From c6989fbbf2f195e874245409635a856d74bf6945 Mon Sep 17 00:00:00 2001
From: Gary Dismukes <dismukes@adacore.com>
Date: Wed, 8 Jan 2025 22:51:41 +0000
Subject: [PATCH] ada: Unbounded recursion on character aggregates with
predicated component subtype
The compiler was recursing endlessly when analyzing an aggregate of
an array type whose component subtype has a static predicate and the
component expressions are static, repeatedly transforming the aggregate
first into a string literal and then back into an aggregate. This is fixed
by suppressing the transformation to a string literal in the case where
the component subtype has predicates.
gcc/ada/ChangeLog:
* sem_aggr.adb (Resolve_Aggregate): Add another condition to prevent rewriting
an aggregate whose type is an array of characters, testing for the presence of
predicates on the component type.
---
gcc/ada/sem_aggr.adb | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/gcc/ada/sem_aggr.adb b/gcc/ada/sem_aggr.adb
index 095093cc76bd..f6db5cb97a4a 100644
--- a/gcc/ada/sem_aggr.adb
+++ b/gcc/ada/sem_aggr.adb
@@ -1382,11 +1382,11 @@ package body Sem_Aggr is
-- Do not perform this transformation if this was a string literal
-- to start with, whose components needed constraint checks, or if
- -- the component type is non-static, because it will require those
- -- checks and be transformed back into an aggregate. If the index
- -- type is not Integer the aggregate may represent a user-defined
- -- string type but the context might need the original type so we
- -- do not perform the transformation at this point.
+ -- the component type is nonstatic or has predicates, because it will
+ -- require those checks and be transformed back into an aggregate.
+ -- If the index type is not Integer, then the aggregate may represent
+ -- a user-defined string type but the context might need the original
+ -- type, so we do not perform the transformation at this point.
if Number_Dimensions (Typ) = 1
and then Is_Standard_Character_Type (Component_Type (Typ))
@@ -1396,6 +1396,7 @@ package body Sem_Aggr is
and then not Is_Bit_Packed_Array (Typ)
and then Nkind (Original_Node (Parent (N))) /= N_String_Literal
and then Is_OK_Static_Subtype (Component_Type (Typ))
+ and then not Has_Predicates (Component_Type (Typ))
and then Base_Type (Etype (First_Index (Typ))) =
Base_Type (Standard_Integer)
and then not Has_Static_Empty_Array_Bounds (Typ)
--
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