From: Gary Dismukes <dismu...@adacore.com>
If a type DT is derived from a record type T with convention C_Pass_By_Copy
and explicitly specifies convention C (via aspect or pragma), then type DT
should not be treated as a type with convention C_Pass_By_Copy. Any parameters
of the derived type should be passed by reference rather than by copy. The
compiler was incorrectly inheriting convention C_Pass_By_Copy, by inheriting
the flag set on the parent type, but that flag needs to be unset in the case
where the convention is overridden.
gcc/ada/
* sem_prag.adb (Set_Convention_From_Pragma): If the specified
convention on
a record type is not C_Pass_By_Copy, then force the C_Pass_By_Copy flag
to
False, to ensure that it's overridden.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/sem_prag.adb | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/gcc/ada/sem_prag.adb b/gcc/ada/sem_prag.adb
index 9ccf1b9cf65..671b2a542ea 100644
--- a/gcc/ada/sem_prag.adb
+++ b/gcc/ada/sem_prag.adb
@@ -8498,6 +8498,15 @@ package body Sem_Prag is
end if;
end if;
+ -- If the convention of a record type is changed (such as to C),
+ -- this must override C_Pass_By_Copy if that flag was inherited
+ -- from a parent type where the latter convention was specified,
+ -- so we force the flag to False.
+
+ if Cname /= Name_C_Pass_By_Copy and then Is_Record_Type (E) then
+ Set_C_Pass_By_Copy (Base_Type (E), False);
+ end if;
+
-- If the entity is a derived boolean type, check for the special
-- case of convention C, C++, or Fortran, where we consider any
-- nonzero value to represent true.
--
2.45.1
