current core formal spec for the WebAssembly Exception Handling proposal

Following the informal formal spec by Andreas Rossberg :
WebAssembly#87 (comment)
and the discussions in the issues.

Author: ioannad

document/core/appendix/algorithm.rst

@@ -25,13 +25,13 @@ Types are representable as an enumeration.
 
 .. code-block:: pseudo
 
-   type val_type = I32 | I64 | F32 | F64 | Funcref | Externref
+   type val_type = I32 | I64 | F32 | F64 | Funcref | Externref | Exnref
 
    func is_num(t : val_type) : bool =
      return t = I32 || t = I64 || t = F32 || t = F64
 
    func is_ref(t : val_type) : bool =
-     return t = Funcref || t = Externref
+     return t = Funcref || t = Externref || t = Exnref
 
 The algorithm uses two separate stacks: the *value stack* and the *control stack*.
 The former tracks the :ref:`types <syntax-valtype>` of operand values on the :ref:`stack <stack>`,

document/core/appendix/implementation.rst

@@ -36,6 +36,7 @@ An implementation may impose restrictions on the following dimensions of a modul
 * the number of :ref:`functions <syntax-func>` in a :ref:`module <syntax-module>`, including imports
 * the number of :ref:`tables <syntax-table>` in a :ref:`module <syntax-module>`, including imports
 * the number of :ref:`memories <syntax-mem>` in a :ref:`module <syntax-module>`, including imports
+* the number of :ref:`events <syntax-event>` in a :ref:`module <syntax-module>`, including imports
 * the number of :ref:`globals <syntax-global>` in a :ref:`module <syntax-module>`, including imports
 * the number of :ref:`element segments <syntax-elem>` in a :ref:`module <syntax-module>`
 * the number of :ref:`data segments <syntax-data>` in a :ref:`module <syntax-module>`
@@ -123,6 +124,7 @@ Restrictions on the following dimensions may be imposed during :ref:`execution <
 * the number of allocated :ref:`function instances <syntax-funcinst>`
 * the number of allocated :ref:`table instances <syntax-tableinst>`
 * the number of allocated :ref:`memory instances <syntax-meminst>`
+* the number of allocated :ref:`event instances <syntax-eventinst>`
 * the number of allocated :ref:`global instances <syntax-globalinst>`
 * the size of a :ref:`table instance <syntax-tableinst>`
 * the size of a :ref:`memory instance <syntax-meminst>`

document/core/appendix/index-instructions.rst

@@ -13,11 +13,11 @@ Instruction                                Binary Opcode              Type
 :math:`\LOOP~\X{bt}`                       :math:`\hex{03}`           :math:`[t_1^\ast] \to [t_2^\ast]`              :ref:`validation <valid-loop>`            :ref:`execution <exec-loop>`
 :math:`\IF~\X{bt}`                         :math:`\hex{04}`           :math:`[t_1^\ast] \to [t_2^\ast]`              :ref:`validation <valid-if>`              :ref:`execution <exec-if>`
 :math:`\ELSE`                              :math:`\hex{05}`
-(reserved)                                 :math:`\hex{06}`
-(reserved)                                 :math:`\hex{07}`
-(reserved)                                 :math:`\hex{08}`
-(reserved)                                 :math:`\hex{09}`
-(reserved)                                 :math:`\hex{0A}`
+:math:`\TRY~\X{bt}`                        :math:`\hex{06}`           :math:`[t_1^\ast] \to [t_2^\ast]`              :ref:`validation <valid-try>`             :ref:`execution <exec-try>`
+:math:`\CATCH`                             :math:`\hex{07}`
+:math:`\THROW~x`                           :math:`\hex{08}`           :math:`[t_1^\ast~t^\ast] \to [t_2^\ast]`       :ref:`validation <valid-throw>`           :ref:`execution <exec-throw>`
+:math:`\RETHROW`                           :math:`\hex{09}`           :math:`[t_1^\ast~\EXNREF] \to [t_2^\ast]`      :ref:`validation <valid-rethrow>`         :ref:`execution <exec-rethrow>`
+:math:`\BRONEXN~l~x`                       :math:`\hex{0A}`           :math:`[\EXNREF] \to [\EXNREF]`                :ref:`validation <valid-br_on_exn>`       :ref:`execution <exec-br_on_exn>`
 :math:`\END`                               :math:`\hex{0B}`
 :math:`\BR~l`                              :math:`\hex{0C}`           :math:`[t_1^\ast~t^\ast] \to [t_2^\ast]`       :ref:`validation <valid-br>`              :ref:`execution <exec-br>`
 :math:`\BRIF~l`                            :math:`\hex{0D}`           :math:`[t^\ast~\I32] \to [t^\ast]`             :ref:`validation <valid-br_if>`           :ref:`execution <exec-br_if>`

document/core/appendix/index-rules.rst

@@ -18,6 +18,7 @@ Construct                                        Judgement
 :ref:`Block type <valid-blocktype>`              :math:`\vdashblocktype \blocktype \ok`
 :ref:`Table type <valid-tabletype>`              :math:`\vdashtabletype \tabletype \ok`
 :ref:`Memory type <valid-memtype>`               :math:`\vdashmemtype \memtype \ok`
+:ref:`Event type <valid-eventtype>`              :math:`\vdasheventtype \eventtype \ok`
 :ref:`Global type <valid-globaltype>`            :math:`\vdashglobaltype \globaltype \ok`
 :ref:`External type <valid-externtype>`          :math:`\vdashexterntype \externtype \ok`
 :ref:`Instruction <valid-instr>`                 :math:`S;C \vdashinstr \instr : \functype`
@@ -26,6 +27,7 @@ Construct                                        Judgement
 :ref:`Function <valid-func>`                     :math:`C \vdashfunc \func : \functype`
 :ref:`Table <valid-table>`                       :math:`C \vdashtable \table : \tabletype`
 :ref:`Memory <valid-mem>`                        :math:`C \vdashmem \mem : \memtype`
+:ref:`Event <valid-event>`                       :math:`C \vdashevent \event : \eventtype`
 :ref:`Global <valid-global>`                     :math:`C \vdashglobal \global : \globaltype`
 :ref:`Element segment <valid-elem>`              :math:`C \vdashelem \elem : \reftype`
 :ref:`Element mode <valid-elemmode>`             :math:`C \vdashelemmode \elemmode : \reftype`
@@ -54,6 +56,7 @@ Construct                                        Judgement
 :ref:`Function instance <valid-funcinst>`        :math:`S \vdashfuncinst \funcinst : \functype`
 :ref:`Table instance <valid-tableinst>`          :math:`S \vdashtableinst \tableinst : \tabletype`
 :ref:`Memory instance <valid-meminst>`           :math:`S \vdashmeminst \meminst : \memtype`
+:ref:`Event instance <valid-eventinst>`          :math:`S \vdasheventinst \eventinst : \eventtype`
 :ref:`Global instance <valid-globalinst>`        :math:`S \vdashglobalinst \globalinst : \globaltype`
 :ref:`Element instance <valid-eleminst>`         :math:`S \vdasheleminst \eleminst \ok`
 :ref:`Data instance <valid-datainst>`            :math:`S \vdashdatainst \datainst \ok`
@@ -97,6 +100,7 @@ Construct                                        Judgement
 :ref:`Function instance <extend-funcinst>`       :math:`\vdashfuncinstextends \funcinst_1 \extendsto \funcinst_2`
 :ref:`Table instance <extend-tableinst>`         :math:`\vdashtableinstextends \tableinst_1 \extendsto \tableinst_2`
 :ref:`Memory instance <extend-meminst>`          :math:`\vdashmeminstextends \meminst_1 \extendsto \meminst_2`
+:ref:`Event instance <extend-eventinst>`          :math:`\vdasheventinstextends \eventinst_1 \extendsto \eventinst_2`
 :ref:`Global instance <extend-globalinst>`       :math:`\vdashglobalinstextends \globalinst_1 \extendsto \globalinst_2`
 :ref:`Element instance <extend-eleminst>`         :math:`\vdasheleminstextends \eleminst_1 \extendsto \eleminst_2`
 :ref:`Data instance <extend-datainst>`           :math:`\vdashdatainstextends \datainst_1 \extendsto \datainst_2`

document/core/appendix/index-types.rst

@@ -15,11 +15,13 @@ Category                                  Constructor
 (reserved)                                                                             :math:`\hex{7B}` .. :math:`\hex{71}`
 :ref:`Reference type <syntax-reftype>`    |FUNCREF|                                    :math:`\hex{70}` (-16 as |Bs7|)
 :ref:`Reference type <syntax-reftype>`    |EXTERNREF|                                  :math:`\hex{6F}` (-17 as |Bs7|)
-(reserved)                                                                             :math:`\hex{6E}` .. :math:`\hex{61}`
+:ref:`Reference type <syntax-reftype>`    |EXNREF|                                     :math:`\hex{6E}` (-18 as |Bs7|)
+(reserved)                                                                             :math:`\hex{6D}` .. :math:`\hex{61}`
 :ref:`Function type <syntax-functype>`    :math:`[\valtype^\ast] \to [\valtype^\ast]`  :math:`\hex{60}` (-32 as |Bs7|)
 (reserved)                                                                             :math:`\hex{5F}` .. :math:`\hex{41}`
 :ref:`Result type <syntax-resulttype>`    :math:`[\epsilon]`                             :math:`\hex{40}` (-64 as |Bs7|)
 :ref:`Table type <syntax-tabletype>`      :math:`\limits~\reftype`                     (none)
 :ref:`Memory type <syntax-memtype>`       :math:`\limits`                              (none)
+:ref:`Event type <syntax-eventtype>`      :math:`\EXCEPTION~\functype`                 (none)
 :ref:`Global type <syntax-globaltype>`    :math:`\mut~\valtype`                        (none)
 ========================================  ===========================================  ===============================================================================