1 //===- yaml2coff - Convert YAML to a COFF object file ---------------------===//
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 ///
10 /// \file
11 /// \brief The COFF component of yaml2obj.
12 ///
13 //===----------------------------------------------------------------------===//
14
15 #include "yaml2obj.h"
16 #include "llvm/ADT/SmallString.h"
17 #include "llvm/ADT/StringExtras.h"
18 #include "llvm/ADT/StringMap.h"
19 #include "llvm/ADT/StringSwitch.h"
20 #include "llvm/Object/COFFYAML.h"
21 #include "llvm/Support/Endian.h"
22 #include "llvm/Support/MemoryBuffer.h"
23 #include "llvm/Support/SourceMgr.h"
24 #include "llvm/Support/raw_ostream.h"
25 #include <vector>
26
27 using namespace llvm;
28
29 /// This parses a yaml stream that represents a COFF object file.
30 /// See docs/yaml2obj for the yaml scheema.
31 struct COFFParser {
COFFParserCOFFParser32 COFFParser(COFFYAML::Object &Obj) : Obj(Obj) {
33 // A COFF string table always starts with a 4 byte size field. Offsets into
34 // it include this size, so allocate it now.
35 StringTable.append(4, 0);
36 }
37
parseSectionsCOFFParser38 bool parseSections() {
39 for (std::vector<COFFYAML::Section>::iterator i = Obj.Sections.begin(),
40 e = Obj.Sections.end(); i != e; ++i) {
41 COFFYAML::Section &Sec = *i;
42
43 // If the name is less than 8 bytes, store it in place, otherwise
44 // store it in the string table.
45 StringRef Name = Sec.Name;
46
47 if (Name.size() <= COFF::NameSize) {
48 std::copy(Name.begin(), Name.end(), Sec.Header.Name);
49 } else {
50 // Add string to the string table and format the index for output.
51 unsigned Index = getStringIndex(Name);
52 std::string str = utostr(Index);
53 if (str.size() > 7) {
54 errs() << "String table got too large";
55 return false;
56 }
57 Sec.Header.Name[0] = '/';
58 std::copy(str.begin(), str.end(), Sec.Header.Name + 1);
59 }
60
61 Sec.Header.Characteristics |= (Log2_32(Sec.Alignment) + 1) << 20;
62 }
63 return true;
64 }
65
parseSymbolsCOFFParser66 bool parseSymbols() {
67 for (std::vector<COFFYAML::Symbol>::iterator i = Obj.Symbols.begin(),
68 e = Obj.Symbols.end(); i != e; ++i) {
69 COFFYAML::Symbol &Sym = *i;
70
71 // If the name is less than 8 bytes, store it in place, otherwise
72 // store it in the string table.
73 StringRef Name = Sym.Name;
74 if (Name.size() <= COFF::NameSize) {
75 std::copy(Name.begin(), Name.end(), Sym.Header.Name);
76 } else {
77 // Add string to the string table and format the index for output.
78 unsigned Index = getStringIndex(Name);
79 *reinterpret_cast<support::aligned_ulittle32_t*>(
80 Sym.Header.Name + 4) = Index;
81 }
82
83 Sym.Header.Type = Sym.SimpleType;
84 Sym.Header.Type |= Sym.ComplexType << COFF::SCT_COMPLEX_TYPE_SHIFT;
85 }
86 return true;
87 }
88
parseCOFFParser89 bool parse() {
90 if (!parseSections())
91 return false;
92 if (!parseSymbols())
93 return false;
94 return true;
95 }
96
getStringIndexCOFFParser97 unsigned getStringIndex(StringRef Str) {
98 StringMap<unsigned>::iterator i = StringTableMap.find(Str);
99 if (i == StringTableMap.end()) {
100 unsigned Index = StringTable.size();
101 StringTable.append(Str.begin(), Str.end());
102 StringTable.push_back(0);
103 StringTableMap[Str] = Index;
104 return Index;
105 }
106 return i->second;
107 }
108
109 COFFYAML::Object &Obj;
110
111 StringMap<unsigned> StringTableMap;
112 std::string StringTable;
113 };
114
115 // Take a CP and assign addresses and sizes to everything. Returns false if the
116 // layout is not valid to do.
layoutCOFF(COFFParser & CP)117 static bool layoutCOFF(COFFParser &CP) {
118 uint32_t SectionTableStart = 0;
119 uint32_t SectionTableSize = 0;
120
121 // The section table starts immediately after the header, including the
122 // optional header.
123 SectionTableStart = sizeof(COFF::header) + CP.Obj.Header.SizeOfOptionalHeader;
124 SectionTableSize = sizeof(COFF::section) * CP.Obj.Sections.size();
125
126 uint32_t CurrentSectionDataOffset = SectionTableStart + SectionTableSize;
127
128 // Assign each section data address consecutively.
129 for (std::vector<COFFYAML::Section>::iterator i = CP.Obj.Sections.begin(),
130 e = CP.Obj.Sections.end();
131 i != e; ++i) {
132 if (i->SectionData.binary_size() > 0) {
133 i->Header.SizeOfRawData = i->SectionData.binary_size();
134 i->Header.PointerToRawData = CurrentSectionDataOffset;
135 CurrentSectionDataOffset += i->Header.SizeOfRawData;
136 if (!i->Relocations.empty()) {
137 i->Header.PointerToRelocations = CurrentSectionDataOffset;
138 i->Header.NumberOfRelocations = i->Relocations.size();
139 CurrentSectionDataOffset += i->Header.NumberOfRelocations *
140 COFF::RelocationSize;
141 }
142 // TODO: Handle alignment.
143 } else {
144 i->Header.SizeOfRawData = 0;
145 i->Header.PointerToRawData = 0;
146 }
147 }
148
149 uint32_t SymbolTableStart = CurrentSectionDataOffset;
150
151 // Calculate number of symbols.
152 uint32_t NumberOfSymbols = 0;
153 for (std::vector<COFFYAML::Symbol>::iterator i = CP.Obj.Symbols.begin(),
154 e = CP.Obj.Symbols.end();
155 i != e; ++i) {
156 unsigned AuxBytes = i->AuxiliaryData.binary_size();
157 if (AuxBytes % COFF::SymbolSize != 0) {
158 errs() << "AuxiliaryData size not a multiple of symbol size!\n";
159 return false;
160 }
161 i->Header.NumberOfAuxSymbols = AuxBytes / COFF::SymbolSize;
162 NumberOfSymbols += 1 + i->Header.NumberOfAuxSymbols;
163 }
164
165 // Store all the allocated start addresses in the header.
166 CP.Obj.Header.NumberOfSections = CP.Obj.Sections.size();
167 CP.Obj.Header.NumberOfSymbols = NumberOfSymbols;
168 CP.Obj.Header.PointerToSymbolTable = SymbolTableStart;
169
170 *reinterpret_cast<support::ulittle32_t *>(&CP.StringTable[0])
171 = CP.StringTable.size();
172
173 return true;
174 }
175
176 template <typename value_type>
177 struct binary_le_impl {
178 value_type Value;
binary_le_implbinary_le_impl179 binary_le_impl(value_type V) : Value(V) {}
180 };
181
182 template <typename value_type>
operator <<(raw_ostream & OS,const binary_le_impl<value_type> & BLE)183 raw_ostream &operator <<( raw_ostream &OS
184 , const binary_le_impl<value_type> &BLE) {
185 char Buffer[sizeof(BLE.Value)];
186 support::endian::write<value_type, support::little, support::unaligned>(
187 Buffer, BLE.Value);
188 OS.write(Buffer, sizeof(BLE.Value));
189 return OS;
190 }
191
192 template <typename value_type>
binary_le(value_type V)193 binary_le_impl<value_type> binary_le(value_type V) {
194 return binary_le_impl<value_type>(V);
195 }
196
writeCOFF(COFFParser & CP,raw_ostream & OS)197 bool writeCOFF(COFFParser &CP, raw_ostream &OS) {
198 OS << binary_le(CP.Obj.Header.Machine)
199 << binary_le(CP.Obj.Header.NumberOfSections)
200 << binary_le(CP.Obj.Header.TimeDateStamp)
201 << binary_le(CP.Obj.Header.PointerToSymbolTable)
202 << binary_le(CP.Obj.Header.NumberOfSymbols)
203 << binary_le(CP.Obj.Header.SizeOfOptionalHeader)
204 << binary_le(CP.Obj.Header.Characteristics);
205
206 // Output section table.
207 for (std::vector<COFFYAML::Section>::iterator i = CP.Obj.Sections.begin(),
208 e = CP.Obj.Sections.end();
209 i != e; ++i) {
210 OS.write(i->Header.Name, COFF::NameSize);
211 OS << binary_le(i->Header.VirtualSize)
212 << binary_le(i->Header.VirtualAddress)
213 << binary_le(i->Header.SizeOfRawData)
214 << binary_le(i->Header.PointerToRawData)
215 << binary_le(i->Header.PointerToRelocations)
216 << binary_le(i->Header.PointerToLineNumbers)
217 << binary_le(i->Header.NumberOfRelocations)
218 << binary_le(i->Header.NumberOfLineNumbers)
219 << binary_le(i->Header.Characteristics);
220 }
221
222 unsigned CurSymbol = 0;
223 StringMap<unsigned> SymbolTableIndexMap;
224 for (std::vector<COFFYAML::Symbol>::iterator I = CP.Obj.Symbols.begin(),
225 E = CP.Obj.Symbols.end();
226 I != E; ++I) {
227 SymbolTableIndexMap[I->Name] = CurSymbol;
228 CurSymbol += 1 + I->Header.NumberOfAuxSymbols;
229 }
230
231 // Output section data.
232 for (std::vector<COFFYAML::Section>::iterator i = CP.Obj.Sections.begin(),
233 e = CP.Obj.Sections.end();
234 i != e; ++i) {
235 i->SectionData.writeAsBinary(OS);
236 for (unsigned I2 = 0, E2 = i->Relocations.size(); I2 != E2; ++I2) {
237 const COFFYAML::Relocation &R = i->Relocations[I2];
238 uint32_t SymbolTableIndex = SymbolTableIndexMap[R.SymbolName];
239 OS << binary_le(R.VirtualAddress)
240 << binary_le(SymbolTableIndex)
241 << binary_le(R.Type);
242 }
243 }
244
245 // Output symbol table.
246
247 for (std::vector<COFFYAML::Symbol>::const_iterator i = CP.Obj.Symbols.begin(),
248 e = CP.Obj.Symbols.end();
249 i != e; ++i) {
250 OS.write(i->Header.Name, COFF::NameSize);
251 OS << binary_le(i->Header.Value)
252 << binary_le(i->Header.SectionNumber)
253 << binary_le(i->Header.Type)
254 << binary_le(i->Header.StorageClass)
255 << binary_le(i->Header.NumberOfAuxSymbols);
256 i->AuxiliaryData.writeAsBinary(OS);
257 }
258
259 // Output string table.
260 OS.write(&CP.StringTable[0], CP.StringTable.size());
261 return true;
262 }
263
yaml2coff(llvm::raw_ostream & Out,llvm::MemoryBuffer * Buf)264 int yaml2coff(llvm::raw_ostream &Out, llvm::MemoryBuffer *Buf) {
265 yaml::Input YIn(Buf->getBuffer());
266 COFFYAML::Object Doc;
267 YIn >> Doc;
268 if (YIn.error()) {
269 errs() << "yaml2obj: Failed to parse YAML file!\n";
270 return 1;
271 }
272
273 COFFParser CP(Doc);
274 if (!CP.parse()) {
275 errs() << "yaml2obj: Failed to parse YAML file!\n";
276 return 1;
277 }
278
279 if (!layoutCOFF(CP)) {
280 errs() << "yaml2obj: Failed to layout COFF file!\n";
281 return 1;
282 }
283 if (!writeCOFF(CP, Out)) {
284 errs() << "yaml2obj: Failed to write COFF file!\n";
285 return 1;
286 }
287 return 0;
288 }
289