On Tue, Jan 30, 2024 at 4:58 AM H.J. Lu <hjl.to...@gmail.com> wrote:
>
> On Tue, Jan 30, 2024 at 4:51 AM Jakub Jelinek <ja...@redhat.com> wrote:
> >
> > On Mon, Jan 29, 2024 at 06:05:25PM -0800, H.J. Lu wrote:
> > > LRA may call forcce_const_mem on this insn in the function
> > >
> > > (gdb) call debug_tree (func_decl)
> > > <function_decl 0x7ffff2770900 __ct_base
> > > type <method_type 0x7ffff27511f8
> > > type <void_type 0x7ffff7690f18 void type_6 VOID
> > > align:8 warn_if_not_align:0 symtab:0 alias-set -1
> > > canonical-type 0x7ffff7690f18
> > > pointer_to_this <pointer_type 0x7ffff7697000>>
> > > QI
> > > size <integer_cst 0x7ffff768a2b8 constant 8>
> > > unit-size <integer_cst 0x7ffff768a2d0 constant 1>
> > > align:8 warn_if_not_align:0 symtab:0 alias-set -1
> > > canonical-type 0x7ffff27512a0 method basetype <record_type
> > > 0x7ffff264b0a8 function_summary>
> > > arg-types <tree_list 0x7ffff349acd0 value <pointer_type
> > > 0x7ffff26887e0>
> > > chain <tree_list 0x7ffff349ac58 value <pointer_type
> > > 0x7ffff264b2a0>
> > > chain <tree_list 0x7ffff48c0b68
> > > purpose <integer_cst 0x7ffff768a510 constant 0>
> > > value <boolean_type 0x7ffff7690b28 bool>
> > > chain <tree_list 0x7ffff7685d98 value <void_type
> > > 0x7ffff7690f18 void>>>>>
> > > pointer_to_this <pointer_type 0x7ffff258a888>>
> > > addressable asm_written used nothrow public static weak decl_5 QI
> > > /export/gnu/import/git/gitlab/x86-gcc/gcc/symbol-summary.h:268:1
> > > align:16 warn_if_not_align:0 context <record_type 0x7ffff264b0a8
> > > function_summary> initial <block 0x7ffff22c82a0> abstract_origin
> > > <function_decl 0x7ffff2750700 __ct >
> > > result <result_decl 0x7ffff22abd20 D.160175 type <void_type
> > > 0x7ffff7690f18 void>
> > > ignored VOID
> > > /export/gnu/import/git/gitlab/x86-gcc/gcc/symbol-summary.h:269:20
> > > align:8 warn_if_not_align:0 context <function_decl
> > > 0x7ffff2770900 __ct_base >>
> > > full-name "function_summary<T*>::function_summary(symbol_table*,
> > > bool = false) [with T = clone_info]"
> > > template-info <template_info 0x7ffff349ade8
> > > template <template_decl 0x7ffff26fbf80 __ct type <method_type
> > > 0x7ffff2701540>
> > > VOID
> > > /export/gnu/import/git/gitlab/x86-gcc/gcc/symbol-summary.h:268:1
> > > align:1 warn_if_not_align:0 context <record_type
> > > 0x7ffff27010a8 function_summary> result <function_decl 0x7ffff26fcc00
> > > __ct >
> > > parms <tree_list 0x7ffff37bc730 purpose <integer_cst
> > > 0x7ffff768a2d0 1>
> > > value <tree_vec 0x7ffff304ed00 type <template_decl
> > > 0x7ffff2646e00 function_summary>
> > > length:1
> > > elt:0 <tree_list 0x7ffff37bc708 value <type_decl
> > > 0x7ffff26f5c78 T>>>>
> > > full-name "template<class T>
> > > function_summary<T*>::function_summary(symbol_table*, bool)">
> > > args <tree_vec 0x7ffff30767a0 length:1 elt:0 <record_type
> > > 0x7ffff2987930 clone_info>>>
> > > use_template=1
> > > arguments <parm_decl 0x7ffff2773780 this
> > > type <pointer_type 0x7ffff2751348 type <record_type
> > > 0x7ffff264b0a8 function_summary>
> > > readonly sizes-gimplified public unsigned DI
> > > size <integer_cst 0x7ffff768a1c8 constant 64>
> > > unit-size <integer_cst 0x7ffff768a1e0 constant 8>
> > > align:64 warn_if_not_align:0 symtab:0 alias-set -1
> > > canonical-type 0x7ffff2751348>
> > > readonly used unsigned read DI
> > > /export/gnu/import/git/gitlab/x86-gcc/gcc/symbol-summary.h:269:20 size
> > > <integer_cst 0x7ffff768a1c8 64> unit-size <integer_cst 0x7ffff768a1e0
> > > 8>
> > > align:64 warn_if_not_align:0 context <function_decl
> > > 0x7ffff2770900 __ct_base > abstract_origin <parm_decl 0x7ffff274fa00
> > > this>
> > > (reg/f:DI 117 [ this ]) arg-type <pointer_type 0x7ffff2751348>
> > > incoming-rtl (reg:DI 5 di [ this ])
> > > chain <parm_decl 0x7ffff2773800 symtab type <pointer_type
> > > 0x7ffff264b2a0>
> > > used unsigned DI
> > > /export/gnu/import/git/gitlab/x86-gcc/gcc/symbol-summary.h:268:56 size
> > > <integer_cst 0x7ffff768a1c8 64> unit-size <integer_cst 0x7ffff768a1e0
> > > 8>
> > > align:64 warn_if_not_align:0 context <function_decl
> > > 0x7ffff2770900 __ct_base > abstract_origin <parm_decl 0x7ffff22c1b80
> > > symtab>
> > > (reg/v/f:DI 118 [ symtab ]) arg-type <pointer_type
> > > 0x7ffff264b2a0>
> > > incoming-rtl (reg:DI 4 si [ symtab ]) chain <parm_decl
> > > 0x7ffff2773880 ggc>>>
> > > struct-function 0x7ffff22cb228 chain <function_decl 0x7ffff2770800
> > > __ct_comp >>
> > > (gdb)
> > >
> > > in gcc master branch tree:
> > >
> > > (gdb) call debug_rtx (curr_insn)
> > > (insn 14 128 15 2 (set (reg:V2DI 121 [ _21 ])
> > > (vec_concat:V2DI (symbol_ref/i:DI
> > > ("_ZN16function_summaryIP10clone_infoE16symtab_insertionEP11cgraph_nodePv")
> > > [flags 0x3] <function_decl 0x7ffff2750e00 symtab_insertion>)
> > > (symbol_ref/i:DI
> > > ("_ZN16function_summaryIP10clone_infoE14symtab_removalEP11cgraph_nodePv")
> > > [flags 0x3] <function_decl 0x7ffff2750f00 symtab_removal>)))
> > > "/export/gnu/import/git/gitlab/x86-gcc/gcc/symbol-summary.h":36:22
> > > 7521 {vec_concatv2di}
> > > (expr_list:REG_DEAD (reg/f:DI 123)
> > > (expr_list:REG_DEAD (reg/f:DI 122)
> > > (expr_list:REG_EQUIV (vec_concat:V2DI (symbol_ref/i:DI
> > > ("_ZN16function_summaryIP10clone_infoE16symtab_insertionEP11cgraph_nodePv")
> > > [flags 0x3] <function_decl 0x7ffff2750e00 symtab_insertion>)
> > > (symbol_ref/i:DI
> > > ("_ZN16function_summaryIP10clone_infoE14symtab_removalEP11cgraph_nodePv")
> > > [flags 0x3] <function_decl 0x7ffff2750f00 symtab_removal>))
> > > (nil)))))
> > > (gdb)
> > >
> > > The referenced symbol,
> > > function_summary<clone_info*>::symtab_removal(cgraph_node*, void*),
> > > and the referencing function are in different COMDAT groups.
> >
> > And is the referenced symbol non-public? If so, how does that work?
> >
>
> I didn't check if it is public or private. It is OK for public, but not OK
> for private if they are in different comdat groups.
>
In GCC master source, when we force a comdat function symbol,
which may be in the same comdat group or a different comdat group,
into a constant pool, the symbol is always public. GCC never references
a private comdat function symbol in a different comdat group. We
just need to handle private COMDAT function symbol reference in
the same comdat group by calling function_rodata_section.
--
H.J.
