GitLab

It used to take a whole DynFlags, but that meant we had to
create a DynFlags with (panic "No settings") for settings, as
we didn't have any real settings.

Now we just pass the LogAction, which is all that it actually needed.
The default is exported from DynFlags as defaultLogAction.

This patch disables the use of some GHC extensions in
Safe mode and also the use of certain flags. Some
are disabled completely while others are only allowed
on the command line and not in source PRAGMAS.

We also check that Safe imports are indeed importing
a Safe or Trustworthy module.

Stops us having to temporarily have a panic in the DynFlags.
We still need a panic in the DynFlags used for the top-level
error handler, though.

They are no longer right, as we have Haskell' generating new Haskell
standards.

While trying to fix #1666 (-Werror aborts too early) I decided to some
tidyup in GHC/DriverPipeline/HscMain.

 - The GhcMonad overloading is gone from DriverPipeline and HscMain
   now.  GhcMonad is now defined in a module of its own, and only
   used in the top-level GHC layer.  DriverPipeline and HscMain
   use the plain IO monad and take HscEnv as an argument.

 - WarnLogMonad is gone.  printExceptionAndWarnings is now called
   printException (the old name is deprecated).  Session no longer
   contains warnings.

 - HscMain has its own little monad that collects warnings, and also
   plumbs HscEnv around.  The idea here is that warnings are collected
   while we're in HscMain, but on exit from HscMain (any function) we
   check for warnings and either print them (via log_action, so IDEs
   can still override the printing), or turn them into an error if
   -Werror is on.

 - GhcApiCallbacks is gone, along with GHC.loadWithLogger.  Thomas
   Schilling told me he wasn't using these, and I don't see a good
   reason to have them.

 - there's a new pure API to the parser (suggestion from Neil Mitchell):
      parser :: String
             -> DynFlags
             -> FilePath
             -> Either ErrorMessages (WarningMessages, 
                                      Located (HsModule RdrName))

This change allows the client of CmdLineParser a bit more flexibility,
by giving him an arbitrary computation (not just a deprecation
message) for each flag.  

There are several clients, so there are lots of boilerplate changes.

Immediate motivation: if RTS is not profiled, we want to make 
Template Haskell illegal.  That wasn't with the old setup.

We now first collect the option instructions (from the commandline,
from pragmas in source files, etc), and then later flatten them into
the list of enabled options. This will enable us to use different
standards (H98, H2010, etc) as a base upon which to apply the
instructions, when we don't know what the base will be when we start
collecting instructions.

If the command line contains any Haskell source files, then we behave
as if --make had been given.

The meaning of the -c flag has changed (back): -c now selects one-shot
compilation, but stops before linking.  However, to retain backwards
compatibility, -c is still allowed with --make, and means the same as
--make -no-link.  The -no-link flag has been un-deprecated.

-fno-code is now allowed with --make (#3783); the fact that it was
disabled before was largely accidental, it seems.  We also had some
regressions in this area: it seems that -fno-code was causing a .hc
file to be emitted in certain cases.  I've tidied up the code, there
was no need for -fno-code to be a "mode" flag, as far as I can tell.

-fno-code does not emit interface files, nor does it do recompilation
checking, as suggested in #3783.  This would make Haddock emit
interface files, for example, and I'm fairly sure we don't want to do
that.  Compiling with -fno-code is pretty quick anyway, perhaps we can
get away without recompilation checking.

This means -e must be separated from its argument by a space.
It therefore doesn't try to parse "-exclude-module" as
"execute xclude-module".

We weren't printing any warning for a commandline like
    ghc -M Foo.hs -optdep--exclude-module=Bar -fffi
but the last 2 flags are both deprecated.

This prints a combined hash of the ABIs exposed by the modules listed
on the command line.  It will be used by Cabal for generating a
package Id based on the actual ABI of a package.

Also, libdir is now part of the --info output, so this subsumes the old
--print-libdir flag.
The mode parsing was getting rather adhoc, so I've tidied it up a bit
in the process.

part of it.

Part of the GHC API essentially represents a compilation framework.
The difference of a *framework* as opposed to a *library* is that the
overall structure of the functionality is pre-defined but certain
details can be customised via callbacks.  (Also known as the Hollywood
Principle: "Don't call us, we'll call you.")

This patch introduces a per-session data structure that contains all
the callbacks instead of adding lots of small function arguments
whenever we want to give the user more control over certain parts of
the API.  This should also help with future changes: Adding a new
callback doesn't break old code since code that doesn't know about the
new callback will use the (hopefully sane) default implementation.

Overall, however, we should try and keep the number of callbacks small
and well-defined (and provide useful defaults) and use simple library
routines for the rest.

It now uses the standard warning log and error reporting mechanism.

This fixes trac #1348 (ghci --help gave ghc's help), and also tidies
things up a bit. Things would be even tidier if the usage.txt files were
put into a .hs file, so that ShowUsage wouldn't need to be able to find
the libdir.

They should override other mode flags, not conflict with them

$ ghc -c foo.bar
Warning: the following files would be used as linker inputs, but linking is not being done: foo.bar
ghc: no input files
Usage: For basic information, try the `--help' option.

This allows us to avoid a module import loop:
CmdLineParser -> SrcLoc -> Outputable -> StaticFlags -> CmdLineParser

The flag is off by default, but GHCi turns it on (in Main.hs).  For
GHCi it can be overriden on the command-line or using :set.

Installing and bindist creation don't work, but they were already broken.
Only tested validating with one setup.

we'll create it anyway