I'm lost. * What causes the undesired behaviour in GHC 8.2.1? Is it this? - GHCi wants to load module B with flags F - There is a B.o but the flags differ - So GHCi recompiles B to bytecode * How does (1) help? * Does (2) propose a new command (:load *M vs :load M)? If so, how does it help. * Is (3), what is the spec of the proposed new flags? Is it this? - GHC wants to compile module B with flags F - There is a B.o compiled with flags F' - And B.hs (and its dependencies) have not changed - Then normally we'd recompile F unless F = F' - But with -fignore-optim-changes we would weaken that equality to ignore differences between F and F' that only affected optimisation level (the list of such flags would need to be written out) - And similarly for -fignore-hpc-changes Precision is all! Thanks Simon | -----Original Message----- | From: ghc-devs [mailto:ghc-devs-bounces@haskell.org] On Behalf Of David | Feuer | Sent: 31 October 2017 15:42 | To: ghc-devs@haskell.org | Subject: GHCi recompilation avoidance UI | | Changes in GHC 8.2.1 lead to a lot of recompilation, because GHCi now | refuses to load optimized code unless -fobject-code (and optimization | flags) are enabled. I propose the following slight modification to | https://ghc.haskell.org/trac/ghc/ticket/13604#comment:48 | | 1. Optimization flags (except -O0) imply -fobject-code. This ensures | that GHC respects optimization flags regardless of --interactive. | | 2. Even when -fobject-code is on, :load *M will load M as bytecode. | This provides the "escape hatch" from -fobject-code that you need to | use debugging features, etc. | | 3. New -fignore-optim-changes and -fignore-hpc-changes (Phab:D4123) | flags should enable users to put together object code and bytecode with | diverse optimization levels/options and HPC options while still | updating automatically based on source changes and whether profiling is | enabled. | | Does this seem like a reasonable way forward? | | David Feuer | _______________________________________________ | ghc-devs mailing list | ghc-devs@haskell.org | https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmail.ha | skell.org%2Fcgi-bin%2Fmailman%2Flistinfo%2Fghc- | devs&data=02%7C01%7Csimonpj%40microsoft.com%7Cd533ac396d6a4a6ff68208d52 | 076040e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636450613629249637 | &sdata=9duvpS1xcNXXUm%2BOJgWg4jFBCgvT3SqPJMU2k8Rdxj0%3D&reserved=0