When a reference to a function-like macro begins during the rescanning
of the expansion of another macro but is not completed by the end of
that expansion, it is necessary to abort that rescanning of that
expansion and try again when more tokens can be acquired. (See the new
unclosed-FLM.F90 test case.) All other Fortran preprocessors to which I
have access can handle this situation.
D155499 fixed an issue with implicit continuations. The fixes included a
nested parenthesis check during definition of a macro which is then
carried over in the scanner state.
This leads to the following corner case to fail:
subroutine foo(a, d)
implicit none
integer :: a
integer :: d
! An implicit continuation won't be considered unless
! the definition of "bar" above is removed/commented
call sub(1,
2)
end subroutine foo
The definition of bar is indeed unbalanced but it is not even used in
the code, so it should not impact whether we apply implicit continuation
in the expansion of sub.
This change aims at addressing this issue by removing the balance check
and constraining a bit more when we consider implicit continuations:
only when we see a left parenthesis after a function-like macro, not a
object-like macro. In this case I think it is OK to (unconditionally)
implicitly continue to the next line in search of the corresponding
right parenthesis. This is, to my understanding, similar to what the C
preprocessor would do according to the description in [1].
[1] https://www.spinellis.gr/blog/20060626/
Differential Revision: https://reviews.llvm.org/D157414
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
Extend the SourceFile class to take account of #line directives
when computing source file positions for error messages.
Adjust the output of #line directives to -E output so that they
reflect any #line directives that were in the input.
Differential Revision: https://reviews.llvm.org/D153910
Ticking off a Parser TODO: Preprocessor::Directive()'s Prescanner
argument should be a reference, not a pointer.
Differential Revision: https://reviews.llvm.org/D109094
Avoid spurious and confusing macro replacements from things like
-DPIC on Fortran source files whose suffixes indicate that preprocessing
is not expected.
Add gfortran-like "-cpp" and "-nocpp" flags to f18 to force predefinition
of macros independent of the source file suffix.
Differential Revision: https://reviews.llvm.org/D96464
Hew more closely to the C17 standard; perform macro replacement
of arguments to function-like macros unless they're being stringified
or pasted. Test with a model "assert" macro idiom that exposed
the problem.
Differential Revision: https://reviews.llvm.org/D87650
