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[PATCH, C] Fix PR40563
- From: Shujing Zhao <pearly dot zhao at oracle dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Cc: "Joseph S. Myers" <joseph at codesourcery dot com>, Paolo Carlini <paolo dot carlini at oracle dot com>
- Date: Wed, 21 Jul 2010 11:09:15 +0800
- Subject: [PATCH, C] Fix PR40563
Hi,
This patch diagnose uninitialized const field in struct or union when
-Wc++-compat enabled.
Tested on i686-pc-linux-gnu with no regression.
ok for trunk?
/gcc
2010-07-21 Shujing Zhao <pearly.zhao@oracle.com>
PR c/40563
* c-decl.c (diagnose_uninitialized_cst_member): New function.
(finish_decl): Use it to issue a -Wc++-compat warning about
uninitialized const field in struct or union.
/gcc/testsuite
2010-07-21 Shujing Zhao <pearly.zhao@oracle.com>
PR c/40563
* gcc.dg/Wcxx-compat-20.c: New test
Index: c-decl.c
===================================================================
--- c-decl.c (revision 162361)
+++ c-decl.c (working copy)
@@ -4103,6 +4103,35 @@ start_decl (struct c_declarator *declara
return tem;
}
+/* Subroutine of finish_decl. Diagnose uninitialized const member of type TYPE.
+ DECL is the original declaration. */
+
+static void
+diagnose_uninitialized_cst_member (tree decl, tree type)
+{
+ tree field;
+ for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
+ {
+ tree field_type;
+ if (TREE_CODE (field) != FIELD_DECL)
+ continue;
+ field_type = strip_array_types (TREE_TYPE (field));
+
+ if (TYPE_QUALS (field_type) & TYPE_QUAL_CONST)
+ {
+ warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wc___compat,
+ "uninitialized const member in %qT is invalid in C++",
+ TREE_TYPE (decl));
+ inform (DECL_SOURCE_LOCATION (field), "%qD should be initialized", field);
+ }
+
+ if (TREE_CODE (field_type) == RECORD_TYPE
+ || TREE_CODE (field_type) == UNION_TYPE)
+ diagnose_uninitialized_cst_member (decl, field_type);
+ }
+}
+
+
/* Finish processing of a declaration;
install its initial value.
If ORIGTYPE is not NULL_TREE, it is the original type of INIT.
@@ -4420,11 +4449,16 @@ finish_decl (tree decl, location_t init_
if (warn_cxx_compat
&& TREE_CODE (decl) == VAR_DECL
- && TREE_READONLY (decl)
&& !DECL_EXTERNAL (decl)
&& DECL_INITIAL (decl) == NULL_TREE)
- warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wc___compat,
- "uninitialized const %qD is invalid in C++", decl);
+ {
+ if (TREE_READONLY (decl))
+ warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wc___compat,
+ "uninitialized const %qD is invalid in C++", decl);
+ else if (TREE_CODE (type) == RECORD_TYPE
+ || TREE_CODE (type) == UNION_TYPE)
+ diagnose_uninitialized_cst_member (decl, type);
+ }
}
/* Given a parsed parameter declaration, decode it into a PARM_DECL. */
Index: testsuite/gcc.dg/Wcxx-compat-20.c
===================================================================
--- testsuite/gcc.dg/Wcxx-compat-20.c (revision 0)
+++ testsuite/gcc.dg/Wcxx-compat-20.c (revision 0)
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-Wc++-compat" } */
+typedef struct s { const int i; } s; /* { dg-message "should be initialized" } */
+void foo () { s v; } /* { dg-warning "uninitialized const member in" } */
+
+union u {const int a; double b;}; /* { dg-message "should be initialized" } */
+void bar () { union u f; } /* { dg-warning "uninitialized const member in" } */