1 //===- COFFObjectFile.cpp - COFF object file implementation -----*- C++ -*-===//
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 // This file declares the COFFObjectFile class.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "llvm/Object/COFF.h"
15 #include "llvm/ADT/StringSwitch.h"
16 #include "llvm/ADT/Triple.h"
17
18 using namespace llvm;
19 using namespace object;
20
21 namespace {
22 using support::ulittle8_t;
23 using support::ulittle16_t;
24 using support::ulittle32_t;
25 using support::little16_t;
26 }
27
28 namespace {
29 // Returns false if size is greater than the buffer size. And sets ec.
checkSize(const MemoryBuffer * m,error_code & ec,uint64_t size)30 bool checkSize(const MemoryBuffer *m, error_code &ec, uint64_t size) {
31 if (m->getBufferSize() < size) {
32 ec = object_error::unexpected_eof;
33 return false;
34 }
35 return true;
36 }
37
38 // Returns false if any bytes in [addr, addr + size) fall outsize of m.
checkAddr(const MemoryBuffer * m,error_code & ec,uintptr_t addr,uint64_t size)39 bool checkAddr(const MemoryBuffer *m,
40 error_code &ec,
41 uintptr_t addr,
42 uint64_t size) {
43 if (addr + size < addr ||
44 addr + size < size ||
45 addr + size > uintptr_t(m->getBufferEnd())) {
46 ec = object_error::unexpected_eof;
47 return false;
48 }
49 return true;
50 }
51 }
52
toSymb(DataRefImpl Symb) const53 const coff_symbol *COFFObjectFile::toSymb(DataRefImpl Symb) const {
54 const coff_symbol *addr = reinterpret_cast<const coff_symbol*>(Symb.p);
55
56 # ifndef NDEBUG
57 // Verify that the symbol points to a valid entry in the symbol table.
58 uintptr_t offset = uintptr_t(addr) - uintptr_t(base());
59 if (offset < Header->PointerToSymbolTable
60 || offset >= Header->PointerToSymbolTable
61 + (Header->NumberOfSymbols * sizeof(coff_symbol)))
62 report_fatal_error("Symbol was outside of symbol table.");
63
64 assert((offset - Header->PointerToSymbolTable) % sizeof(coff_symbol)
65 == 0 && "Symbol did not point to the beginning of a symbol");
66 # endif
67
68 return addr;
69 }
70
toSec(DataRefImpl Sec) const71 const coff_section *COFFObjectFile::toSec(DataRefImpl Sec) const {
72 const coff_section *addr = reinterpret_cast<const coff_section*>(Sec.p);
73
74 # ifndef NDEBUG
75 // Verify that the section points to a valid entry in the section table.
76 if (addr < SectionTable
77 || addr >= (SectionTable + Header->NumberOfSections))
78 report_fatal_error("Section was outside of section table.");
79
80 uintptr_t offset = uintptr_t(addr) - uintptr_t(SectionTable);
81 assert(offset % sizeof(coff_section) == 0 &&
82 "Section did not point to the beginning of a section");
83 # endif
84
85 return addr;
86 }
87
getSymbolNext(DataRefImpl Symb,SymbolRef & Result) const88 error_code COFFObjectFile::getSymbolNext(DataRefImpl Symb,
89 SymbolRef &Result) const {
90 const coff_symbol *symb = toSymb(Symb);
91 symb += 1 + symb->NumberOfAuxSymbols;
92 Symb.p = reinterpret_cast<uintptr_t>(symb);
93 Result = SymbolRef(Symb, this);
94 return object_error::success;
95 }
96
getSymbolName(DataRefImpl Symb,StringRef & Result) const97 error_code COFFObjectFile::getSymbolName(DataRefImpl Symb,
98 StringRef &Result) const {
99 const coff_symbol *symb = toSymb(Symb);
100 // Check for string table entry. First 4 bytes are 0.
101 if (symb->Name.Offset.Zeroes == 0) {
102 uint32_t Offset = symb->Name.Offset.Offset;
103 if (error_code ec = getString(Offset, Result))
104 return ec;
105 return object_error::success;
106 }
107
108 if (symb->Name.ShortName[7] == 0)
109 // Null terminated, let ::strlen figure out the length.
110 Result = StringRef(symb->Name.ShortName);
111 else
112 // Not null terminated, use all 8 bytes.
113 Result = StringRef(symb->Name.ShortName, 8);
114 return object_error::success;
115 }
116
getSymbolAddress(DataRefImpl Symb,uint64_t & Result) const117 error_code COFFObjectFile::getSymbolAddress(DataRefImpl Symb,
118 uint64_t &Result) const {
119 const coff_symbol *symb = toSymb(Symb);
120 const coff_section *Section = NULL;
121 if (error_code ec = getSection(symb->SectionNumber, Section))
122 return ec;
123 char Type;
124 if (error_code ec = getSymbolNMTypeChar(Symb, Type))
125 return ec;
126 if (Type == 'U' || Type == 'w')
127 Result = UnknownAddressOrSize;
128 else if (Section)
129 Result = Section->VirtualAddress + symb->Value;
130 else
131 Result = symb->Value;
132 return object_error::success;
133 }
134
getSymbolSize(DataRefImpl Symb,uint64_t & Result) const135 error_code COFFObjectFile::getSymbolSize(DataRefImpl Symb,
136 uint64_t &Result) const {
137 // FIXME: Return the correct size. This requires looking at all the symbols
138 // in the same section as this symbol, and looking for either the next
139 // symbol, or the end of the section.
140 const coff_symbol *symb = toSymb(Symb);
141 const coff_section *Section = NULL;
142 if (error_code ec = getSection(symb->SectionNumber, Section))
143 return ec;
144 char Type;
145 if (error_code ec = getSymbolNMTypeChar(Symb, Type))
146 return ec;
147 if (Type == 'U' || Type == 'w')
148 Result = UnknownAddressOrSize;
149 else if (Section)
150 Result = Section->SizeOfRawData - symb->Value;
151 else
152 Result = 0;
153 return object_error::success;
154 }
155
getSymbolNMTypeChar(DataRefImpl Symb,char & Result) const156 error_code COFFObjectFile::getSymbolNMTypeChar(DataRefImpl Symb,
157 char &Result) const {
158 const coff_symbol *symb = toSymb(Symb);
159 StringRef name;
160 if (error_code ec = getSymbolName(Symb, name))
161 return ec;
162 char ret = StringSwitch<char>(name)
163 .StartsWith(".debug", 'N')
164 .StartsWith(".sxdata", 'N')
165 .Default('?');
166
167 if (ret != '?') {
168 Result = ret;
169 return object_error::success;
170 }
171
172 uint32_t Characteristics = 0;
173 if (symb->SectionNumber > 0) {
174 const coff_section *Section = NULL;
175 if (error_code ec = getSection(symb->SectionNumber, Section))
176 return ec;
177 Characteristics = Section->Characteristics;
178 }
179
180 switch (symb->SectionNumber) {
181 case COFF::IMAGE_SYM_UNDEFINED:
182 // Check storage classes.
183 if (symb->StorageClass == COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL) {
184 Result = 'w';
185 return object_error::success; // Don't do ::toupper.
186 } else
187 ret = 'u';
188 break;
189 case COFF::IMAGE_SYM_ABSOLUTE:
190 ret = 'a';
191 break;
192 case COFF::IMAGE_SYM_DEBUG:
193 ret = 'n';
194 break;
195 default:
196 // Check section type.
197 if (Characteristics & COFF::IMAGE_SCN_CNT_CODE)
198 ret = 't';
199 else if ( Characteristics & COFF::IMAGE_SCN_MEM_READ
200 && ~Characteristics & COFF::IMAGE_SCN_MEM_WRITE) // Read only.
201 ret = 'r';
202 else if (Characteristics & COFF::IMAGE_SCN_CNT_INITIALIZED_DATA)
203 ret = 'd';
204 else if (Characteristics & COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA)
205 ret = 'b';
206 else if (Characteristics & COFF::IMAGE_SCN_LNK_INFO)
207 ret = 'i';
208
209 // Check for section symbol.
210 else if ( symb->StorageClass == COFF::IMAGE_SYM_CLASS_STATIC
211 && symb->Value == 0)
212 ret = 's';
213 }
214
215 if (symb->StorageClass == COFF::IMAGE_SYM_CLASS_EXTERNAL)
216 ret = ::toupper(ret);
217
218 Result = ret;
219 return object_error::success;
220 }
221
isSymbolInternal(DataRefImpl Symb,bool & Result) const222 error_code COFFObjectFile::isSymbolInternal(DataRefImpl Symb,
223 bool &Result) const {
224 Result = false;
225 return object_error::success;
226 }
227
getSectionNext(DataRefImpl Sec,SectionRef & Result) const228 error_code COFFObjectFile::getSectionNext(DataRefImpl Sec,
229 SectionRef &Result) const {
230 const coff_section *sec = toSec(Sec);
231 sec += 1;
232 Sec.p = reinterpret_cast<uintptr_t>(sec);
233 Result = SectionRef(Sec, this);
234 return object_error::success;
235 }
236
getSectionName(DataRefImpl Sec,StringRef & Result) const237 error_code COFFObjectFile::getSectionName(DataRefImpl Sec,
238 StringRef &Result) const {
239 const coff_section *sec = toSec(Sec);
240 StringRef name;
241 if (sec->Name[7] == 0)
242 // Null terminated, let ::strlen figure out the length.
243 name = sec->Name;
244 else
245 // Not null terminated, use all 8 bytes.
246 name = StringRef(sec->Name, 8);
247
248 // Check for string table entry. First byte is '/'.
249 if (name[0] == '/') {
250 uint32_t Offset;
251 name.substr(1).getAsInteger(10, Offset);
252 if (error_code ec = getString(Offset, name))
253 return ec;
254 }
255
256 Result = name;
257 return object_error::success;
258 }
259
getSectionAddress(DataRefImpl Sec,uint64_t & Result) const260 error_code COFFObjectFile::getSectionAddress(DataRefImpl Sec,
261 uint64_t &Result) const {
262 const coff_section *sec = toSec(Sec);
263 Result = sec->VirtualAddress;
264 return object_error::success;
265 }
266
getSectionSize(DataRefImpl Sec,uint64_t & Result) const267 error_code COFFObjectFile::getSectionSize(DataRefImpl Sec,
268 uint64_t &Result) const {
269 const coff_section *sec = toSec(Sec);
270 Result = sec->SizeOfRawData;
271 return object_error::success;
272 }
273
getSectionContents(DataRefImpl Sec,StringRef & Result) const274 error_code COFFObjectFile::getSectionContents(DataRefImpl Sec,
275 StringRef &Result) const {
276 const coff_section *sec = toSec(Sec);
277 // The only thing that we need to verify is that the contents is contained
278 // within the file bounds. We don't need to make sure it doesn't cover other
279 // data, as there's nothing that says that is not allowed.
280 uintptr_t con_start = uintptr_t(base()) + sec->PointerToRawData;
281 uintptr_t con_end = con_start + sec->SizeOfRawData;
282 if (con_end >= uintptr_t(Data->getBufferEnd()))
283 return object_error::parse_failed;
284 Result = StringRef(reinterpret_cast<const char*>(con_start),
285 sec->SizeOfRawData);
286 return object_error::success;
287 }
288
isSectionText(DataRefImpl Sec,bool & Result) const289 error_code COFFObjectFile::isSectionText(DataRefImpl Sec,
290 bool &Result) const {
291 const coff_section *sec = toSec(Sec);
292 Result = sec->Characteristics & COFF::IMAGE_SCN_CNT_CODE;
293 return object_error::success;
294 }
295
sectionContainsSymbol(DataRefImpl Sec,DataRefImpl Symb,bool & Result) const296 error_code COFFObjectFile::sectionContainsSymbol(DataRefImpl Sec,
297 DataRefImpl Symb,
298 bool &Result) const {
299 // FIXME: Unimplemented.
300 Result = false;
301 return object_error::success;
302 }
303
COFFObjectFile(MemoryBuffer * Object,error_code & ec)304 COFFObjectFile::COFFObjectFile(MemoryBuffer *Object, error_code &ec)
305 : ObjectFile(Binary::isCOFF, Object, ec) {
306 // Check that we at least have enough room for a header.
307 if (!checkSize(Data, ec, sizeof(coff_file_header))) return;
308
309 // The actual starting location of the COFF header in the file. This can be
310 // non-zero in PE/COFF files.
311 uint64_t HeaderStart = 0;
312
313 // Check if this is a PE/COFF file.
314 if (base()[0] == 0x4d && base()[1] == 0x5a) {
315 // PE/COFF, seek through MS-DOS compatibility stub and 4-byte
316 // PE signature to find 'normal' COFF header.
317 if (!checkSize(Data, ec, 0x3c + 8)) return;
318 HeaderStart += *reinterpret_cast<const ulittle32_t *>(base() + 0x3c);
319 // Check the PE header. ("PE\0\0")
320 if (std::memcmp(base() + HeaderStart, "PE\0\0", 4) != 0) {
321 ec = object_error::parse_failed;
322 return;
323 }
324 HeaderStart += 4; // Skip the PE Header.
325 }
326
327 Header = reinterpret_cast<const coff_file_header *>(base() + HeaderStart);
328 if (!checkAddr(Data, ec, uintptr_t(Header), sizeof(coff_file_header)))
329 return;
330
331 SectionTable =
332 reinterpret_cast<const coff_section *>( base()
333 + HeaderStart
334 + sizeof(coff_file_header)
335 + Header->SizeOfOptionalHeader);
336 if (!checkAddr(Data, ec, uintptr_t(SectionTable),
337 Header->NumberOfSections * sizeof(coff_section)))
338 return;
339
340 SymbolTable =
341 reinterpret_cast<const coff_symbol *>(base()
342 + Header->PointerToSymbolTable);
343 if (!checkAddr(Data, ec, uintptr_t(SymbolTable),
344 Header->NumberOfSymbols * sizeof(coff_symbol)))
345 return;
346
347 // Find string table.
348 StringTable = reinterpret_cast<const char *>(base())
349 + Header->PointerToSymbolTable
350 + Header->NumberOfSymbols * sizeof(coff_symbol);
351 if (!checkAddr(Data, ec, uintptr_t(StringTable), sizeof(ulittle32_t)))
352 return;
353
354 StringTableSize = *reinterpret_cast<const ulittle32_t *>(StringTable);
355 if (!checkAddr(Data, ec, uintptr_t(StringTable), StringTableSize))
356 return;
357 // Check that the string table is null terminated if has any in it.
358 if (StringTableSize < 4
359 || (StringTableSize > 4 && StringTable[StringTableSize - 1] != 0)) {
360 ec = object_error::parse_failed;
361 return;
362 }
363
364 ec = object_error::success;
365 }
366
begin_symbols() const367 ObjectFile::symbol_iterator COFFObjectFile::begin_symbols() const {
368 DataRefImpl ret;
369 std::memset(&ret, 0, sizeof(DataRefImpl));
370 ret.p = reinterpret_cast<intptr_t>(SymbolTable);
371 return symbol_iterator(SymbolRef(ret, this));
372 }
373
end_symbols() const374 ObjectFile::symbol_iterator COFFObjectFile::end_symbols() const {
375 // The symbol table ends where the string table begins.
376 DataRefImpl ret;
377 std::memset(&ret, 0, sizeof(DataRefImpl));
378 ret.p = reinterpret_cast<intptr_t>(StringTable);
379 return symbol_iterator(SymbolRef(ret, this));
380 }
381
begin_sections() const382 ObjectFile::section_iterator COFFObjectFile::begin_sections() const {
383 DataRefImpl ret;
384 std::memset(&ret, 0, sizeof(DataRefImpl));
385 ret.p = reinterpret_cast<intptr_t>(SectionTable);
386 return section_iterator(SectionRef(ret, this));
387 }
388
end_sections() const389 ObjectFile::section_iterator COFFObjectFile::end_sections() const {
390 DataRefImpl ret;
391 std::memset(&ret, 0, sizeof(DataRefImpl));
392 ret.p = reinterpret_cast<intptr_t>(SectionTable + Header->NumberOfSections);
393 return section_iterator(SectionRef(ret, this));
394 }
395
getBytesInAddress() const396 uint8_t COFFObjectFile::getBytesInAddress() const {
397 return getArch() == Triple::x86_64 ? 8 : 4;
398 }
399
getFileFormatName() const400 StringRef COFFObjectFile::getFileFormatName() const {
401 switch(Header->Machine) {
402 case COFF::IMAGE_FILE_MACHINE_I386:
403 return "COFF-i386";
404 case COFF::IMAGE_FILE_MACHINE_AMD64:
405 return "COFF-x86-64";
406 default:
407 return "COFF-<unknown arch>";
408 }
409 }
410
getArch() const411 unsigned COFFObjectFile::getArch() const {
412 switch(Header->Machine) {
413 case COFF::IMAGE_FILE_MACHINE_I386:
414 return Triple::x86;
415 case COFF::IMAGE_FILE_MACHINE_AMD64:
416 return Triple::x86_64;
417 default:
418 return Triple::UnknownArch;
419 }
420 }
421
getSection(int32_t index,const coff_section * & Result) const422 error_code COFFObjectFile::getSection(int32_t index,
423 const coff_section *&Result) const {
424 // Check for special index values.
425 if (index == COFF::IMAGE_SYM_UNDEFINED ||
426 index == COFF::IMAGE_SYM_ABSOLUTE ||
427 index == COFF::IMAGE_SYM_DEBUG)
428 Result = NULL;
429 else if (index > 0 && index <= Header->NumberOfSections)
430 // We already verified the section table data, so no need to check again.
431 Result = SectionTable + (index - 1);
432 else
433 return object_error::parse_failed;
434 return object_error::success;
435 }
436
getString(uint32_t offset,StringRef & Result) const437 error_code COFFObjectFile::getString(uint32_t offset,
438 StringRef &Result) const {
439 if (StringTableSize <= 4)
440 // Tried to get a string from an empty string table.
441 return object_error::parse_failed;
442 if (offset >= StringTableSize)
443 return object_error::unexpected_eof;
444 Result = StringRef(StringTable + offset);
445 return object_error::success;
446 }
447
448 namespace llvm {
449
createCOFFObjectFile(MemoryBuffer * Object)450 ObjectFile *ObjectFile::createCOFFObjectFile(MemoryBuffer *Object) {
451 error_code ec;
452 return new COFFObjectFile(Object, ec);
453 }
454
455 } // end namespace llvm
456