#10871: Implement "buildable" interface files which can be directly compiled without source -------------------------------------+------------------------------------- Reporter: ezyang | Owner: ezyang Type: feature request | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.11 Resolution: | Keywords: backpack Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Description changed by ezyang: Old description:
A fat interface file is like a normal hi file, but with extra information so that GHC can *recompile* the associated module without having to parse, rename and typecheck the source code again. The proposed command- line interface is something like (subject to bikeshedding):
{{{ ghc -c A.hs -fno-code -fwrite-buildable-interface # produces a .hi-build file, then ghc -c A.hi-build # completes building, as if ghc -c A.hs had been called }}}
The primary motivation for this is to support partially compiling indefinite packages, which cannot be compiled to object code due to the fact that some of the dependencies haven't been provided yet. However, there are some other cases where this might be useful:
1. Supercompilation requires having the source of all bindings, buildable interfaces can make this information available, even beyond what storing inlinings might provide 2. A buildable interface file can be used to build variants of a source, e.g. profiling and optimization, even "on the fly" by GHC if necessary.
And maybe more we haven't thought of yet.
The primary function you need to implement is a function from `ModIface`/`ModDetails` to `TcGblEnv`, which can then be fed to the desugarer. I'm looking at what things we need to add to `ModIface` to support this.
New description: A fat interface file is like a normal hi file, but with extra information so that GHC can *recompile* the associated module without having to parse, rename and typecheck the source code again. The proposed command-line interface is something like (subject to bikeshedding): {{{ ghc -c A.hs -fno-code -fwrite-buildable-interface # produces a .hi-build file, then ghc -c A.hi-build # completes building, as if ghc -c A.hs had been called }}} The primary motivation for this is to support partially compiling indefinite packages, which cannot be compiled to object code due to the fact that some of the dependencies haven't been provided yet. However, there are some other cases where this might be useful: 1. Supercompilation requires having the source of all bindings, buildable interfaces can make this information available, even beyond what storing inlinings might provide 2. A buildable interface file can be used to build variants of a source, e.g. profiling and optimization, even "on the fly" by GHC if necessary. And maybe more we haven't thought of yet. Note: we DO run the desugarer before we write out the buildable interface (so we are essentially serializing a `ModGuts`, not a `TcGblEnv`). This does mean that you can't rebuild a buildable interface with hpc (that's done during desugaring) but that seems like a small price to pay. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10871#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler