[PATCH] D37035: Implement __builtin_LINE() et. al. to support source location capture.

[Eric Fiselier via Phabricator via cfe-commits]

EricWF marked 5 inline comments as done.
EricWF added a comment.

In https://reviews.llvm.org/D37035#1116102, @kunitoki wrote:

> Any news on the status of this ? Would be really nice to have it in.


I think this patch is ready to go; but there is more work to be done, as a separate patch, to support `std::source_location` in a better manner as suggested by @rsmith in the inline comments.



================
Comment at: test/SemaCXX/source_location.cpp:10-35
+struct source_location {
+private:
+  unsigned int __m_line = 0;
+  unsigned int __m_col = 0;
+  const char *__m_file = nullptr;
+  const char *__m_func = nullptr;
+public:
----------------
rsmith wrote:
> This seems suboptimal. It would seem better for the compiler to generate a global containing the relevant data and to represent a `source_location` as a pointer to such a value. We should also try to minimize the number of relocations necessary to build a `source_location` object, since such constructions are likely to be extremely common in some codebases. We should also keep in mind that we're likely to want to add fields to `source_location` in future, so designing it in a way that avoids an ABI break for such cases would be preferable.
> 
> How long has GCC supported this?
@rsmith, I agree with your design for `std::source_location`. However, would it be acceptable for now to commit this patch as only the builtins, since we need those for GCC compatibility anyway?

Then the changes for something like `__builtin_source_location()` can be added afterwards?


https://reviews.llvm.org/D37035