Add tests for finally clause and reraising.

artiq/compiler/ir.py

@@ -979,15 +979,14 @@ class Raise(Terminator):
 
     """
     :param value: (:class:`Value`) exception value
-    :param exn: (:class:`BasicBlock`) exceptional target
+    :param exn: (:class:`BasicBlock` or None) exceptional target
     """
-    def __init__(self, value, exn=None, name=""):
+    def __init__(self, value=None, exn=None, name=""):
         assert isinstance(value, Value)
+        operands = [value]
         if exn is not None:
             assert isinstance(exn, BasicBlock)
-            operands = [value, exn]
-        else:
-            operands = [value]
+            operands.append(exn)
         super().__init__(operands, builtins.TNone(), name)
 
     def opcode(self):
@@ -1000,6 +999,28 @@ class Raise(Terminator):
         if len(self.operands) > 1:
             return self.operands[1]
 
+class Reraise(Terminator):
+    """
+    A reraise instruction.
+    """
+
+    """
+    :param exn: (:class:`BasicBlock` or None) exceptional target
+    """
+    def __init__(self, exn=None, name=""):
+        operands = []
+        if exn is not None:
+            assert isinstance(exn, BasicBlock)
+            operands.append(exn)
+        super().__init__(operands, builtins.TNone(), name)
+
+    def opcode(self):
+        return "reraise"
+
+    def exception_target(self):
+        if len(self.operands) > 0:
+            return self.operands[0]
+
 class Invoke(Terminator):
     """
     A function call operation that supports exception handling.
@@ -1051,12 +1072,18 @@ class LandingPad(Terminator):
         exception types corresponding to the basic block operands
     """
 
-    def __init__(self, name=""):
-        super().__init__([], builtins.TException(), name)
+    def __init__(self, cleanup, name=""):
+        super().__init__([cleanup], builtins.TException(), name)
         self.types = []
 
+    def opcode(self):
+        return "landingpad"
+
+    def cleanup(self):
+        return self.operands[0]
+
     def clauses(self):
-        return zip(self.operands, self.types)
+        return zip(self.operands[1:], self.types)
 
     def add_clause(self, target, typ):
         assert isinstance(target, BasicBlock)
@@ -1065,14 +1092,11 @@ class LandingPad(Terminator):
         self.types.append(typ.find() if typ is not None else None)
         target.uses.add(self)
 
-    def opcode(self):
-        return "landingpad"
-
     def _operands_as_string(self):
         table = []
-        for typ, target in zip(self.types, self.operands):
+        for target, typ in self.clauses():
             if typ is None:
                 table.append("... => {}".format(target.as_operand()))
             else:
                 table.append("{} => {}".format(types.TypePrinter().name(typ), target.as_operand()))
-        return "[{}]".format(", ".join(table))
+        return "cleanup {}, [{}]".format(self.cleanup().as_operand(), ", ".join(table))

artiq/compiler/transforms/artiq_ir_generator.py

@@ -466,23 +466,29 @@ class ARTIQIRGenerator(algorithm.Visitor):
         self.append(ir.Branch(self.continue_target))
 
     def raise_exn(self, exn):
-        loc_file = ir.Constant(self.current_loc.source_buffer.name, builtins.TStr())
-        loc_line = ir.Constant(self.current_loc.line(), builtins.TInt(types.TValue(32)))
-        loc_column = ir.Constant(self.current_loc.column(), builtins.TInt(types.TValue(32)))
-        self.append(ir.SetAttr(exn, "__file__", loc_file))
-        self.append(ir.SetAttr(exn, "__line__", loc_line))
-        self.append(ir.SetAttr(exn, "__col__", loc_column))
-        if self.unwind_target:
-            self.append(ir.Raise(exn, self.unwind_target))
+        if exn is not None:
+            loc_file = ir.Constant(self.current_loc.source_buffer.name, builtins.TStr())
+            loc_line = ir.Constant(self.current_loc.line(), builtins.TInt(types.TValue(32)))
+            loc_column = ir.Constant(self.current_loc.column(), builtins.TInt(types.TValue(32)))
+            self.append(ir.SetAttr(exn, "__file__", loc_file))
+            self.append(ir.SetAttr(exn, "__line__", loc_line))
+            self.append(ir.SetAttr(exn, "__col__", loc_column))
+
+            if self.unwind_target is not None:
+                self.append(ir.Raise(exn, self.unwind_target))
+            else:
+                self.append(ir.Raise(exn))
         else:
-            self.append(ir.Raise(exn))
+            if self.unwind_target is not None:
+                self.append(ir.Reraise(self.unwind_target))
+            else:
+                self.append(ir.Reraise())
 
     def visit_Raise(self, node):
         self.raise_exn(self.visit(node.exc))
 
     def visit_Try(self, node):
         dispatcher = self.add_block("try.dispatch")
-        landingpad = dispatcher.append(ir.LandingPad())
 
         if any(node.finalbody):
             # k for continuation
@@ -532,8 +538,10 @@ class ARTIQIRGenerator(algorithm.Visitor):
                 self.continue_target = old_continue
             self.return_target = old_return
 
+        cleanup = self.add_block('handler.cleanup')
+        landingpad = dispatcher.append(ir.LandingPad(cleanup))
+
         handlers = []
-        has_catchall = False
         for handler_node in node.handlers:
             exn_type = handler_node.name_type.find()
             if handler_node.filter is not None and \
@@ -543,7 +551,6 @@ class ARTIQIRGenerator(algorithm.Visitor):
             else:
                 handler = self.add_block("handler.catchall")
                 landingpad.add_clause(handler, None)
-                has_catchall = True
 
             self.current_block = handler
             if handler_node.name is not None:
@@ -561,9 +568,13 @@ class ARTIQIRGenerator(algorithm.Visitor):
             self.visit(node.finalbody)
             post_finalizer = self.current_block
 
+            reraise = self.add_block('try.reraise')
+            reraise.append(ir.Reraise(self.unwind_target))
+
         self.current_block = tail = self.add_block("try.tail")
         if any(node.finalbody):
             final_targets.append(tail)
+            final_targets.append(reraise)
 
             if self.break_target:
                 break_proxy.append(ir.Branch(finalizer))
@@ -575,17 +586,13 @@ class ARTIQIRGenerator(algorithm.Visitor):
                 body.append(ir.SetLocal(final_state, ".k", tail))
                 body.append(ir.Branch(finalizer))
 
-            if not has_catchall:
-                # Add a catch-all handler so that finally would have a chance
-                # to execute.
-                handler = self.add_block("handler.catchall")
-                landingpad.add_clause(handler, None)
-                handlers.append((handler, handler))
+            cleanup.append(ir.SetLocal(final_state, ".k", reraise))
+            cleanup.append(ir.Branch(finalizer))
 
             for handler, post_handler in handlers:
                 if not post_handler.is_terminated():
                     post_handler.append(ir.SetLocal(final_state, ".k", tail))
-                    post_handler.append(ir.Branch(tail))
+                    post_handler.append(ir.Branch(finalizer))
 
             if not post_finalizer.is_terminated():
                 dest = post_finalizer.append(ir.GetLocal(final_state, ".k"))
@@ -594,6 +601,8 @@ class ARTIQIRGenerator(algorithm.Visitor):
             if not body.is_terminated():
                 body.append(ir.Branch(tail))
 
+            cleanup.append(ir.Reraise(self.unwind_target))
+
             for handler, post_handler in handlers:
                 if not post_handler.is_terminated():
                     post_handler.append(ir.Branch(tail))

artiq/compiler/transforms/dead_code_eliminator.py

@@ -15,7 +15,9 @@ class DeadCodeEliminator:
 
     def process_function(self, func):
         for block in func.basic_blocks:
-            if not any(block.predecessors()) and block != func.entry():
+            if not any(block.predecessors()) and \
+                    not any([isinstance(use, ir.SetLocal) for use in block.uses]) and \
+                    block != func.entry():
                 self.remove_block(block)
 
     def remove_block(self, block):
@@ -25,10 +27,6 @@ class DeadCodeEliminator:
                 use.remove_incoming_block(block)
                 if not any(use.operands):
                     self.remove_instruction(use)
-            elif isinstance(use, ir.SetLocal):
-                # Setting the target for `finally` resumption, e.g.
-                #   setlocal(.k) %v.4, label %try.doreturn
-                use.erase()
             else:
                 assert False
 

artiq/compiler/transforms/inferencer.py

@@ -956,13 +956,14 @@ class Inferencer(algorithm.Visitor):
     def visit_Raise(self, node):
         self.generic_visit(node)
 
-        exc_type = node.exc.type
-        if not types.is_var(exc_type) and not builtins.is_exception(exc_type):
-            diag = diagnostic.Diagnostic("error",
-                "cannot raise a value of type {type}, which is not an exception",
-                {"type": types.TypePrinter().name(exc_type)},
-                node.exc.loc)
-            self.engine.process(diag)
+        if node.exc is not None:
+            exc_type = node.exc.type
+            if not types.is_var(exc_type) and not builtins.is_exception(exc_type):
+                diag = diagnostic.Diagnostic("error",
+                    "cannot raise a value of type {type}, which is not an exception",
+                    {"type": types.TypePrinter().name(exc_type)},
+                    node.exc.loc)
+                self.engine.process(diag)
 
     def visit_Assert(self, node):
         self.generic_visit(node)

artiq/compiler/transforms/llvm_ir_generator.py

@@ -137,13 +137,19 @@ class LLVMIRGenerator:
             llty = ll.FunctionType(ll.DoubleType(), [ll.DoubleType(), ll.DoubleType()])
         elif name == "printf":
             llty = ll.FunctionType(ll.VoidType(), [ll.IntType(8).as_pointer()], var_arg=True)
-        elif name == "__artiq_raise":
-            llty = ll.FunctionType(ll.VoidType(), [self.llty_of_type(builtins.TException())])
         elif name == "__artiq_personality":
             llty = ll.FunctionType(ll.IntType(32), [], var_arg=True)
+        elif name == "__artiq_raise":
+            llty = ll.FunctionType(ll.VoidType(), [self.llty_of_type(builtins.TException())])
+        elif name == "__artiq_reraise":
+            llty = ll.FunctionType(ll.VoidType(), [])
         else:
             assert False
-        return ll.Function(self.llmodule, llty, name)
+
+        llfun = ll.Function(self.llmodule, llty, name)
+        if name in ("__artiq_raise", "__artiq_reraise", "llvm.trap"):
+            llfun.attributes.add("noreturn")
+        return llfun
 
     def map(self, value):
         if isinstance(value, (ir.Argument, ir.Instruction, ir.BasicBlock)):
@@ -599,12 +605,20 @@ class LLVMIRGenerator:
         llinsn.attributes.add('noreturn')
         return llinsn
 
+    def process_Reraise(self, insn):
+        llinsn = self.llbuilder.call(self.llbuiltin("__artiq_reraise"), [],
+                                     name=insn.name)
+        llinsn.attributes.add('noreturn')
+        self.llbuilder.unreachable()
+        return llinsn
+
     def process_LandingPad(self, insn):
         # Layout on return from landing pad: {%_Unwind_Exception*, %Exception*}
         lllandingpadty = ll.LiteralStructType([ll.IntType(8).as_pointer(),
                                                ll.IntType(8).as_pointer()])
         lllandingpad = self.llbuilder.landingpad(lllandingpadty,
-                                                 self.llbuiltin("__artiq_personality"))
+                                                 self.llbuiltin("__artiq_personality"),
+                                                 cleanup=True)
         llrawexn = self.llbuilder.extract_value(lllandingpad, 1)
         llexn = self.llbuilder.bitcast(llrawexn, self.llty_of_type(insn.type))
         llexnnameptr = self.llbuilder.gep(llexn, [self.llindex(0), self.llindex(0)])
@@ -627,7 +641,7 @@ class LLVMIRGenerator:
                     self.llbuilder.branch(self.map(target))
 
         if self.llbuilder.basic_block.terminator is None:
-            self.llbuilder.resume(lllandingpad)
+            self.llbuilder.branch(self.map(insn.cleanup()))
 
         return llexn
 

lit-test/test/exceptions/catch.py

@@ -1,4 +1,5 @@
-# RUN: %python -m artiq.compiler.testbench.jit %s
+# RUN: %python -m artiq.compiler.testbench.jit %s >%t
+# RUN: OutputCheck %s --file-to-check=%t
 # REQUIRES: exceptions
 
 try:

lit-test/test/exceptions/catch_all.py

@@ -1,4 +1,5 @@
-# RUN: %python -m artiq.compiler.testbench.jit %s
+# RUN: %python -m artiq.compiler.testbench.jit %s >%t
+# RUN: OutputCheck %s --file-to-check=%t
 # REQUIRES: exceptions
 
 def catch(f):

lit-test/test/exceptions/catch_multi.py

@@ -1,4 +1,5 @@
-# RUN: %python -m artiq.compiler.testbench.jit %s
+# RUN: %python -m artiq.compiler.testbench.jit %s >%t
+# RUN: OutputCheck %s --file-to-check=%t
 # REQUIRES: exceptions
 
 def catch(f):

lit-test/test/exceptions/catch_outer.py

@@ -1,4 +1,5 @@
-# RUN: %python -m artiq.compiler.testbench.jit %s
+# RUN: %python -m artiq.compiler.testbench.jit %s >%t
+# RUN: OutputCheck %s --file-to-check=%t
 # REQUIRES: exceptions
 
 def f():

lit-test/test/exceptions/finally.py

@@ -0,0 +1,21 @@
+# RUN: %python -m artiq.compiler.testbench.jit %s >%t
+# RUN: OutputCheck %s --file-to-check=%t
+# REQUIRES: exceptions
+
+def f():
+    try:
+        1/0
+    finally:
+        print("f-fin")
+    print("f-out")
+
+def g():
+    try:
+        f()
+    except:
+        print("g-except")
+
+# CHECK-L: f-fin
+# CHECK-NOT-L: f-out
+# CHECK-L: g-except
+g()

lit-test/test/exceptions/finally_catch.py

@@ -0,0 +1,17 @@
+# RUN: %python -m artiq.compiler.testbench.jit %s >%t
+# RUN: OutputCheck %s --file-to-check=%t
+# REQUIRES: exceptions
+
+def f():
+    try:
+        1/0
+    except:
+        print("f-except")
+    finally:
+        print("f-fin")
+    print("f-out")
+
+# CHECK-L: f-except
+# CHECK-L: f-fin
+# CHECK-L: f-out
+f()

lit-test/test/exceptions/finally_raise.py

@@ -0,0 +1,23 @@
+# RUN: %python -m artiq.compiler.testbench.jit %s >%t
+# RUN: OutputCheck %s --file-to-check=%t
+# REQUIRES: exceptions
+
+def f():
+    try:
+        1/0
+    finally:
+        print("f-fin")
+        raise ValueError()
+
+def g():
+    try:
+        f()
+    except ZeroDivisionError:
+        print("g-except-zde")
+    except ValueError:
+        print("g-except-ve")
+
+# CHECK-L: f-fin
+# CHECK-L: g-except-ve
+# CHECK-NOT-L: g-except-zde
+g()

lit-test/test/exceptions/finally_squash.py

@@ -0,0 +1,21 @@
+# RUN: %python -m artiq.compiler.testbench.jit %s >%t
+# RUN: OutputCheck %s --file-to-check=%t
+# REQUIRES: exceptions
+
+def f():
+    try:
+        1/0
+    finally:
+        print("f-fin")
+        return
+
+def g():
+    try:
+        f()
+    except:
+        print("g-except")
+
+# CHECK-L: f-fin
+# CHECK-NOT-L: f-out
+# CHECK-NOT-L: g-except
+g()

lit-test/test/exceptions/reraise.py

@@ -0,0 +1,16 @@
+# RUN: %not %python -m artiq.compiler.testbench.jit %s >%t
+# RUN: OutputCheck %s --file-to-check=%t
+# REQUIRES: exceptions
+
+def f():
+    # CHECK-L: Uncaught ZeroDivisionError
+    # CHECK-L: at input.py:${LINE:+1}:
+    1/0
+
+def g():
+    try:
+        f()
+    except:
+        raise
+
+g()

lit-test/test/exceptions/reraise_update.py

@@ -0,0 +1,16 @@
+# RUN: %not %python -m artiq.compiler.testbench.jit %s >%t
+# RUN: OutputCheck %s --file-to-check=%t
+# REQUIRES: exceptions
+
+def f():
+    1/0
+
+def g():
+    try:
+        f()
+    except Exception as e:
+        # CHECK-L: Uncaught ZeroDivisionError
+        # CHECK-L: at input.py:${LINE:+1}:
+        raise e
+
+g()

lit-test/test/exceptions/uncaught.py

@@ -1,6 +1,7 @@
-# RUN: %not %python -m artiq.compiler.testbench.jit %s
+# RUN: %not %python -m artiq.compiler.testbench.jit %s >%t
+# RUN: OutputCheck %s --file-to-check=%t
 # REQUIRES: exceptions
 
 # CHECK-L: Uncaught ZeroDivisionError: cannot divide by zero (0, 0, 0)
-# CHECK-L: at input.py:${LINE:+1}:0
+# CHECK-L: at input.py:${LINE:+1}:
 1/0

lit-test/test/integration/finally.py

@@ -62,3 +62,15 @@ def i():
 # CHECK-NOT-L: i-out
 # CHECK-L: i 30
 print("i", i())
+
+def j():
+    try:
+        print("j-try")
+    finally:
+        print("j-finally")
+    print("j-out")
+
+# CHECK-L: j-try
+# CHECK-L: j-finally
+# CHECK-L: j-out
+print("j", j())

soc/runtime/artiq_personality.c

@@ -8,8 +8,8 @@
 /* Logging */
 
 #ifndef NDEBUG
-#define EH_LOG0(fmt)     fprintf(stderr, "__artiq_personality: " fmt "\n")
-#define EH_LOG(fmt, ...) fprintf(stderr, "__artiq_personality: " fmt "\n", __VA_ARGS__)
+#define EH_LOG0(fmt)     fprintf(stderr, "%s: " fmt "\n", __func__)
+#define EH_LOG(fmt, ...) fprintf(stderr, "%s: " fmt "\n", __func__, __VA_ARGS__)
 #else
 #define EH_LOG0(fmt)
 #define EH_LOG(fmt, ...)
@@ -17,7 +17,7 @@
 
 #define EH_FAIL(err) \
   do { \
-    fprintf(stderr, "__artiq_personality fatal: %s\n", err); \
+    fprintf(stderr, "%s fatal: %s\n", __func__, err); \
     abort(); \
   } while(0)
 
@@ -195,37 +195,61 @@ static uintptr_t readEncodedPointer(const uint8_t **data, uint8_t encoding) {
 }
 
 
-/* Raising and catching */
+/* Raising */
 
 #define ARTIQ_EXCEPTION_CLASS 0x4152545141525451LL // 'ARTQARTQ'
 
+static void __artiq_cleanup(_Unwind_Reason_Code reason, struct _Unwind_Exception *exc);
+
 struct artiq_raised_exception {
   struct _Unwind_Exception unwind;
   struct artiq_exception artiq;
+  int handled;
 };
 
+static struct artiq_raised_exception inflight;
+
+void __artiq_raise(struct artiq_exception *artiq_exn) {
+  EH_LOG("===> raise (name=%s)", artiq_exn->name);
+
+  memmove(&inflight.artiq, artiq_exn, sizeof(struct artiq_exception));
+  inflight.unwind.exception_class = ARTIQ_EXCEPTION_CLASS;
+  inflight.unwind.exception_cleanup = &__artiq_cleanup;
+  inflight.handled = 0;
+
+  _Unwind_Reason_Code result = _Unwind_RaiseException(&inflight.unwind);
+  EH_ASSERT((result == _URC_END_OF_STACK) &&
+            "Unexpected error during unwinding");
+
+  // If we're here, there are no handlers, only cleanups.
+  __artiq_terminate(&inflight.artiq);
+}
+
+void __artiq_reraise() {
+  if(inflight.handled) {
+    EH_LOG0("===> reraise");
+    __artiq_raise(&inflight.artiq);
+  } else {
+    EH_LOG0("===> resume");
+    EH_ASSERT((inflight.artiq.typeinfo != 0) &&
+              "Need an exception to reraise");
+    _Unwind_Resume(&inflight.unwind);
+    abort();
+  }
+}
+
+/* Catching */
+
+// The code below does not refer to the `inflight` global.
+
 static void __artiq_cleanup(_Unwind_Reason_Code reason, struct _Unwind_Exception *exc) {
+  EH_LOG0("===> cleanup");
   struct artiq_raised_exception *inflight = (struct artiq_raised_exception*) exc;
   // The in-flight exception is statically allocated, so we don't need to free it.
   // But, we clear it to mark it as processed.
   memset(&inflight->artiq, 0, sizeof(struct artiq_exception));
 }
 
-void __artiq_raise(struct artiq_exception *artiq_exn) {
-  static struct artiq_raised_exception inflight;
-  memcpy(&inflight.artiq, artiq_exn, sizeof(struct artiq_exception));
-  inflight.unwind.exception_class = ARTIQ_EXCEPTION_CLASS;
-  inflight.unwind.exception_cleanup = &__artiq_cleanup;
-
-  _Unwind_Reason_Code result = _Unwind_RaiseException(&inflight.unwind);
-  if(result == _URC_END_OF_STACK) {
-    __artiq_terminate(&inflight.artiq);
-  } else {
-    fprintf(stderr, "__artiq_raise: unexpected error (%d)\n", result);
-    abort();
-  }
-}
-
 _Unwind_Reason_Code __artiq_personality(
         int version, _Unwind_Action actions, uint64_t exceptionClass,
         struct _Unwind_Exception *exceptionObject, struct _Unwind_Context *context) {
@@ -345,6 +369,9 @@ _Unwind_Reason_Code __artiq_personality(
       if(!(actions & _UA_SEARCH_PHASE)) {
         EH_LOG0("=> jumping to landing pad");
 
+        if(actions & _UA_HANDLER_FRAME)
+          inflight->handled = 1;
+
         _Unwind_SetGR(context, __builtin_eh_return_data_regno(0),
                       (uintptr_t)exceptionObject);
         _Unwind_SetGR(context, __builtin_eh_return_data_regno(1),

soc/runtime/artiq_personality.h

@@ -19,10 +19,15 @@ struct artiq_exception {
 extern "C" {
 #endif
 
-void __artiq_terminate(struct artiq_exception *artiq_exn)
+/* Provided by the runtime */
+void __artiq_raise(struct artiq_exception *artiq_exn)
+        __attribute__((noreturn));
+void __artiq_reraise()
         __attribute__((noreturn));
 
-void __artiq_raise(struct artiq_exception *artiq_exn);
+/* Called by the runtime */
+void __artiq_terminate(struct artiq_exception *artiq_exn)
+        __attribute__((noreturn));
 
 #ifdef __cplusplus
 }