[lld] r240262 - [Mips] Reject position-dependent relocations in case of shared library linking
Simon Atanasyan
simon at atanasyan.com
Mon Jun 22 02:26:20 PDT 2015
Author: atanasyan
Date: Mon Jun 22 04:26:20 2015
New Revision: 240262
URL: http://llvm.org/viewvc/llvm-project?rev=240262&view=rev
Log:
[Mips] Reject position-dependent relocations in case of shared library linking
Added:
lld/trunk/test/elf/Mips/validate-rel-01.test
Modified:
lld/trunk/lib/ReaderWriter/ELF/Mips/MipsRelocationPass.cpp
Modified: lld/trunk/lib/ReaderWriter/ELF/Mips/MipsRelocationPass.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/ELF/Mips/MipsRelocationPass.cpp?rev=240262&r1=240261&r2=240262&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/ELF/Mips/MipsRelocationPass.cpp (original)
+++ lld/trunk/lib/ReaderWriter/ELF/Mips/MipsRelocationPass.cpp Mon Jun 22 04:26:20 2015
@@ -379,8 +379,12 @@ private:
/// \brief Collect information about the reference to use it
/// later in the handleReference() routine.
- void collectReferenceInfo(const MipsELFDefinedAtom<ELFT> &atom,
- Reference &ref);
+ std::error_code collectReferenceInfo(const MipsELFDefinedAtom<ELFT> &atom,
+ Reference &ref);
+
+ /// \brief Check that the relocation is valid for the current linking mode.
+ std::error_code validateRelocation(const DefinedAtom &atom,
+ const Reference &ref) const;
void handlePlain(const MipsELFDefinedAtom<ELFT> &atom, Reference &ref);
void handle26(const MipsELFDefinedAtom<ELFT> &atom, Reference &ref);
@@ -430,9 +434,11 @@ RelocationPass<ELFT>::RelocationPass(Mip
template <typename ELFT>
std::error_code RelocationPass<ELFT>::perform(SimpleFile &mf) {
for (const auto &atom : mf.defined())
- for (const auto &ref : *atom)
- collectReferenceInfo(*cast<MipsELFDefinedAtom<ELFT>>(atom),
- const_cast<Reference &>(*ref));
+ for (const auto &ref : *atom) {
+ const auto &da = *cast<MipsELFDefinedAtom<ELFT>>(atom);
+ if (auto ec = collectReferenceInfo(da, const_cast<Reference &>(*ref)))
+ return ec;
+ }
// Process all references.
for (const auto &atom : mf.defined())
@@ -625,19 +631,23 @@ static bool isConstrainSym(const MipsELF
}
template <typename ELFT>
-void RelocationPass<ELFT>::collectReferenceInfo(
- const MipsELFDefinedAtom<ELFT> &atom, Reference &ref) {
+std::error_code
+RelocationPass<ELFT>::collectReferenceInfo(const MipsELFDefinedAtom<ELFT> &atom,
+ Reference &ref) {
if (!ref.target())
- return;
+ return std::error_code();
if (ref.kindNamespace() != Reference::KindNamespace::ELF)
- return;
+ return std::error_code();
auto refKind = ref.kindValue();
if (refKind == R_MIPS_EH && this->_ctx.mipsPcRelEhRel())
ref.setKindValue(R_MIPS_PC32);
+ if (auto ec = validateRelocation(atom, ref))
+ return ec;
+
if (!isConstrainSym(atom, refKind))
- return;
+ return std::error_code();
if (mightBeDynamic(atom, refKind))
_rel32Candidates.push_back(&ref);
@@ -652,6 +662,56 @@ void RelocationPass<ELFT>::collectRefere
refKind != R_MICROMIPS_CALL_HI16 && refKind != R_MICROMIPS_CALL_LO16 &&
refKind != R_MIPS_EH)
_requiresPtrEquality.insert(ref.target());
+ return std::error_code();
+}
+
+static std::error_code
+make_reject_for_shared_lib_reloc_error(const ELFLinkingContext &ctx,
+ const DefinedAtom &atom,
+ const Reference &ref) {
+ StringRef kindValStr = "unknown";
+ ctx.registry().referenceKindToString(ref.kindNamespace(), ref.kindArch(),
+ ref.kindValue(), kindValStr);
+
+ return make_dynamic_error_code(Twine(kindValStr) + " (" +
+ Twine(ref.kindValue()) +
+ ") relocation cannot be used "
+ "when making a shared object, recompile " +
+ atom.file().path() + " with -fPIC");
+}
+
+template <typename ELFT>
+std::error_code
+RelocationPass<ELFT>::validateRelocation(const DefinedAtom &atom,
+ const Reference &ref) const {
+ if (this->_ctx.getOutputELFType() != ET_DYN)
+ return std::error_code();
+ if (!ref.target())
+ return std::error_code();
+
+ switch (ref.kindValue()) {
+ case R_MIPS16_HI16:
+ case R_MIPS_HI16:
+ case R_MIPS_HIGHER:
+ case R_MIPS_HIGHEST:
+ case R_MICROMIPS_HI16:
+ case R_MICROMIPS_HIGHER:
+ case R_MICROMIPS_HIGHEST:
+ // For shared object we accepts "high" relocations
+ // against the "_gp_disp" symbol only.
+ if (ref.target()->name() != "_gp_disp")
+ return make_reject_for_shared_lib_reloc_error(this->_ctx, atom, ref);
+ break;
+ case R_MIPS16_26:
+ case R_MIPS_26:
+ case R_MICROMIPS_26_S1:
+ // These relocations are position dependent
+ // and not acceptable in a shared object.
+ return make_reject_for_shared_lib_reloc_error(this->_ctx, atom, ref);
+ default:
+ break;
+ }
+ return std::error_code();
}
template <typename ELFT>
Added: lld/trunk/test/elf/Mips/validate-rel-01.test
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/elf/Mips/validate-rel-01.test?rev=240262&view=auto
==============================================================================
--- lld/trunk/test/elf/Mips/validate-rel-01.test (added)
+++ lld/trunk/test/elf/Mips/validate-rel-01.test Mon Jun 22 04:26:20 2015
@@ -0,0 +1,82 @@
+# Check that the linker does not accept position-dependent relocations
+# in case of shared library linking.
+
+# RUN: yaml2obj -format=elf -docnum 1 %s > %t-hi.o
+# RUN: not lld -flavor gnu -target mipsel -shared -o %t.so %t-hi.o 2>&1 \
+# RUN: | FileCheck -check-prefix=RHI %s
+
+# RHI: R_MIPS_HI16 (5) relocation cannot be used when making a shared object, recompile {{.*}}validate-rel-01.test.tmp-hi.o with -fPIC
+
+# RUN: yaml2obj -format=elf -docnum 2 %s > %t-26.o
+# RUN: not lld -flavor gnu -target mipsel -shared -o %t.so %t-26.o 2>&1 \
+# RUN: | FileCheck -check-prefix=R26 %s
+
+# R26: R_MIPS_26 (4) relocation cannot be used when making a shared object, recompile {{.*}}validate-rel-01.test.tmp-26.o with -fPIC
+
+---
+FileHeader:
+ Class: ELFCLASS32
+ Data: ELFDATA2LSB
+ Type: ET_REL
+ Machine: EM_MIPS
+ Flags: [EF_MIPS_CPIC, EF_MIPS_ABI_O32, EF_MIPS_ARCH_32]
+
+Sections:
+ - Name: .text
+ Type: SHT_PROGBITS
+ Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+ AddressAlign: 16
+ Size: 4
+
+ - Name: .rel.text
+ Type: SHT_REL
+ Link: .symtab
+ AddressAlign: 4
+ Info: .text
+ Relocations:
+ - Offset: 0
+ Symbol: T0
+ Type: R_MIPS_HI16
+ - Offset: 0
+ Symbol: T0
+ Type: R_MIPS_LO16
+
+Symbols:
+ Global:
+ - Name: T0
+ Type: STT_FUNC
+ Section: .text
+ Size: 4
+
+---
+FileHeader:
+ Class: ELFCLASS32
+ Data: ELFDATA2LSB
+ Type: ET_REL
+ Machine: EM_MIPS
+ Flags: [EF_MIPS_CPIC, EF_MIPS_ABI_O32, EF_MIPS_ARCH_32]
+
+Sections:
+ - Name: .text
+ Type: SHT_PROGBITS
+ Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+ AddressAlign: 16
+ Size: 4
+
+ - Name: .rel.text
+ Type: SHT_REL
+ Link: .symtab
+ AddressAlign: 4
+ Info: .text
+ Relocations:
+ - Offset: 0
+ Symbol: T1
+ Type: R_MIPS_26
+
+Symbols:
+ Global:
+ - Name: T1
+ Type: STT_FUNC
+ Section: .text
+ Size: 4
+...
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