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base repository: rubinius/rubinius
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head repository: rubinius/rubinius
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compare: 0c24d0471f2d
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  • 2 commits
  • 5 files changed
  • 1 contributor

Commits on Jul 22, 2016

  1. Define predicates for MemoryHeader.

    @brixen
    brixen committed Jul 22, 2016
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    203a378 View commit details

  2. Fixed 32-bit code assumption. Fixes #3682. 

    When allocating an Array of size 2**29, Rubinius would allocate a Tuple big
enough to hold 2**29 == 536870912 elements. On a 64bit arch, each of these
elements require sizeof(intptr_t) == 8 bytes. A Tuple memory header is 4 *
sizeof(intptr_t) == 32 bytes. So, we have 2**29*8+32 == 4294967328. It's a big
number, but not so big that the 64bit arch can't easily handle it.

Unfortunately, down in the managed memory code, there was an explicit uint32_t
data type. What happens when 4294967328 == 0x100000020 bytes get put into
32bits? 0x100000020 & 0xffffffff == 32. Those 2**29 elements were being
crammed into 32 bytes. Computers may be magic, but even they can only take so
much.
    @brixen
    brixen committed Jul 22, 2016
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    0c24d04 View commit details
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