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[lld/mac] When handling @loader_path, use realpath() of symlinks 

This is important for Frameworks, which are usually symlinks.

ld64 gets this right for @rpath that's replaced with @loader_path, but not for
bare @loader_path -- ld64's code calls realpath() in that case too, but ignores
the result.

ld64 somehow manages to find libbar1.dylib in the test without the
explicit `-rpath` in Foo1. I don't understand why or how. But this
change is a step forward and fixes an immediate problem I'm having,
so let's start with this :)

Differential Revision: https://reviews.llvm.org/D103990
This commit is contained in:
Nico Weber 2021-06-09 16:09:44 -04:00
parent cf11d9585a
commit 0e399eb527
2 changed files with 65 additions and 4 deletions
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12
lld/MachO/InputFiles.cpp
View File

@ -788,16 +788,20 @@ static DylibFile *findDylib(StringRef path, DylibFile *umbrella,
path.consume_front("@executable_path/")) {
// ld64 allows overriding this with the undocumented flag -executable_path.
// lld doesn't currently implement that flag.
path::append(newPath, sys::path::parent_path(config->outputFile), path);
path::append(newPath, path::parent_path(config->outputFile), path);
path = newPath;
} else if (path.consume_front("@loader_path/")) {
path::append(newPath, sys::path::parent_path(umbrella->getName()), path);
fs::real_path(umbrella->getName(), newPath);
path::remove_filename(newPath);
path::append(newPath, path);
path = newPath;
} else if (path.startswith("@rpath/")) {
for (StringRef rpath : umbrella->rpaths) {
newPath.clear();
if (rpath.consume_front("@loader_path/"))
path::append(newPath, sys::path::parent_path(umbrella->getName()));
if (rpath.consume_front("@loader_path/")) {
fs::real_path(umbrella->getName(), newPath);
path::remove_filename(newPath);
}
path::append(newPath, rpath, path.drop_front(strlen("@rpath/")));
if (Optional<std::string> dylibPath = resolveDylibPath(newPath))
return loadDylib(*dylibPath, umbrella);

57
lld/test/MachO/link-search-at-loader-path-symlink.s Normal file
View File

@ -0,0 +1,57 @@
# REQUIRES: x86, shell
# RUN: rm -rf %t; split-file %s %t
# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/foo.s -o %t/foo.o
# RUN: llvm-mc -filetype obj -triple x86_64-apple-darwin %t/bar.s -o %t/bar.o
# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/test.s -o %t/test.o
## 1. Test symlink with reexport to @rpath and rpath pointing to @loader_path.
## The @loader_path-relative path is looked after resolving the symlink.
# RUN: mkdir -p %t/Foo1.framework/Versions/A
# RUN: %lld -dylib -install_name @rpath/libbar1.dylib %t/bar.o -o %t/Foo1.framework/Versions/A/libbar1.dylib
# RUN: %lld -dylib -install_name %t/Foo1.framework/Versions/A/Foo1 %t/foo.o \
# RUN: -reexport_library %t/Foo1.framework/Versions/A/libbar1.dylib \
# RUN: -rpath @loader_path/. \
# RUN: -o %t/Foo1.framework/Versions/A/Foo1
# RUN: ln -sf A %t/Foo1.framework/Versions/Current
# RUN: ln -sf Versions/Current/Foo1 %t/Foo1.framework/Foo1
# RUN: %lld -lSystem -F%t -framework Foo1 %t/test.o -o %t/test1
## 2. Test symlink with reexport to @loader_path-relative path directly.
## The @loader_path-relative path is looked after resolving the symlink.
## ld64 gets this wrong -- it calls realpath() but ignores the result.
## (ld64-609, Options.cpp, Options::findFile(), "@loader_path/" handling.)
# RUN: mkdir -p %t/Foo2.framework/Versions/A
# RUN: %lld -dylib -install_name @loader_path/libbar2.dylib %t/bar.o -o %t/Foo2.framework/Versions/A/libbar2.dylib
# RUN: %lld -dylib -install_name %t/Foo2.framework/Versions/A/Foo2 %t/foo.o \
# RUN: -reexport_library %t/Foo2.framework/Versions/A/libbar2.dylib \
# RUN: -o %t/Foo2.framework/Versions/A/Foo2
# RUN: ln -sf A %t/Foo2.framework/Versions/Current
# RUN: ln -sf Versions/Current/Foo2 %t/Foo2.framework/Foo2
# RUN: %lld -lSystem -F%t -framework Foo2 %t/test.o -o %t/test2
#--- foo.s
.globl _foo
_foo:
ret
#--- bar.s
.globl _bar
_bar:
ret
#--- test.s
.globl _main
.text
_main:
callq _foo
callq _bar
ret