[Ada] Remove redundant guard from Find_Overlaid_Entity

Message ID 20210615102052.GA3288@adacore.com
State New
Headers show
Series
  • [Ada] Remove redundant guard from Find_Overlaid_Entity
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Commit Message

Pierre-Marie de Rodat June 15, 2021, 10:20 a.m.
The comment for Find_Overlaid_Entity which says "node N should be an
address representation clause" is now enforced with an assertion. A
defensive code is removed from the body; the defensive code at the
callers of this routine is enough to prevent crashes.

Code cleanup related to improved handling of overlays in SPARK.

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

gcc/ada/

	* sem_util.ads (Find_Overlaid_Entity): Simplify comment for
	spec.
	* sem_util.adb (Find_Overlaid_Entity): Remove defensive code
	from body.

Patch

diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb
--- a/gcc/ada/sem_util.adb
+++ b/gcc/ada/sem_util.adb
@@ -9371,6 +9371,10 @@  package body Sem_Util is
       Ent : out Entity_Id;
       Off : out Boolean)
    is
+      pragma Assert
+        (Nkind (N) = N_Attribute_Definition_Clause
+         and then Chars (N) = Name_Address);
+
       Expr : Node_Id;
 
    begin
@@ -9390,61 +9394,56 @@  package body Sem_Util is
       Ent := Empty;
       Off := False;
 
-      if Nkind (N) = N_Attribute_Definition_Clause
-        and then Chars (N) = Name_Address
-      then
-         Expr := Expression (N);
+      Expr := Expression (N);
 
-         --  This loop checks the form of the expression for Y'Address,
-         --  using recursion to deal with intermediate constants.
+      --  This loop checks the form of the expression for Y'Address, using
+      --  recursion to deal with intermediate constants.
 
-         loop
-            --  Check for Y'Address
+      loop
+         --  Check for Y'Address
 
-            if Nkind (Expr) = N_Attribute_Reference
-              and then Attribute_Name (Expr) = Name_Address
-            then
-               Expr := Prefix (Expr);
-               exit;
+         if Nkind (Expr) = N_Attribute_Reference
+           and then Attribute_Name (Expr) = Name_Address
+         then
+            Expr := Prefix (Expr);
+            exit;
 
-            --  Check for Const where Const is a constant entity
+         --  Check for Const where Const is a constant entity
 
-            elsif Is_Entity_Name (Expr)
-              and then Ekind (Entity (Expr)) = E_Constant
-            then
-               Expr := Constant_Value (Entity (Expr));
+         elsif Is_Entity_Name (Expr)
+           and then Ekind (Entity (Expr)) = E_Constant
+         then
+            Expr := Constant_Value (Entity (Expr));
 
-            --  Anything else does not need checking
+         --  Anything else does not need checking
 
-            else
-               return;
-            end if;
-         end loop;
+         else
+            return;
+         end if;
+      end loop;
 
-         --  This loop checks the form of the prefix for an entity, using
-         --  recursion to deal with intermediate components.
+      --  This loop checks the form of the prefix for an entity, using
+      --  recursion to deal with intermediate components.
 
-         loop
-            --  Check for Y where Y is an entity
+      loop
+         --  Check for Y where Y is an entity
 
-            if Is_Entity_Name (Expr) then
-               Ent := Entity (Expr);
-               return;
+         if Is_Entity_Name (Expr) then
+            Ent := Entity (Expr);
+            return;
 
-            --  Check for components
+         --  Check for components
 
-            elsif Nkind (Expr) in N_Selected_Component | N_Indexed_Component
-            then
-               Expr := Prefix (Expr);
-               Off := True;
+         elsif Nkind (Expr) in N_Selected_Component | N_Indexed_Component then
+            Expr := Prefix (Expr);
+            Off  := True;
 
-            --  Anything else does not need checking
+         --  Anything else does not need checking
 
-            else
-               return;
-            end if;
-         end loop;
-      end if;
+         else
+            return;
+         end if;
+      end loop;
    end Find_Overlaid_Entity;
 
    -------------------------


diff --git a/gcc/ada/sem_util.ads b/gcc/ada/sem_util.ads
--- a/gcc/ada/sem_util.ads
+++ b/gcc/ada/sem_util.ads
@@ -900,12 +900,11 @@  package Sem_Util is
      (N   : Node_Id;
       Ent : out Entity_Id;
       Off : out Boolean);
-   --  The node N should be an address representation clause. Determines if
-   --  the target expression is the address of an entity with an optional
-   --  offset. If so, set Ent to the entity and, if there is an offset, set
-   --  Off to True, otherwise to False. If N is not an address representation
-   --  clause, or if it is not possible to determine that the address is of
-   --  this form, then set Ent to Empty.
+   --  The node N should be an address representation clause. Determines if the
+   --  target expression is the address of an entity with an optional offset.
+   --  If so, set Ent to the entity and, if there is an offset, set Off to
+   --  True, otherwise to False. If it is not possible to determine that the
+   --  address is of this form, then set Ent to Empty.
 
    function Find_Parameter_Type (Param : Node_Id) return Entity_Id;
    --  Return the type of formal parameter Param as determined by its