From a1fcbadf4f930c22bb171fb90ed886f5f359d010 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Thu, 18 Dec 2008 06:50:14 +0000
Subject: [PATCH] Clean up the C89/C++ warnings about C99 array features to not
 emit duplicate diags (some in parser and some in sema) and to warn about use
 of typequals in array sizes.  This implements PR2759.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@61197 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Basic/DiagnosticKinds.def |  2 +-
 lib/Parse/ParseDecl.cpp                 | 17 +++++------------
 lib/Sema/SemaType.cpp                   | 12 +++++++-----
 test/Sema/c89.c                         |  7 +++++++
 4 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/include/clang/Basic/DiagnosticKinds.def b/include/clang/Basic/DiagnosticKinds.def
index 38d084fc99..39464efd6a 100644
--- a/include/clang/Basic/DiagnosticKinds.def
+++ b/include/clang/Basic/DiagnosticKinds.def
@@ -310,7 +310,7 @@ DIAG(warn_enum_value_overflow, WARNING,
 DIAG(ext_ident_list_in_param, EXTENSION,
      "type-less parameter names in function declaration")
 DIAG(ext_c99_array_usage, EXTENSION,
-     "use of C99-specific array features")
+     "use of C99-specific array features, accepted as an extension")
 DIAG(ext_c99_variable_decl_in_for_loop, EXTENSION,
      "variable declaration in for loop is a C99-specific feature")
 DIAG(ext_c99_compound_literal, EXTENSION,
diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index 1a8e5d9f95..e31b87bd43 100644
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -1283,7 +1283,7 @@ void Parser::ParseTypeQualifierListOpt(DeclSpec &DS) {
       DS.AddAttributes(ParseAttributes());
       continue; // do *not* consume the next token!
     }
-    
+
     // If the specifier combination wasn't legal, issue a diagnostic.
     if (isInvalid) {
       assert(PrevSpec && "Method did not return previous specifier!");
@@ -1943,6 +1943,7 @@ void Parser::ParseBracketDeclarator(Declarator &D) {
     StaticLoc = ConsumeToken();
   
   // If there is a type-qualifier-list, read it now.
+  // Type qualifiers in an array subscript are a C99 feature.
   DeclSpec DS;
   ParseTypeQualifierListOpt(DS);
   
@@ -1962,9 +1963,10 @@ void Parser::ParseBracketDeclarator(Declarator &D) {
   if (Tok.is(tok::star) && GetLookAheadToken(1).is(tok::r_square)) {
     ConsumeToken();  // Eat the '*'.
 
-    if (StaticLoc.isValid())
+    if (StaticLoc.isValid()) {
       Diag(StaticLoc, diag::err_unspecified_vla_size_with_static);
-    StaticLoc = SourceLocation();  // Drop the static.
+      StaticLoc = SourceLocation();  // Drop the static.
+    }
     isStar = true;
   } else if (Tok.isNot(tok::r_square)) {
     // Parse the assignment-expression now.
@@ -1980,15 +1982,6 @@ void Parser::ParseBracketDeclarator(Declarator &D) {
   
   MatchRHSPunctuation(tok::r_square, StartLoc);
     
-  // If C99 isn't enabled, emit an ext-warn if the arg list wasn't empty and if
-  // it was not a constant expression.
-  if (!getLang().C99) {
-    // TODO: check C90 array constant exprness.
-    if (isStar || StaticLoc.isValid() ||
-        0/*TODO: NumElts is not a C90 constantexpr */)
-      Diag(StartLoc, diag::ext_c99_array_usage);
-  }
-
   // Remember that we parsed a pointer type, and remember the type-quals.
   D.AddTypeInfo(DeclaratorChunk::getArray(DS.getTypeQualifiers(),
                                           StaticLoc.isValid(), isStar,
diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index 3f911f5b0c..a6441c8d70 100644
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -416,11 +416,13 @@ QualType Sema::GetTypeForDeclarator(Declarator &D, Scope *S, unsigned Skip) {
         T = Context.getConstantArrayType(T, ConstVal, ASM, ATI.TypeQuals);
       }
       // If this is not C99, extwarn about VLA's and C99 array size modifiers.
-      if (!getLangOptions().C99 &&
-          (ASM != ArrayType::Normal ||
-           (ArraySize && !ArraySize->isValueDependent() && 
-            !ArraySize->isIntegerConstantExpr(Context))))
-        Diag(D.getIdentifierLoc(), diag::ext_vla);
+      if (!getLangOptions().C99) {
+        if (ArraySize && !ArraySize->isValueDependent() && 
+            !ArraySize->isIntegerConstantExpr(Context))
+          Diag(D.getIdentifierLoc(), diag::ext_vla);
+        else if (ASM != ArrayType::Normal || ATI.TypeQuals != 0)
+          Diag(D.getIdentifierLoc(), diag::ext_c99_array_usage);
+      }
       break;
     }
     case DeclaratorChunk::Function:
diff --git a/test/Sema/c89.c b/test/Sema/c89.c
index b1780e9161..0c7496ac7a 100644
--- a/test/Sema/c89.c
+++ b/test/Sema/c89.c
@@ -60,3 +60,10 @@ void foo(T); /* typedef for void is allowed */
 
 void foo(void) {}
 
+/* PR2759 */
+void test10 (int x[*]); /* expected-warning {{use of C99-specific array features}} */
+void test11 (int x[static 4]); /* expected-warning {{use of C99-specific array features}} */
+
+void test12 (int x[const 4]) { /* expected-warning {{use of C99-specific array features}} */
+  int Y[x[1]]; /* expected-warning {{variable length arrays are a C99 feature, accepted as an extension}} */
+}
-- 
2.40.0