2010-10-04 Vincent Celier <celier@adacore.com>

	* a-direct.adb (Copy_File): Interpret the Form parameter and call
	System.OS_Lib.Copy_File to do the work accordingly. Raise Use_Error if
	the Form parameter contains an incorrect value for field preserve= or
	mode=.
	* a-direct.ads (Create_Directory, Create_Path): Indicate that the Form
	parameter is ignored.
	(Copy_File): Indicate the interpretation of the Form parameter.

2010-10-04  Vincent Celier  <celier@adacore.com>

	* make.adb (Gnatmake): When there are no foreign languages declared and
	a main in attribute Main of the main project does not exist or is a
	source of another project, fail immediately before attempting
	compilation.

2010-10-04  Javier Miranda  <miranda@adacore.com>

	* exp_disp.ads (Convert_Tag_To_Interface): New function which must be
	used to convert a node referencing a tag to a class-wide interface type.
	* exp_disp.adb (Convert_Tag_To_Interface): New function.
	(Expand_Interface_Conversion): Replace invocation of
	Unchecked_Conversion by new function Convert_Tag_To_Interface.
	(Write_DT): Add support for null primitives.
	* exp_ch3.adb (Expand_N_Object_Declaration): For tagged type objects,
	cleanup code that handles interface conversions and avoid unchecked
	conversion of referenced tag components.
	* exp_ch5.adb (Expand_N_Assignment_Statement): Code cleanup. Avoid
	unrequired conversions when generating a dispatching call to _assign.
	* sprint.adb (Write_Itype): Fix wrong output of not null access itypes.

2010-10-04  Ed Schonberg  <schonberg@adacore.com>

	* exp_ch4.adb (Expand_N_Op_Not): Handle properly both operands when the
	parent is a binary boolean operation and the operand is an unpacked
	array.
	(Build_Boolean_Array_Proc_Call): If the operands are both negations, the
	operands of the rewritten node are the operands of the negations, not
	the negations themselves.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@164942 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 27 insertions, 0 deletions

diff --git a/gcc/ada/exp_disp.ads b/gcc/ada/exp_disp.ads
index 5c3796ba410..823693ba492 100644
--- a/gcc/ada/exp_disp.ads
+++ b/gcc/ada/exp_disp.ads
@@ -186,6 +186,33 @@ package Exp_Disp is
    --  bodies they are added to the end of the list of declarations of the
    --  package body.
 
+   function Convert_Tag_To_Interface
+     (Typ : Entity_Id; Expr : Node_Id) return Node_Id;
+   pragma Inline (Convert_Tag_To_Interface);
+   --  This function is used in class-wide interface conversions; the expanded
+   --  code generated to convert a tagged object to a class-wide interface type
+   --  involves referencing the tag component containing the secondary dispatch
+   --  table associated with the interface. Given the expression Expr that
+   --  references a tag component, we cannot generate an unchecked conversion
+   --  to leave the expression decorated with the class-wide interface type Typ
+   --  because an unchecked conversion cannot be seen as a no-op. An unchecked
+   --  conversion is conceptually a function call and therefore the RM allows
+   --  the backend to obtain a copy of the value of the actual object and store
+   --  it in some other place (like a register); in such case the interface
+   --  conversion is not equivalent to a displacement of the pointer to the
+   --  interface and any further displacement fails. Although the functionality
+   --  of this function is simple and could be done directly, the purpose of
+   --  this routine is to leave well documented in the sources these
+   --  occurrences.
+
+   --  If Expr is an N_Selected_Component that references a tag generate:
+   --     type ityp is non null access Typ;
+   --     ityp!(Expr'Address).all
+
+   --  if Expr is an N_Function_Call to Ada.Tags.Displace then generate:
+   --     type ityp is non null access Typ;
+   --     ityp!(Expr).all
+
    function CPP_Num_Prims (Typ : Entity_Id) return Nat;
    --  Return the number of primitives of the C++ part of the dispatch table.
    --  For types that are not derivations of CPP types return 0.