[clang] [Darwin][Driver][clang] apple-none-macho orders the resource directory after internal-externc-isystem when nostdlibinc is used (PR #120507)

[Jon Roelofs via cfe-commits]

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@@ -0,0 +1,55 @@
+// UNSUPPORTED: system-windows
+//   Windows is unsupported because we use the Unix path separator `/` in the test.
+
+// Add default directories before running clang to check default
+// search paths.
+// RUN: rm -rf %t && mkdir -p %t
+// RUN: cp -R %S/Inputs/MacOSX15.1.sdk %t/
+// RUN: mkdir -p %t/MacOSX15.1.sdk/usr/include
+// RUN: mkdir -p %t/MacOSX15.1.sdk/usr/include/c++/v1
+// RUN: mkdir -p %t/MacOSX15.1.sdk/usr/local/include
+// RUN: mkdir -p %t/MacOSX15.1.sdk/embedded/usr/include
+// RUN: mkdir -p %t/MacOSX15.1.sdk/embedded/usr/local/include
+
+// Unlike the Darwin driver, the MachO driver doesn't add any framework search paths,
+// only the normal header ones.
+// RUN: %clang -xc %s -target arm64-apple-none-macho -isysroot %t/MacOSX15.1.sdk -E -v 2>&1 | FileCheck --check-prefix=CHECK-C %s
+//
+// CHECK-C:                 -isysroot [[SDKROOT:[^ ]*/MacOSX15.1.sdk]]
+// CHECK-C:                 #include <...> search starts here:
+// CHECK-C-NEXT:            [[SDKROOT]]/usr/local/include
+// CHECK-C-NEXT:            /clang/{{.*}}/include
+// CHECK-C-NEXT:            [[SDKROOT]]/usr/include
+
+// Unlike the Darwin driver, the MachO driver doesn't default to libc++
+// RUN: %clang -xc++ %s -target arm64-apple-none-macho -isysroot %t/MacOSX15.1.sdk -E -v 2>&1 | FileCheck --check-prefix=CHECK-CXX %s
+//
+// CHECK-CXX:               -isysroot [[SDKROOT:[^ ]*/MacOSX15.1.sdk]]
+// CHECK-CXX:               #include <...> search starts here:
+// CHECK-CXX-NEXT:          [[SDKROOT]]/usr/local/include
+// CHECK-CXX-NEXT:          /clang/{{.*}}/include
+// CHECK-CXX-NEXT:          [[SDKROOT]]/usr/include
+
+// However, if the user requests libc++, the MachO driver should find the search path.
+// RUN: %clang -xc++ -stdlib=libc++ %s -target arm64-apple-none-macho -isysroot %t/MacOSX15.1.sdk -E -v 2>&1 | FileCheck --check-prefix=CHECK-LIBCXX %s
+//
+// CHECK-LIBCXX:            -isysroot [[SDKROOT:[^ ]*/MacOSX15.1.sdk]]
+// CHECK-LIBCXX:            #include <...> search starts here:
+// CHECK-LIBCXX-NEXT:       [[SDKROOT]]/usr/include/c++/v1
+// CHECK-LIBCXX-NEXT:       [[SDKROOT]]/usr/local/include
+// CHECK-LIBCXX-NEXT:       /clang/{{.*}}/include
+// CHECK-LIBCXX-NEXT:       [[SDKROOT]]/usr/include
+
+// 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 -xc++ -stdlib=libc++ %s -target arm64-apple-none-macho -isysroot %t/MacOSX15.1.sdk -nostdlibinc -isystem %t/MacOSX15.1.sdk/embedded/usr/local/include -Xclang -internal-externc-isystem -Xclang %t/MacOSX15.1.sdk/embedded/usr/include -E -v 2>&1 | FileCheck --check-prefix=CHECK-EMBEDDED %s
+//
+// CHECK-EMBEDDED:          -isysroot [[SDKROOT:[^ ]*/MacOSX15.1.sdk]]
----------------
jroelofs wrote:

if you pass `"-DSDKROOT=%t/MacOSX15.1.sdk"` as a `FileCheck` argument, then this can be just `[[SDKROOT]]`, and it'll avoid issues with spaces in the path to the build directory.

https://github.com/llvm/llvm-project/pull/120507