[lld] e385ec9 - [lld-macho] Don't double emit reexported libraries (#132275)

[via llvm-commits]

Author: Leonard Grey
Date: 2025-03-21T09:31:46-04:00
New Revision: e385ec90e2cbc6398cc6f445d995cf875bbc15b2

URL: https://github.com/llvm/llvm-project/commit/e385ec90e2cbc6398cc6f445d995cf875bbc15b2
DIFF: https://github.com/llvm/llvm-project/commit/e385ec90e2cbc6398cc6f445d995cf875bbc15b2.diff

LOG: [lld-macho] Don't double emit reexported libraries (#132275)

When a library is specified with both `-l` and `-reexport_libraries`,
lld will emit two load commands for it, in contrast with ld64.
In an upcoming version of macOS, this fails dyld validation; see
https://crbug.com/404905688

---------

Co-authored-by: Mark Rowe <markrowe at chromium.org>>

Added: 
    

Modified: 
    lld/MachO/Writer.cpp
    lld/test/MachO/sub-library.s

Removed: 
    


################################################################################
diff  --git a/lld/MachO/Writer.cpp b/lld/MachO/Writer.cpp
index d9856a46e8cb8..f312828819dcc 100644
--- a/lld/MachO/Writer.cpp
+++ b/lld/MachO/Writer.cpp
@@ -938,17 +938,20 @@ template <class LP> void Writer::createLoadCommands() {
     }
 
     ordinal = dylibFile->ordinal = dylibOrdinal++;
-    LoadCommandType lcType =
-        dylibFile->forceWeakImport || dylibFile->refState == RefState::Weak
-            ? LC_LOAD_WEAK_DYLIB
-            : LC_LOAD_DYLIB;
+    LoadCommandType lcType = LC_LOAD_DYLIB;
+    if (dylibFile->reexport) {
+      if (dylibFile->forceWeakImport)
+        warn(path::filename(dylibFile->getName()) +
+             " is re-exported so cannot be weak-linked");
+
+      lcType = LC_REEXPORT_DYLIB;
+    } else if (dylibFile->forceWeakImport ||
+               dylibFile->refState == RefState::Weak) {
+      lcType = LC_LOAD_WEAK_DYLIB;
+    }
     in.header->addLoadCommand(make<LCDylib>(lcType, dylibFile->installName,
                                             dylibFile->compatibilityVersion,
                                             dylibFile->currentVersion));
-
-    if (dylibFile->reexport)
-      in.header->addLoadCommand(
-          make<LCDylib>(LC_REEXPORT_DYLIB, dylibFile->installName));
   }
 
   for (const auto &dyldEnv : config->dyldEnvs)

diff  --git a/lld/test/MachO/sub-library.s b/lld/test/MachO/sub-library.s
index ed0a96aa58f90..d799b8d54c01a 100644
--- a/lld/test/MachO/sub-library.s
+++ b/lld/test/MachO/sub-library.s
@@ -42,6 +42,17 @@
 # REEXPORT-HEADERS-NOT: Load command
 # REEXPORT-HEADERS:     name    [[PATH]]
 
+## Check that specifying a library both with `l` and `reexport_library`
+## doesn't emit two load commands.
+# RUN: %lld -dylib -reexport_library %t/libgoodbye.dylib \
+# RUN:   -L%t -lgoodbye %t/libsuper.o -o %t/libsuper.dylib
+# RUN: llvm-otool -L %t/libsuper.dylib | FileCheck %s \
+# RUN:   --check-prefix=REEXPORT-DOUBLE -DPATH=%t/libgoodbye.dylib
+
+# REEXPORT-DOUBLE: [[PATH]]
+# REEXPORT-DOUBLE-SAME: reexport
+# REEXPORT-DOUBLE-NOT: [[PATH]]
+
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t/sub-library.o
 # RUN: %lld -o %t/sub-library -L%t -lsuper %t/sub-library.o