This patch refines when driver diagnostics are formatted so that
flang-new and flang-new -fc1 behave consistently with clang and
clang -cc1, respectively. This change only applies to driver diagnostics.
Scanning, parsing and semantic diagnostics are separate and not covered here.
NEW BEHAVIOUR
To illustrate the new behaviour, consider the following input file:
! file.f90 program m integer :: i = k end
In the following invocations, "error: Semantic errors in file.f90" _will be_
formatted:
$ flang-new file.f90 error: Semantic errors in file.f90 ./file.f90:2:18: error: Must be a constant value integer :: i = k $ flang-new -fc1 -fcolor-diagnostics file.f90 error: Semantic errors in file.f90 ./file.f90:2:18: error: Must be a constant value integer :: i = k
However, in the following invocations, "error: Semantic errors in file.f90"
_will not be_ formatted:
$ flang-new -fno-color-diagnostics file.f90 error: Semantic errors in file.f90 ./file.f90:2:18: error: Must be a constant value integer :: i = k $ flang-new -fc1 file.f90 error: Semantic errors in file.f90 ./file.f90:2:18: error: Must be a constant value integer :: i = k
Before this change, none of the above would be formatted. Note also that the
default behaviour in flang-new is different to flang-new -fc1 (this is
consistent with Clang).
NOTES ON IMPLEMENTATION
Note that the diagnostic options are parsed in createAndPopulateDiagOpts in
driver.cpp. That's where the driver's DiagnosticEngine options are set. Like
most command-line compiler driver options, these flags are "claimed" in
Flang.cpp (i.e. when creating a frontend driver invocation) by calling
getLastArg rather than in driver.cpp.
In Clang's Options.td, defm color_diagnostics is replaced with two separate
definitions: def fcolor_diagnostics and def fno_color_diagnostics`. That's
because originally color_diagnostics derived from OptInCC1FFlag, which is a
multiclass for opt-in options in CC1. In order to preserve the current
behaviour in clang -cc1 (i.e. to keep -fno-color-diagnostics unavailable in
clang -cc1) and to implement similar behaviour in flang-new -fc1, we can't
re-use OptInCC1FFlag.
Formatting is only available in consoles that support it and will normally mean that
the message is printed in bold + color.
Co-authored-by: Andrzej Warzynski <andrzej.warzynski@arm.com>
This should be controllable by -f{no}-color-diagnostics.