------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- G N A T . D E B U G _ P O O L S --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2012, 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 --
-- . --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Ada.Exceptions.Traceback;
with GNAT.IO; use GNAT.IO;
with System.Address_Image;
with System.Memory; use System.Memory;
with System.Soft_Links; use System.Soft_Links;
with System.Traceback_Entries; use System.Traceback_Entries;
with GNAT.HTable;
with GNAT.Traceback; use GNAT.Traceback;
with Ada.Unchecked_Conversion;
package body GNAT.Debug_Pools is
Default_Alignment : constant := Standard'Maximum_Alignment;
-- Alignment used for the memory chunks returned by Allocate. Using this
-- value guarantees that this alignment will be compatible with all types
-- and at the same time makes it easy to find the location of the extra
-- header allocated for each chunk.
Max_Ignored_Levels : constant Natural := 10;
-- Maximum number of levels that will be ignored in backtraces. This is so
-- that we still have enough significant levels in the tracebacks returned
-- to the user.
--
-- The value 10 is chosen as being greater than the maximum callgraph
-- in this package. Its actual value is not really relevant, as long as it
-- is high enough to make sure we still have enough frames to return to
-- the user after we have hidden the frames internal to this package.
---------------------------
-- Back Trace Hash Table --
---------------------------
-- This package needs to store one set of tracebacks for each allocation
-- point (when was it allocated or deallocated). This would use too much
-- memory, so the tracebacks are actually stored in a hash table, and
-- we reference elements in this hash table instead.
-- This hash-table will remain empty if the discriminant Stack_Trace_Depth
-- for the pools is set to 0.
-- This table is a global table, that can be shared among all debug pools
-- with no problems.
type Header is range 1 .. 1023;
-- Number of elements in the hash-table
type Tracebacks_Array_Access
is access GNAT.Traceback.Tracebacks_Array;
type Traceback_Kind is (Alloc, Dealloc, Indirect_Alloc, Indirect_Dealloc);
type Traceback_Htable_Elem;
type Traceback_Htable_Elem_Ptr
is access Traceback_Htable_Elem;
type Traceback_Htable_Elem is record
Traceback : Tracebacks_Array_Access;
Kind : Traceback_Kind;
Count : Natural;
Total : Byte_Count;
Next : Traceback_Htable_Elem_Ptr;
end record;
-- Subprograms used for the Backtrace_Htable instantiation
procedure Set_Next
(E : Traceback_Htable_Elem_Ptr;
Next : Traceback_Htable_Elem_Ptr);
pragma Inline (Set_Next);
function Next
(E : Traceback_Htable_Elem_Ptr) return Traceback_Htable_Elem_Ptr;
pragma Inline (Next);
function Get_Key
(E : Traceback_Htable_Elem_Ptr) return Tracebacks_Array_Access;
pragma Inline (Get_Key);
function Hash (T : Tracebacks_Array_Access) return Header;
pragma Inline (Hash);
function Equal (K1, K2 : Tracebacks_Array_Access) return Boolean;
-- Why is this not inlined???
-- The hash table for back traces
package Backtrace_Htable is new GNAT.HTable.Static_HTable
(Header_Num => Header,
Element => Traceback_Htable_Elem,
Elmt_Ptr => Traceback_Htable_Elem_Ptr,
Null_Ptr => null,
Set_Next => Set_Next,
Next => Next,
Key => Tracebacks_Array_Access,
Get_Key => Get_Key,
Hash => Hash,
Equal => Equal);
-----------------------
-- Allocations table --
-----------------------
type Allocation_Header;
type Allocation_Header_Access is access Allocation_Header;
type Traceback_Ptr_Or_Address is new System.Address;
-- A type that acts as a C union, and is either a System.Address or a
-- Traceback_Htable_Elem_Ptr.
-- The following record stores extra information that needs to be
-- memorized for each block allocated with the special debug pool.
type Allocation_Header is record
Allocation_Address : System.Address;
-- Address of the block returned by malloc, possibly unaligned
Block_Size : Storage_Offset;
-- Needed only for advanced freeing algorithms (traverse all allocated
-- blocks for potential references). This value is negated when the
-- chunk of memory has been logically freed by the application. This
-- chunk has not been physically released yet.
Alloc_Traceback : Traceback_Htable_Elem_Ptr;
-- ??? comment required
Dealloc_Traceback : Traceback_Ptr_Or_Address;
-- Pointer to the traceback for the allocation (if the memory chunk is
-- still valid), or to the first deallocation otherwise. Make sure this
-- is a thin pointer to save space.
--
-- Dealloc_Traceback is also for blocks that are still allocated to
-- point to the previous block in the list. This saves space in this
-- header, and make manipulation of the lists of allocated pointers
-- faster.
Next : System.Address;
-- Point to the next block of the same type (either allocated or
-- logically freed) in memory. This points to the beginning of the user
-- data, and does not include the header of that block.
end record;
function Header_Of (Address : System.Address)
return Allocation_Header_Access;
pragma Inline (Header_Of);
-- Return the header corresponding to a previously allocated address
function To_Address is new Ada.Unchecked_Conversion
(Traceback_Ptr_Or_Address, System.Address);
function To_Address is new Ada.Unchecked_Conversion
(System.Address, Traceback_Ptr_Or_Address);
function To_Traceback is new Ada.Unchecked_Conversion
(Traceback_Ptr_Or_Address, Traceback_Htable_Elem_Ptr);
function To_Traceback is new Ada.Unchecked_Conversion
(Traceback_Htable_Elem_Ptr, Traceback_Ptr_Or_Address);
Header_Offset : constant Storage_Count :=
Default_Alignment *
((Allocation_Header'Size / System.Storage_Unit
+ Default_Alignment - 1) / Default_Alignment);
-- Offset of user data after allocation header
Minimum_Allocation : constant Storage_Count :=
Default_Alignment - 1 + Header_Offset;
-- Minimal allocation: size of allocation_header rounded up to next
-- multiple of default alignment + worst-case padding.
-----------------------
-- Local subprograms --
-----------------------
function Find_Or_Create_Traceback
(Pool : Debug_Pool;
Kind : Traceback_Kind;
Size : Storage_Count;
Ignored_Frame_Start : System.Address;
Ignored_Frame_End : System.Address) return Traceback_Htable_Elem_Ptr;
-- Return an element matching the current traceback (omitting the frames
-- that are in the current package). If this traceback already existed in
-- the htable, a pointer to this is returned to spare memory. Null is
-- returned if the pool is set not to store tracebacks. If the traceback
-- already existed in the table, the count is incremented so that
-- Dump_Tracebacks returns useful results. All addresses up to, and
-- including, an address between Ignored_Frame_Start .. Ignored_Frame_End
-- are ignored.
function Output_File (Pool : Debug_Pool) return File_Type;
pragma Inline (Output_File);
-- Returns file_type on which error messages have to be generated for Pool
procedure Put_Line
(File : File_Type;
Depth : Natural;
Traceback : Tracebacks_Array_Access;
Ignored_Frame_Start : System.Address := System.Null_Address;
Ignored_Frame_End : System.Address := System.Null_Address);
-- Print Traceback to File. If Traceback is null, print the call_chain
-- at the current location, up to Depth levels, ignoring all addresses
-- up to the first one in the range:
-- Ignored_Frame_Start .. Ignored_Frame_End
package Validity is
function Is_Valid (Storage : System.Address) return Boolean;
pragma Inline (Is_Valid);
-- Return True if Storage is the address of a block that the debug pool
-- has under its control, in which case Header_Of may be used to access
-- the associated allocation header.
procedure Set_Valid (Storage : System.Address; Value : Boolean);
pragma Inline (Set_Valid);
-- Mark the address Storage as being under control of the memory pool
-- (if Value is True), or not (if Value is False).
end Validity;
use Validity;
procedure Set_Dead_Beef
(Storage_Address : System.Address;
Size_In_Storage_Elements : Storage_Count);
-- Set the contents of the memory block pointed to by Storage_Address to
-- the 16#DEADBEEF# pattern. If Size_In_Storage_Elements is not a multiple
-- of the length of this pattern, the last instance may be partial.
procedure Free_Physically (Pool : in out Debug_Pool);
-- Start to physically release some memory to the system, until the amount
-- of logically (but not physically) freed memory is lower than the
-- expected amount in Pool.
procedure Allocate_End;
procedure Deallocate_End;
procedure Dereference_End;
-- These procedures are used as markers when computing the stacktraces,
-- so that addresses in the debug pool itself are not reported to the user.
Code_Address_For_Allocate_End : System.Address;
Code_Address_For_Deallocate_End : System.Address;
Code_Address_For_Dereference_End : System.Address;
-- Taking the address of the above procedures will not work on some
-- architectures (HPUX and VMS for instance). Thus we do the same thing
-- that is done in a-except.adb, and get the address of labels instead
procedure Skip_Levels
(Depth : Natural;
Trace : Tracebacks_Array;
Start : out Natural;
Len : in out Natural;
Ignored_Frame_Start : System.Address;
Ignored_Frame_End : System.Address);
-- Set Start .. Len to the range of values from Trace that should be output
-- to the user. This range of values excludes any address prior to the
-- first one in Ignored_Frame_Start .. Ignored_Frame_End (basically
-- addresses internal to this package). Depth is the number of levels that
-- the user is interested in.
---------------
-- Header_Of --
---------------
function Header_Of (Address : System.Address)
return Allocation_Header_Access
is
function Convert is new Ada.Unchecked_Conversion
(System.Address, Allocation_Header_Access);
begin
return Convert (Address - Header_Offset);
end Header_Of;
--------------
-- Set_Next --
--------------
procedure Set_Next
(E : Traceback_Htable_Elem_Ptr;
Next : Traceback_Htable_Elem_Ptr)
is
begin
E.Next := Next;
end Set_Next;
----------
-- Next --
----------
function Next
(E : Traceback_Htable_Elem_Ptr) return Traceback_Htable_Elem_Ptr is
begin
return E.Next;
end Next;
-----------
-- Equal --
-----------
function Equal (K1, K2 : Tracebacks_Array_Access) return Boolean is
use Ada.Exceptions.Traceback;
begin
return K1.all = K2.all;
end Equal;
-------------
-- Get_Key --
-------------
function Get_Key
(E : Traceback_Htable_Elem_Ptr) return Tracebacks_Array_Access
is
begin
return E.Traceback;
end Get_Key;
----------
-- Hash --
----------
function Hash (T : Tracebacks_Array_Access) return Header is
Result : Integer_Address := 0;
begin
for X in T'Range loop
Result := Result + To_Integer (PC_For (T (X)));
end loop;
return Header (1 + Result mod Integer_Address (Header'Last));
end Hash;
-----------------
-- Output_File --
-----------------
function Output_File (Pool : Debug_Pool) return File_Type is
begin
if Pool.Errors_To_Stdout then
return Standard_Output;
else
return Standard_Error;
end if;
end Output_File;
--------------
-- Put_Line --
--------------
procedure Put_Line
(File : File_Type;
Depth : Natural;
Traceback : Tracebacks_Array_Access;
Ignored_Frame_Start : System.Address := System.Null_Address;
Ignored_Frame_End : System.Address := System.Null_Address)
is
procedure Print (Tr : Tracebacks_Array);
-- Print the traceback to standard_output
-----------
-- Print --
-----------
procedure Print (Tr : Tracebacks_Array) is
begin
for J in Tr'Range loop
Put (File, "0x" & Address_Image (PC_For (Tr (J))) & ' ');
end loop;
Put (File, ASCII.LF);
end Print;
-- Start of processing for Put_Line
begin
if Traceback = null then
declare
Tr : aliased Tracebacks_Array (1 .. Depth + Max_Ignored_Levels);
Start, Len : Natural;
begin
Call_Chain (Tr, Len);
Skip_Levels (Depth, Tr, Start, Len,
Ignored_Frame_Start, Ignored_Frame_End);
Print (Tr (Start .. Len));
end;
else
Print (Traceback.all);
end if;
end Put_Line;
-----------------
-- Skip_Levels --
-----------------
procedure Skip_Levels
(Depth : Natural;
Trace : Tracebacks_Array;
Start : out Natural;
Len : in out Natural;
Ignored_Frame_Start : System.Address;
Ignored_Frame_End : System.Address)
is
begin
Start := Trace'First;
while Start <= Len
and then (PC_For (Trace (Start)) < Ignored_Frame_Start
or else PC_For (Trace (Start)) > Ignored_Frame_End)
loop
Start := Start + 1;
end loop;
Start := Start + 1;
-- Just in case: make sure we have a traceback even if Ignore_Till
-- wasn't found.
if Start > Len then
Start := 1;
end if;
if Len - Start + 1 > Depth then
Len := Depth + Start - 1;
end if;
end Skip_Levels;
------------------------------
-- Find_Or_Create_Traceback --
------------------------------
function Find_Or_Create_Traceback
(Pool : Debug_Pool;
Kind : Traceback_Kind;
Size : Storage_Count;
Ignored_Frame_Start : System.Address;
Ignored_Frame_End : System.Address) return Traceback_Htable_Elem_Ptr
is
begin
if Pool.Stack_Trace_Depth = 0 then
return null;
end if;
declare
Trace : aliased Tracebacks_Array
(1 .. Integer (Pool.Stack_Trace_Depth) + Max_Ignored_Levels);
Len, Start : Natural;
Elem : Traceback_Htable_Elem_Ptr;
begin
Call_Chain (Trace, Len);
Skip_Levels (Pool.Stack_Trace_Depth, Trace, Start, Len,
Ignored_Frame_Start, Ignored_Frame_End);
-- Check if the traceback is already in the table
Elem :=
Backtrace_Htable.Get (Trace (Start .. Len)'Unrestricted_Access);
-- If not, insert it
if Elem = null then
Elem := new Traceback_Htable_Elem'
(Traceback => new Tracebacks_Array'(Trace (Start .. Len)),
Count => 1,
Kind => Kind,
Total => Byte_Count (Size),
Next => null);
Backtrace_Htable.Set (Elem);
else
Elem.Count := Elem.Count + 1;
Elem.Total := Elem.Total + Byte_Count (Size);
end if;
return Elem;
end;
end Find_Or_Create_Traceback;
--------------
-- Validity --
--------------
package body Validity is
-- The validity bits of the allocated blocks are kept in a has table.
-- Each component of the hash table contains the validity bits for a
-- 16 Mbyte memory chunk.
-- The reason the validity bits are kept for chunks of memory rather
-- than in a big array is that on some 64 bit platforms, it may happen
-- that two chunk of allocated data are very far from each other.
Memory_Chunk_Size : constant Integer_Address := 2 ** 24; -- 16 MB
Validity_Divisor : constant := Default_Alignment * System.Storage_Unit;
Max_Validity_Byte_Index : constant :=
Memory_Chunk_Size / Validity_Divisor;
subtype Validity_Byte_Index is Integer_Address
range 0 .. Max_Validity_Byte_Index - 1;
type Byte is mod 2 ** System.Storage_Unit;
type Validity_Bits is array (Validity_Byte_Index) of Byte;
type Validity_Bits_Ref is access all Validity_Bits;
No_Validity_Bits : constant Validity_Bits_Ref := null;
Max_Header_Num : constant := 1023;
type Header_Num is range 0 .. Max_Header_Num - 1;
function Hash (F : Integer_Address) return Header_Num;
package Validy_Htable is new GNAT.HTable.Simple_HTable
(Header_Num => Header_Num,
Element => Validity_Bits_Ref,
No_Element => No_Validity_Bits,
Key => Integer_Address,
Hash => Hash,
Equal => "=");
-- Table to keep the validity bit blocks for the allocated data
function To_Pointer is new Ada.Unchecked_Conversion
(System.Address, Validity_Bits_Ref);
procedure Memset (A : Address; C : Integer; N : size_t);
pragma Import (C, Memset, "memset");
----------
-- Hash --
----------
function Hash (F : Integer_Address) return Header_Num is
begin
return Header_Num (F mod Max_Header_Num);
end Hash;
--------------
-- Is_Valid --
--------------
function Is_Valid (Storage : System.Address) return Boolean is
Int_Storage : constant Integer_Address := To_Integer (Storage);
begin
-- The pool only returns addresses aligned on Default_Alignment so
-- anything off cannot be a valid block address and we can return
-- early in this case. We actually have to since our data structures
-- map validity bits for such aligned addresses only.
if Int_Storage mod Default_Alignment /= 0 then
return False;
end if;
declare
Block_Number : constant Integer_Address :=
Int_Storage / Memory_Chunk_Size;
Ptr : constant Validity_Bits_Ref :=
Validy_Htable.Get (Block_Number);
Offset : constant Integer_Address :=
(Int_Storage -
(Block_Number * Memory_Chunk_Size)) /
Default_Alignment;
Bit : constant Byte :=
2 ** Natural (Offset mod System.Storage_Unit);
begin
if Ptr = No_Validity_Bits then
return False;
else
return (Ptr (Offset / System.Storage_Unit) and Bit) /= 0;
end if;
end;
end Is_Valid;
---------------
-- Set_Valid --
---------------
procedure Set_Valid (Storage : System.Address; Value : Boolean) is
Int_Storage : constant Integer_Address := To_Integer (Storage);
Block_Number : constant Integer_Address :=
Int_Storage / Memory_Chunk_Size;
Ptr : Validity_Bits_Ref := Validy_Htable.Get (Block_Number);
Offset : constant Integer_Address :=
(Int_Storage - (Block_Number * Memory_Chunk_Size)) /
Default_Alignment;
Bit : constant Byte :=
2 ** Natural (Offset mod System.Storage_Unit);
begin
if Ptr = No_Validity_Bits then
-- First time in this memory area: allocate a new block and put
-- it in the table.
if Value then
Ptr := To_Pointer (Alloc (size_t (Max_Validity_Byte_Index)));
Validy_Htable.Set (Block_Number, Ptr);
Memset (Ptr.all'Address, 0, size_t (Max_Validity_Byte_Index));
Ptr (Offset / System.Storage_Unit) := Bit;
end if;
else
if Value then
Ptr (Offset / System.Storage_Unit) :=
Ptr (Offset / System.Storage_Unit) or Bit;
else
Ptr (Offset / System.Storage_Unit) :=
Ptr (Offset / System.Storage_Unit) and (not Bit);
end if;
end if;
end Set_Valid;
end Validity;
--------------
-- Allocate --
--------------
procedure Allocate
(Pool : in out Debug_Pool;
Storage_Address : out Address;
Size_In_Storage_Elements : Storage_Count;
Alignment : Storage_Count)
is
pragma Unreferenced (Alignment);
-- Ignored, we always force 'Default_Alignment
type Local_Storage_Array is new Storage_Array
(1 .. Size_In_Storage_Elements + Minimum_Allocation);
type Ptr is access Local_Storage_Array;
-- On some systems, we might want to physically protect pages against
-- writing when they have been freed (of course, this is expensive in
-- terms of wasted memory). To do that, all we should have to do it to
-- set the size of this array to the page size. See mprotect().
Current : Byte_Count;
P : Ptr;
Trace : Traceback_Htable_Elem_Ptr;
begin
<>
Lock_Task.all;
-- If necessary, start physically releasing memory. The reason this is
-- done here, although Pool.Logically_Deallocated has not changed above,
-- is so that we do this only after a series of deallocations (e.g loop
-- that deallocates a big array). If we were doing that in Deallocate,
-- we might be physically freeing memory several times during the loop,
-- which is expensive.
if Pool.Logically_Deallocated >
Byte_Count (Pool.Maximum_Logically_Freed_Memory)
then
Free_Physically (Pool);
end if;
-- Use standard (i.e. through malloc) allocations. This automatically
-- raises Storage_Error if needed. We also try once more to physically
-- release memory, so that even marked blocks, in the advanced scanning,
-- are freed. Note that we do not initialize the storage array since it
-- is not necessary to do so (however this will cause bogus valgrind
-- warnings, which should simply be ignored).
begin
P := new Local_Storage_Array;
exception
when Storage_Error =>
Free_Physically (Pool);
P := new Local_Storage_Array;
end;
Storage_Address :=
To_Address
(Default_Alignment *
((To_Integer (P.all'Address) + Default_Alignment - 1)
/ Default_Alignment)
+ Integer_Address (Header_Offset));
-- Computation is done in Integer_Address, not Storage_Offset, because
-- the range of Storage_Offset may not be large enough.
pragma Assert ((Storage_Address - System.Null_Address)
mod Default_Alignment = 0);
pragma Assert (Storage_Address + Size_In_Storage_Elements
<= P.all'Address + P'Length);
Trace := Find_Or_Create_Traceback
(Pool, Alloc, Size_In_Storage_Elements,
Allocate_Label'Address, Code_Address_For_Allocate_End);
pragma Warnings (Off);
-- Turn warning on alignment for convert call off. We know that in fact
-- this conversion is safe since P itself is always aligned on
-- Default_Alignment.
Header_Of (Storage_Address).all :=
(Allocation_Address => P.all'Address,
Alloc_Traceback => Trace,
Dealloc_Traceback => To_Traceback (null),
Next => Pool.First_Used_Block,
Block_Size => Size_In_Storage_Elements);
pragma Warnings (On);
-- Link this block in the list of used blocks. This will be used to list
-- memory leaks in Print_Info, and for the advanced schemes of
-- Physical_Free, where we want to traverse all allocated blocks and
-- search for possible references.
-- We insert in front, since most likely we'll be freeing the most
-- recently allocated blocks first (the older one might stay allocated
-- for the whole life of the application).
if Pool.First_Used_Block /= System.Null_Address then
Header_Of (Pool.First_Used_Block).Dealloc_Traceback :=
To_Address (Storage_Address);
end if;
Pool.First_Used_Block := Storage_Address;
-- Mark the new address as valid
Set_Valid (Storage_Address, True);
if Pool.Low_Level_Traces then
Put (Output_File (Pool),
"info: Allocated"
& Storage_Count'Image (Size_In_Storage_Elements)
& " bytes at 0x" & Address_Image (Storage_Address)
& " (physically:"
& Storage_Count'Image (Local_Storage_Array'Length)
& " bytes at 0x" & Address_Image (P.all'Address)
& "), at ");
Put_Line (Output_File (Pool), Pool.Stack_Trace_Depth, null,
Allocate_Label'Address,
Code_Address_For_Deallocate_End);
end if;
-- Update internal data
Pool.Allocated :=
Pool.Allocated + Byte_Count (Size_In_Storage_Elements);
Current := Pool.Allocated -
Pool.Logically_Deallocated -
Pool.Physically_Deallocated;
if Current > Pool.High_Water then
Pool.High_Water := Current;
end if;
Unlock_Task.all;
exception
when others =>
Unlock_Task.all;
raise;
end Allocate;
------------------
-- Allocate_End --
------------------
-- DO NOT MOVE, this must be right after Allocate. This is similar to what
-- is done in a-except, so that we can hide the traceback frames internal
-- to this package
procedure Allocate_End is
begin
<>
Code_Address_For_Allocate_End := Allocate_End_Label'Address;
end Allocate_End;
-------------------
-- Set_Dead_Beef --
-------------------
procedure Set_Dead_Beef
(Storage_Address : System.Address;
Size_In_Storage_Elements : Storage_Count)
is
Dead_Bytes : constant := 4;
type Data is mod 2 ** (Dead_Bytes * 8);
for Data'Size use Dead_Bytes * 8;
Dead : constant Data := 16#DEAD_BEEF#;
type Dead_Memory is array
(1 .. Size_In_Storage_Elements / Dead_Bytes) of Data;
type Mem_Ptr is access Dead_Memory;
type Byte is mod 2 ** 8;
for Byte'Size use 8;
type Dead_Memory_Bytes is array (0 .. 2) of Byte;
type Dead_Memory_Bytes_Ptr is access Dead_Memory_Bytes;
function From_Ptr is new Ada.Unchecked_Conversion
(System.Address, Mem_Ptr);
function From_Ptr is new Ada.Unchecked_Conversion
(System.Address, Dead_Memory_Bytes_Ptr);
M : constant Mem_Ptr := From_Ptr (Storage_Address);
M2 : Dead_Memory_Bytes_Ptr;
Modulo : constant Storage_Count :=
Size_In_Storage_Elements mod Dead_Bytes;
begin
M.all := (others => Dead);
-- Any bytes left (up to three of them)
if Modulo /= 0 then
M2 := From_Ptr (Storage_Address + M'Length * Dead_Bytes);
M2 (0) := 16#DE#;
if Modulo >= 2 then
M2 (1) := 16#AD#;
if Modulo >= 3 then
M2 (2) := 16#BE#;
end if;
end if;
end if;
end Set_Dead_Beef;
---------------------
-- Free_Physically --
---------------------
procedure Free_Physically (Pool : in out Debug_Pool) is
type Byte is mod 256;
type Byte_Access is access Byte;
function To_Byte is new Ada.Unchecked_Conversion
(System.Address, Byte_Access);
type Address_Access is access System.Address;
function To_Address_Access is new Ada.Unchecked_Conversion
(System.Address, Address_Access);
In_Use_Mark : constant Byte := 16#D#;
Free_Mark : constant Byte := 16#F#;
Total_Freed : Storage_Count := 0;
procedure Reset_Marks;
-- Unmark all the logically freed blocks, so that they are considered
-- for physical deallocation
procedure Mark
(H : Allocation_Header_Access; A : System.Address; In_Use : Boolean);
-- Mark the user data block starting at A. For a block of size zero,
-- nothing is done. For a block with a different size, the first byte
-- is set to either "D" (in use) or "F" (free).
function Marked (A : System.Address) return Boolean;
-- Return true if the user data block starting at A might be in use
-- somewhere else
procedure Mark_Blocks;
-- Traverse all allocated blocks, and search for possible references
-- to logically freed blocks. Mark them appropriately
procedure Free_Blocks (Ignore_Marks : Boolean);
-- Physically release blocks. Only the blocks that haven't been marked
-- will be released, unless Ignore_Marks is true.
-----------------
-- Free_Blocks --
-----------------
procedure Free_Blocks (Ignore_Marks : Boolean) is
Header : Allocation_Header_Access;
Tmp : System.Address := Pool.First_Free_Block;
Next : System.Address;
Previous : System.Address := System.Null_Address;
begin
while Tmp /= System.Null_Address
and then Total_Freed < Pool.Minimum_To_Free
loop
Header := Header_Of (Tmp);
-- If we know, or at least assume, the block is no longer
-- referenced anywhere, we can free it physically.
if Ignore_Marks or else not Marked (Tmp) then
declare
pragma Suppress (All_Checks);
-- Suppress the checks on this section. If they are overflow
-- errors, it isn't critical, and we'd rather avoid a
-- Constraint_Error in that case.
begin
-- Note that block_size < zero for freed blocks
Pool.Physically_Deallocated :=
Pool.Physically_Deallocated -
Byte_Count (Header.Block_Size);
Pool.Logically_Deallocated :=
Pool.Logically_Deallocated +
Byte_Count (Header.Block_Size);
Total_Freed := Total_Freed - Header.Block_Size;
end;
Next := Header.Next;
if Pool.Low_Level_Traces then
Put_Line
(Output_File (Pool),
"info: Freeing physical memory "
& Storage_Count'Image
((abs Header.Block_Size) + Minimum_Allocation)
& " bytes at 0x"
& Address_Image (Header.Allocation_Address));
end if;
System.Memory.Free (Header.Allocation_Address);
Set_Valid (Tmp, False);
-- Remove this block from the list
if Previous = System.Null_Address then
Pool.First_Free_Block := Next;
else
Header_Of (Previous).Next := Next;
end if;
Tmp := Next;
else
Previous := Tmp;
Tmp := Header.Next;
end if;
end loop;
end Free_Blocks;
----------
-- Mark --
----------
procedure Mark
(H : Allocation_Header_Access;
A : System.Address;
In_Use : Boolean)
is
begin
if H.Block_Size /= 0 then
To_Byte (A).all := (if In_Use then In_Use_Mark else Free_Mark);
end if;
end Mark;
-----------------
-- Mark_Blocks --
-----------------
procedure Mark_Blocks is
Tmp : System.Address := Pool.First_Used_Block;
Previous : System.Address;
Last : System.Address;
Pointed : System.Address;
Header : Allocation_Header_Access;
begin
-- For each allocated block, check its contents. Things that look
-- like a possible address are used to mark the blocks so that we try
-- and keep them, for better detection in case of invalid access.
-- This mechanism is far from being fool-proof: it doesn't check the
-- stacks of the threads, doesn't check possible memory allocated not
-- under control of this debug pool. But it should allow us to catch
-- more cases.
while Tmp /= System.Null_Address loop
Previous := Tmp;
Last := Tmp + Header_Of (Tmp).Block_Size;
while Previous < Last loop
-- ??? Should we move byte-per-byte, or consider that addresses
-- are always aligned on 4-bytes boundaries ? Let's use the
-- fastest for now.
Pointed := To_Address_Access (Previous).all;
if Is_Valid (Pointed) then
Header := Header_Of (Pointed);
-- Do not even attempt to mark blocks in use. That would
-- screw up the whole application, of course.
if Header.Block_Size < 0 then
Mark (Header, Pointed, In_Use => True);
end if;
end if;
Previous := Previous + System.Address'Size;
end loop;
Tmp := Header_Of (Tmp).Next;
end loop;
end Mark_Blocks;
------------
-- Marked --
------------
function Marked (A : System.Address) return Boolean is
begin
return To_Byte (A).all = In_Use_Mark;
end Marked;
-----------------
-- Reset_Marks --
-----------------
procedure Reset_Marks is
Current : System.Address := Pool.First_Free_Block;
Header : Allocation_Header_Access;
begin
while Current /= System.Null_Address loop
Header := Header_Of (Current);
Mark (Header, Current, False);
Current := Header.Next;
end loop;
end Reset_Marks;
-- Start of processing for Free_Physically
begin
Lock_Task.all;
if Pool.Advanced_Scanning then
-- Reset the mark for each freed block
Reset_Marks;
Mark_Blocks;
end if;
Free_Blocks (Ignore_Marks => not Pool.Advanced_Scanning);
-- The contract is that we need to free at least Minimum_To_Free bytes,
-- even if this means freeing marked blocks in the advanced scheme
if Total_Freed < Pool.Minimum_To_Free
and then Pool.Advanced_Scanning
then
Pool.Marked_Blocks_Deallocated := True;
Free_Blocks (Ignore_Marks => True);
end if;
Unlock_Task.all;
exception
when others =>
Unlock_Task.all;
raise;
end Free_Physically;
----------------
-- Deallocate --
----------------
procedure Deallocate
(Pool : in out Debug_Pool;
Storage_Address : Address;
Size_In_Storage_Elements : Storage_Count;
Alignment : Storage_Count)
is
pragma Unreferenced (Alignment);
Header : constant Allocation_Header_Access :=
Header_Of (Storage_Address);
Valid : Boolean;
Previous : System.Address;
begin
<>
Lock_Task.all;
Valid := Is_Valid (Storage_Address);
if not Valid then
Unlock_Task.all;
if Pool.Raise_Exceptions then
raise Freeing_Not_Allocated_Storage;
else
Put (Output_File (Pool),
"error: Freeing not allocated storage, at ");
Put_Line (Output_File (Pool), Pool.Stack_Trace_Depth, null,
Deallocate_Label'Address,
Code_Address_For_Deallocate_End);
end if;
elsif Header.Block_Size < 0 then
Unlock_Task.all;
if Pool.Raise_Exceptions then
raise Freeing_Deallocated_Storage;
else
Put (Output_File (Pool),
"error: Freeing already deallocated storage, at ");
Put_Line (Output_File (Pool), Pool.Stack_Trace_Depth, null,
Deallocate_Label'Address,
Code_Address_For_Deallocate_End);
Put (Output_File (Pool), " Memory already deallocated at ");
Put_Line
(Output_File (Pool), 0,
To_Traceback (Header.Dealloc_Traceback).Traceback);
Put (Output_File (Pool), " Memory was allocated at ");
Put_Line (Output_File (Pool), 0, Header.Alloc_Traceback.Traceback);
end if;
else
-- Some sort of codegen problem or heap corruption caused the
-- Size_In_Storage_Elements to be wrongly computed.
-- The code below is all based on the assumption that Header.all
-- is not corrupted, such that the error is non-fatal.
if Header.Block_Size /= Size_In_Storage_Elements then
Put_Line (Output_File (Pool),
"error: Deallocate size "
& Storage_Count'Image (Size_In_Storage_Elements)
& " does not match allocate size "
& Storage_Count'Image (Header.Block_Size));
end if;
if Pool.Low_Level_Traces then
Put (Output_File (Pool),
"info: Deallocated"
& Storage_Count'Image (Size_In_Storage_Elements)
& " bytes at 0x" & Address_Image (Storage_Address)
& " (physically"
& Storage_Count'Image (Header.Block_Size + Minimum_Allocation)
& " bytes at 0x" & Address_Image (Header.Allocation_Address)
& "), at ");
Put_Line (Output_File (Pool), Pool.Stack_Trace_Depth, null,
Deallocate_Label'Address,
Code_Address_For_Deallocate_End);
Put (Output_File (Pool), " Memory was allocated at ");
Put_Line (Output_File (Pool), 0, Header.Alloc_Traceback.Traceback);
end if;
-- Remove this block from the list of used blocks
Previous :=
To_Address (Header.Dealloc_Traceback);
if Previous = System.Null_Address then
Pool.First_Used_Block := Header_Of (Pool.First_Used_Block).Next;
if Pool.First_Used_Block /= System.Null_Address then
Header_Of (Pool.First_Used_Block).Dealloc_Traceback :=
To_Traceback (null);
end if;
else
Header_Of (Previous).Next := Header.Next;
if Header.Next /= System.Null_Address then
Header_Of
(Header.Next).Dealloc_Traceback := To_Address (Previous);
end if;
end if;
-- Update the header
Header.all :=
(Allocation_Address => Header.Allocation_Address,
Alloc_Traceback => Header.Alloc_Traceback,
Dealloc_Traceback => To_Traceback
(Find_Or_Create_Traceback
(Pool, Dealloc,
Size_In_Storage_Elements,
Deallocate_Label'Address,
Code_Address_For_Deallocate_End)),
Next => System.Null_Address,
Block_Size => -Header.Block_Size);
if Pool.Reset_Content_On_Free then
Set_Dead_Beef (Storage_Address, -Header.Block_Size);
end if;
Pool.Logically_Deallocated :=
Pool.Logically_Deallocated + Byte_Count (-Header.Block_Size);
-- Link this free block with the others (at the end of the list, so
-- that we can start releasing the older blocks first later on).
if Pool.First_Free_Block = System.Null_Address then
Pool.First_Free_Block := Storage_Address;
Pool.Last_Free_Block := Storage_Address;
else
Header_Of (Pool.Last_Free_Block).Next := Storage_Address;
Pool.Last_Free_Block := Storage_Address;
end if;
-- Do not physically release the memory here, but in Alloc.
-- See comment there for details.
Unlock_Task.all;
end if;
exception
when others =>
Unlock_Task.all;
raise;
end Deallocate;
--------------------
-- Deallocate_End --
--------------------
-- DO NOT MOVE, this must be right after Deallocate
-- See Allocate_End
-- This is making assumptions about code order that may be invalid ???
procedure Deallocate_End is
begin
<>
Code_Address_For_Deallocate_End := Deallocate_End_Label'Address;
end Deallocate_End;
-----------------
-- Dereference --
-----------------
procedure Dereference
(Pool : in out Debug_Pool;
Storage_Address : Address;
Size_In_Storage_Elements : Storage_Count;
Alignment : Storage_Count)
is
pragma Unreferenced (Alignment, Size_In_Storage_Elements);
Valid : constant Boolean := Is_Valid (Storage_Address);
Header : Allocation_Header_Access;
begin
-- Locking policy: we do not do any locking in this procedure. The
-- tables are only read, not written to, and although a problem might
-- appear if someone else is modifying the tables at the same time, this
-- race condition is not intended to be detected by this storage_pool (a
-- now invalid pointer would appear as valid). Instead, we prefer
-- optimum performance for dereferences.
<>
if not Valid then
if Pool.Raise_Exceptions then
raise Accessing_Not_Allocated_Storage;
else
Put (Output_File (Pool),
"error: Accessing not allocated storage, at ");
Put_Line (Output_File (Pool), Pool.Stack_Trace_Depth, null,
Dereference_Label'Address,
Code_Address_For_Dereference_End);
end if;
else
Header := Header_Of (Storage_Address);
if Header.Block_Size < 0 then
if Pool.Raise_Exceptions then
raise Accessing_Deallocated_Storage;
else
Put (Output_File (Pool),
"error: Accessing deallocated storage, at ");
Put_Line
(Output_File (Pool), Pool.Stack_Trace_Depth, null,
Dereference_Label'Address,
Code_Address_For_Dereference_End);
Put (Output_File (Pool), " First deallocation at ");
Put_Line
(Output_File (Pool),
0, To_Traceback (Header.Dealloc_Traceback).Traceback);
Put (Output_File (Pool), " Initial allocation at ");
Put_Line
(Output_File (Pool),
0, Header.Alloc_Traceback.Traceback);
end if;
end if;
end if;
end Dereference;
---------------------
-- Dereference_End --
---------------------
-- DO NOT MOVE: this must be right after Dereference
-- See Allocate_End
-- This is making assumptions about code order that may be invalid ???
procedure Dereference_End is
begin
<>
Code_Address_For_Dereference_End := Dereference_End_Label'Address;
end Dereference_End;
----------------
-- Print_Info --
----------------
procedure Print_Info
(Pool : Debug_Pool;
Cumulate : Boolean := False;
Display_Slots : Boolean := False;
Display_Leaks : Boolean := False)
is
package Backtrace_Htable_Cumulate is new GNAT.HTable.Static_HTable
(Header_Num => Header,
Element => Traceback_Htable_Elem,
Elmt_Ptr => Traceback_Htable_Elem_Ptr,
Null_Ptr => null,
Set_Next => Set_Next,
Next => Next,
Key => Tracebacks_Array_Access,
Get_Key => Get_Key,
Hash => Hash,
Equal => Equal);
-- This needs a comment ??? probably some of the ones below do too???
Data : Traceback_Htable_Elem_Ptr;
Elem : Traceback_Htable_Elem_Ptr;
Current : System.Address;
Header : Allocation_Header_Access;
K : Traceback_Kind;
begin
Put_Line
("Total allocated bytes : " &
Byte_Count'Image (Pool.Allocated));
Put_Line
("Total logically deallocated bytes : " &
Byte_Count'Image (Pool.Logically_Deallocated));
Put_Line
("Total physically deallocated bytes : " &
Byte_Count'Image (Pool.Physically_Deallocated));
if Pool.Marked_Blocks_Deallocated then
Put_Line ("Marked blocks were physically deallocated. This is");
Put_Line ("potentially dangerous, and you might want to run");
Put_Line ("again with a lower value of Minimum_To_Free");
end if;
Put_Line
("Current Water Mark: " &
Byte_Count'Image
(Pool.Allocated - Pool.Logically_Deallocated
- Pool.Physically_Deallocated));
Put_Line
("High Water Mark: " &
Byte_Count'Image (Pool.High_Water));
Put_Line ("");
if Display_Slots then
Data := Backtrace_Htable.Get_First;
while Data /= null loop
if Data.Kind in Alloc .. Dealloc then
Elem :=
new Traceback_Htable_Elem'
(Traceback => new Tracebacks_Array'(Data.Traceback.all),
Count => Data.Count,
Kind => Data.Kind,
Total => Data.Total,
Next => null);
Backtrace_Htable_Cumulate.Set (Elem);
if Cumulate then
K := (if Data.Kind = Alloc then Indirect_Alloc
else Indirect_Dealloc);
-- Propagate the direct call to all its parents
for T in Data.Traceback'First + 1 .. Data.Traceback'Last loop
Elem := Backtrace_Htable_Cumulate.Get
(Data.Traceback
(T .. Data.Traceback'Last)'Unrestricted_Access);
-- If not, insert it
if Elem = null then
Elem := new Traceback_Htable_Elem'
(Traceback => new Tracebacks_Array'
(Data.Traceback (T .. Data.Traceback'Last)),
Count => Data.Count,
Kind => K,
Total => Data.Total,
Next => null);
Backtrace_Htable_Cumulate.Set (Elem);
-- Properly take into account that the subprograms
-- indirectly called might be doing either allocations
-- or deallocations. This needs to be reflected in the
-- counts.
else
Elem.Count := Elem.Count + Data.Count;
if K = Elem.Kind then
Elem.Total := Elem.Total + Data.Total;
elsif Elem.Total > Data.Total then
Elem.Total := Elem.Total - Data.Total;
else
Elem.Kind := K;
Elem.Total := Data.Total - Elem.Total;
end if;
end if;
end loop;
end if;
Data := Backtrace_Htable.Get_Next;
end if;
end loop;
Put_Line ("List of allocations/deallocations: ");
Data := Backtrace_Htable_Cumulate.Get_First;
while Data /= null loop
case Data.Kind is
when Alloc => Put ("alloc (count:");
when Indirect_Alloc => Put ("indirect alloc (count:");
when Dealloc => Put ("free (count:");
when Indirect_Dealloc => Put ("indirect free (count:");
end case;
Put (Natural'Image (Data.Count) & ", total:" &
Byte_Count'Image (Data.Total) & ") ");
for T in Data.Traceback'Range loop
Put ("0x" & Address_Image (PC_For (Data.Traceback (T))) & ' ');
end loop;
Put_Line ("");
Data := Backtrace_Htable_Cumulate.Get_Next;
end loop;
Backtrace_Htable_Cumulate.Reset;
end if;
if Display_Leaks then
Put_Line ("");
Put_Line ("List of not deallocated blocks:");
-- Do not try to group the blocks with the same stack traces
-- together. This is done by the gnatmem output.
Current := Pool.First_Used_Block;
while Current /= System.Null_Address loop
Header := Header_Of (Current);
Put ("Size: " & Storage_Count'Image (Header.Block_Size) & " at: ");
for T in Header.Alloc_Traceback.Traceback'Range loop
Put ("0x" & Address_Image
(PC_For (Header.Alloc_Traceback.Traceback (T))) & ' ');
end loop;
Put_Line ("");
Current := Header.Next;
end loop;
end if;
end Print_Info;
------------------
-- Storage_Size --
------------------
function Storage_Size (Pool : Debug_Pool) return Storage_Count is
pragma Unreferenced (Pool);
begin
return Storage_Count'Last;
end Storage_Size;
---------------
-- Configure --
---------------
procedure Configure
(Pool : in out Debug_Pool;
Stack_Trace_Depth : Natural := Default_Stack_Trace_Depth;
Maximum_Logically_Freed_Memory : SSC := Default_Max_Freed;
Minimum_To_Free : SSC := Default_Min_Freed;
Reset_Content_On_Free : Boolean := Default_Reset_Content;
Raise_Exceptions : Boolean := Default_Raise_Exceptions;
Advanced_Scanning : Boolean := Default_Advanced_Scanning;
Errors_To_Stdout : Boolean := Default_Errors_To_Stdout;
Low_Level_Traces : Boolean := Default_Low_Level_Traces)
is
begin
Pool.Stack_Trace_Depth := Stack_Trace_Depth;
Pool.Maximum_Logically_Freed_Memory := Maximum_Logically_Freed_Memory;
Pool.Reset_Content_On_Free := Reset_Content_On_Free;
Pool.Raise_Exceptions := Raise_Exceptions;
Pool.Minimum_To_Free := Minimum_To_Free;
Pool.Advanced_Scanning := Advanced_Scanning;
Pool.Errors_To_Stdout := Errors_To_Stdout;
Pool.Low_Level_Traces := Low_Level_Traces;
end Configure;
----------------
-- Print_Pool --
----------------
procedure Print_Pool (A : System.Address) is
Storage : constant Address := A;
Valid : constant Boolean := Is_Valid (Storage);
Header : Allocation_Header_Access;
begin
-- We might get Null_Address if the call from gdb was done
-- incorrectly. For instance, doing a "print_pool(my_var)" passes 0x0,
-- instead of passing the value of my_var
if A = System.Null_Address then
Put_Line
(Standard_Output, "Memory not under control of the storage pool");
return;
end if;
if not Valid then
Put_Line
(Standard_Output, "Memory not under control of the storage pool");
else
Header := Header_Of (Storage);
Put_Line (Standard_Output, "0x" & Address_Image (A)
& " allocated at:");
Put_Line (Standard_Output, 0, Header.Alloc_Traceback.Traceback);
if To_Traceback (Header.Dealloc_Traceback) /= null then
Put_Line (Standard_Output, "0x" & Address_Image (A)
& " logically freed memory, deallocated at:");
Put_Line
(Standard_Output, 0,
To_Traceback (Header.Dealloc_Traceback).Traceback);
end if;
end if;
end Print_Pool;
-----------------------
-- Print_Info_Stdout --
-----------------------
procedure Print_Info_Stdout
(Pool : Debug_Pool;
Cumulate : Boolean := False;
Display_Slots : Boolean := False;
Display_Leaks : Boolean := False)
is
procedure Stdout_Put (S : String);
procedure Stdout_Put_Line (S : String);
-- Wrappers for Put and Put_Line that ensure we always write to stdout
-- instead of the current output file defined in GNAT.IO.
procedure Internal is new Print_Info
(Put_Line => Stdout_Put_Line,
Put => Stdout_Put);
----------------
-- Stdout_Put --
----------------
procedure Stdout_Put (S : String) is
begin
Put_Line (Standard_Output, S);
end Stdout_Put;
---------------------
-- Stdout_Put_Line --
---------------------
procedure Stdout_Put_Line (S : String) is
begin
Put_Line (Standard_Output, S);
end Stdout_Put_Line;
-- Start of processing for Print_Info_Stdout
begin
Internal (Pool, Cumulate, Display_Slots, Display_Leaks);
end Print_Info_Stdout;
------------------
-- Dump_Gnatmem --
------------------
procedure Dump_Gnatmem (Pool : Debug_Pool; File_Name : String) is
type File_Ptr is new System.Address;
function fopen (Path : String; Mode : String) return File_Ptr;
pragma Import (C, fopen);
procedure fwrite
(Ptr : System.Address;
Size : size_t;
Nmemb : size_t;
Stream : File_Ptr);
procedure fwrite
(Str : String;
Size : size_t;
Nmemb : size_t;
Stream : File_Ptr);
pragma Import (C, fwrite);
procedure fputc (C : Integer; Stream : File_Ptr);
pragma Import (C, fputc);
procedure fclose (Stream : File_Ptr);
pragma Import (C, fclose);
Address_Size : constant size_t :=
System.Address'Max_Size_In_Storage_Elements;
-- Size in bytes of a pointer
File : File_Ptr;
Current : System.Address;
Header : Allocation_Header_Access;
Actual_Size : size_t;
Num_Calls : Integer;
Tracebk : Tracebacks_Array_Access;
Dummy_Time : Duration := 1.0;
begin
File := fopen (File_Name & ASCII.NUL, "wb" & ASCII.NUL);
fwrite ("GMEM DUMP" & ASCII.LF, 10, 1, File);
fwrite (Dummy_Time'Address, Duration'Max_Size_In_Storage_Elements, 1,
File);
-- List of not deallocated blocks (see Print_Info)
Current := Pool.First_Used_Block;
while Current /= System.Null_Address loop
Header := Header_Of (Current);
Actual_Size := size_t (Header.Block_Size);
Tracebk := Header.Alloc_Traceback.Traceback;
Num_Calls := Tracebk'Length;
-- (Code taken from memtrack.adb in GNAT's sources)
-- Logs allocation call using the format:
-- 'A' ...
fputc (Character'Pos ('A'), File);
fwrite (Current'Address, Address_Size, 1, File);
fwrite (Actual_Size'Address, size_t'Max_Size_In_Storage_Elements, 1,
File);
fwrite (Dummy_Time'Address, Duration'Max_Size_In_Storage_Elements, 1,
File);
fwrite (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements, 1,
File);
for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
declare
Ptr : System.Address := PC_For (Tracebk (J));
begin
fwrite (Ptr'Address, Address_Size, 1, File);
end;
end loop;
Current := Header.Next;
end loop;
fclose (File);
end Dump_Gnatmem;
-- Package initialization
begin
Allocate_End;
Deallocate_End;
Dereference_End;
end GNAT.Debug_Pools;