[PATCH] D139632: [clang-cl] Ignore #pragma managed / #pragma unmanaged

[Sylvain Audi via Phabricator via cfe-commits]

saudi created this revision.
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Those 2 pragmas are ignored by MSVC when not compiling with `/CLR`, which clang doesn't support.
Ignore them in clang `-fms-extensions`, to avoid `-Wunknown-pragma` warnings.

See https://learn.microsoft.com/en-us/cpp/preprocessor/managed-unmanaged?view=msvc-170


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D139632

Files:
  clang/lib/Lex/Pragma.cpp
  clang/test/Preprocessor/pragma_microsoft.c


Index: clang/test/Preprocessor/pragma_microsoft.c
===================================================================
--- clang/test/Preprocessor/pragma_microsoft.c
+++ clang/test/Preprocessor/pragma_microsoft.c
@@ -235,6 +235,12 @@
 #pragma optimize("", on) // expected-error {{'#pragma optimize' can only appear at file scope}}
 }
 
+#pragma managed            // no-warning
+#pragma unmanaged          // no-warning
+#pragma managed(push, on)  // no-warning
+#pragma managed(pop)       // no-warning
+#pragma managed2           // expected-warning{{unknown pragma ignored}}
+
 #pragma execution_character_set                 // expected-warning {{expected '('}}
 #pragma execution_character_set(                // expected-warning {{expected 'push' or 'pop'}}
 #pragma execution_character_set()               // expected-warning {{expected 'push' or 'pop'}}
Index: clang/lib/Lex/Pragma.cpp
===================================================================
--- clang/lib/Lex/Pragma.cpp
+++ clang/lib/Lex/Pragma.cpp
@@ -1957,6 +1957,15 @@
   }
 };
 
+/// "\#pragma managed"
+/// "\#pragma managed(...)"
+/// "\#pragma unmanaged"
+/// MSVC ignores this pragma when not compiling using /clr, which clang doesn't
+/// support. We parse it and ignore it to avoid -Wunknown-pragma warnings.
+struct PragmaManagedHandler : public EmptyPragmaHandler {
+  PragmaManagedHandler(const char *pragma) : EmptyPragmaHandler(pragma) {}
+};
+
 /// This handles parsing pragmas that take a macro name and optional message
 static IdentifierInfo *HandleMacroAnnotationPragma(Preprocessor &PP, Token &Tok,
                                                    const char *Pragma,
@@ -2129,6 +2138,8 @@
     AddPragmaHandler(new PragmaIncludeAliasHandler());
     AddPragmaHandler(new PragmaHdrstopHandler());
     AddPragmaHandler(new PragmaSystemHeaderHandler());
+    AddPragmaHandler(new PragmaManagedHandler("managed"));
+    AddPragmaHandler(new PragmaManagedHandler("unmanaged"));
   }
 
   // Pragmas added by plugins


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