[Bug c++/80913] New: [8 regression] Infinite loop in cc1plus with stat hack patch

["ro at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80913

            Bug ID: 80913
           Summary: [8 regression] Infinite loop in cc1plus with stat hack
                    patch
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
                CC: nathan at gcc dot gnu.org
  Target Milestone: ---
            Target: i386-pc-solaris2.12, sparc-sun-solaris2.12

Created attachment 41438
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41438&action=edit
preprocessed input

Between 20170528 (r248544) and 20170529 (r248574), mainline bootstrap on both
Solaris/x86 and Solaris/SPARC hangs in stage2 with cc1plus compiling a
configure
test for basename.  The compilation hasn't finished even after 50 minutes while
it should take only seconds, of course.

The problem boils down to

$ cc1plus -fpreprocessed conftest.ii -quiet -mcpu=v9 -o conftest.s

with the attached conftest.ii.

A stacktrace looks like

8620:   /var/gcc/regression/trunk/12-gcc/build/./prev-gcc/cc1plus -quiet -nost
 009b3dc4 edit_distance_traits<char const*>::get_length(char const*) (fb13b388,
0, 0, 0, 0, 0) + c (spellcheck.h:58)
 009b493c best_match<tree_node*, char const*>::consider(char const*) (ffbf8198,
fb13b388, 1371, 5adda8, 1, 80808080) + 10 (spellcheck.h:103)
 009ab638 consider_binding_level(tree_node*, best_match<tree_node*, char
const*>&, cp_binding_level*, bool, lookup_name_fuzzy_kind) (fb1989d8, ffbf8198,
fb0243b8, 0, 2, fb02e660) + 3ac (cp/name-lookup.c:4977)
 009ab7ec lookup_name_fuzzy(tree_node*, lookup_name_fuzzy_kind) (fb1989d8, 2,
5ac138, 1252, 5ad970, ffbf8104) + 160 (cp/name-lookup.c:4997)
 009aaa2c suggest_alternatives_for(unsigned int, tree_node*, bool) (96415e7,
fb1989d8, 1, 5a9a58, 3, 92) + 374 (cp/name-lookup.c:4721)
 009525c0 unqualified_name_lookup_error(tree_node*, unsigned int) (fb1989d8,
96415e7, fb2065d0, 0, ffbf82a4, ffffffff) + 2fc (cp/lex.c:444)
 00952734 unqualified_fn_lookup_error(cp_expr) (ffbf840c, fb1989d8, 96415e7, 0,
0, 0) + f0 (cp/lex.c:501)
 00b1cd08 perform_koenig_lookup(cp_expr, vec<tree_node*, va_gc, vl_embed>*,
int) (ffbf85e4, fb2065d0, 3, 1, 0, ffbf85dc) + 2c8 (cp/semantics.c:2275)
 009cdb98 cp_parser_postfix_expression(cp_parser*, bool, bool, bool, bool,
cp_id_kind*) (fb16b760, 0, 1, 0, 0, ffbf85b4) + 1958 (cp/parser.c:6896)
 009d1b40 cp_parser_unary_expression(cp_parser*, cp_id_kind*, bool, bool, bool)
(fb16b760, 0, 0, 1, 0, ffbf8964) + 10ec (cp/parser.c:8117)
 009d3014 cp_parser_cast_expression(cp_parser*, bool, bool, bool, cp_id_kind*)
(fb16b760, 0, 1, 0, 0, ffbf8964) + 46c (cp/parser.c:8796)
 009d2da8 cp_parser_cast_expression(cp_parser*, bool, bool, bool, cp_id_kind*)
(fb16b760, 0, 0, 0, 0, ffbf8b30) + 200 (cp/parser.c:8757)
 009d3124 cp_parser_binary_expression(cp_parser*, bool, bool, bool,
cp_parser_prec, cp_id_kind*) (fb16b760, 0, 0, 0, ffbf8b0c, ffffffff) + f4
(cp/parser.c:8898)
 009d430c cp_parser_assignment_expression(cp_parser*, cp_id_kind*, bool, bool)
(fb16b760, 0, 0, 0, 0, ffbf8c74) + c0 (cp/parser.c:9186)
 009d487c cp_parser_expression(cp_parser*, cp_id_kind*, bool, bool) (fb16b760,
0, 0, 0, 0, ffbf8cfc) + 6c (cp/parser.c:9353)
 009d8f90 cp_parser_expression_statement(cp_parser*, tree_node*) (fb16b760, 0,
ffbf8dcc, ffbf8d44, b6cad8, ffbf8d44) + 88 (cp/parser.c:10912)
 009d84b0 cp_parser_statement(cp_parser*, tree_node*, bool, bool*,
vec<tree_node*, va_heap, vl_ptr>*) (fb16b760, 0, 1, 0, 0, 12) + 5f4
(cp/parser.c:10728)
 009d9788 cp_parser_statement_seq_opt(cp_parser*, tree_node*) (fb16b760, 0,
5aeb60, 2af6, 5b7628, 20) + 138 (cp/parser.c:11054)
 009d9618 cp_parser_compound_statement(cp_parser*, tree_node*, int, bool)
(fb16b760, 0, 0, 1, 20, 92) + 214 (cp/parser.c:11008)
 009f55dc cp_parser_function_body(cp_parser*, bool) (fb16b760, 0, 53d5, 5b7e20,
20, fb2e5d18) + 44 (cp/parser.c:21447)
 009f58a0 cp_parser_ctor_initializer_opt_and_function_body(cp_parser*, bool)
(fb16b760, 0, 0, 3b34, 5a00e8, fa033158) + 2b4 (cp/parser.c:21483)
 00a028b4 cp_parser_function_definition_after_declarator(cp_parser*, bool)
(fb16b760, 0, 6655, 5b8158, 20, 0) + 298 (cp/parser.c:26291)
 00a025f4
cp_parser_function_definition_from_specifiers_and_declarator(cp_parser*,
cp_decl_specifier_seq*, tree_node*, cp_declarator const*) (fb16b760, ffbf9184,
0, 27033c8, 0, 0) + 220 (cp/parser.c:26203)
 009eef1c cp_parser_init_declarator(cp_parser*, cp_decl_specifier_seq*,
vec<deferred_access_check, va_gc, vl_embed>*, bool, bool, int, bool*,
tree_node**, unsigned int*, tree_node**) (fb16b760, ffbf9184, 0, 1, 0, 0) + 6fc
(cp/parser.c:19168)
 009dea78 cp_parser_simple_declaration(cp_parser*, bool, tree_node**)
(fb16b760, 1, 0, 5b7800, 1f, fb026000) + 610 (cp/parser.c:12808)
 009de450 cp_parser_block_declaration(cp_parser*, bool) (fb16b760, 0, 0,
2703384, 270337f, 1) + 334 (cp/parser.c:12626)
 009de094 cp_parser_declaration(cp_parser*) (fb16b760, 0, 0, 1, 0, fbbc4000) +
6e0 (cp/parser.c:12523)
 009dd99c cp_parser_declaration_seq_opt(cp_parser*) (fb16b760, 0, 0, 0,
206de08, fb660008) + 1e0 (cp/parser.c:12399)
 009c66cc cp_parser_translation_unit(cp_parser*) (fb16b760, 4, 25b8e20, 5e47b0,
61, 25b7c50) + a8 (cp/parser.c:4364)
 00a33b90 c_parse_file() (0, 25b8e20, 0, 74, fbbc4000, 2671298) + ac
(cp/parser.c:38475)
 00c5bb28 c_common_parse_file() (4f, 13d, 8, 80808080, ffbfc011, ffbf9e45) + 44
(c-opts.c:1104)
 0150e1b8 compile_file() (2, 0, 1ba4242b, 7137d, 92205c, 3b9aca00) + 28
(toplev.c:467)
 015120d8 do_compile() (ffbf96a6, 2637840, 2670838, 18, 0, 2638558) + 21c
(toplev.c:2011)
 01512534 toplev::main(int, char**) (ffbf96a6, 26, ffbf970c, 0, 0, 0) + 208
(toplev.c:2145)
 0201ac18 main     (26, ffbf970c, ffbf97a8, 263e864, 0, 0) + 34 (main.c:39)
 0077390c _start   (0, 0, 0, 0, 0, 0) + 5c

Reverting just this patch (r248574) allows the bootstrap to continue into 
stage3:
Stat hack representation
        * name-lookup.c (STAT_HACK_P, STAT_TYPE, STAT_DECL)
        MAYBE_STAT_DECL, MAYBE_STAT_TYPE): New.
        (stat_hack): New.
        (find_namespace_binding): Replace with ...
        (find_namespace_slot): ... this.
        (find_namespace_value): New.
        (name_lookup::search_namespace_only,
        name_lookup::adl_namespace_only): Adjust.
        (update_binding): Add SLOT parameter, adjust.
        (check_local_shadow): Use find_namespace_value.
        (set_local_extern_decl_linkage): Likewise.
        (do_pushdecl): Adjust for namespace slot.
        (push_local_binding): Assert not a namespace binding.
        (check_for_out_of_scope_variable): Use find_namespace_value.
        (set_identifier_type_value_with_scope): Likewise.
        (get_namespace_binding): Likewise.
        (set_namespace_binding): Delete.
        (set_global_binding): Directly update the binding.
        (finish_namespace_using_decl): Likewise.
        (lookup_type_scope_1): Use find_namespace_slot and update.
        (do_push_nested_namespace): Use find_namespace_value.

  Rainer