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

[Leonard Grey via llvm-commits]

https://github.com/speednoisemovement updated https://github.com/llvm/llvm-project/pull/132275

>From 398bcfa1599b4850b188485952dd86bc630fa72d Mon Sep 17 00:00:00 2001
From: Leonard Grey <lgrey at chromium.org>
Date: Thu, 20 Mar 2025 15:32:07 -0400
Subject: [PATCH 1/2] [lld-macho] Don't double emit reexported libraries

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>>
---
 lld/MachO/Writer.cpp         | 20 +++++++++++---------
 lld/test/MachO/sub-library.s | 11 +++++++++++
 2 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/lld/MachO/Writer.cpp b/lld/MachO/Writer.cpp
index d9856a46e8cb8..7a5fdcd2276a5 100644
--- a/lld/MachO/Writer.cpp
+++ b/lld/MachO/Writer.cpp
@@ -938,17 +938,19 @@ 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));
+                                        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
 

>From e51bd5ec78d73a54e250a1a95ed3fd8acd83cea5 Mon Sep 17 00:00:00 2001
From: Leonard Grey <lgrey at chromium.org>
Date: Thu, 20 Mar 2025 15:48:42 -0400
Subject: [PATCH 2/2] Format

---
 lld/MachO/Writer.cpp | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/lld/MachO/Writer.cpp b/lld/MachO/Writer.cpp
index 7a5fdcd2276a5..f312828819dcc 100644
--- a/lld/MachO/Writer.cpp
+++ b/lld/MachO/Writer.cpp
@@ -941,16 +941,17 @@ template <class LP> void Writer::createLoadCommands() {
     LoadCommandType lcType = LC_LOAD_DYLIB;
     if (dylibFile->reexport) {
       if (dylibFile->forceWeakImport)
-        warn(path::filename(dylibFile->getName()) + " is re-exported so cannot be weak-linked");
+        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) {
+    } 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));
-
+                                            dylibFile->compatibilityVersion,
+                                            dylibFile->currentVersion));
   }
 
   for (const auto &dyldEnv : config->dyldEnvs)