From 2129cc1b3a14df5c24e5b2a680f18b88d5af4142 Mon Sep 17 00:00:00 2001
From: Keith Smiley <keithbsmiley@gmail.com>
Date: Wed, 31 May 2023 18:55:17 -0700
Subject: [PATCH] [clang][Darwin] Error out when missing requested libarclite
 library

Starting with the SDKs provided with Xcode 14.3, this library no longer
exists. Before this change this results in an opaque linker error in the
case that your deployment target is low enough that this library is
added. This produces a more useful error message in that case.

Differential Revision: https://reviews.llvm.org/D150988
---
 clang/include/clang/Basic/DiagnosticDriverKinds.td  | 3 +++
 clang/lib/Driver/ToolChains/Darwin.cpp              | 3 +++
 clang/test/Driver/arclite-link-external-toolchain.c | 3 +++
 clang/test/Driver/arclite-link.c                    | 6 +++++-
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td
index d56708e..d7e5987 100644
--- a/clang/include/clang/Basic/DiagnosticDriverKinds.td
+++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td
@@ -619,6 +619,9 @@ def warn_drv_darwin_sdk_invalid_settings : Warning<
   "SDK settings were ignored as 'SDKSettings.json' could not be parsed">,
   InGroup<DiagGroup<"darwin-sdk-settings">>;
 
+def err_drv_darwin_sdk_missing_arclite : Error<
+  "SDK does not contain 'libarclite' at the path '%0'; try increasing the minimum deployment target">;
+
 def err_drv_trivial_auto_var_init_stop_after_missing_dependency : Error<
   "'-ftrivial-auto-var-init-stop-after=*' is used without "
   "'-ftrivial-auto-var-init=zero' or '-ftrivial-auto-var-init=pattern'">;
diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index 123057a..922eb8a 100644
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -1221,6 +1221,9 @@ void DarwinClang::AddLinkARCArgs(const ArgList &Args,
     P += "macosx";
   P += ".a";
 
+  if (!getVFS().exists(P))
+    getDriver().Diag(clang::diag::err_drv_darwin_sdk_missing_arclite) << P;
+
   CmdArgs.push_back(Args.MakeArgString(P));
 }
 
diff --git a/clang/test/Driver/arclite-link-external-toolchain.c b/clang/test/Driver/arclite-link-external-toolchain.c
index cc62cd1..8391a85 100644
--- a/clang/test/Driver/arclite-link-external-toolchain.c
+++ b/clang/test/Driver/arclite-link-external-toolchain.c
@@ -4,5 +4,8 @@
 // RUN:   -isysroot %t.tmpdir/Xcode.app/Contents/Developers/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk \
 // RUN:   %s 2>&1 | FileCheck %s
 
+// CHECK: error: SDK does not contain 'libarclite' at the path '
+// CHECK: .tmpdir/Xcode.app/{{.*}}libarclite_macosx.a';
+// CHECK: try increasing the minimum deployment target
 // CHECK: -lfoo
 // CHECK: .tmpdir/Xcode.app/{{.*}}libarclite_macosx.a
diff --git a/clang/test/Driver/arclite-link.c b/clang/test/Driver/arclite-link.c
index e8cee3e..595ca0b 100644
--- a/clang/test/Driver/arclite-link.c
+++ b/clang/test/Driver/arclite-link.c
@@ -1,9 +1,13 @@
 // RUN: touch %t.o
-// RUN: %clang -### -target x86_64-apple-darwin10 -fobjc-link-runtime -lfoo -mmacosx-version-min=10.10 %t.o 2>&1 | FileCheck -check-prefix=CHECK-ARCLITE-OSX %s
+// RUN: mkdir -p %t.tmpdir/Xcode.app/Contents/Developers/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk
+// RUN: %clang -### -target x86_64-apple-darwin10 -fobjc-link-runtime -lfoo -mmacosx-version-min=10.10 %t.o \
+// RUN: -isysroot %t.tmpdir/Xcode.app/Contents/Developers/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk 2>&1 | FileCheck -check-prefix=CHECK-ARCLITE-OSX %s
 // RUN: %clang -### -target x86_64-apple-darwin10 -fobjc-link-runtime -mmacosx-version-min=10.11 %t.o 2>&1 | FileCheck -check-prefix=CHECK-NOARCLITE %s
 // RUN: %clang -### -target i386-apple-darwin10 -fobjc-link-runtime -mmacosx-version-min=10.7 %t.o 2>&1 | FileCheck -check-prefix=CHECK-NOARCLITE %s
 // RUN: %clang -### -target x86_64-apple-darwin10 -fobjc-link-runtime -nostdlib %t.o 2>&1 | FileCheck -check-prefix=CHECK-NOSTDLIB %s
 
+// CHECK-ARCLITE-OSX: .tmpdir/Xcode.app/{{.*}}libarclite_macosx.a';
+// CHECK-ARCLITE-OSX: try increasing the minimum deployment target
 // CHECK-ARCLITE-OSX: -lfoo
 // CHECK-ARCLITE-OSX: libarclite_macosx.a
 // CHECK-ARCLITE-OSX: -framework
-- 
2.7.4