[Ada] No Storage_Error for an oversized disabled ghost array object

[Ada] No Storage_Error for an oversized disabled ghost array object

[Pierre-Marie de Rodat]

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In some cases where the size computation for an object declaration will
unconditionally overflow, the FE generates code to raise Storage_Error
at the point of the object declaration (and may generate an associated
warning). Don't do this if the object declaration is an ignored (i.e.,
disabled) ghost declaration.

Tested on x86_64-pc-linux-gnu, committed on trunk

2019-09-18  Steve Baird  <baird@adacore.com>

gcc/ada/

	* freeze.adb (Freeze_Object_Declaration): Do not call
	Check_Large_Modular_Array when the object declaration being
	frozen is an ignored ghost entity.

gcc/testsuite/

	* gnat.dg/ghost7.adb, gnat.dg/ghost7.ads: New testcase.

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--- gcc/ada/freeze.adb
+++ gcc/ada/freeze.adb
@@ -3569,7 +3569,8 @@ package body Freeze is
             Error_Msg_N ("\??use explicit size clause to set size", E);
          end if;
 
-         if Is_Array_Type (Typ) then
+         --  Declaring a too-big array in disabled ghost code is OK
+         if Is_Array_Type (Typ) and then not Is_Ignored_Ghost_Entity (E) then
             Check_Large_Modular_Array (Typ);
          end if;
       end Freeze_Object_Declaration;

--- /dev/null
new file mode 100644
+++ gcc/testsuite/gnat.dg/ghost7.adb
@@ -0,0 +1,6 @@
+--  { dg-do compile }
+--  { dg-options "-gnatwa" }
+
+package body Ghost7 is
+   procedure Dummy is null;
+end Ghost7;

--- /dev/null
new file mode 100644
+++ gcc/testsuite/gnat.dg/ghost7.ads
@@ -0,0 +1,8 @@
+pragma Restrictions (No_Exception_Propagation);
+
+package Ghost7 is
+   type Word64 is mod 2**64;
+   type My_Array_Type is array (Word64) of Boolean;
+   My_Array : My_Array_Type with Ghost;
+   procedure Dummy;
+end Ghost7;
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