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[lld-macho] Dylib symbols should always replace undefined symbols 

Summary:
Otherwise we get undefined symbol errors depending on the order of
arguments on the command line.

Depends on D78270.

Reviewers: ruiu, pcc, MaskRay, smeenai, alexshap, gkm, Ktwu, christylee

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79114
This commit is contained in:
Jez Ng 2020-04-29 05:30:47 -07:00
parent b3e2fc931d
commit 5d3feefa0d
2 changed files with 45 additions and 1 deletions
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2
lld/MachO/SymbolTable.cpp
View File

@ -64,7 +64,7 @@ Symbol *SymbolTable::addDylib(StringRef name, DylibFile *file) {
bool wasInserted;
std::tie(s, wasInserted) = insert(name);
if (wasInserted)
if (wasInserted || isa<Undefined>(s))
replaceSymbol<DylibSymbol>(s, file, name);
return s;
}

44
lld/test/MachO/resolution.s Normal file
View File

@ -0,0 +1,44 @@
# REQUIRES: x86
# RUN: mkdir -p %t
# RUN: echo '.globl _foo, _bar, _baz; _foo: _bar: _baz:' | \
# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin -o %t/libresolution.o
# RUN: lld -flavor darwinnew -dylib -install_name \
# RUN: @executable_path/libresolution.dylib %t/libresolution.o -o %t/libresolution.dylib
# RUN: lld -flavor darwinnew -dylib -install_name \
# RUN: @executable_path/libresolution2.dylib %t/libresolution.o -o %t/libresolution2.dylib
# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t/resolution.o
## Check that we select the symbol defined in the first dylib passed on the
## command line.
# RUN: lld -flavor darwinnew -o %t/dylib-first -Z -L%t -lresolution -lresolution2 %t/resolution.o
# RUN: llvm-objdump --macho --bind %t/dylib-first | FileCheck %s --check-prefix=DYLIB-FIRST
# DYLIB-FIRST: libresolution _foo
# RUN: lld -flavor darwinnew -o %t/dylib2-first -Z -L%t -lresolution2 -lresolution %t/resolution.o
# RUN: llvm-objdump --macho --bind %t/dylib2-first | FileCheck %s --check-prefix=DYLIB2-FIRST
# DYLIB2-FIRST: libresolution2 _foo
## Also check that defined symbols take precedence over dylib symbols.
# DYLIB-FIRST-NOT: libresolution _bar
# DYLIB-FIRST-NOT: libresolution _baz
## Check that we pick the dylib symbol over the undefined symbol in the object
## file, even if the object file appears first on the command line.
# RUN: lld -flavor darwinnew -o %t/obj-first -Z -L%t %t/resolution.o -lresolution
# RUN: llvm-objdump --macho --bind %t/obj-first | FileCheck %s --check-prefix=OBJ-FIRST
# OBJ-FIRST: libresolution _foo
## But defined symbols should still take precedence.
# OBJ-FIRST-NOT: libresolution _bar
# OBJ-FIRST-NOT: libresolution _baz
.globl _main, _bar
# Global defined symbol
_bar:
# Local defined symbol
_baz:
_main:
movq _foo@GOTPCREL(%rip), %rsi
movq _bar@GOTPCREL(%rip), %rsi
movq _baz@GOTPCREL(%rip), %rsi
ret