compiler: make sure we reject -O + HscInterpreted
authorAustin Seipp <austin@well-typed.com>
Tue, 19 May 2015 06:56:48 +0000 (01:56 -0500)
committerAustin Seipp <austin@well-typed.com>
Tue, 19 May 2015 06:56:48 +0000 (01:56 -0500)
commitb199536be25ea046079587933cc73d0a948a0626
tree3f30861adc3a101adaf163dad97a0dc24e78ad7a
parentb0b11ad93cf8470caed572dc16e5cf91304fa355
compiler: make sure we reject -O + HscInterpreted

When using GHCi, we explicitly reject optimization, because the
compilers optimization passes can introduce unboxed tuples, which the
interpreter is not able to handle. But this goes the other way too: using
GHCi on optimized code may cause the optimizer to float out breakpoints
that the interpreter introduces. This manifests itself in weird ways,
particularly if you as an API client use custom DynFlags to introduce
optimization in combination with HscInterpreted.

It turns out we weren't checking for consistent DynFlag settings when
doing `setSessionDynFlags`, as #10052 showed. While the main driver
handled it in `DynFlags` via `parseDynamicFlags`, we didn't check this
elsewhere.

This does a little refactoring to split out some of the common code, and
immunizes the various `DynFlags` utilities in the `GHC` module from this
particular bug. We should probably be checking other general invariants
too.

This fixes #10052, and adds some notes about the behavior in `GHC` and
`FloatOut`

As a bonus, expose `warningMsg` from `ErrUtils` as a helper since it
didn't exist (somehow).

Signed-off-by: Austin Seipp <austin@well-typed.com>
Reviewed By: edsko

Differential Revision: https://phabricator.haskell.org/D727

GHC Trac Issues: #10052
compiler/main/DynFlags.hs
compiler/main/ErrUtils.hs
compiler/main/GHC.hs
compiler/simplCore/FloatOut.hs
testsuite/.gitignore
testsuite/tests/ghc-api/T10052/Makefile [new file with mode: 0644]
testsuite/tests/ghc-api/T10052/T10052-input.hs [new file with mode: 0644]
testsuite/tests/ghc-api/T10052/T10052.hs [new file with mode: 0644]
testsuite/tests/ghc-api/T10052/T10052.stderr [new file with mode: 0644]
testsuite/tests/ghc-api/T10052/T10052.stdout [new file with mode: 0644]
testsuite/tests/ghc-api/T10052/all.T [new file with mode: 0644]