From: Eric Botcazou <ebotca...@adacore.com>
In Ada 2012, the compiler fails to check that a primitive equality operator
for an untagged record type must appear before the type is frozen, when the
operator returns a subtype of Boolean. This plugs the legality loophole but
adds the debug switch -gnatd_q to go back to the previous state.
gcc/ada/ChangeLog:
PR ada/18765
* debug.adb (d_q): Document new usage.
* sem_ch6.adb (New_Overloaded_Entity): Apply the special processing
to all equality operators whose base result type is Boolean, but do
not enforce the new Ada 2012 freezing rule if the result type is a
proper subtype of it and the -gnatd_q switch is specified.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/debug.adb | 6 +++++-
gcc/ada/sem_ch6.adb | 12 ++++++++++--
2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/gcc/ada/debug.adb b/gcc/ada/debug.adb
index 7b95fa87f02..ac3ce41dcc5 100644
--- a/gcc/ada/debug.adb
+++ b/gcc/ada/debug.adb
@@ -154,7 +154,7 @@ package body Debug is
-- d_n
-- d_o
-- d_p Ignore assertion pragmas for elaboration
- -- d_q
+ -- d_q Do not enforce freezing for equality operator of boolean subtype
-- d_r Disable the use of the return slot in functions
-- d_s Stop elaboration checks on synchronous suspension
-- d_t In LLVM-based CCG, dump LLVM IR after transformations are done
@@ -999,6 +999,10 @@ package body Debug is
-- semantics of invariants and postconditions in both the static and
-- dynamic elaboration models.
+ -- d_q The compiler does not enforce the new freezing rule introduced for
+ -- primitive equality operators in Ada 2012 when the operator returns
+ -- a subtype of Boolean.
+
-- d_r The compiler does not make use of the return slot in the expansion
-- of functions returning a by-reference type. If this use is required
-- for these functions to return on the primary stack, then they are
diff --git a/gcc/ada/sem_ch6.adb b/gcc/ada/sem_ch6.adb
index 49d83f8d5e0..80e0c9c634c 100644
--- a/gcc/ada/sem_ch6.adb
+++ b/gcc/ada/sem_ch6.adb
@@ -12880,12 +12880,20 @@ package body Sem_Ch6 is
<<Check_Inequality>>
if Chars (S) = Name_Op_Eq
- and then Etype (S) = Standard_Boolean
+ and then Base_Type (Etype (S)) = Standard_Boolean
and then Present (Parent (S))
and then not Is_Dispatching_Operation (S)
then
Make_Inequality_Operator (S);
- Check_Untagged_Equality (S);
+
+ -- The freezing rule introduced in Ada 2012 was historically
+ -- not enforced for operators returning a subtype of Boolean.
+
+ if Etype (S) = Standard_Boolean
+ or else not Debug_Flag_Underscore_Q
+ then
+ Check_Untagged_Equality (S);
+ end if;
end if;
end New_Overloaded_Entity;
--
2.43.0
