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| author | Ömer Sinan Ağacan <omeragacan@gmail.com> | 2018-07-04 09:12:01 +0300 |
|---|---|---|
| committer | Ömer Sinan Ağacan <omeragacan@gmail.com> | 2018-07-04 09:12:27 +0300 |
| commit | 15bb4e0b6c08b1f8f5511f04af14242f13833ed1 (patch) | |
| tree | 2e50184512814b19d4c17d1e0f3ab7a14767e2fa /compiler/ghci | |
| parent | 6cb189d1d465d18879b6a4b107fbdce53b2ebf56 (diff) | |
| download | haskell-15bb4e0b6c08b1f8f5511f04af14242f13833ed1.tar.gz | |
Fix nptr field alignment in RtClosureInspect
`extractSubTerms` (which is extracting pointer and non-pointer fields of a
closure) was computing the alignment incorrectly when aligning a 64-bit value
(e.g. a Double) on i386 by aligning it to 64-bits instead of to word size
(32-bits). This is documented in `mkVirtHeapOffsetsWithPadding`:
> Align the start offset (eg, 2-byte value should be 2-byte aligned).
> But not more than to a word.
Fixes #15061
Test Plan:
Validated on both 32-bit and 64-bit. 32-bit fails with various unrelated stat
failures, but no actual test failures.
Reviewers: hvr, bgamari
Reviewed By: bgamari
Subscribers: simonpj, rwbarton, thomie, carter
GHC Trac Issues: #15061
Differential Revision: https://phabricator.haskell.org/D4906
Diffstat (limited to 'compiler/ghci')
| -rw-r--r-- | compiler/ghci/RtClosureInspect.hs | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/compiler/ghci/RtClosureInspect.hs b/compiler/ghci/RtClosureInspect.hs index 81bdb613b5..d540983139 100644 --- a/compiler/ghci/RtClosureInspect.hs +++ b/compiler/ghci/RtClosureInspect.hs @@ -742,11 +742,14 @@ extractSubTerms recurse clos = liftM thdOf3 . go 0 0 dflags <- getDynFlags let word_size = wORD_SIZE dflags size_b = primRepSizeB dflags rep - -- Fields are always aligned. - !aligned_idx = roundUpTo arr_i size_b + -- Align the start offset (eg, 2-byte value should be 2-byte + -- aligned). But not more than to a word. The offset calculation + -- should be the same with the offset calculation in + -- StgCmmLayout.mkVirtHeapOffsetsWithPadding. + !aligned_idx = roundUpTo arr_i (min word_size size_b) !new_arr_i = aligned_idx + size_b ws | size_b < word_size = - [index size_b array aligned_idx word_size] + [index size_b aligned_idx word_size] | otherwise = let (q, r) = size_b `quotRem` word_size in ASSERT( r == 0 ) @@ -761,7 +764,7 @@ extractSubTerms recurse clos = liftM thdOf3 . go 0 0 (error "unboxedTupleTerm: no HValue for unboxed tuple") terms -- Extract a sub-word sized field from a word - index item_size_b array index_b word_size = + index item_size_b index_b word_size = (word .&. (mask `shiftL` moveBytes)) `shiftR` moveBytes where mask :: Word |