#1843: ghc 6.8.1 broken on Mac OS X Leopard PPC
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Reporter: guest | Owner:
Type: bug | Status: new
Priority: high | Milestone: 6.8.2
Component: Compiler | Version: 6.8.1
Severity: critical | Resolution:
Keywords: | Difficulty: Unknown
Testcase: | Architecture: powerpc
Os: MacOS X |
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Comment (by thorkilnaur):
I have investigated further and now have definite evidence that the
sequence
{{{
lis r,hi16(s+k)
ori r,r,lo16(s+k)
}}}
(where s is a symbol and k is a literate constant) used to bring the value
s+k into register r is sometimes handled errorneously by (the Xcode 3.0
coming with) Mac OS X 10.5 Leopard. In contrast to (the Xcode 2 that comes
with) 10.4 Tiger that doesn't have this problem.
The evidence indicates that the object code is produced correctly by
Leopard (or at least in consistence with the object code produced by
Tiger), but that the linker fails to process the relocation related to
hi16(s+k) correctly, not only producing the confusing "unknown scattered
relocation type 4" message, but also, in fact, generating incorrect code.
Thus explaining the failure to run any amount of code that has been
prepared in this manner.
I intend to report this problem to Apple. In the meantime, there are
fortunately some work-arounds:
1. Use the sequence
{{{
lis r,ha16(s+k)
la r,lo16(s+k)(r)
}}}
suggested by !ChrisKuklewicz above
17. To retain the lis hi16 + ori lo16 combination, use
{{{
t = s+k
lis r,hi16(t)
ori r,r,lo16(t)
}}}
defining a new symbol t to hold the desired value for hi16.
Both of these methods work, as far as I can tell.
Best regards
Thorkil
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1843#comment:22>
GHC <http://www.haskell.org/ghc/>
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