Now that semantics is working, the standard -fsyntax-only option of
GNU and Clang should be used as the name of the option that causes
f18 to just run the front-end. Support both options in f18, silently
accepting the old option as a synonym for the new one (as
preferred by the code owner), and replace all instances of the
old -fparse-only option with -fsyntax-only throughout the source base.
Differential Revision: https://reviews.llvm.org/D95887
The previous code had handling for cases when too many file descriptors may be
opened; this is not necessary with MemoryBuffer as the file descriptors are
closed after the mapping occurs. MemoryBuffer also internally handles the case
where a file is small and therefore an mmap is bad for performance; such files
are simply copied to memory after being opened.
Many places elsewhere in the code assume that the buffer is not empty, and the
old file opening code handles this by replacing an empty file with a buffer
containing a single newline. That behavior is now kept in the new MemoryBuffer
based code.
Original-commit: flang-compiler/f18@d34df84351
Reviewed-on: https://github.com/flang-compiler/f18/pull/1032