[PATCH 0/3] warn on empty expressions

[PATCH 0/3] warn on empty expressions

[Luc Van Oostenryck]

Sparse silently accepts empty assignments and empty initializers.
This series makes them an error.

Luc Van Oostenryck (3):
  add testcase for incorrect empty expressions
  warn on empty assignments
  warn on empty initializations

 expression.c                   |  6 +++++-
 parse.c                        |  5 ++++-
 validation/bad-assignment.c    |  1 +
 validation/empty-assign.c      | 13 +++++++++++++
 validation/empty-initializer.c |  9 +++++++++
 5 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 validation/empty-assign.c
 create mode 100644 validation/empty-initializer.c


base-commit: c9676a3b0349a1053c673243af52a2ef1b272bd7
-- 
2.27.0

[PATCH 1/3] add testcase for incorrect empty expressions

[Luc Van Oostenryck]

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 validation/empty-assign.c      | 14 ++++++++++++++
 validation/empty-initializer.c | 10 ++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 validation/empty-assign.c
 create mode 100644 validation/empty-initializer.c

diff --git a/validation/empty-assign.c b/validation/empty-assign.c
new file mode 100644
index 000000000000..48ac626ddaed
--- /dev/null
+++ b/validation/empty-assign.c
@@ -0,0 +1,14 @@
+static int foo(int a)
+{
+	a = ;			// KO
+	return a;
+}
+
+/*
+ * check-name: empty-assign
+ * check-known-to-fail
+ *
+ * check-error-start
+empty-assign.c:3:11: error: expression expected before ';'
+ * check-error-end
+ */
diff --git a/validation/empty-initializer.c b/validation/empty-initializer.c
new file mode 100644
index 000000000000..0ca763f699a0
--- /dev/null
+++ b/validation/empty-initializer.c
@@ -0,0 +1,10 @@
+static int i = ;		// KO
+
+/*
+ * check-name: empty-initializer
+ * check-known-to-fail
+ *
+ * check-error-start
+empty-initializer.c:1:16: error: expression expected before ';'
+ * check-error-end
+ */
-- 
2.27.0

[PATCH 2/3] warn on empty assignments

[Luc Van Oostenryck]

Currently sparse accepts an empty assignment like:
	a = ;

Make this an error.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 expression.c                | 6 +++++-
 validation/bad-assignment.c | 1 +
 validation/empty-assign.c   | 1 -
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/expression.c b/expression.c
index 1160cd9cc593..ecbdd18eb402 100644
--- a/expression.c
+++ b/expression.c
@@ -937,10 +937,14 @@ struct token *assignment_expression(struct token *token, struct expression **tre
 		for (i = 0; i < ARRAY_SIZE(assignments); i++)
 			if (assignments[i] == op) {
 				struct expression * expr = alloc_expression(token->pos, EXPR_ASSIGNMENT);
+				struct token *next = token->next;
 				expr->left = *tree;
 				expr->op = op;
 				*tree = expr;
-				return assignment_expression(token->next, &expr->right);
+				token = assignment_expression(next, &expr->right);
+				if (token == next)
+					expression_error(expr, "expression expected before '%s'", show_token(token));
+				return token;
 			}
 	}
 	return token;
diff --git a/validation/bad-assignment.c b/validation/bad-assignment.c
index 71938db7c4f5..959712beda94 100644
--- a/validation/bad-assignment.c
+++ b/validation/bad-assignment.c
@@ -8,6 +8,7 @@ static int foo(int a)
  * check-name: bad assignment
  *
  * check-error-start
+bad-assignment.c:3:11: error: expression expected before '\'
 bad-assignment.c:3:13: error: Expected ; at end of statement
 bad-assignment.c:3:13: error: got \
  * check-error-end
diff --git a/validation/empty-assign.c b/validation/empty-assign.c
index 48ac626ddaed..d1c3884f71e8 100644
--- a/validation/empty-assign.c
+++ b/validation/empty-assign.c
@@ -6,7 +6,6 @@ static int foo(int a)
 
 /*
  * check-name: empty-assign
- * check-known-to-fail
  *
  * check-error-start
 empty-assign.c:3:11: error: expression expected before ';'
-- 
2.27.0

[PATCH 3/3] warn on empty initializations

[Luc Van Oostenryck]

Currently sparse accepts an empty initialization like:
	int a = ;

Make this an error.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 parse.c                        | 5 ++++-
 validation/empty-initializer.c | 1 -
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/parse.c b/parse.c
index a9222e7cbf08..d0a41b14b914 100644
--- a/parse.c
+++ b/parse.c
@@ -3117,7 +3117,10 @@ struct token *external_declaration(struct token *token, struct symbol_list **lis
 
 	for (;;) {
 		if (!is_typedef && match_op(token, '=')) {
-			token = initializer(&decl->initializer, token->next);
+			struct token *next = token->next;
+			token = initializer(&decl->initializer, next);
+			if (token == next)
+				sparse_error(token->pos, "expression expected before '%s'", show_token(token));
 		}
 		if (!is_typedef) {
 			if (validate_decl)
diff --git a/validation/empty-initializer.c b/validation/empty-initializer.c
index 0ca763f699a0..950679991401 100644
--- a/validation/empty-initializer.c
+++ b/validation/empty-initializer.c
@@ -2,7 +2,6 @@ static int i = ;		// KO
 
 /*
  * check-name: empty-initializer
- * check-known-to-fail
  *
  * check-error-start
 empty-initializer.c:1:16: error: expression expected before ';'
-- 
2.27.0