Any comment/review on this patch ?
On Sep 3, 2013, at 4:08 PM, Tristan Gingold <ging...@adacore.com> wrote:
> Hi,
>
> The field state->ehp_region wasn't updated before lowering constructs in the
> eh
> path of EH_ELSE. As a consequence, __builtin_eh_pointer is lowered to 0 (or
> possibly to a wrong region number) in this path.
>
> The only user of EH_ELSE looks to be trans-mem.c:lower_transaction, and the
> consequence of that is a memory leak.
>
> Furthermore, according to calls.c:flags_from_decl_or_type, the
> "transaction_pure"
> attribute must be set on the function type, not on the function declaration.
> Hence the change to declare __builtin_eh_pointer.
> (I don't understand the guard condition to set the attribute for it in tree.c.
> Why is 'builtin_decl_explicit_p (BUILT_IN_TM_LOAD_1)' needed in addition to
> flag_tm ?)
>
> No regressions (check-host) on x86-64 GNU/Linux.
>
> Ok for trunk ?
>
> Tristan.
>
> 2013-09-03 Tristan Gingold <ging...@adacore.com>
>
> * tree.c (set_call_expr_flags): Reject ECF_TM_PURE.
> (build_common_builtin_nodes): Set "transaction_pure"
> attribute on __builtin_eh_pointer function type (and not on
> its declaration).
> * tree-eh.c (lower_try_finally_nofallthru): Set and revert
> ehp_region before callinf lower_eh_constructs_1.
> (lower_try_finally_onedest): Likewise.
> (lower_try_finally_copy): Likewise.
> (lower_try_finally_switch): Likewise.
>
> testsuite/
> 2013-09-03 Tristan Gingold <ging...@adacore.com>
>
> * gcc.dg/tm/except.c: New testcase.
>
>
> diff --git a/gcc/testsuite/gcc.dg/tm/except.c
> b/gcc/testsuite/gcc.dg/tm/except.c
> new file mode 100644
> index 0000000..ed84bb3
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tm/except.c
> @@ -0,0 +1,36 @@
> +/* { dg-do compile } */
> +/* { dg-options "-fgnu-tm -O1 -fexceptions -fdump-tree-optimized" } */
> +
> +typedef struct node {
> + int val;
> + struct node *next;
> +} node_t;
> +
> +node_t *head;
> +
> +__attribute__((transaction_safe))
> +node_t *new_node(int val, node_t *next);
> +
> +int add(int val)
> +{
> + int result;
> + node_t *prev, *next;
> +
> + __transaction_atomic {
> + prev = head;
> + next = prev->next;
> + while (next->val < val) {
> + prev = next;
> + next = prev->next;
> + }
> + result = (next->val != val);
> + if (result) {
> + prev->next = new_node(val, next);
> + }
> + }
> + return result;
> +}
> +
> +/* { dg-final { scan-tree-dump-not "ITM_commitTransactionEH \\(0B\\)"
> "optimized" } } */
> +
> +/* { dg-final { cleanup-tree-dump "optimized" } } */
> diff --git a/gcc/tree-eh.c b/gcc/tree-eh.c
> index 6ffbd26..86ee77e 100644
> --- a/gcc/tree-eh.c
> +++ b/gcc/tree-eh.c
> @@ -1093,8 +1093,12 @@ lower_try_finally_nofallthru (struct leh_state *state,
>
> if (tf->may_throw)
> {
> + eh_region prev_ehp_region = state->ehp_region;
> +
> finally = gimple_eh_else_e_body (eh_else);
> + state->ehp_region = tf->region;
> lower_eh_constructs_1 (state, &finally);
> + state->ehp_region = prev_ehp_region;
>
> emit_post_landing_pad (&eh_seq, tf->region);
> gimple_seq_add_seq (&eh_seq, finally);
> @@ -1129,6 +1133,7 @@ lower_try_finally_onedest (struct leh_state *state,
> struct leh_tf_state *tf)
> gimple_stmt_iterator gsi;
> tree finally_label;
> location_t loc = gimple_location (tf->try_finally_expr);
> + eh_region prev_ehp_region = state->ehp_region;
>
> finally = gimple_try_cleanup (tf->top_p);
> tf->top_p_seq = gimple_try_eval (tf->top_p);
> @@ -1140,12 +1145,16 @@ lower_try_finally_onedest (struct leh_state *state,
> struct leh_tf_state *tf)
> if (x)
> {
> if (tf->may_throw)
> - finally = gimple_eh_else_e_body (x);
> + {
> + state->ehp_region = tf->region;
> + finally = gimple_eh_else_e_body (x);
> + }
> else
> finally = gimple_eh_else_n_body (x);
> }
>
> lower_eh_constructs_1 (state, &finally);
> + state->ehp_region = prev_ehp_region;
>
> for (gsi = gsi_start (finally); !gsi_end_p (gsi); gsi_next (&gsi))
> {
> @@ -1255,13 +1264,19 @@ lower_try_finally_copy (struct leh_state *state,
> struct leh_tf_state *tf)
>
> if (tf->may_throw)
> {
> + eh_region prev_ehp_region = state->ehp_region;
> +
> /* We don't need to copy the EH path of EH_ELSE,
> since it is only emitted once. */
> if (eh_else)
> - seq = gimple_eh_else_e_body (eh_else);
> + {
> + seq = gimple_eh_else_e_body (eh_else);
> + state->ehp_region = tf->region;
> + }
> else
> seq = lower_try_finally_dup_block (finally, state, tf_loc);
> lower_eh_constructs_1 (state, &seq);
> + state->ehp_region = prev_ehp_region;
>
> emit_post_landing_pad (&eh_seq, tf->region);
> gimple_seq_add_seq (&eh_seq, seq);
> @@ -1432,8 +1447,12 @@ lower_try_finally_switch (struct leh_state *state,
> struct leh_tf_state *tf)
> {
> if (tf->may_throw)
> {
> + eh_region prev_ehp_region = state->ehp_region;
> +
> + state->ehp_region = tf->region;
> finally = gimple_eh_else_e_body (eh_else);
> lower_eh_constructs_1 (state, &finally);
> + state->ehp_region = prev_ehp_region;
>
> emit_post_landing_pad (&eh_seq, tf->region);
> gimple_seq_add_seq (&eh_seq, finally);
> diff --git a/gcc/tree.c b/gcc/tree.c
> index f0ee309..e4be24d 100644
> --- a/gcc/tree.c
> +++ b/gcc/tree.c
> @@ -9817,9 +9817,11 @@ set_call_expr_flags (tree decl, int flags)
> if (flags & ECF_LEAF)
> DECL_ATTRIBUTES (decl) = tree_cons (get_identifier ("leaf"),
> NULL, DECL_ATTRIBUTES (decl));
> - if ((flags & ECF_TM_PURE) && flag_tm)
> - DECL_ATTRIBUTES (decl) = tree_cons (get_identifier ("transaction_pure"),
> - NULL, DECL_ATTRIBUTES (decl));
> +
> + /* The "transaction_pure" attribute must be set on the function type, not
> + on the declaration. */
> + gcc_assert (!(flags & ECF_TM_PURE));
> +
> /* Looping const or pure is implied by noreturn.
> There is currently no way to declare looping const or looping pure
> alone. */
> gcc_assert (!(flags & ECF_LOOPING_CONST_OR_PURE)
> @@ -10018,8 +10020,9 @@ build_common_builtin_nodes (void)
> integer_type_node, NULL_TREE);
> ecf_flags = ECF_PURE | ECF_NOTHROW | ECF_LEAF;
> /* Only use TM_PURE if we we have TM language support. */
> - if (builtin_decl_explicit_p (BUILT_IN_TM_LOAD_1))
> - ecf_flags |= ECF_TM_PURE;
> + if (flag_tm && builtin_decl_explicit_p (BUILT_IN_TM_LOAD_1))
> + TYPE_ATTRIBUTES (ftype) = tree_cons (get_identifier ("transaction_pure"),
> + NULL, TYPE_ATTRIBUTES (ftype));
> local_define_builtin ("__builtin_eh_pointer", ftype, BUILT_IN_EH_POINTER,
> "__builtin_eh_pointer", ecf_flags);
>
>
