Add a warning if a function returning something does not contain a return

statement.

git-svn-id: svn://svn.cc65.org/cc65/trunk@4095 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/src/cc65/function.c b/src/cc65/function.c
index b8f1cb7533f535c8a37cc4dd0185470f79cc13c5..7e2e9145f3a14754397be1129b713d2bed11fdfc 100644 (file)
--- a/src/cc65/function.c
+++ b/src/cc65/function.c
@@ -6,10 +6,10 @@
 /*                                                                           */
 /*                                                                           */
 /*                                                                           */
-/* (C) 2000-2008 Ullrich von Bassewitz                                       */
-/*               Roemerstrasse 52                                            */
-/*               D-70794 Filderstadt                                         */
-/* EMail:        uz@cc65.org                                                 */
+/* (C) 2000-2009, Ullrich von Bassewitz                                      */
+/*                Roemerstrasse 52                                           */
+/*                D-70794 Filderstadt                                        */
+/* EMail:         uz@cc65.org                                                */
 /*                                                                           */
 /*                                                                           */
 /* This software is provided 'as-is', without any expressed or implied       */
@@ -71,6 +71,7 @@ struct Function {
     unsigned           RetLab;         /* Return code label */
     int                        TopLevelSP;     /* SP at function top level */
     unsigned            RegOffs;        /* Register variable space offset */
+    int                 HasRetStmt;     /* Function has a return statement */
 };
 
 /* Pointer to current function */
@@ -79,7 +80,7 @@ Function* CurrentFunc = 0;
 
 
 /*****************************************************************************/
-/*                Subroutines working with struct Function                  */
+/*                        Subroutines working with struct Function                  */
 /*****************************************************************************/
 
 
@@ -98,6 +99,7 @@ static Function* NewFunction (struct SymEntry* Sym)
     F->RetLab    = GetLocalLabel ();
     F->TopLevelSP = 0;
     F->RegOffs    = RegisterSpace;
+    F->HasRetStmt = 0;
 
     /* Return the new structure */
     return F;
@@ -153,6 +155,14 @@ int F_HasVoidReturn (const Function* F)
 
 
 
+void F_HasReturn (Function* F)
+/* Mark the function as having a return statement */
+{
+    F->HasRetStmt = 1;
+}
+
+
+
 int F_IsVariadic (const Function* F)
 /* Return true if this is a variadic function */
 {
@@ -335,7 +345,6 @@ static void F_RestoreRegVars (Function* F)
 void NewFunc (SymEntry* Func)
 /* Parse argument declarations and function body. */
 {
-    int HadReturn;
     SymEntry* Param;
 
     /* Get the function descriptor from the function entry */
@@ -467,13 +476,15 @@ void NewFunc (SymEntry* Func)
     CurrentFunc->TopLevelSP = StackPtr;
 
     /* Now process statements in this block */
-    HadReturn = 0;
-    while (CurTok.Tok != TOK_RCURLY) {
-       if (CurTok.Tok != TOK_CEOF) {
-           HadReturn = Statement (0);
-       } else {
-           break;
-       }
+    while (CurTok.Tok != TOK_RCURLY && CurTok.Tok != TOK_CEOF) {
+        Statement (0);
+    }
+
+    /* If this is not a void function, output a warning if we didn't see a
+     * return statement.
+     */
+    if (!F_HasVoidReturn (CurrentFunc) && !CurrentFunc->HasRetStmt) {
+        Warning ("Control reaches end of non-void function");
     }
 
     /* Output the function exit code label */

diff --git a/src/cc65/function.h b/src/cc65/function.h
index d56d30757645ee45b84e27ab1fcb4eb49f4f91a9..d827cba6af9104d9e40318de3f3e323c1c20f4d9 100644 (file)
--- a/src/cc65/function.h
+++ b/src/cc65/function.h
@@ -6,10 +6,10 @@
 /*                                                                           */
 /*                                                                           */
 /*                                                                           */
-/* (C) 1998-2006 Ullrich von Bassewitz                                       */
-/*               Römerstrasse 52                                             */
-/*               D-70794 Filderstadt                                         */
-/* EMail:        uz@cc65.org                                                 */
+/* (C) 1998-2009, Ullrich von Bassewitz                                      */
+/*                Roemerstrasse 52                                           */
+/*                D-70794 Filderstadt                                        */
+/* EMail:         uz@cc65.org                                                */
 /*                                                                           */
 /*                                                                           */
 /* This software is provided 'as-is', without any expressed or implied       */
@@ -73,6 +73,9 @@ Type* F_GetReturnType (Function* F);
 int F_HasVoidReturn (const Function* F);
 /* Return true if the function does not have a return value */
 
+void F_HasReturn (Function* F);
+/* Mark the function as having a return statement */
+
 int F_IsVariadic (const Function* F);
 /* Return true if this is a variadic function */
 

diff --git a/src/cc65/stmt.c b/src/cc65/stmt.c
index ef150fad598b49286196a4e6eb0318d09ba53ab6..b9b258aa09e365741b5263cf3d1e24d9e1715dfe 100644 (file)
--- a/src/cc65/stmt.c
+++ b/src/cc65/stmt.c
@@ -6,10 +6,10 @@
 /*                                                                           */
 /*                                                                           */
 /*                                                                           */
-/* (C) 1998-2008 Ullrich von Bassewitz                                       */
-/*               Roemerstrasse 52                                            */
-/*               D-70794 Filderstadt                                         */
-/* EMail:        uz@cc65.org                                                 */
+/* (C) 1998-2009, Ullrich von Bassewitz                                      */
+/*                Roemerstrasse 52                                           */
+/*                D-70794 Filderstadt                                        */
+/* EMail:         uz@cc65.org                                                */
 /*                                                                           */
 /*                                                                           */
 /* This software is provided 'as-is', without any expressed or implied       */
@@ -292,17 +292,16 @@ static void ReturnStatement (void)
     NextToken ();
     if (CurTok.Tok != TOK_SEMI) {
 
-        /* Check if the function has a return value declared */
-               if (F_HasVoidReturn (CurrentFunc)) {
-                   Error ("Returning a value in function with return type void");
-               }
-
        /* Evaluate the return expression */
        hie0 (&Expr);
 
-       /* Ignore the return expression if the function returns void */
-       if (!F_HasVoidReturn (CurrentFunc)) {
-
+        /* If we return something in a void function, print an error and
+         * ignore the value. Otherwise convert the value to the type of the
+         * return.
+         */
+               if (F_HasVoidReturn (CurrentFunc)) {
+                   Error ("Returning a value in function with return type void");
+               } else {
            /* Convert the return value to the type of the function result */
            TypeConversion (&Expr, F_GetReturnType (CurrentFunc));
 
@@ -314,6 +313,9 @@ static void ReturnStatement (void)
        Error ("Function `%s' must return a value", F_GetFuncName (CurrentFunc));
     }
 
+    /* Mark the function as having a return statement */
+    F_HasReturn (CurrentFunc);
+
     /* Cleanup the stack in case we're inside a block with locals */
     g_space (StackPtr - F_GetTopLevelSP (CurrentFunc));