Match against all plugins when parsing microsoft attributes

clang/docs/ReleaseNotes.rst

@@ -345,6 +345,9 @@ Bug Fixes to Compiler Builtins
 Bug Fixes to Attribute Support
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+- Clang now correctly matches plugin attributes with Microsoft ``[attribute]`` syntax.
+  (#GH86422)
+
 Bug Fixes to C++ Support
 ^^^^^^^^^^^^^^^^^^^^^^^^
 

clang/examples/CMakeLists.txt

@@ -10,4 +10,5 @@ if(CLANG_PLUGIN_SUPPORT)
   add_subdirectory(Attribute)
   add_subdirectory(CallSuperAttribute)
   add_subdirectory(PluginsOrder)
+  add_subdirectory(MicrosoftAttributes)
 endif()

clang/examples/MicrosoftAttributes/CMakeLists.txt

@@ -0,0 +1,11 @@
+add_llvm_library(MicrosoftAttributes MODULE MicrosoftAttributes.cpp PLUGIN_TOOL clang)
+
+if(WIN32 OR CYGWIN)
+  target_link_libraries(MicrosoftAttributes PRIVATE
+    clangAST
+    clangBasic
+    clangFrontend
+    clangLex
+    LLVMSupport
+    )
+endif()

clang/examples/MicrosoftAttributes/MicrosoftAttributes.cpp

@@ -0,0 +1,61 @@
+//===- Attribute.cpp ------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Example clang plugin which adds an an annotation to class declarations
+// with a microsoft style '[example]' attribute.
+//
+// This plugin is used by clang/test/Frontend/ms-attributes tests.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Attr.h"
+#include "clang/Sema/ParsedAttr.h"
+#include "clang/Sema/Sema.h"
+#include "clang/Sema/SemaDiagnostic.h"
+#include "llvm/IR/Attributes.h"
+
+using namespace clang;
+
+namespace {
+
+struct ExampleAttrInfo : public ParsedAttrInfo {
+  ExampleAttrInfo() {
+    // Can take up to 1 optional argument.
+    OptArgs = 1;
+
+    // Only Microsoft-style [ms_example] supported.
+    // e.g.:
+    // [ms_example] class C {};
+    // [ms_example] void f() {}
+    static constexpr Spelling S[] = {{ParsedAttr::AS_Microsoft, "ms_example"}};
+    Spellings = S;
+  }
+
+  bool diagAppertainsToDecl(Sema &S, const ParsedAttr &Attr,
+                            const Decl *D) const override {
+    // This attribute can be applied to any declaration.
+    if (!isa<CXXRecordDecl>(D)) {
+      S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type_str)
+          << Attr << Attr.isRegularKeywordAttribute() << "classes";
+    }
+    return true;
+  }
+
+  AttrHandling handleDeclAttribute(Sema &S, Decl *D,
+                                   const ParsedAttr &Attr) const override {
+    // Add an annotation to the declaration.
+    D->addAttr(AnnotateAttr::Create(S.Context, "ms_example", nullptr, 0,
+                                    Attr.getRange()));
+    return AttributeApplied;
+  }
+};
+
+} // namespace
+
+static ParsedAttrInfoRegistry::Add<ExampleAttrInfo> Y("microsoft-example", "");

clang/lib/Parse/ParseDeclCXX.cpp

@@ -5061,11 +5061,12 @@ void Parser::ParseMicrosoftAttributes(ParsedAttributes &Attrs) {
         IdentifierInfo *II = Tok.getIdentifierInfo();
         SourceLocation NameLoc = Tok.getLocation();
         ConsumeToken();
-        ParsedAttr::Kind AttrKind =
-            ParsedAttr::getParsedKind(II, nullptr, ParsedAttr::AS_Microsoft);
+
         // For HLSL we want to handle all attributes, but for MSVC compat, we
         // silently ignore unknown Microsoft attributes.
-        if (getLangOpts().HLSL || AttrKind != ParsedAttr::UnknownAttribute) {
+        int Attr = hasAttribute(AttributeCommonInfo::Syntax::AS_Microsoft,
+                                nullptr, II, getTargetInfo(), getLangOpts());
+        if (getLangOpts().HLSL || Attr != 0) {
           bool AttrParsed = false;
           if (Tok.is(tok::l_paren)) {
             CachedTokens OpenMPTokens;

clang/test/CMakeLists.txt

@@ -79,7 +79,7 @@ list(APPEND CLANG_TEST_DEPS
   diagtool
   hmaptool
   )
-  
+
 if(CLANG_ENABLE_STATIC_ANALYZER)
   list(APPEND CLANG_TEST_DEPS
     clang-check
@@ -98,6 +98,7 @@ if(CLANG_BUILD_EXAMPLES AND CLANG_PLUGIN_SUPPORT)
   list(APPEND CLANG_TEST_DEPS
     Attribute
     AnnotateFunctions
+    MicrosoftAttributes
     CallSuperAttr
     PluginsOrder
     PrintFunctionNames

clang/test/Frontend/ms-attributes.cpp

@@ -0,0 +1,6 @@
+// RUN: %clang -fplugin=%llvmshlibdir/MicrosoftAttributes%pluginext -fsyntax-only -fms-extensions -E %s | FileCheck %s
+// REQUIRES: plugins, examples
+// expected-no-diagnostics
+[ms_example]
+class C {};
+// CHECK: AnnotateAttr{{.*}} "ms_example"