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[ARM] Add needed symbols during dynamic executable linking

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These include _GLOBAL_OFFSET_TABLE_ and _DYNAMIC.

llvm-svn: 237791
This commit is contained in:
Denis Protivensky 2015-05-20 13:39:33 +00:00
parent 196390e8af
commit 56b12d75bf
2 changed files with 74 additions and 0 deletions
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15
lld/lib/ReaderWriter/ELF/ARM/ARMExecutableWriter.h
View File

@ -17,6 +17,7 @@
namespace {
const char *gotSymbol = "_GLOBAL_OFFSET_TABLE_";
const char *dynamicSymbol = "_DYNAMIC";
}
namespace lld {
@ -53,6 +54,13 @@ ARMExecutableWriter::ARMExecutableWriter(ARMLinkingContext &ctx,
void ARMExecutableWriter::createImplicitFiles(
std::vector<std::unique_ptr<File>> &result) {
ExecutableWriter::createImplicitFiles(result);
// Add default atoms for ARM.
if (_ctx.isDynamic()) {
auto file = llvm::make_unique<RuntimeFile<ELF32LE>>(_ctx, "ARM exec file");
file->addAbsoluteAtom(gotSymbol);
file->addAbsoluteAtom(dynamicSymbol);
result.push_back(std::move(file));
}
}
void ARMExecutableWriter::finalizeDefaultAtomValues() {
@ -68,6 +76,13 @@ void ARMExecutableWriter::finalizeDefaultAtomValues() {
gotAtom->_virtualAddr = 0;
}
if (auto *dynamicAtom = _armLayout.findAbsoluteAtom(dynamicSymbol)) {
if (auto dynamicSection = _armLayout.findOutputSection(".dynamic"))
dynamicAtom->_virtualAddr = dynamicSection->virtualAddr();
else
dynamicAtom->_virtualAddr = 0;
}
// Set required by gcc libc __ehdr_start symbol with pointer to ELF header
if (auto ehdr = _armLayout.findAbsoluteAtom("__ehdr_start"))
ehdr->_virtualAddr = _elfHeader->virtualAddr();

59
lld/test/elf/ARM/dynamic-symbols.test Normal file
View File

@ -0,0 +1,59 @@
# Check that proper dynamic symbols are present in the generated executable
# RUN: yaml2obj -format=elf %s > %t-o.o
# RUN: lld -flavor gnu -target arm-linux-gnu \
# RUN: -Bstatic --noinhibit-exec %t-o.o -o %t
# RUN: llvm-readobj -symbols %t | FileCheck -check-prefix=STATIC %s
# STATIC-NOT: Name: _GLOBAL_OFFSET_TABLE_
# STATIC-NOT: Name: _DYNAMIC
# RUN: yaml2obj -format=elf %s > %t-o.o
# RUN: lld -flavor gnu -target arm-linux-gnu \
# RUN: --noinhibit-exec %t-o.o -o %t
# RUN: llvm-readobj -symbols %t | FileCheck -check-prefix=EXEC-DYN %s
# EXEC-DYN: Name: _GLOBAL_OFFSET_TABLE_
# EXEC-DYN-NEXT: Value: {{[0-9]+}}
# EXEC-DYN-NEXT: Size: 0
# EXEC-DYN-NEXT: Binding: Global (0x1)
# EXEC-DYN-NEXT: Type: Object (0x1)
# EXEC-DYN-NEXT: Other: 0
# EXEC-DYN-NEXT: Section: Absolute (0xFFF1)
# EXEC-DYN: Name: _DYNAMIC
# EXEC-DYN-NEXT: Value: {{[0-9]+}}
# EXEC-DYN-NEXT: Size: 0
# EXEC-DYN-NEXT: Binding: Global (0x1)
# EXEC-DYN-NEXT: Type: Object (0x1)
# EXEC-DYN-NEXT: Other: 0
# EXEC-DYN-NEXT: Section: Absolute (0xFFF1)
---
FileHeader:
Class: ELFCLASS32
Data: ELFDATA2LSB
Type: ET_REL
Machine: EM_ARM
Flags: [ EF_ARM_EABI_VER5 ]
Sections:
- Name: .text
Type: SHT_PROGBITS
Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
AddressAlign: 0x0000000000000004
Content: 04B02DE500B08DE20030A0E30300A0E100D04BE204B09DE41EFF2FE1
- Name: .data
Type: SHT_PROGBITS
Flags: [ SHF_WRITE, SHF_ALLOC ]
AddressAlign: 0x0000000000000001
Content: ''
- Name: .bss
Type: SHT_NOBITS
Flags: [ SHF_WRITE, SHF_ALLOC ]
AddressAlign: 0x0000000000000001
Content: ''
Symbols:
Global:
- Name: main
Type: STT_FUNC
Section: .text
...