With C++ module header units it becomes important to distinguish
between macros defined in forced headers (& commandline & builtins)
from those defined in the header file being processed. We weren't
making that easy because we treated the builtins and command-line
locations somewhat file-like, with incrementing line numbers, and
showing them as included from line 1 of the main file. This patch does
3 things:
0) extend the idiom that 'line 0' of a file means 'the file as a whole'
1) builtins and command-line macros are shown as-if included from line zero.
2) when emitting preprocessed output we keep resetting the line number
so that re-reading that preprocessed output will get the same set of
locations for the command line etc.
For instance the new c-c++-common/cpp/line-2.c test, now emits
In file included from <command-line>:
./line-2.h:4:2: error: #error wrong
4 | #error wrong
| ^~~~~
line-2.c:3:11: error: macro "bill" passed 1 arguments, but takes just 0
3 | int bill(1);
| ^
In file included from <command-line>:
./line-2.h:3: note: macro "bill" defined here
3 | #define bill() 2
|
Before it told you about including from <command-line>:31.
the preprocessed output looks like:
...
(There's a new optimization in do_line_marker to stop each of these
line markers causing a new line map. We can simply rewind the
location, and keep using the same line map.)
libcpp/
* directives.c (do_linemarker): Optimize rewinding to line zero.
* files.c (_cpp_stack_file): Start on line zero when about to inject
headers.
(cpp_push_include, cpp_push_default_include): Use highest_line as
the location.
* include/cpplib.h (cpp_read_main_file): Add injecting parm.
* init.c (cpp_read_main_file): Likewise, inform _cpp_stack_file.
* internal.h (enum include_type): Add IT_MAIN_INJECT.
gcc/c-family/
* c-opts.c (c_common_post_options): Add 'injecting' arg to
cpp_read_main_file.
(c_finish_options): Add linemap_line_start calls for builtin and cmd
maps. Force token position to line_table's highest line.
* c-ppoutput.c (print_line_1): Refactor, print line zero.
(cb_define): Always increment source line.
gcc/testsuite/
* c-c++-common/cpp/line-2.c: New.
* c-c++-common/cpp/line-2.h: New.
* c-c++-common/cpp/line-3.c: New.
* c-c++-common/cpp/line-4.c: New.
* c-c++-common/cpp/line-4.h: New.
6bf2ff0d52