{ This unit is an extended heaptrc unit.
}
unit MemCheck;

{$MODE ObjFPC}

interface

{ define EXTRA to add more
  tests :
   - keep all memory after release and
   check by CRC value if not changed after release
   WARNING this needs extremely much memory (PM) }

{$DEFINE Extra}

{$inline off}// inline off for stack traces

// additions for codetools
{$DEFINE MC_Interface}
{$i memcheck_laz.inc}
{$UNDEF MC_Interface}

{$checkpointer off}
{$goto on}

{$if defined(win32) or defined(wince)}
  {$define windows}
{$endif}

Procedure DumpHeap;

{ define EXTRA to add more
  tests :
   - keep all memory after release and
   check by CRC value if not changed after release
   WARNING this needs extremely much memory (PM) }

type
   tFillExtraInfoProc = procedure(p : pointer);
   tdisplayextrainfoProc = procedure (var ptext : text;p : pointer);

{ Allows to add info pre memory block, see ppheap.pas of the compiler
  for example source }
procedure SetHeapExtraInfo(size : ptruint;fillproc : tfillextrainfoproc;displayproc : tdisplayextrainfoproc);

{ Redirection of the output to a file }
procedure SetHeapTraceOutput(const name : string);

const
  { tracing level
    splitted in two if memory is released !! }
{$ifdef EXTRA}
  tracesize = 32;
{$else EXTRA}
  tracesize = 16;
{$endif EXTRA}
  { install heaptrc memorymanager }
  useheaptrace : boolean=true;
  { less checking }
  quicktrace : boolean=false;
  { calls halt() on error by default !! }
  HaltOnError : boolean = true;
  { Halt on exit if any memory was not freed }
  HaltOnNotReleased : boolean = false;

  { set this to true if you suspect that memory
    is freed several times }
{$ifdef EXTRA}
  keepreleased : boolean=true;
{$else EXTRA}
  keepreleased : boolean=false;
{$endif EXTRA}
  { add a small footprint at the end of memory blocks, this
    can check for memory overwrites at the end of a block }
  add_tail : boolean = true;
  { put crc in sig
    this allows to test for writing into that part }
  usecrc : boolean = true;


implementation

// additions for codetools
{$DEFINE MC_ImplementationStart}
{$i memcheck_laz.inc}
{$UNDEF MC_ImplementationStart}

const
  { allows to add custom info in heap_mem_info, this is the size that will
    be allocated for this information }
  extra_info_size : ptruint = 0;
  exact_info_size : ptruint = 0;
  EntryMemUsed    : ptruint = 0;
  { function to fill this info up }
  fill_extra_info_proc : TFillExtraInfoProc = nil;
  display_extra_info_proc : TDisplayExtraInfoProc = nil;
  { indicates where the output will be redirected }
  { only set using environment variables          }
  outputstr : shortstring = '';

type
  pheap_extra_info = ^theap_extra_info;
  theap_extra_info = record
    check       : cardinal;  { used to check if the procvar is still valid }
    fillproc    : tfillextrainfoProc;
    displayproc : tdisplayextrainfoProc;
    data : record
           end;
  end;

  ppheap_mem_info = ^pheap_mem_info;
  pheap_mem_info = ^theap_mem_info;

  { warning the size of theap_mem_info
    must be a multiple of 8
    because otherwise you will get
    problems when releasing the usual memory part !!
    sizeof(theap_mem_info = 16+tracesize*4 so
    tracesize must be even !! PM }
  theap_mem_info = record
    previous,
    next     : pheap_mem_info;
    todolist : ppheap_mem_info;
    todonext : pheap_mem_info;
    size     : ptruint;
    sig      : longword;
{$ifdef EXTRA}
    release_sig : longword;
    prev_valid  : pheap_mem_info;
{$endif EXTRA}
    calls    : array [1..tracesize] of pointer;
    exact_info_size : word;
    extra_info_size : word;
    extra_info      : pheap_extra_info;
  end;

  pheap_info = ^theap_info;
  theap_info = record
{$ifdef EXTRA}
    heap_valid_first,
    heap_valid_last : pheap_mem_info;
{$endif EXTRA}
    heap_mem_root : pheap_mem_info;
    heap_free_todo : pheap_mem_info;
    getmem_cnt,
    freemem_cnt   : ptruint;
    getmem_size,
    freemem_size  : ptruint;
    getmem8_size,
    freemem8_size : ptruint;
    error_in_heap : boolean;
    inside_trace_getmem : boolean;
  end;

var
  useownfile : boolean;
  ownfile : text;
{$ifdef EXTRA}
  error_file : text;
{$endif EXTRA}
  main_orig_todolist: ppheap_mem_info;
  main_relo_todolist: ppheap_mem_info;
  orphaned_info: theap_info;
  todo_lock: trtlcriticalsection;
threadvar
  heap_info: theap_info;

{*****************************************************************************
                                   Crc 32
*****************************************************************************}

var
  Crc32Tbl : array[0..255] of longword;

procedure MakeCRC32Tbl;
var
  crc : longword;
  i,n : byte;
begin
  for i:=0 to 255 do
   begin
     crc:=i;
     for n:=1 to 8 do
      if odd(crc) then
       crc:=(crc shr 1) xor $edb88320
      else
       crc:=crc shr 1;
     Crc32Tbl[i]:=crc;
   end;
end;


Function UpdateCrc32(InitCrc:longword;var InBuf;InLen:ptruint):longword;
var
  i : ptruint;
  p : pchar;
begin
  p:=@InBuf;
  for i:=1 to InLen do
   begin
     InitCrc:=Crc32Tbl[byte(InitCrc) xor byte(p^)] xor (InitCrc shr 8);
     inc(p);
   end;
  UpdateCrc32:=InitCrc;
end;

Function calculate_sig(p : pheap_mem_info) : longword;
var
   crc : longword;
   pl : pptruint;
begin
   crc:=cardinal($ffffffff);
   crc:=UpdateCrc32(crc,p^.size,sizeof(ptruint));
   crc:=UpdateCrc32(crc,p^.calls,tracesize*sizeof(ptruint));
   if p^.extra_info_size>0 then
     crc:=UpdateCrc32(crc,p^.extra_info^,p^.exact_info_size);
   if add_tail then
     begin
        { Check also 4 bytes just after allocation !! }
        pl:=pointer(p)+p^.extra_info_size+sizeof(theap_mem_info)+p^.size;
        crc:=UpdateCrc32(crc,pl^,sizeof(ptruint));
     end;
   calculate_sig:=crc;
end;

{$ifdef EXTRA}
Function calculate_release_sig(p : pheap_mem_info) : longword;
var
   crc : longword;
   pl : pptruint;
begin
   crc:=$ffffffff;
   crc:=UpdateCrc32(crc,p^.size,sizeof(ptruint));
   crc:=UpdateCrc32(crc,p^.calls,tracesize*sizeof(ptruint));
   if p^.extra_info_size>0 then
     crc:=UpdateCrc32(crc,p^.extra_info^,p^.exact_info_size);
   { Check the whole of the whole allocation }
   pl:=pointer(p)+p^.extra_info_size+sizeof(theap_mem_info);
   crc:=UpdateCrc32(crc,pl^,p^.size);
   { Check also 4 bytes just after allocation !! }
   if add_tail then
     begin
        { Check also 4 bytes just after allocation !! }
        pl:=pointer(p)+p^.extra_info_size+sizeof(theap_mem_info)+p^.size;
        crc:=UpdateCrc32(crc,pl^,sizeof(ptruint));
     end;
   calculate_release_sig:=crc;
end;
{$endif EXTRA}


{*****************************************************************************
                                Helpers
*****************************************************************************}

function InternalFreeMemSize(loc_info: pheap_info; p: pointer; pp: pheap_mem_info;
  size: ptruint; release_todo_lock: boolean): ptruint; forward;
function TraceFreeMem(p: pointer): ptruint; forward;

procedure call_stack(pp : pheap_mem_info;var ptext : text);
var
  i  : ptruint;
begin
  writeln(ptext,'Call trace for block $',hexstr(pointer(pp)+sizeof(theap_mem_info)),' size ',pp^.size);
  for i:=1 to tracesize do
   if pp^.calls[i]<>nil then
     writeln(ptext,BackTraceStrFunc(pp^.calls[i]));
  { the check is done to be sure that the procvar is not overwritten }
  if assigned(pp^.extra_info) and
     (pp^.extra_info^.check=$12345678) and
     assigned(pp^.extra_info^.displayproc) then
   pp^.extra_info^.displayproc(ptext,@pp^.extra_info^.data);
end;


procedure call_free_stack(pp : pheap_mem_info;var ptext : text);
var
  i  : ptruint;
begin
  writeln(ptext,'Call trace for block at $',hexstr(pointer(pp)+sizeof(theap_mem_info)),' size ',pp^.size);
  for i:=1 to tracesize div 2 do
   if pp^.calls[i]<>nil then
     writeln(ptext,BackTraceStrFunc(pp^.calls[i]));
  writeln(ptext,' was released at ');
  for i:=(tracesize div 2)+1 to tracesize do
   if pp^.calls[i]<>nil then
     writeln(ptext,BackTraceStrFunc(pp^.calls[i]));
  { the check is done to be sure that the procvar is not overwritten }
  if assigned(pp^.extra_info) and
     (pp^.extra_info^.check=$12345678) and
     assigned(pp^.extra_info^.displayproc) then
   pp^.extra_info^.displayproc(ptext,@pp^.extra_info^.data);
end;


procedure dump_already_free(p : pheap_mem_info;var ptext : text);
begin
  Writeln(ptext,'Marked memory at $',HexStr(pointer(p)+sizeof(theap_mem_info)),' released');
  call_free_stack(p,ptext);
  Writeln(ptext,'freed again at');
  dump_stack(ptext,get_caller_frame(get_frame));
end;

procedure dump_error(p : pheap_mem_info;var ptext : text);
begin
  Writeln(ptext,'Marked memory at $',HexStr(pointer(p)+sizeof(theap_mem_info)),' invalid');
  Writeln(ptext,'Wrong signature $',hexstr(p^.sig,8),' instead of ',hexstr(calculate_sig(p),8));
  dump_stack(ptext,get_caller_frame(get_frame));
end;

{$ifdef EXTRA}
procedure dump_change_after(p : pheap_mem_info;var ptext : text);
 var pp : pchar;
     i : ptruint;
begin
  Writeln(ptext,'Marked memory at $',HexStr(pointer(p)+sizeof(theap_mem_info)),' invalid');
  Writeln(ptext,'Wrong release CRC $',hexstr(p^.release_sig,8),' instead of ',hexstr(calculate_release_sig(p),8));
  Writeln(ptext,'This memory was changed after call to freemem !');
  call_free_stack(p,ptext);
  pp:=pointer(p)+sizeof(theap_mem_info);
  for i:=0 to p^.size-1 do
    if byte(pp[i])<>$F0 then
      Writeln(ptext,'offset',i,':$',hexstr(i,2*sizeof(pointer)),'"',pp[i],'"');
end;
{$endif EXTRA}

procedure dump_wrong_size(p : pheap_mem_info;size : ptruint;var ptext : text);
begin
  Writeln(ptext,'Marked memory at $',HexStr(pointer(p)+sizeof(theap_mem_info)),' invalid');
  Writeln(ptext,'Wrong size : ',p^.size,' allocated ',size,' freed');
  dump_stack(ptext,get_caller_frame(get_frame));
  { the check is done to be sure that the procvar is not overwritten }
  if assigned(p^.extra_info) and
     (p^.extra_info^.check=$12345678) and
     assigned(p^.extra_info^.displayproc) then
   p^.extra_info^.displayproc(ptext,@p^.extra_info^.data);
  call_stack(p,ptext);
end;

function is_in_getmem_list (loc_info: pheap_info; p : pheap_mem_info) : boolean;
var
  i  : ptruint;
  pp : pheap_mem_info;
begin
  is_in_getmem_list:=false;
  pp:=loc_info^.heap_mem_root;
  i:=0;
  while pp<>nil do
   begin
     if ((pp^.sig<>$DEADBEEF) or usecrc) and
        ((pp^.sig<>calculate_sig(pp)) or not usecrc) and
        (pp^.sig <>$AAAAAAAA) then
      begin
        if useownfile then
          writeln(ownfile,'error in linked list of heap_mem_info')
        else
          writeln(stderr,'error in linked list of heap_mem_info');
        RunError(204);
      end;
     if pp=p then
      is_in_getmem_list:=true;
     pp:=pp^.previous;
     inc(i);
     if i>loc_info^.getmem_cnt-loc_info^.freemem_cnt then begin
       if useownfile then
         writeln(ownfile,'error in linked list of heap_mem_info')
       else
         writeln(stderr,'error in linked list of heap_mem_info');
       RunError(204);
     end;
   end;
end;

procedure finish_heap_free_todo_list(loc_info: pheap_info);
var
  bp: pointer;
  pp: pheap_mem_info;
  list: ppheap_mem_info;
begin
  list := @loc_info^.heap_free_todo;
  repeat
    pp := list^;
    list^ := list^^.todonext;
    bp := pointer(pp)+sizeof(theap_mem_info);
    InternalFreeMemSize(loc_info,bp,pp,pp^.size,false);
  until list^ = nil;
end;

procedure try_finish_heap_free_todo_list(loc_info: pheap_info);
begin
  if loc_info^.heap_free_todo <> nil then
  begin
    entercriticalsection(todo_lock);
    finish_heap_free_todo_list(loc_info);
    leavecriticalsection(todo_lock);
  end;
end;


{*****************************************************************************
                               TraceGetMem
*****************************************************************************}

Function TraceGetMem(size:ptruint):pointer;
var
  allocsize,i : ptruint;
  oldbp,
  bp : pointer;
  pl : pdword;
  p  : pointer;
  pp : pheap_mem_info;
  loc_info: pheap_info;
begin
  loc_info := @heap_info;
  try_finish_heap_free_todo_list(loc_info);
  inc(loc_info^.getmem_size,size);
  inc(loc_info^.getmem8_size,(size+7) and not 7);
{ Do the real GetMem, but alloc also for the info block }
{$ifdef cpuarm}
  allocsize:=(size + 3) and not 3+sizeof(theap_mem_info)+extra_info_size;
{$else cpuarm}
  allocsize:=size+sizeof(theap_mem_info)+extra_info_size;
{$endif cpuarm}
  if add_tail then
    inc(allocsize,sizeof(ptruint));
  { if ReturnNilIfGrowHeapFails is true
    SysGetMem can return nil }
  p:=SysGetMem(allocsize);
  if (p=nil) then
    begin
      TraceGetMem:=nil;
      exit;
    end;
  pp:=pheap_mem_info(p);
  inc(p,sizeof(theap_mem_info));
{ Create the info block }
  pp^.sig:=$DEADBEEF;
  pp^.todolist:=@loc_info^.heap_free_todo;
  pp^.todonext:=nil;
  pp^.size:=size;
  pp^.extra_info_size:=extra_info_size;
  pp^.exact_info_size:=exact_info_size;
  {
    the end of the block contains:
    <tail>   4 bytes
    <extra_info>   X bytes
  }
  if extra_info_size>0 then
   begin
     pp^.extra_info:=pointer(pp)+allocsize-extra_info_size;
     fillchar(pp^.extra_info^,extra_info_size,0);
     pp^.extra_info^.check:=$12345678;
     pp^.extra_info^.fillproc:=fill_extra_info_proc;
     pp^.extra_info^.displayproc:=display_extra_info_proc;
     if assigned(fill_extra_info_proc) then
      begin
        loc_info^.inside_trace_getmem:=true;
        fill_extra_info_proc(@pp^.extra_info^.data);
        loc_info^.inside_trace_getmem:=false;
      end;
   end
  else
   pp^.extra_info:=nil;
  if add_tail then
    begin
      pl:=pointer(pp)+allocsize-pp^.extra_info_size-sizeof(ptruint);
{$ifdef FPC_SUPPORTS_UNALIGNED}
      unaligned(pl^):=$DEADBEEF;
{$else FPC_SUPPORTS_UNALIGNED}
      pl^:=$DEADBEEF;
{$endif FPC_SUPPORTS_UNALIGNED}
    end;
  { clear the memory }
  fillchar(p^,size,#255);
  { retrieve backtrace info }
  bp:=get_caller_frame(get_frame);
  for i:=1 to tracesize do
   begin
     pp^.calls[i]:=get_caller_addr(bp);
     oldbp:=bp;
     bp:=get_caller_frame(bp);
     if (bp<oldbp) or (bp>(StackBottom + StackLength)) then
       bp:=nil;
   end;
  { insert in the linked list }
  if loc_info^.heap_mem_root<>nil then
   loc_info^.heap_mem_root^.next:=pp;
  pp^.previous:=loc_info^.heap_mem_root;
  pp^.next:=nil;
{$ifdef EXTRA}
  pp^.prev_valid:=loc_info^.heap_valid_last;
  loc_info^.heap_valid_last:=pp;
  if not assigned(loc_info^.heap_valid_first) then
    loc_info^.heap_valid_first:=pp;
{$endif EXTRA}
  loc_info^.heap_mem_root:=pp;
  { must be changed before fill_extra_info is called
    because checkpointer can be called from within
    fill_extra_info PM }
  inc(loc_info^.getmem_cnt);
  { update the signature }
  if usecrc then
    pp^.sig:=calculate_sig(pp);
  TraceGetmem:=p;
end;


{*****************************************************************************
                                TraceFreeMem
*****************************************************************************}

function CheckFreeMemSize(loc_info: pheap_info; pp: pheap_mem_info;
  size, ppsize: ptruint): boolean;
var
  i: ptruint;
  bp : pointer;
  ptext : ^text;
{$ifdef EXTRA}
  pp2 : pheap_mem_info;
{$endif}
begin
  if useownfile then
    ptext:=@ownfile
  else
    ptext:=@stderr;
  inc(loc_info^.freemem_size,size);
  inc(loc_info^.freemem8_size,(size+7) and not 7);
  if not quicktrace then
    begin
      if not(is_in_getmem_list(loc_info, pp)) then
       RunError(204);
    end;
  if (pp^.sig=$AAAAAAAA) and not usecrc then
    begin
       loc_info^.error_in_heap:=true;
       dump_already_free(pp,ptext^);
       if haltonerror then halt(1);
    end
  else if ((pp^.sig<>$DEADBEEF) or usecrc) and
        ((pp^.sig<>calculate_sig(pp)) or not usecrc) then
    begin
       loc_info^.error_in_heap:=true;
       dump_error(pp,ptext^);
{$ifdef EXTRA}
       dump_error(pp,error_file);
{$endif EXTRA}
       { don't release anything in this case !! }
       if haltonerror then halt(1);
       exit;
    end
  else if pp^.size<>size then
    begin
       loc_info^.error_in_heap:=true;
       dump_wrong_size(pp,size,ptext^);
{$ifdef EXTRA}
       dump_wrong_size(pp,size,error_file);
{$endif EXTRA}
       if haltonerror then halt(1);
       { don't release anything in this case !! }
       exit;
    end;
  { now it is released !! }
  pp^.sig:=$AAAAAAAA;
  if not keepreleased then
    begin
       if pp^.next<>nil then
         pp^.next^.previous:=pp^.previous;
       if pp^.previous<>nil then
         pp^.previous^.next:=pp^.next;
       if pp=loc_info^.heap_mem_root then
         loc_info^.heap_mem_root:=loc_info^.heap_mem_root^.previous;
    end
  else
    begin
       bp:=get_caller_frame(get_frame);
       for i:=(tracesize div 2)+1 to tracesize do
        begin
          if bp<>nil then begin
            pp^.calls[i]:=get_caller_addr(bp);
            bp:=get_caller_frame(bp);
          end else begin
            pp^.calls[i]:=nil;
          end;
        end;
    end;
  inc(loc_info^.freemem_cnt);
  { clear the memory, $F0 will lead to GFP if used as pointer ! }
  fillchar((pointer(pp)+sizeof(theap_mem_info))^,size,#240);
  { this way we keep all info about all released memory !! }
  if keepreleased then
    begin
{$ifdef EXTRA}
       { We want to check if the memory was changed after release !! }
       pp^.release_sig:=calculate_release_sig(pp);
       if pp=loc_info^.heap_valid_last then
         begin
            loc_info^.heap_valid_last:=pp^.prev_valid;
            if pp=loc_info^.heap_valid_first then
              loc_info^.heap_valid_first:=nil;
            exit(false);
         end;
       pp2:=loc_info^.heap_valid_last;
       while assigned(pp2) do
         begin
            if pp2^.prev_valid=pp then
              begin
                 pp2^.prev_valid:=pp^.prev_valid;
                 if pp=loc_info^.heap_valid_first then
                   loc_info^.heap_valid_first:=pp2;
                 exit(false);
              end
            else
              pp2:=pp2^.prev_valid;
         end;
{$endif EXTRA}
       exit(false);
    end;
  CheckFreeMemSize:=true;
end;

function InternalFreeMemSize(loc_info: pheap_info; p: pointer; pp: pheap_mem_info;
  size: ptruint; release_todo_lock: boolean): ptruint;
var
  i,ppsize : ptruint;
  extra_size: ptruint;
  release_mem: boolean;
begin
  { save old values }
  extra_size:=pp^.extra_info_size;
  ppsize:= size+sizeof(theap_mem_info)+pp^.extra_info_size;
  if add_tail then
    inc(ppsize,sizeof(ptruint));
  { do various checking }
  release_mem := CheckFreeMemSize(loc_info, pp, size, ppsize);
  if release_todo_lock then
    leavecriticalsection(todo_lock);
  if release_mem then
  begin
    { release the normal memory at least }
    i:=SysFreeMemSize(pp,ppsize);
    { return the correct size }
    dec(i,sizeof(theap_mem_info)+extra_size);
    if add_tail then
      dec(i,sizeof(ptruint));
    InternalFreeMemSize:=i;
  end else
    InternalFreeMemSize:=size;
end;

function TraceFreeMemSize(p:pointer;size:ptruint):ptruint;
var
  loc_info: pheap_info;
  pp: pheap_mem_info;
  release_lock: boolean;
begin
  if p=nil then
    begin
      TraceFreeMemSize:=0;
      exit;
    end;
  loc_info:=@heap_info;
  pp:=pheap_mem_info(p-sizeof(theap_mem_info));
  release_lock:=false;
  if @loc_info^.heap_free_todo <> pp^.todolist then
  begin
    if pp^.todolist = main_orig_todolist then
      pp^.todolist := main_relo_todolist;
    entercriticalsection(todo_lock);
    release_lock:=true;
    if pp^.todolist = @orphaned_info.heap_free_todo then
    begin
      loc_info := @orphaned_info;
    end else
    if pp^.todolist <> @loc_info^.heap_free_todo then
    begin
      { allocated in different heap, push to that todolist }
      pp^.todonext := pp^.todolist^;
      pp^.todolist^ := pp;
      TraceFreeMemSize := pp^.size;
      leavecriticalsection(todo_lock);
      exit;
    end;
  end;
  TraceFreeMemSize:=InternalFreeMemSize(loc_info,p,pp,size,release_lock);
end;


function TraceMemSize(p:pointer):ptruint;
var
  pp : pheap_mem_info;
begin
  pp:=pheap_mem_info(p-sizeof(theap_mem_info));
  TraceMemSize:=pp^.size;
end;


function TraceFreeMem(p:pointer):ptruint;
var
  l  : ptruint;
  pp : pheap_mem_info;
begin
  if p=nil then
    begin
      TraceFreeMem:=0;
      exit;
    end;
  pp:=pheap_mem_info(p-sizeof(theap_mem_info));
  l:=SysMemSize(pp);
  dec(l,sizeof(theap_mem_info)+pp^.extra_info_size);
  if add_tail then
   dec(l,sizeof(ptruint));
  { this can never happend normaly }
  if pp^.size>l then
   begin
     if useownfile then
       dump_wrong_size(pp,l,ownfile)
     else
       dump_wrong_size(pp,l,stderr);

{$ifdef EXTRA}
     dump_wrong_size(pp,l,error_file);
{$endif EXTRA}
   end;
  TraceFreeMem:=TraceFreeMemSize(p,pp^.size);
end;


{*****************************************************************************
                                ReAllocMem
*****************************************************************************}

function TraceReAllocMem(var p:pointer;size:ptruint):Pointer;
var
  newP: pointer;
  allocsize,
  movesize,
  i  : ptruint;
  oldbp,
  bp : pointer;
  pl : pdword;
  pp : pheap_mem_info;
  oldsize,
  oldextrasize,
  oldexactsize : ptruint;
  old_fill_extra_info_proc : tfillextrainfoproc;
  old_display_extra_info_proc : tdisplayextrainfoproc;
  loc_info: pheap_info;
begin
{ Free block? }
  if size=0 then
   begin
     if p<>nil then
      TraceFreeMem(p);
     p:=nil;
     TraceReallocMem:=P;
     exit;
   end;
{ Allocate a new block? }
  if p=nil then
   begin
     p:=TraceGetMem(size);
     TraceReallocMem:=P;
     exit;
   end;
{ Resize block }
  loc_info:=@heap_info;
  pp:=pheap_mem_info(p-sizeof(theap_mem_info));
  { test block }
  if ((pp^.sig<>$DEADBEEF) or usecrc) and
     ((pp^.sig<>calculate_sig(pp)) or not usecrc) then
   begin
     loc_info^.error_in_heap:=true;
     if useownfile then
       dump_error(pp,ownfile)
     else
       dump_error(pp,stderr);
{$ifdef EXTRA}
     dump_error(pp,error_file);
{$endif EXTRA}
     { don't release anything in this case !! }
     if haltonerror then halt(1);
     exit;
   end;
  { save info }
  oldsize:=pp^.size;
  oldextrasize:=pp^.extra_info_size;
  oldexactsize:=pp^.exact_info_size;
  if pp^.extra_info_size>0 then
   begin
     old_fill_extra_info_proc:=pp^.extra_info^.fillproc;
     old_display_extra_info_proc:=pp^.extra_info^.displayproc;
   end;
  { Do the real ReAllocMem, but alloc also for the info block }
{$ifdef cpuarm}
  allocsize:=(size + 3) and not 3+sizeof(theap_mem_info)+pp^.extra_info_size;
{$else cpuarm}
  allocsize:=size+sizeof(theap_mem_info)+pp^.extra_info_size;
{$endif cpuarm}
  if add_tail then
   inc(allocsize,sizeof(ptruint));
  { Try to resize the block, if not possible we need to do a
    getmem, move data, freemem }
  if not SysTryResizeMem(pp,allocsize) then
   begin
     { get a new block }
     newP := TraceGetMem(size);
     { move the data }
     if newP <> nil then
      begin
        movesize:=TraceMemSize(p);
        {if the old size is larger than the new size,
         move only the new size}
        if movesize>size then
          movesize:=size;
        move(p^,newP^,movesize);
      end;
     { release p }
     traceFreeMem(p);
     { return the new pointer }
     p:=newp;
     traceReAllocMem := newp;
     exit;
   end;
{ Recreate the info block }
  pp^.sig:=$DEADBEEF;
  pp^.size:=size;
  pp^.extra_info_size:=oldextrasize;
  pp^.exact_info_size:=oldexactsize;
  { add the new extra_info and tail }
  if pp^.extra_info_size>0 then
   begin
     pp^.extra_info:=pointer(pp)+allocsize-pp^.extra_info_size;
     fillchar(pp^.extra_info^,extra_info_size,0);
     pp^.extra_info^.check:=$12345678;
     pp^.extra_info^.fillproc:=old_fill_extra_info_proc;
     pp^.extra_info^.displayproc:=old_display_extra_info_proc;
     if assigned(pp^.extra_info^.fillproc) then
      pp^.extra_info^.fillproc(@pp^.extra_info^.data);
   end
  else
   pp^.extra_info:=nil;
  if add_tail then
    begin
      pl:=pointer(pp)+allocsize-pp^.extra_info_size-sizeof(ptruint);
{$ifdef FPC_SUPPORTS_UNALIGNED}
      unaligned(pl^):=$DEADBEEF;
{$else FPC_SUPPORTS_UNALIGNED}
      pl^:=$DEADBEEF;
{$endif FPC_SUPPORTS_UNALIGNED}
    end;
  { adjust like a freemem and then a getmem, so you get correct
    results in the summary display }
  inc(loc_info^.freemem_size,oldsize);
  inc(loc_info^.freemem8_size,(oldsize+7) and not 7);
  inc(loc_info^.getmem_size,size);
  inc(loc_info^.getmem8_size,(size+7) and not 7);
  { generate new backtrace }
  bp:=get_caller_frame(get_frame);
  for i:=1 to tracesize do
   begin
     pp^.calls[i]:=get_caller_addr(bp);
     oldbp:=bp;
     bp:=get_caller_frame(bp);
     if (bp<oldbp) or (bp>(StackBottom + StackLength)) then
       bp:=nil;
   end;
  { regenerate signature }
  if usecrc then
    pp^.sig:=calculate_sig(pp);
  { return the pointer }
  p:=pointer(pp)+sizeof(theap_mem_info);
  TraceReAllocmem:=p;
end;



{*****************************************************************************
                              Check pointer
*****************************************************************************}

{$ifndef Unix}
  {$S-}
{$endif}

{$ifdef go32v2}
var
   __stklen : longword;external name '__stklen';
   __stkbottom : longword;external name '__stkbottom';
   edata : longword; external name 'edata';
{$endif go32v2}

{$ifdef linux}
var
   etext: ptruint; external name '_etext';
   eend : ptruint; external name '_end';
{$endif}

{$ifdef os2}
(* Currently still EMX based - possibly to be changed in the future. *)
var
   etext: ptruint; external name '_etext';
   edata : ptruint; external name '_edata';
   eend : ptruint; external name '_end';
{$endif}

{$ifdef windows}
var
   sdata : ptruint; external name '__data_start__';
   edata : ptruint; external name '__data_end__';
   sbss : ptruint; external name '__bss_start__';
   ebss : ptruint; external name '__bss_end__';
{$endif}


procedure CheckPointer(p : pointer); [public, alias : 'FPC_CHECKPOINTER'];
var
  i  : ptruint;
  pp : pheap_mem_info;
  loc_info: pheap_info;
{$ifdef go32v2}
  get_ebp,stack_top : longword;
  data_end : longword;
{$endif go32v2}
{$ifdef morphos}
  stack_top: longword;
{$endif morphos}
  ptext : ^text;
label
  _exit;
begin
  if p=nil then
    runerror(204);

  i:=0;
  loc_info:=@heap_info;
  if useownfile then
    ptext:=@ownfile
  else
    ptext:=@stderr;

{$ifdef go32v2}
  if ptruint(p)<$1000 then
    runerror(216);
  asm
     movl %ebp,get_ebp
     leal edata,%eax
     movl %eax,data_end
  end;
  stack_top:=__stkbottom+__stklen;
  { allow all between start of code and end of data }
  if ptruint(p)<=data_end then
    goto _exit;
  { stack can be above heap !! }

  if (ptruint(p)>=get_ebp) and (ptruint(p)<=stack_top) then
    goto _exit;
{$endif go32v2}

  { I don't know where the stack is in other OS !! }
{$ifdef windows}
  { inside stack ? }
  if (ptruint(p)>ptruint(get_frame)) and
     (p<StackTop) then
    goto _exit;
  { inside data ? }
  if (ptruint(p)>=ptruint(@sdata)) and (ptruint(p)<ptruint(@edata)) then
    goto _exit;

  { inside bss ? }
  if (ptruint(p)>=ptruint(@sbss)) and (ptruint(p)<ptruint(@ebss)) then
    goto _exit;
{$endif windows}

{$IFDEF OS2}
  { inside stack ? }
  if (PtrUInt (P) > PtrUInt (Get_Frame)) and
     (PtrUInt (P) < PtrUInt (StackTop)) then
    goto _exit;
  { inside data or bss ? }
  if (PtrUInt (P) >= PtrUInt (@etext)) and (PtrUInt (P) < PtrUInt (@eend)) then
    goto _exit;
{$ENDIF OS2}

{$ifdef linux}
  { inside stack ? }
  if (ptruint(p)>ptruint(get_frame)) and
     (ptruint(p)<$c0000000) then      //todo: 64bit!
    goto _exit;
  { inside data or bss ? }
  if (ptruint(p)>=ptruint(@etext)) and (ptruint(p)<ptruint(@eend)) then
    goto _exit;
{$endif linux}

{$ifdef morphos}
  { inside stack ? }
  stack_top:=ptruint(StackBottom)+StackLength;
  if (ptruint(p)<stack_top) and (ptruint(p)>ptruint(StackBottom)) then
    goto _exit;
  { inside data or bss ? }
  {$WARNING data and bss checking missing }
{$endif morphos}

  {$ifdef darwin}
  {$warning No checkpointer support yet for Darwin}
  exit;
  {$endif}

  { first try valid list faster }

{$ifdef EXTRA}
  pp:=loc_info^.heap_valid_last;
  while pp<>nil do
   begin
     { inside this valid block ! }
     { we can be changing the extrainfo !! }
     if (ptruint(p)>=ptruint(pp)+sizeof(theap_mem_info){+extra_info_size}) and
        (ptruint(p)<=ptruint(pp)+sizeof(theap_mem_info)+extra_info_size+pp^.size) then
       begin
          { check allocated block }
          if ((pp^.sig=$DEADBEEF) and not usecrc) or
             ((pp^.sig=calculate_sig(pp)) and usecrc) or
          { special case of the fill_extra_info call }
             ((pp=loc_info^.heap_valid_last) and usecrc and (pp^.sig=$DEADBEEF)
              and loc_info^.inside_trace_getmem) then
            goto _exit
          else
            begin
              writeln(ptext^,'corrupted heap_mem_info');
              dump_error(pp,ptext^);
              halt(1);
            end;
       end
     else
       pp:=pp^.prev_valid;
     inc(i);
     if i>loc_info^.getmem_cnt-loc_info^.freemem_cnt then
      begin
         writeln(ptext^,'error in linked list of heap_mem_info');
         halt(1);
      end;
   end;
  i:=0;
{$endif EXTRA}
  pp:=loc_info^.heap_mem_root;
  while pp<>nil do
   begin
     { inside this block ! }
     if (ptruint(p)>=ptruint(pp)+sizeof(theap_mem_info)+ptruint(extra_info_size)) and
        (ptruint(p)<=ptruint(pp)+sizeof(theap_mem_info)+ptruint(extra_info_size)+ptruint(pp^.size)) then
        { allocated block }
       if ((pp^.sig=$DEADBEEF) and not usecrc) or
          ((pp^.sig=calculate_sig(pp)) and usecrc) then
          goto _exit
       else
         begin
            writeln(ptext^,'pointer $',hexstr(p),' points into invalid memory block');
            dump_error(pp,ptext^);
            runerror(204);
         end;
     pp:=pp^.previous;
     inc(i);
     if i>loc_info^.getmem_cnt then
      begin
         writeln(ptext^,'error in linked list of heap_mem_info');
         halt(1);
      end;
   end;
  writeln(ptext^,'pointer $',hexstr(p),' does not point to valid memory block');
  dump_error(p,ptext^);
  runerror(204);
_exit:
end;

{*****************************************************************************
                              Dump Heap
*****************************************************************************}

procedure dumpheap;
var
  pp : pheap_mem_info;
  i : ptrint;
  ExpectedHeapFree : ptruint;
  status : TFPCHeapStatus;
  ptext : ^text;
  loc_info: pheap_info;
begin
  loc_info:=@heap_info;
  if useownfile then
    ptext:=@ownfile
  else
    ptext:=@stderr;
  pp:=loc_info^.heap_mem_root;
  Writeln(ptext^,'Heap dump by heaptrc unit');
  Writeln(ptext^,loc_info^.getmem_cnt, ' memory blocks allocated : ',
    loc_info^.getmem_size,'/',loc_info^.getmem8_size);
  Writeln(ptext^,loc_info^.freemem_cnt,' memory blocks freed     : ',
    loc_info^.freemem_size,'/',loc_info^.freemem8_size);
  Writeln(ptext^,loc_info^.getmem_cnt-loc_info^.freemem_cnt,
    ' unfreed memory blocks : ',loc_info^.getmem_size-loc_info^.freemem_size);
  status:=SysGetFPCHeapStatus;
  Write(ptext^,'True heap size : ',status.CurrHeapSize);
  if EntryMemUsed > 0 then
    Writeln(ptext^,' (',EntryMemUsed,' used in System startup)')
  else
    Writeln(ptext^);
  Writeln(ptext^,'True free heap : ',status.CurrHeapFree);
  ExpectedHeapFree:=status.CurrHeapSize
    -(loc_info^.getmem8_size-loc_info^.freemem8_size)
    -(loc_info^.getmem_cnt-loc_info^.freemem_cnt)*(sizeof(theap_mem_info)+extra_info_size)
    -EntryMemUsed;
  If ExpectedHeapFree<>status.CurrHeapFree then
    Writeln(ptext^,'Should be : ',ExpectedHeapFree);
  i:=loc_info^.getmem_cnt-loc_info^.freemem_cnt;
  while pp<>nil do
   begin
     if i<0 then
       begin
          Writeln(ptext^,'Error in heap memory list');
          Writeln(ptext^,'More memory blocks than expected');
          exit;
       end;
     if ((pp^.sig=$DEADBEEF) and not usecrc) or
        ((pp^.sig=calculate_sig(pp)) and usecrc) then
       begin
          { this one was not released !! }
          if exitcode<>203 then
            call_stack(pp,ptext^);
          dec(i);
       end
     else if pp^.sig<>$AAAAAAAA then
       begin
          dump_error(pp,ptext^);
{$ifdef EXTRA}
          dump_error(pp,error_file);
{$endif EXTRA}
          loc_info^.error_in_heap:=true;
       end
{$ifdef EXTRA}
     else if pp^.release_sig<>calculate_release_sig(pp) then
       begin
          dump_change_after(pp,ptext^);
          dump_change_after(pp,error_file);
          loc_info^.error_in_heap:=true;
       end
{$endif EXTRA}
       ;
     pp:=pp^.previous;
   end;
  if HaltOnNotReleased and (loc_info^.getmem_cnt<>loc_info^.freemem_cnt) then
    exitcode:=203;
end;


{*****************************************************************************
                                AllocMem
*****************************************************************************}

function TraceAllocMem(size:ptruint):Pointer;
begin
  TraceAllocMem:=SysAllocMem(size);
end;


{*****************************************************************************
                            No specific tracing calls
*****************************************************************************}

procedure TraceInitThread;
var
  loc_info: pheap_info;
begin
  loc_info := @heap_info;
{$ifdef EXTRA}
  loc_info^.heap_valid_first := nil;
  loc_info^.heap_valid_last := nil;
{$endif}
  loc_info^.heap_mem_root := nil;
  loc_info^.getmem_cnt := 0;
  loc_info^.freemem_cnt := 0;
  loc_info^.getmem_size := 0;
  loc_info^.freemem_size := 0;
  loc_info^.getmem8_size := 0;
  loc_info^.freemem8_size := 0;
  loc_info^.error_in_heap := false;
  loc_info^.inside_trace_getmem := false;
  EntryMemUsed := SysGetFPCHeapStatus.CurrHeapUsed;
end;

procedure TraceRelocateHeap;
begin
  main_relo_todolist := @heap_info.heap_free_todo;
  initcriticalsection(todo_lock);
end;

procedure move_heap_info(src_info, dst_info: pheap_info);
var
  heap_mem: pheap_mem_info;
begin
  if src_info^.heap_free_todo <> nil then
    finish_heap_free_todo_list(src_info);
  if dst_info^.heap_free_todo <> nil then
    finish_heap_free_todo_list(dst_info);
  heap_mem := src_info^.heap_mem_root;
  if heap_mem <> nil then
  begin
    repeat
      heap_mem^.todolist := @dst_info^.heap_free_todo;
      if heap_mem^.previous = nil then break;
      heap_mem := heap_mem^.previous;
    until false;
    heap_mem^.previous := dst_info^.heap_mem_root;
    if dst_info^.heap_mem_root <> nil then
      dst_info^.heap_mem_root^.next := heap_mem;
    dst_info^.heap_mem_root := src_info^.heap_mem_root;
  end;
  inc(dst_info^.getmem_cnt, src_info^.getmem_cnt);
  inc(dst_info^.getmem_size, src_info^.getmem_size);
  inc(dst_info^.getmem8_size, src_info^.getmem8_size);
  inc(dst_info^.freemem_cnt, src_info^.freemem_cnt);
  inc(dst_info^.freemem_size, src_info^.freemem_size);
  inc(dst_info^.freemem8_size, src_info^.freemem8_size);
  dst_info^.error_in_heap := dst_info^.error_in_heap or src_info^.error_in_heap;
{$ifdef EXTRA}
  if assigned(dst_info^.heap_valid_first) then
    dst_info^.heap_valid_first^.prev_valid := src_info^.heap_valid_last
  else
    dst_info^.heap_valid_last := src_info^.heap_valid_last;
  dst_info^.heap_valid_first := src_info^.heap_valid_first;
{$endif}
end;

procedure TraceExitThread;
var
  loc_info: pheap_info;
begin
  loc_info := @heap_info;
  entercriticalsection(todo_lock);
  move_heap_info(loc_info, @orphaned_info);
  leavecriticalsection(todo_lock);
end;

function TraceGetHeapStatus:THeapStatus;
begin
  TraceGetHeapStatus:=SysGetHeapStatus;
end;

function TraceGetFPCHeapStatus:TFPCHeapStatus;
begin
    TraceGetFPCHeapStatus:=SysGetFPCHeapStatus;
end;


{*****************************************************************************
                             Program Hooks
*****************************************************************************}

Procedure SetHeapTraceOutput(const name : string);
var i : ptruint;
begin
   if useownfile then
     begin
       useownfile:=false;
       close(ownfile);
     end;
   assign(ownfile,name);
{$I-}
   append(ownfile);
   if IOResult<>0 then
     Rewrite(ownfile);
{$I+}
   useownfile:=true;
   for i:=0 to Paramcount do
     write(ownfile,ParamStr(i),' ');
   writeln(ownfile);
end;

procedure SetHeapExtraInfo( size : ptruint;fillproc : tfillextrainfoproc;displayproc : tdisplayextrainfoproc);
begin
  { the total size must stay multiple of 8, also allocate 2 pointers for
    the fill and display procvars }
  exact_info_size:=size + sizeof(theap_extra_info);
  extra_info_size:=(exact_info_size+7) and not 7;
  fill_extra_info_proc:=fillproc;
  display_extra_info_proc:=displayproc;
end;


{*****************************************************************************
                           Install MemoryManager
*****************************************************************************}

const
  TraceManager:TMemoryManager=(
    NeedLock : true;
    Getmem  : @TraceGetMem;
    Freemem : @TraceFreeMem;
    FreememSize : @TraceFreeMemSize;
    AllocMem : @TraceAllocMem;
    ReAllocMem : @TraceReAllocMem;
    MemSize : @TraceMemSize;
    InitThread: @TraceInitThread;
    DoneThread: @TraceExitThread;
    RelocateHeap: @TraceRelocateHeap;
    GetHeapStatus : @TraceGetHeapStatus;
    GetFPCHeapStatus : @TraceGetFPCHeapStatus;
  );

procedure TraceInit;
begin
  MakeCRC32Tbl;
  main_orig_todolist := @heap_info.heap_free_todo;
  main_relo_todolist := nil;
  TraceInitThread;
  SetMemoryManager(TraceManager);
  useownfile:=false;
  if outputstr <> '' then
     SetHeapTraceOutput(outputstr);
{$ifdef EXTRA}
  Assign(error_file,'heap.err');
  Rewrite(error_file);
{$endif EXTRA}
end;

procedure TraceExit;
begin
  { no dump if error
    because this gives long long listings }
  { clear inoutres, in case the program that quit didn't }
  ioresult;
  if (exitcode<>0) and (erroraddr<>nil) then
    begin
       if useownfile then
         begin
           Writeln(ownfile,'No heap dump by heaptrc unit');
           Writeln(ownfile,'Exitcode = ',exitcode);
         end
       else
         begin
           Writeln(stderr,'No heap dump by heaptrc unit');
           Writeln(stderr,'Exitcode = ',exitcode);
         end;
       if useownfile then
         begin
           useownfile:=false;
           close(ownfile);
         end;
       exit;
    end;
  move_heap_info(@orphaned_info, @heap_info);
  dumpheap;
  if heap_info.error_in_heap and (exitcode=0) then
    exitcode:=203;
  if main_relo_todolist <> nil then
    donecriticalsection(todo_lock);
{$ifdef EXTRA}
  Close(error_file);
{$endif EXTRA}
   if useownfile then
     begin
       useownfile:=false;
       close(ownfile);
     end;
end;

{$if defined(win32) or defined(win64)}
   function GetEnvironmentStrings : pchar; stdcall;
     external 'kernel32' name 'GetEnvironmentStringsA';
   function FreeEnvironmentStrings(p : pchar) : longbool; stdcall;
     external 'kernel32' name 'FreeEnvironmentStringsA';
Function  GetEnv(envvar: string): string;
var
   s : string;
   i : ptruint;
   hp,p : pchar;
begin
   getenv:='';
   p:=GetEnvironmentStrings;
   hp:=p;
   while hp^<>#0 do
     begin
        s:=strpas(hp);
        i:=pos('=',s);
        if upcase(copy(s,1,i-1))=upcase(envvar) then
          begin
             getenv:=copy(s,i+1,length(s)-i);
             break;
          end;
        { next string entry}
        hp:=hp+strlen(hp)+1;
     end;
   FreeEnvironmentStrings(p);
end;
{$else defined(win32) or defined(win64)}

{$ifdef wince}
Function GetEnv(P:string):Pchar;
begin
  { WinCE does not have environment strings.
    Add some way to specify heaptrc options? }
  GetEnv:=nil;
end;
{$else wince}

Function GetEnv(P:string):Pchar;
{
  Searches the environment for a string with name p and
  returns a pchar to it's value.
  A pchar is used to accomodate for strings of length > 255
}
var
  ep    : ppchar;
  i     : ptruint;
  found : boolean;
Begin
  p:=p+'=';            {Else HOST will also find HOSTNAME, etc}
  ep:=envp;
  found:=false;
  if ep<>nil then
   begin
     while (not found) and (ep^<>nil) do
      begin
        found:=true;
        for i:=1 to length(p) do
         if p[i]<>ep^[i-1] then
          begin
            found:=false;
            break;
          end;
        if not found then
         inc(ep);
      end;
   end;
  if found then
   getenv:=ep^+length(p)
  else
   getenv:=nil;
end;
{$endif wince}
{$endif win32}

procedure LoadEnvironment;
var
  i,j : ptruint;
  s   : string;
begin
  s:=Getenv('HEAPTRC');
  if pos('keepreleased',s)>0 then
   keepreleased:=true;
  if pos('disabled',s)>0 then
   useheaptrace:=false;
  if pos('nohalt',s)>0 then
   haltonerror:=false;
  if pos('haltonnotreleased',s)>0 then
   HaltOnNotReleased :=true;
  i:=pos('log=',s);
  if i>0 then
   begin
     outputstr:=copy(s,i+4,255);
     j:=pos(' ',outputstr);
     if j=0 then
      j:=length(outputstr)+1;
     delete(outputstr,j,255);
   end;
end;

// additions for codetools
{$DEFINE MC_ImplementationEnd}
{$i memcheck_laz.inc}
{$UNDEF MC_ImplementationEnd}

Initialization
  LoadEnvironment;
  { heaptrc can be disabled from the environment }
  if useheaptrace then
   TraceInit;
  CheckHeapWrtMemCnt('memcheck.pas Initialization');
finalization
  if useheaptrace then
   TraceExit;
end.