Sun,
Thanks for the input.
'non-callable' should be right called 'non-called', means the function
marked MARK_DELETED(deletable) by function Mark_Deletable_Funcs at
ipa_cg.cxx. Informally, those functions unreachable by the call-graph can
be marked 'DELETABLE' or 'non-called'.
I think you refer IPA means IPA general, you are right. lwinline
(inliner) is multiplexing part of the IPA general. lwinline does *the DFE*
in inline.cxx before perform_inline:
in inline.cxx:
1058BOOL
1059Inliner(char* input_name, char* output_name)
1060{
1188 if (IPA_Enable_DFE) {
1189#ifdef _LIGHTWEIGHT_INLINER
1190 if (!(INLINE_Inlined_Pu_Call_Graph ||
INLINE_Inlined_Pu_Call_Graph2))
1191#endif // _LIGHTWEIGHT_INLINER
1192 {
1193 set_timer();
1194
1195 Total_Prog_Size = Orig_Prog_Weight -
Eliminate_Dead_Func(FALSE);
1196
1197 get_timer(PHASE_DFE);
1198
1199 }
1200 }
1212 Perform_inlining();
My suggested change does not affect IPA, inline_driver.cxx is not IPA part,
and changes in ipa_cg.cxx(bug838), inline.cxx are enclosed
in _LIGHTWEIGHT_INLINER.
The suggested patch does not affect the inline behaviour, control should
not go real inline performed, for those functions inlined then deleted, the
control should never go there.
This patch definitely should be updated, but I post out to see comments on
the idea. the mentioned DFE and real inline should be departured.
Regards
Gang
On Mon, Nov 21, 2011 at 7:50 AM, Sun Chan <[email protected]> wrote:
> it's not clear what you meant by 'non-callable". please educate me.
>
> your change probably match the gcc behavior, but it's not clear it will
> actually accomplish what you want as "DFE" behavior. I don't believe
> O0/1/2/3 does no dfe, only IPA does. May be you can show me which part of
> compiler will do DFE besides IPA? Even if dfe is performed, "inlined" does
> not imply the function body can be removed, it's a lot more complicated
> than "inlined"
> Sun
>
> On Sun, Nov 20, 2011 at 7:59 PM, Gang Yu <[email protected]> wrote:
>
>> Hi,
>>
>> could a gatekeeper help a review? any suggestions or comments are
>> highly appreciated.
>>
>> This is an accidentally discovered issue when I review
>> bug597<https://bugs.open64.net/show_bug.cgi?id=597>cases:
>>
>> cat bug921 <https://bugs.open64.net/show_bug.cgi?id=921>.c
>> void static test(void)
>> {
>> asm("wrongthing");
>> }
>> yug@jupiter:~/work/bugs/bug921<https://bugs.open64.net/show_bug.cgi?id=921>>
>> gcc -c bug921 <https://bugs.open64.net/show_bug.cgi?id=921>.c -O2
>> yug@jupiter:~/work/bugs/bug921<https://bugs.open64.net/show_bug.cgi?id=921>>
>> gcc -c bug921 <https://bugs.open64.net/show_bug.cgi?id=921>.c -O3
>> yug@jupiter:~/work/bugs/bug921<https://bugs.open64.net/show_bug.cgi?id=921>>
>> gcc -c bug921 <https://bugs.open64.net/show_bug.cgi?id=921>.c -O1
>> yug@jupiter:~/work/bugs/bug921<https://bugs.open64.net/show_bug.cgi?id=921>>
>> clang -c bug921 <https://bugs.open64.net/show_bug.cgi?id=921>.c -O3
>> yug@jupiter:~/work/bugs/bug921<https://bugs.open64.net/show_bug.cgi?id=921>>
>> clang -c bug921 <https://bugs.open64.net/show_bug.cgi?id=921>.c -O2
>> yug@jupiter:~/work/bugs/bug921<https://bugs.open64.net/show_bug.cgi?id=921>>
>> clang -c bug921 <https://bugs.open64.net/show_bug.cgi?id=921>.c -O1
>> yug@jupiter:~/work/bugs/bug921<https://bugs.open64.net/show_bug.cgi?id=921>>
>> clang -c bug921 <https://bugs.open64.net/show_bug.cgi?id=921>.c -O0
>> yug@jupiter:~/work/bugs/bug921<https://bugs.open64.net/show_bug.cgi?id=921>>
>> opencc -c bug921 <https://bugs.open64.net/show_bug.cgi?id=921>.c -O3
>> yug@jupiter:~/work/bugs/bug921<https://bugs.open64.net/show_bug.cgi?id=921>>
>> opencc -c bug921 <https://bugs.open64.net/show_bug.cgi?id=921>.c -O2
>> /tmp/ccspin#.Efw754.s: Assembler messages:
>> /tmp/ccspin#.Efw754.s:30: Error: no such instruction: `wrongthing'
>> yug@jupiter:~/work/bugs/bug921<https://bugs.open64.net/show_bug.cgi?id=921>>
>> opencc -c bug921 <https://bugs.open64.net/show_bug.cgi?id=921>.c -O1
>> /tmp/ccspin#.9hLp6w.s: Assembler messages:
>> /tmp/ccspin#.9hLp6w.s:30: Error: no such instruction: `wrongthing'
>> yug@jupiter:~/work/bugs/bug921<https://bugs.open64.net/show_bug.cgi?id=921>>
>> gcc -c bug921 <https://bugs.open64.net/show_bug.cgi?id=921>.c
>> /tmp/cczPHnnc.s: Assembler messages:
>> /tmp/cczPHnnc.s:11: Error: no such instruction: `wrongthing'
>>
>> obviously, opencc does not delete non-callable static functions at O1/O2,
>> while other compilers do, clang even does more.
>>
>> Investigation shows driver launches the inliner according to wgen return
>> value, i.e, if any function with INLINE attribute, inliner comes. At O3
>> phase, gcc marks all static functions a GS_DECL_INLINE flag at spin tree,
>> which makes the inliner always run. However, at O1/O2 level, it does not,
>> so the inliner unfortunately ignored.
>>
>> The lwinliner actually does two things: DFE then inline. The right logic
>> should be:
>> - at O0 phase, if there are non-callable static functions declared with
>> inline attribute, they should be deleted by DFE, no inline. futhur if there
>> are inline arguments, call DFE and inline. Otherwise, silent.
>> - at optimisation phases, if there are functions with inline attributed,
>> do DFE and inline. Otherwise, we should also launch inliner for *DFE only*.
>> At O3, gcc can help us always call inliner, at O1 or O2, we should open
>> inliner ourselves and tell it only do DFE. since inline costs much.
>>
>> The suggested patch below:
>> osprey/driver/phases.c -- 525b7d1..a47394a 100644
>> --- a/osprey/driver/phases.c
>> +++ b/osprey/driver/phases.c
>> @@ -3197,6 +3197,7 @@ run_compiler (int argc, char *argv[])
>> string_list_t *args;
>> boolean inst_info_updated = FALSE;
>> boolean cmd_line_updated = FALSE;
>> + boolean dfe_only = FALSE;
>> buffer_t rii_file_name;
>> buffer_t ii_file_name;
>> @@ -3215,8 +3216,14 @@ run_compiler (int argc, char *argv[])
>> /* special case where the frontend decided that
>> inliner should not be run */
>> if (run_inline == FALSE && // bug 11325
>> - phase_order[i] == P_inline)
>> - continue;
>> + phase_order[i] == P_inline) {
>> + if (olevel == 0)
>> + continue;
>> + else {
>> + dfe_only = TRUE;
>> + run_inline = TRUE;
>> + }
>> + }
>> if (is_matching_phase(get_phase_mask(phase_order[i]),
>> P_any_ld)) {
>> source_kind = S_o;
>> @@ -3236,8 +3243,10 @@ run_compiler (int argc, char *argv[])
>> option_was_seen(O_inline) ||
>> option_was_seen(O_finline) ||
>> option_was_seen(O_finline_functions))) {
>> - prepend_option_seen
>> (add_string_option(O_INLINE_, "none"));
>> + dfe_only = TRUE;
>> }
>> + if (dfe_only)
>> + add_string(args,"-dfe-only");
>> copy_phase_options (args, phase_order[i]);
>> if (!cmd_line_updated &&
>> @@ -3256,6 +3265,9 @@ run_compiler (int argc, char *argv[])
>> if (has_current_errors()) break;
>> run_phase (phase_order[i],
>> get_full_phase_name(phase_order[i]),
>> args);
>> + /* clear dfe-only flag */
>> + dfe_only = FALSE;
>> +
>> /* undefine the environment variable
>> * DEPENDENCIES_OUTPUT after the pre-processor
>> phase -
>> * bug 386.
>> osprey/ipa/inline/inline.cxx -- 7a2e8ad..d90abf7 100644
>> --- a/osprey/ipa/inline/inline.cxx
>> +++ b/osprey/ipa/inline/inline.cxx
>> @@ -177,6 +177,9 @@ SCOPE* Orig_Scope_tab;
>> extern IP_FILE_HDR_TABLE IP_File_header; // array of IP_FILE_HDR, which
>> // holds per file information
>> +#ifdef _LIGHTWEIGHT_INLINER
>> +extern BOOL DFE_Only;
>> +#endif // _LIGHTWEIGHT_INLINER
>> #ifdef _LIGHTWEIGHT_INLINER
>> AUX_PU_TAB Aux_Pu_Table;
>> @@ -1204,7 +1207,10 @@ Inliner(char* input_name, char* output_name)
>> fclose(f);
>> #endif
>> - Perform_inlining();
>> +#ifdef _LIGHTWEIGHT_INLINER
>> + if (!DFE_Only)
>> + Perform_inlining();
>> +#endif
>> #ifdef _LIGHTWEIGHT_INLINER
>> if (INLINE_Inlined_Pu_Call_Graph || INLINE_Inlined_Pu_Call_Graph2) {
>> osprey/ipa/inline/inline_driver.cxx -- c56f5f5..7382653 100644
>> --- a/osprey/ipa/inline/inline_driver.cxx
>> +++ b/osprey/ipa/inline/inline_driver.cxx
>> @@ -97,7 +97,10 @@ BOOL Verbose = FALSE;
>> */
>> SKIPLIST *IPA_Skip_List = NULL; /* List of skip options */
>> -
>> +/* The DFE_only flag to indicate whether call lwinline
>> + * for DFE only.
>> + */
>> +BOOL DFE_Only = FALSE;
>> /* ====================================================================
>> *
>> @@ -211,9 +214,11 @@ Process_Command_Line (INT argc, char **argv)
>> break; /* ignore the -PHASE: option */
>> case 'd': /* accept and ignore the -dsm flags */
>> - if (strncmp (argv[i]+1, "dsm", 3) != 0)
>> - ErrMsg ( EC_Unknown_Flag, argv[i][0], argv[i] );
>> - break;
>> + if (strncmp (argv[i] +1, "dfe-only", 8) == 0)
>> + DFE_Only = TRUE;
>> + else if (strncmp (argv[i]+1, "dsm", 3) != 0)
>> + ErrMsg ( EC_Unknown_Flag, argv[i][0], argv[i] );
>> + break;
>> default: /* What's this? */
>> ErrMsg ( EC_Unknown_Flag, argv[i][0], argv[i] );
>>
>> Regards
>> Gang
>>
>>
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