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[COMMITTED] ada: Fix crash on vector initialization

Message ID 20230529082921.2410077-1-poulhies@adacore.com
State Committed
Commit 8196b58e0a1a466a41d2fd2f3c6eb3f6ee68685c
Headers
Series [COMMITTED] ada: Fix crash on vector initialization |

Commit Message

Marc Poulhiès May 29, 2023, 8:29 a.m. UTC 
  Initializing a vector using

 Vec : V.Vector := [Some_Type'(Some_Abstract_Type with F => 0)];

may crash the compiler. The expander marks the N_Extension_Aggregate for
delayed expansion which never happens and incorrectly ends up in gigi.

The delayed expansion is needed for nested aggregates, which the
original code is testing for, but container aggregates are handled
differently.

Such assignments to container aggregates are later transformed into
procedure calls to the procedures named in the Aggregate aspect
definition, for which the delayed expansion is not required/expected.

gcc/ada/

	* exp_aggr.adb (Convert_To_Assignments): Do not mark node for
	delayed expansion if parent type has the Aggregate aspect.
	* sem_util.adb (Is_Container_Aggregate): Move...
	* sem_util.ads (Is_Container_Aggregate): ... here and make it
	public.

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

---
 gcc/ada/exp_aggr.adb | 7 +++++--
 gcc/ada/sem_util.adb | 3 ---
 gcc/ada/sem_util.ads | 3 +++
 3 files changed, 8 insertions(+), 5 deletions(-)

Comments

Eric Botcazou July 7, 2023, 8:49 a.m. UTC | #1 
> Such assignments to container aggregates are later transformed into
> procedure calls to the procedures named in the Aggregate aspect
> definition, for which the delayed expansion is not required/expected.
> 
> gcc/ada/
> 
> 	* exp_aggr.adb (Convert_To_Assignments): Do not mark node for
> 	delayed expansion if parent type has the Aggregate aspect.
> 	* sem_util.adb (Is_Container_Aggregate): Move...
> 	* sem_util.ads (Is_Container_Aggregate): ... here and make it
> 	public.

This is not a regression but the problem is quite visible in Ada 2022 so I 
backported the fix onto the 13 branch.
diff mbox series

Patch

diff --git a/gcc/ada/exp_aggr.adb b/gcc/ada/exp_aggr.adb
index a6a7d810185..75e5e1402df 100644
--- a/gcc/ada/exp_aggr.adb
+++ b/gcc/ada/exp_aggr.adb
@@ -5000,9 +5000,12 @@  package body Exp_Aggr is
 
       if
          --  Internal aggregate (transformed when expanding the parent)
+         --  excluding the Container aggregate as these are transformed to
+         --  procedure call later.
 
-         Parent_Kind in
-           N_Aggregate | N_Extension_Aggregate | N_Component_Association
+         (Parent_Kind in
+            N_Component_Association | N_Aggregate | N_Extension_Aggregate
+            and then not Is_Container_Aggregate (Parent_Node))
 
          --  Allocator (see Convert_Aggr_In_Allocator)
 
diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb
index 64abfb11ce5..a42b2dff60f 100644
--- a/gcc/ada/sem_util.adb
+++ b/gcc/ada/sem_util.adb
@@ -132,9 +132,6 @@  package body Sem_Util is
    --  Determine whether arbitrary entity Id denotes an atomic object as per
    --  RM C.6(7).
 
-   function Is_Container_Aggregate (Exp : Node_Id) return Boolean;
-   --  Is the given expression a container aggregate?
-
    generic
       with function Is_Effectively_Volatile_Entity
         (Id : Entity_Id) return Boolean;
diff --git a/gcc/ada/sem_util.ads b/gcc/ada/sem_util.ads
index b5bcd267e33..d1bbc6af0e8 100644
--- a/gcc/ada/sem_util.ads
+++ b/gcc/ada/sem_util.ads
@@ -1475,6 +1475,9 @@  package Sem_Util is
    --  Return True if the loop has no side effect and can therefore be
    --  marked for removal. Return False if N is not a N_Loop_Statement.
 
+   function Is_Container_Aggregate (Exp : Node_Id) return Boolean;
+   --  Is the given expression a container aggregate?
+
    function Is_Newly_Constructed
      (Exp : Node_Id; Context_Requires_NC : Boolean) return Boolean;
    --  Indicates whether a given expression is "newly constructed" (RM 4.4).