From: Jason Merrill <jason@gcc.gnu.org>
Date: Thu, 6 Jul 2006 03:33:20 +0000 (-0400)
Subject: re PR c++/13983 (no warning on some non-POD struct with packed attribute)
X-Git-Tag: releases/gcc-4.0.4~554
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=11262a0553bd4912f1712a0a234aa9d622ed4f7e;p=thirdparty%2Fgcc.git

re PR c++/13983 (no warning on some non-POD struct with packed attribute)

        PR c++/13983
        PR c++/17519
        * stor-layout.c (finish_record_layout): Copy TYPE_PACKED to variants.
        * cp/class.c (check_field_decls): Check TYPE_PACKED after
        stripping array types.

From-SVN: r115220
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e1aeae105526..3a118e4fa763 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2006-07-05  Jason Merrill  <jason@redhat.com>
+
+	PR c++/13983
+	PR c++/17519
+	* stor-layout.c (finish_record_layout): Copy TYPE_PACKED to variants.
+
 2006-07-04  Peter O'Gorman  <peter@pogma.com>
 
 	* mklibgcc.in: chmod 644 before ranlib during install.
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 417266192695..2c88746868e4 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,16 @@
+2006-07-05  Jason Merrill  <jason@redhat.com>
+
+	PR c++/13983
+	PR c++/17519
+	* class.c (check_field_decls): Check TYPE_PACKED after
+	stripping array types.
+
+2006-07-05  Nathan Sidwell  <nathan@codesourcery.com>
+
+	PR c++/21166
+	* class.c (check_field_decls): Only set DECL_PACKED on a field
+	when its natural alignment is > BITS_PER_UNIT.
+
 2006-07-05  Jason Merrill  <jason@redhat.com>
 
 	PR c++/18681
diff --git a/gcc/cp/class.c b/gcc/cp/class.c
index 14e8728ca8e9..8066ec9f7fbd 100644
--- a/gcc/cp/class.c
+++ b/gcc/cp/class.c
@@ -2850,39 +2850,6 @@ check_field_decls (tree t, tree *access_decls,
 
       next = &TREE_CHAIN (x);
 
-      if (TREE_CODE (x) == FIELD_DECL)
-	{
-	  if (TYPE_PACKED (t))
-	    {
-	      if (!pod_type_p (TREE_TYPE (x)) && !TYPE_PACKED (TREE_TYPE (x)))
-		cp_warning_at
-		  ("ignoring packed attribute on unpacked non-POD field %q#D",
-		   x);
-	      else
-		DECL_PACKED (x) = 1;
-	    }
-
-	  if (DECL_C_BIT_FIELD (x) && integer_zerop (DECL_INITIAL (x)))
-	    /* We don't treat zero-width bitfields as making a class
-	       non-empty.  */
-	    ;
-	  else
-	    {
-	      tree element_type;
-
-	      /* The class is non-empty.  */
-	      CLASSTYPE_EMPTY_P (t) = 0;
-	      /* The class is not even nearly empty.  */
-	      CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
-	      /* If one of the data members contains an empty class,
-		 so does T.  */
-	      element_type = strip_array_types (type);
-	      if (CLASS_TYPE_P (element_type) 
-		  && CLASSTYPE_CONTAINS_EMPTY_CLASS_P (element_type))
-		CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
-	    }
-	}
-
       if (TREE_CODE (x) == USING_DECL)
 	{
 	  /* Prune the access declaration from the list of fields.  */
@@ -2979,6 +2946,34 @@ check_field_decls (tree t, tree *access_decls,
 
       type = strip_array_types (type);
 
+      if (TYPE_PACKED (t))
+	{
+	  if (!pod_type_p (type) && !TYPE_PACKED (type))
+	    warning
+	      (0,
+	       "ignoring packed attribute on unpacked non-POD field %q+#D",
+	       x);
+	  else if (TYPE_ALIGN (TREE_TYPE (x)) > BITS_PER_UNIT)
+	    DECL_PACKED (x) = 1;
+	}
+
+      if (DECL_C_BIT_FIELD (x) && integer_zerop (DECL_INITIAL (x)))
+	/* We don't treat zero-width bitfields as making a class
+	   non-empty.  */
+	;
+      else
+	{
+	  /* The class is non-empty.  */
+	  CLASSTYPE_EMPTY_P (t) = 0;
+	  /* The class is not even nearly empty.  */
+	  CLASSTYPE_NEARLY_EMPTY_P (t) = 0;
+	  /* If one of the data members contains an empty class,
+	     so does T.  */
+	  if (CLASS_TYPE_P (type)
+	      && CLASSTYPE_CONTAINS_EMPTY_CLASS_P (type))
+	    CLASSTYPE_CONTAINS_EMPTY_CLASS_P (t) = 1;
+	}
+
       /* This is used by -Weffc++ (see below). Warn only for pointers
 	 to members which might hold dynamic memory. So do not warn
 	 for pointers to functions or pointers to members.  */
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 44aeea826abb..78295c5f6f94 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -1418,6 +1418,8 @@ finalize_type_size (tree type)
 void
 finish_record_layout (record_layout_info rli, int free_p)
 {
+  tree variant;
+
   /* Compute the final size.  */
   finalize_record_size (rli);
 
@@ -1427,6 +1429,12 @@ finish_record_layout (record_layout_info rli, int free_p)
   /* Perform any last tweaks to the TYPE_SIZE, etc.  */
   finalize_type_size (rli->t);
 
+  /* Propagate TYPE_PACKED to variants.  With C++ templates,
+     handle_packed_attribute is too early to do this.  */
+  for (variant = TYPE_NEXT_VARIANT (rli->t); variant;
+       variant = TYPE_NEXT_VARIANT (variant))
+    TYPE_PACKED (variant) = TYPE_PACKED (rli->t);
+
   /* Lay out any static members.  This is done now because their type
      may use the record's type.  */
   while (rli->pending_statics)
diff --git a/gcc/testsuite/g++.dg/ext/packed10.C b/gcc/testsuite/g++.dg/ext/packed10.C
new file mode 100644
index 000000000000..c4bbb1462d99
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/packed10.C
@@ -0,0 +1,14 @@
+// PR c++/13983, c++/17519
+// The typedef and the array were causing us to miss that A<int> is
+// a packed type.
+
+template <class T>
+struct A {
+  A();
+} __attribute__((packed));
+
+typedef A<int> Ai;
+
+struct B {
+  Ai a[2];
+} __attribute__((packed));