diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -3487,6 +3487,38 @@
// Microsoft-related attributes
+def MSNoTlsGuard : InheritableAttr {
+ let LangOpts = [MicrosoftExt];
+ let Spellings = [CXX11<"msvc", "no_tls_guard">];
+ let Subjects = SubjectList<[Var], ErrorDiag>;
+ let Documentation = [MSNoTlsGuardDocs];
+ let SimpleHandler = 1;
+}
+
+def MSKnownSemantics : TypeAttr {
+ let LangOpts = [MicrosoftExt];
+ let Spellings = [CXX11<"msvc", "known_semantics">];
+ let Documentation = [MSKnownSemanticsDocs];
+ let SimpleHandler = 1;
+}
+
+def MSNoopDtor : InheritableAttr {
+ let LangOpts = [MicrosoftExt];
+ let Spellings = [CXX11<"msvc", "noop_dtor">];
+ let Subjects = SubjectList<[Function], ErrorDiag>;
+ let Documentation = [MSNoopDtorDocs];
+ let SimpleHandler = 1;
+}
+
+def MSConstexpr : DeclOrStmtAttr {
+ let LangOpts = [MicrosoftExt];
+ let Spellings = [CXX11<"msvc", "constexpr">];
+ let Subjects = SubjectList<[Function, Stmt], ErrorDiag,
+ "functions and statements">;
+ let Documentation = [MSConstexprDocs];
+ let SimpleHandler = 1;
+}
+
def MSNoVTable : InheritableAttr, TargetSpecificAttr<TargetMicrosoftCXXABI> {
let Spellings = [Declspec<"novtable">];
let Subjects = SubjectList<[CXXRecord]>;
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -3478,6 +3478,41 @@
}];
}
+def MSNoTlsGuardDocs : Documentation {
+ let Category = DocCatVariable;
+ let Content = [{
+This attribute can be added to a TLS variable to disable initialization
+test check in threads which existed before DLL was loaded.
+It applies behavior of '/Zc:tlsGuards-' flag to the variable.
+Has no effect on clang.
+ }];
+}
+
+def MSKnownSemanticsDocs : Documentation {
+ let Category = DocCatType;
+ let Content = [{
+This attribute tells MSVC compiler that the type trait specialization
+have the standard-mandated semantics.
+Has no effect on clang.
+ }];
+}
+
+def MSNoopDtorDocs : Documentation {
+ let Category = DocCatFunction;
+ let Content = [{
+This attribute tells MSVC compiler that the destructor have no effects.
+Has no effect on clang.
+ }];
+}
+
+def MSConstexprDocs : Documentation {
+ let Category = DocCatStmt;
+ let Content = [{
+This attribute allows MSVC compiler to use "externed constexpr".
+Has no effect on clang.
+ }];
+}
+
def MSNoVTableDocs : Documentation {
let Category = DocCatDecl;
let Content = [{
diff --git a/clang/lib/AST/TypePrinter.cpp b/clang/lib/AST/TypePrinter.cpp
--- a/clang/lib/AST/TypePrinter.cpp
+++ b/clang/lib/AST/TypePrinter.cpp
@@ -1745,6 +1745,7 @@
case attr::AddressSpace:
case attr::CmseNSCall:
case attr::AnnotateType:
+ case attr::MSKnownSemantics:
llvm_unreachable("This attribute should have been handled already");
case attr::NSReturnsRetained:
diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
--- a/clang/lib/Sema/SemaStmtAttr.cpp
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
@@ -290,6 +290,12 @@
return ::new (S.Context) UnlikelyAttr(S.Context, A);
}
+static Attr *handleMSConstexpr(Sema &S, Stmt *St, const ParsedAttr &A,
+ SourceRange Range) {
+ // Validation is in Sema::ActOnAttributedStmt().
+ return ::new (S.Context) MSConstexprAttr(S.Context, A);
+}
+
#define WANT_STMT_MERGE_LOGIC
#include "clang/Sema/AttrParsedAttrImpl.inc"
#undef WANT_STMT_MERGE_LOGIC
@@ -485,6 +491,8 @@
return handleLikely(S, St, A, Range);
case ParsedAttr::AT_Unlikely:
return handleUnlikely(S, St, A, Range);
+ case ParsedAttr::AT_MSConstexpr:
+ return handleMSConstexpr(S, St, A, Range);
default:
// N.B., ClangAttrEmitter.cpp emits a diagnostic helper that ensures a
// declaration attribute is not written on a statement, but this code is
diff --git a/clang/test/AST/msvc-attrs.cpp b/clang/test/AST/msvc-attrs.cpp
new file mode 100644
--- /dev/null
+++ b/clang/test/AST/msvc-attrs.cpp
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -fms-extensions -std=c++20 -DMSX -ast-dump %s | FileCheck %s
+// RUN: not %clang_cc1 -Werror=ignored-attributes -ast-dump %s 2>&1 | grep "8 errors generated"
+
+// CHECK: VarDecl 0x{{[0-9a-f]+}} <{{.*}}:[[@LINE+3]]:24, col:47> col:47 no_tls_guard_var
+// CHECK-NEXT: MSNoTlsGuardAttr 0x{{[0-9a-f]+}} <col:3, col:9>
+// CHECK-NEXT: ThreadAttr 0x{{[0-9a-f]+}} <col:35>
+[[msvc::no_tls_guard]] __declspec(thread) int no_tls_guard_var;
+
+// CHECK: MSKnownSemanticsAttr 0x{{[0-9a-f]+}} <col:10, col:16>
+// CHECK-NEXT: CXXRecordDecl 0x{{[0-9a-f]+}} <col:1, col:34> col:34
+struct [[msvc::known_semantics]] Struct {};
+
+// CHECK: TypeAliasDecl 0x{{[0-9a-f]+}} <line:[[@LINE+3]]:1, col:39> col:7 Int 'int'
+// CHECK-NEXT: BuiltinType 0x{{[0-9a-f]+}} 'int'
+// CHECK-NEXT: MSKnownSemanticsAttr 0x{{[0-9a-f]+}} <col:13, col:19>
+using Int [[msvc::known_semantics]] = int;
+
+struct Dtor {
+ // CHECK: CXXDestructorDecl 0x{{[0-9a-f]+}} <line:[[@LINE+3]]:23, col:32> col:23 ~Dtor 'void () noexcept'
+ // CHECK-NEXT: CompoundStmt 0x{{[0-9a-f]+}} <col:31, col:32>
+ // CHECK-NEXT: MSNoopDtorAttr 0x{{[0-9a-f]+}} <col:5, col:11>
+ [[msvc::noop_dtor]] ~Dtor() {}
+};
+
+// CHECK: FunctionDecl 0x{{[0-9a-f]+}} <line:[[@LINE+2]]:21, col:61> col:27 New1 'void *(void *)'
+// CHECK: MSConstexprAttr 0x{{[0-9a-f]+}} <col:3, col:9>
+[[msvc::constexpr]] void *New1(void *where) { return where; }
+
+// CHECK: FunctionDecl {{.*}} <line:[[@LINE+4]]:1, line:[[@LINE+6]]:1> line:[[@LINE+4]]:17 constexpr New2
+// CHECK-NEXT: CompoundStmt
+// CHECK-NEXT: AttributedStmt
+// CHECK-NEXT: MSConstexprAttr
+constexpr char *New2() {
+ [[msvc::constexpr]] return ::new char[1];
+}
diff --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
--- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -83,6 +83,9 @@
// CHECK-NEXT: LoaderUninitialized (SubjectMatchRule_variable_is_global)
// CHECK-NEXT: Lockable (SubjectMatchRule_record)
// CHECK-NEXT: MIGServerRoutine (SubjectMatchRule_function, SubjectMatchRule_objc_method, SubjectMatchRule_block)
+// CHECK-NEXT: MSConstexpr (SubjectMatchRule_function)
+// CHECK-NEXT: MSNoTlsGuard (SubjectMatchRule_variable)
+// CHECK-NEXT: MSNoopDtor (SubjectMatchRule_function)
// CHECK-NEXT: MSStruct (SubjectMatchRule_record)
// CHECK-NEXT: MaybeUndef (SubjectMatchRule_variable_is_parameter)
// CHECK-NEXT: MicroMips (SubjectMatchRule_function)