[clang] [test][Driver][clang] Fix darwin-embedded-search-paths.c when CLANG_DEFAULT_CXX_STDLIB is libc++ (PR #122145)

[Ian Anderson via cfe-commits]

https://github.com/ian-twilightcoder updated https://github.com/llvm/llvm-project/pull/122145

>From 4bd9ce309935451900d7ebc13a111bedf91d12d0 Mon Sep 17 00:00:00 2001
From: Ian Anderson <iana at apple.com>
Date: Wed, 8 Jan 2025 09:35:04 -0800
Subject: [PATCH] [test][Driver][clang] Fix darwin-embedded-search-paths.c when
 CLANG_DEFAULT_CXX_STDLIB is libc++

Split darwin-embedded-search-paths.c into two tests for the different values of CLANG_DEFAULT_CXX_STDLIB.
---
 .../darwin-embedded-search-paths-libcxx.c     | 45 +++++++++++++++++++
 .../Driver/darwin-embedded-search-paths.c     |  4 +-
 2 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 clang/test/Driver/darwin-embedded-search-paths-libcxx.c

diff --git a/clang/test/Driver/darwin-embedded-search-paths-libcxx.c b/clang/test/Driver/darwin-embedded-search-paths-libcxx.c
new file mode 100644
index 00000000000000..0f9a8467b061aa
--- /dev/null
+++ b/clang/test/Driver/darwin-embedded-search-paths-libcxx.c
@@ -0,0 +1,45 @@
+// REQUIRES: default-cxx-stdlib=libc++
+// UNSUPPORTED: system-windows
+//   Windows is unsupported because we use the Unix path separator `/` in the test.
+
+// Unlike the Darwin driver, the MachO driver doesn't add any framework search paths,
+// only the normal header ones.
+// RUN: %clang -x c -target arm64-apple-none-macho -isysroot %S/Inputs/MacOSX15.1.sdk -### -c %s 2>&1 \
+// RUN: | FileCheck --check-prefixes=CC1,NO-CXX,ULI,CI,UI,NO-FW -DSDKROOT=%S/Inputs/MacOSX15.1.sdk %s
+
+// Unlike the Darwin driver, the MachO driver doesn't default to libc++, but when
+// CLANG_DEFAULT_CXX_STDLIB is libc++ then the MachO driver should find the search path.
+// RUN: %clang -x c++ -target arm64-apple-none-macho -isysroot %S/Inputs/MacOSX15.1.sdk -### -c %s 2>&1 \
+// RUN: | FileCheck --check-prefixes=CC1,CXX,ULI,CI,UI,NO-FW -DSDKROOT=%S/Inputs/MacOSX15.1.sdk %s
+
+// If the user requests libc++, the MachO driver should still find the search path.
+// RUN: %clang -x c++ -stdlib=libc++ -target arm64-apple-none-macho -isysroot %S/Inputs/MacOSX15.1.sdk -### -c %s 2>&1 \
+// RUN: | FileCheck --check-prefixes=CC1,CXX,ULI,CI,UI,NO-FW -DSDKROOT=%S/Inputs/MacOSX15.1.sdk %s
+
+// Verify that embedded uses can swap in alternate usr/include and usr/local/include directories.
+// usr/local/include is specified in the driver as -internal-isystem, however, the driver generated
+// paths come before the paths in the driver arguments. In order to keep usr/local/include in the
+// same position, -isystem has to be used instead of -Xclang -internal-isystem. There isn't an
+// -externc-isystem, but it's ok to use -Xclang -internal-externc-isystem since the driver doesn't
+// use that if -nostdlibinc or -nostdinc is passed.
+// RUN: %clang -x c++ -stdlib=libc++ -target arm64-apple-none-macho -isysroot %S/Inputs/MacOSX15.1.sdk \
+// RUN:        -nostdlibinc -isystem %S/Inputs/MacOSX15.1.sdk/embedded/usr/local/include \
+// RUN:        -Xclang -internal-externc-isystem -Xclang %S/Inputs/MacOSX15.1.sdk/embedded/usr/include \
+// RUN:        -### -c %s 2>&1 | FileCheck --check-prefixes=CC1,NO-CXX,EULI,CI,EUI,NO-FW -DSDKROOT=%S/Inputs/MacOSX15.1.sdk %s
+
+
+// The ordering of these flags doesn't matter, and so this test is a little
+// fragile. i.e. all of the -internal-isystem paths will be searched before the
+// -internal-externc-isystem ones, and their order on the command line doesn't
+// matter. The line order here is just the current order that the driver writes
+// the cc1 arguments.
+
+// CC1: "-cc1"
+// NO-CXX-NOT: "-internal-isystem" "{{.*}}/include/c++/v1"
+// CXX-SAME: "-internal-isystem" "{{.*}}/include/c++/v1"
+// ULI-SAME: "-internal-isystem" "[[SDKROOT]]/usr/local/include"
+// EULI-SAME: "-isystem" "[[SDKROOT]]/embedded/usr/local/include"
+// CI-SAME: "-internal-isystem" "{{.*}}/clang/{{[[:digit:].]*}}/include"
+// UI-SAME: "-internal-externc-isystem" "[[SDKROOT]]/usr/include"
+// EUI-SAME: "-internal-externc-isystem" "[[SDKROOT]]/embedded/usr/include"
+// NO-FW-NOT: "-internal-iframework"
diff --git a/clang/test/Driver/darwin-embedded-search-paths.c b/clang/test/Driver/darwin-embedded-search-paths.c
index 7fa20501b52f39..bd651b7a1cd181 100644
--- a/clang/test/Driver/darwin-embedded-search-paths.c
+++ b/clang/test/Driver/darwin-embedded-search-paths.c
@@ -1,3 +1,4 @@
+// REQUIRES: !(default-cxx-stdlib=libc++)
 // UNSUPPORTED: system-windows
 //   Windows is unsupported because we use the Unix path separator `/` in the test.
 
@@ -6,7 +7,8 @@
 // RUN: %clang -x c -target arm64-apple-none-macho -isysroot %S/Inputs/MacOSX15.1.sdk -### -c %s 2>&1 \
 // RUN: | FileCheck --check-prefixes=CC1,NO-CXX,ULI,CI,UI,NO-FW -DSDKROOT=%S/Inputs/MacOSX15.1.sdk %s
 
-// Unlike the Darwin driver, the MachO driver doesn't default to libc++
+// Unlike the Darwin driver, the MachO driver doesn't default to libc++, and unless
+// CLANG_DEFAULT_CXX_STDLIB is libc++ it won't add any search paths.
 // RUN: %clang -x c++ -target arm64-apple-none-macho -isysroot %S/Inputs/MacOSX15.1.sdk -### -c %s 2>&1 \
 // RUN: | FileCheck --check-prefixes=CC1,NO-CXX,ULI,CI,UI,NO-FW -DSDKROOT=%S/Inputs/MacOSX15.1.sdk %s