[cfe-dev] Statement scoping issue

[Neil Booth]

Neil Booth wrote:-

> C99 scoping seems to work apart from this, whose return b is invalid
> as there is no "b" in scope:
> 
> int f (int z)
> {
>    if (z > sizeof (enum {a, b}))
>       return a;
>    return b;
> }

Fixed below.

Neil.
-------------- next part --------------
Index: test/Parser/if-scope-c90.c
===================================================================
--- test/Parser/if-scope-c90.c	(revision 0)
+++ test/Parser/if-scope-c90.c	(revision 0)
@@ -0,0 +1,8 @@
+// RUN: clang -parse-ast-check --std=c90 %s
+
+int f (int z)
+{ 
+   if (z > sizeof (enum {a, b}))
+      return a;
+   return b;
+} 
Index: test/Parser/if-scope-c99.c
===================================================================
--- test/Parser/if-scope-c99.c	(revision 0)
+++ test/Parser/if-scope-c99.c	(revision 0)
@@ -0,0 +1,8 @@
+// RUN: clang -parse-ast-check --std=c99 %s
+
+int f (int z)
+{ 
+   if (z > sizeof (enum {a, b}))
+      return a;
+   return b; // expected-error{{use of undeclared identifier}}
+}
Index: Parse/ParseStmt.cpp
===================================================================
--- Parse/ParseStmt.cpp	(revision 41464)
+++ Parse/ParseStmt.cpp	(working copy)
@@ -427,10 +427,17 @@
     return true;
   }
   
+  // C99 6.8.4p3 - In C99, the if statement is a block.  This is not
+  // the case for C90.
+  if (getLang().C99)
+    EnterScope(Scope::DeclScope);
+
   // Parse the condition.
   ExprResult CondExp = ParseSimpleParenExpression();
   if (CondExp.isInvalid) {
     SkipUntil(tok::semi);
+    if (getLang().C99)
+      ExitScope();
     return true;
   }
   
@@ -472,6 +479,9 @@
       ElseStmt = Actions.ParseNullStmt(ElseLoc);
   }
   
+  if (getLang().C99)
+    ExitScope();
+
   return Actions.ParseIfStmt(IfLoc, CondExp.Val, CondStmt.Val,
                              ElseLoc, ElseStmt.Val);
 }
@@ -488,10 +498,14 @@
     SkipUntil(tok::semi);
     return true;
   }
-  
-  // Start the switch scope.
-  EnterScope(Scope::BreakScope|Scope::DeclScope);
 
+  // C99 6.8.4p3 - In C99, the switch statement is a block.  This is
+  // not the case for C90.  Start the switch scope.
+  if (getLang().C99)
+    EnterScope(Scope::BreakScope|Scope::DeclScope);
+  else
+    EnterScope(Scope::BreakScope);
+
   // Parse the condition.
   ExprResult Cond = ParseSimpleParenExpression();
   
@@ -538,8 +552,12 @@
     return true;
   }
   
-  // Start the loop scope.
-  EnterScope(Scope::BreakScope | Scope::ContinueScope | Scope::DeclScope);
+  // C99 6.8.5p5 - In C99, the while statement is a block.  This is not
+  // the case for C90.  Start the loop scope.
+  if (getLang().C99)
+    EnterScope(Scope::BreakScope | Scope::ContinueScope | Scope::DeclScope);
+  else
+    EnterScope(Scope::BreakScope | Scope::ContinueScope);
 
   // Parse the condition.
   ExprResult Cond = ParseSimpleParenExpression();
@@ -571,8 +589,12 @@
   assert(Tok.getKind() == tok::kw_do && "Not a do stmt!");
   SourceLocation DoLoc = ConsumeToken();  // eat the 'do'.
   
-  // Start the loop scope.
-  EnterScope(Scope::BreakScope | Scope::ContinueScope | Scope::DeclScope);
+  // C99 6.8.5p5 - In C99, the do statement is a block.  This is not
+  // the case for C90.  Start the loop scope.
+  if (getLang().C99)
+    EnterScope(Scope::BreakScope | Scope::ContinueScope | Scope::DeclScope);
+  else
+    EnterScope(Scope::BreakScope | Scope::ContinueScope);
 
   // C99 6.8.5p5 - In C99, the body of the if statement is a scope, even if
   // there is no compound stmt.  C90 does not have this clause. We only do this
@@ -626,7 +648,12 @@
     return true;
   }
   
-  EnterScope(Scope::BreakScope | Scope::ContinueScope | Scope::DeclScope);
+  // C99 6.8.5p5 - In C99, the for statement is a block.  This is not
+  // the case for C90.  Start the loop scope.
+  if (getLang().C99)
+    EnterScope(Scope::BreakScope | Scope::ContinueScope | Scope::DeclScope);
+  else
+    EnterScope(Scope::BreakScope | Scope::ContinueScope);
 
   SourceLocation LParenLoc = ConsumeParen();
   ExprResult Value;