--- a/ipc/ipdl/ipdl/lower.py
+++ b/ipc/ipdl/ipdl/lower.py
@@ -4326,16 +4326,26 @@ class _GenerateProtocolActorCode(ipdl.as
         msgvar = self.msgvar
         itervar = self.itervar
         lenvar = ExprVar('length')
         ivar = ExprVar('i')
         eltipdltype = arraytype.basetype
         intype = _cxxConstRefType(arraytype, self.side)
         outtype = _cxxPtrToType(arraytype, self.side)
 
+        # We access elements directly in Read and Write to avoid array bounds
+        # checking.
+        directtype = _cxxBareType(arraytype.basetype, self.side)
+        if directtype.ptr:
+            typeinit = { 'ptrptr': 1 }
+        else:
+            typeinit = { 'ptr': 1 }
+        directtype = Type(directtype.name, **typeinit)
+        elemsvar = ExprVar('elems')
+
         write = MethodDefn(self.writeMethodDecl(intype, var))
         forwrite = StmtFor(init=ExprAssn(Decl(Type.UINT32, ivar.name),
                                          ExprLiteral.ZERO),
                            cond=ExprBinary(ivar, '<', lenvar),
                            update=ExprPrefixUnop(ivar, '++'))
         forwrite.addstmt(
             self.checkedWrite(eltipdltype, ExprIndex(var, ivar), msgvar,
                               sentinelKey=arraytype.name()))
@@ -4349,29 +4359,32 @@ class _GenerateProtocolActorCode(ipdl.as
 
         read = MethodDefn(self.readMethodDecl(outtype, var))
         favar = ExprVar('fa')
         forread = StmtFor(init=ExprAssn(Decl(Type.UINT32, ivar.name),
                                         ExprLiteral.ZERO),
                           cond=ExprBinary(ivar, '<', lenvar),
                           update=ExprPrefixUnop(ivar, '++'))
         forread.addstmt(
-            self.checkedRead(eltipdltype, ExprAddrOf(ExprIndex(favar, ivar)),
+            self.checkedRead(eltipdltype, ExprAddrOf(ExprIndex(elemsvar, ivar)),
                              msgvar, itervar, errfnRead,
                              '\'' + eltipdltype.name() + '[i]\'',
                              sentinelKey=arraytype.name()))
+        appendstmt = StmtDecl(Decl(directtype, elemsvar.name),
+                              init=ExprCall(ExprSelect(favar, '.', 'AppendElements'),
+                                            args=[ lenvar ]))
         read.addstmts([
             StmtDecl(Decl(_cxxArrayType(_cxxBareType(arraytype.basetype, self.side)), favar.name)),
             StmtDecl(Decl(Type.UINT32, lenvar.name)),
             self.checkedRead(None, ExprAddrOf(lenvar),
                              msgvar, itervar, errfnArrayLength,
                              [ arraytype.name() ],
                              sentinelKey=('length', arraytype.name())),
             Whitespace.NL,
-            StmtExpr(_callCxxArraySetLength(favar, lenvar)),
+            appendstmt,
             forread,
             StmtExpr(_callCxxSwapArrayElements(var, favar, '->')),
             StmtReturn.TRUE
         ])
 
         self.cls.addstmts([ write, Whitespace.NL, read, Whitespace.NL ])