Handle char{8,16,32} and wchar_t in ASTContext::getIntegerRank()

[hans]

Summary

They were previously not handled, causing the llvm_unreachable with "getIntegerRank(): not a built-in integer" message to be hit.

The test case is derived from how we hit it in Chromium (crbug.com/1396142). I tried to come up with something more direct, but this is the best I could find.

[tahonermann]

The direction of the changes looks right. I noted a couple of minor considerations.

clang/lib/AST/ASTContext.cpp

7109

This should technically be UnsignedCharTy though it probably doesn't matter.

clang/test/SemaCXX/vector-bool.cpp

93–104 ↗

(On Diff #480462)

This source file purports to be specific to vectors with bool element type. These additions look like they would be more at home in clang/test/SemaCXX/vector.cpp.

[hans]

Address comments.

clang/lib/AST/ASTContext.cpp

7109

Done.

clang/test/SemaCXX/vector-bool.cpp

93–104 ↗

(On Diff #480462)

Done.

[tahonermann]

Looks good to me!

clang/lib/AST/ASTContext.cpp

unsigned ASTContext::getIntegerRank(const Type *T) const {
   case BuiltinType::ULong:
     return 5 + (getIntWidth(LongTy) << 3);
   case BuiltinType::LongLong:
   case BuiltinType::ULongLong:
     return 6 + (getIntWidth(LongLongTy) << 3);
   case BuiltinType::Int128:
   case BuiltinType::UInt128:
     return 7 + (getIntWidth(Int128Ty) << 3);
+
+  // "The ranks of char8_t, char16_t, char32_t, and wchar_t equal the ranks of
+  // their underlying types" [c++20 conv.rank]
+  case BuiltinType::Char8:
+    return getIntegerRank(UnsignedCharTy.getTypePtr());
+  case BuiltinType::Char16:
+    return getIntegerRank(
+        getFromTargetType(Target->getChar16Type()).getTypePtr());
+  case BuiltinType::Char32:
+    return getIntegerRank(
+        getFromTargetType(Target->getChar32Type()).getTypePtr());
+  case BuiltinType::WChar_S:
+  case BuiltinType::WChar_U:
+    return getIntegerRank(
+        getFromTargetType(Target->getWCharType()).getTypePtr());
   }
 }
 
 /// Whether this is a promotable bitfield reference according
 /// to C99 6.3.1.1p2, bullet 2 (and GCC extensions).
 ///
 /// \returns the type this bit-field will promote to, or NULL if no
 /// promotion occurs.

clang/test/SemaCXX/vector.cpp

 // RUN: %clang_cc1 -flax-vector-conversions=all -triple x86_64-apple-darwin10 -fsyntax-only -verify %s
 // RUN: %clang_cc1 -flax-vector-conversions=all -triple x86_64-apple-darwin10 -fsyntax-only -verify -std=c++98 %s
 // RUN: %clang_cc1 -flax-vector-conversions=all -triple x86_64-apple-darwin10 -fsyntax-only -verify -std=c++11 %s
+// RUN: %clang_cc1 -flax-vector-conversions=all -triple x86_64-apple-darwin10 -fsyntax-only -verify -std=c++20 %s
 // RUN: %clang_cc1 -flax-vector-conversions=integer -triple x86_64-apple-darwin10 -fsyntax-only -verify %s -DNO_LAX_FLOAT
 // RUN: %clang_cc1 -flax-vector-conversions=none -triple x86_64-apple-darwin10 -fsyntax-only -verify %s -DNO_LAX_FLOAT -DNO_LAX_INT
 
 typedef char char16 __attribute__ ((__vector_size__ (16)));
 typedef long long longlong16 __attribute__ ((__vector_size__ (16)));
 typedef char char16_e __attribute__ ((__ext_vector_type__ (16)));
 typedef long long longlong16_e __attribute__ ((__ext_vector_type__ (2)));
 
struct S {
   int (__attribute__((vector_size(I))) b);
   T (__attribute__((vector_size(I))) c);
 };
 
 void use() {
   S<int, 16> s;
 }
 } // namespace PR48540
+
+#if __cplusplus >= 202002L // C++20 or later
+// Don't crash due to missing integer ranks.
+char8_t v1 __attribute__((vector_size(16)));
+char16_t v2 __attribute__((vector_size(16)));
+char32_t v3 __attribute__((vector_size(16)));
+wchar_t v4 __attribute__((vector_size(16)));
+void triggerIntegerRankCheck() {
+  auto b1 = (v1 >= 0x12);
+  auto b2 = (v2 >= 0x12);
+  auto b3 = (v3 >= 0x12);
+  auto b4 = (v4 >= 0x12);
+}
+#endif