From: Michael Beck <beck@ipd.info.uni-karlsruhe.de>
Date: Sat, 15 Dec 2007 02:49:56 +0000 (+0000)
Subject: - implemented -Wunused-label
X-Git-Url: http://nsz.repo.hu/git/?a=commitdiff_plain;h=78cc65b14fc5c53a16368fe5975c70c83e969b19;p=cparser

- implemented -Wunused-label

[r18759]
---

diff --git a/ast_t.h b/ast_t.h
index 89a9f59..7efa194 100644
--- a/ast_t.h
+++ b/ast_t.h
@@ -397,6 +397,7 @@ struct declaration_t {
 	decl_modifiers_t    modifiers;
 	unsigned int        address_taken : 1;
 	unsigned int        is_inline     : 1;
+	unsigned int        used          : 1;  /**< Set if the declaration is used. */
 	type_t             *type;
 	symbol_t           *symbol;
 	source_position_t   source_position;
@@ -482,8 +483,8 @@ struct switch_statement_t {
 
 struct goto_statement_t {
 	statement_base_t  statement;
-	declaration_t    *label;
-	goto_statement_t *next; /**< link all goto statements in a function */
+	declaration_t    *label;     /**< The destination label. */
+	goto_statement_t *next;      /**< links all goto statements of a function */
 };
 
 struct case_label_statement_t {
@@ -494,9 +495,10 @@ struct case_label_statement_t {
 };
 
 struct label_statement_t {
-	statement_base_t  statement;
-	declaration_t    *label;
-	statement_t      *label_statement;
+	statement_base_t   statement;
+	declaration_t     *label;
+	statement_t       *label_statement;
+	label_statement_t *next;            /**< links all label statements of a function */
 };
 
 struct expression_statement_t {
diff --git a/parser.c b/parser.c
index f95d1af..c769d34 100644
--- a/parser.c
+++ b/parser.c
@@ -52,6 +52,8 @@ static switch_statement_t *current_switch    = NULL;
 static statement_t        *current_loop      = NULL;
 static goto_statement_t   *goto_first        = NULL;
 static goto_statement_t   *goto_last         = NULL;
+static label_statement_t  *label_first       = NULL;
+static label_statement_t  *label_last        = NULL;
 static struct obstack  temp_obst;
 
 /** The current source position. */
@@ -2713,27 +2715,49 @@ static void parse_kr_declaration_list(declaration_t *declaration)
 
 /**
  * Check if all labels are defined in the current function.
+ * Check if all labels are used in the current function.
  */
-static void check_for_missing_labels(void)
+static void check_labels(void)
 {
 	bool first_err = true;
 	for (const goto_statement_t *goto_statement = goto_first;
-	     goto_statement != NULL;
-	     goto_statement = goto_statement->next) {
-		 const declaration_t *label = goto_statement->label;
-
-		 if (label->source_position.input_name == NULL) {
-			 if (first_err) {
-				 first_err = false;
-				 diagnosticf("%s: In function '%Y':\n",
-					 current_function->source_position.input_name,
-					 current_function->symbol);
-			 }
-			 errorf(goto_statement->statement.source_position,
-				 "label '%Y' used but not defined", label->symbol);
+	    goto_statement != NULL;
+	    goto_statement = goto_statement->next) {
+		declaration_t *label = goto_statement->label;
+
+		label->used = true;
+		if (label->source_position.input_name == NULL) {
+			if (first_err) {
+				first_err = false;
+				diagnosticf("%s: In function '%Y':\n",
+					current_function->source_position.input_name,
+					current_function->symbol);
+			}
+			errorf(goto_statement->statement.source_position,
+				"label '%Y' used but not defined", label->symbol);
 		 }
 	}
 	goto_first = goto_last = NULL;
+
+	if (warning.unused_label) {
+		for (const label_statement_t *label_statement = label_first;
+			 label_statement != NULL;
+			 label_statement = label_statement->next) {
+			const declaration_t *label = label_statement->label;
+
+			if (! label->used) {
+				if (first_err) {
+					first_err = false;
+					diagnosticf("%s: In function '%Y':\n",
+						current_function->source_position.input_name,
+						current_function->symbol);
+				}
+				warningf(label_statement->statement.source_position,
+					"label '%Y' defined but not used", label->symbol);
+			}
+		}
+	}
+	label_first = label_last = NULL;
 }
 
 static void parse_external_declaration(void)
@@ -2827,7 +2851,7 @@ static void parse_external_declaration(void)
 		current_function                    = declaration;
 
 		declaration->init.statement = parse_compound_statement();
-		check_for_missing_labels();
+		check_labels();
 
 		assert(current_function == declaration);
 		current_function = old_current_function;
@@ -5105,6 +5129,13 @@ static statement_t *parse_label_statement(void)
 		}
 	}
 
+	/* remember the labels's in a list for later checking */
+	if (label_last == NULL) {
+		label_first = label_last = label_statement;
+	} else {
+		label_last->next = label_statement;
+	}
+
 	return (statement_t*) label_statement;
 }
 
diff --git a/warning.c b/warning.c
index f39e16c..63cbeac 100644
--- a/warning.c
+++ b/warning.c
@@ -36,6 +36,7 @@ void set_warning_opt(const char *const opt)
 	OPT("strict-prototypes",             strict_prototypes)
 	OPT("switch-default",                switch_default)
 	OPT("unknown-pragmas",               unknown_pragmas)
+	OPT("unused-label",                  unused_label)
 #if 0
 	OPTX("unused") {
 		SET(unused_function)
diff --git a/warning.h b/warning.h
index 6ebcd40..c251a70 100644
--- a/warning.h
+++ b/warning.h
@@ -73,7 +73,9 @@ typedef struct warning_t {
 #if 0 // TODO
 	bool unreachable_code:1;              /**< Warn if the compiler detects that code will never be executed */
 	bool unused_function:1;               /**< Warn whenever a static function is declared but not defined or a non-inline static function is unused */
+#endif
 	bool unused_label:1;                  /**< Warn whenever a label is declared but not used */
+#if 0 // TODO
 	bool unused_parameter:1;              /**< Warn whenever a function parameter is unused aside from its declaration */
 	bool unused_variable:1;               /**< Warn whenever a local variable or non-constant static variable is unused aside from its declaration */
 #endif