Hi,
this patch fixes a gimplification error of the va_list argument of va_arg for
target s390. The error was introduced by r223054, the fix for PR66010.
I.
consider test-case:
...
#include <stdarg.h>
int
f1 (int i, ...)
{
int res;
va_list ap;
va_start (ap, i);
res = va_arg (ap, int);
va_end (ap);
return res;
}
...
For target s390, we're running into a gimplification error for valist '&ap' in
gimplify_va_arg_internal when calling:
...
9326 gimplify_expr (&valist, pre_p, post_p, is_gimple_min_lval,
fb_lvalue);
...
Before committing r223054, we were calling instead:
...
9331 gimplify_expr (&valist, pre_p, post_p, is_gimple_val, fb_rvalue);
...
with valist '(struct *) &ap', and the gimplification went fine.
II.
The successful gimplification was triggered using the following path, entering
with valist 'ap':
...
gimplify_va_arg_internal (tree valist, tree type, location_t loc,
gimple_seq *pre_p, gimple_seq *post_p)
{
tree have_va_type = TREE_TYPE (valist);
tree cano_type = targetm.canonical_va_list_type (have_va_type);
if (cano_type != NULL_TREE)
have_va_type = cano_type;
/* Make it easier for the backends by protecting the valist argument
from multiple evaluations. */
if (TREE_CODE (have_va_type) == ARRAY_TYPE)
{
/* For this case, the backends will be expecting a pointer to
TREE_TYPE (abi), but it's possible we've
actually been given an array (an actual TARGET_FN_ABI_VA_LIST).
So fix it. */
if (TREE_CODE (TREE_TYPE (valist)) == ARRAY_TYPE)
{
tree p1 = build_pointer_type (TREE_TYPE (have_va_type));
valist = fold_convert_loc (loc, p1,
build_fold_addr_expr_loc (loc, valist));
}
gimplify_expr (&valist, pre_p, post_p, is_gimple_val, fb_rvalue);
}
...
In r223054, we've moved the fixup of adding the addr_expr to
gimplify_va_arg_expr. Consequently, we're now entering with valist '&ap'. The
have_va_type has changed to 'struct [1] *', and cano_type is NULL_TREE.
So have_va_type is no longer an array, and the other gimplification path is
triggered, which causes the gimplification error.
[ For x86_64, the type of '&ap' is not 'struct [1] *' but 'struct *', and the
cano_type is not NULL_TREE, so we didn't encounter this problem there. ]
III.
The patch fixes this error by inlining gimplify_va_arg_internal into
expand_ifn_va_arg_1, and using the information present there to determine which
gimplification path to choose:
...
if (do_deref == integer_one_node)
gimplify_expr (&ap, &pre, &post, is_gimple_min_lval, fb_lvalue);
else
gimplify_expr (&ap, &pre, &post, is_gimple_val, fb_rvalue);
...
So for an va_list ap given as argument of va_arg:
- in case the canonical va_list is an array type, we take the address in
gimplify_va_arg_expr, set do_deref to zero, meaning we pass '&ap' to
targetm.gimplify_va_arg_expr. The fact that it's an address means we can
expect it to be an rvalue, but not an lvalue.
- in case the canonical va_list is not an array type, we take the address in
gimplify_va_arg_expr, but set do_deref to one, meaning we pass 'ap' to
targetm.gimplify_va_arg_expr. 'ap' may be modified by va_arg, so it needs to
be an lvalue.
IV.
Bootstrapped and reg-tested on x86_64.
Noted to fix s390 bootstrap:
https://gcc.gnu.org/ml/gcc-patches/2015-05/msg01176.html .
Noted to fix ppc build:
https://gcc.gnu.org/ml/gcc-patches/2015-05/msg01162.html .
OK for trunk?
Thanks,
- Tom
Gimplify va_arg ap based on do_deref
2015-05-13 Tom de Vries <t...@codesourcery.com>
PR tree-optimization/66010
* gimplify.h (gimplify_va_arg_internal): Remove declaration.
* gimplify.c (gimplify_va_arg_internal): Remove and inline into ...
* tree-stdarg.c (expand_ifn_va_arg_1): ... here. Choose between lval
and rval based on do_deref.
---
gcc/gimplify.c | 26 --------------------------
gcc/gimplify.h | 1 -
gcc/tree-stdarg.c | 9 ++++++++-
3 files changed, 8 insertions(+), 28 deletions(-)
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 322d0ba..4846478 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -9302,32 +9302,6 @@ dummy_object (tree type)
return build2 (MEM_REF, type, t, t);
}
-/* Call the target expander for evaluating a va_arg call of VALIST
- and TYPE. */
-
-tree
-gimplify_va_arg_internal (tree valist, tree type, gimple_seq *pre_p,
- gimple_seq *post_p)
-{
- tree have_va_type = TREE_TYPE (valist);
- tree cano_type = targetm.canonical_va_list_type (have_va_type);
-
- if (cano_type != NULL_TREE)
- have_va_type = cano_type;
-
- /* Make it easier for the backends by protecting the valist argument
- from multiple evaluations. */
- if (TREE_CODE (have_va_type) == ARRAY_TYPE)
- {
- gcc_assert (TREE_CODE (TREE_TYPE (valist)) != ARRAY_TYPE);
- gimplify_expr (&valist, pre_p, post_p, is_gimple_val, fb_rvalue);
- }
- else
- gimplify_expr (&valist, pre_p, post_p, is_gimple_min_lval, fb_lvalue);
-
- return targetm.gimplify_va_arg_expr (valist, type, pre_p, post_p);
-}
-
/* Gimplify __builtin_va_arg, aka VA_ARG_EXPR, which is not really a
builtin function, but a very special sort of operator. */
diff --git a/gcc/gimplify.h b/gcc/gimplify.h
index 83bf525..615925c 100644
--- a/gcc/gimplify.h
+++ b/gcc/gimplify.h
@@ -82,7 +82,6 @@ extern void gimplify_function_tree (tree);
extern enum gimplify_status gimplify_va_arg_expr (tree *, gimple_seq *,
gimple_seq *);
gimple gimplify_assign (tree, tree, gimple_seq *);
-extern tree gimplify_va_arg_internal (tree, tree, gimple_seq *, gimple_seq *);
/* Return true if gimplify_one_sizepos doesn't need to gimplify
expr (when in TYPE_SIZE{,_UNIT} and similar type/decl size/bitsize
diff --git a/gcc/tree-stdarg.c b/gcc/tree-stdarg.c
index 3bede7e..f8ff70a 100644
--- a/gcc/tree-stdarg.c
+++ b/gcc/tree-stdarg.c
@@ -1059,7 +1059,14 @@ expand_ifn_va_arg_1 (function *fun)
push_gimplify_context (false);
- expr = gimplify_va_arg_internal (ap, type, &pre, &post);
+ /* Make it easier for the backends by protecting the valist argument
+ from multiple evaluations. */
+ if (do_deref == integer_one_node)
+ gimplify_expr (&ap, &pre, &post, is_gimple_min_lval, fb_lvalue);
+ else
+ gimplify_expr (&ap, &pre, &post, is_gimple_val, fb_rvalue);
+
+ expr = targetm.gimplify_va_arg_expr (ap, type, &pre, &post);
lhs = gimple_call_lhs (stmt);
if (lhs != NULL_TREE)
--
1.9.1
