https://gcc.gnu.org/g:0183fb1cef5e382af2a5c0dc3c59efbcd32db6ab
commit r14-11146-g0183fb1cef5e382af2a5c0dc3c59efbcd32db6ab
Author: Jakub Jelinek <ja...@redhat.com>
Date: Wed Nov 27 17:29:28 2024 +0100
c: Fix sizeof error recovery [PR117745]
Compilation of the following testcase hangs forever after emitting first
error. The problem is that in one place we just return error_mark_node
directly rather than going through c_expr_sizeof_expr or c_expr_sizeof_type.
The parsing of the expression could have called record_maybe_used_decl
though, but nothing calls pop_maybe_used which needs to be called after
parsing of every sizeof/typeof, successful or not.
At the end of the toplevel declaration we free the parser_obstack and in
another function record_maybe_used_decl is called again and due to the
missing pop_maybe_unused we end up with a cycle in the chain.
The following patch fixes it by just setting error and goto to the
sizeof_expr:
c_inhibit_evaluation_warnings--;
in_sizeof--;
mark_exp_read (expr.value);
if (TREE_CODE (expr.value) == COMPONENT_REF
&& DECL_C_BIT_FIELD (TREE_OPERAND (expr.value, 1)))
error_at (expr_loc, "%<sizeof%> applied to a bit-field");
result = c_expr_sizeof_expr (expr_loc, expr);
where c_expr_sizeof_expr will do:
struct c_expr ret;
if (expr.value == error_mark_node)
{
ret.value = error_mark_node;
ret.original_code = ERROR_MARK;
ret.original_type = NULL;
ret.m_decimal = 0;
pop_maybe_used (false);
}
...
return ret;
which is exactly what the old code did manually except for the missing
pop_maybe_used call. mark_exp_read does nothing on error_mark_node and
error_mark_node doesn't have COMPONENT_REF tree_code.
2024-11-27 Jakub Jelinek <ja...@redhat.com>
PR c/117745
* c-parser.cc (c_parser_sizeof_expression): If type_name is NULL,
just expr.set_error () and goto sizeof_expr instead of doing error
recovery manually.
* gcc.dg/pr117745.c: New test.
(cherry picked from commit 958f0025f41d8bd9812e4da91a72b1ad79496e5b)
Diff:
---
gcc/c/c-parser.cc | 12 +++++-------
gcc/testsuite/gcc.dg/pr117745.c | 8 ++++++++
2 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 5fcfff7134a8..cd2e089fe38d 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -9891,13 +9891,11 @@ c_parser_sizeof_expression (c_parser *parser)
finish = parser->tokens_buf[0].location;
if (type_name == NULL)
{
- struct c_expr ret;
- c_inhibit_evaluation_warnings--;
- in_sizeof--;
- ret.set_error ();
- ret.original_code = ERROR_MARK;
- ret.original_type = NULL;
- return ret;
+ /* Let c_expr_sizeof_expr call pop_maybe_used and fill in c_expr
+ for parsing error; the parsing of the expression could have
+ called record_maybe_used_decl. */
+ expr.set_error ();
+ goto sizeof_expr;
}
if (c_parser_next_token_is (parser, CPP_OPEN_BRACE))
{
diff --git a/gcc/testsuite/gcc.dg/pr117745.c b/gcc/testsuite/gcc.dg/pr117745.c
new file mode 100644
index 000000000000..3485f7c9b1ab
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr117745.c
@@ -0,0 +1,8 @@
+/* PR c/117745 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+static int foo (void);
+void bar (void) { sizeof (int [0 ? foo () : 1); } /* { dg-error
"expected" } */
+static int baz (void);
+void qux (void) { sizeof (sizeof (int[baz ()])); }
