[PATCH] D52849: [SEMA] split ExtWarn dupl-decl-spec's into Extension and ExtWarn

[Nick Desaulniers via Phabricator via cfe-commits]

nickdesaulniers created this revision.
nickdesaulniers added a reviewer: rsmith.
Herald added a subscriber: cfe-commits.

For types deduced from typedef's and typeof's, don't warn for duplicate
declaration specifiers in C90 unless -pedantic.

Create a third diagnostic type for duplicate declaration specifiers.
Previously, we had an ExtWarn and a Warning. This change adds a third,
Extension, which only warns when -pedantic is set, staying silent
otherwise.

Fixes PR32985.


Repository:
  rC Clang

https://reviews.llvm.org/D52849

Files:
  include/clang/Basic/DiagnosticSemaKinds.td
  lib/Parse/ParseDecl.cpp
  lib/Sema/DeclSpec.cpp
  test/Sema/pr32985.c


Index: test/Sema/pr32985.c
===================================================================
--- /dev/null
+++ test/Sema/pr32985.c
@@ -0,0 +1,20 @@
+/*
+RUN: %clang_cc1 %s -std=gnu89 -fsyntax-only 2>&1 | FileCheck -check-prefix=CHECK-GNU89 %s -allow-empty
+RUN: %clang_cc1 %s -std=gnu89 -pedantic -fsyntax-only 2>&1 | FileCheck -check-prefix=CHECK-GNU89-PEDANTIC %s
+*/
+
+typedef const int t;
+const t c_i;
+/*
+CHECK-GNU89-NOT: 7:1: warning: duplicate 'const' declaration specifier
+CHECK-GNU89-PEDANTIC: 7:1: warning: duplicate 'const' declaration specifier
+*/
+
+const int c_i2;
+const typeof(c_i2) c_i3;
+/*
+CHECK-GNU89-NOT: 14:7: warning: extension used
+CHECK-GNU89-NOT: 14:1: warning: duplicate 'const' declaration specifier
+CHECK-GNU89-PEDANTIC: 14:7: warning: extension used
+CHECK-GNU89-PEDANTIC: 14:1: warning: duplicate 'const' declaration specifier
+*/
Index: lib/Sema/DeclSpec.cpp
===================================================================
--- lib/Sema/DeclSpec.cpp
+++ lib/Sema/DeclSpec.cpp
@@ -438,7 +438,7 @@
   if (TNew != TPrev)
     DiagID = diag::err_invalid_decl_spec_combination;
   else
-    DiagID = IsExtension ? diag::ext_duplicate_declspec :
+    DiagID = IsExtension ? diag::ext_warn_duplicate_declspec :
                            diag::warn_duplicate_declspec;
   return true;
 }
@@ -967,7 +967,7 @@
                                     unsigned &DiagID) {
   if (isModulePrivateSpecified()) {
     PrevSpec = "__module_private__";
-    DiagID = diag::ext_duplicate_declspec;
+    DiagID = diag::ext_warn_duplicate_declspec;
     return true;
   }
 
Index: lib/Parse/ParseDecl.cpp
===================================================================
--- lib/Parse/ParseDecl.cpp
+++ lib/Parse/ParseDecl.cpp
@@ -3838,7 +3838,8 @@
       assert(PrevSpec && "Method did not return previous specifier!");
       assert(DiagID);
 
-      if (DiagID == diag::ext_duplicate_declspec)
+      if (DiagID == diag::ext_duplicate_declspec ||
+          DiagID == diag::ext_warn_duplicate_declspec)
         Diag(Tok, DiagID)
           << PrevSpec << FixItHint::CreateRemoval(Tok.getLocation());
       else if (DiagID == diag::err_opencl_unknown_type_specifier) {
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -192,7 +192,9 @@
   "flexible array initialization is a GNU extension">, InGroup<GNUFlexibleArrayInitializer>;
 
 // Declarations.
-def ext_duplicate_declspec : ExtWarn<"duplicate '%0' declaration specifier">,
+def ext_duplicate_declspec : Extension<"duplicate '%0' declaration specifier">,
+  InGroup<DuplicateDeclSpecifier>;
+def ext_warn_duplicate_declspec : ExtWarn<"duplicate '%0' declaration specifier">,
   InGroup<DuplicateDeclSpecifier>;
 def warn_duplicate_declspec : Warning<"duplicate '%0' declaration specifier">,
   InGroup<DuplicateDeclSpecifier>;


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