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Object, COFF: Increase code reuse 

Split getObject's smarts into checkOffset, use this to replace the
handwritten check in getSectionContents.  Similarly, replace checks in
section_rel_begin/section_rel_end with getNumberOfRelocations.

No functionality change intended.

llvm-svn: 221873
This commit is contained in:
David Majnemer 2014-11-13 08:46:37 +00:00
parent e0eb086dd4
commit e830c60d89
1 changed files with 32 additions and 24 deletions
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56
llvm/lib/Object/COFFObjectFile.cpp
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@ -39,6 +39,16 @@ static bool checkSize(MemoryBufferRef M, std::error_code &EC, uint64_t Size) {
return true;
}
static std::error_code checkOffset(MemoryBufferRef M, uintptr_t Addr,
const size_t Size) {
if (Addr + Size < Addr || Addr + Size < Size ||
Addr + Size > uintptr_t(M.getBufferEnd()) ||
Addr < uintptr_t(M.getBufferStart())) {
return object_error::unexpected_eof;
}
return object_error::success;
}
// Sets Obj unless any bytes in [addr, addr + size) fall outsize of m.
// Returns unexpected_eof if error.
template <typename T>
@ -46,11 +56,8 @@ static std::error_code getObject(const T *&Obj, MemoryBufferRef M,
const void *Ptr,
const size_t Size = sizeof(T)) {
uintptr_t Addr = uintptr_t(Ptr);
if (Addr + Size < Addr || Addr + Size < Size ||
Addr + Size > uintptr_t(M.getBufferEnd()) ||
Addr < uintptr_t(M.getBufferStart())) {
return object_error::unexpected_eof;
}
if (std::error_code EC = checkOffset(M, Addr, Size))
return EC;
Obj = reinterpret_cast<const T *>(Addr);
return object_error::success;
}
@ -385,10 +392,26 @@ bool COFFObjectFile::sectionContainsSymbol(DataRefImpl SecRef,
return SecNumber == Symb.getSectionNumber();
}
static uint32_t getNumberOfRelocations(const coff_section *Sec,
MemoryBufferRef M, const uint8_t *base) {
// The field for the number of relocations in COFF section table is only
// 16-bit wide. If a section has more than 65535 relocations, 0xFFFF is set to
// NumberOfRelocations field, and the actual relocation count is stored in the
// VirtualAddress field in the first relocation entry.
if (Sec->hasExtendedRelocations()) {
const coff_relocation *FirstReloc;
if (getObject(FirstReloc, M, reinterpret_cast<const coff_relocation*>(
base + Sec->PointerToRelocations)))
return 0;
return FirstReloc->VirtualAddress;
}
return Sec->NumberOfRelocations;
}
relocation_iterator COFFObjectFile::section_rel_begin(DataRefImpl Ref) const {
const coff_section *Sec = toSec(Ref);
DataRefImpl Ret;
if (Sec->NumberOfRelocations == 0) {
if (getNumberOfRelocations(Sec, Data, base()) == 0) {
Ret.p = 0;
} else {
auto begin = reinterpret_cast<const coff_relocation*>(
@ -403,24 +426,10 @@ relocation_iterator COFFObjectFile::section_rel_begin(DataRefImpl Ref) const {
return relocation_iterator(RelocationRef(Ret, this));
}
static uint32_t getNumberOfRelocations(const coff_section *Sec,
const uint8_t *base) {
// The field for the number of relocations in COFF section table is only
// 16-bit wide. If a section has more than 65535 relocations, 0xFFFF is set to
// NumberOfRelocations field, and the actual relocation count is stored in the
// VirtualAddress field in the first relocation entry.
if (Sec->hasExtendedRelocations()) {
auto *FirstReloc = reinterpret_cast<const coff_relocation*>(
base + Sec->PointerToRelocations);
return FirstReloc->VirtualAddress;
}
return Sec->NumberOfRelocations;
}
relocation_iterator COFFObjectFile::section_rel_end(DataRefImpl Ref) const {
const coff_section *Sec = toSec(Ref);
DataRefImpl Ret;
if (Sec->NumberOfRelocations == 0) {
if (getNumberOfRelocations(Sec, Data, base()) == 0) {
Ret.p = 0;
} else {
auto begin = reinterpret_cast<const coff_relocation*>(
@ -430,7 +439,7 @@ relocation_iterator COFFObjectFile::section_rel_end(DataRefImpl Ref) const {
// relocations.
begin++;
}
uint32_t NumReloc = getNumberOfRelocations(Sec, base());
uint32_t NumReloc = getNumberOfRelocations(Sec, Data, base());
Ret.p = reinterpret_cast<uintptr_t>(begin + NumReloc);
}
return relocation_iterator(RelocationRef(Ret, this));
@ -956,8 +965,7 @@ COFFObjectFile::getSectionContents(const coff_section *Sec,
// data, as there's nothing that says that is not allowed.
uintptr_t ConStart = uintptr_t(base()) + Sec->PointerToRawData;
uint32_t SectionSize = getSectionSize(Sec);
uintptr_t ConEnd = ConStart + SectionSize;
if (ConEnd > uintptr_t(Data.getBufferEnd()))
if (checkOffset(Data, ConStart, SectionSize))
return object_error::parse_failed;
Res = makeArrayRef(reinterpret_cast<const uint8_t *>(ConStart), SectionSize);
return object_error::success;