The prescanner performs implicit line continuation when it looks
like the parenthesized arguments of a call to a function-like macro
may span multiple lines. In an attempt to work more like a
Fortran-oblivious C preprocessor, the prescanner will act as if
the following lines had been continuations so that the function-like
macro could be invoked.
This still seems like a good idea, but a recent bug report on
LLVM's GitHub issue tracker shows one way in which it could trigger
inadvertently and mess up a program. So this patch makes the
conditions for implicit line continuation much more strict.
First, the leading parenthesis has to have been preceded by an
identifier that's known to be a macro name. (It doesn't have to
be a function-like macro, since it's possible for a keyword-like
macro to expand to the name of a function-like macro.) Second,
no macro definition can ever have had unbalanced parentheses in
its replacement text.
Also cleans up some parenthesis recognition code to fix some
issues found in testing, so that a token with leading or trailing
spaces can still be recognized as a parenthesis or comma.
Fixes https://github.com/llvm/llvm-project/issues/63844.
Differential Revision: https://reviews.llvm.org/D155499
Rename the current -E option to "-E -Xflang -fno-reformat".
Add a new Parsing::EmitPreprocessedSource() routine to convert the
cooked character stream output of the prescanner back to something
more closely resembling output from a traditional preprocessor;
call this new routine when -E appears.
The new -E output is suitable for use as fixed form Fortran source to
compilation by (one hopes) any Fortran compiler. If the original
top-level source file had been free form source, the output will be
suitable for use as free form source as well; otherwise there may be
diagnostics about missing spaces if they were indeed absent in the
original fixed form source.
Unless the -P option appears, #line directives are interspersed
with the output (but be advised, f18 will ignore these if presented
with them in a later compilation).
An effort has been made to preserve original alphabetic character case
and source indentation.
Add -P and -fno-reformat to the new drivers.
Tweak test options to avoid confusion with prior -E output; use
-fno-reformat where needed, but prefer to keep -E, sometimes
in concert with -P, on most, updating expected results accordingly.
Differential Revision: https://reviews.llvm.org/D106727
Update the preprocessor regression tests to use the new driver if the new driver is built (FLANG_BUILD_NEW_DRIVER=On), otherwise the tests will still run using f18.
Summary of changes:
- Introduce %flang to the regression tests, which points to the new driver if it is built or otherwise points to f18
- Update all tests in flang/test/Preprocessing/ to use %flang
Differential Revision: https://reviews.llvm.org/D94805
