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[llvm-readobj][ELF] Show MIPS GOT content when there is another zero-sized section at the same address

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It is possible to have .got section and one or more zero-sized section
at the same address. This patch first checks that GOT (or GOT PLT)
section should have non-zero size using corresponding dynamic tags. Then
it looks up not empty section at the specified address.

Differential Revision: http://reviews.llvm.org/D16968

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260245 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Simon Atanasyan 2016-02-09 18:45:35 +00:00
parent 23b546ba0d
commit 30b32053a4
3 changed files with 70 additions and 40 deletions
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BIN
test/tools/llvm-readobj/Inputs/got-over.exe.elf-mips Executable file
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45
test/tools/llvm-readobj/mips-got-overlapped.test Normal file
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@ -0,0 +1,45 @@
# Check that llvm-readobj -mips-plt-got correctly shows .got section
# content if there are some other zero-sized sections with the same
# address as the .got. got-over.exe.elf-mips has zero-sized .data
# section at the same offset .got section.
RUN: llvm-readobj -mips-plt-got %p/Inputs/got-over.exe.elf-mips | FileCheck %s
GOT-OBJ: Cannot find PLTGOT dynamic table tag.
CHECK: Primary GOT {
CHECK-NEXT: Canonical gp value: 0x418270
CHECK-NEXT: Reserved entries [
CHECK-NEXT: Entry {
CHECK-NEXT: Address: 0x410280
CHECK-NEXT: Access: -32752
CHECK-NEXT: Initial: 0x0
CHECK-NEXT: Purpose: Lazy resolver
CHECK-NEXT: }
CHECK-NEXT: Entry {
CHECK-NEXT: Address: 0x410284
CHECK-NEXT: Access: -32748
CHECK-NEXT: Initial: 0x80000000
CHECK-NEXT: Purpose: Module pointer (GNU extension)
CHECK-NEXT: }
CHECK-NEXT: ]
CHECK-NEXT: Local entries [
CHECK-NEXT: Entry {
CHECK-NEXT: Address: 0x410288
CHECK-NEXT: Access: -32744
CHECK-NEXT: Initial: 0x4001B8
CHECK-NEXT: }
CHECK-NEXT: ]
CHECK-NEXT: Global entries [
CHECK-NEXT: Entry {
CHECK-NEXT: Address: 0x41028C
CHECK-NEXT: Access: -32740
CHECK-NEXT: Initial: 0x0
CHECK-NEXT: Value: 0x0
CHECK-NEXT: Type: None
CHECK-NEXT: Section: Undefined
CHECK-NEXT: Name: _foo
CHECK-NEXT: }
CHECK-NEXT: ]
CHECK-NEXT: Number of TLS and multi-GOT entries: 0
CHECK-NEXT: }

65
tools/llvm-readobj/ELFDumper.cpp
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@ -497,10 +497,10 @@ getSectionNameIndex(const ELFO &Obj, const typename ELFO::Elf_Sym *Symbol,
}
template <class ELFO>
static const typename ELFO::Elf_Shdr *findSectionByAddress(const ELFO *Obj,
uint64_t Addr) {
static const typename ELFO::Elf_Shdr *
findNotEmptySectionByAddress(const ELFO *Obj, uint64_t Addr) {
for (const auto &Shdr : Obj->sections())
if (Shdr.sh_addr == Addr)
if (Shdr.sh_addr == Addr && Shdr.sh_size > 0)
return &Shdr;
return nullptr;
}
@ -1865,23 +1865,6 @@ template <class ELFT> void MipsGOTParser<ELFT>::parseGOT() {
return;
}
const Elf_Shdr *GOTShdr = findSectionByAddress(Obj, *DtPltGot);
if (!GOTShdr) {
W.startLine() << "There is no .got section in the file.\n";
return;
}
ErrorOr<ArrayRef<uint8_t>> GOT = Obj->getSectionContents(GOTShdr);
if (!GOT) {
W.startLine() << "The .got section is empty.\n";
return;
}
if (*DtLocalGotNum > getGOTTotal(*GOT)) {
W.startLine() << "MIPS_LOCAL_GOTNO exceeds a number of GOT entries.\n";
return;
}
const Elf_Shdr *DynSymSec = Dumper->getDotDynSymSec();
ErrorOr<StringRef> StrTable = Obj->getStringTableForSymtab(*DynSymSec);
error(StrTable.getError());
@ -1889,18 +1872,26 @@ template <class ELFT> void MipsGOTParser<ELFT>::parseGOT() {
const Elf_Sym *DynSymEnd = Obj->symbol_end(DynSymSec);
std::size_t DynSymTotal = std::size_t(std::distance(DynSymBegin, DynSymEnd));
if (*DtGotSym > DynSymTotal) {
W.startLine() << "MIPS_GOTSYM exceeds a number of dynamic symbols.\n";
return;
}
if (*DtGotSym > DynSymTotal)
report_fatal_error("MIPS_GOTSYM exceeds a number of dynamic symbols");
std::size_t GlobalGotNum = DynSymTotal - *DtGotSym;
if (*DtLocalGotNum + GlobalGotNum > getGOTTotal(*GOT)) {
W.startLine() << "Number of global GOT entries exceeds the size of GOT.\n";
if (*DtLocalGotNum + GlobalGotNum == 0) {
W.startLine() << "GOT is empty.\n";
return;
}
const Elf_Shdr *GOTShdr = findNotEmptySectionByAddress(Obj, *DtPltGot);
if (!GOTShdr)
report_fatal_error("There is no not empty GOT section at 0x" +
Twine::utohexstr(*DtPltGot));
ErrorOr<ArrayRef<uint8_t>> GOT = Obj->getSectionContents(GOTShdr);
if (*DtLocalGotNum + GlobalGotNum > getGOTTotal(*GOT))
report_fatal_error("Number of GOT entries exceeds the size of GOT section");
const GOTEntry *GotBegin = makeGOTIter(*GOT, 0);
const GOTEntry *GotLocalEnd = makeGOTIter(*GOT, *DtLocalGotNum);
const GOTEntry *It = GotBegin;
@ -1957,22 +1948,16 @@ template <class ELFT> void MipsGOTParser<ELFT>::parsePLT() {
return;
}
const Elf_Shdr *PLTShdr = findSectionByAddress(Obj, *DtMipsPltGot);
if (!PLTShdr) {
W.startLine() << "There is no .got.plt section in the file.\n";
return;
}
const Elf_Shdr *PLTShdr = findNotEmptySectionByAddress(Obj, *DtMipsPltGot);
if (!PLTShdr)
report_fatal_error("There is no not empty PLTGOT section at 0x " +
Twine::utohexstr(*DtMipsPltGot));
ErrorOr<ArrayRef<uint8_t>> PLT = Obj->getSectionContents(PLTShdr);
if (!PLT) {
W.startLine() << "The .got.plt section is empty.\n";
return;
}
const Elf_Shdr *PLTRelShdr = findSectionByAddress(Obj, *DtJmpRel);
if (!PLTShdr) {
W.startLine() << "There is no .rel.plt section in the file.\n";
return;
}
const Elf_Shdr *PLTRelShdr = findNotEmptySectionByAddress(Obj, *DtJmpRel);
if (!PLTRelShdr)
report_fatal_error("There is no not empty RELPLT section at 0x" +
Twine::utohexstr(*DtJmpRel));
ErrorOr<const Elf_Shdr *> SymTableOrErr =
Obj->getSection(PLTRelShdr->sh_link);
error(SymTableOrErr.getError());