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* [gcc r13-3046] c++: Disallow jumps into statement expressions
@ 2022-10-03 16:05 Jakub Jelinek
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From: Jakub Jelinek @ 2022-10-03 16:05 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:c823366fdb9069a54a37a3b18b65a4fa69feabfd
commit r13-3046-gc823366fdb9069a54a37a3b18b65a4fa69feabfd
Author: Jakub Jelinek <jakub@redhat.com>
Date: Mon Oct 3 18:04:37 2022 +0200
c++: Disallow jumps into statement expressions
On Fri, Sep 30, 2022 at 04:39:25PM -0400, Jason Merrill wrote:
> > --- gcc/cp/decl.cc.jj 2022-09-22 00:14:55.478599363 +0200
> > +++ gcc/cp/decl.cc 2022-09-22 00:24:01.121178256 +0200
> > @@ -223,6 +223,7 @@ struct GTY((for_user)) named_label_entry
> > bool in_transaction_scope;
> > bool in_constexpr_if;
> > bool in_consteval_if;
> > + bool in_assume;
>
> I think it would be better to reject jumps into statement-expressions like
> the C front-end.
Ok, here is a self-contained patch that does that.
2022-10-03 Jakub Jelinek <jakub@redhat.com>
* cp-tree.h (BCS_STMT_EXPR): New enumerator.
* name-lookup.h (enum scope_kind): Add sk_stmt_expr.
* name-lookup.cc (begin_scope): Handle sk_stmt_expr like sk_block.
* semantics.cc (begin_compound_stmt): For BCS_STMT_EXPR use
sk_stmt_expr.
* parser.cc (cp_parser_statement_expr): Use BCS_STMT_EXPR instead of
BCS_NORMAL.
* decl.cc (struct named_label_entry): Add in_stmt_expr.
(poplevel_named_label_1): Handle sk_stmt_expr.
(check_previous_goto_1): Diagnose entering of statement expression.
(check_goto): Likewise.
* g++.dg/ext/stmtexpr24.C: New test.
Diff:
---
gcc/cp/cp-tree.h | 3 ++-
gcc/cp/decl.cc | 19 ++++++++++++++++---
gcc/cp/name-lookup.cc | 1 +
gcc/cp/name-lookup.h | 1 +
gcc/cp/parser.cc | 2 +-
gcc/cp/semantics.cc | 2 ++
gcc/testsuite/g++.dg/ext/stmtexpr24.C | 27 +++++++++++++++++++++++++++
7 files changed, 50 insertions(+), 5 deletions(-)
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 67aea9653e3..e734bf43437 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -7599,7 +7599,8 @@ enum {
BCS_NO_SCOPE = 1,
BCS_TRY_BLOCK = 2,
BCS_FN_BODY = 4,
- BCS_TRANSACTION = 8
+ BCS_TRANSACTION = 8,
+ BCS_STMT_EXPR = 16
};
extern tree begin_compound_stmt (unsigned int);
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index fb85564a191..07148b9fd4e 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -223,6 +223,7 @@ struct GTY((for_user)) named_label_entry {
bool in_transaction_scope;
bool in_constexpr_if;
bool in_consteval_if;
+ bool in_stmt_expr;
};
#define named_labels cp_function_chain->x_named_labels
@@ -538,6 +539,9 @@ poplevel_named_label_1 (named_label_entry **slot, cp_binding_level *bl)
case sk_transaction:
ent->in_transaction_scope = true;
break;
+ case sk_stmt_expr:
+ ent->in_stmt_expr = true;
+ break;
case sk_block:
if (level_for_constexpr_if (bl->level_chain))
ent->in_constexpr_if = true;
@@ -3487,7 +3491,7 @@ check_previous_goto_1 (tree decl, cp_binding_level* level, tree names,
bool complained = false;
int identified = 0;
bool saw_eh = false, saw_omp = false, saw_tm = false, saw_cxif = false;
- bool saw_ceif = false;
+ bool saw_ceif = false, saw_se = false;
if (exited_omp)
{
@@ -3560,6 +3564,12 @@ check_previous_goto_1 (tree decl, cp_binding_level* level, tree names,
saw_tm = true;
break;
+ case sk_stmt_expr:
+ if (!saw_se)
+ inf = G_(" enters statement expression");
+ saw_se = true;
+ break;
+
case sk_block:
if (!saw_cxif && level_for_constexpr_if (b->level_chain))
{
@@ -3650,12 +3660,13 @@ check_goto (tree decl)
if (ent->in_try_scope || ent->in_catch_scope || ent->in_transaction_scope
|| ent->in_constexpr_if || ent->in_consteval_if
- || ent->in_omp_scope || !vec_safe_is_empty (ent->bad_decls))
+ || ent->in_omp_scope || ent->in_stmt_expr
+ || !vec_safe_is_empty (ent->bad_decls))
{
diagnostic_t diag_kind = DK_PERMERROR;
if (ent->in_try_scope || ent->in_catch_scope || ent->in_constexpr_if
|| ent->in_consteval_if || ent->in_transaction_scope
- || ent->in_omp_scope)
+ || ent->in_omp_scope || ent->in_stmt_expr)
diag_kind = DK_ERROR;
complained = identify_goto (decl, DECL_SOURCE_LOCATION (decl),
&input_location, diag_kind);
@@ -3703,6 +3714,8 @@ check_goto (tree decl)
inform (input_location, " enters %<constexpr if%> statement");
else if (ent->in_consteval_if)
inform (input_location, " enters %<consteval if%> statement");
+ else if (ent->in_stmt_expr)
+ inform (input_location, " enters statement expression");
}
if (ent->in_omp_scope)
diff --git a/gcc/cp/name-lookup.cc b/gcc/cp/name-lookup.cc
index 69d555ddf1f..d6757d1fe5d 100644
--- a/gcc/cp/name-lookup.cc
+++ b/gcc/cp/name-lookup.cc
@@ -4296,6 +4296,7 @@ begin_scope (scope_kind kind, tree entity)
case sk_scoped_enum:
case sk_transaction:
case sk_omp:
+ case sk_stmt_expr:
scope->keep = keep_next_level_flag;
break;
diff --git a/gcc/cp/name-lookup.h b/gcc/cp/name-lookup.h
index 999db33a7e0..7201ae8ead8 100644
--- a/gcc/cp/name-lookup.h
+++ b/gcc/cp/name-lookup.h
@@ -200,6 +200,7 @@ enum scope_kind {
init-statement. */
sk_cond, /* The scope of the variable declared in the condition
of an if or switch statement. */
+ sk_stmt_expr, /* GNU statement expression block. */
sk_function_parms, /* The scope containing function parameters. */
sk_class, /* The scope containing the members of a class. */
sk_scoped_enum, /* The scope containing the enumerators of a C++11
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 8d0e0fa1b87..6c4f840f9d7 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -5272,7 +5272,7 @@ cp_parser_statement_expr (cp_parser *parser)
/* Start the statement-expression. */
tree expr = begin_stmt_expr ();
/* Parse the compound-statement. */
- cp_parser_compound_statement (parser, expr, BCS_NORMAL, false);
+ cp_parser_compound_statement (parser, expr, BCS_STMT_EXPR, false);
/* Finish up. */
expr = finish_stmt_expr (expr, false);
/* Consume the ')'. */
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 5cc5a001498..58b5b433692 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -1761,6 +1761,8 @@ begin_compound_stmt (unsigned int flags)
sk = sk_try;
else if (flags & BCS_TRANSACTION)
sk = sk_transaction;
+ else if (flags & BCS_STMT_EXPR)
+ sk = sk_stmt_expr;
r = do_pushlevel (sk);
}
diff --git a/gcc/testsuite/g++.dg/ext/stmtexpr24.C b/gcc/testsuite/g++.dg/ext/stmtexpr24.C
new file mode 100644
index 00000000000..907d027c6ed
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/stmtexpr24.C
@@ -0,0 +1,27 @@
+// { dg-do compile }
+// { dg-options "" }
+
+void
+foo (int x)
+{
+ bool a = false;
+ if (x == 1)
+ goto l1; // { dg-message "from here" }
+ a = ({ l0:; if (x == 0) goto l0; true; });
+ a = ({ if (x == 0) throw 1; true; });
+ a = ({ l1:; true; }); // { dg-error "jump to label 'l1'" }
+ // { dg-message "enters statement expression" "" { target *-*-* } .-1 }
+ a = ({ l2:; true; }); // { dg-error "jump to label 'l2'" }
+ switch (x)
+ {
+ case 2:
+ a = ({ case 3:; true; }); // { dg-error "jump to case label" }
+ // { dg-message "enters statement expression" "" { target *-*-* } .-1 }
+ a = ({ default:; true; }); // { dg-error "jump to case label" }
+ // { dg-message "enters statement expression" "" { target *-*-* } .-1 }
+ break;
+ }
+ if (x == 4)
+ goto l2; // { dg-message "from here" }
+ // { dg-message "enters statement expression" "" { target *-*-* } .-1 }
+}
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