Re: Size optimization for objects

["Rego, P." <pvrego@gmail.com>]

> On a 32-bit system (i686, Ubuntu) "nm --print-size --size-sort", gives
> me output with a second column that does look like a size, for example:
> 40301408 0000003c T Handle_TMs
> 40301308 0000003c T Slot_Start_ISR
> 4030cd14 0000003c T XM_read_console
> 4030ccd8 0000003c T XM_write_console
> 4030ec60 0000003c T _TOD_Handler_initialization
> 40311d90 0000003c T _Timer_Manager_initialization
> 403106ac 0000003c T _User_extensions_Add_API_set
> 40302dac 0000003c T ecs_Populate_Synchronization_Message
> 40305294 0000003c T efw_Pool_Is_Valid
> 403071b4 0000003c T emb_Max_RT_To_BC_Transfer_Duration
> 4030d83c 00000040 T Clock_driver_support_initialize_hardware
> 403026c4 00000040 T Time_Span_Max
That's the same with me. 

> Running with --numeric-sort instead of --size-sort show that the "size"
> is indeed computed as the difference between the address of the symbol
> and the address of the symbol with the next higher address, as "man nm"
> says.m
> Perhaps you can show a bit more of your nm output? Could give us more
> basis for guessing what the second column might mean, if it is not "size".
Actually, the only point it that, when I add all the second column values, the resulting value is totally different from the real binary size.

Trying a simple example.

  -- bla.adb
  with Ada.Text_IO;
  procedure Bla is
    procedure Write_Something is
    begin
	Ada.Text_IO.Put_Line ("just a test");
    end Write_Something;
  begin
    	Write_Something;
  end Bla;

and building it with gnatmake bla.adb.

If I run 
   nm --print-size --size-sort bla.o

the console returns me

00000000 00000014 r .rdata
00000022 0000001e T __ada_bla
00000000 00000022 t _bla__write_something.0

and the read size of bla.o is 611 bytes. If I add the second values, the total result is 16#44" which is 68 in decimal, which is not 611 bytes.

Also, if I run 
   nm --print-size --size-sort bla.exe > bla.txt

the bla.parse is big, but adding the second column, the result (in Excel I convert it to decimal before adding) is 8.61147E+12 and the real bla.exe size is 1512500 bytes, also very different.