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binjibinji
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[spec] Proper binary format for element segments (#82)
The element segment binary format allows for `ref.null` as well as `ref.func`. TODO: text format
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4 files changed

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‎document/core/binary/modules.rst

Lines changed: 10 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -314,6 +314,7 @@ It decodes into an optional :ref:`start function <syntax-start>` that represents
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single: element; segment
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.. _binary-elem:
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.. _binary-elemsec:
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.. _binary-elemexpr:
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Element Section
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~~~~~~~~~~~~~~~
@@ -327,13 +328,14 @@ It decodes into a vector of :ref:`element segments <syntax-elem>` that represent
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\X{seg}^\ast{:}\Bsection_9(\Bvec(\Belem)) &\Rightarrow& \X{seg} \\
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\production{element segment} & \Belem &::=&
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\hex{00}~~e{:}\Bexpr~~y^\ast{:}\Bvec(\Bfuncidx)
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&\Rightarrow& \{ \ETABLE~0, \EOFFSET~e, \EINIT~y^\ast \} \\
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\production{element segment} & \Belem &::=&
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\hex{01}~~y^\ast{:}\Bvec(\Bfuncidx)
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&\Rightarrow& \{ \EINIT~y^\ast \} \\
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\production{element segment} & \Belem &::=&
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&\Rightarrow& \{ \ETABLE~0, \EOFFSET~e, \EINIT~((\REFFUNC~y)~\END)^\ast \} \\ &&|&
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\hex{01}~~e^\ast{:}\Bvec(\Belemexpr)
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&\Rightarrow& \{ \EINIT~e^\ast \} \\ &&|&
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\hex{02}~~x{:}\Btableidx~~e{:}\Bexpr~~y^\ast{:}\Bvec(\Bfuncidx)
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&\Rightarrow& \{ \ETABLE~x, \EOFFSET~e, \EINIT~y^\ast \} \\
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&\Rightarrow& \{ \ETABLE~x, \EOFFSET~e, \EINIT~((\REFFUNC~y)~\END)^\ast \} \\
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\production{elemexpr} & \Belemexpr &::=&
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\hex{D0}~\hex{0B} &\Rightarrow& \REFNULL~\END \\ &&|&
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\hex{D2}~x{:}\Bfuncidx~\hex{0B} &\Rightarrow& (\REFFUNC~x)~\END \\
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\end{array}
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.. note::
@@ -419,11 +421,9 @@ It decodes into a vector of :ref:`data segments <syntax-data>` that represent th
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\X{seg}^\ast{:}\Bsection_{11}(\Bvec(\Bdata)) &\Rightarrow& \X{seg} \\
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\production{data segment} & \Bdata &::=&
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\hex{00}~~e{:}\Bexpr~~b^\ast{:}\Bvec(\Bbyte)
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&\Rightarrow& \{ \DMEM~0, \DOFFSET~e, \DINIT~b^\ast \} \\
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\production{data segment} & \Bdata &::=&
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&\Rightarrow& \{ \DMEM~0, \DOFFSET~e, \DINIT~b^\ast \} \\ &&|&
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\hex{01}~~b^\ast{:}\Bvec(\Bbyte)
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&\Rightarrow& \{ \DINIT~b^\ast \} \\
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\production{data segment} & \Bdata &::=&
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&\Rightarrow& \{ \DINIT~b^\ast \} \\ &&|&
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\hex{02}~~x{:}\Bmemidx~~e{:}\Bexpr~~b^\ast{:}\Bvec(\Bbyte)
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&\Rightarrow& \{ \DMEM~x, \DOFFSET~e, \DINIT~b^\ast \} \\
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\end{array}

‎document/core/syntax/modules.rst

Lines changed: 6 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -247,6 +247,7 @@ starting with the smallest index not referencing a global :ref:`import <syntax-i
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single: table; element
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single: element; segment
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.. _syntax-elem:
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.. _syntax-elemexpr:
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Element Segments
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~~~~~~~~~~~~~~~~
@@ -260,8 +261,11 @@ The |MELEM| component of a module defines a vector of element segments. Each act
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.. math::
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\begin{array}{llll}
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\production{element segment} & \elem &::=&
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\{ \ETABLE~\tableidx, \EOFFSET~\expr, \EINIT~\vec(\funcidx) \} \\&&|&
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\{ \EINIT~\vec(\funcidx) \} \\
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\{ \ETABLE~\tableidx, \EOFFSET~\expr, \EINIT~\vec(\elemexpr) \} \\&&|&
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\{ \EINIT~\vec(\elemexpr) \} \\
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\production{elemexpr} & \elemexpr &::=&
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\REFNULL~\END \\&&|&
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(\REFFUNC~\funcidx)~\END \\
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\end{array}
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The |EOFFSET| is given by a :ref:`constant <valid-constant>` :ref:`expression <syntax-expr>`.

‎document/core/util/macros.def

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Original file line numberDiff line numberDiff line change
@@ -267,6 +267,9 @@
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.. |EOFFSET| mathdef:: \xref{syntax/modules}{syntax-elem}{\K{offset}}
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.. |EINIT| mathdef:: \xref{syntax/modules}{syntax-elem}{\K{init}}
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.. |REFNULL| mathdef:: \xref{syntax/modules}{syntax-elemexpr}{\K{ref.null}}
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.. |REFFUNC| mathdef:: \xref{syntax/modules}{syntax-elemexpr}{\K{ref.func}}
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.. |DMEM| mathdef:: \xref{syntax/modules}{syntax-data}{\K{data}}
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.. |DOFFSET| mathdef:: \xref{syntax/modules}{syntax-data}{\K{offset}}
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.. |DINIT| mathdef:: \xref{syntax/modules}{syntax-data}{\K{init}}
@@ -302,6 +305,7 @@
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.. |importdesc| mathdef:: \xref{syntax/modules}{syntax-importdesc}{\X{importdesc}}
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.. |exportdesc| mathdef:: \xref{syntax/modules}{syntax-exportdesc}{\X{exportdesc}}
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.. |elem| mathdef:: \xref{syntax/modules}{syntax-elem}{\X{elem}}
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.. |elemexpr| mathdef:: \xref{syntax/modules}{syntax-elemexpr}{\X{elemexpr}}
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.. |data| mathdef:: \xref{syntax/modules}{syntax-data}{\X{data}}
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.. |start| mathdef:: \xref{syntax/modules}{syntax-start}{\X{start}}
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@@ -529,6 +533,7 @@
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.. |Bimportdesc| mathdef:: \xref{binary/modules}{binary-importdesc}{\B{importdesc}}
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.. |Bexportdesc| mathdef:: \xref{binary/modules}{binary-exportdesc}{\B{exportdesc}}
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.. |Belem| mathdef:: \xref{binary/modules}{binary-elem}{\B{elem}}
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.. |Belemexpr| mathdef:: \xref{binary/modules}{binary-elemexpr}{\B{elemexpr}}
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.. |Bcode| mathdef:: \xref{binary/modules}{binary-code}{\B{code}}
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.. |Blocal| mathdef:: \xref{binary/modules}{binary-local}{\B{local}}
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.. |Blocals| mathdef:: \xref{binary/modules}{binary-local}{\B{locals}}
@@ -773,6 +778,7 @@
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.. |vdashmem| mathdef:: \xref{valid/modules}{valid-mem}{\vdash}
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.. |vdashglobal| mathdef:: \xref{valid/modules}{valid-global}{\vdash}
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.. |vdashelem| mathdef:: \xref{valid/modules}{valid-elem}{\vdash}
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.. |vdashelemexpr| mathdef:: \xref{valid/modules}{valid-elemexpr}{\vdash}
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.. |vdashdata| mathdef:: \xref{valid/modules}{valid-data}{\vdash}
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.. |vdashstart| mathdef:: \xref{valid/modules}{valid-start}{\vdash}
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.. |vdashexport| mathdef:: \xref{valid/modules}{valid-export}{\vdash}

‎document/core/valid/modules.rst

Lines changed: 37 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -147,7 +147,7 @@ Element Segments
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Element segments :math:`\elem` are classified by :ref:`segment types <syntax-segtype>`.
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:math:`\{ \ETABLE~x, \EOFFSET~\expr, \EINIT~y^\ast \}`
150+
:math:`\{ \ETABLE~x, \EOFFSET~\expr, \EINIT~e^\ast \}`
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......................................................
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* The table :math:`C.\CTABLES[x]` must be defined in the context.
@@ -160,8 +160,9 @@ Element segments :math:`\elem` are classified by :ref:`segment types <syntax-seg
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* The expression :math:`\expr` must be :ref:`constant <valid-constant>`.
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* For each :math:`y_i` in :math:`y^\ast`,
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the function :math:`C.\CFUNCS[y]` must be defined in the context.
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* For each :math:`e_i` in :math:`e^\ast`,
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* The element expression :math:`e_i` must be :ref:`valid <valid-elemexpr>`.
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* Then the element segment is valid with type |SACTIVE|.
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@@ -174,26 +175,51 @@ Element segments :math:`\elem` are classified by :ref:`segment types <syntax-seg
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\qquad
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C \vdashexprconst \expr \const
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\qquad
177-
(C.\CFUNCS[y] = \functype)^\ast
178+
(C \vdashelemexpr e \ok)^\ast
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}{
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C \vdashelem \{ \ETABLE~x, \EOFFSET~\expr, \EINIT~y^\ast \} : \SACTIVE
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C \vdashelem \{ \ETABLE~x, \EOFFSET~\expr, \EINIT~e^\ast \} : \SACTIVE
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}
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:math:`\{ \EINIT~y^\ast \}`
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......................................................
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:math:`\{ \EINIT~e^\ast \}`
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...........................
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186-
* For each :math:`y_i` in :math:`y^\ast`,
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the function :math:`C.\CFUNCS[y]` must be defined in the context.
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* For each :math:`e_i` in :math:`e^\ast`,
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* The element expression :math:`e_i` must be :ref:`valid <valid-elemexpr>`.
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* Then the element segment is valid with type |SPASSIVE|.
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.. math::
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\frac{
194-
(C.\CFUNCS[y] = \functype)^\ast
196+
(C \vdashelemexpr e \ok)^\ast
197+
}{
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C \vdashelem \{ \EINIT~e^\ast \} : \SPASSIVE
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}
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.. _valid-elemexpr:
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:math:`\elemexpr`
205+
.................
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* An element expression must be:
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* either of the form :math:`\REFNULL~\END`,
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* or of the form :math:`(\REFFUNC~x)~\END`, in which case :math:`C.\CFUNCS[x]` must be defined in the context.
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.. math::
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\frac{
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}{
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C \vdashelemexpr \REFNULL~\END \ok
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}
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\qquad
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\frac{
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C.\CFUNCS[x] = \functype
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}{
196-
C \vdashelem \{ \EINIT~y^\ast \} : \SPASSIVE
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C \vdashelemexpr (\REFFUNC~x)~\END \ok
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}
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