[clang] [Clang] Link libgcc_s.1.dylib when building for macOS 10.5 and older (PR #141401)

[via cfe-commits]

https://github.com/Un1q32 updated https://github.com/llvm/llvm-project/pull/141401

>From 3cf20444591e70a8a6d8782048ca4f6c0e211112 Mon Sep 17 00:00:00 2001
From: Un1q32 <joey.t.reinhart at gmail.com>
Date: Mon, 27 Jan 2025 18:00:34 -0500
Subject: [PATCH 1/2] [Clang] Link libgcc_s.1.dylib when building for macOS
 10.5 and older (intel)

---
 clang/lib/Driver/ToolChains/Darwin.cpp | 17 +++++++++--------
 clang/test/Driver/darwin-ld.c          | 11 ++++++++++-
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index 452820159435f..ddc066d3d18a3 100644
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -1645,14 +1645,15 @@ void DarwinClang::AddLinkRuntimeLibArgs(const ArgList &Args,
     CmdArgs.push_back("-lSystem");
 
   // Select the dynamic runtime library and the target specific static library.
-  if (isTargetIOSBased()) {
-    // If we are compiling as iOS / simulator, don't attempt to link libgcc_s.1,
-    // it never went into the SDK.
-    // Linking against libgcc_s.1 isn't needed for iOS 5.0+
-    if (isIPhoneOSVersionLT(5, 0) && !isTargetIOSSimulator() &&
-        getTriple().getArch() != llvm::Triple::aarch64)
-      CmdArgs.push_back("-lgcc_s.1");
-  }
+  // If we are compiling as iOS / simulator, don't attempt to link libgcc_s.1,
+  // it never went into the SDK.
+  // Linking against libgcc_s.1 isn't needed for iOS 5.0+ or macOS 10.6+
+  if (isTargetIOSBased() && isIPhoneOSVersionLT(5, 0) &&
+      !isTargetIOSSimulator() && getTriple().getArch() != llvm::Triple::aarch64)
+    CmdArgs.push_back("-lgcc_s.1");
+  else if (isTargetMacOSBased() && isMacosxVersionLT(10, 6) &&
+           getTriple().getArch() != llvm::Triple::aarch64)
+    CmdArgs.push_back("-lgcc_s.1");
   AddLinkRuntimeLib(Args, CmdArgs, "builtins");
 }
 
diff --git a/clang/test/Driver/darwin-ld.c b/clang/test/Driver/darwin-ld.c
index f0ca411430cc7..9a8d98cdb9c2c 100644
--- a/clang/test/Driver/darwin-ld.c
+++ b/clang/test/Driver/darwin-ld.c
@@ -240,6 +240,15 @@
 // RUN: FileCheck -check-prefix=LINK_NO_IOS_ARM64_LIBGCC_S %s < %t.log
 // LINK_NO_IOS_ARM64_LIBGCC_S-NOT: lgcc_s.1
 
+// Check that clang links with libgcc_s.1 for Mac OS X 10.5 and earlier, but not arm64
+// RUN: %clang -target x86_64-apple-macosx10.5 -mmacosx-version-min=10.5 -### %t.o 2> %t.log
+// RUN: FileCheck -check-prefix=LINK_OSX_LIBGCC_S %s < %t.log
+// LINK_OSX_LIBGCC_S: lgcc_s.1
+
+// RUN: %clang -target arm64-apple-macosx10.5 -mmacosx-version-min=10.5 -### %t.o 2> %t.log
+// RUN: FileCheck -check-prefix=LINK_NO_OSX_ARM64_LIBGCC_S %s < %t.log
+// LINK_NO_OSX_ARM64_LIBGCC_S-NOT: lgcc_s.1
+
 // RUN: %clang -target x86_64-apple-darwin12 -rdynamic -### %t.o \
 // RUN:   -fuse-ld= -mlinker-version=100 2> %t.log
 // RUN: FileCheck -check-prefix=LINK_NO_EXPORT_DYNAMIC %s < %t.log
@@ -385,4 +394,4 @@
 // RUN:   %clang -target armv7em-apple-darwin -mno-outline -### %t.o 2> %t.log
 // RUN: FileCheck -check-prefix=ARMV7EM-MNO_OUTLINE %s < %t.log
 // ARMV7EM-MNO_OUTLINE: {{ld(.exe)?"}}
-// ARMV7EM-MNO_OUTLINE-SAME: "-mllvm" "-enable-machine-outliner=never" "-mllvm" "-enable-linkonceodr-outlining"
\ No newline at end of file
+// ARMV7EM-MNO_OUTLINE-SAME: "-mllvm" "-enable-machine-outliner=never" "-mllvm" "-enable-linkonceodr-outlining"

>From c82c7704c306f3d86b5226b137521bf7bf98a3cd Mon Sep 17 00:00:00 2001
From: Un1q32 <joey.t.reinhart at gmail.com>
Date: Wed, 4 Jun 2025 00:05:56 -0400
Subject: [PATCH 2/2] change the order of the if statmenets to check aarch64
 first

---
 clang/lib/Driver/ToolChains/Darwin.cpp | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index ddc066d3d18a3..516082192a0c9 100644
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -1648,12 +1648,13 @@ void DarwinClang::AddLinkRuntimeLibArgs(const ArgList &Args,
   // If we are compiling as iOS / simulator, don't attempt to link libgcc_s.1,
   // it never went into the SDK.
   // Linking against libgcc_s.1 isn't needed for iOS 5.0+ or macOS 10.6+
-  if (isTargetIOSBased() && isIPhoneOSVersionLT(5, 0) &&
-      !isTargetIOSSimulator() && getTriple().getArch() != llvm::Triple::aarch64)
-    CmdArgs.push_back("-lgcc_s.1");
-  else if (isTargetMacOSBased() && isMacosxVersionLT(10, 6) &&
-           getTriple().getArch() != llvm::Triple::aarch64)
-    CmdArgs.push_back("-lgcc_s.1");
+  if (getTriple().getArch() != llvm::Triple::aarch64) {
+    if (isTargetIOSBased() && isIPhoneOSVersionLT(5, 0) &&
+        !isTargetIOSSimulator())
+      CmdArgs.push_back("-lgcc_s.1");
+    else if (isTargetMacOSBased() && isMacosxVersionLT(10, 6))
+      CmdArgs.push_back("-lgcc_s.1");
+  }
   AddLinkRuntimeLib(Args, CmdArgs, "builtins");
 }