Added a new CS_RangeHasLabel function

git-svn-id: svn://svn.cc65.org/cc65/trunk@1058 b7a2c559-68d2-44c3-8de9-860c34a00d81

src/cc65/codeseg.c

@@ -725,6 +725,36 @@ unsigned CS_GetEntryIndex (CodeSeg* S, struct CodeEntry* E)
 
 
 
+int CS_RangeHasLabel (CodeSeg* S, unsigned Start, unsigned Count)
+/* Return true if any of the code entries in the given range has a label
+ * attached. If the code segment does not span the given range, check the
+ * possible span instead.
+ */
+{
+    unsigned EntryCount = CS_GetEntryCount(S);
+
+    /* Adjust count. We expect at least Start to be valid. */
+    CHECK (Start < EntryCount);
+    if (Start + Count > EntryCount) {
+    	Count = EntryCount - Start;
+    }
+
+    /* Check each entry. Since we have validated the index above, we may
+     * use the unchecked access function in the loop which is faster.
+     */
+    while (Count--) {
+	const CodeEntry* E = CollAtUnchecked (&S->Entries, Start++);
+	if (CE_HasLabel (E)) {
+	    return 1;
+	}
+    }
+    
+    /* No label in the complete range */
+    return 0;
+}
+
+
+
 CodeLabel* CS_AddLabel (CodeSeg* S, const char* Name)
 /* Add a code label for the next instruction to follow */
 {
@@ -806,6 +836,7 @@ void CS_MergeLabels (CodeSeg* S)
  */
 {
     unsigned I;
+    unsigned J;
 
     /* First, remove all labels from the label symbol table that don't have an
      * owner (this means that they are actually external labels but we didn't
@@ -817,12 +848,25 @@ void CS_MergeLabels (CodeSeg* S)
       	CodeLabel** L = &S->LabelHash[I];
       	while (*L) {
       	    if ((*L)->Owner == 0) {
+
 		/* The label does not have an owner, remove it from the chain */
       	 	CodeLabel* X = *L;
        	       	*L = X->Next;
+
+		/* Cleanup any entries jumping to this label */
+	       	for (J = 0; J < CL_GetRefCount (X); ++J) {
+		    /* Get the entry referencing this label */
+		    CodeEntry* E = CL_GetRef (X, J);
+		    /* And remove the reference */
+		    E->JumpTo = 0;
+		}
+
+		/* Print some debugging output */
       		if (Debug) {
       		    printf ("Removing unused global label `%s'", X->Name);
       		}
+
+		/* And free the label */
       	 	FreeCodeLabel (X);
       	    } else {
       	 	/* Label is owned, point to next code label pointer */

src/cc65/codeseg.h

@@ -171,6 +171,12 @@ int CS_GetEntries (CodeSeg* S, struct CodeEntry** List,
 unsigned CS_GetEntryIndex (CodeSeg* S, struct CodeEntry* E);
 /* Return the index of a code entry */
 
+int CS_RangeHasLabel (CodeSeg* S, unsigned Start, unsigned Count);
+/* Return true if any of the code entries in the given range has a label
+ * attached. If the code segment does not span the given range, check the
+ * possible span instead.
+ */
+
 CodeLabel* CS_AddLabel (CodeSeg* S, const char* Name);
 /* Add a code label for the next instruction to follow */