[llvm-branch-commits] [clang] release/19.x: [clang][modules] Enable built-in modules for the upcoming Apple releases (#102239) (PR #102517)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-driver

Author: Ian Anderson (ian-twilightcoder)

<details>
<summary>Changes</summary>

Backport 961639962251de7428c3fe93fa17cfa6ab3c561a and 0f1361baf650641a59aaa1710d7a0b7b02f2e56d

Requested by: @<!-- -->ian-twilightcoder

---
Full diff: https://github.com/llvm/llvm-project/pull/102517.diff


4 Files Affected:

- (modified) clang/lib/Driver/ToolChains/Darwin.cpp (+30-7) 
- (added) clang/test/Driver/Inputs/DriverKit23.0.sdk/SDKSettings.json (+1) 
- (renamed) clang/test/Driver/Inputs/MacOSX15.0.sdk/SDKSettings.json () 
- (modified) clang/test/Driver/darwin-builtin-modules.c (+3-2) 


``````````diff
diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index c6f9d7beffb1db..17d57b2f7eedab 100644
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -2923,22 +2923,45 @@ bool Darwin::isAlignedAllocationUnavailable() const {
   return TargetVersion < alignedAllocMinVersion(OS);
 }
 
-static bool sdkSupportsBuiltinModules(const Darwin::DarwinPlatformKind &TargetPlatform, const std::optional<DarwinSDKInfo> &SDKInfo) {
+static bool sdkSupportsBuiltinModules(
+    const Darwin::DarwinPlatformKind &TargetPlatform,
+    const Darwin::DarwinEnvironmentKind &TargetEnvironment,
+    const std::optional<DarwinSDKInfo> &SDKInfo) {
+  if (TargetEnvironment == Darwin::NativeEnvironment ||
+      TargetEnvironment == Darwin::Simulator ||
+      TargetEnvironment == Darwin::MacCatalyst) {
+    // Standard xnu/Mach/Darwin based environments
+    // depend on the SDK version.
+  } else {
+    // All other environments support builtin modules from the start.
+    return true;
+  }
+
   if (!SDKInfo)
+    // If there is no SDK info, assume this is building against a
+    // pre-SDK version of macOS (i.e. before Mac OS X 10.4). Those
+    // don't support modules anyway, but the headers definitely
+    // don't support builtin modules either. It might also be some
+    // kind of degenerate build environment, err on the side of
+    // the old behavior which is to not use builtin modules.
     return false;
 
   VersionTuple SDKVersion = SDKInfo->getVersion();
   switch (TargetPlatform) {
+  // Existing SDKs added support for builtin modules in the fall
+  // 2024 major releases.
   case Darwin::MacOS:
-    return SDKVersion >= VersionTuple(99U);
+    return SDKVersion >= VersionTuple(15U);
   case Darwin::IPhoneOS:
-    return SDKVersion >= VersionTuple(99U);
+    return SDKVersion >= VersionTuple(18U);
   case Darwin::TvOS:
-    return SDKVersion >= VersionTuple(99U);
+    return SDKVersion >= VersionTuple(18U);
   case Darwin::WatchOS:
-    return SDKVersion >= VersionTuple(99U);
+    return SDKVersion >= VersionTuple(11U);
   case Darwin::XROS:
-    return SDKVersion >= VersionTuple(99U);
+    return SDKVersion >= VersionTuple(2U);
+
+  // New SDKs support builtin modules from the start.
   default:
     return true;
   }
@@ -3030,7 +3053,7 @@ void Darwin::addClangTargetOptions(
   // i.e. when the builtin stdint.h is in the Darwin module too, the cycle
   // goes away. Note that -fbuiltin-headers-in-system-modules does nothing
   // to fix the same problem with C++ headers, and is generally fragile.
-  if (!sdkSupportsBuiltinModules(TargetPlatform, SDKInfo))
+  if (!sdkSupportsBuiltinModules(TargetPlatform, TargetEnvironment, SDKInfo))
     CC1Args.push_back("-fbuiltin-headers-in-system-modules");
 
   if (!DriverArgs.hasArgNoClaim(options::OPT_fdefine_target_os_macros,
diff --git a/clang/test/Driver/Inputs/DriverKit23.0.sdk/SDKSettings.json b/clang/test/Driver/Inputs/DriverKit23.0.sdk/SDKSettings.json
new file mode 100644
index 00000000000000..7ba6c244df2115
--- /dev/null
+++ b/clang/test/Driver/Inputs/DriverKit23.0.sdk/SDKSettings.json
@@ -0,0 +1 @@
+{"Version":"23.0", "MaximumDeploymentTarget": "23.0.99"}
diff --git a/clang/test/Driver/Inputs/MacOSX99.0.sdk/SDKSettings.json b/clang/test/Driver/Inputs/MacOSX15.0.sdk/SDKSettings.json
similarity index 100%
rename from clang/test/Driver/Inputs/MacOSX99.0.sdk/SDKSettings.json
rename to clang/test/Driver/Inputs/MacOSX15.0.sdk/SDKSettings.json
diff --git a/clang/test/Driver/darwin-builtin-modules.c b/clang/test/Driver/darwin-builtin-modules.c
index 1c56e13bfb9293..ec515133be8aba 100644
--- a/clang/test/Driver/darwin-builtin-modules.c
+++ b/clang/test/Driver/darwin-builtin-modules.c
@@ -6,6 +6,7 @@
 // RUN: %clang -isysroot %S/Inputs/iPhoneOS13.0.sdk -target arm64-apple-ios13.0 -### %s 2>&1 | FileCheck %s
 // CHECK: -fbuiltin-headers-in-system-modules
 
-// RUN: %clang -isysroot %S/Inputs/MacOSX99.0.sdk -target x86_64-apple-macos98.0 -### %s 2>&1 | FileCheck --check-prefix=CHECK_FUTURE %s
-// RUN: %clang -isysroot %S/Inputs/MacOSX99.0.sdk -target x86_64-apple-macos99.0 -### %s 2>&1 | FileCheck --check-prefix=CHECK_FUTURE %s
+// RUN: %clang -isysroot %S/Inputs/MacOSX15.0.sdk -target x86_64-apple-macos14.0 -### %s 2>&1 | FileCheck --check-prefix=CHECK_FUTURE %s
+// RUN: %clang -isysroot %S/Inputs/MacOSX15.0.sdk -target x86_64-apple-macos15.0 -### %s 2>&1 | FileCheck --check-prefix=CHECK_FUTURE %s
+// RUN: %clang -isysroot %S/Inputs/DriverKit23.0.sdk -target arm64-apple-driverkit23.0 -### %s 2>&1 | FileCheck --check-prefix=CHECK_FUTURE %s
 // CHECK_FUTURE-NOT: -fbuiltin-headers-in-system-modules

``````````

</details>


https://github.com/llvm/llvm-project/pull/102517