Re: [GOOGLE] Fix LIPO resolved node reference fixup

[Xinliang David Li <davidxl at google dot com>]

When orgin_addr == addr, is there a guarantee that this assert:

 gcc_assert (TREE_OPERAND (op,0) == addr);

is always true?

David



On Fri, Oct 24, 2014 at 10:21 AM, Teresa Johnson <tejohnson@google.com> wrote:
> This patch makes a fix to the reference fixups performed after LIPO
> node resolution, to better handle the case where we are updating the
> base address of a reference.
>
> Fixes google benchmark and passes regression tests. Ok for google/4_9?
>
> Thanks,
> Teresa
>
> 2014-10-24  Teresa Johnson  <tejohnson@google.com>
>
>         Google ref b/18110567.
>         * cgraphbuild.c (get_base_address_expr): New function.
>         (fixup_ref): Update the op expression for new base address.
>
> Index: cgraphbuild.c
> ===================================================================
> --- cgraphbuild.c       (revision 216667)
> +++ cgraphbuild.c       (working copy)
> @@ -665,13 +665,35 @@ record_references_in_initializer (tree decl, bool
>    pointer_set_destroy (visited_nodes);
>  }
>
> +/* Similar to get_base_address but returns the ADDR_EXPR pointing
> +   to the base address corresponding to T.  */
> +
> +static tree
> +get_base_address_expr (tree t)
> +{
> +  while (handled_component_p (t))
> +    t = TREE_OPERAND (t, 0);
> +
> +  if ((TREE_CODE (t) == MEM_REF
> +       || TREE_CODE (t) == TARGET_MEM_REF)
> +      && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR)
> +    return TREE_OPERAND (t, 0);
> +
> +  return NULL_TREE;
> +}
> +
>  /* Update any function decl references in base ADDR of operand OP to refer to
>     the resolved node.  */
>
>  static bool
>  fixup_ref (gimple, tree addr, tree op)
>  {
> +  tree orig_addr = addr;
>    addr = get_base_address (addr);
> +  /* If the address was changed, update the operand OP to be the
> +     ADDR_EXPR pointing to the new base address.  */
> +  if (orig_addr != addr)
> +    op = get_base_address_expr (orig_addr);
>    if (addr && TREE_CODE (addr) == FUNCTION_DECL)
>      {
>        gcc_assert (TREE_CODE (op) == ADDR_EXPR);
>
>
> --
> Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413