From 2bf492a1a4526f143064e41001f34fc1874feea7 Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Mon, 20 Oct 2014 13:29:02 -0400
Subject: [PATCH] re PR c++/63601 (Segfault on usage of 'this' in unevaluated
 context inside lambda)

	PR c++/63601
	* lambda.c (current_nonlambda_function): New.
	* semantics.c (finish_this_expr): Use it.
	* cp-tree.h: Declare it.

From-SVN: r216488
---
 gcc/cp/ChangeLog                              |  7 +++++
 gcc/cp/cp-tree.h                              |  1 +
 gcc/cp/lambda.c                               | 11 +++++++
 gcc/cp/semantics.c                            | 30 ++++++++-----------
 .../g++.dg/cpp0x/lambda/lambda-this20.C       |  4 +++
 5 files changed, 35 insertions(+), 18 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-this20.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 1148e9566ad..e61ae2bfa83 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2014-10-20  Jason Merrill  <jason@redhat.com>
+
+	PR c++/63601
+	* lambda.c (current_nonlambda_function): New.
+	* semantics.c (finish_this_expr): Use it.
+	* cp-tree.h: Declare it.
+
 2014-10-17  Alan Modra  <amodra@gmail.com>
 
 	PR middle-end/61848
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index b6afc311fe0..0923d9f0f7c 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -5961,6 +5961,7 @@ extern bool is_normal_capture_proxy             (tree);
 extern void register_capture_members		(tree);
 extern tree lambda_expr_this_capture            (tree, bool);
 extern tree maybe_resolve_dummy			(tree, bool);
+extern tree current_nonlambda_function		(void);
 extern tree nonlambda_method_basetype		(void);
 extern void maybe_add_lambda_conv_op            (tree);
 extern bool is_lambda_ignored_entity            (tree);
diff --git a/gcc/cp/lambda.c b/gcc/cp/lambda.c
index 17fd0377eb9..d4030e332e7 100644
--- a/gcc/cp/lambda.c
+++ b/gcc/cp/lambda.c
@@ -777,6 +777,17 @@ maybe_resolve_dummy (tree object, bool add_capture_p)
   return object;
 }
 
+/* Returns the innermost non-lambda function.  */
+
+tree
+current_nonlambda_function (void)
+{
+  tree fn = current_function_decl;
+  while (fn && LAMBDA_FUNCTION_P (fn))
+    fn = decl_function_context (fn);
+  return fn;
+}
+
 /* Returns the method basetype of the innermost non-lambda function, or
    NULL_TREE if none.  */
 
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 0e675a3a3f2..26e66f512cf 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -2438,7 +2438,7 @@ finish_increment_expr (tree expr, enum tree_code code)
 tree
 finish_this_expr (void)
 {
-  tree result;
+  tree result = NULL_TREE;
 
   if (current_class_ptr)
     {
@@ -2450,25 +2450,19 @@ finish_this_expr (void)
       else
         result = current_class_ptr;
     }
-  else if (current_function_decl
-	   && DECL_STATIC_FUNCTION_P (current_function_decl))
-    {
-      error ("%<this%> is unavailable for static member functions");
-      result = error_mark_node;
-    }
-  else
-    {
-      if (current_function_decl)
-	error ("invalid use of %<this%> in non-member function");
-      else
-	error ("invalid use of %<this%> at top level");
-      result = error_mark_node;
-    }
 
-  /* The keyword 'this' is a prvalue expression.  */
-  result = rvalue (result);
+  if (result)
+    /* The keyword 'this' is a prvalue expression.  */
+    return rvalue (result);
 
-  return result;
+  tree fn = current_nonlambda_function ();
+  if (fn && DECL_STATIC_FUNCTION_P (fn))
+    error ("%<this%> is unavailable for static member functions");
+  else if (fn)
+    error ("invalid use of %<this%> in non-member function");
+  else
+    error ("invalid use of %<this%> at top level");
+  return error_mark_node;
 }
 
 /* Finish a pseudo-destructor expression.  If SCOPE is NULL, the
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-this20.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-this20.C
new file mode 100644
index 00000000000..0d273202bfb
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-this20.C
@@ -0,0 +1,4 @@
+// PR c++/63601
+// { dg-do compile { target c++11 } }
+
+auto f = []{ sizeof(this); };	// { dg-error "this" }
-- 
2.30.2