Ivory: how to use the ivory-hw package - haskell

Question

I'm experimenting with Ivory (http://ivorylang.org, https://github.com/GaloisInc/ivory) and using the ivory-hw module to manipulate some registers in a microcontroller.
cmain :: Def ('[] :-> ())
cmain = voidProc "main" $ body $ do
setReg regFoo $ do
clearBit foo_bitbar
setBit foo_bitbaz
forever $ return ()
main_module :: Module
main_module = package "main" $ do
incl cmain
main :: IO ()
main = runCompiler [ main_module ] [] (initialOpts {constFold = True,
outDir = Just "out"})
Building and running gives:
$ exe
*** Procedure main
ERROR: [ No location available ]:
Unbound value: 'ivory_hw_io_write_u32'
exe: Sanity-check failed!
Adding the option scErrors = False to runCompiler turns sanity checks off and the code runs to completion generating sources.
However, main.c contains a call to ivory_hw_io_write_u32 but this function is not defined anywhere (perhaps explaining the error). Poking about github, I can find examples that have a file ivory_hw_prim.h.
After some experimentation, I can include this by adding a module for the hw stuff and then adding that as a dependency to my main_module:
hw_module :: Module
hw_module = package "ivory_hw_prim" hw_moduledef
main_module :: Module
main_module = package "main" $ do
depend hw_module
incl cmain
and calling the runCompiler with hw_artifacts added to generate the header:
main = runCompiler [ main_module ] hw_artifacts (initialOpts {scErrors = False,
constFold = True,
outDir = Just "out"})
This adds ivory_hw_prim.h to the collection of files generated and includes the necessary include in main.h.
However, this only works by retaining the scErrors = False option to runCompiler which suggests that I am still not doing this right.
My question is therefore: What is the correct way to use Ivory's HW package?

Answer 1

The solution is to include hw_moduledef in the package:
main_module :: Module
main_module = package "main" $
incl cmain >> hw_moduledef
(The depend function just includes the header.) Including hw_moduledef in the package "main" makes its definitions visible to the sanity-checker.
By the way, the Ivory module system may be improved in the future, so that Ivory computes, at compile time, the dependencies, relieving the programmer from having to make explicit includes.