From 587dafb42fe07e81ab779d987ff3bb0682da6d47 Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Thu, 16 Mar 2023 16:25:47 -0700
Subject: [PATCH 01/20] Add exceptional return to func_invoke in embedding doc

This is a basic start of what we'll need to add to the embedder spec.
I'm not sure if we also need a way to allow exceptions to bubble
from the embedder into wasm ; I don't see any reference to what
happens when the instance wants to call an import, so maybe not.
Also the references aren't quite right, but I may need help
to fix that
---
 document/core/appendix/embedding.rst | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/document/core/appendix/embedding.rst b/document/core/appendix/embedding.rst
index b4ad120d7..c8b8a85e1 100644
--- a/document/core/appendix/embedding.rst
+++ b/document/core/appendix/embedding.rst
@@ -293,14 +293,16 @@ Functions
 .. index:: invocation, value, result
 .. _embed-func-invoke:
 
-:math:`\F{func\_invoke}(\store, \funcaddr, \val^\ast) : (\store, \val^\ast ~|~ \error)`
-........................................................................................
+:math:`\F{func\_invoke}(\store, \funcaddr, \val^\ast) : (\store, \val^\ast ~|~ \error ~|~ \exception)`
+......................................................................................................
 
 1. Try :ref:`invoking <exec-invocation>` the function :math:`\funcaddr` in :math:`\store` with :ref:`values <syntax-val>` :math:`\val^\ast` as arguments:
 
   a. If it succeeds with :ref:`values <syntax-val>` :math:`{\val'}^\ast` as results, then let :math:`\X{result}` be :math:`{\val'}^\ast`.
 
-  b. Else it has trapped, hence let :math:`\X{result}` be :math:`\ERROR`.
+  b. Else if the result is a :ref:`throw context <syntax-throw-contexts>` for an uncaught exception with :ref:`tag <syntax-tag-instances>` :math:`{\tag}` and payload :ref:`values <syntax-val>` :math:`{\val'}^\ast`,  let :math:`\X{result}` be :math:`{tag'}`, :math:`{\val'}`.
+
+  c. Else it has trapped, hence let :math:`\X{result}` be :math:`\ERROR`.
 
 2. Return the new store paired with :math:`\X{result}`.
 
@@ -309,6 +311,7 @@ Functions
    \begin{array}{lclll}
    \F{func\_invoke}(S, a, v^\ast) &=& (S', {v'}^\ast) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; {v'}^\ast) \\
    \F{func\_invoke}(S, a, v^\ast) &=& (S', \ERROR) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; \TRAP) \\
+   \F{func\_invoke}(S, a, v^\ast) &=& (S', {v}, {v'}^\ast) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; \THROW) \\
    \end{array}
 
 .. note::

From 15a47cff3cf5b52390e4ae8d0a76d3effa934a5b Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Mon, 27 Mar 2023 10:27:01 -0700
Subject: [PATCH 02/20] review comments

---
 document/core/Makefile               |  4 ++--
 document/core/appendix/embedding.rst | 17 +++++++++++++++--
 document/core/util/macros.def        |  2 ++
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/document/core/Makefile b/document/core/Makefile
index 3ff1a87cb..3cd7c9470 100644
--- a/document/core/Makefile
+++ b/document/core/Makefile
@@ -136,13 +136,13 @@ singlehtml:
 bikeshed:
 	$(SPHINXBUILD) -b singlehtml -c util/bikeshed \
 		$(ALLSPHINXOPTS) $(BUILDDIR)/bikeshed_singlehtml
-	python util/bikeshed_fixup.py $(BUILDDIR)/bikeshed_singlehtml/index.html \
+	python3 util/bikeshed_fixup.py $(BUILDDIR)/bikeshed_singlehtml/index.html \
 		>$(BUILDDIR)/bikeshed_singlehtml/index_fixed.html
 	mkdir -p $(BUILDDIR)/bikeshed_mathjax/
 	bikeshed spec index.bs $(BUILDDIR)/bikeshed_mathjax/index.html
 	mkdir -p $(BUILDDIR)/html/bikeshed/
 	(cd util/katex/ && yarn && yarn build && npm install --only=prod)
-	python util/mathjax2katex.py $(BUILDDIR)/bikeshed_mathjax/index.html \
+	python3 util/mathjax2katex.py $(BUILDDIR)/bikeshed_mathjax/index.html \
 		>$(BUILDDIR)/html/bikeshed/index.html
 	mkdir -p $(BUILDDIR)/html/bikeshed/katex/dist/
 	cp -r util/katex/dist/* $(BUILDDIR)/html/bikeshed/katex/dist/
diff --git a/document/core/appendix/embedding.rst b/document/core/appendix/embedding.rst
index c8b8a85e1..11a475475 100644
--- a/document/core/appendix/embedding.rst
+++ b/document/core/appendix/embedding.rst
@@ -43,6 +43,19 @@ In addition to the error conditions specified explicitly in this section, implem
    Implementations can refine it to carry suitable classifications and diagnostic messages.
 
 
+.. _embed-exception:
+
+Exceptions
+~~~~~~~~~~
+
+Invoke operations may throw or propagate exceptions, indicated by an auxiliary syntactic class:
+
+.. math::
+   \begin{array}{llllll}
+   \production{exception} & \exception &::=& \ETHROW & exnaddr & val^\ast \\
+   \end{array}
+
+
 Pre- and Post-Conditions
 ~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -300,7 +313,7 @@ Functions
 
   a. If it succeeds with :ref:`values <syntax-val>` :math:`{\val'}^\ast` as results, then let :math:`\X{result}` be :math:`{\val'}^\ast`.
 
-  b. Else if the result is a :ref:`throw context <syntax-throw-contexts>` for an uncaught exception with :ref:`tag <syntax-tag-instances>` :math:`{\tag}` and payload :ref:`values <syntax-val>` :math:`{\val'}^\ast`,  let :math:`\X{result}` be :math:`{tag'}`, :math:`{\val'}`.
+  b. Else if the outcome is an exception with :ref:`tag <syntax-tagaddr>` :math:`\tagaddr` and payload :ref:`values <syntax-val>` :math:`{\val'}^\ast`,  let :math:`\X{result}` be :math:`\ETHROW~\tagaddr~{\val'}^\ast`.
 
   c. Else it has trapped, hence let :math:`\X{result}` be :math:`\ERROR`.
 
@@ -310,8 +323,8 @@ Functions
    ~ \\
    \begin{array}{lclll}
    \F{func\_invoke}(S, a, v^\ast) &=& (S', {v'}^\ast) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; {v'}^\ast) \\
+   \F{func\_invoke}(S, a, v^\ast) &=& (S', \ETHROW~a'~{v'}^\ast) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; \XT[(\THROWadm~a')]) \\
    \F{func\_invoke}(S, a, v^\ast) &=& (S', \ERROR) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; \TRAP) \\
-   \F{func\_invoke}(S, a, v^\ast) &=& (S', {v}, {v'}^\ast) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; \THROW) \\
    \end{array}
 
 .. note::
diff --git a/document/core/util/macros.def b/document/core/util/macros.def
index eae5e93f4..df1d63686 100644
--- a/document/core/util/macros.def
+++ b/document/core/util/macros.def
@@ -1323,3 +1323,5 @@
 
 .. |error| mathdef:: \xref{appendix/embedding}{embed-error}{\X{error}}
 .. |ERROR| mathdef:: \xref{appendix/embedding}{embed-error}{\K{error}}
+.. |exception| mathdef:: \xref{appendix/embedding}{embed-exception}{\X{exception}}
+.. |ETHROW| mathdef:: \xref{appendix/embedding}{embed-exception}{\K{THROW}}

From 904a8fbc0abb5f14e5112f154afb5a2938f6e37f Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Thu, 30 Mar 2023 16:21:12 -0700
Subject: [PATCH 03/20] swap order of error/exception in func_invoke

---
 document/core/appendix/embedding.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/document/core/appendix/embedding.rst b/document/core/appendix/embedding.rst
index 11a475475..c27c02328 100644
--- a/document/core/appendix/embedding.rst
+++ b/document/core/appendix/embedding.rst
@@ -306,7 +306,7 @@ Functions
 .. index:: invocation, value, result
 .. _embed-func-invoke:
 
-:math:`\F{func\_invoke}(\store, \funcaddr, \val^\ast) : (\store, \val^\ast ~|~ \error ~|~ \exception)`
+:math:`\F{func\_invoke}(\store, \funcaddr, \val^\ast) : (\store, \val^\ast ~|~ \exception ~|~ \error)`
 ......................................................................................................
 
 1. Try :ref:`invoking <exec-invocation>` the function :math:`\funcaddr` in :math:`\store` with :ref:`values <syntax-val>` :math:`\val^\ast` as arguments:

From ec302e1aeb76364816fd51f6e437ef27d73fba5c Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Tue, 11 Apr 2023 15:33:13 -0700
Subject: [PATCH 04/20] review suggestions

---
 document/core/appendix/embedding.rst | 24 +++++++++++-------------
 document/core/util/macros.def        |  4 ++--
 2 files changed, 13 insertions(+), 15 deletions(-)

diff --git a/document/core/appendix/embedding.rst b/document/core/appendix/embedding.rst
index c27c02328..d827edcaa 100644
--- a/document/core/appendix/embedding.rst
+++ b/document/core/appendix/embedding.rst
@@ -26,8 +26,17 @@ For numeric parameters, notation like :math:`n:\u32` is used to specify a symbol
 
 .. _embed-error:
 
-Errors
-~~~~~~
+Exceptions and Errors
+~~~~~~~~~~~~~~~~~~~~~
+
+Invoke operations may throw or propagate exceptions, indicated by an auxiliary syntactic class:
+
+.. math::
+   \begin{array}{llll}
+   \production{exception} & \exception &::=& \ETHROW ~ \tagaddr ~ val^\ast \\
+   \end{array}
+
+The tag instance :math:`tagaddr` identifies the :ref:`type <syntax-tagtype>` of exception thrown. The values :math:`val^\ast` are the exception's payload; their types match the tag type's parameters.
 
 Failure of an interface operation is indicated by an auxiliary syntactic class:
 
@@ -43,17 +52,6 @@ In addition to the error conditions specified explicitly in this section, implem
    Implementations can refine it to carry suitable classifications and diagnostic messages.
 
 
-.. _embed-exception:
-
-Exceptions
-~~~~~~~~~~
-
-Invoke operations may throw or propagate exceptions, indicated by an auxiliary syntactic class:
-
-.. math::
-   \begin{array}{llllll}
-   \production{exception} & \exception &::=& \ETHROW & exnaddr & val^\ast \\
-   \end{array}
 
 
 Pre- and Post-Conditions
diff --git a/document/core/util/macros.def b/document/core/util/macros.def
index df1d63686..13e904d7a 100644
--- a/document/core/util/macros.def
+++ b/document/core/util/macros.def
@@ -1323,5 +1323,5 @@
 
 .. |error| mathdef:: \xref{appendix/embedding}{embed-error}{\X{error}}
 .. |ERROR| mathdef:: \xref{appendix/embedding}{embed-error}{\K{error}}
-.. |exception| mathdef:: \xref{appendix/embedding}{embed-exception}{\X{exception}}
-.. |ETHROW| mathdef:: \xref{appendix/embedding}{embed-exception}{\K{THROW}}
+.. |exception| mathdef:: \xref{appendix/embedding}{embed-error}{\X{exception}}
+.. |ETHROW| mathdef:: \xref{appendix/embedding}{embed-error}{\K{THROW}}

From fdf1b7c2a9553fec8734b3c15199a16b0cb47ca8 Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Wed, 3 May 2023 17:35:56 -0700
Subject: [PATCH 05/20] Apply suggestions from code review

Co-authored-by: Andreas Rossberg <rossberg@dfinity.org>
---
 document/core/appendix/embedding.rst | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/document/core/appendix/embedding.rst b/document/core/appendix/embedding.rst
index d827edcaa..d11da93bf 100644
--- a/document/core/appendix/embedding.rst
+++ b/document/core/appendix/embedding.rst
@@ -29,16 +29,16 @@ For numeric parameters, notation like :math:`n:\u32` is used to specify a symbol
 Exceptions and Errors
 ~~~~~~~~~~~~~~~~~~~~~
 
-Invoke operations may throw or propagate exceptions, indicated by an auxiliary syntactic class:
+Invoking an exported function may throw or propagate exceptions, expressed by an auxiliary syntactic class:
 
 .. math::
    \begin{array}{llll}
    \production{exception} & \exception &::=& \ETHROW ~ \tagaddr ~ val^\ast \\
    \end{array}
 
-The tag instance :math:`tagaddr` identifies the :ref:`type <syntax-tagtype>` of exception thrown. The values :math:`val^\ast` are the exception's payload; their types match the tag type's parameters.
+The tag instance :math:`tagaddr` identifies the exception thrown. The values :math:`val^\ast` are the exception's payload; their types match the tag type's parameters.
 
-Failure of an interface operation is indicated by an auxiliary syntactic class:
+Failure of an interface operation is also indicated by an auxiliary syntactic class:
 
 .. math::
    \begin{array}{llll}

From f57cdb8cc4c5e374cc5ae59e9de2eee38c843d80 Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Thu, 21 Mar 2024 17:30:31 -0700
Subject: [PATCH 06/20] add exception allocation

---
 document/core/appendix/embedding.rst | 38 ++++++++++++++++++++++++++++
 document/core/exec/instructions.rst  | 16 +++++-------
 document/core/exec/modules.rst       | 28 +++++++++++++++++++-
 document/core/util/macros.def        |  1 +
 4 files changed, 73 insertions(+), 10 deletions(-)

diff --git a/document/core/appendix/embedding.rst b/document/core/appendix/embedding.rst
index 5413799f8..13dd1ed37 100644
--- a/document/core/appendix/embedding.rst
+++ b/document/core/appendix/embedding.rst
@@ -576,6 +576,44 @@ Tags
    \end{array}
 
 
+.. _embed-tag-type:
+
+:math:`\F{tag\_type}(\store, \tagaddr) : \tagtype`
+........................................................
+
+1. Return :math:`S.\STAGS[a].\TAGITYPE`.
+
+2. Post-condition: the returned :ref:`tag type <syntax-tagtype>` is :ref:`valid  <valid-tagtype>`.
+
+.. math::
+   \begin{array}{lclll}
+   \F{tag\_type}(S, a) &=& S.\STAGS[a].\TAGITYPE \\
+   \end{array}
+
+
+.. index:: exception, exception address, store, exception instance, exception type
+.. _embed-exception:
+
+Exceptions
+~~~~~~~~~~
+
+.. _embed-exception-alloc:
+
+:math:`\F{exception\_alloc}(\store, \tagaddr, \val) : (\store, \exnaddr)`
+............................................................................
+
+1. Pre-condition: :math:`\tagaddr` is an allocated :ref:`tag address <syntax-tagaddr>`.
+
+2. Let :math:`\exnaddr` be the result of :ref:`allocating an exception <alloc-exception>` in :math:`\store` with :ref:`tag address <syntax-tagaddr>` :math:`\tagaddr` and initialization values :math:`\val^\ast`.
+
+3. Return the new store paired with :math:`\exnaddr`.
+
+.. math::
+   \begin{array}{lclll}
+   \F{exception\_alloc}(S, \X{gt}, v) &=& (S', \X{a}) && (\iff \allocglobal(S, \X{gt}, v) = S', \X{a}) \\
+   \end{array}
+
+
 .. index:: global, global address, store, global instance, global type, value
 .. _embed-global:
 
diff --git a/document/core/exec/instructions.rst b/document/core/exec/instructions.rst
index 5d19010c1..5ee4a6051 100644
--- a/document/core/exec/instructions.rst
+++ b/document/core/exec/instructions.rst
@@ -2719,11 +2719,11 @@ Control Instructions
 
 2. Assert: due to :ref:`validation <valid-throw>`, :math:`F.\AMODULE.\MITAGS[x]` exists.
 
-3. Let :math:`a` be the :ref:`tag address <syntax-tagaddr>` :math:`F.\AMODULE.\MITAGS[x]`.
+3. Let :math:`ta` be the :ref:`tag address <syntax-tagaddr>` :math:`F.\AMODULE.\MITAGS[x]`.
 
-4. Assert: due to :ref:`validation <valid-throw>`, :math:`S.\STAGS[a]` exists.
+4. Assert: due to :ref:`validation <valid-throw>`, :math:`S.\STAGS[ta]` exists.
 
-5. Let :math:`\X{ti}` be the :ref:`tag instance <syntax-taginst>` :math:`S.\STAGS[a]`.
+5. Let :math:`\X{ti}` be the :ref:`tag instance <syntax-taginst>` :math:`S.\STAGS[ta]`.
 
 6. Let :math:`[t^n] \toF [{t'}^\ast]` be the :ref:`tag type <syntax-tagtype>` :math:`\X{ti}.\TAGITYPE`.
 
@@ -2731,15 +2731,13 @@ Control Instructions
 
 8. Pop the :math:`n` values :math:`\val^n` from the stack.
 
-9. Let :math:`\X{exn}` be the :ref:`exception instance <syntax-exninst>` :math:`\{ \EITAG~a, \EIFIELDS~\val^n \}`.
+9. Let :math:`\X{ea}` be the :ref:`exception address <syntax-exnaddr>` resulting from :ref:`allocating <alloc-exception>` an exception instance with tag address :math:`ta` and initializer values :math:`\val^n`.
 
-10. Let :math:`\X{ea}` be the length of :math:`S.\SEXNS`.
+10. Let :math:`\X{exn}` be :math:`S.\SEXNS[ea]`
 
-11. Append :math:`\X{exn}` to :math:`S.\SEXNS`.
+11. Push the value :math:`\REFEXNADDR~\X{ea}` to the stack.
 
-12. Push the value :math:`\REFEXNADDR~\X{ea}` to the stack.
-
-13. Execute the instruction |THROWREF|.
+12. Execute the instruction |THROWREF|.
 
 .. math::
    ~\\[-1ex]
diff --git a/document/core/exec/modules.rst b/document/core/exec/modules.rst
index a43f55e91..4f1335f1d 100644
--- a/document/core/exec/modules.rst
+++ b/document/core/exec/modules.rst
@@ -190,7 +190,7 @@ The following auxiliary typing rules specify this typing relation relative to a
 Allocation
 ~~~~~~~~~~
 
-New instances of :ref:`functions <syntax-funcinst>`, :ref:`tables <syntax-tableinst>`, :ref:`memories <syntax-meminst>`, :ref:`tags <syntax-taginst>`, and :ref:`globals <syntax-globalinst>` are *allocated* in a :ref:`store <syntax-store>` :math:`S`, as defined by the following auxiliary functions.
+New instances of :ref:`functions <syntax-funcinst>`, :ref:`tables <syntax-tableinst>`, :ref:`memories <syntax-meminst>`, :ref:`tags <syntax-taginst>`, :ref:`exceptions <syntax-exninst>`, and :ref:`globals <syntax-globalinst>` are *allocated* in a :ref:`store <syntax-store>` :math:`S`, as defined by the following auxiliary functions.
 
 
 .. index:: function, function instance, function address, module instance, function type
@@ -338,6 +338,32 @@ New instances of :ref:`functions <syntax-funcinst>`, :ref:`tables <syntax-tablei
    \end{array}
 
 
+.. index:: exception, exception instance, exception address, tag address
+.. _alloc-exception:
+
+:ref:`Exceptions <syntax-exninst>`
+..................................
+
+1. Let :math:`ta` be the :ref:`tag address <syntax-tagaddr>` associated with the exception to allocate and :math:`\EIFIELDS~\val^\ast` be the values to initialize the exception with.
+
+2. Let :math:`a` be the first free :ref:`exception address <syntax-exnaddr>` in :math:`S`.
+
+3. Let :math:`\exninst` be the :ref:`exception instance <syntax-exninst>` :math:`\{ \EITAG~ta, \EIFIELDS~\val^\ast \}`. 
+
+4. Append :math:`\exninst` to the |SEXNS| of :math:`S`.
+
+5. Return :math:`a`.
+
+.. math::
+   \begin{array}{rlll}
+   \allocexn(S, \tagaddr, \val^ast) &=& S', \exnaddr \\[1ex]
+   \mbox{where:} \hfill \\
+   \exnaddr &=& |S.\SEXNS| \\
+   \exninst &=& \{ \EITAG~\tagaddr, \GIVALUE~\val^\ast \} \\
+   S' &=& S \compose \{\SEXNS~\exninst\} \\
+   \end{array}
+
+
 .. index:: global, global instance, global address, global type, value type, mutability, value
 .. _alloc-global:
 
diff --git a/document/core/util/macros.def b/document/core/util/macros.def
index ca40cd52b..ed0da3328 100644
--- a/document/core/util/macros.def
+++ b/document/core/util/macros.def
@@ -981,6 +981,7 @@
 .. |alloctable| mathdef:: \xref{exec/modules}{alloc-table}{\F{alloctable}}
 .. |allocmem| mathdef:: \xref{exec/modules}{alloc-mem}{\F{allocmem}}
 .. |alloctag| mathdef:: \xref{exec/modules}{alloc-tag}{\F{alloctag}}
+.. |allocexn| mathdef:: \xref{exec/modules}{alloc-exception}{\F{allocexn}}
 .. |allocglobal| mathdef:: \xref{exec/modules}{alloc-global}{\F{allocglobal}}
 .. |allocelem| mathdef:: \xref{exec/modules}{alloc-elem}{\F{allocelem}}
 .. |allocdata| mathdef:: \xref{exec/modules}{alloc-data}{\F{allocdata}}

From ccbee0f7e15d277067fc81fdbad5100eb91c253e Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Fri, 22 Mar 2024 10:42:43 -0700
Subject: [PATCH 07/20] udpate for exnref

---
 document/core/appendix/embedding.rst | 4 ++--
 document/core/exec/modules.rst       | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/document/core/appendix/embedding.rst b/document/core/appendix/embedding.rst
index 13dd1ed37..7f75fb76d 100644
--- a/document/core/appendix/embedding.rst
+++ b/document/core/appendix/embedding.rst
@@ -311,7 +311,7 @@ Functions
 
   a. If it succeeds with :ref:`values <syntax-val>` :math:`{\val'}^\ast` as results, then let :math:`\X{result}` be :math:`{\val'}^\ast`.
 
-  b. Else if the outcome is an exception with :ref:`tag <syntax-tagaddr>` :math:`\tagaddr` and payload :ref:`values <syntax-val>` :math:`{\val'}^\ast`,  let :math:`\X{result}` be :math:`\ETHROW~\tagaddr~{\val'}^\ast`.
+  b. Else if the outcome is an exception with a thrown :ref:`exception <exec-throw_ref>` :math:`\REFEXNADDR~\exnaddr` as the result, then let :math:`\X{result}` be :math:`\exnaddr`
 
   c. Else it has trapped, hence let :math:`\X{result}` be :math:`\ERROR`.
 
@@ -321,7 +321,7 @@ Functions
    ~ \\
    \begin{array}{lclll}
    \F{func\_invoke}(S, a, v^\ast) &=& (S', {v'}^\ast) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; {v'}^\ast) \\
-   \F{func\_invoke}(S, a, v^\ast) &=& (S', \ETHROW~a'~{v'}^\ast) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; \XT[(\THROWadm~a')]) \\
+   \F{func\_invoke}(S, a, v^\ast) &=& (S', \ETHROW~a'~{v'}^\ast) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; \XT[(\REFEXNADDR~\exnaddr)~\THROWREF] \\
    \F{func\_invoke}(S, a, v^\ast) &=& (S', \ERROR) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; \TRAP) \\
    \end{array}
 
diff --git a/document/core/exec/modules.rst b/document/core/exec/modules.rst
index 4f1335f1d..b2ebe665b 100644
--- a/document/core/exec/modules.rst
+++ b/document/core/exec/modules.rst
@@ -348,7 +348,7 @@ New instances of :ref:`functions <syntax-funcinst>`, :ref:`tables <syntax-tablei
 
 2. Let :math:`a` be the first free :ref:`exception address <syntax-exnaddr>` in :math:`S`.
 
-3. Let :math:`\exninst` be the :ref:`exception instance <syntax-exninst>` :math:`\{ \EITAG~ta, \EIFIELDS~\val^\ast \}`. 
+3. Let :math:`\exninst` be the :ref:`exception instance <syntax-exninst>` :math:`\{ \EITAG~ta, \EIFIELDS~\val^\ast \}`.
 
 4. Append :math:`\exninst` to the |SEXNS| of :math:`S`.
 

From 4d08a587f5cb8654c2347027cb1a6a3940c554d5 Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Fri, 29 Mar 2024 10:29:10 -0700
Subject: [PATCH 08/20] apply all suggestions other than exn_read

---
 document/core/appendix/embedding.rst | 14 +++++++-------
 document/core/exec/modules.rst       |  4 ++--
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/document/core/appendix/embedding.rst b/document/core/appendix/embedding.rst
index 7f75fb76d..65723a471 100644
--- a/document/core/appendix/embedding.rst
+++ b/document/core/appendix/embedding.rst
@@ -33,10 +33,10 @@ Invoking an exported function may throw or propagate exceptions, expressed by an
 
 .. math::
    \begin{array}{llll}
-   \production{exception} & \exception &::=& \ETHROW ~ \tagaddr ~ val^\ast \\
+   \production{exception} & \exception &::=& \ETHROW ~ \exnaddr \\
    \end{array}
 
-The tag instance :math:`tagaddr` identifies the exception thrown. The values :math:`val^\ast` are the exception's payload; their types match the tag type's parameters.
+The exception instance :math:`exnaddr` identifies the exception thrown.
 
 Failure of an interface operation is also indicated by an auxiliary syntactic class:
 
@@ -311,7 +311,7 @@ Functions
 
   a. If it succeeds with :ref:`values <syntax-val>` :math:`{\val'}^\ast` as results, then let :math:`\X{result}` be :math:`{\val'}^\ast`.
 
-  b. Else if the outcome is an exception with a thrown :ref:`exception <exec-throw_ref>` :math:`\REFEXNADDR~\exnaddr` as the result, then let :math:`\X{result}` be :math:`\exnaddr`
+  b. Else if the outcome is an exception with a thrown :ref:`exception <exec-throw_ref>` :math:`\REFEXNADDR~\exnaddr` as the result, then let :math:`\X{result}` be :math:`\ETHROW~\exnaddr`
 
   c. Else it has trapped, hence let :math:`\X{result}` be :math:`\ERROR`.
 
@@ -321,7 +321,7 @@ Functions
    ~ \\
    \begin{array}{lclll}
    \F{func\_invoke}(S, a, v^\ast) &=& (S', {v'}^\ast) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; {v'}^\ast) \\
-   \F{func\_invoke}(S, a, v^\ast) &=& (S', \ETHROW~a'~{v'}^\ast) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; \XT[(\REFEXNADDR~\exnaddr)~\THROWREF] \\
+   \F{func\_invoke}(S, a, v^\ast) &=& (S', \ETHROW~a') && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; \XT[(\REFEXNADDR~\exnaddr)~\THROWREF] \\
    \F{func\_invoke}(S, a, v^\ast) &=& (S', \ERROR) && (\iff \invoke(S, a, v^\ast) \stepto^\ast S'; F; \TRAP) \\
    \end{array}
 
@@ -597,9 +597,9 @@ Tags
 Exceptions
 ~~~~~~~~~~
 
-.. _embed-exception-alloc:
+.. _embed-exn-alloc:
 
-:math:`\F{exception\_alloc}(\store, \tagaddr, \val) : (\store, \exnaddr)`
+:math:`\F{exn\_alloc}(\store, \tagaddr, \val^\ast) : (\store, \exnaddr)`
 ............................................................................
 
 1. Pre-condition: :math:`\tagaddr` is an allocated :ref:`tag address <syntax-tagaddr>`.
@@ -610,7 +610,7 @@ Exceptions
 
 .. math::
    \begin{array}{lclll}
-   \F{exception\_alloc}(S, \X{gt}, v) &=& (S', \X{a}) && (\iff \allocglobal(S, \X{gt}, v) = S', \X{a}) \\
+   \F{exn\_alloc}(S, \tagaddr, \val^\ast) &=& (S', a) && (\iff \allocexn(S, \tagaddr, \val^\ast) = S', a) \\
    \end{array}
 
 
diff --git a/document/core/exec/modules.rst b/document/core/exec/modules.rst
index b2ebe665b..2a52bc96f 100644
--- a/document/core/exec/modules.rst
+++ b/document/core/exec/modules.rst
@@ -356,10 +356,10 @@ New instances of :ref:`functions <syntax-funcinst>`, :ref:`tables <syntax-tablei
 
 .. math::
    \begin{array}{rlll}
-   \allocexn(S, \tagaddr, \val^ast) &=& S', \exnaddr \\[1ex]
+   \allocexn(S, \tagaddr, \val^\ast) &=& S', \exnaddr \\[1ex]
    \mbox{where:} \hfill \\
    \exnaddr &=& |S.\SEXNS| \\
-   \exninst &=& \{ \EITAG~\tagaddr, \GIVALUE~\val^\ast \} \\
+   \exninst &=& \{ \EITAG~\tagaddr, \EIFIELDS~\val^\ast \} \\
    S' &=& S \compose \{\SEXNS~\exninst\} \\
    \end{array}
 

From 74a92cbec06defc66a7cb65d8c1b69c3040aeece Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Fri, 29 Mar 2024 10:50:20 -0700
Subject: [PATCH 09/20] add exn_read

---
 document/core/appendix/embedding.rst | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/document/core/appendix/embedding.rst b/document/core/appendix/embedding.rst
index 65723a471..4c6791ae3 100644
--- a/document/core/appendix/embedding.rst
+++ b/document/core/appendix/embedding.rst
@@ -614,6 +614,21 @@ Exceptions
    \end{array}
 
 
+.. _embed-exn-read:
+
+:math:`\F{exn\_read}(\store, \exnaddr) : (\tagaddr, \val^\ast)`
+......................................................................
+
+1. Let :math:`\X{ei}` be the :ref:`exception instance <syntax-exninst>` :math:`\store.\SEXNS[\exnaddr]`.
+
+2. Return the :ref:`tag address <syntax-tagaddr>` :math:`\X{ei}.\EITAG~\tagaddr` paired with :ref:`values <syntax-val>` :math:`\X{ei}.\EIFIELDS~\val^\ast`.
+
+.. math::
+   \begin{array}{lcll}
+   \F{exn\_read}(S, a) &=& (a', v^\ast) \\
+   \end{array}
+
+
 .. index:: global, global address, store, global instance, global type, value
 .. _embed-global:
 

From b17459a537a527b5671c19163bf6176f49e39369 Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Fri, 29 Mar 2024 14:18:29 -0700
Subject: [PATCH 10/20] Update allocation, initialization, construction and
 call-exported-fn

---
 document/js-api/index.bs | 62 +++++++++++++++++++++++-----------------
 1 file changed, 35 insertions(+), 27 deletions(-)

diff --git a/document/js-api/index.bs b/document/js-api/index.bs
index 1519c0494..415b98160 100644
--- a/document/js-api/index.bs
+++ b/document/js-api/index.bs
@@ -27,7 +27,7 @@ Prepare For TR: true
 <pre class="anchors">
 urlPrefix: https://tc39.github.io/ecma262/; spec: ECMASCRIPT
     type: interface; for: ECMAScript
-        text: ArrayBuffer; url: sec-arraybuffer-objects
+        text: ArrayBuffer; url: sec-arraybuffπer-objects
     type: exception; for: ECMAScript
         text: Error; url: sec-error-objects
         text: NativeError; url: sec-nativeerror-constructors
@@ -238,6 +238,8 @@ Each [=agent=] is associated with the following [=ordered map=]s:
     * The <dfn>Global object cache</dfn>, mapping [=global address=]es to {{Global}} objects.
     * The <dfn>Extern value cache</dfn>, mapping [=extern address=]es to values.
     * The <dfn>Tag object cache</dfn>, mapping [=tag addresses=] to {{Tag}} objects.
+    * The <dfn>Exception object cache</dfn>, mapping [=exception address=]es to {{Exception}} objects.
+
 
 <h2 id="webassembly-namespace">The WebAssembly Namespace</h2>
 
@@ -760,7 +762,7 @@ Each {{Table}} object has a \[[Table]] internal slot, which is a [=table address
     The <dfn constructor for="Table">Table(|descriptor|, |value|)</dfn> constructor, when invoked, performs the following steps:
     1. Let |elementType| be [=ToValueType=](|descriptor|["element"]).
     1. If |elementType| is not a [=reftype=],
-        1. [=Throw=] a {{TypeError}} exception.
+        1. Throw a {{TypeError}} exception.
     1. Let |initial| be |descriptor|["initial"].
     1. If |descriptor|["maximum"] [=map/exists=], let |maximum| be |descriptor|["maximum"]; otherwise, let |maximum| be empty.
     1. If |maximum| is not empty and |maximum| &lt; |initial|, throw a {{RangeError}} exception.
@@ -1014,11 +1016,8 @@ This slot holds a [=function address=] relative to the [=surrounding agent=]'s [
     1. Note: The expectation is that [=func_invoke=] will be updated to return (|store|, <var ignore>val</var>* | [=error=] | (exception |exntag| |payload| |opaqueData|)).
     1. Set the [=surrounding agent=]'s [=associated store=] to |store|.
     1. If |ret| is [=error=], throw an exception. This exception should be a WebAssembly {{RuntimeError}} exception, unless otherwise indicated by <a href="#errors">the WebAssembly error mapping</a>.
-    1. If |ret| is exception |exntag| |payload| |opaqueData|, then
-        1. If |opaqueData| is not [=ref.null=] [=externref=],
-            1. Let « [=ref.extern=] |externaddr| » be |opaqueData|.
-            1. Throw the result of [=retrieving an extern value=] from |externaddr|.
-        1. Let |exception| be [=create an Exception object|a new Exception=] for |exntag| and |payload|.
+    1. If |ret| is [=THROW=] [=ref.exn=] |exnaddr|, then
+        1. Let |exception| be [=create an Exception object|a new Exception=] created from |exnaddr|.
         1. Throw |exception|.
     1. Let |outArity| be the [=list/size=] of |ret|.
     1. If |outArity| is 0, return undefined.
@@ -1048,7 +1047,7 @@ Note: Exported Functions do not have a \[[Construct]] method and thus it is not
     1. Otherwise, if |resultsSize| is 1, return « [=?=] [=ToWebAssemblyValue=](|ret|, |results|[0]) ».
     1. Otherwise,
         1. Let |method| be [=?=] [$GetMethod$](|ret|, {{@@iterator}}).
-        1. If |method| is undefined, [=throw=] a {{TypeError}}.
+        1. If |method| is undefined, throw a {{TypeError}}.
         1. Let |values| be [=?=] [$IterableToList$](|ret|, |method|).
         1. Let |wasmValues| be a new, empty [=list=].
         1. If |values|'s [=list/size=] is not |resultsSize|, throw a {{TypeError}} exception.
@@ -1263,21 +1262,31 @@ interface Exception {
 
 An {{Exception}} value represents an exception.
 
+<div algorithm>
+To <dfn>initialize an Exception object</dfn> |exn| from an [=Exception address=] |exnAddress|, perform the following steps:
+
+1. Let |map| be the [=surrounding agent=]'s associated [=Exception object cache=].
+1. Assert: |map|[|exnAddress|] doesn't [=map/exist=].
+1. Set |exn|.\[[Address]] to |exnAddress|.
+1. [=map/Set=] |map|[|exnAddress|] to |exn|.
+1. Let (|tagaddr|, |payload|) be [=exn_read=](|store|, |exnAddress|).
+1. Set |exn|.\[[Type]] to |tagaddr|.
+1. Set |exn|.\[[Payload]] to |payload|. (XXX use a getter?)
+1. Set |exn|.\[[Stack]] to undefined.
+</div>
+
 <div algorithm>
 
-To <dfn>create an Exception object</dfn> from a [=tag address=] |tagAddress| and a [=list=] of
+To <dfn>create an Exception object</dfn> from a [=exception address=] |exnAddress| and a [=list=] of
 WebAssembly values |payload|, perform the following steps:
 
-1. Let |store| be the [=surrounding agent=]'s [=associated store=].
-1. Let |types| be [=tag_parameters=](|store|, |tagAddress|).
-1. Assert: |types|'s [=list/size=] is |payload|'s [=list/size=].
-1. [=list/iterate|For each=] |value| and |resultType| of |payload| and |types|, paired linearly,
-    1. Assert: |value|'s type matches |resultType|.
-1. Let |exception| be a [=new=] {{Exception}}.
-1. Set |exception|.\[[Type]] to |tagAddress|.
-1. Set |exception|.\[[Payload]] to |payload|.
-1. Set |exception|.\[[Stack]] to undefined.
-1. Return |exception|.
+1. Let |map| be the [=surrounding agent=]'s associated [=Exception object cache=].
+1. If |map|[|exnAddress|] [=map/exists=],
+    1. Return |map|[|exnAddress|].
+1. Let |exn| be a [=new=] {{Exception}}.
+1. [=initialize an Exception object|Initialize=] |exn| from |exnAddress|.
+1. Return |exn|.
+
 
 </div>
 
@@ -1294,22 +1303,21 @@ constructor steps are:
 1. Let |wasmPayload| be « ».
 1. [=list/iterate|For each=] |value| and |resultType| of |payload| and |types|, paired linearly,
     1. [=list/Append=] ? [=ToWebAssemblyValue=](|value|, |resultType|) to |wasmPayload|.
-1. Set **this**.\[[Type]] to |exceptionTag|.\[[Address]].
-1. Set **this**.\[[Payload]] to |wasmPayload|.
+1. Let (|store|, |exceptionAddr|) be [=exn_alloc=](|store|, |exceptionTag|.\[[Address]], |wasmPayload|)
+1. [=initialize an Exception object|Initialize=] **this** from |exceptionAddr|.
 1. If |options|["traceStack"] is true,
     1. Set **this**.\[[Stack]] to either a {{DOMString}} representation of the current call stack or undefined.
-1. Otherwise,
-    1. Set **this**.\[[Stack]] to undefined.
+
 
 </div>
 
 <div algorithm>
 
-The <dfn method for="Exception">getArg(|exceptionTag|, |index|)</dfn> method steps are:
+The <dfn method for="Exception">getArg(|index|)</dfn> method steps are:
+(XXX maybe rename this method? exns don't really have 'args' the way func types do and also for backward compatibility)
 
-1. If **this**.\[[Type]] is not equal to |exceptionTag|.\[[Address]],
-    1. Throw a {{TypeError}}.
-1. Let |payload| be **this**.\[[Payload]].
+1. Let (|tagaddr|, |payload|) be [=exn_read=](|store|, **this**.\[[Address]]).
+1. Assert: |tagaddr| is equal to **this**.\[[Type]].
 1. If |index| ≥ |payload|'s [=list/size=],
     1. Throw a {{RangeError}}.
 1. Return [=ToJSValue=](|payload|[|index|]).

From fa07dea79dc04e900d0815c57eb373fc5b5ab60b Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Fri, 29 Mar 2024 15:12:28 -0700
Subject: [PATCH 11/20] fix linkage, syntax

---
 document/js-api/index.bs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/document/js-api/index.bs b/document/js-api/index.bs
index 415b98160..06518c0e6 100644
--- a/document/js-api/index.bs
+++ b/document/js-api/index.bs
@@ -64,6 +64,7 @@ urlPrefix: https://webassembly.github.io/exception-handling/core/; spec: WebAsse
         text: ref.null
         text: ref.func
         text: ref.extern
+        text: ref.exn
     text: function index; url: syntax/modules.html#syntax-funcidx
     text: function instance; url: exec/runtime.html#function-instances
     text: store_init; url: appendix/embedding.html#embed-store-init
@@ -101,6 +102,9 @@ urlPrefix: https://webassembly.github.io/exception-handling/core/; spec: WebAsse
     text: global address; url: exec/runtime.html#syntax-globaladdr
     text: extern address; url: exec/runtime.html#syntax-externaddr
     text: tag address; url: exec/runtime.html#syntax-tagaddr
+    text: exception address; url: exec/runtime.html#syntax-exnaddr
+    text: exn_alloc; url: appendix/embedding.html#embed-exn-alloc
+    text: exn_read; url: appendix/embedding.html#embed-exn-read
     url: syntax/types.html#syntax-numtype
         text: i32
         text: i64
@@ -1013,7 +1017,6 @@ This slot holds a [=function address=] relative to the [=surrounding agent=]'s [
         1. [=list/Append=] [=ToWebAssemblyValue=](|arg|, |t|) to |args|.
         1. Set |i| to |i| + 1.
     1. Let (|store|, |ret|) be the result of [=func_invoke=](|store|, |funcaddr|, |args|).
-    1. Note: The expectation is that [=func_invoke=] will be updated to return (|store|, <var ignore>val</var>* | [=error=] | (exception |exntag| |payload| |opaqueData|)).
     1. Set the [=surrounding agent=]'s [=associated store=] to |store|.
     1. If |ret| is [=error=], throw an exception. This exception should be a WebAssembly {{RuntimeError}} exception, unless otherwise indicated by <a href="#errors">the WebAssembly error mapping</a>.
     1. If |ret| is [=THROW=] [=ref.exn=] |exnaddr|, then
@@ -1273,6 +1276,7 @@ To <dfn>initialize an Exception object</dfn> |exn| from an [=Exception address=]
 1. Set |exn|.\[[Type]] to |tagaddr|.
 1. Set |exn|.\[[Payload]] to |payload|. (XXX use a getter?)
 1. Set |exn|.\[[Stack]] to undefined.
+
 </div>
 
 <div algorithm>

From ea5217b8b482d9419821d3635b473e83d45ca41c Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Fri, 29 Mar 2024 15:19:29 -0700
Subject: [PATCH 12/20] fix typo

---
 document/js-api/index.bs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/document/js-api/index.bs b/document/js-api/index.bs
index 06518c0e6..7a607a5fb 100644
--- a/document/js-api/index.bs
+++ b/document/js-api/index.bs
@@ -27,7 +27,7 @@ Prepare For TR: true
 <pre class="anchors">
 urlPrefix: https://tc39.github.io/ecma262/; spec: ECMASCRIPT
     type: interface; for: ECMAScript
-        text: ArrayBuffer; url: sec-arraybuffπer-objects
+        text: ArrayBuffer; url: sec-arraybuffer-objects
     type: exception; for: ECMAScript
         text: Error; url: sec-error-objects
         text: NativeError; url: sec-nativeerror-constructors

From 1c958c2f8c50c64daab12fa92ef053512f4cd08a Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Fri, 29 Mar 2024 15:38:22 -0700
Subject: [PATCH 13/20] fix vars

---
 document/js-api/index.bs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/document/js-api/index.bs b/document/js-api/index.bs
index 7a607a5fb..60702057d 100644
--- a/document/js-api/index.bs
+++ b/document/js-api/index.bs
@@ -1272,17 +1272,17 @@ To <dfn>initialize an Exception object</dfn> |exn| from an [=Exception address=]
 1. Assert: |map|[|exnAddress|] doesn't [=map/exist=].
 1. Set |exn|.\[[Address]] to |exnAddress|.
 1. [=map/Set=] |map|[|exnAddress|] to |exn|.
+1. Let |store| be the [=surrounding agent=]'s [=associated store=].
 1. Let (|tagaddr|, |payload|) be [=exn_read=](|store|, |exnAddress|).
 1. Set |exn|.\[[Type]] to |tagaddr|.
-1. Set |exn|.\[[Payload]] to |payload|. (XXX use a getter?)
+1. Set |exn|.\[[Payload]] to |payload|.
 1. Set |exn|.\[[Stack]] to undefined.
 
 </div>
 
 <div algorithm>
 
-To <dfn>create an Exception object</dfn> from a [=exception address=] |exnAddress| and a [=list=] of
-WebAssembly values |payload|, perform the following steps:
+To <dfn>create an Exception object</dfn> from a [=exception address=] |exnAddress|, perform the following steps:
 
 1. Let |map| be the [=surrounding agent=]'s associated [=Exception object cache=].
 1. If |map|[|exnAddress|] [=map/exists=],
@@ -1320,6 +1320,7 @@ constructor steps are:
 The <dfn method for="Exception">getArg(|index|)</dfn> method steps are:
 (XXX maybe rename this method? exns don't really have 'args' the way func types do and also for backward compatibility)
 
+1. Let |store| be the [=surrounding agent=]'s [=associated store=].
 1. Let (|tagaddr|, |payload|) be [=exn_read=](|store|, **this**.\[[Address]]).
 1. Assert: |tagaddr| is equal to **this**.\[[Type]].
 1. If |index| ≥ |payload|'s [=list/size=],

From 5b8380ad9c60ac0f239885ba7164e333569e0480 Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Wed, 3 Apr 2024 17:00:01 -0700
Subject: [PATCH 14/20] address comments

---
 document/js-api/index.bs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/document/js-api/index.bs b/document/js-api/index.bs
index 60702057d..050be8b1d 100644
--- a/document/js-api/index.bs
+++ b/document/js-api/index.bs
@@ -1266,6 +1266,7 @@ interface Exception {
 An {{Exception}} value represents an exception.
 
 <div algorithm>
+
 To <dfn>initialize an Exception object</dfn> |exn| from an [=Exception address=] |exnAddress|, perform the following steps:
 
 1. Let |map| be the [=surrounding agent=]'s associated [=Exception object cache=].
@@ -1308,6 +1309,7 @@ constructor steps are:
 1. [=list/iterate|For each=] |value| and |resultType| of |payload| and |types|, paired linearly,
     1. [=list/Append=] ? [=ToWebAssemblyValue=](|value|, |resultType|) to |wasmPayload|.
 1. Let (|store|, |exceptionAddr|) be [=exn_alloc=](|store|, |exceptionTag|.\[[Address]], |wasmPayload|)
+1. Set the [=surrounding agent=]'s [=associated store=] to |store|.
 1. [=initialize an Exception object|Initialize=] **this** from |exceptionAddr|.
 1. If |options|["traceStack"] is true,
     1. Set **this**.\[[Stack]] to either a {{DOMString}} representation of the current call stack or undefined.

From 4d03423cc3f256e3b61b473e182ddcfac7df3703 Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Thu, 4 Apr 2024 14:42:45 -0700
Subject: [PATCH 15/20] remove Tag parameter from getArg

---
 document/js-api/index.bs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/document/js-api/index.bs b/document/js-api/index.bs
index 050be8b1d..259325a0c 100644
--- a/document/js-api/index.bs
+++ b/document/js-api/index.bs
@@ -1257,7 +1257,7 @@ dictionary ExceptionOptions {
 [LegacyNamespace=WebAssembly, Exposed=(Window,Worker,Worklet)]
 interface Exception {
   constructor(Tag exceptionTag, sequence&lt;any> payload, optional ExceptionOptions options = {});
-  any getArg(Tag exceptionTag, [EnforceRange] unsigned long index);
+  any getArg([EnforceRange] unsigned long index);
   boolean is(Tag exceptionTag);
   readonly attribute (DOMString or undefined) stack;
 };
@@ -1320,7 +1320,6 @@ constructor steps are:
 <div algorithm>
 
 The <dfn method for="Exception">getArg(|index|)</dfn> method steps are:
-(XXX maybe rename this method? exns don't really have 'args' the way func types do and also for backward compatibility)
 
 1. Let |store| be the [=surrounding agent=]'s [=associated store=].
 1. Let (|tagaddr|, |payload|) be [=exn_read=](|store|, **this**.\[[Address]]).

From d073cfe3870dea38430ca97b938fed23ce52aa1f Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Thu, 4 Apr 2024 15:36:28 -0700
Subject: [PATCH 16/20] remove 2 more spurious references to webassembly throw

---
 document/js-api/index.bs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/document/js-api/index.bs b/document/js-api/index.bs
index 259325a0c..8e9b89423 100644
--- a/document/js-api/index.bs
+++ b/document/js-api/index.bs
@@ -813,7 +813,7 @@ Each {{Table}} object has a \[[Table]] internal slot, which is a [=table address
     1. Let |store| be the [=surrounding agent=]'s [=associated store=].
     1. Let (<var ignore>limits</var>, |elementType|) be [=table_type=](|store|, |tableaddr|).
     1. If |elementType| is [=exnref=],
-        1. [=Throw=] a {{TypeError}} exception.
+        1. Throw a {{TypeError}} exception.
     1. Let |result| be [=table_read=](|store|, |tableaddr|, |index|).
     1. If |result| is [=error=], throw a {{RangeError}} exception.
     1. Return [=ToJSValue=](|result|).
@@ -825,7 +825,7 @@ Each {{Table}} object has a \[[Table]] internal slot, which is a [=table address
     1. Let |store| be the [=surrounding agent=]'s [=associated store=].
     1. Let (<var ignore>limits</var>, |elementType|) be [=table_type=](|store|, |tableaddr|).
     1. If |elementType| is [=exnref=],
-        1. [=Throw=] a {{TypeError}} exception.
+        1. Throw a {{TypeError}} exception.
     1. If |value| is missing,
         1. Let |ref| be [=DefaultValue=](|elementType|).
     1. Otherwise,

From b6a79f9118d2d01f5d226e85731a6eb7ec552350 Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Thu, 4 Apr 2024 17:38:36 -0700
Subject: [PATCH 17/20] more properly allocate the JS exception tag, and
 wrap/unwrap JS exceptions.

Wasm throwing is still not properly defined.
---
 document/js-api/index.bs | 54 ++++++++++++++++++++++++++--------------
 1 file changed, 36 insertions(+), 18 deletions(-)

diff --git a/document/js-api/index.bs b/document/js-api/index.bs
index 8e9b89423..6b30c375f 100644
--- a/document/js-api/index.bs
+++ b/document/js-api/index.bs
@@ -102,6 +102,8 @@ urlPrefix: https://webassembly.github.io/exception-handling/core/; spec: WebAsse
     text: global address; url: exec/runtime.html#syntax-globaladdr
     text: extern address; url: exec/runtime.html#syntax-externaddr
     text: tag address; url: exec/runtime.html#syntax-tagaddr
+    text: tag_alloc; url: appendix/embedding.html#embed-tag-alloc
+    text: tag_type; url: appendix/embedding.html#embed-tag-type
     text: exception address; url: exec/runtime.html#syntax-exnaddr
     text: exn_alloc; url: appendix/embedding.html#embed-exn-alloc
     text: exn_read; url: appendix/embedding.html#embed-exn-read
@@ -1020,8 +1022,13 @@ This slot holds a [=function address=] relative to the [=surrounding agent=]'s [
     1. Set the [=surrounding agent=]'s [=associated store=] to |store|.
     1. If |ret| is [=error=], throw an exception. This exception should be a WebAssembly {{RuntimeError}} exception, unless otherwise indicated by <a href="#errors">the WebAssembly error mapping</a>.
     1. If |ret| is [=THROW=] [=ref.exn=] |exnaddr|, then
-        1. Let |exception| be [=create an Exception object|a new Exception=] created from |exnaddr|.
-        1. Throw |exception|.
+        1. Let (|tagaddr|, |payload|) be [=exn_read=](|store|, |exnaddr|).
+        1. Let |jsTagAddr| be the result of [=get the JavaScript exception tag |getting the JavaScript exception tag=].
+        1. If |tagaddr| is equal to |jsTagAddr|,
+            1. Throw the result of [=retrieving an extern value=] from |payload|[0].
+        1. Otherwise,
+            1. Let |exception| be [=create an Exception object|a new Exception=] created from |exnaddr|.
+            1. Throw |exception|.
     1. Let |outArity| be the [=list/size=] of |ret|.
     1. If |outArity| is 0, return undefined.
     1. Otherwise, if |outArity| is 1, return [=ToJSValue=](|ret|[0]).
@@ -1078,11 +1085,13 @@ Note: Exported Functions do not have a \[[Construct]] method and thus it is not
             1. If |v| [=implements=] {{Exception}},
                 1. Let |type| be |v|.\[[Type]].
                 1. Let |payload| be |v|.\[[Payload]].
+                1. Let |address| be |v|.\[[Address]].
+                1. [=WebAssembly/Throw=] with |address|.
             1. Otherwise,
-                1. Let |type| be the [=JavaScript exception tag=].
-                1. Let |payload| be « ».
-            1. Let |opaqueData| be [=ToWebAssemblyValue=](|v|, [=externref=])
-            1. [=WebAssembly/Throw=] with |type|, |payload| and |opaqueData|.
+                1. Let |type| be the result of [=get the JavaScript exception tag |getting the JavaScript exception tag=].
+                1. Let |payload| be [=ToWebAssemblyValue=](|v|, [=externref=]).
+                1. Let (|store|, |address|) be [=exn_alloc=](|store|, |type|, « |payload| »).
+            1. [=WebAssembly/Throw=] with |address|.
         1. Otherwise, return |result|.\[[Value]].
     1. Let |store| be the [=surrounding agent=]'s [=associated store=].
     1. Let (|store|, |funcaddr|) be [=func_alloc=](|store|, |functype|, |hostfunc|).
@@ -1173,10 +1182,6 @@ The algorithm <dfn>ToWebAssemblyValue</dfn>(|v|, |type|) coerces a JavaScript va
 
 <h3 id="tags">Tags</h3>
 
-The <dfn>tag_alloc</dfn>(|store|, |parameters|) algorithm creates a new [=tag address=] for |parameters| in |store| and returns the updated store and the [=tag address=].
-
-The <dfn>tag_parameters</dfn>(|store|, |tagAddress|) algorithm returns the [=list=] of types for |tagAddress| in |store|.
-
 <h4 id="exceptions-types">Exception types</h4>
 
 <pre class="idl">
@@ -1237,7 +1242,7 @@ The <dfn constructor for="Tag" lt="Tag(type)">new Tag(|type|)</dfn> constructor
 The <dfn method for="Tag">type()</dfn> method steps are:
 
 1. Let |store| be the [=surrounding agent=]'s [=associated store=].
-1. Let |parameters| be [=tag_parameters=](|store|, **this**.\[[Address]]).
+1. Let [|parameters|] → [] be [=tag_type=](|store|, **this**.\[[Address]]).
 1. Let |idlParameters| be «».
 1. [=list/iterate|For each=] |type| of |parameters|,
     1. [=list/Append=] [$FromValueType$](|type|) to |idlParameters|.
@@ -1302,7 +1307,7 @@ lt="Exception(exceptionTag, payload, options)">new Exception(|exceptionTag|, |pa
 constructor steps are:
 
 1. Let |store| be the [=surrounding agent=]'s [=associated store=].
-1. Let |types| be [=tag_parameters=](|store|, |exceptionTag|.\[[Address]]).
+1. Let [|types|] → [] be [=tag_type=](|store|, |exceptionTag|.\[[Address]]).
 1. If |types|'s [=list/size=] is not |payload|'s [=list/size=],
     1. Throw a {{TypeError}}.
 1. Let |wasmPayload| be « ».
@@ -1350,18 +1355,31 @@ The <dfn attribute for="Exception">stack</dfn> getter steps are:
 
 <h4 id="js-exceptions">JavaScript exceptions</h4>
 
-The <dfn>JavaScript exception tag</dfn> is a [=tag address=] reserved by this
-specification to distinguish exceptions originating from JavaScript.
+The <dfn>JavaScript exception tag</dfn> is a [=tag address=] associated with
+the surrounding agent. It is allocated in the agent's [=associated store=] on
+first use and cached. It always has the tag type « [=externref=] » → « ».
+
+
+<div algorithm>
+
+To <dfn>get the JavaScript exception tag</dfn>, perform the following steps:
 
-For any [=associated store=] |store|, the result of
-[=tag_parameters=](|store|, [=JavaScript exception tag=]) must be « ».
+    1. If the [=surrounding agent=]'s associated [=JavaScript exception tag=] has been initialized,
+        1. return the [=surrounding agent=]'s associated [=JavaScript exception tag=]
+    1. Let |store| be the [=surrounding agent=]'s [=associated store=].
+    1. Let (|store|, |tagAddress|) be [=tag_alloc=](|store|, « [=externref=] » → « »).
+    1. Set the current agent's [=associated store=] to |store|.
+    1. Set the current agent's associated [=JavaScript exception tag=] to |tagAddress|.
+    1. return |tagAddress|.
+
+</div>
 
 <div algorithm>
 
-To <dfn for=WebAssembly>throw</dfn> with a [=tag address=] |type|, a matching [=list=] of WebAssembly values |payload|, and an [=externref=] |opaqueData|, perform the following steps:
+To <dfn for=WebAssembly>throw</dfn> with a [=tag address=] |type|, a matching [=list=] of WebAssembly values |payload|, and an [=exception address=] |address|, perform the following steps:
 
 1. Unwind the stack until reaching the *catching try block* given |type|.
-1. Invoke the catch block with |payload| and |opaqueData|.
+1. Invoke the catch block with |payload| and |address|.
 
 Note: This algorithm is expected to be moved into the core specification.
 

From 51338d7e32f1129a9409e6f7c3d9436d5ff14b51 Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Fri, 5 Apr 2024 11:37:42 -0700
Subject: [PATCH 18/20] apply review comments

---
 document/js-api/index.bs | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/document/js-api/index.bs b/document/js-api/index.bs
index 6b30c375f..1b06f0dc2 100644
--- a/document/js-api/index.bs
+++ b/document/js-api/index.bs
@@ -101,6 +101,7 @@ urlPrefix: https://webassembly.github.io/exception-handling/core/; spec: WebAsse
     text: memory address; url: exec/runtime.html#syntax-memaddr
     text: global address; url: exec/runtime.html#syntax-globaladdr
     text: extern address; url: exec/runtime.html#syntax-externaddr
+    text: tag type; url: syntax/types.html#syntax-tagtype
     text: tag address; url: exec/runtime.html#syntax-tagaddr
     text: tag_alloc; url: appendix/embedding.html#embed-tag-alloc
     text: tag_type; url: appendix/embedding.html#embed-tag-type
@@ -1080,20 +1081,18 @@ Note: Exported Functions do not have a \[[Construct]] method and thus it is not
         1. [=Clean up after running a callback=] with |stored settings|.
         1. [=Clean up after running script=] with |relevant settings|.
         1. Assert: |result|.\[[Type]] is <emu-const>throw</emu-const> or <emu-const>normal</emu-const>.
+        1. Let |store| be the [=surrounding agent=]'s [=associated store=].
         1. If |result|.\[[Type]] is <emu-const>throw</emu-const>, then:
             1. Let |v| be |result|.\[[Value]].
             1. If |v| [=implements=] {{Exception}},
-                1. Let |type| be |v|.\[[Type]].
-                1. Let |payload| be |v|.\[[Payload]].
                 1. Let |address| be |v|.\[[Address]].
-                1. [=WebAssembly/Throw=] with |address|.
             1. Otherwise,
                 1. Let |type| be the result of [=get the JavaScript exception tag |getting the JavaScript exception tag=].
-                1. Let |payload| be [=ToWebAssemblyValue=](|v|, [=externref=]).
+                1. Let |payload| be [=!=] [=ToWebAssemblyValue=](|v|, [=externref=]).
                 1. Let (|store|, |address|) be [=exn_alloc=](|store|, |type|, « |payload| »).
+                1. Set the [=surrounding agent=]'s [=associated store=] to |store|.
             1. [=WebAssembly/Throw=] with |address|.
         1. Otherwise, return |result|.\[[Value]].
-    1. Let |store| be the [=surrounding agent=]'s [=associated store=].
     1. Let (|store|, |funcaddr|) be [=func_alloc=](|store|, |functype|, |hostfunc|).
     1. Set the [=surrounding agent=]'s [=associated store=] to |store|.
     1. Return |funcaddr|.
@@ -1312,7 +1311,7 @@ constructor steps are:
     1. Throw a {{TypeError}}.
 1. Let |wasmPayload| be « ».
 1. [=list/iterate|For each=] |value| and |resultType| of |payload| and |types|, paired linearly,
-    1. [=list/Append=] ? [=ToWebAssemblyValue=](|value|, |resultType|) to |wasmPayload|.
+    1. [=list/Append=] [=?=] [=ToWebAssemblyValue=](|value|, |resultType|) to |wasmPayload|.
 1. Let (|store|, |exceptionAddr|) be [=exn_alloc=](|store|, |exceptionTag|.\[[Address]], |wasmPayload|)
 1. Set the [=surrounding agent=]'s [=associated store=] to |store|.
 1. [=initialize an Exception object|Initialize=] **this** from |exceptionAddr|.
@@ -1357,7 +1356,7 @@ The <dfn attribute for="Exception">stack</dfn> getter steps are:
 
 The <dfn>JavaScript exception tag</dfn> is a [=tag address=] associated with
 the surrounding agent. It is allocated in the agent's [=associated store=] on
-first use and cached. It always has the tag type « [=externref=] » → « ».
+first use and cached. It always has the [=tag type=] « [=externref=] » → « ».
 
 
 <div algorithm>
@@ -1376,7 +1375,7 @@ To <dfn>get the JavaScript exception tag</dfn>, perform the following steps:
 
 <div algorithm>
 
-To <dfn for=WebAssembly>throw</dfn> with a [=tag address=] |type|, a matching [=list=] of WebAssembly values |payload|, and an [=exception address=] |address|, perform the following steps:
+To <dfn for=WebAssembly>throw</dfn> with an [=exception address=] |address|, perform the following steps:
 
 1. Unwind the stack until reaching the *catching try block* given |type|.
 1. Invoke the catch block with |payload| and |address|.

From dfdd0b938077b318f4d880e2520a2fa342c2803d Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Fri, 5 Apr 2024 11:52:18 -0700
Subject: [PATCH 19/20] inline throwing into 'create a host function' and
 define in terms of throw_ref

---
 document/js-api/index.bs | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/document/js-api/index.bs b/document/js-api/index.bs
index 1b06f0dc2..021e3def7 100644
--- a/document/js-api/index.bs
+++ b/document/js-api/index.bs
@@ -101,13 +101,13 @@ urlPrefix: https://webassembly.github.io/exception-handling/core/; spec: WebAsse
     text: memory address; url: exec/runtime.html#syntax-memaddr
     text: global address; url: exec/runtime.html#syntax-globaladdr
     text: extern address; url: exec/runtime.html#syntax-externaddr
-    text: tag type; url: syntax/types.html#syntax-tagtype
     text: tag address; url: exec/runtime.html#syntax-tagaddr
     text: tag_alloc; url: appendix/embedding.html#embed-tag-alloc
     text: tag_type; url: appendix/embedding.html#embed-tag-type
     text: exception address; url: exec/runtime.html#syntax-exnaddr
     text: exn_alloc; url: appendix/embedding.html#embed-exn-alloc
     text: exn_read; url: appendix/embedding.html#embed-exn-read
+    text: tag type; url: syntax/types.html#syntax-tagtype
     url: syntax/types.html#syntax-numtype
         text: i32
         text: i64
@@ -152,6 +152,7 @@ urlPrefix: https://webassembly.github.io/exception-handling/core/; spec: WebAsse
     text: address; url: exec/runtime.html#addresses
     text: signed_32; url: exec/numerics.html#aux-signed
     text: memory.grow; url: exec/instructions.html#exec-memory-grow
+    text: throw_ref; url: exec/instructions.html#exec-throw-ref
     text: current frame; url: exec/conventions.html#exec-notation-textual
     text: module; for: frame; url: exec/runtime.html#syntax-frame
     text: memaddrs; for: moduleinst; url: exec/runtime.html#syntax-moduleinst
@@ -1091,7 +1092,7 @@ Note: Exported Functions do not have a \[[Construct]] method and thus it is not
                 1. Let |payload| be [=!=] [=ToWebAssemblyValue=](|v|, [=externref=]).
                 1. Let (|store|, |address|) be [=exn_alloc=](|store|, |type|, « |payload| »).
                 1. Set the [=surrounding agent=]'s [=associated store=] to |store|.
-            1. [=WebAssembly/Throw=] with |address|.
+            1. Execute the wasm instructions ([=ref.exn=] |address|) ([=throw_ref=])
         1. Otherwise, return |result|.\[[Value]].
     1. Let (|store|, |funcaddr|) be [=func_alloc=](|store|, |functype|, |hostfunc|).
     1. Set the [=surrounding agent=]'s [=associated store=] to |store|.
@@ -1373,17 +1374,6 @@ To <dfn>get the JavaScript exception tag</dfn>, perform the following steps:
 
 </div>
 
-<div algorithm>
-
-To <dfn for=WebAssembly>throw</dfn> with an [=exception address=] |address|, perform the following steps:
-
-1. Unwind the stack until reaching the *catching try block* given |type|.
-1. Invoke the catch block with |payload| and |address|.
-
-Note: This algorithm is expected to be moved into the core specification.
-
-</div>
-
 <h3 id="error-objects">Error Objects</h3>
 
 WebAssembly defines the following Error classes: <dfn exception>CompileError</dfn>, <dfn exception>LinkError</dfn>, and <dfn exception>RuntimeError</dfn>.

From 624bcca8c553764a879c643543168114156744e2 Mon Sep 17 00:00:00 2001
From: Derek Schuff <dschuff@chromium.org>
Date: Tue, 9 Apr 2024 14:10:35 -0700
Subject: [PATCH 20/20] apply suggestion

---
 document/js-api/index.bs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/document/js-api/index.bs b/document/js-api/index.bs
index 021e3def7..ba25a4cc5 100644
--- a/document/js-api/index.bs
+++ b/document/js-api/index.bs
@@ -1092,7 +1092,7 @@ Note: Exported Functions do not have a \[[Construct]] method and thus it is not
                 1. Let |payload| be [=!=] [=ToWebAssemblyValue=](|v|, [=externref=]).
                 1. Let (|store|, |address|) be [=exn_alloc=](|store|, |type|, « |payload| »).
                 1. Set the [=surrounding agent=]'s [=associated store=] to |store|.
-            1. Execute the wasm instructions ([=ref.exn=] |address|) ([=throw_ref=])
+            1. Execute the WebAssembly instructions ([=ref.exn=] |address|) ([=throw_ref=]).
         1. Otherwise, return |result|.\[[Value]].
     1. Let (|store|, |funcaddr|) be [=func_alloc=](|store|, |functype|, |hostfunc|).
     1. Set the [=surrounding agent=]'s [=associated store=] to |store|.