[PATCH 1/4] Remove some explicit memory management from dwarf2read.c

[Simon Marchi]

On 2020-01-07 5:07 p.m., Tom Tromey wrote:
> I noticed a few spots in dwarf2read.c that could be improved by moving
> to unique_xmalloc_ptr or, in one case, std::vector.
> 
> gdb/ChangeLog
> 2020-01-07  Tom Tromey  <tromey@adacore.com>
> 
> 	* dwarf2read.c (add_partial_symbol): Use unique_xmalloc_ptr.
> 	(dwarf2_compute_name, open_dwo_file): Likewise.
> 	(process_enumeration_scope): Use std::vector.
> 	(guess_partial_die_structure_name): Use unique_xmalloc_ptr.
> 	(partial_die_info::fixup, dwarf2_start_subfile)
> 	(guess_full_die_structure_name, dwarf2_name): Likewise.
> 	(determine_prefix): Update.
> 	(guess_full_die_structure_name): Make return type const.
> 
> Change-Id: I1cb278c608041ef36ef1f77c7e7565c921038d08

Thanks, this LGTM.  I noted some suggestions below.

> diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
> index 63d533a4459..9fd2b7715b1 100644
> --- a/gdb/dwarf2read.c
> +++ b/gdb/dwarf2read.c
> @@ -8954,13 +8954,13 @@ add_partial_symbol (struct partial_die_info *pdi, struct dwarf2_cu *cu)
>    CORE_ADDR addr = 0;
>    const char *actual_name = NULL;
>    CORE_ADDR baseaddr;
> -  char *built_actual_name;
>  
>    baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
>  
> -  built_actual_name = partial_die_full_name (pdi, cu);
> +  gdb::unique_xmalloc_ptr<char> built_actual_name
> +    (partial_die_full_name (pdi, cu));

You could make partial_die_full_name return a gdb::unique_xmalloc_ptr while at
it, since this is the sole user.  This can then stay an assignment:

  gdb::unique_xmalloc_ptr<char> built_actual_name
    = partial_die_full_name (pdi, cu);

> @@ -16566,34 +16555,26 @@ process_enumeration_scope (struct die_info *die, struct dwarf2_cu *cu)
>  		{
>  		  sym = new_symbol (child_die, this_type, cu);
>  
> -		  if ((num_fields % DW_FIELD_ALLOC_CHUNK) == 0)
> -		    {
> -		      fields = (struct field *)
> -			xrealloc (fields,
> -				  (num_fields + DW_FIELD_ALLOC_CHUNK)
> -				  * sizeof (struct field));
> -		    }

You can actually delete DW_FIELD_ALLOC_CHUNK, defined higher in dwarf2read.c.

Simon