Add a dummy NULL entry to method table; fixes problems with tests for NULL function pointers

Author: totalspectrum

Changelog.txt

@@ -1,5 +1,6 @@
 Version 7.0.1
 - Fixed incorrect casts of arrays
+- Put a dummy entry at the beginning of the method table, to represent NULL
 
 Version 7.0.0
 - Added Spin2 structures (basically small objects)

backends/asm/assemble_ir.c

@@ -561,7 +561,7 @@ OutputDataBlob(Flexbuf *fb, Flexbuf *databuf, Flexbuf *relocbuf, const char *sta
                 } else if (indexedFunc) {
                     if (sym->kind == SYM_FUNCTION) {
                         Function *F = (Function *)sym->v.ptr;
-                        indexForFunc = F->method_index - 1;
+                        indexForFunc = F->method_index;
                     } else {
                         indexForFunc = -1;
                     }

backends/asm/outasm.c

@@ -7293,6 +7293,8 @@ OutputAsmCode(const char *fname, Module *P, int outputMain)
         Function *LastG = NULL;
         Function *G;
         EmitLabel(&hubdata, method_table_label);
+        if (F)
+            EmitLong(&hubdata, 0); // dummy NULL entry
         while (F != LastG) {
             for (G = F; G->next_method != LastG; G = G->next_method) {
             }

backends/becommon.c

@@ -70,7 +70,7 @@ BuildMethodPointer(AST *ast)
     }
     // save off the current @ node
     if (IndexedMethodPtrs()) {
-        funcaddr = AstInteger(func->method_index-1);
+        funcaddr = AstInteger(func->method_index);
     } else {
         funcaddr = NewAST(AST_ADDROF, ast->left, ast->right);
     }

frontends/common.h

@@ -512,7 +512,7 @@ typedef struct funcdef {
 
     /* linked list of functions whose addresses are taken */
     /* used for building a jump table */
-    int method_index;            // index into jump table, +1
+    int method_index;            // index into jump table
     struct funcdef *next_method; // next in jump table
 } Function;