WIP: Fixes GC bugs, adds additional GC profile/debug tools

- First steps toward a real garbage collector. Fixes some big issues
  with mark and sweep. There are still some other GC issues that crop up
  when it's run many times, particularly with large callstacks caused by
  recursion. I'm working on additional improvements.

Makefile

@@ -15,7 +15,7 @@
 # OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 CC = gcc
-CFLAGS = -Wall -Wextra -Wno-unused-parameter -O3 -std=c99 -pedantic -D_XOPEN_SOURCE
+CFLAGS = -dD -Wall -Wextra -Wno-unused-parameter -O3 -std=c99 -pedantic -D_XOPEN_SOURCE
 
 YACC = bison
 YACC_FLAGS = -y -d -t -v
@@ -28,8 +28,9 @@ OBJ_FILES = y.tab.o lex.yy.o src/eval.o src/str.o src/regexp.o src/cli.o \
 src/nodes.o src/args.o src/flathead.o src/debug.o src/gc.o src/props.o \
 src/runtime/runtime.o src/runtime/lib/Math.o src/runtime/lib/RegExp.o \
 src/runtime/lib/Error.o src/runtime/lib/String.o src/runtime/lib/console.o \
-src/runtime/lib/Function.o src/runtime/lib/Object.o src/runtime/lib/Boolean.o \
-src/runtime/lib/Number.o src/runtime/lib/Date.o src/runtime/lib/Array.o
+src/runtime/lib/gc.o src/runtime/lib/Function.o src/runtime/lib/Object.o \
+src/runtime/lib/Boolean.o src/runtime/lib/Number.o src/runtime/lib/Date.o \
+src/runtime/lib/Array.o
 
 OUT_FILE = bin/flat
 YACC_FILE = src/grammar.y
@@ -76,8 +77,8 @@ all: default
 debug: CFLAGS += -g -O0
 debug: clean default
 
-malloc-debug: CC = gcc-4.7
-malloc-debug: LIBS += -lefence
+malloc-debug: CC = gcc-4.9
+malloc-debug: LIBS += -lduma
 malloc-debug: debug
 
 

src/debug.c

@@ -131,7 +131,7 @@ fh_debug(FILE *stream, js_val *val, int indent, bool newline)
       else if (IS_FUNC(val))
         cfprintf(stream, ANSI_BLUE, "[Function]");
       else if (IS_DATE(val))
-        fh_debug(stream, fh_to_primitive(val, 0), indent, false);
+        fprintf(stream, "[Date %ld]", (long)val->object.primitive->number.val);
       else
         debug_obj(stream, val, indent, false);
       break;

src/eval.c

@@ -88,6 +88,7 @@ member_exp(js_val *ctx, ast_node *member)
     int i = member->e1->val, len = parent->string.length;
     if (i < len && i >= 0) {
       char *str = malloc(sizeof(char) + 1);
+      str[1] = '\0';
       sprintf(str, "%c", parent->string.ptr[i]);
       return JSSTR(str);
     }
@@ -466,10 +467,10 @@ switch_stmt(js_val *ctx, ast_node *node)
   js_val *val, *result, *test = fh_eval(ctx, node->e1);
 
   ast_node *current,
-       *caseblock = node->e2,
-       *clauses_a = caseblock->e1, 
-       *defaultclause = caseblock->e2, 
-       *clauses_b = caseblock->e3;
+           *caseblock = node->e2,
+           *clauses_a = caseblock->e1, 
+           *defaultclause = caseblock->e2, 
+           *clauses_b = caseblock->e3;
 
   bool matched = false;
 
@@ -806,6 +807,7 @@ call(js_val *ctx, js_val *this, js_val *func, eval_state *state, js_args *args)
     state->caller_info = "(anonymous function)";
 
   js_val *func_scope = setup_call_env(ctx, this, func, args);
+  state->scope = func_scope;
   return fh_eval(func_scope, func->object.node->e2);
 }
 

src/flathead.c

@@ -40,6 +40,7 @@ fh_new_val(js_type type)
   val->type = type;
   val->signal = S_NONE;
   val->proto = NULL;
+  val->marked = false;
 
   return val;
 }
@@ -71,6 +72,7 @@ fh_new_string(char *x)
   js_val *val = fh_new_val(T_STRING);
 
   val->string.ptr = malloc((strlen(x) + 1) * sizeof(char));
+  val->string.ptr[strlen(x)] = '\0';
   strcpy(val->string.ptr, x);
   fh_set_len(val, strlen(x));
   val->proto = fh_try_get_proto("String");
@@ -99,6 +101,11 @@ fh_new_object()
   val->object.extensible = false;
   val->object.parent = NULL;
   val->object.primitive = NULL;
+  val->object.bound_this = NULL;
+  val->object.bound_args = NULL;
+  val->object.scope = NULL;
+  val->object.instance = NULL;
+  val->object.node = NULL;
   val->proto = fh->object_proto;
 
   return val;
@@ -129,6 +136,7 @@ fh_new_function(struct ast_node *node)
   fh_set(val, "caller", JSNULL());
 
   val->object.native = false;
+  val->object.provide_this = false;
   val->object.generator = false;
   val->object.node = node;
   val->object.scope = NULL;
@@ -198,6 +206,7 @@ fh_new_error(char *name, const char *tpl, ...)
   va_end(ap);
 
   char *msg = malloc(size + 1);
+  msg[size] = '\0';
 
   // Now build the error message
   va_start(ap, tpl);
@@ -253,6 +262,7 @@ fh_new_state(int line, int column)
 
   state->ctx = NULL;
   state->this = NULL;
+  state->scope = NULL;
   state->parent = NULL;
   state->construct = false;
   state->catch = false;
@@ -275,6 +285,7 @@ fh_new_global_state()
   state->global = NULL;
   state->function_proto = NULL;
   state->object_proto = NULL;
+  state->callstack = NULL;
 
   state->script_name = "main";
 
@@ -414,6 +425,7 @@ fh_to_string(js_val *val)
       fmt = "%g";
     int size = snprintf(NULL, 0, fmt, val->number.val) + 1;
     char *num = malloc(size);
+    num[size] = '\0';
     snprintf(num, size, fmt, val->number.val);
     return JSSTR(num);
   }
@@ -428,17 +440,23 @@ fh_to_object(js_val *val)
 {
   if (IS_UNDEF(val) || IS_NULL(val))
     fh_throw(NULL, fh_new_error(E_TYPE, "cannot convert %s to object", fh_typeof(val)));
-  if (IS_OBJ(val)) 
+  if (IS_OBJ(val))
     return val;
 
   js_val *obj = JSOBJ();
   obj->object.primitive = val;
-  if (IS_BOOL(val))
+  if (IS_BOOL(val)) {
     fh_set_class(obj, "Boolean");
-  if (IS_NUM(val))
+    obj->proto = fh_try_get_proto("Boolean");
+  }
+  if (IS_NUM(val)) {
     fh_set_class(obj, "Number");
-  if (IS_STR(val))
+    obj->proto = fh_try_get_proto("Number");
+  }
+  if (IS_STR(val)) {
     fh_set_class(obj, "String");
+    obj->proto = fh_try_get_proto("String");
+  }
   return obj;
 }
 
@@ -558,6 +576,12 @@ fh_has_instance(js_val *func, js_val *val)
   return JSBOOL(0);
 }
 
+js_val *
+fh_implicit_this_value(js_val *obj)
+{
+  return obj->object.provide_this ? obj->object.bound_this : JSUNDEF();
+}
+
 js_val *
 fh_has_property(js_val *obj, char *prop)
 {
@@ -568,6 +592,14 @@ fh_has_property(js_val *obj, char *prop)
 js_val *
 fh_try_get_proto(char *type)
 {
+  // Try to avoid a lookup.
+  if (STREQ(type, "Function") && fh->function_proto)
+    return fh->function_proto;
+  if (STREQ(type, "Object") && fh->object_proto)
+    return fh->object_proto;
+  if (STREQ(type, "Array") && fh->array_proto)
+    return fh->array_proto;
+
   js_val *global = fh->global;
   if (global != NULL) {
     js_val *obj = fh_get(global, type);

src/flathead.h

@@ -167,6 +167,7 @@ typedef struct eval_state {
   bool catch;
   struct js_val *ctx;
   struct js_val *this;
+  struct js_val *scope;
   jmp_buf jmp;
   struct eval_state *parent;
 } eval_state;
@@ -206,6 +207,7 @@ typedef struct js_val * (js_native_function)(struct js_val *, struct js_args *,
 typedef struct {
   bool native;
   bool generator;
+  bool provide_this;
   bool extensible;            // [[Extensible]]
   char class[10];             // [[Class]]
   struct js_val *primitive;   // [[PrimitiveValue]]
@@ -232,6 +234,7 @@ typedef struct js_val {
   ctl_signal signal;
   struct js_val *proto;
   bool marked;
+  bool flagged; 
   js_prop *map;
 } js_val;
 
@@ -269,6 +272,7 @@ js_val * fh_to_object(js_val *);
 js_val * fh_cast(js_val *, js_type);
 
 js_val * fh_has_instance(js_val *, js_val *);
+js_val * fh_implicit_this_value(js_val *obj);
 js_val * fh_has_property(js_val *, char *);
 char * fh_typeof(js_val *);
 void fh_set_len(js_val *, unsigned long);