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

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

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(CharTy.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-bool.cpp

-// RUN: %clang_cc1 -triple x86_64-linux-pc -fsyntax-only -verify -fexceptions -fcxx-exceptions %s -std=c++17
+// RUN: %clang_cc1 -triple x86_64-linux-pc -fsyntax-only -verify -fexceptions -fcxx-exceptions %s -std=c++20
 // Note that this test depends on the size of long-long to be different from
 // int, so it specifies a triple.
 
 using FourShorts = short __attribute__((__vector_size__(8)));
 using TwoInts = int __attribute__((__vector_size__(8)));
 using EightInts = int __attribute__((__vector_size__(32)));
 using TwoUInts = unsigned __attribute__((__vector_size__(8)));
 using FourInts = int __attribute__((__vector_size__(16)));

 
 // Disallow element-wise access.
 bool* ElementRefs() {
   eight_bools.y = false; // expected-error@88 {{illegal vector component name ''y''}}
   &eight_bools.z;        // expected-error@89 {{illegal vector component name ''z''}}
   foo(eight_bools.w);    // expected-error@90 {{illegal vector component name ''w''}}
   foo(eight_bools.wyx);  // expected-error@91 {{illegal vector component name ''wyx''}}
 }
+
+// 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);
+}