[cxx-interop] Support char8_t C++20 type

egorzhdan · egorzhdan · commit fcb590690e46 · 2024-09-27T13:56:03.000+01:00
https://en.cppreference.com/w/cpp/keyword/char8_t This is based on a patch from Varun Gandhi: swiftlang#26153 rdar://39988329 / resolves swiftlang#68726
diff --git a/include/swift/ClangImporter/BuiltinMappedTypes.def b/include/swift/ClangImporter/BuiltinMappedTypes.def
@@ -47,6 +47,7 @@ MAP_BUILTIN_INTEGER_TYPE(UInt,      CUnsignedInt)
 MAP_BUILTIN_INTEGER_TYPE(ULong,     CUnsignedLong)
 MAP_BUILTIN_INTEGER_TYPE(ULongLong, CUnsignedLongLong)
 MAP_BUILTIN_INTEGER_TYPE(UInt128,   CUnsignedInt128)
+MAP_BUILTIN_INTEGER_TYPE(Char8,     CChar8)
 MAP_BUILTIN_INTEGER_TYPE(Char16,    CChar16)
 MAP_BUILTIN_INTEGER_TYPE(Char32,    CChar32)
 MAP_BUILTIN_INTEGER_TYPE(SChar,     CSignedChar)
diff --git a/include/swift/PrintAsClang/ClangMacros.def b/include/swift/PrintAsClang/ClangMacros.def
@@ -73,6 +73,7 @@
 #endif
 
 CLANG_MACRO_DEFINED("SWIFT_TYPEDEFS")
+CLANG_MACRO_DEFINED("char8_t")
 CLANG_MACRO_DEFINED("char16_t")
 CLANG_MACRO_DEFINED("char32_t")
 
diff --git a/lib/ClangImporter/ImportMacro.cpp b/lib/ClangImporter/ImportMacro.cpp
@@ -301,6 +301,8 @@ builtinTypeForToken(const clang::Token &tok, const clang::ASTContext &context) {
     return clang::QualType(context.WCharTy);
   case clang::tok::kw_bool:
     return clang::QualType(context.BoolTy);
+  case clang::tok::kw_char8_t:
+    return clang::QualType(context.Char8Ty);
   case clang::tok::kw_char16_t:
     return clang::QualType(context.Char16Ty);
   case clang::tok::kw_char32_t:
diff --git a/lib/ClangImporter/ImportType.cpp b/lib/ClangImporter/ImportType.cpp
@@ -312,7 +312,6 @@ namespace {
       case clang::BuiltinType::BFloat16:
       case clang::BuiltinType::Float128:
       case clang::BuiltinType::NullPtr:
-      case clang::BuiltinType::Char8:
       case clang::BuiltinType::Ibm128:
         return Type();
 
diff --git a/lib/PrintAsClang/PrimitiveTypeMapping.cpp b/lib/PrintAsClang/PrimitiveTypeMapping.cpp
@@ -38,6 +38,7 @@ void PrimitiveTypeMapping::initialize(ASTContext &ctx) {
 
   MAP(CChar, "char", false);
   MAP(CWideChar, "wchar_t", false);
+  MAP(CChar8, "char8_t", false);
   MAP(CChar16, "char16_t", false);
   MAP(CChar32, "char32_t", false);
 
diff --git a/lib/PrintAsClang/PrintAsClang.cpp b/lib/PrintAsClang/PrintAsClang.cpp
@@ -138,6 +138,7 @@ static void writePrologue(raw_ostream &out, ASTContext &ctx,
          "# if __has_include(<uchar.h>)\n"
          "#  include <uchar.h>\n"
          "# elif !defined(__cplusplus)\n"
+         "typedef unsigned char char8_t;\n"
          "typedef uint_least16_t char16_t;\n"
          "typedef uint_least32_t char32_t;\n"
          "# endif\n"
diff --git a/stdlib/public/core/CTypes.swift b/stdlib/public/core/CTypes.swift
@@ -134,6 +134,9 @@ public typealias CWideChar = UInt16
 public typealias CWideChar = Unicode.Scalar
 #endif
 
+/// The C++20 'char8_t' type, which has UTF-8 encoding.
+public typealias CChar8 = UInt8
+
 // FIXME: Swift should probably have a UTF-16 type other than UInt16.
 //
 /// The C++11 'char16_t' type, which has UTF-16 encoding.
diff --git a/test/IRGen/objc_type_encoding.swift b/test/IRGen/objc_type_encoding.swift
@@ -74,10 +74,10 @@ import gizmo
 // CHECK-watchos: private unnamed_addr constant [23 x i8] c"v44@0:8C16S20I24Q28Q36\00"
 // CHECK-xros: private unnamed_addr constant [23 x i8] c"v44@0:8C16S20I24Q28Q36\00"
 
-  @objc func testCChars(_ basic: CChar, wchar wide: CWideChar, char16: CChar16, char32: CChar32) {}
-// CHECK-macosx: private unnamed_addr constant [20 x i8] c"v32@0:8c16i20S24i28\00"
-// CHECK-ios: private unnamed_addr constant [20 x i8] c"v32@0:8c16i20S24i28\00"
-// CHECK-tvos: private unnamed_addr constant [20 x i8] c"v32@0:8c16i20S24i28\00"
+  @objc func testCChars(_ basic: CChar, wchar wide: CWideChar, char8: CChar8, char16: CChar16, char32: CChar32) {}
+// CHECK-macosx: private unnamed_addr constant [23 x i8] c"v36@0:8c16i20C24S28i32\00"
+// CHECK-ios: private unnamed_addr constant [23 x i8] c"v36@0:8c16i20C24S28i32\00"
+// CHECK-tvos: private unnamed_addr constant [23 x i8] c"v36@0:8c16i20C24S28i32\00"
 // CHECK-watchos: private unnamed_addr constant [20 x i8] c"v32@0:8c16i20S24i28\00"
 // CHECK-xros: private unnamed_addr constant [20 x i8] c"v32@0:8c16i20S24i28\00"
 
diff --git a/test/Interop/C/chars/Inputs/import-cchar-types.h b/test/Interop/C/chars/Inputs/import-cchar-types.h
@@ -6,4 +6,8 @@
 extern char a_char;
 extern wchar_t a_wchar;
 
+#if __cplusplus
+extern char8_t small_char;
+#endif
+
 #endif // TEST_INTEROP_C_CHARS_INPUTS_IMPORT_CCHAR_TYPES_H
diff --git a/test/Interop/C/chars/import-cchar-types.swift b/test/Interop/C/chars/import-cchar-types.swift
@@ -1,4 +1,7 @@
 // RUN: %target-swift-ide-test -print-module -module-to-print=ImportCCharTypes -I %S/Inputs -source-filename=x | %FileCheck %s
+// RUN: %target-swift-ide-test -print-module -module-to-print=ImportCCharTypes -I %S/Inputs -source-filename=x -cxx-interoperability-mode=default -Xcc -std=c++20 | %FileCheck %s --check-prefix=CHECK-CXX
 
 // CHECK: var a_char: CChar
 // CHECK: var a_wchar: wchar_t
+
+// CHECK-CXX: var small_char: UInt8
diff --git a/test/PrintAsObjC/classes.swift b/test/PrintAsObjC/classes.swift
@@ -204,7 +204,7 @@ class NotObjC {}
 // CHECK-NEXT: - (void)testSelector:(SEL _Nonnull)sel boolean:(BOOL)b;
 // CHECK-NEXT: - (void)testCSignedTypes:(signed char)a b:(short)b c:(int)c d:(long)d e:(long long)e;
 // CHECK-NEXT: - (void)testCUnsignedTypes:(unsigned char)a b:(unsigned short)b c:(unsigned int)c d:(unsigned long)d e:(unsigned long long)e;
-// CHECK-NEXT: - (void)testCChars:(char)basic wchar:(wchar_t)wide char16:(char16_t)char16 char32:(char32_t)char32;
+// CHECK-NEXT: - (void)testCChars:(char)basic wchar:(wchar_t)wide char8:(char8_t)char8 char16:(char16_t)char16 char32:(char32_t)char32;
 // CHECK-NEXT: - (void)testCFloats:(float)a b:(double)b;
 // CHECK-NEXT: - (void)testCBool:(bool)a;
 // CHECK-NEXT: - (void)testSizedSignedTypes:(int8_t)a b:(int16_t)b c:(int32_t)c d:(int64_t)d;
@@ -250,7 +250,7 @@ class NotObjC {}
 
   @objc func testCSignedTypes(_ a: CSignedChar, b: CShort, c: CInt, d: CLong, e: CLongLong) {}
   @objc func testCUnsignedTypes(_ a: CUnsignedChar, b: CUnsignedShort, c: CUnsignedInt, d: CUnsignedLong, e: CUnsignedLongLong) {}
-  @objc func testCChars(_ basic: CChar, wchar wide: CWideChar, char16: CChar16, char32: CChar32) {}
+  @objc func testCChars(_ basic: CChar, wchar wide: CWideChar, char8: CChar8, char16: CChar16, char32: CChar32) {}
   @objc func testCFloats(_ a: CFloat, b: CDouble) {}
   @objc func testCBool(_ a: CBool) {}
 
diff --git a/test/stdlib/PrintInteger.swift b/test/stdlib/PrintInteger.swift
@@ -39,6 +39,7 @@ PrintTests.test("CustomStringConvertible") {
 #else
   hasDescription(CWideChar(42)!)
 #endif
+  hasDescription(CChar8(42))
   hasDescription(CChar16(42))
   hasDescription(CChar32(42)!)
 }
@@ -60,6 +61,7 @@ PrintTests.test("Printable") {
 #else
   expectPrinted("*", CWideChar(42)!)
 #endif
+  expectPrinted("42", CChar8(42))
   expectPrinted("42", CChar16(42))
   expectPrinted("*", CChar32(42)!)
 
@@ -155,6 +157,7 @@ PrintTests.test("Printable") {
 #else
   expectPrinted("*", CWideChar(42)!)
 #endif
+  expectPrinted("42", CChar8(42))
   expectPrinted("42", CChar16(42))
   expectPrinted("*", CChar32(42)!)
 }
