scc

commit 195cc1977d51217abaf20467714bc78c320221cd
parent a73e9f76d9fd0691add07e42337884ee4a57cbef
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Sun, 19 Jul 2015 11:26:34 +0200

Warn when a local symbol is defined but not used

Diffstat:
M
cc1/cc1.h
 | 
19
++++++++++---------
M
cc1/expr.c
 | 
1
+
M
cc1/stmt.c
 | 
1
+
M
cc1/symbol.c
 | 
6
++++--

4 files changed, 16 insertions(+), 11 deletions(-)
diff --git a/cc1/cc1.h b/cc1/cc1.h
@@ -34,7 +34,7 @@ struct symbol {
 	unsigned char ctx;
 	unsigned char ns;
 	unsigned char token;
-	char flags;
+	short flags;
 	union {
 		int i;
 		char *s;
@@ -111,14 +111,15 @@ enum {
 
 /* symbol flags */
 enum {
-	ISGLOBAL   =  1,
-	ISSTATIC   =  2,
-	ISAUTO     =  4,
-	ISREGISTER =  8,
-	ISDEFINED  = 16,
-	ISFIELD    = 32,
-	ISPARAM    = 64,
-	ISEXTERN   =128
+	ISGLOBAL   =       1,
+	ISSTATIC   =       2,
+	ISAUTO     =       4,
+	ISREGISTER =       8,
+	ISDEFINED  =      16,
+	ISFIELD    =      32,
+	ISPARAM    =      64,
+	ISEXTERN   =     128,
+	ISUSED     =     256
 };
 
 
diff --git a/cc1/expr.c b/cc1/expr.c
@@ -473,6 +473,7 @@ primary(void)
 			yylval.sym->flags |= ISDEFINED;
 			error("'%s' undeclared", yytext);
 		}
+		yylval.sym->flags |= ISUSED;
 		np = varnode(yylval.sym);
 		next();
 		break;
diff --git a/cc1/stmt.c b/cc1/stmt.c
@@ -201,6 +201,7 @@ Goto(Symbol *lbreak, Symbol *lcont, Caselist *lswitch)
 	next();
 	if (yytoken != IDEN)
 		unexpected();
+	yylval.sym->flags |= ISUSED;
 	emit(OJUMP, yylval.sym);
 	next();
 	expect(';');
diff --git a/cc1/symbol.c b/cc1/symbol.c
@@ -71,7 +71,6 @@ popctx(void)
 				goto save_symbol;
 			if (sym->flags & ISDEFINED)
 				break;
-			/* TODO: check if the label was used */
 			printerr("label '%s' is not defined", sym->name);
 			break;
 		case NS_CPP:
@@ -87,8 +86,11 @@ popctx(void)
 			sym->type->defined = 0;
 			break;
 		}
-		if (sym->name)
+		if (sym->name) {
 			htab[hash(sym->name)] = sym->hash;
+			if ((sym->flags & (ISUSED|ISGLOBAL)) == 0)
+				warn("'%s' defined but not used", sym->name);
+		}
 		free(sym->name);
 		free(sym);
 	}