[Clang] __has_builtin should return false for aux triple builtins

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

Author: sarnex

clang/include/clang/Basic/Builtins.h

@@ -74,6 +74,7 @@ struct Info {
   const char *Features;
   HeaderDesc Header;
   LanguageID Langs;
+  bool operator==(const Info &Other) const;
 };
 
 /// Holds information about both target-independent and
@@ -268,6 +269,10 @@ class Context {
   /// for AuxTarget).
   unsigned getAuxBuiltinID(unsigned ID) const { return ID - TSRecords.size(); }
 
+  // Return true if the AuxBuiltin ID represents a target-specific builtin that
+  // is always unsupported on the default target.
+  bool isAuxBuiltinIDAlwaysUnsupportedOnDefaultTarget(unsigned ID) const;
+
   /// Returns true if this is a libc/libm function without the '__builtin_'
   /// prefix.
   static bool isBuiltinFunc(llvm::StringRef Name);

clang/lib/Basic/Builtins.cpp

@@ -41,6 +41,14 @@ static constexpr Builtin::Info BuiltinInfo[] = {
 #include "clang/Basic/Builtins.inc"
 };
 
+bool Builtin::Info::operator==(const Builtin::Info &Other) const {
+  auto StrCompare = [](StringRef A, StringRef B) { return A == B; };
+  return Name == Other.Name && StrCompare(Type, Other.Type) &&
+         StrCompare(Attributes, Other.Attributes) &&
+         StrCompare(Features, Other.Features) && Header.ID == Other.Header.ID &&
+         Langs == Other.Langs;
+}
+
 const Builtin::Info &Builtin::Context::getRecord(unsigned ID) const {
   if (ID < Builtin::FirstTSBuiltin)
     return BuiltinInfo[ID];
@@ -183,6 +191,17 @@ unsigned Builtin::Context::getRequiredVectorWidth(unsigned ID) const {
   return Width;
 }
 
+bool Builtin::Context::isAuxBuiltinIDAlwaysUnsupportedOnDefaultTarget(
+    unsigned ID) const {
+  assert(isAuxTargetBuiltinID(ID) && "Expected aux target builtin ID");
+  const auto &Record = getRecord(ID);
+  for (const auto &MainTargetBuiltin : TSRecords)
+    if (Record == MainTargetBuiltin)
+      return false;
+
+  return true;
+}
+
 bool Builtin::Context::isLike(unsigned ID, unsigned &FormatIdx,
                               bool &HasVAListArg, const char *Fmt) const {
   assert(Fmt && "Not passed a format string");

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 +1819,21 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
             // usual allocation and deallocation functions. Required by libc++
             return 201802;
           default:
+            // We may get here because of aux builtins which may not be
+            // supported on the default target, for example if we have an X86
+            // specific builtin and the current target is SPIR-V. Sometimes we
+            // rely on __has_builtin returning true when passed a builtin that
+            // is not supported on the default target due to LangOpts but is
+            // supported on the aux target. See
+            // test/Headers/__cpuidex_conflict.c for an example. If the builtin
+            // is an aux builtin and it can never be supported on the default
+            // target, __has_builtin should return false.
+            if (getBuiltinInfo().isAuxBuiltinID(BuiltinID) &&
+                getBuiltinInfo().isAuxBuiltinIDAlwaysUnsupportedOnDefaultTarget(
+                    BuiltinID))
+              return false;
             return Builtin::evaluateRequiredTargetFeatures(
-                getBuiltinInfo().getRequiredFeatures(II->getBuiltinID()),
+                getBuiltinInfo().getRequiredFeatures(BuiltinID),
                 getTargetInfo().getTargetOpts().FeatureMap);
           }
           return true;

clang/test/Preprocessor/builtin_aux_info.cpp

@@ -0,0 +1,12 @@
+// REQUIRES: spirv-registered-target
+// REQUIRES: x86-registered-target
+
+// 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
+
+// CHECK: GOOD
+#if __has_builtin(__builtin_ia32_pause)
+  BAD
+#else
+  GOOD
+#endif