https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80780
--- Comment #4 from lbjonnes at cisco dot com --- "redi at gcc dot gnu.org" <gcc-bugzi...@gcc.gnu.org> writes: | https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80780 > | Bug ID: 80780 | Summary: Front-end support needed for | experimental::source_location | Product: gcc | Version: 8.0 | Status: UNCONFIRMED | Severity: normal | Priority: P3 | Component: c++ | Assignee: unassigned at gcc dot gnu.org | Reporter: redi at gcc dot gnu.org | Target Milestone: --- > | I've just added a partial implementation of <experimental/source_location> to | trunk (r248110). > | The missing pieces need some FE help. > | 1) because the location info returned by source_location::current() should be | the location of the caller the current implementation uses default arguments: > | struct source_location | { | // 14.1.2, source_location creation | static constexpr source_location | current(const char* __file = __builtin_FILE(), | const char* __func = __builtin_FUNCTION(), | int __line = __builtin_LINE(), | int __col = 0) noexcept btw. adding a __builtin_COLUMN is quite easy, and I had a patch ealier to do just that. I won't send it though since I have now papers in order and the likelyhood of me getting said papers are slim. | { | source_location __loc; | __loc._M_file = __file; | __loc._M_func = __func; | __loc._M_line = __line; | __loc._M_col = __col; | return __loc; | } > | This works OK, but means the signature of the function doesn't match the one in | the TS (which has no parameters). The standard does allow us to add parameters | with default arguments to member functions, but it might be nice if it wasn't | needed. I'm not sure how best to do that. Maybe make the FE recognise | std::experimental::fundamentals_v2::source_location::current() as magic, so | that location info inside the function uses the location of the caller? Maybe | add a new attribute to perform said magic for any inline function? (If | current() is called indirectly, e.g. through a function pointer, the result is | unspecified so the magic doesn't need to work when the function isn't inlined). > | 2) source_location::current().function_name() uses __func__ which is not very | descriptive in C++. It would be nice to have a __builtin_PRETTY_FUNCTION to get | a better function name than __builtin_FUNCTION provides. > | 3) source_location::column().column() always returns zero, because there's no | "__builtin_column" to get a column number, the way __builtin_LINE gives a line | number. > > | I mistakenly though that calling current() in a default member initializer gave | the wrong locations, but it does the right thing (giving the location of the | constructor body that initializes the member).
