[lld] 5248902 - [lld/mac] Implement support for searching dylibs with @loader_path/ in install name

[Nico Weber via llvm-commits]

Author: Nico Weber
Date: 2021-06-06T20:19:50-04:00
New Revision: 52489021cf8ba7bb3b8e5ae56ab5f25ce4790c0f

URL: https://github.com/llvm/llvm-project/commit/52489021cf8ba7bb3b8e5ae56ab5f25ce4790c0f
DIFF: https://github.com/llvm/llvm-project/commit/52489021cf8ba7bb3b8e5ae56ab5f25ce4790c0f.diff

LOG: [lld/mac] Implement support for searching dylibs with @loader_path/ in install name

Differential Revision: https://reviews.llvm.org/D103779

Added: 
    lld/test/MachO/link-search-at-loader-path.s

Modified: 
    lld/MachO/InputFiles.cpp

Removed: 
    


################################################################################
diff  --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
index ac34920b1d76..2fe338f3489f 100644
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -752,15 +752,15 @@ static DylibFile *loadDylib(StringRef path, DylibFile *umbrella) {
 //
 // Re-exports can either refer to on-disk files, or to documents within .tbd
 // files.
-DylibFile *findDylib(StringRef path, DylibFile *umbrella,
-                     const InterfaceFile *currentTopLevelTapi) {
+static DylibFile *findDylib(StringRef path, DylibFile *umbrella,
+                            const InterfaceFile *currentTopLevelTapi) {
   if (path::is_absolute(path, path::Style::posix))
     for (StringRef root : config->systemLibraryRoots)
       if (Optional<std::string> dylibPath =
               resolveDylibPath((root + path).str()))
         return loadDylib(*dylibPath, umbrella);
 
-  // TODO: Expand @loader_path, @rpath etc, handle -dylib_file
+  // TODO: Expand @rpath, handle -dylib_file
   SmallString<128> newPath;
   if (config->outputType == MH_EXECUTE &&
       path.consume_front("@executable_path/")) {
@@ -768,6 +768,9 @@ DylibFile *findDylib(StringRef path, DylibFile *umbrella,
     // lld doesn't currently implement that flag.
     path::append(newPath, sys::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);
+    path = newPath;
   }
 
   if (currentTopLevelTapi) {
@@ -808,8 +811,8 @@ static bool isImplicitlyLinked(StringRef path) {
   return false;
 }
 
-void loadReexport(StringRef path, DylibFile *umbrella,
-                  const InterfaceFile *currentTopLevelTapi) {
+static void loadReexport(StringRef path, DylibFile *umbrella,
+                         const InterfaceFile *currentTopLevelTapi) {
   DylibFile *reexport = findDylib(path, umbrella, currentTopLevelTapi);
   if (!reexport)
     error("unable to locate re-export with install name " + path);

diff  --git a/lld/test/MachO/link-search-at-loader-path.s b/lld/test/MachO/link-search-at-loader-path.s
new file mode 100644
index 000000000000..96ed266fa91c
--- /dev/null
+++ b/lld/test/MachO/link-search-at-loader-path.s
@@ -0,0 +1,34 @@
+# REQUIRES: x86
+
+# RUN: rm -rf %t; split-file %s %t
+# RUN: mkdir %t/subdir
+
+# 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/main.s -o %t/main.o
+
+# RUN: %lld -dylib -install_name @loader_path/libfoo.dylib %t/foo.o -o %t/subdir/libfoo.dylib
+
+## Test that @loader_path is replaced by the actual path, not by install_name.
+# RUN: %lld -dylib -reexport_library %t/subdir/libfoo.dylib -install_name /tmp/libbar.dylib %t/bar.o -o %t/subdir/libbar.dylib
+
+# RUN: %lld -lSystem %t/main.o %t/subdir/libbar.dylib -o %t/test
+# RUN: %lld -dylib -lSystem %t/main.o %t/subdir/libbar.dylib -o %t/libtest.dylib
+
+#--- foo.s
+.globl _foo
+_foo:
+  retq
+
+#--- bar.s
+.globl _bar
+_bar:
+  retq
+
+#--- main.s
+.section __TEXT,__text
+.global _main
+_main:
+  callq _foo
+  callq _bar
+  ret