Previously, the program exit was triggered by the destructor.
Unfortunately, C++ doesn't make it precisely clear where the destructor
is run, and Clang doesn't generate reliable debug information for that
to give good backtraces. Among other things, when combining separate
cleanup regions in Clang there may be no single canonical location.
Instead, move the ExitingStream system to use an explicit
low-precedence operator overload to flush the output and exit. This
ensures the stream and other actions are completed first but then
immediately exits the program in a way that has a definitive source
location and produces reliable backtraces.
I've tried to add comments and helpers to make this as clear as possible
given that it is a subtle and surprising issue.
Co-authored-by: Geoff Romer <gromer@google.com>
This is intended to:
- Standardize use of line_num (and highlight where no line_num is available).
- Standardize indications of runtime/compilation errors.
- Make it incrementally easier to write new errors.
Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
Jon Meow
Chandler CarruthandGeoff Romer