[GOOGLE] Fix LIPO resolved node reference fixup

[Teresa Johnson]

On Fri, Oct 24, 2014 at 10:55 AM, Xinliang David Li <davidxl@google.com> wrote:
> When orgin_addr == addr, is there a guarantee that this assert:
>
>  gcc_assert (TREE_OPERAND (op,0) == addr);
>
> is always true?

It should be, that is the assumption of the code that we are trying to
enforce with the assert.

Teresa

>
> 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



-- 
Teresa Johnson | Software Engineer | tejohnson@google.com | 408-460-2413