" prefix. 93 LineStr = LineStr.substr(Pos + strlen("Alignment:")); 94 95 unsigned long long Alignment = 0; 96 (void)LineStr.getAsInteger(10, Alignment); 97 CurrentLayout.Align = Alignment; 98 continue; 99 } 100 101 // Check for the size/alignment of the type. 102 Pos = LineStr.find("sizeof="); 103 if (Pos != StringRef::npos) { 104 /* Skip past the sizeof= prefix. */ 105 LineStr = LineStr.substr(Pos + strlen("sizeof=")); 106 107 // Parse size. 108 unsigned long long Size = 0; 109 (void)LineStr.getAsInteger(10, Size); 110 CurrentLayout.Size = Size; 111 112 Pos = LineStr.find("align="); 113 if (Pos != StringRef::npos) { 114 /* Skip past the align= prefix. */ 115 LineStr = LineStr.substr(Pos + strlen("align=")); 116 117 // Parse alignment. 118 unsigned long long Alignment = 0; 119 (void)LineStr.getAsInteger(10, Alignment); 120 CurrentLayout.Align = Alignment; 121 } 122 123 continue; 124 } 125 126 // Check for the field offsets of the type. 127 Pos = LineStr.find("FieldOffsets: ["); 128 if (Pos == StringRef::npos) 129 continue; 130 131 LineStr = LineStr.substr(Pos + strlen("FieldOffsets: [")); 132 while (!LineStr.empty() && isDigit(LineStr[0])) { 133 // Parse this offset. 134 unsigned Idx = 1; 135 while (Idx < LineStr.size() && isDigit(LineStr[Idx])) 136 ++Idx; 137 138 unsigned long long Offset = 0; 139 (void)LineStr.substr(0, Idx).getAsInteger(10, Offset); 140 141 CurrentLayout.FieldOffsets.push_back(Offset); 142 143 // Skip over this offset, the following comma, and any spaces. 144 LineStr = LineStr.substr(Idx + 1); 145 while (!LineStr.empty() && isWhitespace(LineStr[0])) 146 LineStr = LineStr.substr(1); 147 } 148 } 149 150 // Flush the last type/layout, if there is one. 151 if (!CurrentType.empty()) 152 Layouts[CurrentType] = CurrentLayout; 153 } 154 155 bool 156 LayoutOverrideSource::layoutRecordType(const RecordDecl *Record, 157 uint64_t &Size, uint64_t &Alignment, 158 llvm::DenseMap<const FieldDecl *, uint64_t> &FieldOffsets, 159 llvm::DenseMap<const CXXRecordDecl *, CharUnits> &BaseOffsets, 160 llvm::DenseMap<const CXXRecordDecl *, CharUnits> &VirtualBaseOffsets) 161 { 162 // We can't override unnamed declarations. 163 if (!Record->getIdentifier()) 164 return false; 165 166 // Check whether we have a layout for this record. 167 llvm::StringMap<Layout>::iterator Known = Layouts.find(Record->getName()); 168 if (Known == Layouts.end()) 169 return false; 170 171 // Provide field layouts. 172 unsigned NumFields = 0; 173 for (RecordDecl::field_iterator F = Record->field_begin(), 174 FEnd = Record->field_end(); 175 F != FEnd; ++F, ++NumFields) { 176 if (NumFields >= Known->second.FieldOffsets.size()) 177 continue; 178 179 FieldOffsets[*F] = Known->second.FieldOffsets[NumFields]; 180 } 181 182 // Wrong number of fields. 183 if (NumFields != Known->second.FieldOffsets.size()) 184 return false; 185 186 Size = Known->second.Size; 187 Alignment = Known->second.Align; 188 return true; 189 } 190 191 LLVM_DUMP_METHOD void LayoutOverrideSource::dump() { 192 raw_ostream &OS = llvm::errs(); 193 for (llvm::StringMap<Layout>::iterator L = Layouts.begin(), 194 LEnd = Layouts.end(); 195 L != LEnd; ++L) { 196 OS << "Type: blah " << L->first() << '\n'; 197 OS << " Size:" << L->second.Size << '\n'; 198 OS << " Alignment:" << L->second.Align << '\n'; 199 OS << " FieldOffsets: ["; 200 for (unsigned I = 0, N = L->second.FieldOffsets.size(); I != N; ++I) { 201 if (I) 202 OS << ", "; 203 OS << L->second.FieldOffsets[I]; 204 } 205 OS << "]\n"; 206 } 207 } 208 209