From: Jason Merrill <jason@redhat.com>
Date: Thu, 13 Oct 2011 18:03:06 +0000 (-0400)
Subject: re PR c++/50618 (Virtual inheritance segfault)
X-Git-Tag: releases/gcc-4.4.7~213
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7cb3890d6ef4d16958a9f763d592320b831491f7;p=thirdparty%2Fgcc.git

re PR c++/50618 (Virtual inheritance segfault)

	PR c++/50618
	* init.c (expand_aggr_init_1): Don't zero-initialize virtual
	bases of a base subobject.

From-SVN: r179938
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index a5a834187d4e..3797b3a7a270 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2011-10-13  Jason Merrill  <jason@redhat.com>
 
+	PR c++/50618
+	* init.c (expand_aggr_init_1): Don't zero-initialize virtual
+	bases of a base subobject.
+
 	Backported from 4.6 branch
 	2011-03-11  Jakub Jelinek  <jakub@redhat.com>
 
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index 4294acc80653..d219a4f176df 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -1443,7 +1443,12 @@ expand_aggr_init_1 (tree binfo, tree true_exp, tree exp, tree init, int flags,
 	 zero out the object first.  */
       else if (TYPE_NEEDS_CONSTRUCTING (type))
 	{
-	  init = build_zero_init (type, NULL_TREE, /*static_storage_p=*/false);
+	  tree field_size = NULL_TREE;
+	  if (exp != true_exp && CLASSTYPE_AS_BASE (type) != type)
+	    /* Don't clobber already initialized virtual bases.  */
+	    field_size = TYPE_SIZE (CLASSTYPE_AS_BASE (type));
+	  init = build_zero_init_1 (type, NULL_TREE, /*static_storage_p=*/false,
+				    field_size);
 	  init = build2 (INIT_EXPR, type, exp, init);
 	  finish_expr_stmt (init);
 	  /* And then call the constructor.  */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 3fe28e698bbf..8ccbd7ebc5ce 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2011-10-13  Jason Merrill  <jason@redhat.com>
 
+	PR c++/50618
+	* g++.dg/init/vbase1.C: New.
+
 	Backported from 4.6 branch
 	2011-03-11  Jakub Jelinek  <jakub@redhat.com>
 
diff --git a/gcc/testsuite/g++.dg/init/vbase1.C b/gcc/testsuite/g++.dg/init/vbase1.C
new file mode 100644
index 000000000000..bbfd58f5c348
--- /dev/null
+++ b/gcc/testsuite/g++.dg/init/vbase1.C
@@ -0,0 +1,39 @@
+// PR c++/50618
+// { dg-do run }
+
+struct Base
+{
+    const int text;
+    Base():text(1) {}
+    Base(int aText)
+    : text(aText) {}
+};
+struct SubA : public virtual Base
+{
+protected:
+  int x;
+public:
+  SubA(int aX)
+  : x(aX) {}
+};
+class SubB : public virtual Base
+{};
+struct Diamond : public SubA, public SubB
+{
+    Diamond(int text)
+    : Base(text), SubA(5), SubB() {}
+
+    void printText()
+    {
+        if(text != 2)
+          __builtin_abort();
+        if(x!=5)
+          __builtin_abort();
+    }
+};
+
+int main(int, char**)
+{
+    Diamond x(2);
+    x.printText();
+}