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[COMMITTED] ada: Compiler crash on early alignment clause

Message ID 20231107092045.3906982-1-poulhies@adacore.com
State Accepted
Headers
Series [COMMITTED] ada: Compiler crash on early alignment clause |

Checks

Context Check Description
snail/gcc-patch-check success Github commit url

Commit Message

Marc Poulhiès Nov. 7, 2023, 9:20 a.m. UTC 
  From: Bob Duff <duff@adacore.com>

This patch fixes a bug: if "for T'Alignment use..." is followed
by "for T use (<enum rep>);" the compiler crashes. A workaround is
to move the alignment clause after the enumeration rep clause.

gcc/ada/

	* sem_ch13.ads (Set_Enum_Esize): Do not set alignment.
	* sem_ch13.adb (Set_Enum_Esize): Do not set alignment. Archaeology
	seems to show that this line of code dates from when "Alignment =
	0" meant "the Alignment is not known at compile time" and "the
	Alignment is not yet known at compile time" as well as "the
	Alignment is zero". In any case, it seems to be unnecessary, and
	in this case harmful, because gigi would crash. Alignment_Clause
	is set (because there is one), so gigi would query the Alignment,
	but Alignment was destroyed.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/sem_ch13.adb | 2 --
 gcc/ada/sem_ch13.ads | 3 +--
 2 files changed, 1 insertion(+), 4 deletions(-)
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Patch

diff --git a/gcc/ada/sem_ch13.adb b/gcc/ada/sem_ch13.adb
index 5747ee9c539..302fab74757 100644
--- a/gcc/ada/sem_ch13.adb
+++ b/gcc/ada/sem_ch13.adb
@@ -17381,8 +17381,6 @@  package body Sem_Ch13 is
       Sz : Unat;
 
    begin
-      Reinit_Alignment (T);
-
       --  Find the minimum standard size (8,16,32,64,128) that fits
 
       Lo := Enumeration_Rep (Entity (Type_Low_Bound (T)));
diff --git a/gcc/ada/sem_ch13.ads b/gcc/ada/sem_ch13.ads
index 1386096535e..555d302fb10 100644
--- a/gcc/ada/sem_ch13.ads
+++ b/gcc/ada/sem_ch13.ads
@@ -79,8 +79,7 @@  package Sem_Ch13 is
    procedure Set_Enum_Esize (T : Entity_Id);
    --  This routine sets the Esize field for an enumeration type T, based
    --  on the current representation information available for T. Note that
-   --  the setting of the RM_Size field is not affected. This routine also
-   --  initializes the alignment field to zero.
+   --  the setting of the RM_Size field is not affected.
 
    Unknown_Minimum_Size : constant Nonzero_Int := -1;