[RFC, libstdc++] Implement C++20 P1208R6 - source_location.

[Ed Smith-Rowland via libstdc++]

As an experiment, I took a shot at implementing source_location for 
C++20.?? This was mostly done in experimental but I wanted to try adding 
column information.?? (The experimental version just returned 0).?? I 
added __builtin_COLUMN in analogy to __builtin_LINE.?? The std version is 
also consteval so you get different results in some cases wrt 
experimental. You can diff the two 1.cc test cases in libstdc++ to see 
for yourself.

As Jonathan mentioned on IRC, we probably want a single builtin and we 
want to coordinate the name with clang (__builtin_source_location?).?? 
But this "works" and it might make useful fodder for the next round.

Ed



-------------- next part --------------
gcc/ChangeLog

2019-11-08  Ed Smith-Rowland  <3dw4rd@verizon.net>

	Implement C++20 P1208R6 - source_location.  Implement column with a
	__builtin_COLUMN for both std and experimental.  The std current()
	is consteval.
	* builtins.c (fold_builtin_COLUMN): New function.
	(fold_builtin_0): Use it.
	* builtins.def: Add __builtin_COLUMN.
	* doc/extend.texi: Doc __builtin_COLUMN.
	* testsuite/c-c++-common/builtin_location.c: __builtin_COLUMN() tests.
	* testsuite/c-c++-common/cpp/has-builtin-2.c: __builtin_COLUMN test.


libstdc++-v3/ChangeLog

2019-11-08  Ed Smith-Rowland  <3dw4rd@verizon.net>

	Implement C++20 P1208R6 - source_location.  Implement column with a
	__builtin_COLUMN for both std and experimental.  The std current()
	is consteval.
	* include/experimental/source_location: Call __builtin_COLUMN
	* include/std/source_location: New header.
	* include/std/version: Add <source_location>
	* testsuite/20_util/source_location/1.cc: New test.
	* libstdc++-v3/testsuite/experimental/source_location/1.cc: Test column.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: source_location.patch
Type: text/x-patch
Size: 12897 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20191108/b46210b4/attachment.bin>