[Clang] __has_builtin should return false for aux triple builtins (#121839)

Currently, `__has_builtin` will return true when passed a builtin that
is only supported on the aux target. I found this when `__has_builtin`
was called with an X86 builtin but the current target was SPIR-V.

We should instead return false for aux builtins.

---------

Signed-off-by: Sarnie, Nick <[email protected]>

Author: sarnex

clang/lib/Lex/PPMacroExpansion.cpp

@@ -1804,8 +1804,9 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
                                            diag::err_feature_check_malformed);
         if (!II)
           return false;
-        else if (II->getBuiltinID() != 0) {
-          switch (II->getBuiltinID()) {
+        auto BuiltinID = II->getBuiltinID();
+        if (BuiltinID != 0) {
+          switch (BuiltinID) {
           case Builtin::BI__builtin_cpu_is:
             return getTargetInfo().supportsCpuIs();
           case Builtin::BI__builtin_cpu_init:
@@ -1818,8 +1819,11 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
             // usual allocation and deallocation functions. Required by libc++
             return 201802;
           default:
+            // __has_builtin should return false for aux builtins.
+            if (getBuiltinInfo().isAuxBuiltinID(BuiltinID))
+              return false;
             return Builtin::evaluateRequiredTargetFeatures(
-                getBuiltinInfo().getRequiredFeatures(II->getBuiltinID()),
+                getBuiltinInfo().getRequiredFeatures(BuiltinID),
                 getTargetInfo().getTargetOpts().FeatureMap);
           }
           return true;

clang/test/Headers/__cpuidex_conflict.c

@@ -3,7 +3,9 @@
 // RUN: %clang_cc1 %s -ffreestanding -fms-extensions -fms-compatibility \
 // RUN:  -fms-compatibility-version=19.00 -triple x86_64-pc-windows-msvc -emit-llvm -o -
 // %clang_cc1 %s -ffreestanding -triple x86_64-w64-windows-gnu -fms-extensions -emit-llvm -o -
-// RUN: %clang_cc1 %s -ffreestanding -fopenmp -fopenmp-is-target-device -aux-triple x86_64-unknown-linux-gnu
+//
+// FIXME: See https://github.com/llvm/llvm-project/pull/121839
+// RUN: not %clang_cc1 %s -ffreestanding -fopenmp -fopenmp-is-target-device -aux-triple x86_64-unknown-linux-gnu
 
 typedef __SIZE_TYPE__ size_t;
 

clang/test/Preprocessor/builtin_aux_info.cpp

@@ -0,0 +1,18 @@
+// RUN: %clang_cc1 -fopenmp -triple=spirv64 -fopenmp-is-target-device \
+// RUN: -aux-triple x86_64-linux-unknown -E %s | FileCheck -implicit-check-not=BAD %s
+
+// RUN: %clang_cc1 -fopenmp -triple=nvptx64 -fopenmp-is-target-device \
+// RUN: -aux-triple x86_64-linux-unknown -E %s | FileCheck -implicit-check-not=BAD %s
+
+// RUN: %clang_cc1 -fopenmp -triple=amdgcn-amd-amdhsa -fopenmp-is-target-device \
+// RUN: -aux-triple x86_64-linux-unknown -E %s | FileCheck -implicit-check-not=BAD %s
+
+// RUN: %clang_cc1 -fopenmp -triple=aarch64 -fopenmp-is-target-device \
+// RUN: -aux-triple x86_64-linux-unknown -E %s | FileCheck -implicit-check-not=BAD %s
+
+// CHECK: GOOD
+#if __has_builtin(__builtin_ia32_pause)
+  BAD
+#else
+  GOOD
+#endif