On Mon, Oct 31, 2016 at 10:38:40AM -0400, Jason Merrill wrote: > > The current DWARF 5 wording is: > > "If the variable entry represents the defining declaration for a C++ static > > data > > member of a structure, class or union, the entry has a DW_AT_specification > > attribute, whose value is a reference to the debugging information entry > > representing the declaration of this data member. The referenced entry has > > the tag DW_TAG_member and will be a child of some class, structure or > > union type entry." on page 98 in DWARF5_Public_Review.pdf. > > Yes, this changed in DWARF 3; DWARF 2 didn't specify the tag. I think > this was a mistake. > > > Incidentally, I've filed today a DWARF issue that Appendix A doesn't list > > for DW_TAG_member lots of attributes that are allowed for DW_TAG_variable > > and are useful for static data members. > > Using DW_TAG_variable would address that, too.
After some IRC discussions, following updated patch ensures that even for inline static data members we emit DW_TAG_member in class with DW_AT_declaration and DW_TAG_variable outside of the class with DW_AT_specification pointing to the DW_TAG_member DIE. DW_AT_location and DW_AT_linkage_name appear on the DW_TAG_variable DIE, DW_AT_const_value/DW_AT_const_expr/DW_AT_inline etc. on DW_TAG_member (except for DW_AT_inline like for non-inline static data members). Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2016-11-01 Jakub Jelinek <ja...@redhat.com> * dwarf2out.c (add_name_and_src_coords_attributes): Add NO_LINKAGE_NAME argument, don't call add_linkage_name if it is true. (gen_variable_die): For C++ inline static data members, consider the initial call when old_die is NULL to be declaration and call add_name_and_src_coords_attributes in that case with true as NO_LINKAGE_NAME. Add DW_AT_inline attribute if needed. (gen_member_die): For C++ inline static data members, emit a definition DIE right away in DW_TAG_compile_unit context. cp/ * cp-objcp-common.c (cp_decl_dwarf_attribute): Handle DW_AT_inline. testsuite/ * g++.dg/debug/dwarf2/inline-var-1.C: New test. --- gcc/dwarf2out.c.jj 2016-10-31 22:46:16.932801519 +0100 +++ gcc/dwarf2out.c 2016-11-01 11:51:57.839403234 +0100 @@ -3503,7 +3503,7 @@ static void add_prototyped_attribute (dw static dw_die_ref add_abstract_origin_attribute (dw_die_ref, tree); static void add_pure_or_virtual_attribute (dw_die_ref, tree); static void add_src_coords_attributes (dw_die_ref, tree); -static void add_name_and_src_coords_attributes (dw_die_ref, tree); +static void add_name_and_src_coords_attributes (dw_die_ref, tree, bool = false); static void add_discr_value (dw_die_ref, dw_discr_value *); static void add_discr_list (dw_die_ref, dw_discr_list_ref); static inline dw_discr_list_ref AT_discr_list (dw_attr_node *); @@ -19820,7 +19820,8 @@ add_linkage_name (dw_die_ref die, tree d given decl, but only if it actually has a name. */ static void -add_name_and_src_coords_attributes (dw_die_ref die, tree decl) +add_name_and_src_coords_attributes (dw_die_ref die, tree decl, + bool no_linkage_name) { tree decl_name; @@ -19833,7 +19834,8 @@ add_name_and_src_coords_attributes (dw_d if (! DECL_ARTIFICIAL (decl)) add_src_coords_attributes (die, decl); - add_linkage_name (die, decl); + if (!no_linkage_name) + add_linkage_name (die, decl); } #ifdef VMS_DEBUGGING_INFO @@ -22215,6 +22217,22 @@ gen_variable_die (tree decl, tree origin bool declaration = (DECL_EXTERNAL (decl_or_origin) || class_or_namespace_scope_p (context_die)); bool specialization_p = false; + bool no_linkage_name = false; + + /* While C++ inline static data members have definitions inside of the + class, force the first DIE to be a declaration, then let gen_member_die + reparent it to the class context and call gen_variable_die again + to create the outside of the class DIE for the definition. */ + if (!declaration + && old_die == NULL + && decl + && DECL_CONTEXT (decl) + && TYPE_P (DECL_CONTEXT (decl)) + && lang_hooks.decls.decl_dwarf_attribute (decl, DW_AT_inline) != -1) + { + declaration = true; + no_linkage_name = true; + } ultimate_origin = decl_ultimate_origin (decl_or_origin); if (decl || ultimate_origin) @@ -22402,7 +22420,7 @@ gen_variable_die (tree decl, tree origin } } else - add_name_and_src_coords_attributes (var_die, decl); + add_name_and_src_coords_attributes (var_die, decl, no_linkage_name); if ((origin == NULL && !specialization_p) || (origin != NULL @@ -22465,6 +22483,17 @@ gen_variable_die (tree decl, tree origin && (origin_die == NULL || get_AT (origin_die, DW_AT_const_expr) == NULL) && !specialization_p) add_AT_flag (var_die, DW_AT_const_expr, 1); + + if (!dwarf_strict) + { + int inl = lang_hooks.decls.decl_dwarf_attribute (decl_or_origin, + DW_AT_inline); + if (inl != -1 + && !get_AT (var_die, DW_AT_inline) + && (origin_die == NULL || get_AT (origin_die, DW_AT_inline) == NULL) + && !specialization_p) + add_AT_unsigned (var_die, DW_AT_inline, inl); + } } /* Generate a DIE to represent a named constant. */ @@ -23622,6 +23651,19 @@ gen_member_die (tree type, dw_die_ref co vlr_ctx.variant_part_offset = NULL_TREE; gen_decl_die (member, NULL, &vlr_ctx, context_die); } + + /* For C++ inline static data members emit immediately a DW_TAG_variable + DIE that will refer to that DW_TAG_member through + DW_AT_specification. */ + if (TREE_STATIC (member) + && (lang_hooks.decls.decl_dwarf_attribute (member, DW_AT_inline) + != -1)) + { + int old_extern = DECL_EXTERNAL (member); + DECL_EXTERNAL (member) = 0; + gen_decl_die (member, NULL, NULL, comp_unit_die ()); + DECL_EXTERNAL (member) = old_extern; + } } /* We do not keep type methods in type variants. */ --- gcc/cp/cp-objcp-common.c.jj 2016-10-31 13:28:11.080382933 +0100 +++ gcc/cp/cp-objcp-common.c 2016-11-01 10:25:14.123707815 +0100 @@ -199,6 +199,16 @@ cp_decl_dwarf_attribute (const_tree decl return 1; break; + case DW_AT_inline: + if (VAR_P (decl) && DECL_INLINE_VAR_P (decl)) + { + if (DECL_VAR_DECLARED_INLINE_P (decl)) + return DW_INL_declared_inlined; + else + return DW_INL_inlined; + } + break; + default: break; } --- gcc/testsuite/g++.dg/debug/dwarf2/inline-var-1.C.jj 2016-11-01 10:25:14.123707815 +0100 +++ gcc/testsuite/g++.dg/debug/dwarf2/inline-var-1.C 2016-11-01 11:57:30.044232487 +0100 @@ -0,0 +1,27 @@ +// { dg-do compile } +// { dg-options "-O -std=c++1z -g -dA -gno-strict-dwarf" } +// { dg-require-weak "" } +// { dg-final { scan-assembler-times "0x3\[^\n\r]* DW_AT_inline" 6 } } +// { dg-final { scan-assembler-times "0x1\[^\n\r]* DW_AT_inline" 2 } } +// { dg-final { scan-assembler-times " DW_AT_declaration" 6 } } +// { dg-final { scan-assembler-times " DW_AT_specification" 6 } } +// { dg-final { scan-assembler-times " DW_AT_\[^\n\r]*linkage_name" 7 } } + +inline int a; +struct S +{ + static inline double b = 4.0; + static constexpr int c = 2; + static constexpr inline char d = 3; +} s; +template <int N> +inline int e = N; +int &f = e<2>; +template <int N> +struct T +{ + static inline double g = 4.0; + static constexpr int h = 2; + static inline constexpr char i = 3; +}; +T<5> t; Jakub