From 0601a21c66c50884b7030e1e1baf021f10743ae0 Mon Sep 17 00:00:00 2001
From: "benjamin.franksen" <benjamin.franksen@helmholtz-berlin.de>
Date: Fri, 4 Oct 2013 00:12:51 +0000
Subject: [PATCH] snc: deprecated foreign declarations
Foreign declarations have been a bad idea. This became clear after
implementing indirect calls, because as a consequence you get 'used but
not declared' warnings for calls to foreign functions, too. I could
'fix' that with a bit of effort, but that would be misplaced. The C
compiler will warn about undeclared variables and functions anyway, so
why bother? If you really want to know, perhaps for debugging, use -W
option for extra warnings. If you do, you'll now get the more precise
waring 'treating undeclared object xxx as foreign'.
---
src/snc/analysis.c | 10 ++++++++--
src/snc/snl.lem | 1 +
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/src/snc/analysis.c b/src/snc/analysis.c
index 62220498..8451795a 100644
--- a/src/snc/analysis.c
+++ b/src/snc/analysis.c
@@ -283,6 +283,7 @@ static void analyse_declaration(SymTable st, Expr *scope, Expr *defn)
{
Var *vp;
VarList *var_list;
+ static uint seen_foreign = FALSE;
assert(scope); /* precondition */
assert(defn); /* precondition */
@@ -294,7 +295,12 @@ static void analyse_declaration(SymTable st, Expr *scope, Expr *defn)
#ifdef DEBUG
report("declaration: %s\n", vp->name);
#endif
-
+ if (vp->type->tag == T_NONE && !seen_foreign)
+ {
+ warning_at_expr(defn,
+ "foreign declarations are deprecated\n");
+ seen_foreign = TRUE;
+ }
if (scope->type != D_PROG &&
(vp->type->tag == T_NONE || vp->type->tag == T_EVFLAG))
{
@@ -1119,7 +1125,7 @@ static int connect_variable(Expr *ep, Expr *scope, void *parg)
return FALSE;
}
- extra_warning_at_expr(ep, "variable '%s' used but not declared\n",
+ extra_warning_at_expr(ep, "treating undeclared object '%s' as foreign\n",
ep->value);
/* create a pseudo declaration so we can finish the analysis phase */
vp = new(Var);
diff --git a/src/snc/snl.lem b/src/snc/snl.lem
index 89b93887..c9101ad4 100644
--- a/src/snc/snl.lem
+++ b/src/snc/snl.lem
@@ -197,6 +197,7 @@ direct_declarator(p) ::= LPAREN declarator(x) RPAREN.
direct_declarator(p) ::= direct_declarator(x) subscript(s).
{ p = decl_postfix_array(x, s.str); }
+// deprecated
declaration(p) ::= FOREIGN declarators(ds) SEMICOLON.
{ p = decl_add_base_type(ds, mk_no_type()); }
--
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