https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78680
--- Comment #5 from David Malcolm <dmalcolm at gcc dot gnu.org> --- Author: dmalcolm Date: Mon Dec 12 17:37:48 2016 New Revision: 243567 URL: https://gcc.gnu.org/viewcvs?rev=243567&root=gcc&view=rev Log: Fix for PR preprocessor/78680 PR preprocessor/78680 identifies a crash when attempting to issue a -Wformat warning, where the format string includes a string token split across multiple physical source lines via backslash-continued lines. The issue is that libcpp is generating bogus range information for such tokens. For example, in: void fn1() { __builtin_printf("\ %ld.\n\ 2\n"); }; the range of the string token is printed as: __builtin_printf("\ ^~ whereas the range ought to be: __builtin_printf("\ ^~ %ld.\n\ ~~~~~~~ 2\n"); }; ~~~~ The root cause is that the line notes expressing the update of the buffer in lex.c aren't yet updated when the end-point of the token is computed 3095 tok_range.m_finish 3096 = linemap_position_for_column (pfile->line_table, 3097 CPP_BUF_COLUMN (buffer, buffer->cur)); so that the physical line is still regarded as that of the start of the token, and, where CPP_BUF_COLUMN uses (BUF)->line_base, line_base is still the location of the first physical line in the and hence the column information is too large (as if it were the offset in the *logical* line). (the printed range is somewhat misleading; the actual buggy range extends beyond the "\ in the line, but within diagnostic-show-locus.c layout::print_annotation_line only prints up to the xbound set by layout::print_source_line and so truncates most of the buggy range). The fix is to ensure that line notes are handled before calculating the end-point of the token range. This leads to the range for the string token being correctly computed, as: __builtin_printf("\ ^~ %ld.\n\ ~~~~~~~ 2\n"); }; ~~~~ and this leads to get_substring_ranges_for_loc failing gracefully, rather than crashing. gcc/testsuite/ChangeLog: PR preprocessor/78680 * gcc.dg/format/pr78680.c: New test case. * gcc.dg/plugin/diagnostic-test-expressions-1.c (test_multiline_token): New function. * gcc.dg/plugin/diagnostic-test-string-literals-1.c (test_backslash_continued_logical_lines): New function. libcpp/ChangeLog: PR preprocessor/78680 * lex.c (_cpp_lex_direct): Ensure line notes are processed before computing the end-point of the token. Added: trunk/gcc/testsuite/gcc.dg/format/pr78680.c Modified: trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c trunk/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-literals-1.c trunk/libcpp/ChangeLog trunk/libcpp/lex.c
