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[mach-o] Support old style objc class names in export lists 

Objective-C switched to a new ABI which uses a different mangling for class
names.  But to keep projects building that use export lists that use the old
class name mangling, the linker recognizes the old names and transforms them
to the new mangling.

llvm-svn: 220598
This commit is contained in:
Nick Kledzik 2014-10-24 22:28:54 +00:00
parent 761d6549bc
commit 4183dbcc03
2 changed files with 83 additions and 0 deletions
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20
lld/lib/ReaderWriter/MachO/MachOLinkingContext.cpp
View File

@ -715,6 +715,26 @@ bool MachOLinkingContext::sectionAligned(StringRef seg, StringRef sect,
void MachOLinkingContext::addExportSymbol(StringRef sym) {
// Support old crufty export lists with bogus entries.
if (sym.endswith(".eh") || sym.startswith(".objc_category_name_")) {
llvm::errs() << "warning: ignoring " << sym << " in export list\n";
return;
}
// Only i386 MacOSX uses old ABI, so don't change those.
if ((_os != OS::macOSX) || (_arch != arch_x86)) {
// ObjC has two differnent ABIs. Be nice and allow one export list work for
// both ABIs by renaming symbols.
if (sym.startswith(".objc_class_name_")) {
std::string abi2className("_OBJC_CLASS_$_");
abi2className += sym.substr(17);
_exportedSymbols.insert(copy(abi2className));
std::string abi2metaclassName("_OBJC_METACLASS_$_");
abi2metaclassName += sym.substr(17);
_exportedSymbols.insert(copy(abi2metaclassName));
return;
}
}
// FIXME: Support wildcards.
_exportedSymbols.insert(sym);
}

63
lld/test/mach-o/objc_export_list.yaml Normal file
View File

@ -0,0 +1,63 @@
# RUN: lld -flavor darwin -arch x86_64 -dylib %s -o %t \
# RUN: -exported_symbol .objc_class_name_Foo %p/Inputs/libSystem.yaml
# RUN: llvm-nm -m %t | FileCheck %s
#
# Test that exported objc classes can be specificed using old naming
# (.e.g .objc_class_name_Foo instead of _OBJC_CLASS_$_Foo)
#
--- !mach-o
arch: x86_64
file-type: MH_OBJECT
flags: [ MH_SUBSECTIONS_VIA_SYMBOLS ]
sections:
- segment: __DATA
section: __objc_data
type: S_REGULAR
attributes: [ ]
alignment: 3
address: 0x0000000000000000
content: [ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ]
relocations:
- offset: 0x00000030
type: X86_64_RELOC_UNSIGNED
length: 3
pc-rel: false
extern: true
symbol: 0
- offset: 0x00000028
type: X86_64_RELOC_UNSIGNED
length: 3
pc-rel: false
extern: true
symbol: 1
- offset: 0x00000000
type: X86_64_RELOC_UNSIGNED
length: 3
pc-rel: false
extern: true
symbol: 1
global-symbols:
- name: '_OBJC_CLASS_$_Foo'
type: N_SECT
scope: [ N_EXT ]
sect: 1
value: 0x0000000000000000
- name: '_OBJC_METACLASS_$_Foo'
type: N_SECT
scope: [ N_EXT ]
sect: 1
value: 0x0000000000000028
...
# CHECK: (__DATA,__objc_data) external _OBJC_CLASS_$_Foo
# CHECK: (__DATA,__objc_data) external _OBJC_METACLASS_$_Foo