On Wed, Aug 20, 2014 at 4:30 PM, Bill Schmidt
<wschm...@linux.vnet.ibm.com> wrote:
> Ping -- the patch that depends on this one has been approved, but I am
> still waiting for approval on these target-independent bits.
Ok.
Thanks,
Richard.
> Thanks,
> Bill
>
> On Wed, 2014-08-13 at 18:01 -0500, Bill Schmidt wrote:
>> Hi,
>>
>> I want to reuse some of the infrastructure in web.c (and df.h) for a
>> target-specific RTL pass, particularly the union-find stuff. I could
>> just copy it, I suppose, but it seems better to make the struct
>> web_entry into a class so that I can inherit what I need. That's what
>> this patch does.
>>
>> When I talked about this with some other folks, they mentioned that
>> there has been talk of eliminating the web pass altogether, so that
>> might be an argument in favor of just copying the logic. I am happy to
>> do that if that's deemed preferable.
>>
>> I've taken the original struct and made it a base class that only
>> retains the pred field from the original class, along with the
>> union-find code. The reg field is something I don't need, so I've moved
>> that into a subclass that the web code now uses. I've removed the
>> extra_info field, which is not used and no longer makes sense with
>> inheritance available. The rest of the changes are just adjusting to
>> these modifications.
>>
>> I didn't overly "C++ify" anything, to keep the changes as non-invasive
>> as possible.
>>
>> I'll post the PowerPC patch that makes use of the subclassing shortly.
>>
>> Bootstrapped and tested on powerpc64le-unknown-linux-gnu with no
>> regressions. Is this ok for trunk?
>>
>> Thanks,
>> Bill
>>
>>
>> 2014-08-13 Bill Schmidt <wschm...@linux.vnet.ibm.com>
>>
>> * df.h (web_entry_base): Replace existing struct web_entry with a
>> new class web_entry_base with only the predecessor member.
>> (unionfind_root): Remove declaration and move to class member.
>> (unionfind_union): Remove declaration and move to friend
>> function.
>> (union_defs): Remove declaration.
>> * web.c (web_entry_base::unionfind_root): Modify to be member
>> function and adjust accessors.
>> (unionfind_union): Modify to be friend function and adjust
>> accessors.
>> (web_entry): New subclass of web_entry_base containing the reg
>> member.
>> (union_match_dups): Modify for struct -> class changes.
>> (union_defs): Likewise.
>> (entry_register): Likewise.
>> (pass_web::execute): Likewise.
>>
>>
>> Index: gcc/df.h
>> ===================================================================
>> --- gcc/df.h (revision 213923)
>> +++ gcc/df.h (working copy)
>> @@ -1184,20 +1184,22 @@ df_single_use (const df_insn_info *info)
>>
>> /* web */
>>
>> -/* This entry is allocated for each reference in the insn stream. */
>> -struct web_entry
>> +class web_entry_base
>> {
>> - /* Pointer to the parent in the union/find tree. */
>> - struct web_entry *pred;
>> - /* Newly assigned register to the entry. Set only for roots. */
>> - rtx reg;
>> - void* extra_info;
>> + private:
>> + /* Reference to the parent in the union/find tree. */
>> + web_entry_base *pred_pvt;
>> +
>> + public:
>> + /* Accessors. */
>> + web_entry_base *pred () { return pred_pvt; }
>> + void set_pred (web_entry_base *p) { pred_pvt = p; }
>> +
>> + /* Find representative in union-find tree. */
>> + web_entry_base *unionfind_root ();
>> +
>> + /* Union with another set, returning TRUE if they are already unioned. */
>> + friend bool unionfind_union (web_entry_base *first, web_entry_base
>> *second);
>> };
>>
>> -extern struct web_entry *unionfind_root (struct web_entry *);
>> -extern bool unionfind_union (struct web_entry *, struct web_entry *);
>> -extern void union_defs (df_ref, struct web_entry *,
>> - unsigned int *used, struct web_entry *,
>> - bool (*fun) (struct web_entry *, struct web_entry *));
>> -
>> #endif /* GCC_DF_H */
>> Index: gcc/web.c
>> ===================================================================
>> --- gcc/web.c (revision 213923)
>> +++ gcc/web.c (working copy)
>> @@ -53,17 +53,17 @@ along with GCC; see the file COPYING3. If not see
>>
>> /* Find the root of unionfind tree (the representative of set). */
>>
>> -struct web_entry *
>> -unionfind_root (struct web_entry *element)
>> +web_entry_base *
>> +web_entry_base::unionfind_root ()
>> {
>> - struct web_entry *element1 = element, *element2;
>> + web_entry_base *element = this, *element1 = this, *element2;
>>
>> - while (element->pred)
>> - element = element->pred;
>> - while (element1->pred)
>> + while (element->pred ())
>> + element = element->pred ();
>> + while (element1->pred ())
>> {
>> - element2 = element1->pred;
>> - element1->pred = element;
>> + element2 = element1->pred ();
>> + element1->set_pred (element);
>> element1 = element2;
>> }
>> return element;
>> @@ -74,23 +74,32 @@ along with GCC; see the file COPYING3. If not see
>> nothing is done. Otherwise, return false. */
>>
>> bool
>> -unionfind_union (struct web_entry *first, struct web_entry *second)
>> +unionfind_union (web_entry_base *first, web_entry_base *second)
>> {
>> - first = unionfind_root (first);
>> - second = unionfind_root (second);
>> + first = first->unionfind_root ();
>> + second = second->unionfind_root ();
>> if (first == second)
>> return true;
>> - second->pred = first;
>> + second->set_pred (first);
>> return false;
>> }
>>
>> +class web_entry : public web_entry_base
>> +{
>> + private:
>> + rtx reg_pvt;
>> +
>> + public:
>> + rtx reg () { return reg_pvt; }
>> + void set_reg (rtx r) { reg_pvt = r; }
>> +};
>> +
>> /* For INSN, union all defs and uses that are linked by match_dup.
>> FUN is the function that does the union. */
>>
>> static void
>> -union_match_dups (rtx insn, struct web_entry *def_entry,
>> - struct web_entry *use_entry,
>> - bool (*fun) (struct web_entry *, struct web_entry *))
>> +union_match_dups (rtx insn, web_entry *def_entry, web_entry *use_entry,
>> + bool (*fun) (web_entry_base *, web_entry_base *))
>> {
>> struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
>> df_ref use_link = DF_INSN_INFO_USES (insn_info);
>> @@ -169,9 +178,9 @@ static void
>> the values 0 and 1 are reserved for use by entry_register. */
>>
>> void
>> -union_defs (df_ref use, struct web_entry *def_entry,
>> - unsigned int *used, struct web_entry *use_entry,
>> - bool (*fun) (struct web_entry *, struct web_entry *))
>> +union_defs (df_ref use, web_entry *def_entry,
>> + unsigned int *used, web_entry *use_entry,
>> + bool (*fun) (web_entry_base *, web_entry_base *))
>> {
>> struct df_insn_info *insn_info = DF_REF_INSN_INFO (use);
>> struct df_link *link = DF_REF_CHAIN (use);
>> @@ -246,15 +255,15 @@ void
>> /* Find the corresponding register for the given entry. */
>>
>> static rtx
>> -entry_register (struct web_entry *entry, df_ref ref, unsigned int *used)
>> +entry_register (web_entry *entry, df_ref ref, unsigned int *used)
>> {
>> - struct web_entry *root;
>> + web_entry *root;
>> rtx reg, newreg;
>>
>> /* Find the corresponding web and see if it has been visited. */
>> - root = unionfind_root (entry);
>> - if (root->reg)
>> - return root->reg;
>> + root = (web_entry *)entry->unionfind_root ();
>> + if (root->reg ())
>> + return root->reg ();
>>
>> /* We are seeing this web for the first time, do the assignment. */
>> reg = DF_REF_REAL_REG (ref);
>> @@ -278,7 +287,7 @@ static rtx
>> REGNO (newreg));
>> }
>>
>> - root->reg = newreg;
>> + root->set_reg (newreg);
>> return newreg;
>> }
>>
>> @@ -332,8 +341,8 @@ class pass_web : public rtl_opt_pass
>> unsigned int
>> pass_web::execute (function *fun)
>> {
>> - struct web_entry *def_entry;
>> - struct web_entry *use_entry;
>> + web_entry *def_entry;
>> + web_entry *use_entry;
>> unsigned int max = max_reg_num ();
>> unsigned int *used;
>> basic_block bb;
>> @@ -364,9 +373,9 @@ pass_web::execute (function *fun)
>> }
>>
>> /* Record the number of uses and defs at the beginning of the
>> optimization. */
>> - def_entry = XCNEWVEC (struct web_entry, DF_DEFS_TABLE_SIZE ());
>> + def_entry = XCNEWVEC (web_entry, DF_DEFS_TABLE_SIZE ());
>> used = XCNEWVEC (unsigned, max);
>> - use_entry = XCNEWVEC (struct web_entry, uses_num);
>> + use_entry = XCNEWVEC (web_entry, uses_num);
>>
>> /* Produce the web. */
>> FOR_ALL_BB_FN (bb, fun)
>>
>>
>
>
