https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108900
--- Comment #3 from Libin Dang <libin.dang at gmail dot com> --- For the uploaded test case, `-fdump-internal-locations' gives the following output: ORDINARY MAP: 9 location_t interval: 274912 <= loc < 1342178464 file: header3.h starting at line: 1 column and range bits: 12 column bits: 7 range bits: 5 reason: 0 (LC_ENTER) included from location: 270816 (in ordinary map 8) header3.h: 1|loc:274912|header3 begins |44555555555555 |99000111222233 |47047036036926 |46802468024680 header3.h: 2|loc:279008|header3 begins |99999999999999 |00111222233344 |47036036926925 |02468024680246 ... header3.h:327613|loc:1342173664|header3 begins |33333333334444 |67778889990001 |92692582581481 |68024680246802 header3.h:327614|loc:1342177760|#include "header2.h" |77777778888888888888 |78889990001112223334 |92582581481470470360 |24680246802468024680 However, location 1342173664 (0x4ffff1e0) < LINE_MAP_MAX_LOCATION_WITH_PACKED_RANGES (0x50000000) but location 1342177760 (0x500001e0) > LINE_MAP_MAX_LOCATION_WITH_PACKED_RANGES, therefore these two locations should not in the same line map. In linemap_line_start() of libcpp/line-map.cc, if it does not create new line map (add_map is false), it will return the following new location: r = set->highest_line + (line_delta << map->m_column_and_range_bits); and this location will be included in the last ordinary map, even that location is greater than LINE_MAP_MAX_LOCATION_WITH_PACKED_RANGES and therefore should be in a new line map. The following patch can fix this issue: --- a/libcpp/line-map.cc +++ b/libcpp/line-map.cc @@ -860,7 +860,9 @@ linemap_line_start (line_maps *set, linenum_type to_line, || (highest > LINE_MAP_MAX_LOCATION_WITH_PACKED_RANGES && map->m_range_bits > 0) || (highest > LINE_MAP_MAX_LOCATION_WITH_COLS - && (set->max_column_hint || highest >= LINE_MAP_MAX_LOCATION))) + && (set->max_column_hint || highest >= LINE_MAP_MAX_LOCATION)) + || ((set->highest_line + (line_delta << map->m_column_and_range_bits)) + > LINE_MAP_MAX_LOCATION_WITH_PACKED_RANGES)) add_map = true; else max_column_hint = set->max_column_hint; After applied this change, the `-fdump-internal-locations' options gives the following results: ORDINARY MAP: 9 location_t interval: 274912 <= loc < 1342174176 file: header3.h starting at line: 1 column and range bits: 12 column bits: 7 range bits: 5 reason: 0 (LC_ENTER) included from location: 270816 (in ordinary map 8) header3.h: 1|loc:274912|header3 begins |44555555555555 |99000111222233 |47047036036926 |46802468024680 header3.h: 2|loc:279008|header3 begins |99999999999999 |00111222233344 |47036036926925 |02468024680246 ... header3.h:327613|loc:1342173664|header3 begins |33333333334444 |67778889990001 |92692582581481 |68024680246802 ORDINARY MAP: 10 location_t interval: 1342174176 <= loc < 1342178272 file: header3.h starting at line: 327614 column and range bits: 12 column bits: 7 range bits: 5 reason: 2 (LC_RENAME) included from location: 270816 (in ordinary map 8) header3.h:327614|loc:1342174176|#include "header2.h" |44444444444444444444 |22233344445556667778 |04703603692692582581 |80246802468024680246