From a0fa549732f1a6ab26c7b904472a8f7d241dae39 Mon Sep 17 00:00:00 2001 From: Ed Schonberg Date: Wed, 23 May 2018 10:22:35 +0000 Subject: [PATCH] [Ada] Crash on predicate involving qualified expression in instance This patch inhibits the generation of freeze nodes when pre-analyzing the domain of iteration of an Ada2012 loop that appears as a quantified expression in a predicate for an array type. This prevents a back-end abort on an invisible freeze node that would otherwise appear in an unexpanded code sequence. The following must compile quietly: ---- with Id_Manager; package My_Id_Manager is new Id_Manager (Max_Id_Type => 100_000, Max_Key_Count => 100); ---- generic Max_Id_Type : Positive; Max_Key_Count : Positive; package Id_Manager is type Unique_Id_Type is new Integer range 0 .. Max_Id_Type; Undefined_Id : constant Unique_Id_Type := 0; type Key_Count is new Integer range 0 .. Max_Key_Count; subtype Key_Index is Key_Count range 1 .. Key_Count'Last; type Key_Array is array (Key_Index range <>) of Unique_Id_Type with Predicate => Key_Array'First = 1; type Id_Manager_State (Capacity : Key_Count) is private; procedure Display_Objects (TheObject : Id_Manager_State); private type Id_Manager_State (Capacity : Key_Count) is record Id_Key : Key_Array (1 .. Capacity) := (others => Undefined_Id); Key_Size : Key_Count := 0; end record; end Id_Manager; ---- package body Id_Manager is procedure Display_Objects (TheObject : Id_Manager_State) is begin for Item of TheObject.Id_Key loop null; end loop; end Display_Objects; end Id_Manager; 2018-05-23 Ed Schonberg gcc/ada/ * sem_ch5.adb (Preanalyze_Range): The pre-analysis of the domain of iteration of an Ada2012 loop is performed to determine the type of the domain, but full analysis is performed once the loop is rewritten as a while-loop during expansion. The pre-analysis suppresses expansion; it must also suppress the generation of freeze nodes, which may otherwise appear in the wrong scope before rewritting. From-SVN: r260582 --- gcc/ada/ChangeLog | 9 +++++++++ gcc/ada/sem_ch5.adb | 11 +++++++++++ 2 files changed, 20 insertions(+) diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog index 31dca9e..b99ca1a 100644 --- a/gcc/ada/ChangeLog +++ b/gcc/ada/ChangeLog @@ -1,3 +1,12 @@ +2018-05-23 Ed Schonberg + + * sem_ch5.adb (Preanalyze_Range): The pre-analysis of the domain of + iteration of an Ada2012 loop is performed to determine the type of the + domain, but full analysis is performed once the loop is rewritten as a + while-loop during expansion. The pre-analysis suppresses expansion; it + must also suppress the generation of freeze nodes, which may otherwise + appear in the wrong scope before rewritting. + 2018-05-23 Hristian Kirtchev * sem_elab.adb: Update the section on suppressing elaboration warnings. diff --git a/gcc/ada/sem_ch5.adb b/gcc/ada/sem_ch5.adb index 2a3b1ff..2a1f222 100644 --- a/gcc/ada/sem_ch5.adb +++ b/gcc/ada/sem_ch5.adb @@ -4076,6 +4076,17 @@ package body Sem_Ch5 is Full_Analysis := False; Expander_Mode_Save_And_Set (False); + -- In addition to the above we must ecplicity suppress the + -- generation of freeze nodes which might otherwise be generated + -- during resolution of the range (e.g. if given by an attribute + -- that will freeze its prefix). + + Set_Must_Not_Freeze (R_Copy); + + if Nkind (R_Copy) = N_Attribute_Reference then + Set_Must_Not_Freeze (Prefix (R_Copy)); + end if; + Analyze (R_Copy); if Nkind (R_Copy) in N_Subexpr and then Is_Overloaded (R_Copy) then -- 2.7.4