More work on call stack and trace

- Makes sure that all usages of `fh_call` are properly set up and push a
  new state onto the call stack. This needs some cleaning up yet.
  `fh_call` should manage the stack push and pop internally, taking
  whatever call metadata it needs as argument.
- Errors that occur in the execution of included files now properly
  display the script name.
- TODO: Errors while executing externally defined functions (in main or
  other) do not yet display the correct script name.
- Fixes a memory issue with the Function#apply implementation when the
  length of the argument array is 0.

src/eval.c

@@ -706,7 +706,7 @@ setup_call_env(js_val *ctx, js_val *this, js_val *func, js_args *args)
     fh_set(scope, func_node->sval, func);
 
   // Set up the (array-like) arguments object.
-  int i, arglen = ARGLEN(args);
+  unsigned i, arglen = ARGLEN(args);
   for (i = 0; i < arglen; i++)
     fh_set(arguments, JSNUMKEY(i)->string.ptr, ARG(args, i));
   fh_set_class(arguments, "Arguments");
@@ -832,7 +832,7 @@ new_exp(js_val *ctx, ast_node *exp)
     args = fh_new_args(0, 0, 0);
   }
 
-  eval_state *state= fh_new_state(exp->line, exp->column);
+  eval_state *state = fh_new_state(exp->line, exp->column);
   fh_push_state(state);
   state->construct = true;
 

src/flathead.c

@@ -198,27 +198,30 @@ fh_new_prop(js_prop_flags flags)
 void
 fh_pop_state()
 {
-  if (fh->statetrace) {
-    eval_state *pop = fh->statetrace;
-    fh->statetrace = pop->parent;
+  if (fh->callstack) {
+    eval_state *pop = fh->callstack;
+    fh->callstack = pop->parent;
     free(pop);
   }
 }
 
 void
 fh_push_state(eval_state *state)
 {
-  state->parent = fh->statetrace;
-  fh->statetrace = state;
+  state->parent = fh->callstack;
+  fh->callstack = state;
 }
 
 eval_state *
 fh_new_state(int line, int column)
 {
   eval_state *state = malloc(sizeof(eval_state));
+  memset(state, 0, sizeof(eval_state));
 
   state->line = line;
   state->column = column;
+  state->caller_info = NULL;
+  state->script_name = fh->script_name;
 
   state->ctx = NULL;
   state->this = NULL;
@@ -486,14 +489,18 @@ fh_error(eval_state *state, js_error_type type, const char *tpl, ...)
   fprintf(stderr, "\n");
 
   while (state != NULL) {
-    fprintf(stderr, "  at %s:%u:%u\n", 
-        fh->script_name, state->line, state->column);
+    if (state->caller_info)
+      fprintf(stderr, "  at %s (%s:%u:%u)\n", 
+          state->caller_info, state->script_name, state->line, state->column);
+    else
+      fprintf(stderr, "  at %s:%u:%u\n", 
+          state->script_name, state->line, state->column);
     if (!state->parent) break;
     state = state->parent;
   }
 
   if (fh->opt_interactive) {
-    fh->statetrace = NULL;
+    fh->callstack = NULL;
     longjmp(fh->jmpbuf, 1); 
   }
   exit(1);
@@ -580,7 +587,7 @@ fh_arg_len(js_args *args)
 
   // Although arrays can be up to 2^32 - 1 in length, we limit
   // the number of arguments to 2^16 - 1 (UINT_MAX).
-  unsigned int i = 0;
+  unsigned i = 0;
   while (i < UINT_MAX)
   {
     if (args->arg != NULL) i++;

src/flathead.h

@@ -149,11 +149,9 @@ typedef struct {
   bool opt_keep_history_file;
   const char *opt_history_filename;
 
-  const char *script_name;
-
   jmp_buf jmpbuf;                   // used to handle errors within REPL
-
-  struct eval_state *statetrace;
+  char *script_name;
+  struct eval_state *callstack;
 
   struct js_val *function_proto;    // cache prototype pointers
   struct js_val *object_proto;
@@ -167,6 +165,8 @@ typedef struct eval_state {
   bool construct;
   struct js_val *ctx;
   struct js_val *this;
+  char *caller_info;
+  char *script_name;
   struct eval_state *parent;
 } eval_state;
 
@@ -194,7 +194,7 @@ typedef struct {
 } js_number;
 
 typedef struct {
-  long length;
+  unsigned long length;
   char *ptr;
 } js_string;
 

src/grammar.y

@@ -100,6 +100,7 @@
   #define NEW_WITH(exp,stmt)         NEW_NODE(NODE_WITH_STMT,exp,stmt,0,0,0)
 
   void yyerror(const char *);
+  int yycolumn;
   int yydebug;
   int fh_get_input(char *, int);
   ast_node *root;
@@ -1193,6 +1194,10 @@ fh_eval_string(char *string, js_val *ctx)
   bool tmp = fh->opt_interactive;
   fh->opt_interactive = false;
 
+  eval_state *prior_state = fh_new_state(yylloc.first_line, yylloc.last_line);
+  yycolumn = 0;
+  yylineno = 0;
+
   YY_BUFFER_STATE buffer = yy_scan_string(string);
   yyparse();
 
@@ -1202,6 +1207,8 @@ fh_eval_string(char *string, js_val *ctx)
   js_val *res = fh_eval(ctx, root);
   yy_delete_buffer(buffer);
   fh->opt_interactive = tmp;
+  yylineno = prior_state->line;
+  yycolumn = prior_state->column;
   return res;
 }
 
@@ -1261,9 +1268,8 @@ main(int argc, char **argv)
         DEBUG(fh_eval_file(source, fh->global));
     }
   } 
-  else {
+  else
     fh_eval_file(source, fh->global);
-  }
 
   return 0;
 }

src/runtime/lib/Array.c

@@ -66,9 +66,10 @@ cmp(js_prop *a, js_prop *b)
 static int
 cmp_js(js_prop *a, js_prop *b)
 {
-  eval_state *state = js_cmp_state;
   js_args *args = fh_new_args(a->ptr, b->ptr, 0);
-  js_val *result = fh_call(state->ctx, JSUNDEF(), state, js_cmp_func, args);
+  eval_state *call_state = fh_new_state(js_cmp_state->line, js_cmp_state->column);
+  fh_push_state(call_state);
+  js_val *result = fh_call(js_cmp_state->ctx, JSUNDEF(), call_state, js_cmp_func, args);
   return TO_BOOL(result)->number.val > 0;
 }
 
@@ -565,11 +566,14 @@ arr_proto_filter(js_val *instance, js_args *args, eval_state *state)
 
   js_val *ikey, *jkey, *val, *result;
   js_args *cbargs;
+  eval_state *call_state;
   unsigned long i = 0, j = 0;
   for (; i < len; i++) {
     ikey = JSNUMKEY(i);
     val = fh_get(instance, ikey->string.ptr);
     cbargs = fh_new_args(val, JSNUM(i), instance);
+    call_state = fh_new_state(state->line, state->column);
+    fh_push_state(call_state);
     result = fh_call(state->ctx, this, state, callback, cbargs);
     if (TO_BOOL(result)->boolean.val) {
       jkey = JSNUMKEY(j++);
@@ -591,11 +595,14 @@ arr_proto_for_each(js_val *instance, js_args *args, eval_state *state)
 
   js_val *key, *val;
   js_args *cbargs;
+  eval_state *call_state;
   unsigned long i;
   for (i = 0; i < len; i++) {
     key = JSNUMKEY(i);
     val = fh_get(instance, key->string.ptr);
     cbargs = fh_new_args(val, JSNUM(i), instance);
+    call_state = fh_new_state(state->line, state->column);
+    fh_push_state(call_state);
     fh_call(state->ctx, this, state, callback, cbargs);
   }
 
@@ -612,11 +619,14 @@ arr_proto_every(js_val *instance, js_args *args, eval_state *state)
 
   js_val *key, *val, *result;
   js_args *cbargs;
+  eval_state *call_state;
   unsigned long i;
   for (i = 0; i < len; i++) {
     key = JSNUMKEY(i);
     val = fh_get(instance, key->string.ptr);
     cbargs = fh_new_args(val, JSNUM(i), instance);
+    call_state = fh_new_state(state->line, state->column);
+    fh_push_state(call_state);
     result = fh_call(state->ctx, this, state, callback, cbargs);
     if (!TO_BOOL(result)->boolean.val)
       return JSBOOL(0);
@@ -636,11 +646,14 @@ arr_proto_map(js_val *instance, js_args *args, eval_state *state)
 
   js_val *key, *val, *result;
   js_args *cbargs;
+  eval_state *call_state;
   unsigned long i;
   for (i = 0; i < len; i++) {
     key = JSNUMKEY(i);
     val = fh_get(instance, key->string.ptr);
     cbargs = fh_new_args(val, JSNUM(i), instance);
+    call_state = fh_new_state(state->line, state->column);
+    fh_push_state(call_state);
     result = fh_call(state->ctx, this, state, callback, cbargs);
     fh_set(map, key->string.ptr, result);
   }
@@ -659,11 +672,14 @@ arr_proto_some(js_val *instance, js_args *args, eval_state *state)
 
   js_val *key, *val, *result;
   js_args *cbargs;
+  eval_state *call_state;
   unsigned long i;
   for (i = 0; i < len; i++) {
     key = JSNUMKEY(i);
     val = fh_get(instance, key->string.ptr);
     cbargs = fh_new_args(val, JSNUM(i), instance);
+    call_state = fh_new_state(state->line, state->column);
+    fh_push_state(call_state);
     result = fh_call(state->ctx, this, state, callback, cbargs);
     if (TO_BOOL(result)->boolean.val)
       return JSBOOL(1);
@@ -693,10 +709,13 @@ arr_proto_reduce(js_val *instance, js_args *args, eval_state *state)
 
   js_val *key, *val;
   js_args *cbargs;
+  eval_state *call_state;
   for (; i < len; i++) {
     key = JSNUMKEY(i);
     val = fh_get(instance, key->string.ptr);
     cbargs = fh_new_args(reduction, val, JSNUM(i));
+    call_state = fh_new_state(state->line, state->column);
+    fh_push_state(call_state);
     reduction = fh_call(state->ctx, JSUNDEF(), state, callback, cbargs);
   }
 
@@ -733,9 +752,12 @@ arr_proto_reduce_right(js_val *instance, js_args *args, eval_state *state)
 
   js_val *val;
   js_args *cbargs;
+  eval_state *call_state;
   do {
     val = fh_get(instance, JSNUMKEY(i)->string.ptr);
     cbargs = fh_new_args(reduction, val, JSNUM(i));
+    call_state = fh_new_state(state->line, state->column);
+    fh_push_state(call_state);
     reduction = fh_call(state->ctx, JSUNDEF(), state, callback, cbargs);
   } while (i--);
 

src/runtime/lib/Function.c

@@ -46,11 +46,14 @@ func_proto_apply(js_val *instance, js_args *args, eval_state *state)
 {
   js_val *this = ARG(args, 0);
   js_val *arr = ARG(args, 1);
+
   js_args *func_args = malloc(sizeof(js_args));
   js_args *func_args_head = func_args;
+  func_args->arg = NULL;
+  func_args->next = NULL;
 
-  unsigned len = arr->object.length;
-  unsigned i;
+  unsigned long len = arr->object.length;
+  unsigned long i;
 
   for (i = 0; i < len; i++) {
     func_args->arg = fh_get(arr, JSNUMKEY(i)->string.ptr);
@@ -61,7 +64,9 @@ func_proto_apply(js_val *instance, js_args *args, eval_state *state)
     }
   }
 
-  return fh_call(state->ctx, this, state, instance, func_args_head);
+  eval_state *call_state = fh_new_state(state->line, state->column);
+  fh_push_state(call_state);
+  return fh_call(state->ctx, this, call_state, instance, func_args_head);
 }
 
 // Function.prototype.apply(thisValue[, arg1[, arg2[, ...]]])
@@ -89,6 +94,9 @@ func_proto_call(js_val *instance, js_args *args, eval_state *state)
   args->arg = NULL;
   if (args->next)
     args = args->next;
+
+  eval_state *call_state = fh_new_state(state->line, state->column);
+  fh_push_state(call_state);
   return fh_call(state->ctx, this, state, instance, args);
 }
 

src/runtime/lib/String.c

@@ -45,8 +45,9 @@ js_val *
 str_proto_char_at(js_val *instance, js_args *args, eval_state *state)
 {
   int index = TO_NUM(ARG(args, 0))->number.val;
+  int len = instance->string.length;
 
-  if (index < 0 || index >= instance->string.length)
+  if (index < 0 || index >= len)
     return JSSTR("");
   char *str = malloc(2);
   sprintf(str, "%c", instance->string.ptr[index]);

src/runtime/runtime.c

@@ -170,9 +170,12 @@ load_file(char *name)
   if (result != size)
     return -1;
 
+  char *prev_script = fh->script_name;
+  fh->script_name = name;
   fcontent[size] = '\0';
   fh_eval_string(fcontent, fh->global);
   free(fcontent);
+  fh->script_name = prev_script;
   return 0;
 }
 

test/test_function_global.js

@@ -97,7 +97,7 @@ test('Function#apply(thisValue[, argsArray])', function() {
   assertEquals(21, fib.apply(null, [8]));
   assertEquals(21, fib.apply(undefined, [8]));
   assertEquals(24, getX.apply(thisValue, []));
-  assertEquals(99, getY.call(thisValue));
+  assertEquals(99, getY.apply(thisValue));
   assertThis.apply(this, [this]);
   assertThis.apply(thisValue, [thisValue]);
 });