From 51d4bdfb567c86de722ac5a72b79c8f51209228c Mon Sep 17 00:00:00 2001 From: Hristian Kirtchev Date: Tue, 31 Jul 2018 09:56:31 +0000 Subject: [PATCH] [Ada] Secondary stack leak with access-to-subprogram This patch modifies call resolution to recognize when the designated type of an access-to-subprogram requires secondary stack management, and establish the proper transient block. ------------ -- Source -- ------------ -- leak7.adb procedure Leak7 is Max_Iterations : constant := 10_000; function Func return String is begin return "Will this leak? Or will it dry?"; end Func; type Func_Ptr is access function return String; procedure Anonymous_Leak (Func : access function return String) is begin for Iteration in 1 .. Max_Iterations loop declare Val : constant String := Func.all; begin null; end; end loop; end Anonymous_Leak; procedure Named_Leak (Func : Func_Ptr) is begin for Iteration in 1 .. Max_Iterations loop declare Val : constant String := Func.all; begin null; end; end loop; end Named_Leak; begin Anonymous_Leak (Func'Access); Named_Leak (Func'Access); end Leak7; ---------------------------- -- Compilation and output -- ---------------------------- $ gnatmake -q leak7.adb $ valgrind ./leak7 >& leak7.txt $ grep -c "still reachable" leak7.txt 0 2018-07-31 Hristian Kirtchev gcc/ada/ * sem_res.adb (Resolve_Call): Establish a transient scope to manage the secondary stack when the designated type of an access-to-subprogram requires it. From-SVN: r263103 --- gcc/ada/ChangeLog | 6 ++++++ gcc/ada/sem_res.adb | 2 +- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog index 8207826..43d837b 100644 --- a/gcc/ada/ChangeLog +++ b/gcc/ada/ChangeLog @@ -1,3 +1,9 @@ +2018-07-31 Hristian Kirtchev + + * sem_res.adb (Resolve_Call): Establish a transient scope to + manage the secondary stack when the designated type of an + access-to-subprogram requires it. + 2018-07-31 Ed Schonberg * exp_ch7.adb (Check_Unnesting_Elaboration_Code): To find local diff --git a/gcc/ada/sem_res.adb b/gcc/ada/sem_res.adb index 5f9f1c3..ddfa543 100644 --- a/gcc/ada/sem_res.adb +++ b/gcc/ada/sem_res.adb @@ -6433,7 +6433,7 @@ package body Sem_Res is null; elsif Expander_Active - and then Ekind (Nam) = E_Function + and then Ekind_In (Nam, E_Function, E_Subprogram_Type) and then Requires_Transient_Scope (Etype (Nam)) then Establish_Transient_Scope (N, Manage_Sec_Stack => True); -- 2.7.4