Merge pull request WebAssembly#416 from WebAssembly/array-copy-getu

Update array.copy semantics to handle packed types

document/core/exec/instructions.rst

@@ -1120,61 +1120,67 @@ Reference Instructions
 :math:`\ARRAYCOPY~x~y`
 ......................
 
-.. todo:: Handle packed fields correctly via array.get_u instead of array.get
+1. Assert: due to :ref:`validation <valid-array.copy>`, the :ref:`defined type <syntax-deftype>` :math:`F.\AMODULE.\MITYPES[y]` exists.
 
-1. Assert: due to :ref:`validation <valid-array.copy>`, a :ref:`value <syntax-val>` of :ref:`type <syntax-valtype>` :math:`\I32` is on the top of the stack.
+2. Let :math:`\deftype` be the :ref:`defined type <syntax-deftype>` :math:`F.\AMODULE.\MITYPES[y]`.
 
-2. Pop the value :math:`n` from the stack.
-
-3. Assert: due to :ref:`validation <valid-array.copy>`, a :ref:`value <syntax-val>` of :ref:`type <syntax-valtype>` :math:`\I32` is on the top of the stack.
+3. Assert: due to :ref:`validation <valid-array.copy>`, the :ref:`expansion <aux-expand-deftype>` of :math:`\deftype` is an :ref:`array type <syntax-arraytype>`.
 
-4. Pop the value :math:`s` from the stack.
+4. Let :math:`\TARRAY~\mut~\X{st}` be the :ref:`expanded <aux-expand-deftype>` :ref:`array type <syntax-arraytype>` :math:`\deftype`.
 
-5. Assert: due to :ref:`validation <valid-array.copy>`, a :ref:`value <syntax-val>` of :ref:`type <syntax-valtype>` :math:`(\REF~\NULL~y)` is on the top of the stack.
+5. Assert: due to :ref:`validation <valid-array.copy>`, a :ref:`value <syntax-val>` of :ref:`type <syntax-valtype>` :math:`\I32` is on the top of the stack.
 
-6. Pop the value :math:`\reff_2` from the stack.
+6. Pop the value :math:`\I32.\CONST~n` from the stack.
 
 7. Assert: due to :ref:`validation <valid-array.copy>`, a :ref:`value <syntax-val>` of :ref:`type <syntax-valtype>` :math:`\I32` is on the top of the stack.
 
-8. Pop the value :math:`d` from the stack.
+8. Pop the value :math:`\I32.\CONST~s` from the stack.
+
+9. Assert: due to :ref:`validation <valid-array.copy>`, a :ref:`value <syntax-val>` of :ref:`type <syntax-valtype>` :math:`(\REF~\NULL~y)` is on the top of the stack.
+
+10. Pop the value :math:`\reff_2` from the stack.
+
+11. Assert: due to :ref:`validation <valid-array.copy>`, a :ref:`value <syntax-val>` of :ref:`type <syntax-valtype>` :math:`\I32` is on the top of the stack.
+
+12. Pop the value :math:`\I32.\CONST~d` from the stack.
 
-9. Assert: due to :ref:`validation <valid-array.copy>`, a :ref:`value <syntax-val>` of :ref:`type <syntax-valtype>` :math:`(\REF~\NULL~x)` is on the top of the stack.
+13. Assert: due to :ref:`validation <valid-array.copy>`, a :ref:`value <syntax-val>` of :ref:`type <syntax-valtype>` :math:`(\REF~\NULL~x)` is on the top of the stack.
 
-10. Pop the value :math:`\reff_1` from the stack.
+14. Pop the value :math:`\reff_1` from the stack.
 
-11. If :math:`\reff_1` is :math:`\REFNULL~t`, then:
+15. If :math:`\reff_1` is :math:`\REFNULL~t`, then:
 
    a. Trap.
 
-12. Assert: due to :ref:`validation <valid-array.copy>`, :math:`\reff_1` is an :ref:`array reference <syntax-ref.array>`.
+16. Assert: due to :ref:`validation <valid-array.copy>`, :math:`\reff_1` is an :ref:`array reference <syntax-ref.array>`.
 
-13. Let :math:`\REFARRAYADDR~a_1` be the reference value :math:`\reff_1`.
+17. Let :math:`\REFARRAYADDR~a_1` be the reference value :math:`\reff_1`.
 
-14. If :math:`\reff_2` is :math:`\REFNULL~t`, then:
+18. If :math:`\reff_2` is :math:`\REFNULL~t`, then:
 
    a. Trap.
 
-15. Assert: due to :ref:`validation <valid-array.copy>`, :math:`\reff_2` is an :ref:`array reference <syntax-ref.array>`.
+19. Assert: due to :ref:`validation <valid-array.copy>`, :math:`\reff_2` is an :ref:`array reference <syntax-ref.array>`.
 
-16. Let :math:`\REFARRAYADDR~a_2` be the reference value :math:`\reff_2`.
+20. Let :math:`\REFARRAYADDR~a_2` be the reference value :math:`\reff_2`.
 
-17. Assert: due to :ref:`validation <valid-array.copy>`, the :ref:`array instance <syntax-arrayinst>` :math:`S.\SARRAYS[a_1]` exists.
+21. Assert: due to :ref:`validation <valid-array.copy>`, the :ref:`array instance <syntax-arrayinst>` :math:`S.\SARRAYS[a_1]` exists.
 
-18. Assert: due to :ref:`validation <valid-array.copy>`, the :ref:`array instance <syntax-arrayinst>` :math:`S.\SARRAYS[a_2]` exists.
+22. Assert: due to :ref:`validation <valid-array.copy>`, the :ref:`array instance <syntax-arrayinst>` :math:`S.\SARRAYS[a_2]` exists.
 
-19. If :math:`d + n` is larger than or equal to the length of :math:`S.\SARRAYS[a_1].\AIFIELDS`, then:
+23. If :math:`d + n` is larger than or equal to the length of :math:`S.\SARRAYS[a_1].\AIFIELDS`, then:
 
     a. Trap.
 
-20. If :math:`s + n` is larger than or equal to the length of :math:`S.\SARRAYS[a_2].\AIFIELDS`, then:
+24. If :math:`s + n` is larger than or equal to the length of :math:`S.\SARRAYS[a_2].\AIFIELDS`, then:
 
     a. Trap.
 
-21. If :math:`n = 0`, then:
+25. If :math:`n = 0`, then:
 
     a. Return.
 
-22. If :math:`d \leq s`, then:
+26. If :math:`d \leq s`, then:
 
     a. Push the value :math:`\REFARRAYADDR~a_1` to the stack.
 
@@ -1184,7 +1190,7 @@ Reference Instructions
 
     d. Push the value :math:`\I32.\CONST~s` to the stack.
 
-    e. Execute the instruction :math:`\ARRAYGET~y`.
+    e. Execute :math:`\getfield(\X{st})`.
 
     f. Execute the instruction :math:`\ARRAYSET~x`.
 
@@ -1200,7 +1206,7 @@ Reference Instructions
 
     l. Push the value :math:`\I32.\CONST~(s+1)` to the stack.
 
-23. Else:
+27. Else:
 
     a. Push the value :math:`\REFARRAYADDR~a_1` to the stack.
 
@@ -1214,7 +1220,7 @@ Reference Instructions
 
     f. Push the value :math:`\I32.\CONST~(s+n-1)` to the stack.
 
-    g. Execute the instruction :math:`\ARRAYGET~y`.
+    g. Execute :math:`\getfield(\X{st})`.
 
     h. Execute the instruction :math:`\ARRAYSET~x`.
 
@@ -1226,9 +1232,9 @@ Reference Instructions
 
     l. Push the value :math:`\I32.\CONST~s` to the stack.
 
-24. Push the value :math:`\I32.\CONST~(n-1)` to the stack.
+28. Push the value :math:`\I32.\CONST~(n-1)` to the stack.
 
-25. Execute the instruction :math:`\ARRAYCOPY~x~y`.
+29. Execute the instruction :math:`\ARRAYCOPY~x~y`.
 
 .. math::
    ~\\[-1ex]
@@ -1248,30 +1254,40 @@ Reference Instructions
      \\ \quad S;
        \begin{array}[t]{@{}l@{}}
        (\REFARRAYADDR~a_1)~(\I32.\CONST~d) \\
-       (\REFARRAYADDR~a_2)~(\I32.\CONST~s)~(\ARRAYGET~y) \\
+       (\REFARRAYADDR~a_2)~(\I32.\CONST~s)~\getfield(\X{st}) \\
        (\ARRAYSET~x) \\
        (\REFARRAYADDR~a_1)~(\I32.\CONST~d+1)~(\REFARRAYADDR~a_2)~(\I32.\CONST~s+1)~(\I32.\CONST~n)~(\ARRAYCOPY~x~y) \\
        \end{array}
      \\ \qquad
-     (\otherwise, \iff d \leq s)
+     (\otherwise, \iff d \leq s \land F.\AMODULE.\MITYPES[x] = \TARRAY~\mut~\X{st}) \\
    \\[1ex]
    S; (\REFARRAYADDR~a_1)~(\I32.\CONST~d)~(\REFARRAYADDR~a_2)~(\I32.\CONST~s)~(\I32.\CONST~n+1)~(\ARRAYCOPY~x~y)
      \quad\stepto
      \\ \quad S;
        \begin{array}[t]{@{}l@{}}
        (\REFARRAYADDR~a_1)~(\I32.\CONST~d+n) \\
-       (\REFARRAYADDR~a_2)~(\I32.\CONST~s+n)~(\ARRAYGET~y) \\
+       (\REFARRAYADDR~a_2)~(\I32.\CONST~s+n)~\getfield(\X{st}) \\
        (\ARRAYSET~x) \\
        (\REFARRAYADDR~a_1)~(\I32.\CONST~d)~(\REFARRAYADDR~a_2)~(\I32.\CONST~s)~(\I32.\CONST~n)~(\ARRAYCOPY~x~y) \\
        \end{array}
      \\ \qquad
-     (\otherwise, \iff d > s)
+     (\otherwise, \iff d > s \land F.\AMODULE.\MITYPES[x] = \TARRAY~\mut~\X{st}) \\
    \\[1ex]
    S; (\REFNULL~t)~(\I32.\CONST~d)~\val~(\I32.\CONST~s)~(\I32.\CONST~n)~(\ARRAYCOPY~x~y) \quad\stepto\quad \TRAP
    \\[1ex]
    S; \val~(\I32.\CONST~d)~(\REFNULL~t)~(\I32.\CONST~s)~(\I32.\CONST~n)~(\ARRAYCOPY~x~y) \quad\stepto\quad \TRAP
    \end{array}
 
+Where:
+
+.. _aux-getfield:
+
+.. math::
+   \begin{array}{lll}
+   \getfield(\valtype) &=& \ARRAYGET \\
+   \getfield(\packedtype) &=& \ARRAYGETU \\
+   \end{array}
+
 
 .. _exec-array.init_data:
 

document/core/syntax/instructions.rst

@@ -541,7 +541,6 @@ The instructions |I31NEW| and :math:`\I31GET\K{\_}\sx` convert between type |I31
 
 The instructions |EXTERNINTERNALIZE| and |EXTERNEXTERNALIZE| allow lossless conversion between references represented as type :math:`(\REF~\NULL~\EXTERN)`| and as :math:`(\REF~\NULL~\ANY)`.
 
-
 .. index:: ! parametric instruction, value type
    pair: abstract syntax; instruction
 .. _syntax-instr-parametric:

document/core/util/macros.def

@@ -660,6 +660,11 @@
 .. |expr| mathdef:: \xref{syntax/instructions}{syntax-expr}{\X{expr}}
 
 
+.. Instructions, meta functions
+
+.. |getfield| mathdef:: \xref{exec/instructions}{aux-getfield}{\F{getfield}}
+
+
 
 .. Binary Format
 .. -------------