On 4/27/22 13:02, Joseph Myers wrote:
On Wed, 27 Apr 2022, Jason Merrill via Gcc-patches wrote:
+ if (typedef_variant_p (type))
+ {
+ /* Set up the typedef all over again. */
This seems wrong when the typedef is just being used in another
declaration with the mode attribute, as opposed to being defined using the
mode attribute. E.g. the following test is valid and accepted before the
patch, but wrongly rejected after the patch because the typedef has had
its type changed.
typedef int I;
int x;
I y __attribute__ ((mode(QI)));
extern I x;
Ah, good point. Fixed thus:
From 35210478aa12623dcf027b7a14ea5216d93a46e4 Mon Sep 17 00:00:00 2001
From: Jason Merrill <ja...@redhat.com>
Date: Fri, 15 Apr 2022 16:27:05 -0400
Subject: [PATCH] c-family: attribute ((aligned, mode)) [PR100545]
To: gcc-patches@gcc.gnu.org
The problem here was that handle_mode_attribute clobbered the changes of any
previous attribute, only copying type qualifiers to the new type. And
common_handle_aligned_attribute had previously set up the typedef, so when
we later called set_underlying_type it saw DECL_ORIGINAL_TYPE set and just
returned, even though handle_mode_attribute had messed up the TREE_TYPE.
So, let's fix handle_mode_attribute to copy attributes, alignment, and
typedefness to the new type.
PR c/100545
gcc/c-family/ChangeLog:
* c-attribs.cc (handle_mode_attribute): Copy attributes, aligned,
and typedef.
* c-common.cc (set_underlying_type): Add assert.
gcc/testsuite/ChangeLog:
* c-c++-common/attr-mode-1.c: New test.
* c-c++-common/attr-mode-2.c: New test.
---
gcc/c-family/c-attribs.cc | 16 +++++++++++++++-
gcc/c-family/c-common.cc | 7 ++++---
gcc/testsuite/c-c++-common/attr-mode-1.c | 3 +++
gcc/testsuite/c-c++-common/attr-mode-2.c | 4 ++++
4 files changed, 26 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/c-c++-common/attr-mode-1.c
create mode 100644 gcc/testsuite/c-c++-common/attr-mode-2.c
diff --git a/gcc/c-family/c-attribs.cc b/gcc/c-family/c-attribs.cc
index 111a33f405a..b1953a45f9b 100644
--- a/gcc/c-family/c-attribs.cc
+++ b/gcc/c-family/c-attribs.cc
@@ -2199,7 +2199,21 @@ handle_mode_attribute (tree *node, tree name, tree args,
return NULL_TREE;
}
- *node = build_qualified_type (typefm, TYPE_QUALS (type));
+ /* Copy any quals and attributes to the new type. */
+ *node = build_type_attribute_qual_variant (typefm, TYPE_ATTRIBUTES (type),
+ TYPE_QUALS (type));
+ if (TYPE_USER_ALIGN (type))
+ *node = build_aligned_type (*node, TYPE_ALIGN (type));
+
+ tree decl = node[2];
+ if (decl && TYPE_NAME (type) == decl)
+ {
+ /* Set up the typedef all over again. */
+ DECL_ORIGINAL_TYPE (decl) = NULL_TREE;
+ TREE_TYPE (decl) = *node;
+ set_underlying_type (decl);
+ *node = TREE_TYPE (decl);
+ }
}
return NULL_TREE;
diff --git a/gcc/c-family/c-common.cc b/gcc/c-family/c-common.cc
index bb0544eeaea..730faa9e87f 100644
--- a/gcc/c-family/c-common.cc
+++ b/gcc/c-family/c-common.cc
@@ -8153,15 +8153,16 @@ check_missing_format_attribute (tree ltype, tree rtype)
void
set_underlying_type (tree x)
{
- if (x == error_mark_node)
+ if (x == error_mark_node || TREE_TYPE (x) == error_mark_node)
return;
if (DECL_IS_UNDECLARED_BUILTIN (x) && TREE_CODE (TREE_TYPE (x)) != ARRAY_TYPE)
{
if (TYPE_NAME (TREE_TYPE (x)) == 0)
TYPE_NAME (TREE_TYPE (x)) = x;
}
- else if (TREE_TYPE (x) != error_mark_node
- && DECL_ORIGINAL_TYPE (x) == NULL_TREE)
+ else if (DECL_ORIGINAL_TYPE (x))
+ gcc_checking_assert (TYPE_NAME (TREE_TYPE (x)) == x);
+ else
{
tree tt = TREE_TYPE (x);
DECL_ORIGINAL_TYPE (x) = tt;
diff --git a/gcc/testsuite/c-c++-common/attr-mode-1.c b/gcc/testsuite/c-c++-common/attr-mode-1.c
new file mode 100644
index 00000000000..59b20cd99e8
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/attr-mode-1.c
@@ -0,0 +1,3 @@
+// PR c/100545
+
+typedef int fatp_t __attribute__((aligned, mode(SI)));
diff --git a/gcc/testsuite/c-c++-common/attr-mode-2.c b/gcc/testsuite/c-c++-common/attr-mode-2.c
new file mode 100644
index 00000000000..de65f49c6b6
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/attr-mode-2.c
@@ -0,0 +1,4 @@
+typedef int I;
+int x;
+I y __attribute__ ((mode(QI)));
+extern I x;
--
2.27.0
