binop infer

global.c

 	return -EINVAL;
 }
 
+/* :binop */
+
+static int global_binop_type_infer(const struct func *func, struct node *n)
+{
+	struct node *lval, *rval;
+
+	lval = n->expr.args;
+	rval = lval->next;
+
+	if (n->sym->type || !lval->sym->type || !rval->sym->type)
+		return 0;
+
+	if (type_equal(lval->sym->type, rval->sym->type)) {
+		n->sym->type = lval->sym->type;
+		return 0;
+	}
+
+	/* TODO handle integer promotion */
+	return 0;
+}
 
 /* pid */
 
 	{
 		.name = "+",
 		.type = &t_2args_func,
+		.type_infer = global_binop_type_infer,
 	},
 	{
 		.name = "-",
 		.type = &t_2args_func,
+		.type_infer = global_binop_type_infer,
 	},
 	
 	{

kprobe.c

 
 #include <linux/ptrace.h>
 
+#include "func.h"
+#include "node.h"
 #include "ply.h"
+#include "sym.h"
+#include "type.h"
 
 struct kprobe {
 };
 /* 	return 0; */
 /* } */
 
-/* static inline int is_arg(const char *name) */
-/* { */
-/* 	return (strstr(name, "arg") == name) */
-/* 		&& (strlen(name) == 4) */
-/* 		&& (name[3] >= '0' && name[3] <= '9'); */
-/* } */
+static inline int is_arg(const char *name)
+{
+	return (strstr(name, "arg") == name)
+		&& (strlen(name) == 4)
+		&& (name[3] >= '0' && name[3] <= '9');
+}
 
 /* static int kprobe_rewrite_arg(prog_t *prog, node_t *n) */
 /* { */
 /* 	return sym_add(prog->locals, n->ident, t, &n->sym); */
 /* } */
 
+static const struct func kprobe_arg_func = {
+	.name = "argN",
+
+	/* for now, in the future we could read dwarf symbols to
+	 * figure out the real type. */
+	.type = &t_ulong,
+	.static_ret = 1,
+};
+
 static int kprobe_sym_alloc(struct prog *prog, struct node *n)
 {
-	return -ENOENT;
+	const struct func *func = NULL;
+	int err;
+
+	switch (n->ntype) {
+	case N_EXPR:
+		break;
+	case N_IDENT:
+		if (is_arg(n->ident.name))
+			func = &kprobe_arg_func;
+		break;
+	default:
+		break;
+	}
+
+	if (!func)
+		return -ENOENT;
+
+	err = func_static_validate(func, n);
+	if (err)
+		return err;
+
+	n->sym = sym_alloc(prog->locals, n, func);
+
+	if (func->static_ret)
+		n->sym->type = func_return_type(func);
+	return 0;
 }
 
 static int kprobe_probe(struct prog *prog)

ply.c

 					      node_expr("{}",
 							node_ident("t"),
 							node_num("0"),
+							node_expr("time", NULL),
 							node_expr("pid", NULL),
 							NULL),
 					      NULL),

sym.c

 	struct sym **sym;
 
 	symtab_foreach(st, sym) {
-		if (!strcmp((*sym)->name, n->ident.name))
+		if ((*sym)->name && !strcmp((*sym)->name, n->ident.name))
 			return *sym;
 	}