From: "Marc Poulhiès" <poulhies@adacore.com>
To: gcc-patches@gcc.gnu.org
Cc: Steve Baird <baird@adacore.com>
Subject: [COMMITTED] ada: Improve handling of declare expressions in deferred-freezing contexts
Date: Tue, 8 Nov 2022 09:42:44 +0100 [thread overview]
Message-ID: <20221108084244.301581-1-poulhies@adacore.com> (raw)
From: Steve Baird <baird@adacore.com>
In some cases where a declare expression occurs in a deferred-freezing
context (e.g., within the default value for a discriminant or for a formal
parameter, or within the expression of an expression function), the compiler
generates a bugbox.
gcc/ada/
* sem_ch3.adb
(Analyze_Object_Declaration): Do not perform expansion actions if
In_Spec_Expression is true.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/sem_ch3.adb | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/gcc/ada/sem_ch3.adb b/gcc/ada/sem_ch3.adb
index 8f4e9f80eb8..95ffbe00ba4 100644
--- a/gcc/ada/sem_ch3.adb
+++ b/gcc/ada/sem_ch3.adb
@@ -4721,6 +4721,26 @@ package body Sem_Ch3 is
Expand_Sliding_Conversion (E, T);
end if;
+ if In_Spec_Expression and then In_Declare_Expr > 0 then
+ -- It is too early to be doing expansion-ish things,
+ -- so exit early. But we have to set Ekind (Id) now so
+ -- that subsequent uses of this entity are not rejected
+ -- via the same mechanism that (correctly) rejects
+ -- "X : Integer := X;".
+
+ if Constant_Present (N) then
+ Mutate_Ekind (Id, E_Constant);
+ Set_Is_True_Constant (Id);
+ else
+ Mutate_Ekind (Id, E_Variable);
+ if Present (E) then
+ Set_Has_Initial_Value (Id);
+ end if;
+ end if;
+
+ goto Leave;
+ end if;
+
Expand_Subtype_From_Expr
(N => N,
Unc_Type => T,
--
2.34.1
reply other threads:[~2022-11-08 8:42 UTC|newest]
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