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Re: C PATCH for c/68668 (grokdeclarator and wrong type of PARM_DECL)
- From: Marek Polacek <polacek at redhat dot com>
- To: Joseph Myers <joseph at codesourcery dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 3 Dec 2015 22:26:56 +0100
- Subject: Re: C PATCH for c/68668 (grokdeclarator and wrong type of PARM_DECL)
- Authentication-results: sourceware.org; auth=none
- References: <20151203175646 dot GI3175 at redhat dot com> <alpine dot DEB dot 2 dot 10 dot 1512031809290 dot 16579 at digraph dot polyomino dot org dot uk>
On Thu, Dec 03, 2015 at 06:11:42PM +0000, Joseph Myers wrote:
> On Thu, 3 Dec 2015, Marek Polacek wrote:
>
> > This ought to fix the fallout from PR c/68162 fix. Here the problem is that
> > grokdeclarator created a wrong type for PARM_DECL "p". It created this decl
> > with type "const int[<unknown>] *" while it should be "const int *".
> >
> > I think the problem is that we weren't using TREE_TYPE on orig_qual_type and
> > thus c_build_qualified_type and subsequent c_build_pointer_type might create
> > a bogus type. So when we're transfering const-ness of an array into that of
> > type pointed to, use TREE_TYPE not only of "type", but even of the orig qual
> > type.
>
> I think you also need to decrement orig_qual_indirect, which counts the
> number of levels of array type derivation from orig_qual_type.
Thus:
Bootstrapped/regtested on x86_64-linux, ok for trunk?
2015-12-03 Marek Polacek <polacek@redhat.com>
PR c/68668
* c-decl.c (grokdeclarator): When creating a PARM_DECL of ARRAY_TYPE,
use TREE_TYPE of orig_qual_type. Decrement ORIG_QUAL_INDIRECT.
* gcc.dg/pr68668.c: New test.
diff --git gcc/c/c-decl.c gcc/c/c-decl.c
index 9ad8219..25bd1e0 100644
--- gcc/c/c-decl.c
+++ gcc/c/c-decl.c
@@ -6417,6 +6417,11 @@ grokdeclarator (const struct c_declarator *declarator,
{
/* Transfer const-ness of array into that of type pointed to. */
type = TREE_TYPE (type);
+ if (orig_qual_type != NULL_TREE)
+ {
+ orig_qual_type = TREE_TYPE (orig_qual_type);
+ orig_qual_indirect--;
+ }
if (type_quals)
type = c_build_qualified_type (type, type_quals, orig_qual_type,
orig_qual_indirect);
diff --git gcc/testsuite/gcc.dg/pr68668.c gcc/testsuite/gcc.dg/pr68668.c
index e69de29..d144fb6 100644
--- gcc/testsuite/gcc.dg/pr68668.c
+++ gcc/testsuite/gcc.dg/pr68668.c
@@ -0,0 +1,10 @@
+/* PR c/68668 */
+/* { dg-do compile } */
+
+typedef const int T[];
+
+int
+fn1 (T p)
+{
+ return p[0];
+}
Marek