#2224: -fhpc inteferes/prevents rewrite rules from firing -------------------------------------+------------------------------------- Reporter: dons | Owner: andy@… Type: bug | Status: new Priority: lowest | Milestone: 7.12.1 Component: Code Coverage | Version: 6.8.2 Resolution: | Keywords: rules, hpc Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Description changed by thomie: Old description:

Use case:

I'm writing tests for rewrite rules, and using HPC to determine if rules were fired (and their code exercised). HPC is quite cool here, since it lets us see which rules fired, without needing to explicitly export functions to test.

However, -fhpc seems to prevent many rules from firing (likely due to ticks getting in the way?)

For example:

{{{ import qualified Data.ByteString.Char8 as C

main = print (C.pack "literal") }}}

When compiled normally, triggers a nice rewrite rule:

{{{ $ ghc -O2 A.hs -ddump-rule-firings A.hs -c Rule fired: unpack Rule fired: Class op show Rule fired: unpack-list Rule fired: ByteString packChars/packAddress Rule fired: unpack Rule fired: Class op show Rule fired: unpack-list Rule fired: ByteString packChars/packAddres }}}

Now with -fhpc:

{{{ $ ghc -O2 A.hs -ddump-rule-firings A.hs -c -fhpc Rule fired: unpack Rule fired: Class op show Rule fired: unpack-list Rule fired: unpack Rule fired: Class op show Rule fired: unpack-list }}}

What's the best way to ensure the same code is exercised with and without -fhpc here? (I'd quite like to get this working, since rewrite rules benefit from testing.)

New description: Use case: I'm writing tests for rewrite rules, and using HPC to determine if rules were fired (and their code exercised). HPC is quite cool here, since it lets us see which rules fired, without needing to explicitly export functions to test. However, -fhpc seems to prevent many rules from firing (likely due to ticks getting in the way?) For example: {{{ import qualified Data.ByteString.Char8 as C main = print (C.pack "literal") }}} When compiled normally, triggers a nice rewrite rule: {{{ $ ghc -O2 A.hs -ddump-rule-firings -c Rule fired: unpack Rule fired: Class op show Rule fired: unpack-list Rule fired: ByteString packChars/packAddress }}} Now with -fhpc: {{{ $ ghc -O2 A.hs -ddump-rule-firings A.hs -c -fhpc Rule fired: unpack Rule fired: Class op show Rule fired: unpack-list }}} What's the best way to ensure the same code is exercised with and without -fhpc here? (I'd quite like to get this working, since rewrite rules benefit from testing.) -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/2224#comment:19 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler