[clang][PAC] ptrauth_qualifier must be a feature rather than an extension

Under `-pedantic-errors` extensions (as detected by __has_extension) are
not enabled (or rather the tests return false). As the ptrauth qualifier
impacts the ABI this is not sound, so this PR returns the ptrauth qualifier
to being detected through a feature check.

Author: ojhunt

clang/include/clang/Basic/Features.def

@@ -148,7 +148,7 @@ FEATURE(thread_sanitizer, LangOpts.Sanitize.has(SanitizerKind::Thread))
 FEATURE(dataflow_sanitizer, LangOpts.Sanitize.has(SanitizerKind::DataFlow))
 FEATURE(scudo, LangOpts.Sanitize.hasOneOf(SanitizerKind::Scudo))
 FEATURE(ptrauth_intrinsics, LangOpts.PointerAuthIntrinsics)
-EXTENSION(ptrauth_qualifier, LangOpts.PointerAuthIntrinsics)
+FEATURE(ptrauth_qualifier, LangOpts.PointerAuthIntrinsics)
 FEATURE(ptrauth_calls, LangOpts.PointerAuthCalls)
 FEATURE(ptrauth_returns, LangOpts.PointerAuthReturns)
 FEATURE(ptrauth_vtable_pointer_address_discrimination, LangOpts.PointerAuthVTPtrAddressDiscrimination)

clang/test/Preprocessor/ptrauth_extension.c

@@ -1,10 +1,16 @@
 // RUN: %clang_cc1 -E %s -triple=aarch64 -fptrauth-intrinsics | \
 // RUN:   FileCheck %s --check-prefixes=INTRIN
 
+// RUN: %clang_cc1 -E %s -triple=aarch64 -fptrauth-intrinsics -pedantic-errors | \
+// RUN:   FileCheck %s --check-prefixes=INTRIN
+
 // RUN: %clang_cc1 -E %s -triple=aarch64 -fptrauth-calls | \
 // RUN:   FileCheck %s --check-prefixes=NOINTRIN
 
-#if __has_extension(ptrauth_qualifier)
+// RUN: %clang_cc1 -E %s -triple=aarch64 -fptrauth-calls -pedantic-errors | \
+// RUN:   FileCheck %s --check-prefixes=NOINTRIN
+
+#if __has_feature(ptrauth_qualifier)
 // INTRIN: has_ptrauth_qualifier
 void has_ptrauth_qualifier() {}
 #else

clang/test/Sema/ptrauth-qualifier.c

@@ -1,7 +1,8 @@
 // RUN: %clang_cc1 -triple arm64-apple-ios -std=c23 -fsyntax-only -verify -fptrauth-intrinsics %s
 // RUN: %clang_cc1 -triple aarch64-linux-gnu -std=c23 -fsyntax-only -verify -fptrauth-intrinsics %s
+// RUN: %clang_cc1 -triple aarch64-linux-gnu -std=c23 -fsyntax-only -verify -fptrauth-intrinsics -pedantic-errors -DPEDANTIC_ERRORS %s
 
-#if !__has_extension(ptrauth_qualifier)
+#if !__has_feature(ptrauth_qualifier)
 // This error means that the __ptrauth qualifier availability test says  that it
 // is not available. This error is not expected in the output, if it is seen
 // there is a feature detection regression.
@@ -66,13 +67,15 @@ intp redeclaration3 = 0;                       // expected-error{{redefinition o
 void illegal0(intp __ptrauth(VALID_DATA_KEY)); // expected-error {{parameter type may not be qualified with '__ptrauth'; type is '__ptrauth(2,0,0) intp' (aka 'int *__ptrauth(2,0,0)')}}
 intp __ptrauth(VALID_DATA_KEY) illegal1(void); // expected-error {{return type may not be qualified with '__ptrauth'; type is '__ptrauth(2,0,0) intp' (aka 'int *__ptrauth(2,0,0)')}}
 
+#ifndef PEDANTIC_ERRORS
 static_assert(_Generic(typeof(valid0), int * __ptrauth(VALID_DATA_KEY) : 1, int * : 0, default : 0));
 static_assert(_Generic(typeof(valid0), int * __ptrauth(VALID_CODE_KEY) : 0, default : 1));
 static_assert(_Generic(typeof_unqual(valid0), int * __ptrauth(VALID_DATA_KEY) : 0, int * : 1, default : 0));
 static_assert(_Generic(valid0, int * __ptrauth(VALID_DATA_KEY) : 0, int * : 1, default : 0)); // expected-warning {{association of type 'int *__ptrauth(2,0,0)' will never be selected}}
 
 static_assert(_Generic(array0, int * __ptrauth(VALID_DATA_KEY) * : 1, default : 0));
 static_assert(_Generic(*array1, int * : 1, default : 0));
+#endif
 
 void test_code(intp p) {
   p = (intp __ptrauth(VALID_DATA_KEY)) 0; // expected-error {{cannot cast to '__ptrauth'-qualified type '__ptrauth(2,0,0) intp' (aka 'int *__ptrauth(2,0,0)')}}
@@ -99,8 +102,10 @@ void test_array(void) {
 __attribute__((overloadable)) int overload_func(int **);
 __attribute__((overloadable)) float overload_func(int * __ptrauth(VALID_DATA_KEY) *);
 
+#ifndef PEDANTIC_ERRORS
 static_assert(_Generic(typeof(overload_func(&ptr0)), int : 1, default : 0));
 static_assert(_Generic(typeof(overload_func(&valid0)), float : 1, default : 0));
+#endif
 
 void func(int array[__ptrauth(VALID_DATA_KEY) 10]); // expected-error {{'__ptrauth' qualifier only applies to pointer or pointer sized integer types; 'int[10]' is invalid}}
 

clang/test/SemaObjC/ptrauth-qualifier.m

@@ -1,7 +1,8 @@
 // RUN: %clang_cc1 -triple arm64-apple-ios -fsyntax-only -verify -fptrauth-intrinsics %s
 // RUN: %clang_cc1 -triple aarch64-linux-gnu -fsyntax-only -verify -fptrauth-intrinsics %s
+// RUN: %clang_cc1 -triple aarch64-linux-gnu -fsyntax-only -verify -fptrauth-intrinsics -pedantic-errors %s
 
-#if !__has_extension(ptrauth_qualifier)
+#if !__has_feature(ptrauth_qualifier)
 // This error means that the __ptrauth qualifier availability test says  that it
 // is not available. This error is not expected in the output, if it is seen
 // there is a feature detection regression.