// ../../gcc7/gcc/cp/parser.c:766:7: runtime error: member call on null pointer of type 'struct vec' class A { template <typename> void As(); }; template <typename T> class B : A { void f() { A *g ; g ? g->As<T>() : nullptr; } };
Confirmed. Started with r231293: commit 3d27a0fa5bfc6af64855917aa6f644d2386f8300 Author: dmalcolm <dmalcolm@138bc75d-0d04-0410-961f-82ee72b054a4> Date: Fri Dec 4 18:09:54 2015 +0000 C++ FE: expression ranges markus@x4 tmp % UBSAN_OPTIONS=print_stacktrace=1 /var/tmp/gcc_ubsan/usr/local/bin/g++ -c parse.ii ../../gcc/gcc/cp/parser.c:768:7: runtime error: member call on null pointer of type 'struct vec' #0 0xb5dd4f in cp_lexer_previous_token ../../gcc/gcc/cp/parser.c:768 #1 0xb5dd4f in cp_parser_postfix_dot_deref_expression ../../gcc/gcc/cp/parser.c:7451 #2 0xb6b22d in cp_parser_postfix_expression ../../gcc/gcc/cp/parser.c:7047 #3 0xb70da1 in cp_parser_unary_expression ../../gcc/gcc/cp/parser.c:8099 #4 0xb74cf8 in cp_parser_cast_expression ../../gcc/gcc/cp/parser.c:8776 #5 0xb76faa in cp_parser_binary_expression ../../gcc/gcc/cp/parser.c:8877 #6 0xb79d40 in cp_parser_assignment_expression ../../gcc/gcc/cp/parser.c:9164 #7 0xb88fc0 in cp_parser_expression ../../gcc/gcc/cp/parser.c:9333 #8 0xb79f99 in cp_parser_question_colon_clause ../../gcc/gcc/cp/parser.c:9107 #9 0xb79f99 in cp_parser_assignment_expression ../../gcc/gcc/cp/parser.c:9170 #10 0xb88fc0 in cp_parser_expression ../../gcc/gcc/cp/parser.c:9333 #11 0xb9c9b0 in cp_parser_expression_statement ../../gcc/gcc/cp/parser.c:10877 #12 0xb44d29 in cp_parser_statement ../../gcc/gcc/cp/parser.c:10693 #13 0xb497a0 in cp_parser_statement_seq_opt ../../gcc/gcc/cp/parser.c:11019 #14 0xb49aa4 in cp_parser_compound_statement ../../gcc/gcc/cp/parser.c:10973 #15 0xb96988 in cp_parser_function_body ../../gcc/gcc/cp/parser.c:21357 #16 0xb96988 in cp_parser_ctor_initializer_opt_and_function_body ../../gcc/gcc/cp/parser.c:21393 #17 0xbb9fa2 in cp_parser_function_definition_after_declarator ../../gcc/gcc/cp/parser.c:26151 #18 0xbbb144 in cp_parser_late_parsing_for_member ../../gcc/gcc/cp/parser.c:27033 #19 0xb2e24f in cp_parser_class_specifier_1 ../../gcc/gcc/cp/parser.c:22244 #20 0xb34f42 in cp_parser_class_specifier ../../gcc/gcc/cp/parser.c:22270 #21 0xb34f42 in cp_parser_type_specifier ../../gcc/gcc/cp/parser.c:16386 #22 0xb3780c in cp_parser_decl_specifier_seq ../../gcc/gcc/cp/parser.c:13303 #23 0xb38d5a in cp_parser_single_declaration ../../gcc/gcc/cp/parser.c:26521 #24 0xbb78ee in cp_parser_template_declaration_after_parameters ../../gcc/gcc/cp/parser.c:26212 #25 0xbb6b9a in cp_parser_explicit_template_declaration ../../gcc/gcc/cp/parser.c:26448 #26 0xbb6b9a in cp_parser_template_declaration_after_export ../../gcc/gcc/cp/parser.c:26466 #27 0xb3a349 in cp_parser_declaration ../../gcc/gcc/cp/parser.c:12445 #28 0xbec445 in cp_parser_declaration_seq_opt ../../gcc/gcc/cp/parser.c:12364 #29 0xbecfee in cp_parser_translation_unit ../../gcc/gcc/cp/parser.c:4368 #30 0xbecfee in c_parse_file() ../../gcc/gcc/cp/parser.c:38262 #31 0x1101f4b in c_common_parse_file() ../../gcc/gcc/c-family/c-opts.c:1098 #32 0x24f370a in compile_file ../../gcc/gcc/toplev.c:463 #33 0x64bea4 in do_compile ../../gcc/gcc/toplev.c:1983 #34 0x64bea4 in toplev::main(int, char**) ../../gcc/gcc/toplev.c:2117 #35 0x64e4d6 in main ../../gcc/gcc/main.c:39 #36 0x7f2977921310 in __libc_start_main ../csu/libc-start.c:286 #37 0x64e8e9 in _start (/var/tmp/gcc_ubsan/usr/local/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/cc1plus+0x64e8e9)
760 static inline cp_token * 761 cp_lexer_previous_token (cp_lexer *lexer) 762 { 763 cp_token_position tp = cp_lexer_previous_token_position (lexer); 764 765 /* Skip past purged tokens. */ 766 while (tp->purged_p) 767 { 768 gcc_assert (tp != lexer->buffer->address ()); 769 tp--; 770 } 771 772 return cp_lexer_token_at (lexer, tp); 773 }
Can't reproduce on trunk or GCC 6 branch. What options are required?
(In reply to Richard Biener from comment #3) > Can't reproduce on trunk or GCC 6 branch. What options are required? You need to use an -fsanitize=undefined instrumented compiler. No options required.
(gdb) l 763 cp_token_position tp = cp_lexer_previous_token_position (lexer); 764 765 /* Skip past purged tokens. */ 766 while (tp->purged_p) 767 { 768 gcc_assert (tp != lexer->buffer->address ()); 769 tp--; 770 } 771 772 return cp_lexer_token_at (lexer, tp); (gdb) p *lexer $1 = { buffer = 0x0, last_token = 0x7ffff7e0c2f8, next_token = 0x7ffff7e0c298, saved_tokens = { m_vec = 0x92c6b20 }, next = 0x7ffff5f96480, debugging_p = false, in_pragma = false }
So, perhaps: diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index 08f5f9e52ef2..f430af97fdf1 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -765,7 +765,7 @@ cp_lexer_previous_token (cp_lexer *lexer) /* Skip past purged tokens. */ while (tp->purged_p) { - gcc_assert (tp != lexer->buffer->address ()); + gcc_assert (!lexer->buffer || tp != lexer->buffer->address ()); tp--; }
Created attachment 40445 [details] gcc7-pr71182.patch That or use vec_safe_address for a vector that is not always non-NULL. I'll test this version, let Jason choose what he wants.
Author: jakub Date: Wed Jan 4 20:05:14 2017 New Revision: 244070 URL: https://gcc.gnu.org/viewcvs?rev=244070&root=gcc&view=rev Log: PR c++/71182 * parser.c (cp_lexer_previous_token): Use vec_safe_address in the assertion, as lexer->buffer may be NULL. * g++.dg/cpp0x/pr71182.C: New test. Added: trunk/gcc/testsuite/g++.dg/cpp0x/pr71182.C Modified: trunk/gcc/cp/ChangeLog trunk/gcc/cp/parser.c trunk/gcc/testsuite/ChangeLog
Fixed on the trunk so far.
Author: jakub Date: Tue Jan 17 20:30:25 2017 New Revision: 244550 URL: https://gcc.gnu.org/viewcvs?rev=244550&root=gcc&view=rev Log: Backported from mainline 2017-01-04 Jakub Jelinek <jakub@redhat.com> PR c++/71182 * parser.c (cp_lexer_previous_token): Use vec_safe_address in the assertion, as lexer->buffer may be NULL. * g++.dg/cpp0x/pr71182.C: New test. Added: branches/gcc-6-branch/gcc/testsuite/g++.dg/cpp0x/pr71182.C Modified: branches/gcc-6-branch/gcc/cp/ChangeLog branches/gcc-6-branch/gcc/cp/parser.c branches/gcc-6-branch/gcc/testsuite/ChangeLog
Fixed for 6.4+.