write a program with file scope var and part of the name is "anon" and
see what class you will get with your change
Sun
On Fri, Apr 20, 2012 at 3:05 PM, Gang Yu <yugang...@gmail.com> wrote:
> On Fri, Apr 20, 2012 at 2:38 PM, Sun Chan <sun.c...@gmail.com> wrote:
>>
>> It is one thing to allow FE to generate temps with special substring.
>> It it another to assume that special substring always mean compiler
>> generated temps. They are not logically equivalent.
>> Sun
>
>
> Maybe I do not make things clear in my last post. Now, I will put more
> details.
>
> The source code in wgen_spin_symbol.cxx
>
> 1569ST*
> 1570Create_ST_For_Tree (gs_t decl_node)
> 1571{
> 1572 TY_IDX ty_idx;
> 1573 ST* st = NULL;
> 1574 char *name;
> 1575 char tempname[32];
> 1595 if (gs_tree_code(decl_node) == GS_RESULT_DECL) {
> 1596 sprintf(tempname, ".result_decl_%d", gs_decl_uid(decl_node));
> 1597 name = tempname;
> 1598 }
> 1599 else if ((gs_tree_code(decl_node) == GS_FUNCTION_DECL ||
> 1600 gs_tree_code(decl_node) == GS_PARM_DECL ||
> 1601 (gs_tree_code(decl_node) == GS_VAR_DECL &&
> 1602 gs_decl_asmreg(decl_node) >= 0)) &&
> 1603 gs_decl_name(decl_node) != 0)
> 1604 name = (char *) gs_identifier_pointer (gs_decl_name (decl_node));
> 1605 else if (gs_decl_assembler_name (decl_node) && gs_decl_name
> (decl_node))
> 1606 name = (char *) gs_identifier_pointer (gs_decl_assembler_name
> (decl_node));
> 1607 else if (gs_decl_name (decl_node))
> 1608 name = (char *) gs_identifier_pointer (gs_decl_name (decl_node));
>
> 1609 else {
> 1610 sprintf(tempname, "anon%d", ++anon_count);
> 1611 name = tempname;
> 1612 }
> ...
>
> when control goes here, we could say the compiler generate temp var in two
> cases. line 1595-1598 and line 1609-1612, i.e, the green part. common part
> "name = tempname" can be used as the indicate.
>
> We just only want to set the temp var to SCLASS_AUTO for those generated in
> "else" part, i.e, 1609-1612, these names contains "anon", without other flag
> to indicate, we just use this name prefix. So, we can have the following
> change:
>
> 1777 if (name != tempname || strncmp(tempname,"anon",4)) { //
> Not a temp var, or temp var for result_decl, no change
> 1778 sclass = SCLASS_FSTATIC;
> 1779 eclass = EXPORT_LOCAL;
> 1780 } else { // Yes, these are temp vars we want to change
> 1781 sclass = SCLASS_AUTO;
> 1782 eclass = EXPORT_LOCAL;
> 1783 }
> 1784 }
> 1785 if (name != tempname || strncmp(tempname,"anon",4))
> 1786 level = GLOBAL_SYMTAB;
> 1787 else
> 1788 level = CURRENT_SYMTAB;
>
> Regards
> Gang
>
>>
>> On Fri, Apr 20, 2012 at 2:01 PM, Gang Yu <yugang...@gmail.com> wrote:
>> > Hi, Gautam
>> >
>> > Thanks for the review.
>> >
>> > You post a good questtion. In my patch, you may note
>> >
>> > + if (name != tempname || strncmp(tempname,"anon",4)) {
>> >
>> > "name != tempname" address your care.
>> >
>> > Walk though the wgen_spin_symbol.cxx:1611, you may note that
>> >
>> > 1609 else {
>> > 1610 sprintf(tempname, "anon%d", ++anon_count);
>> > 1611 name = tempname;
>> > 1612 }
>> > name == tempname indicate that this is FE generated temp var rather
>> > than var
>> > in user program.
>> > Regards
>> > Gang
>> >
>> >
>> > On Fri, Apr 20, 2012 at 1:54 PM, Gautam Chakrabarti
>> > <gautam.c...@yahoo.com>
>> > wrote:
>> >>
>> >> Hi,
>> >>
>> >> Thanks for working on this issue. But this change is not clean. The
>> >> change
>> >> is essentially assuming special semantics based on a variable name.
>> >> What if
>> >> a user variable is named anon?
>> >>
>> >> -Gautam
>> >>
>> >> From: Gang Yu <yugang...@gmail.com>
>> >> To: open64-devel <open64-devel@lists.sourceforge.net>
>> >> Sent: Thursday, April 19, 2012 2:01 AM
>> >> Subject: [Open64-devel] review request for fix bug965[WGEN]
>> >>
>> >> Hi,
>> >>
>> >> Could a gatekeeper please help review the fix for
>> >> bug965?(http://bugs.open64.net/show_bug.cgi?id=965)
>> >>
>> >> This is a code-size issue for open64, i.e, the compiler generate
>> >> garbage
>> >> code although it still make it right.
>> >>
>> >> a cut-down case below:
>> >>
>> >> static inline __attribute__((always_inline)) int
>> >> x86_this_cpu_constant_test_bit(unsigned int nr,
>> >> const unsigned long *addr)
>> >> {
>> >> unsigned long *a = (unsigned long *)addr + nr / 64;
>> >>
>> >> return ((1UL << (nr % 64)) & ({ typeof(*a) pfo_ret__; switch
>> >> (sizeof(*a))
>> >> {
>> >> case 1: asm("mov" "b ""%%""gs"":" "%P" "1"",%0" : "=q" (pfo_ret_\
>> >> _) : "m" (*a)); break; case 2: asm("mov" "w ""%%""gs"":" "%P" "1"",%0"
>> >> :
>> >> "=r"
>> >> (pfo_ret__) : "m" (*a)); break; case 4: asm("mov" "l ""%%""gs""\
>> >> :" "%P" "1"",%0" : "=r" (pfo_ret__) : "m" (*a)); break; case 8:
>> >> asm("mov"
>> >> "q
>> >> ""%%""gs"":" "%P" "1"",%0" : "=r" (pfo_ret__) : "m" (*a)); break\
>> >> ; default: __bad_percpu_size(); } pfo_ret__; })) != 0;
>> >> }
>> >> opencc -c anon.c -keep
>> >> yug@jupiter:~/work/codesize> readelf -s anon.o
>> >>
>> >>
>> >> Symbol table '.symtab' contains 8 entries:
>> >> Num: Value Size Type Bind Vis Ndx Name
>> >> 4: 0000000000000000 8 OBJECT LOCAL DEFAULT 3 anon1
>> >> x86_this_cpu_constant_test_bit is non-called inline keyword function,
>> >> so
>> >> there should generate nothing symbols in this object file, however,
>> >> anon1 appears unexpected.
>> >> Analysis:
>> >>
>> >> When we examine the WGEN code, we found that the code snipper like
>> >> these:
>> >>
>> >> 1569ST*
>> >> 1570Create_ST_For_Tree (gs_t decl_node)
>> >> 1571{
>> >> ...
>> >> 1609 else {
>> >> 1610 sprintf(tempname, "anon%d", ++anon_count);
>> >> 1611 name = tempname;
>> >> 1612 }
>> >> ...
>> >> 1750 if (gs_tree_public (decl_node)) {
>> >> ...
>> >> 1776 else {
>> >> 1777 sclass = SCLASS_FSTATIC;
>> >> 1778 eclass = EXPORT_LOCAL;
>> >> 1779 }
>> >> 1780 level = GLOBAL_SYMTAB;
>> >> 1781 }
>> >>
>> >> this is to say, when current gs_tree is not public, we generate such a
>> >> variable as File-Scope(static) global variable.
>> >> However, anon1 appears as the temporary variable in a computation.
>> >>
>> >> U8U8LDID 0 <2,4,pfo_ret__> T<9,.predef_U8,8>
>> >> U8STID 0 <1,51,anon1> T<9,.predef_U8,8> {line: 1/7}
>> >> U8INTCONST 1 (0x1)
>> >> I4I4LDID 0 <2,1,nr> T<4,.predef_I4,4>
>> >> I4INTCONST 63 (0x3f)
>> >> I4BAND
>> >> U8SHL
>> >> U8U8LDID 0 <1,51,anon1> T<9,.predef_U8,8>
>> >> U8BAND
>> >> U8INTCONST 0 (0x0)
>> >> I4U8NE
>> >> I4RETURN_VAL {line: 0/0}
>> >> and we do find the producer for anon
>> >> 1609 else {
>> >> 1610 sprintf(tempname, "anon%d", ++anon_count);
>> >> 1611 name = tempname;
>> >> 1612 }
>> >> we should make it SCLASS_AUTO in LOCAL_SYMTAB.
>> >>
>> >> Suggested patch:
>> >> osprey/wgen/wgen_spin_symbol.cxx -- ff56fe0..b24a800 100644
>> >> --- a/osprey/wgen/wgen_spin_symbol.cxx
>> >> +++ b/osprey/wgen/wgen_spin_symbol.cxx
>> >> @@ -1774,10 +1774,18 @@ Create_ST_For_Tree (gs_t decl_node)
>> >> eclass = EXPORT_PREEMPTIBLE;
>> >> }
>> >> else {
>> >> + if (name != tempname || strncmp(tempname,"anon",4)) {
>> >> sclass = SCLASS_FSTATIC;
>> >> eclass = EXPORT_LOCAL;
>> >> + } else {
>> >> + sclass = SCLASS_AUTO;
>> >> + eclass = EXPORT_LOCAL;
>> >> + }
>> >> }
>> >> - level = GLOBAL_SYMTAB;
>> >> + if (name != tempname || strncmp(tempname,"anon",4))
>> >> + level = GLOBAL_SYMTAB;
>> >> + else
>> >> + level = CURRENT_SYMTAB;
>> >> }
>> >> else {
>> >> #ifdef KEY
>> >>
>> >> As an example, I show the codesize comparison to gcc generation and the
>> >> source code in the attach, we can see this is really bad for code-size.
>> >> Could a gatekeeper please help a review? thanks in advance.
>> >>
>> >>
>> >> Regards
>> >> Gang
>> >>
>> >>
>> >>
>> >> ------------------------------------------------------------------------------
>> >> For Developers, A Lot Can Happen In A Second.
>> >> Boundary is the first to Know...and Tell You.
>> >> Monitor Your Applications in Ultra-Fine Resolution. Try it FREE!
>> >> http://p.sf.net/sfu/Boundary-d2dvs2
>> >> _______________________________________________
>> >> Open64-devel mailing list
>> >> Open64-devel@lists.sourceforge.net
>> >> https://lists.sourceforge.net/lists/listinfo/open64-devel
>> >>
>> >>
>> >
>> >
>> >
>> > ------------------------------------------------------------------------------
>> > For Developers, A Lot Can Happen In A Second.
>> > Boundary is the first to Know...and Tell You.
>> > Monitor Your Applications in Ultra-Fine Resolution. Try it FREE!
>> > http://p.sf.net/sfu/Boundary-d2dvs2
>> > _______________________________________________
>> > Open64-devel mailing list
>> > Open64-devel@lists.sourceforge.net
>> > https://lists.sourceforge.net/lists/listinfo/open64-devel
>> >
>
>
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