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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">Would it make sense to elaborate the Haddock docs to explain stuff here?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;mso-fareast-language:EN-US">Simon<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Glasgow-haskell-users [mailto:glasgow-haskell-users-bounces@haskell.org]
<b>On Behalf Of </b>Carter Schonwald<br>
<b>Sent:</b> 16 December 2014 06:45<br>
<b>To:</b> Brandon Simmons<br>
<b>Cc:</b> glasgow-haskell-users<br>
<b>Subject:</b> Re: Behavior of touch#<o:p></o:p></span></p>
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<a href="https://github.com/ghc/ghc/blob/8c10b67ba049477cc9ed23e61f5bd119e1cefc29/compiler/cmm/CmmMachOp.hs#L556">https://github.com/ghc/ghc/blob/8c10b67ba049477cc9ed23e61f5bd119e1cefc29/compiler/cmm/CmmMachOp.hs#L556</a><o:p></o:p></p>
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and <a href="https://github.com/ghc/ghc/blob/8c10b67ba049477cc9ed23e61f5bd119e1cefc29/compiler/nativeGen/X86/CodeGen.hs#L1731">https://github.com/ghc/ghc/blob/8c10b67ba049477cc9ed23e61f5bd119e1cefc29/compiler/nativeGen/X86/CodeGen.hs#L1731</a><o:p></o:p></p>
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spell it out a bit more<o:p></o:p></p>
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so touch is preserved through the CMM level, and then gets erased when doing final code gen.<o:p></o:p></p>
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Its meant to ensure on heap pointers remain reachable<o:p></o:p></p>
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<o:p> </o:p></p>
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On Tue, Dec 16, 2014 at 1:43 AM, Carter Schonwald <<a href="mailto:carter.schonwald@gmail.com" target="_blank">carter.schonwald@gmail.com</a>> wrote:<o:p></o:p></p>
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the point of touch is to prevent premature GC, it actually gets erased at the CMM level i believe. <o:p></o:p></p>
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That is, it only makes sense to apply touch to lifted types on the heap! <o:p></o:p></p>
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<o:p> </o:p></p>
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On Mon, Dec 15, 2014 at 4:21 PM, Brandon Simmons <<a href="mailto:brandon.m.simmons@gmail.com" target="_blank">brandon.m.simmons@gmail.com</a>> wrote:<o:p></o:p></p>
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The `primitive` package exports a lifted version of the undocumented `touch#`<br>
<br>
<a href="http://hackage.haskell.org/package/ghc-prim-0.3.1.0/docs/GHC-Prim.html" target="_blank">
http://hackage.haskell.org/package/ghc-prim-0.3.1.0/docs/GHC-Prim.html</a><br>
<br>
which has type:<br>
<br>
touch :: PrimMonad m => a -> m ()<br>
<br>
I'd like to know if this works correctly in general, or will it suffer<br>
from the same gotches w/r/t unboxing as with addFinalizer and Weak<br>
references? i.e. must it only be passed an unboxed type?<br>
<br>
Brandon<br>
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<a href="http://www.haskell.org/mailman/listinfo/glasgow-haskell-users" target="_blank">http://www.haskell.org/mailman/listinfo/glasgow-haskell-users</a><o:p></o:p></p>
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