From 79d020dd3a1e4d507a8f925df8f2bb2c0d52577d Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Thu, 31 Dec 2015 22:23:13 +0800
Subject: [PATCH] transforms.artiq_ir_generator: handle terminated try body.

---
 .../compiler/transforms/artiq_ir_generator.py | 14 +++++++++++--
 artiq/coredevice/core.py                      | 21 +++++++++++--------
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/artiq/compiler/transforms/artiq_ir_generator.py b/artiq/compiler/transforms/artiq_ir_generator.py
index 66958e544..3eb05a0a0 100644
--- a/artiq/compiler/transforms/artiq_ir_generator.py
+++ b/artiq/compiler/transforms/artiq_ir_generator.py
@@ -150,14 +150,21 @@ class ARTIQIRGenerator(algorithm.Visitor):
         else:
             insn.drop_references()
 
+    def warn_unreachable(self, node):
+        diag = diagnostic.Diagnostic("warning",
+            "unreachable code", {},
+            node.loc.begin())
+        self.engine.process(diag)
+
     # Visitors
 
     def visit(self, obj):
         if isinstance(obj, list):
             for elt in obj:
-                self.visit(elt)
                 if self.current_block.is_terminated():
+                    self.warn_unreachable(elt)
                     break
+                self.visit(elt)
         elif isinstance(obj, ast.AST):
             try:
                 old_loc, self.current_loc = self.current_loc, _extract_loc(obj)
@@ -615,7 +622,10 @@ class ARTIQIRGenerator(algorithm.Visitor):
         finally:
             self.unwind_target = old_unwind
 
-        self.visit(node.orelse)
+        if not body.is_terminated():
+            self.visit(node.orelse)
+        elif any(node.orelse):
+            self.warn_unreachable(node.orelse[0])
         body = self.current_block
 
         if any(node.finalbody):
diff --git a/artiq/coredevice/core.py b/artiq/coredevice/core.py
index 35e23225a..81fd9c00f 100644
--- a/artiq/coredevice/core.py
+++ b/artiq/coredevice/core.py
@@ -1,4 +1,4 @@
-import os
+import os, sys
 
 from pythonparser import diagnostic
 
@@ -13,21 +13,24 @@ from artiq.compiler.targets import OR1KTarget
 # Import for side effects (creating the exception classes).
 from artiq.coredevice import exceptions
 
+def _render_diagnostic(diagnostic):
+    def shorten_path(path):
+        return path.replace(os.path.normpath(os.path.join(__file__, "..", "..")), "<artiq>")
+    lines = [shorten_path(path) for path in diagnostic.render(colored=True)]
+    return "\n".join(lines)
+
+class _DiagnosticEngine(diagnostic.Engine):
+    def print_diagnostic(self, diagnostic):
+        sys.stderr.write(_render_diagnostic(diagnostic) + "\n")
 
 class CompileError(Exception):
     def __init__(self, diagnostic):
         self.diagnostic = diagnostic
 
-    def render_string(self, colored=False):
-        def shorten_path(path):
-            return path.replace(os.path.normpath(os.path.join(__file__, "..", "..")), "<artiq>")
-        lines = [shorten_path(path) for path in self.diagnostic.render(colored=colored)]
-        return "\n".join(lines)
-
     def __str__(self):
         # Prepend a newline so that the message shows up on after
         # exception class name printed by Python.
-        return "\n" + self.render_string(colored=True)
+        return "\n" + _render_diagnostic(self.diagnostic)
 
 
 @syscall
@@ -58,7 +61,7 @@ class Core:
 
     def compile(self, function, args, kwargs, set_result=None, with_attr_writeback=True):
         try:
-            engine = diagnostic.Engine(all_errors_are_fatal=True)
+            engine = _DiagnosticEngine(all_errors_are_fatal=True)
 
             stitcher = Stitcher(engine=engine)
             stitcher.stitch_call(function, args, kwargs, set_result)