34 lines
1.4 KiB
Text
34 lines
1.4 KiB
Text
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@section WebAssembly backend
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The WebAssembly module file format, at present, is a very simple
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object file format with up to 11 numbered sections plus named
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``custom'' sections. At present, there is no standard for relocations
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or symbols, though a @code{"name"} subsection can assign names to
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function indices and local variables.
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As such, it offers no real advantages over ELF, and intermediate ELF
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files can be used to produce WebAssembly modules. The WebAssembly
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backend aims to enable the opposite: reading a WebAssembly module and
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producing an ELF file containing the same information, which can then
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be manipulated and inspected with standard tools.
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When writing WebAssembly modules, the WebAssembly backend attempts to
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determine based on the section name whether to use a numeric section
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id, a named section header, or to include the section verbatim,
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assuming it already contains any necessary header.
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Function names are supported as symbols; local names and WebAssembly
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relocation sections are currently unsupported.
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There are slight differences in the LEB128 integer implementations
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between the WebAssembly specification and the BFD code; these result
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in some malformed WebAssembly modules being treated as valid.
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@menu
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* File layout::
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@end menu
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@node File layout, WebAssembly
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@subsection File layout
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For a description of the WebAssembly file format, see
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@url{https://github.com/WebAssembly/design/blob/master/BinaryEncoding.md}.
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