Unhandled exceptions handling brought back.

compiler/jsgen.nim

@@ -505,12 +505,12 @@ proc moveInto(p: PProc, src: var TCompRes, dest: TCompRes) =
 proc genTry(p: PProc, n: PNode, r: var TCompRes) =
   # code to generate:
   #
-  #  var sp = {prev: excHandler, exc: null};
-  #  excHandler = sp;
+  #  ++excHandler;
   #  try {
   #    stmts;
   #  } catch (EXC) {
   #    var prevJSError = lastJSError; lastJSError = EXC;
+  #    --excHandler;
   #    if (e.typ && e.typ == NTI433 || e.typ == NTI2321) {
   #      stmts;
   #    } else if (e.typ && e.typ == NTI32342) {
@@ -527,6 +527,11 @@ proc genTry(p: PProc, n: PNode, r: var TCompRes) =
     r.kind = resVal
     r.res = getTemp(p)
   inc(p.unique)
+  var i = 1
+  var length = sonsLen(n)
+  var catchBranchesExist = length > 1 and n.sons[i].kind == nkExceptBranch
+  if catchBranchesExist:
+    add(p.body, "++excHandler;" & tnl)
   var safePoint = "Tmp$1" % [rope(p.unique)]
   addf(p.body,
        "" |
@@ -534,15 +539,13 @@ proc genTry(p: PProc, n: PNode, r: var TCompRes) =
        [safePoint])
   if optStackTrace in p.options: add(p.body, "framePtr = F;" & tnl)
   addf(p.body, "try {$n" | "function()$n", [])
-  var length = sonsLen(n)
   var a: TCompRes
   gen(p, n.sons[0], a)
   moveInto(p, a, r)
-  var i = 1
   var generalCatchBranchExists = false
-  var catchBranchesExist = length > 1 and n.sons[i].kind == nkExceptBranch
   if p.target == targetJS and catchBranchesExist:
-    addf(p.body, "} catch (EXC) {$n var prevJSError = lastJSError; lastJSError = EXC;$n", [])
+    addf(p.body, "} catch (EXC) {$n var prevJSError = lastJSError;$n" &
+        " lastJSError = EXC;$n --excHandler;$n", [])
   elif p.target == targetLua:
     addf(p.body, "end)$n", [])
   while i < length and n.sons[i].kind == nkExceptBranch:
@@ -574,7 +577,7 @@ proc genTry(p: PProc, n: PNode, r: var TCompRes) =
     if catchBranchesExist:
       if not generalCatchBranchExists:
         useMagic(p, "reraiseException")
-        add(p.body, "else { reraiseException(); }")
+        add(p.body, "else {" & tnl & "reraiseException();" & tnl & "}" & tnl)
       add(p.body, "lastJSError = prevJSError;" & tnl)
     add(p.body, "} finally {" & tnl)
   if i < length and n.sons[i].kind == nkFinally:
@@ -1685,7 +1688,7 @@ proc genHeader(): Rope =
   result = ("/* Generated by the Nim Compiler v$1 */$n" &
             "/*   (c) 2015 Andreas Rumpf */$n$n" &
             "var framePtr = null;$n" &
-            "var excHandler = null;$n" &
+            "var excHandler = 0;$n" &
             "var lastJSError = null;$n") %
            [rope(VersionAsString)]
 

lib/system/jssys.nim

@@ -37,6 +37,7 @@ type
 
 var
   framePtr {.importc, nodecl, volatile.}: PCallFrame
+  excHandler {.importc, nodecl, volatile.}: int = 0
   lastJSError {.importc, nodecl, volatile.}: PJSError = nil
 
 {.push stacktrace: off, profiler:off.}
@@ -94,15 +95,38 @@ proc rawWriteStackTrace(): string =
   else:
     result = "No stack traceback available\n"
 
+proc unhandledException(e: ref Exception) {.
+    compilerproc, asmNoStackFrame.} =
+  when NimStackTrace:
+    var buf = rawWriteStackTrace()
+  else:
+    var buf = ""
+    if e.msg != nil and e.msg[0] != '\0':
+      add(buf, "Error: unhandled exception: ")
+      add(buf, e.msg)
+    else:
+      add(buf, "Error: unhandled exception")
+    add(buf, " [")
+    add(buf, e.name)
+    add(buf, "]\n")
+    alert(buf)
+
 proc raiseException(e: ref Exception, ename: cstring) {.
     compilerproc, asmNoStackFrame.} =
   e.name = ename
+  if excHandler == 0:
+    unhandledException(e)
   asm "throw `e`;"
 
 proc reraiseException() {.compilerproc, asmNoStackFrame.} =
   if lastJSError == nil:
     raise newException(ReraiseError, "no exception to reraise")
   else:
+    if excHandler == 0:
+      var isNimException : bool
+      asm "`isNimException` = lastJSError.m_type;"
+      if isNimException:
+        unhandledException(cast[ref Exception](lastJSError))
     asm "throw lastJSError;"
 
 proc raiseOverflow {.exportc: "raiseOverflow", noreturn.} =