Commit 2a35a4ca by Ed Schonberg Committed by Pierre-Marie de Rodat

[Ada] Static predicate check on characters of a string literal

This patch implements the rule given in R< 4.2 (11): if the component type of
a string literal is a character type with a static predicate, that predicate
must be applied to each character in the string.

Compiling the example below must yield:

   gcc -c -gnata main.adb

  main.adb:4:23: warning: static expression fails static predicate check on "C"
  main.adb:4:23: warning: expression is no longer considered static
  main.adb:4:24: warning: static expression fails static predicate check on "C"
  main.adb:4:24: warning: expression is no longer considered static
  main.adb:4:25: warning: static expression fails static predicate check on "C"
  main.adb:4:25: warning: expression is no longer considered static

Execution must yield:

  raised SYSTEM.ASSERTIONS.ASSERT_FAILURE :
                                        Static_Predicate failed at main.adb:4
----

procedure Main is
   subtype C is Character with Static_Predicate => C in 'A' | 'B' | 'C';
   type S is array (Positive range <>) of C;
   X : constant S := "abc";
begin
   null;
end;

2018-05-31  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* sem_res.adb (Resolve_String_Literal): If the type is a string type
	whose component subtype has a static predicate, ensure that the
	predicate is applied to each character by expanding the string into the
	equivalent aggregate. This is also done if the component subtype is
	constrained.

From-SVN: r261014
parent d9898483
2018-05-31 Ed Schonberg <schonberg@adacore.com>
* sem_res.adb (Resolve_String_Literal): If the type is a string type
whose component subtype has a static predicate, ensure that the
predicate is applied to each character by expanding the string into the
equivalent aggregate. This is also done if the component subtype is
constrained.
2018-05-31 Eric Botcazou <ebotcazou@adacore.com>
* gcc-interface/trans.c (Call_to_gnu): Remove obsolete code.
......
......@@ -10774,7 +10774,9 @@ package body Sem_Res is
-- whether the evaluation of the string will raise constraint error.
-- Otherwise we need to transform the string literal into the
-- corresponding character aggregate and let the aggregate code do
-- the checking.
-- the checking. We use the same transformation if the component
-- type has a static predicate, which will be applied to each
-- character when the aggregate is resolved.
if Is_Standard_Character_Type (R_Typ) then
......@@ -10811,7 +10813,9 @@ package body Sem_Res is
end if;
end loop;
return;
if not Has_Static_Predicate (C_Typ) then
return;
end if;
end if;
end;
end if;
......
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