decl.c (gnat_to_gnu_param): Add comment about double reference and DECL_POINTS_TO_REA...

	* gcc-interface/decl.c (gnat_to_gnu_param): Add comment about double
	reference and DECL_POINTS_TO_READONLY_P.
	* gcc-interface/trans.c (Identifier_to_gnu) <by_ref>: Always set the
	TREE_READONLY flag on the first dereference of a double dereference.

From-SVN: r182460

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index 5c936f2fc6a8798e35dda52283415c9bf7324b42..0533f9cfd4cdaf85aeb1586ee925c1ced02cfca0 100644 (file)
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,10 @@
+2011-12-18  Eric Botcazou  <ebotcazou@adacore.com>
+
+       * gcc-interface/decl.c (gnat_to_gnu_param): Add comment about double
+       reference and DECL_POINTS_TO_READONLY_P.
+       * gcc-interface/trans.c (Identifier_to_gnu) <by_ref>: Always set the
+       TREE_READONLY flag on the first dereference of a double dereference.
+
 2011-12-15  Arnaud Charlet  <charlet@adacore.com>
 
        * a-numaux-vms.ads, s-asthan-vms-ia64.adb, s-auxdec-vms-ia64.adb,

diff --git a/gcc/ada/gcc-interface/decl.c b/gcc/ada/gcc-interface/decl.c
index c3774f2a6ba50963853c0eb3daef166610eac85e..89a6a2ea2cc236a5af6db2f3922054d9d48cc87f 100644 (file)
--- a/gcc/ada/gcc-interface/decl.c
+++ b/gcc/ada/gcc-interface/decl.c
@@ -5587,6 +5587,10 @@ gnat_to_gnu_param (Entity_Id gnat_param, Mechanism_Type mech,
   DECL_BY_COMPONENT_PTR_P (gnu_param) = by_component_ptr;
   DECL_BY_DESCRIPTOR_P (gnu_param) = (mech == By_Descriptor ||
                                       mech == By_Short_Descriptor);
+  /* Note that, in case of a parameter passed by double reference, the
+     DECL_POINTS_TO_READONLY_P flag is meant for the second reference.
+     The first reference always points to read-only, as it points to
+     the second reference, i.e. the reference to the actual parameter.  */
   DECL_POINTS_TO_READONLY_P (gnu_param)
     = (ro_param && (by_ref || by_component_ptr));
   DECL_CAN_NEVER_BE_NULL_P (gnu_param) = Can_Never_Be_Null (gnat_param);

diff --git a/gcc/ada/gcc-interface/trans.c b/gcc/ada/gcc-interface/trans.c
index da1a8f1f4ee7dabd8027322e18a7e479991b865c..3640782dbc0658c12dad21b48cb4d4a3dac3f06c 100644 (file)
--- a/gcc/ada/gcc-interface/trans.c
+++ b/gcc/ada/gcc-interface/trans.c
@@ -1038,8 +1038,9 @@ Identifier_to_gnu (Node_Id gnat_node, tree *gnu_result_type_p)
          if (TREE_CODE (gnu_result) == INDIRECT_REF)
            TREE_THIS_NOTRAP (gnu_result) = 1;
 
-         if (read_only)
-           TREE_READONLY (gnu_result) = 1;
+         /* The first reference, in case of a double reference, always points
+            to read-only, see gnat_to_gnu_param for the rationale.  */
+         TREE_READONLY (gnu_result) = 1;
        }
 
       /* If it's a PARM_DECL to foreign convention subprogram, convert it.  */