------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- S Y S T E M . M E M O R Y --
-- --
-- B o d y --
-- --
-- Copyright (C) 2001-2023, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This version contains allocation tracking capability
-- The object file corresponding to this instrumented version is to be found
-- in libgmem.
-- When enabled, the subsystem logs all the calls to __gnat_malloc and
-- __gnat_free. This log can then be processed by gnatmem to detect
-- dynamic memory leaks.
-- To use this functionality, you must compile your application with -g
-- and then link with this object file:
-- gnatmake -g program -largs -lgmem
-- After compilation, you may use your program as usual except that upon
-- completion, it will generate in the current directory the file gmem.out.
-- You can then investigate for possible memory leaks and mismatch by calling
-- gnatmem with this file as an input:
-- gnatmem -i gmem.out program
-- See gnatmem section in the GNAT User's Guide for more details
-- NOTE: This capability is currently supported on the following targets:
-- Windows
-- AIX
-- GNU/Linux
-- HP-UX
-- Solaris
-- NOTE FOR FUTURE PLATFORMS SUPPORT: It is assumed that type Duration is
-- 64 bit. If the need arises to support architectures where this assumption
-- is incorrect, it will require changing the way timestamps of allocation
-- events are recorded.
pragma Source_File_Name (System.Memory, Body_File_Name => "memtrack.adb");
with Ada.Exceptions;
with GNAT.IO;
with System.Soft_Links;
with System.Traceback;
with System.Traceback_Entries;
with System.CRTL;
with System.OS_Lib;
with System.OS_Primitives;
package body System.Memory is
use Ada.Exceptions;
use System.Soft_Links;
use System.Traceback;
use System.Traceback_Entries;
use GNAT.IO;
function c_malloc (Size : size_t) return System.Address;
pragma Import (C, c_malloc, "malloc");
procedure c_free (Ptr : System.Address);
pragma Import (C, c_free, "free");
function c_realloc
(Ptr : System.Address; Size : size_t) return System.Address;
pragma Import (C, c_realloc, "realloc");
In_Child_After_Fork : Integer;
pragma Import (C, In_Child_After_Fork, "__gnat_in_child_after_fork");
subtype File_Ptr is CRTL.FILEs;
procedure Write (Ptr : System.Address; Size : size_t);
procedure Putc (Char : Character);
procedure Finalize;
pragma Export (C, Finalize, "__gnat_finalize");
-- Replace the default __gnat_finalize to properly close the log file
Address_Size : constant := System.Address'Max_Size_In_Storage_Elements;
-- Size in bytes of a pointer
Max_Call_Stack : constant := 200;
-- Maximum number of frames supported
Tracebk : Tracebacks_Array (1 .. Max_Call_Stack);
Num_Calls : aliased Integer := 0;
Gmemfname : constant String := "gmem.out" & ASCII.NUL;
-- Allocation log of a program is saved in a file gmem.out
-- ??? What about Ada.Command_Line.Command_Name & ".out" instead of static
-- gmem.out
Gmemfile : File_Ptr;
-- Global C file pointer to the allocation log
Needs_Init : Boolean := True;
-- Reset after first call to Gmem_Initialize
procedure Gmem_Initialize;
-- Initialization routine; opens the file and writes a header string. This
-- header string is used as a magic-tag to know if the .out file is to be
-- handled by GDB or by the GMEM (instrumented malloc/free) implementation.
First_Call : Boolean := True;
-- Depending on implementation, some of the traceback routines may
-- themselves do dynamic allocation. We use First_Call flag to avoid
-- infinite recursion
function Allow_Trace return Boolean;
pragma Inline (Allow_Trace);
-- Check if the memory trace is allowed
-----------------
-- Allow_Trace --
-----------------
function Allow_Trace return Boolean is
begin
if First_Call then
First_Call := False;
return In_Child_After_Fork = 0;
else
return False;
end if;
end Allow_Trace;
-----------
-- Alloc --
-----------
function Alloc (Size : size_t) return System.Address is
Result : aliased System.Address;
Actual_Size : aliased size_t := Size;
Timestamp : aliased Duration;
begin
if Size = size_t'Last then
Raise_Exception (Storage_Error'Identity, "object too large");
end if;
-- Change size from zero to non-zero. We still want a proper pointer
-- for the zero case because pointers to zero length objects have to
-- be distinct, but we can't just go ahead and allocate zero bytes,
-- since some malloc's return zero for a zero argument.
if Size = 0 then
Actual_Size := 1;
end if;
Lock_Task.all;
Result := c_malloc (Actual_Size);
if Allow_Trace then
-- Logs allocation call
-- format is:
-- 'A' <mem addr> <size chunk> <len backtrace> <addr1> ... <addrn>
if Needs_Init then
Gmem_Initialize;
end if;
Timestamp := System.OS_Primitives.Clock;
Call_Chain
(Tracebk, Max_Call_Stack, Num_Calls, Skip_Frames => 2);
Putc ('A');
Write (Result'Address, Address_Size);
Write (Actual_Size'Address, size_t'Max_Size_In_Storage_Elements);
Write (Timestamp'Address, Duration'Max_Size_In_Storage_Elements);
Write (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements);
for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
declare
Ptr : System.Address := PC_For (Tracebk (J));
begin
Write (Ptr'Address, Address_Size);
end;
end loop;
First_Call := True;
end if;
Unlock_Task.all;
if Result = System.Null_Address then
Raise_Exception (Storage_Error'Identity, "heap exhausted");
end if;
return Result;
end Alloc;
--------------
-- Finalize --
--------------
procedure Finalize is
begin
if not Needs_Init and then CRTL.fclose (Gmemfile) /= 0 then
Put_Line ("gmem close error: " & OS_Lib.Errno_Message);
end if;
end Finalize;
----------
-- Free --
----------
procedure Free (Ptr : System.Address) is
Addr : aliased constant System.Address := Ptr;
Timestamp : aliased Duration;
begin
Lock_Task.all;
if Allow_Trace then
-- Logs deallocation call
-- format is:
-- 'D' <mem addr> <len backtrace> <addr1> ... <addrn>
if Needs_Init then
Gmem_Initialize;
end if;
Call_Chain
(Tracebk, Max_Call_Stack, Num_Calls, Skip_Frames => 2);
Timestamp := System.OS_Primitives.Clock;
Putc ('D');
Write (Addr'Address, Address_Size);
Write (Timestamp'Address, Duration'Max_Size_In_Storage_Elements);
Write (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements);
for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
declare
Ptr : System.Address := PC_For (Tracebk (J));
begin
Write (Ptr'Address, Address_Size);
end;
end loop;
c_free (Ptr);
First_Call := True;
end if;
Unlock_Task.all;
end Free;
---------------------
-- Gmem_Initialize --
---------------------
procedure Gmem_Initialize is
Timestamp : aliased Duration;
File_Mode : constant String := "wb" & ASCII.NUL;
begin
if Needs_Init then
Needs_Init := False;
System.OS_Primitives.Initialize;
Timestamp := System.OS_Primitives.Clock;
Gmemfile := CRTL.fopen (Gmemfname'Address, File_Mode'Address);
if Gmemfile = System.Null_Address then
Put_Line ("Couldn't open gnatmem log file for writing");
OS_Lib.OS_Exit (255);
end if;
declare
S : constant String := "GMEM DUMP" & ASCII.LF;
begin
Write (S'Address, S'Length);
Write (Timestamp'Address, Duration'Max_Size_In_Storage_Elements);
end;
end if;
end Gmem_Initialize;
----------
-- Putc --
----------
procedure Putc (Char : Character) is
C : constant Integer := Character'Pos (Char);
begin
if CRTL.fputc (C, Gmemfile) /= C then
Put_Line ("gmem fputc error: " & OS_Lib.Errno_Message);
end if;
end Putc;
-------------
-- Realloc --
-------------
function Realloc
(Ptr : System.Address;
Size : size_t) return System.Address
is
Addr : aliased constant System.Address := Ptr;
Result : aliased System.Address;
Timestamp : aliased Duration;
begin
-- For the purposes of allocations logging, we treat realloc as a free
-- followed by malloc. This is not exactly accurate, but is a good way
-- to fit it into malloc/free-centered reports.
if Size = size_t'Last then
Raise_Exception (Storage_Error'Identity, "object too large");
end if;
Abort_Defer.all;
Lock_Task.all;
if Allow_Trace then
-- We first log deallocation call
if Needs_Init then
Gmem_Initialize;
end if;
Call_Chain
(Tracebk, Max_Call_Stack, Num_Calls, Skip_Frames => 2);
Timestamp := System.OS_Primitives.Clock;
Putc ('D');
Write (Addr'Address, Address_Size);
Write (Timestamp'Address, Duration'Max_Size_In_Storage_Elements);
Write (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements);
for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
declare
Ptr : System.Address := PC_For (Tracebk (J));
begin
Write (Ptr'Address, Address_Size);
end;
end loop;
-- Now perform actual realloc
Result := c_realloc (Ptr, Size);
-- Log allocation call using the same backtrace
Putc ('A');
Write (Result'Address, Address_Size);
Write (Size'Address, size_t'Max_Size_In_Storage_Elements);
Write (Timestamp'Address, Duration'Max_Size_In_Storage_Elements);
Write (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements);
for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
declare
Ptr : System.Address := PC_For (Tracebk (J));
begin
Write (Ptr'Address, Address_Size);
end;
end loop;
First_Call := True;
end if;
Unlock_Task.all;
Abort_Undefer.all;
if Result = System.Null_Address then
Raise_Exception (Storage_Error'Identity, "heap exhausted");
end if;
return Result;
end Realloc;
-----------
-- Write --
-----------
procedure Write (Ptr : System.Address; Size : size_t) is
function fwrite
(buffer : System.Address;
size : size_t;
count : size_t;
stream : File_Ptr) return size_t;
pragma Import (C, fwrite);
begin
if fwrite (Ptr, Size, 1, Gmemfile) /= 1 then
Put_Line ("gmem fwrite error: " & OS_Lib.Errno_Message);
end if;
end Write;
end System.Memory;