[clang] Revert "[Fix] Disable fdefine-target-os-macros for now" (PR #78353)

[Zixu Wang via cfe-commits]

https://github.com/zixu-w created https://github.com/llvm/llvm-project/pull/78353

https://github.com/llvm/llvm-test-suite/pull/65 fixed the llvm-test-suite errors. Reapply the change to enable `fdefine-target-os-macros` by default for Darwin targets.

This reverts commit 63be986f612c175559efffed9daebcb944fa5cea.

>From 925a7eb15d04bb64adff3663244aad4b7b05f3d6 Mon Sep 17 00:00:00 2001
From: Zixu Wang <zixu_wang at apple.com>
Date: Thu, 14 Dec 2023 15:44:06 -0800
Subject: [PATCH] Revert "[Fix] Disable fdefine-target-os-macros for now"

Reapply the change to enable `fdefine-target-os-macros` by default for
Darwin targets.

This reverts commit 63be986f612c175559efffed9daebcb944fa5cea.
---
 clang/lib/Driver/ToolChains/Darwin.cpp       |  4 +++
 clang/test/Driver/fdefine-target-os-macros.c | 29 +++++++-------------
 2 files changed, 14 insertions(+), 19 deletions(-)

diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index 65846cace461e3..8f24e5287e198c 100644
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -2917,6 +2917,10 @@ void Darwin::addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
   // to fix the same problem with C++ headers, and is generally fragile.
   if (!sdkSupportsBuiltinModules(TargetPlatform, SDKInfo))
     CC1Args.push_back("-fbuiltin-headers-in-system-modules");
+
+  if (!DriverArgs.hasArgNoClaim(options::OPT_fdefine_target_os_macros,
+                                options::OPT_fno_define_target_os_macros))
+    CC1Args.push_back("-fdefine-target-os-macros");
 }
 
 void Darwin::addClangCC1ASTargetOptions(
diff --git a/clang/test/Driver/fdefine-target-os-macros.c b/clang/test/Driver/fdefine-target-os-macros.c
index 030d4ce34cb282..d7379dd3d5396b 100644
--- a/clang/test/Driver/fdefine-target-os-macros.c
+++ b/clang/test/Driver/fdefine-target-os-macros.c
@@ -1,12 +1,11 @@
 // RUN: %clang -### --target=arm64-apple-darwin %s 2>&1 | FileCheck %s --check-prefix=DARWIN-DEFAULT
-// DARWIN-DEFAULT-NOT: "-fdefine-target-os-macros"
+// DARWIN-DEFAULT: "-fdefine-target-os-macros"
 
 // RUN: %clang -### --target=arm-none-linux-gnu %s 2>&1 | FileCheck %s --check-prefix=NON-DARWIN-DEFAULT
 // RUN: %clang -### --target=x86_64-pc-win32 %s 2>&1 | FileCheck %s --check-prefix=NON-DARWIN-DEFAULT
 // NON-DARWIN-DEFAULT-NOT: "-fdefine-target-os-macros"
 
-// RUN: %clang -dM -E --target=arm64-apple-macos \
-// RUN:        -fdefine-target-os-macros %s 2>&1 \
+// RUN: %clang -dM -E --target=arm64-apple-macos %s 2>&1 \
 // RUN: | FileCheck %s -DMAC=1         \
 // RUN:                -DOSX=1         \
 // RUN:                -DIPHONE=0      \
@@ -21,8 +20,7 @@
 // RUN:                -DLINUX=0       \
 // RUN:                -DUNIX=0
 
-// RUN: %clang -dM -E --target=arm64-apple-ios \
-// RUN:        -fdefine-target-os-macros %s 2>&1 \
+// RUN: %clang -dM -E --target=arm64-apple-ios %s 2>&1 \
 // RUN: | FileCheck %s -DMAC=1         \
 // RUN:                -DOSX=0         \
 // RUN:                -DIPHONE=1      \
@@ -37,8 +35,7 @@
 // RUN:                -DLINUX=0       \
 // RUN:                -DUNIX=0
 
-// RUN: %clang -dM -E --target=arm64-apple-ios-macabi \
-// RUN:        -fdefine-target-os-macros %s 2>&1 \
+// RUN: %clang -dM -E --target=arm64-apple-ios-macabi %s 2>&1 \
 // RUN: | FileCheck %s -DMAC=1         \
 // RUN:                -DOSX=0         \
 // RUN:                -DIPHONE=1      \
@@ -53,8 +50,7 @@
 // RUN:                -DLINUX=0       \
 // RUN:                -DUNIX=0
 
-// RUN: %clang -dM -E --target=arm64-apple-ios-simulator \
-// RUN:        -fdefine-target-os-macros %s 2>&1 \
+// RUN: %clang -dM -E --target=arm64-apple-ios-simulator %s 2>&1 \
 // RUN: | FileCheck %s -DMAC=1         \
 // RUN:                -DOSX=0         \
 // RUN:                -DIPHONE=1      \
@@ -69,8 +65,7 @@
 // RUN:                -DLINUX=0       \
 // RUN:                -DUNIX=0
 
-// RUN: %clang -dM -E --target=arm64-apple-tvos \
-// RUN:        -fdefine-target-os-macros %s 2>&1 \
+// RUN: %clang -dM -E --target=arm64-apple-tvos %s 2>&1 \
 // RUN: | FileCheck %s -DMAC=1         \
 // RUN:                -DOSX=0         \
 // RUN:                -DIPHONE=1      \
@@ -85,8 +80,7 @@
 // RUN:                -DLINUX=0       \
 // RUN:                -DUNIX=0
 
-// RUN: %clang -dM -E --target=arm64-apple-tvos-simulator \
-// RUN:        -fdefine-target-os-macros %s 2>&1 \
+// RUN: %clang -dM -E --target=arm64-apple-tvos-simulator %s 2>&1 \
 // RUN: | FileCheck %s -DMAC=1         \
 // RUN:                -DOSX=0         \
 // RUN:                -DIPHONE=1      \
@@ -101,8 +95,7 @@
 // RUN:                -DLINUX=0       \
 // RUN:                -DUNIX=0
 
-// RUN: %clang -dM -E --target=arm64-apple-watchos \
-// RUN:        -fdefine-target-os-macros %s 2>&1 \
+// RUN: %clang -dM -E --target=arm64-apple-watchos %s 2>&1 \
 // RUN: | FileCheck %s -DMAC=1         \
 // RUN:                -DOSX=0         \
 // RUN:                -DIPHONE=1      \
@@ -117,8 +110,7 @@
 // RUN:                -DLINUX=0       \
 // RUN:                -DUNIX=0
 
-// RUN: %clang -dM -E --target=arm64-apple-watchos-simulator \
-// RUN:        -fdefine-target-os-macros %s 2>&1 \
+// RUN: %clang -dM -E --target=arm64-apple-watchos-simulator %s 2>&1 \
 // RUN: | FileCheck %s -DMAC=1         \
 // RUN:                -DOSX=0         \
 // RUN:                -DIPHONE=1      \
@@ -133,8 +125,7 @@
 // RUN:                -DLINUX=0       \
 // RUN:                -DUNIX=0
 
-// RUN: %clang -dM -E --target=arm64-apple-driverkit \
-// RUN:        -fdefine-target-os-macros %s 2>&1 \
+// RUN: %clang -dM -E --target=arm64-apple-driverkit %s 2>&1 \
 // RUN: | FileCheck %s -DMAC=1         \
 // RUN:                -DOSX=0         \
 // RUN:                -DIPHONE=0      \