[PATCH] D52248: [SEMA] ignore duplicate declaration specifiers from typeof exprs

[Nick Desaulniers via Phabricator via cfe-commits]

nickdesaulniers updated this revision to Diff 166578.
nickdesaulniers marked an inline comment as done.
nickdesaulniers added a comment.

- also run test on gnu99+


Repository:
  rC Clang

https://reviews.llvm.org/D52248

Files:
  lib/Sema/SemaType.cpp
  test/Sema/gnu89-const.c


Index: test/Sema/gnu89-const.c
===================================================================
--- /dev/null
+++ test/Sema/gnu89-const.c
@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 %s -std=gnu89 -fsyntax-only 2>&1 | FileCheck -check-prefix=CHECK-ABSTRUSE %s
+// RUN: %clang_cc1 %s -std=gnu89 -pedantic -fsyntax-only 2>&1 | FileCheck -check-prefix=CHECK-GNU89-PEDANTIC %s
+// RUN: %clang_cc1 %s -std=gnu99 -fsyntax-only 2>&1 | FileCheck -check-prefix=CHECK-ABSTRUSE %s
+// RUN: %clang_cc1 %s -std=gnu99 -pedantic -fsyntax-only 2>&1 | FileCheck -check-prefix=CHECK-ABSTRUSE %s
+// RUN: %clang_cc1 %s -std=gnu11 -fsyntax-only 2>&1 | FileCheck -check-prefix=CHECK-ABSTRUSE %s
+// RUN: %clang_cc1 %s -std=gnu11 -pedantic -fsyntax-only 2>&1 | FileCheck -check-prefix=CHECK-ABSTRUSE %s
+// RUN: %clang_cc1 %s -std=gnu17 -fsyntax-only 2>&1 | FileCheck -check-prefix=CHECK-ABSTRUSE %s
+// RUN: %clang_cc1 %s -std=gnu17 -pedantic -fsyntax-only 2>&1 | FileCheck -check-prefix=CHECK-ABSTRUSE %s
+
+// Do not warn about duplicate const declaration specifier as the result of
+// typeof in gnu89, unless -pedantic was specified. Do not warn in gnu99+, even
+// with -pedantic.
+const int c_i;
+const typeof(c_i) c_i2;
+// CHECK-GNU89-PEDANTIC: 14:7: warning: extension used
+// CHECK-GNU89-PEDANTIC: 14:1: warning: duplicate 'const' declaration specifier
+// CHECK-ABSTRUSE-NOT: 14:1: warning: duplicate 'const' declaration specifier
+
+const const int c_i3;
+// CHECK: 19:7: warning: duplicate 'const' declaration specifier
+
+typedef const int t;
+const t c_i4;
+// CHECK: 23:1: warning: duplicate 'const' declaration specifier
Index: lib/Sema/SemaType.cpp
===================================================================
--- lib/Sema/SemaType.cpp
+++ lib/Sema/SemaType.cpp
@@ -1679,8 +1679,13 @@
     // C90 6.5.3 constraints: "The same type qualifier shall not appear more
     // than once in the same specifier-list or qualifier-list, either directly
     // or via one or more typedefs."
-    if (!S.getLangOpts().C99 && !S.getLangOpts().CPlusPlus
-        && TypeQuals & Result.getCVRQualifiers()) {
+    //
+    // Not checked for gnu89 if the TST is from a typeof expression and
+    // -pedantic was not set.
+    if (!S.getLangOpts().C99 && !S.getLangOpts().CPlusPlus &&
+        TypeQuals & Result.getCVRQualifiers() &&
+        !(S.getLangOpts().GNUMode && !S.Diags.getDiagnosticOptions().Pedantic &&
+          DS.getTypeSpecType() == DeclSpec::TST_typeofExpr)) {
       if (TypeQuals & DeclSpec::TQ_const && Result.isConstQualified()) {
         S.Diag(DS.getConstSpecLoc(), diag::ext_duplicate_declspec)
           << "const";


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