compiler: add builtinInvoke for subkernel raising functions

artiq/compiler/ir.py

@@ -1047,6 +1047,42 @@ class Builtin(Instruction):
     def opcode(self):
         return "builtin({})".format(self.op)
 
+class BuiltinInvoke(Terminator):
+    """
+    A builtin operation which can raise exceptions.
+
+    :ivar op: (string) operation name
+    """
+
+    """
+    :param op: (string) operation name
+    :param normal: (:class:`BasicBlock`) normal target
+    :param exn: (:class:`BasicBlock`) exceptional target
+    """
+    def __init__(self, op, operands, typ, normal, exn, name=None):
+        assert isinstance(op, str)
+        for operand in operands: assert isinstance(operand, Value)
+        assert isinstance(normal, BasicBlock)
+        assert isinstance(exn, BasicBlock)
+        if name is None:
+            name = "BLTINV.{}".format(op)
+        super().__init__(operands + [normal, exn], typ, name)
+        self.op = op
+
+    def copy(self, mapper):
+        self_copy = super().copy(mapper)
+        self_copy.op = self.op
+        return self_copy
+
+    def normal_target(self):
+        return self.operands[-2]
+
+    def exception_target(self):
+        return self.operands[-1]
+
+    def opcode(self):
+        return "builtinInvokable({})".format(self.op)
+
 class Closure(Instruction):
     """
     A closure creation operation.

artiq/compiler/transforms/artiq_ir_generator.py

@@ -2544,10 +2544,22 @@ class ARTIQIRGenerator(algorithm.Visitor):
                 fn = types.get_method_function(fn)
             sid = ir.Constant(fn.sid, builtins.TInt32())
             if not builtins.is_none(fn.ret):
-                ret = self.append(ir.Builtin("subkernel_retrieve_return", [sid, timeout], fn.ret))
+                if self.unwind_target is None:
+                    ret = self.append(ir.Builtin("subkernel_retrieve_return", [sid, timeout], fn.ret))
+                else:
+                    after_invoke = self.add_block("invoke")
+                    ret = self.append(ir.BuiltinInvoke("subkernel_retrieve_return", [sid, timeout], 
+                                                       fn.ret, after_invoke, self.unwind_target))
+                    self.current_block = after_invoke
             else:
                 ret = ir.Constant(None, builtins.TNone())
-            self.append(ir.Builtin("subkernel_await_finish", [sid, timeout], builtins.TNone()))
+            if self.unwind_target is None:
+                self.append(ir.Builtin("subkernel_await_finish", [sid, timeout], builtins.TNone()))
+            else:
+                after_invoke = self.add_block("invoke")
+                self.append(ir.BuiltinInvoke("subkernel_await_finish", [sid, timeout], 
+                                                builtins.TNone(), after_invoke, self.unwind_target))
+                self.current_block = after_invoke
             return ret
         elif types.is_builtin(typ, "subkernel_preload"):
             if len(node.args) == 1 and len(node.keywords) == 0:
@@ -2594,7 +2606,14 @@ class ARTIQIRGenerator(algorithm.Visitor):
                     {"name": name, "recv": vartype, "send": msg.value_type},
                     node.loc)
                 self.engine.process(diag)
-            return self.append(ir.Builtin("subkernel_recv", [msg_id, timeout], vartype))
+            if self.unwind_target is None:
+                ret = self.append(ir.Builtin("subkernel_recv", [msg_id, timeout], vartype))
+            else:
+                after_invoke = self.add_block("invoke")
+                ret = self.append(ir.BuiltinInvoke("subkernel_recv", [msg_id, timeout], 
+                                                   vartype, after_invoke, self.unwind_target))
+                self.current_block = after_invoke
+            return ret
         elif types.is_exn_constructor(typ):
             return self.alloc_exn(node.type, *[self.visit(arg_node) for arg_node in node.args])
         elif types.is_constructor(typ):
@@ -2946,7 +2965,7 @@ class ARTIQIRGenerator(algorithm.Visitor):
                 format_string += ")"
             elif builtins.is_exception(value.type):
                 # message may not be an actual string...
-                # so we cannot really print it
+                # so we cannot really print itInvoke
                 name    = self.append(ir.GetAttr(value, "#__name__"))
                 param1  = self.append(ir.GetAttr(value, "#__param0__"))
                 param2  = self.append(ir.GetAttr(value, "#__param1__"))

artiq/compiler/transforms/llvm_ir_generator.py

@@ -1437,6 +1437,44 @@ class LLVMIRGenerator:
         else:
             assert False
 
+    def process_BuiltinInvoke(self, insn):
+        llnormalblock = self.map(insn.normal_target())
+        llunwindblock = self.map(insn.exception_target())
+        if insn.op == "subkernel_retrieve_return":
+            llsid = self.map(insn.operands[0])
+            lltimeout = self.map(insn.operands[1])
+            lltagptr = self._build_subkernel_tags([insn.type])
+            llheadu = self.llbuilder.append_basic_block(name="subkernel.await.unwind")
+            self.llbuilder.invoke(self.llbuiltin("subkernel_await_message"), 
+                                  [llsid, lltimeout, lltagptr, ll.Constant(lli8, 1), ll.Constant(lli8, 1)],
+                                  llheadu, llunwindblock,
+                                  name="subkernel.await.message")
+            self.llbuilder.position_at_end(llheadu)
+            llstackptr = self.llbuilder.call(self.llbuiltin("llvm.stacksave"), [],
+                                             name="subkernel.arg.stack")
+            return self._build_rpc_recv(insn.type, llstackptr, llnormalblock, llunwindblock)
+        elif insn.op == "subkernel_await_finish":
+            llsid = self.map(insn.operands[0])
+            lltimeout = self.map(insn.operands[1])
+            return self.llbuilder.invoke(self.llbuiltin("subkernel_await_finish"), [llsid, lltimeout],
+                                         llnormalblock, llunwindblock,
+                                         name="subkernel.await.finish")
+        elif insn.op == "subkernel_recv":
+            llmsgid = self.map(insn.operands[0])
+            lltimeout = self.map(insn.operands[1])
+            lltagptr = self._build_subkernel_tags([insn.type])
+            llheadu = self.llbuilder.append_basic_block(name="subkernel.await.unwind")
+            self.llbuilder.invoke(self.llbuiltin("subkernel_await_message"), 
+                                  [llmsgid, lltimeout, lltagptr, ll.Constant(lli8, 1), ll.Constant(lli8, 1)],
+                                  llheadu, llunwindblock,
+                                  name="subkernel.await.message")
+            self.llbuilder.position_at_end(llheadu)
+            llstackptr = self.llbuilder.call(self.llbuiltin("llvm.stacksave"), [],
+                                             name="subkernel.arg.stack")
+            return self._build_rpc_recv(insn.type, llstackptr, llnormalblock, llunwindblock)
+        else:
+            assert False
+
     def process_SubkernelAwaitArgs(self, insn):
         llmin = self.map(insn.operands[0])
         llmax = self.map(insn.operands[1])

artiq/firmware/runtime/kernel.rs

@@ -278,8 +278,15 @@ pub mod subkernel {
     {
         let mut reader = Cursor::new(buffer);
 
-        let _sync = reader.read_u32()?;
+        let mut byte = reader.read_u8()?;
-        let _9 = reader.read_u8()?;
+        // to sync
+        while byte != 0x5a {
+            byte = reader.read_u8()?;
+        }
+        // skip sync bytes, 0x09 indicates exception
+        while byte != 0x09 {
+            byte = reader.read_u8()?;
+        }
         let _len = reader.read_u32()?;
         // ignore the remaining exceptions, stack traces etc. - unwinding from another device would be unwise anyway
         Ok(Exception {