[lld] r199973 - [ELF] Customize a relocation table output format (rel / rela).
Simon Atanasyan
simon at atanasyan.com
Thu Jan 23 21:21:22 PST 2014
Author: atanasyan
Date: Thu Jan 23 23:21:21 2014
New Revision: 199973
URL: http://llvm.org/viewvc/llvm-project?rev=199973&view=rev
Log:
[ELF] Customize a relocation table output format (rel / rela).
Add new virtual virtual function `isRelaOutputFormat` to the
`ELFLinkingContext` class. Call this function everywhere we need to
select a relocation table format.
Patch reviewed by Shankar Easwaran and Rui Ueyama.
Added:
lld/trunk/test/elf/Mips/exe-dynamic.test
Modified:
lld/trunk/include/lld/ReaderWriter/ELFLinkingContext.h
lld/trunk/lib/ReaderWriter/ELF/DefaultLayout.h
lld/trunk/lib/ReaderWriter/ELF/ExecutableWriter.h
lld/trunk/lib/ReaderWriter/ELF/Mips/MipsLinkingContext.h
lld/trunk/lib/ReaderWriter/ELF/SectionChunks.h
lld/trunk/test/elf/Mips/exe-fileheader.test
lld/trunk/test/elf/Mips/r26.test
Modified: lld/trunk/include/lld/ReaderWriter/ELFLinkingContext.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/include/lld/ReaderWriter/ELFLinkingContext.h?rev=199973&r1=199972&r2=199973&view=diff
==============================================================================
--- lld/trunk/include/lld/ReaderWriter/ELFLinkingContext.h (original)
+++ lld/trunk/include/lld/ReaderWriter/ELFLinkingContext.h Thu Jan 23 23:21:21 2014
@@ -93,6 +93,9 @@ public:
static std::unique_ptr<ELFLinkingContext> create(llvm::Triple);
+ /// \brief Use Elf_Rela format to output relocation tables.
+ virtual bool isRelaOutputFormat() const { return true; }
+
/// \brief Does this relocation belong in the dynamic plt relocation table?
///
/// This table holds all of the relocations used for delayed symbol binding.
Modified: lld/trunk/lib/ReaderWriter/ELF/DefaultLayout.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/ELF/DefaultLayout.h?rev=199973&r1=199972&r2=199973&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/ELF/DefaultLayout.h (original)
+++ lld/trunk/lib/ReaderWriter/ELF/DefaultLayout.h Thu Jan 23 23:21:21 2014
@@ -270,7 +270,8 @@ public:
RelocationTable<ELFT> *getDynamicRelocationTable() {
if (!_dynamicRelocationTable) {
_dynamicRelocationTable.reset(new (_allocator) RelocationTable<ELFT>(
- _context, ".rela.dyn", ORDER_DYNAMIC_RELOCS));
+ _context, _context.isRelaOutputFormat() ? ".rela.dyn" : ".rel.dyn",
+ ORDER_DYNAMIC_RELOCS));
addSection(_dynamicRelocationTable.get());
}
return _dynamicRelocationTable.get();
@@ -280,7 +281,8 @@ public:
RelocationTable<ELFT> *getPLTRelocationTable() {
if (!_pltRelocationTable) {
_pltRelocationTable.reset(new (_allocator) RelocationTable<ELFT>(
- _context, ".rela.plt", ORDER_DYNAMIC_PLT_RELOCS));
+ _context, _context.isRelaOutputFormat() ? ".rela.plt" : ".rel.plt",
+ ORDER_DYNAMIC_PLT_RELOCS));
addSection(_pltRelocationTable.get());
}
return _pltRelocationTable.get();
Modified: lld/trunk/lib/ReaderWriter/ELF/ExecutableWriter.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/ELF/ExecutableWriter.h?rev=199973&r1=199972&r2=199973&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/ELF/ExecutableWriter.h (original)
+++ lld/trunk/lib/ReaderWriter/ELF/ExecutableWriter.h Thu Jan 23 23:21:21 2014
@@ -55,8 +55,13 @@ void ExecutableWriter<ELFT>::addDefaultA
_runtimeFile->addAbsoluteAtom("__preinit_array_end");
_runtimeFile->addAbsoluteAtom("__init_array_start");
_runtimeFile->addAbsoluteAtom("__init_array_end");
- _runtimeFile->addAbsoluteAtom("__rela_iplt_start");
- _runtimeFile->addAbsoluteAtom("__rela_iplt_end");
+ if (this->_context.isRelaOutputFormat()) {
+ _runtimeFile->addAbsoluteAtom("__rela_iplt_start");
+ _runtimeFile->addAbsoluteAtom("__rela_iplt_end");
+ } else {
+ _runtimeFile->addAbsoluteAtom("__rel_iplt_start");
+ _runtimeFile->addAbsoluteAtom("__rel_iplt_end");
+ }
_runtimeFile->addAbsoluteAtom("__fini_array_start");
_runtimeFile->addAbsoluteAtom("__fini_array_end");
}
@@ -111,7 +116,10 @@ template <class ELFT> void ExecutableWri
startEnd("preinit_array", ".preinit_array");
startEnd("init_array", ".init_array");
- startEnd("rela_iplt", ".rela.plt");
+ if (this->_context.isRelaOutputFormat())
+ startEnd("rela_iplt", ".rela.plt");
+ else
+ startEnd("rel_iplt", ".rel.plt");
startEnd("fini_array", ".fini_array");
assert(!(bssStartAtomIter == this->_layout->absoluteAtoms().end() ||
Modified: lld/trunk/lib/ReaderWriter/ELF/Mips/MipsLinkingContext.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/ELF/Mips/MipsLinkingContext.h?rev=199973&r1=199972&r2=199973&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/ELF/Mips/MipsLinkingContext.h (original)
+++ lld/trunk/lib/ReaderWriter/ELF/Mips/MipsLinkingContext.h Thu Jan 23 23:21:21 2014
@@ -45,6 +45,7 @@ public:
virtual StringRef entrySymbolName() const;
virtual StringRef getDefaultInterpreter() const;
virtual void addPasses(PassManager &pm);
+ virtual bool isRelaOutputFormat() const { return false; }
virtual bool isPLTRelocation(const DefinedAtom &, const Reference &r) const;
};
Modified: lld/trunk/lib/ReaderWriter/ELF/SectionChunks.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/ELF/SectionChunks.h?rev=199973&r1=199972&r2=199973&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/ELF/SectionChunks.h (original)
+++ lld/trunk/lib/ReaderWriter/ELF/SectionChunks.h Thu Jan 23 23:21:21 2014
@@ -900,22 +900,29 @@ private:
template <class ELFT> class RelocationTable : public Section<ELFT> {
public:
+ typedef llvm::object::Elf_Rel_Impl<ELFT, false> Elf_Rel;
typedef llvm::object::Elf_Rel_Impl<ELFT, true> Elf_Rela;
RelocationTable(const ELFLinkingContext &context, StringRef str,
int32_t order)
: Section<ELFT>(context, str), _symbolTable(nullptr) {
this->setOrder(order);
- this->_entSize = sizeof(Elf_Rela);
- this->_align2 = llvm::alignOf<Elf_Rela>();
- this->_type = SHT_RELA;
this->_flags = SHF_ALLOC;
+ if (context.isRelaOutputFormat()) {
+ this->_entSize = sizeof(Elf_Rela);
+ this->_align2 = llvm::alignOf<Elf_Rela>();
+ this->_type = SHT_RELA;
+ } else {
+ this->_entSize = sizeof(Elf_Rel);
+ this->_align2 = llvm::alignOf<Elf_Rel>();
+ this->_type = SHT_REL;
+ }
}
/// \returns the index of the relocation added.
uint32_t addRelocation(const DefinedAtom &da, const Reference &r) {
_relocs.emplace_back(&da, &r);
- this->_fsize = _relocs.size() * sizeof(Elf_Rela);
+ this->_fsize = _relocs.size() * this->_entSize;
this->_msize = this->_fsize;
return _relocs.size() - 1;
}
@@ -945,34 +952,52 @@ public:
}
virtual void write(ELFWriter *writer, llvm::FileOutputBuffer &buffer) {
- uint8_t *chunkBuffer = buffer.getBufferStart();
- uint8_t *dest = chunkBuffer + this->fileOffset();
+ uint8_t *dest = buffer.getBufferStart() + this->fileOffset();
for (const auto &rel : _relocs) {
- Elf_Rela *r = reinterpret_cast<Elf_Rela *>(dest);
- uint32_t index =
- _symbolTable ? _symbolTable->getSymbolTableIndex(rel.second->target())
- : (uint32_t) STN_UNDEF;
- r->setSymbolAndType(index, rel.second->kindValue());
- r->r_offset =
- writer->addressOfAtom(rel.first) + rel.second->offsetInAtom();
- r->r_addend = 0;
- // The addend is used only by relative relocations
- if (this->_context.isRelativeReloc(*rel.second))
- r->r_addend =
- writer->addressOfAtom(rel.second->target()) + rel.second->addend();
- dest += sizeof(Elf_Rela);
- DEBUG_WITH_TYPE("ELFRelocationTable",
- llvm::dbgs() << rel.second->kindValue()
- << " relocation at " << rel.first->name()
- << "@" << r->r_offset << " to "
- << rel.second->target()->name() << "@"
- << r->r_addend << "\n";);
+ if (this->_context.isRelaOutputFormat())
+ writeRela(writer, *reinterpret_cast<Elf_Rela *>(dest), *rel.first,
+ *rel.second);
+ else
+ writeRel(writer, *reinterpret_cast<Elf_Rel *>(dest), *rel.first,
+ *rel.second);
+ dest += this->_entSize;
}
}
private:
std::vector<std::pair<const DefinedAtom *, const Reference *> > _relocs;
const DynamicSymbolTable<ELFT> *_symbolTable;
+
+ void writeRela(ELFWriter *writer, Elf_Rela &r, const DefinedAtom &atom,
+ const Reference &ref) {
+ uint32_t index =
+ _symbolTable ? _symbolTable->getSymbolTableIndex(ref.target())
+ : (uint32_t)STN_UNDEF;
+ r.setSymbolAndType(index, ref.kindValue());
+ r.r_offset = writer->addressOfAtom(&atom) + ref.offsetInAtom();
+ r.r_addend = 0;
+ // The addend is used only by relative relocations
+ if (this->_context.isRelativeReloc(ref))
+ r.r_addend = writer->addressOfAtom(ref.target()) + ref.addend();
+ DEBUG_WITH_TYPE("ELFRelocationTable",
+ llvm::dbgs() << ref.kindValue() << " relocation at "
+ << atom.name() << "@" << r.r_offset << " to "
+ << ref.target()->name() << "@" << r.r_addend
+ << "\n";);
+ }
+
+ void writeRel(ELFWriter *writer, Elf_Rel &r, const DefinedAtom &atom,
+ const Reference &ref) {
+ uint32_t index =
+ _symbolTable ? _symbolTable->getSymbolTableIndex(ref.target())
+ : (uint32_t)STN_UNDEF;
+ r.setSymbolAndType(index, ref.kindValue());
+ r.r_offset = writer->addressOfAtom(&atom) + ref.offsetInAtom();
+ DEBUG_WITH_TYPE("ELFRelocationTable",
+ llvm::dbgs() << ref.kindValue() << " relocation at "
+ << atom.name() << "@" << r.r_offset << " to "
+ << ref.target()->name() << "\n";);
+ }
};
template <class ELFT> class HashSection;
@@ -1017,6 +1042,8 @@ public:
}
virtual void createDefaultEntries() {
+ bool isRela = this->_context.isRelaOutputFormat();
+
Elf_Dyn dyn;
dyn.d_un.d_val = 0;
@@ -1035,11 +1062,11 @@ public:
dyn.d_tag = DT_FINI_ARRAYSZ;
_dt_fini_arraysz = addEntry(dyn);
if (_layout->hasDynamicRelocationTable()) {
- dyn.d_tag = DT_RELA;
+ dyn.d_tag = isRela ? DT_RELA : DT_REL;
_dt_rela = addEntry(dyn);
- dyn.d_tag = DT_RELASZ;
+ dyn.d_tag = isRela ? DT_RELASZ : DT_RELSZ;
_dt_relasz = addEntry(dyn);
- dyn.d_tag = DT_RELAENT;
+ dyn.d_tag = isRela ? DT_RELAENT : DT_RELENT;
_dt_relaent = addEntry(dyn);
}
if (_layout->hasPLTRelocationTable()) {
@@ -1048,7 +1075,7 @@ public:
dyn.d_tag = DT_PLTGOT;
_dt_pltgot = addEntry(dyn);
dyn.d_tag = DT_PLTREL;
- dyn.d_un.d_val = DT_RELA;
+ dyn.d_un.d_val = isRela ? DT_RELA : DT_REL;
_dt_pltrel = addEntry(dyn);
dyn.d_un.d_val = 0;
dyn.d_tag = DT_JMPREL;
Added: lld/trunk/test/elf/Mips/exe-dynamic.test
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/elf/Mips/exe-dynamic.test?rev=199973&view=auto
==============================================================================
--- lld/trunk/test/elf/Mips/exe-dynamic.test (added)
+++ lld/trunk/test/elf/Mips/exe-dynamic.test Thu Jan 23 23:21:21 2014
@@ -0,0 +1,48 @@
+# Check MIPS specific tags in the dynamic table in case executable linking.
+
+# Build shared library
+# RUN: llvm-mc -triple=mipsel -filetype=obj -relocation-model=pic \
+# RUN: -o=%t-obj %p/Inputs/ext.s
+# RUN: lld -flavor gnu -target mipsel -shared -o %t-so %t-obj
+
+# Build executable
+# RUN: llvm-mc -triple=mipsel -filetype=obj -o=%t-obj %s
+# RUN: lld -flavor gnu -target mipsel -e glob -o %t-exe %t-obj %t-so
+# RUN: llvm-readobj -dynamic-table %t-exe | FileCheck %s
+
+# CHECK: Format: ELF32-mips
+# CHECK: Arch: mipsel
+# CHECK: AddressSize: 32bit
+# CHECK: LoadName:
+# CHECK: DynamicSection [ (20 entries)
+# CHECK: Tag Type Name/Value
+# CHECK: 0x00000004 HASH 0x400110
+# CHECK: 0x00000005 STRTAB 0x400144
+# CHECK: 0x00000006 SYMTAB 0x400124
+# CHECK: 0x0000000A STRSZ 30 (bytes)
+# CHECK: 0x0000000B SYMENT 16 (bytes)
+# CHECK: 0x0000001A FINI_ARRAY 0x0
+# CHECK: 0x0000001C FINI_ARRAYSZ 0 (bytes)
+# CHECK: 0x00000002 PLTRELSZ 8 (bytes)
+# CHECK: 0x00000003 PLTGOT 0x402000
+# CHECK: 0x00000014 PLTREL REL
+# CHECK: 0x00000017 JMPREL 0x400162
+# CHECK: 0x70000001 MIPS_RLD_VERSION 1
+# CHECK: 0x70000005 MIPS_FLAGS 0x2
+# CHECK: 0x70000006 MIPS_BASE_ADDRESS 0x400000
+# CHECK: 0x7000000A MIPS_LOCAL_GOTNO 2
+# CHECK: 0x70000011 MIPS_SYMTABNO 2
+# CHECK: 0x70000013 MIPS_GOTSYM 0x2
+# CHECK: 0x00000001 NEEDED SharedLibrary (exe-dynamic.test.{{.*}})
+# CHECK: 0x00000000 NULL 0x0
+# CHECK: ]
+
+ .abicalls
+ .global glob
+ .ent glob
+loc:
+ jal ext1
+glob:
+ jal loc
+ jal glob
+ .end glob
Modified: lld/trunk/test/elf/Mips/exe-fileheader.test
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/elf/Mips/exe-fileheader.test?rev=199973&r1=199972&r2=199973&view=diff
==============================================================================
--- lld/trunk/test/elf/Mips/exe-fileheader.test (original)
+++ lld/trunk/test/elf/Mips/exe-fileheader.test Thu Jan 23 23:21:21 2014
@@ -27,7 +27,7 @@
# CHECK: Type: Executable (0x2)
# CHECK: Machine: EM_MIPS (0x8)
# CHECK: Version: 1
-# CHECK: Entry: 0x4001B0
+# CHECK: Entry: 0x4001A0
# CHECK: ProgramHeaderOffset: 0x34
# CHECK: SectionHeaderOffset: 0x2268
# CHECK: Flags [ (0x70001005)
Modified: lld/trunk/test/elf/Mips/r26.test
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/elf/Mips/r26.test?rev=199973&r1=199972&r2=199973&view=diff
==============================================================================
--- lld/trunk/test/elf/Mips/r26.test (original)
+++ lld/trunk/test/elf/Mips/r26.test Thu Jan 23 23:21:21 2014
@@ -24,7 +24,7 @@
# Executable file has the only relocation for external symbol
# EXE-REL: Relocations [
-# EXE-REL: Section (5) .rela.plt {
+# EXE-REL: Section (5) .rel.plt {
# EXE-REL: 0x402008 R_MIPS_JUMP_SLOT ext1 0x0
# EXE-REL: }
# EXE-REL: ]
@@ -32,32 +32,32 @@
# EXE: Disassembly of section .plt:
# EXE: .plt:
# PLTA entry. Points to the .got.plt[1]
-# EXE: 400190: 40 00 0f 3c lui $15, 64
-# EXE: 400194: 08 20 f9 8d lw $25, 8200($15)
-# EXE: 400198: 08 00 20 03 jr $25
-# EXE: 40019c: 08 20 f8 25 addiu $24, $15, 8200
+# EXE: 400180: 40 00 0f 3c lui $15, 64
+# EXE: 400184: 08 20 f9 8d lw $25, 8200($15)
+# EXE: 400188: 08 00 20 03 jr $25
+# EXE: 40018c: 08 20 f8 25 addiu $24, $15, 8200
# EXE: Disassembly of section .text:
# EXE: glob:
-# EXE: 4001a0: 09 f8 20 03 jalr $25
-# EXE: 4001a4: 00 00 00 00 nop
+# EXE: 400190: 09 f8 20 03 jalr $25
+# EXE: 400194: 00 00 00 00 nop
#
# Jump to 'loc' label address
-# EXE: 4001a8: 6c 00 10 0c jal 4194736
-# EXE: 4001ac: 00 00 00 00 nop
+# EXE: 400198: 6c 00 10 0c jal 4194736
+# EXE: 40019c: 00 00 00 00 nop
#
# EXE: loc:
# Jump to 'glob' label address
-# EXE: 4001b0: 68 00 10 0c jal 4194720
-# EXE: 4001b4: 00 00 00 00 nop
+# EXE: 4001a0: 64 00 10 0c jal 4194704
+# EXE: 4001a4: 00 00 00 00 nop
#
# Jump to the first PLT entry (.plt + 32) for ext1 entry
-# EXE: 4001b8: 64 00 10 0c jal 4194704
-# EXE: 4001bc: 00 00 00 00 nop
+# EXE: 4001a8: 60 00 10 0c jal 4194688
+# EXE: 4001ac: 00 00 00 00 nop
# EXE: Sections:
# EXE: Idx Name Size Address Type
-# EXE: 6 .plt 00000030 0000000000400170 TEXT DATA
+# EXE: 6 .plt 00000030 0000000000400160 TEXT DATA
# EXE: 10 .got.plt 0000000c 0000000000402000 DATA
.abicalls
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