[clang][Driver][Darwin] Optionally use xcselect to find macOS SDK

clang/CMakeLists.txt

@@ -214,6 +214,44 @@ if(GCC_INSTALL_PREFIX AND NOT USE_DEPRECATED_GCC_INSTALL_PREFIX)
     "See https://github.com/llvm/llvm-project/pull/77537 for detail.")
 endif()
 
+cmake_dependent_option(CLANG_USE_XCSELECT "Use libxcselect to find the macOS SDK." OFF "APPLE" OFF)
+
+if(CLANG_USE_XCSELECT)
+  if(DEFAULT_SYSROOT)
+    message(FATAL_ERROR "Setting DEFAULT_SYSROOT is incompatible with CLANG_USE_XCSELECT.")
+  endif()
+
+  check_include_file(xcselect.h CLANG_HAVE_XCSELECT_H)
+  if(NOT CLANG_HAVE_XCSELECT_H)
+    message(FATAL_ERROR "CLANG_USE_XCSELECT is enabled but xcselect.h was not found.")
+  endif()
+
+  include(CheckSymbolExists)
+  list(APPEND CMAKE_REQUIRED_LIBRARIES xcselect)
+  check_symbol_exists(xcselect_host_sdk_path xcselect.h CLANG_HAVE_XCSELECT_HOST_SDK_PATH)
+  list(REMOVE_ITEM CMAKE_REQUIRED_LIBRARIES xcselect)
+
+  if(NOT CLANG_HAVE_XCSELECT_HOST_SDK_PATH)
+    message(FATAL_ERROR "CLANG_USE_XCSELECT is enabled but either libxcselect is not available "
+      "or it is missing xcselect_host_sdk_path.")
+  endif()
+
+  set(XCSELECT_VALID_POLICIES LATEST MATCHING_ONLY MATCHING_PREFERRED)
+  set(CLANG_XCSELECT_HOST_SDK_POLICY "LATEST" CACHE STRING
+    "Policy to use for xcselect. One of: ${XCSELECT_VALID_POLICIES}")
+  set_property(CACHE CLANG_XCSELECT_HOST_SDK_POLICY PROPERTY STRINGS ${XCSELECT_VALID_POLICIES})
+  string(TOUPPER ${CLANG_XCSELECT_HOST_SDK_POLICY} CLANG_XCSELECT_HOST_SDK_POLICY)
+  list(JOIN XCSELECT_VALID_POLICIES "|" XCSELECT_POLICY_REGEX)
+
+  if(NOT CLANG_XCSELECT_HOST_SDK_POLICY MATCHES "^XCSELECT_HOST_SDK_POLICY_(${XCSELECT_POLICY_REGEX})$")
+    if(NOT CLANG_XCSELECT_HOST_SDK_POLICY IN_LIST XCSELECT_VALID_POLICIES)
+      message(FATAL_ERROR
+        "CLANG_XCSELECT_HOST_SDK_POLICY (${CLANG_XCSELECT_HOST_SDK_POLICY}) must be one of: ${XCSELECT_VALID_POLICIES}")
+    endif()
+    set(CLANG_XCSELECT_HOST_SDK_POLICY "XCSELECT_HOST_SDK_POLICY_${CLANG_XCSELECT_HOST_SDK_POLICY}")
+  endif()
+endif()
+
 set(ENABLE_LINKER_BUILD_ID OFF CACHE BOOL "pass --build-id to ld")
 
 set(ENABLE_X86_RELAX_RELOCATIONS ON CACHE BOOL

clang/include/clang/Config/config.h.cmake

@@ -86,4 +86,10 @@
 /* Whether CIR is built into Clang */
 #cmakedefine01 CLANG_ENABLE_CIR
 
+/* Whether to use xcselect to find the macOS SDK */
+#cmakedefine CLANG_USE_XCSELECT
+
+/* Policy to use for xcselect */
+#cmakedefine CLANG_XCSELECT_HOST_SDK_POLICY ${CLANG_XCSELECT_HOST_SDK_POLICY}
+
 #endif

clang/lib/Driver/CMakeLists.txt

@@ -14,6 +14,10 @@ if(WIN32)
   set(system_libs version)
 endif()
 
+if(CLANG_USE_XCSELECT)
+  set(system_libs xcselect)
+endif()
+
 add_clang_library(clangDriver
   Action.cpp
   Compilation.cpp

clang/lib/Driver/ToolChains/Darwin.cpp

@@ -29,6 +29,10 @@
 #include "llvm/TargetParser/Triple.h"
 #include <cstdlib> // ::getenv
 
+#ifdef CLANG_USE_XCSELECT
+#include <xcselect.h> // ::xcselect_host_sdk_path
+#endif
+
 using namespace clang::driver;
 using namespace clang::driver::tools;
 using namespace clang::driver::toolchains;
@@ -2257,17 +2261,25 @@ void Darwin::AddDeploymentTarget(DerivedArgList &Args) const {
     // Warn if the path does not exist.
     if (!getVFS().exists(A->getValue()))
       getDriver().Diag(clang::diag::warn_missing_sysroot) << A->getValue();
-  } else {
-    if (char *env = ::getenv("SDKROOT")) {
-      // We only use this value as the default if it is an absolute path,
-      // exists, and it is not the root path.
-      if (llvm::sys::path::is_absolute(env) && getVFS().exists(env) &&
-          StringRef(env) != "/") {
-        Args.append(Args.MakeSeparateArg(
-            nullptr, Opts.getOption(options::OPT_isysroot), env));
-      }
+  } else if (const char *env = ::getenv("SDKROOT")) {
+    // We only use this value as the default if it is an absolute path,
+    // exists, and it is not the root path.
+    if (llvm::sys::path::is_absolute(env) && getVFS().exists(env) &&
+        StringRef(env) != "/") {
+      Args.append(Args.MakeSeparateArg(
+          nullptr, Opts.getOption(options::OPT_isysroot), env));
     }
   }
+#ifdef CLANG_USE_XCSELECT
+  else if (getTriple().isMacOSX()) {
+    char *p;
+    if (!::xcselect_host_sdk_path(CLANG_XCSELECT_HOST_SDK_POLICY, &p)) {
+      Args.append(Args.MakeSeparateArg(
+          nullptr, Opts.getOption(options::OPT_isysroot), p));
+      ::free(p);
+    }
+  }
+#endif
 
   // Read the SDKSettings.json file for more information, like the SDK version
   // that we can pass down to the compiler.

clang/test/CMakeLists.txt

@@ -10,6 +10,7 @@ llvm_canonicalize_cmake_booleans(
   CLANG_PLUGIN_SUPPORT
   CLANG_SPAWN_CC1
   CLANG_ENABLE_CIR
+  CLANG_USE_XCSELECT
   ENABLE_BACKTRACES
   LLVM_BUILD_EXAMPLES
   LLVM_BYE_LINK_INTO_TOOLS

clang/test/Driver/arc.c

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // RUN: not %clang -ObjC -target i386-apple-darwin10 -stdlib=libstdc++ -m32 -fobjc-arc %s -fsyntax-only 2>&1 | FileCheck %s
 // RUN: not %clang -x objective-c -target i386-apple-darwin10 -stdlib=libstdc++ -m32 -fobjc-arc %s -fsyntax-only 2>&1 | FileCheck %s
 // RUN: not %clang -x objective-c++ -target i386-apple-darwin10 -stdlib=libstdc++ -m32 -fobjc-arc %s -fsyntax-only 2>&1 | FileCheck %s

clang/test/Driver/clang-g-opts.c

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // RUN: %clang -### -S %s        2>&1 | FileCheck --check-prefix=CHECK-WITHOUT-G %s
 // RUN: %clang -### -S %s -g -target x86_64-linux-gnu 2>&1 \
 // RUN:             | FileCheck --check-prefix=CHECK-WITH-G %s

clang/test/Driver/clang-translation.c

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // RUN: %clang -target i386-unknown-unknown -### -S -O0 -Os %s -o %t.s -fverbose-asm -fvisibility=hidden 2>&1 | FileCheck -check-prefix=I386 %s
 // I386: "-triple" "i386-unknown-unknown"
 // I386: "-S"

clang/test/Driver/darwin-builtin-modules.c

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // Check that darwin passes -fbuiltin-headers-in-system-modules
 // when expected.
 

clang/test/Driver/darwin-debug-flags.c

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // RUN: env RC_DEBUG_OPTIONS=1 %clang -target i386-apple-darwin11 -I "path with \spaces" -g -Os %s  -emit-llvm -S -o - | FileCheck %s
 // RUN: touch %t.s
 // RUN: env RC_DEBUG_OPTIONS=1 %clang -### -target i386-apple-darwin11 -c -g %t.s 2>&1 | FileCheck -check-prefix=S %s

clang/test/Driver/darwin-header-search-system.cpp

@@ -1,4 +1,6 @@
 // UNSUPPORTED: system-windows
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
 
 // General tests that the system header search paths detected by the driver
 // and passed to CC1 are correct on Darwin platforms.

clang/test/Driver/darwin-ld-platform-version-macos.c

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // RUN: touch %t.o
 
 // RUN: %clang -target x86_64-apple-macos10.13 -fuse-ld=lld \

clang/test/Driver/darwin-ld.c

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // Check that ld gets arch_multiple.
 
 // RUN: %clang -target i386-apple-darwin9 -arch i386 -arch x86_64 %s -### -o foo 2> %t.log

clang/test/Driver/darwin-multiarch-arm.c

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // Check that we compile correctly with multiple ARM -arch options.
 //
 // RUN: %clang -target arm7-apple-darwin10 -### \

clang/test/Driver/darwin-objc-options.m

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // Check miscellaneous Objective-C options.
 
 // RUN: %clang -target x86_64-apple-darwin10 -S -### %s \

clang/test/Driver/darwin-version.c

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // RUN: %clang -target armv6-apple-darwin9 -c %s -### 2>&1 | \
 // RUN:   FileCheck --check-prefix=CHECK-VERSION-OSX %s
 // CHECK-VERSION-OSX: "armv6k-apple-macosx10.5.0"

clang/test/Driver/debug-options.c

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // Check to make sure clang is somewhat picky about -g options.
 
 // Linux.

clang/test/Driver/fsanitize.c

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // RUN: %clang --target=x86_64-linux-gnu -fsanitize=undefined -fsanitize-trap=undefined %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP
 // RUN: %clang --target=x86_64-linux-gnu -fsanitize=undefined -fsanitize-trap=undefined -fno-sanitize-trap=signed-integer-overflow %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP2
 // RUN: %clang --target=x86_64-linux-gnu -fsanitize=undefined -fsanitize-undefined-trap-on-error %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-UNDEFINED-TRAP

clang/test/Driver/macos-apple-silicon-slice-link-libs.cpp

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // RUN: %clang -### -target arm64-apple-macos10.7 %s 2>&1 | FileCheck -check-prefix=ARM64-10_7 %s
 // RUN: %clang -### -target x86_64-apple-macos10.7 %s 2>&1 | FileCheck -check-prefix=x86_64-10_7 %s
 // RUN: %clang -### -target arm64-apple-darwin6 %s 2>&1 | FileCheck -check-prefix=ARM64-10_7 %s

clang/test/Driver/target-triple-deployment.c

@@ -1,3 +1,6 @@
+// XFAIL: xcselect
+// FIXME: There's no reason why this should fail with CLANG_USE_XCSELECT.
+
 // RUN: touch %t.o
 // RUN: %clang -fuse-ld= -target x86_64-apple-macosx10.4 -mlinker-version=400 -### %t.o 2> %t.log
 // RUN: %clang -fuse-ld= -target x86_64-apple-darwin9 -mlinker-version=400 -### %t.o 2>> %t.log

clang/test/Driver/xcselect.c

@@ -0,0 +1,5 @@
+// REQUIRES: xcselect
+// RUN: %clang -target arm64-apple-darwin -c -### %s 2> %t.log
+// RUN: FileCheck %s <%t.log
+
+// CHECK: "-isysroot" "{{.*}}/SDKs/MacOSX{{([0-9]+(\.[0-9]+)?)?}}.sdk"

clang/test/lit.cfg.py

@@ -338,6 +338,8 @@ def calculate_arch_features(arch_string):
 if config.have_llvm_driver:
     config.available_features.add("llvm-driver")
 
+if config.use_xcselect:
+    config.available_features.add("xcselect")
 
 # Some tests perform deep recursion, which requires a larger pthread stack size
 # than the relatively low default of 192 KiB for 64-bit processes on AIX. The

clang/test/lit.site.cfg.py.in

@@ -44,6 +44,7 @@ config.standalone_build = @CLANG_BUILT_STANDALONE@
 config.ppc_linux_default_ieeelongdouble = @PPC_LINUX_DEFAULT_IEEELONGDOUBLE@
 config.have_llvm_driver = @LLVM_TOOL_LLVM_DRIVER_BUILD@
 config.substitutions.append(("%llvm-version-major", "@LLVM_VERSION_MAJOR@"))
+config.use_xcselect = @CLANG_USE_XCSELECT@
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)