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------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- G N A T . D E B U G _ P O O L S -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2005, 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 2, 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. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- -- Boston, MA 02110-1301, USA. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- 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 garantees 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. Initial_Memory_Size : constant Storage_Offset := 2 ** 26; -- 64 Mb -- Initial size of memory that the debug pool can handle. This is used to -- compute the size of the htable used to monitor the blocks, but this is -- dynamic and will grow as needed. Having a bigger size here means a -- longer setup time, but less time spent later on to grow the array. 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. ----------------------- -- Allocations table -- ----------------------- -- This table is indexed on addresses modulo Default_Alignment, and for -- each index it indicates whether that memory block is valid. Its behavior -- is similar to GNAT.Table, except that we need to pack the table to save -- space, so we cannot reuse GNAT.Table as is. -- This table is the reason why all alignments have to be forced to common -- value (Default_Alignment), so that this table can be kept to a -- reasonnable size. type Byte is mod 2 ** System.Storage_Unit; Big_Table_Size : constant Storage_Offset := (Storage_Offset'Last - 1) / Default_Alignment; type Big_Table is array (0 .. Big_Table_Size) of Byte; -- A simple, flat-array type used to access memory bytes (see the comment -- for Valid_Blocks below). -- -- It would be cleaner to represent this as a packed array of Boolean. -- However, we cannot specify pragma Pack for such an array, since the -- total size on a 64 bit machine would be too big (> Integer'Last). -- -- Given an address, we know if it is under control of the debug pool if -- the byte at index: -- ((Address - Edata'Address) / Default_Alignment) -- / Storage_unit -- has the bit -- ((Address - Edata'Address) / Default_Alignment) -- mod Storage_Unit -- set to 1. -- -- See the subprograms Is_Valid and Set_Valid for proper manipulation of -- this array. type Table_Ptr is access Big_Table; function To_Pointer is new Ada.Unchecked_Conversion (System.Address, Table_Ptr); Valid_Blocks : Table_Ptr := null; Valid_Blocks_Size : Storage_Offset := 0; -- These two variables represents a mapping of the currently allocated -- memory. Every time the pool works on an address, we first check that the -- index Address / Default_Alignment is True. If not, this means that this -- address is not under control of the debug pool and thus this is probably -- an invalid memory access (it could also be a general access type). -- -- Note that in fact we never allocate the full size of Big_Table, only a -- slice big enough to manage the currently allocated memory. Edata : System.Address := System.Null_Address; -- Address in memory that matches the index 0 in Valid_Blocks. It is named -- after the symbol _edata, which, on most systems, indicate the lowest -- possible address returned by malloc. Unfortunately, this symbol doesn't -- exist on windows, so we cannot use it instead of this variable. ----------------------- -- 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. procedure Put_Line (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 Standard_Output. 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 function Is_Valid (Storage : System.Address) return Boolean; pragma Inline (Is_Valid); -- Return True if Storage is an address that the debug pool has under its -- control. 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). This procedure will -- reallocate the table Valid_Blocks as needed. 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 exludes 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; -------------- -- Put_Line -- -------------- procedure Put_Line (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 ("0x" & Address_Image (PC_For (Tr (J))) & ' '); end loop; Put (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; -------------- -- Is_Valid -- -------------- function Is_Valid (Storage : System.Address) return Boolean is Offset : constant Storage_Offset := (Storage - Edata) / Default_Alignment; Bit : constant Byte := 2 ** Natural (Offset mod System.Storage_Unit); begin return (Storage mod Default_Alignment) = 0 and then Offset >= 0 and then Offset < Valid_Blocks_Size * Storage_Unit and then (Valid_Blocks (Offset / Storage_Unit) and Bit) /= 0; end Is_Valid; --------------- -- Set_Valid -- --------------- procedure Set_Valid (Storage : System.Address; Value : Boolean) is Offset : Storage_Offset; Bit : Byte; Bytes : Storage_Offset; Tmp : constant Table_Ptr := Valid_Blocks; Edata_Align : constant Storage_Offset := Default_Alignment * Storage_Unit; procedure Memset (A : Address; C : Integer; N : size_t); pragma Import (C, Memset, "memset"); procedure Memmove (Dest, Src : Address; N : size_t); pragma Import (C, Memmove, "memmove"); begin -- Allocate, or reallocate, the valid blocks table as needed. We start -- with a size big enough to handle Initial_Memory_Size bytes of memory, -- to avoid too many reallocations. The table will typically be around -- 16Mb in that case, which is still small enough. if Valid_Blocks_Size = 0 then Valid_Blocks_Size := (Initial_Memory_Size / Default_Alignment) / Storage_Unit; Valid_Blocks := To_Pointer (Alloc (size_t (Valid_Blocks_Size))); Edata := Storage; -- Reset the memory using memset, which is much faster than the -- standard Ada code with "when others" Memset (Valid_Blocks.all'Address, 0, size_t (Valid_Blocks_Size)); end if; -- First case : the new address is outside of the current scope of -- Valid_Blocks, before the current start address. We need to reallocate -- the table accordingly. This should be a rare occurence, since in most -- cases, the first allocation will also have the lowest address. But -- there is no garantee... if Storage < Edata then -- The difference between the new Edata and the current one must be -- a multiple of Default_Alignment * Storage_Unit, so that the bit -- representing an address in Valid_Blocks are kept the same. Offset := ((Edata - Storage) / Edata_Align + 1) * Edata_Align; Offset := Offset / Default_Alignment; Bytes := Offset / Storage_Unit; Valid_Blocks := To_Pointer (Alloc (Size => size_t (Valid_Blocks_Size + Bytes))); Memmove (Dest => Valid_Blocks.all'Address + Bytes, Src => Tmp.all'Address, N => size_t (Valid_Blocks_Size)); Memset (A => Valid_Blocks.all'Address, C => 0, N => size_t (Bytes)); Free (Tmp.all'Address); Valid_Blocks_Size := Valid_Blocks_Size + Bytes; -- Take into the account the new start address Edata := Storage - Edata_Align + (Edata - Storage) mod Edata_Align; end if; -- Second case : the new address is outside of the current scope of -- Valid_Blocks, so we have to grow the table as appropriate. -- Note: it might seem more natural for the following statement to -- be written: -- Offset := (Storage - Edata) / Default_Alignment; -- but that won't work since Storage_Offset is signed, and it is -- possible to subtract a small address from a large address and -- get a negative value. This may seem strange, but it is quite -- specifically allowed in the RM, and is what most implementations -- including GNAT actually do. Hence the conversion to Integer_Address -- which is a full range modular type, not subject to this glitch. Offset := Storage_Offset ((To_Integer (Storage) - To_Integer (Edata)) / Default_Alignment); if Offset >= Valid_Blocks_Size * System.Storage_Unit then Bytes := Valid_Blocks_Size; loop Bytes := 2 * Bytes; exit when Offset <= Bytes * System.Storage_Unit; end loop; Valid_Blocks := To_Pointer (Realloc (Ptr => Valid_Blocks.all'Address, Size => size_t (Bytes))); Memset (Valid_Blocks.all'Address + Valid_Blocks_Size, 0, size_t (Bytes - Valid_Blocks_Size)); Valid_Blocks_Size := Bytes; end if; Bit := 2 ** Natural (Offset mod System.Storage_Unit); Bytes := Offset / Storage_Unit; -- Then set the value as valid if Value then Valid_Blocks (Bytes) := Valid_Blocks (Bytes) or Bit; else Valid_Blocks (Bytes) := Valid_Blocks (Bytes) and (not Bit); end if; end Set_Valid; -------------- -- 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(). P : Ptr; Current : Byte_Count; Trace : Traceback_Htable_Elem_Ptr; begin <<Allocate_Label>> 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 a -- 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 (ie 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. begin P := new Local_Storage_Array; exception when Storage_Error => Free_Physically (Pool); P := new Local_Storage_Array; end; Storage_Address := System.Null_Address + Default_Alignment * (((P.all'Address + Default_Alignment - 1) - System.Null_Address) / Default_Alignment) + Header_Offset; 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); -- 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 <<Allocate_End_Label>> 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 -- reference 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; 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 if In_Use then To_Byte (A).all := In_Use_Mark; else To_Byte (A).all := Free_Mark; end if; 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_Marks; -- Reset the mark for each freed block 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 <<Deallocate_Label>> 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 ("error: Freeing not allocated storage, at "); Put_Line (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 ("error: Freeing already deallocated storage, at "); Put_Line (Pool.Stack_Trace_Depth, null, Deallocate_Label'Address, Code_Address_For_Deallocate_End); Put (" Memory already deallocated at "); Put_Line (0, To_Traceback (Header.Dealloc_Traceback).Traceback); Put (" Memory was allocated at "); Put_Line (0, Header.Alloc_Traceback.Traceback); end if; else -- Remove this block from the list of used blocks Previous := To_Address (Header_Of (Storage_Address).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_Of (Storage_Address).Next; if Header_Of (Storage_Address).Next /= System.Null_Address then Header_Of (Header_Of (Storage_Address).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 => -Size_In_Storage_Elements); if Pool.Reset_Content_On_Free then Set_Dead_Beef (Storage_Address, Size_In_Storage_Elements); end if; Pool.Logically_Deallocated := Pool.Logically_Deallocated + Byte_Count (Size_In_Storage_Elements); -- 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 procedure Deallocate_End is begin <<Deallocate_End_Label>> 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. <<Dereference_Label>> if not Valid then if Pool.Raise_Exceptions then raise Accessing_Not_Allocated_Storage; else Put ("error: Accessing not allocated storage, at "); Put_Line (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 ("error: Accessing deallocated storage, at "); Put_Line (Pool.Stack_Trace_Depth, null, Dereference_Label'Address, Code_Address_For_Dereference_End); Put (" First deallocation at "); Put_Line (0, To_Traceback (Header.Dealloc_Traceback).Traceback); Put (" Initial allocation at "); Put_Line (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 procedure Dereference_End is begin <<Dereference_End_Label>> 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 dangereous, 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 if Data.Kind = Alloc then K := Indirect_Alloc; else K := Indirect_Dealloc; end if; -- 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) 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; 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 ("Memory not under control of the storage pool"); return; end if; if not Valid then Put_Line ("Memory not under control of the storage pool"); else Header := Header_Of (Storage); Put_Line ("0x" & Address_Image (A) & " allocated at:"); Put_Line (0, Header.Alloc_Traceback.Traceback); if To_Traceback (Header.Dealloc_Traceback) /= null then Put_Line ("0x" & Address_Image (A) & " logically freed memory, deallocated at:"); Put_Line (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 Internal is new Print_Info (Put_Line => GNAT.IO.Put_Line, Put => GNAT.IO.Put); 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; begin File := fopen (File_Name & ASCII.NUL, "wb" & ASCII.NUL); fwrite ("GMEM DUMP" & ASCII.LF, 10, 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' <mem addr> <size chunk> <len backtrace> <addr1> ... <addrn> 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 (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; begin Allocate_End; Deallocate_End; Dereference_End; end GNAT.Debug_Pools;
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