nimRawSetjmp: support Windows (#19197)

* nimRawSetjmp: support Windows

Using `_setjmp()` directly is required to avoid some rare (but very
annoying) exception-related stack corruption leading to segfaults on
Windows, with Mingw-w64 and SEH.
More details: https://github.com/status-im/nimbus-eth2/issues/3121

Also add "nimBuiltinSetjmp" - mostly for benchmarking.

* fix for Apple's Clang++

tests/exception/texceptions.nim

@@ -1,4 +1,6 @@
 discard """
+  disabled: "windows" # no sigsetjmp() there
+  matrix: "-d:nimStdSetjmp; -d:nimSigSetjmp; -d:nimRawSetjmp; -d:nimBuiltinSetjmp"
   output: '''
 
 BEFORE
@@ -17,7 +19,7 @@ FINALLY
 
 echo ""
 
-proc no_expcetion =
+proc no_exception =
   try:
     echo "BEFORE"
 
@@ -28,7 +30,7 @@ proc no_expcetion =
   finally:
     echo "FINALLY"
 
-try: no_expcetion()
+try: no_exception()
 except: echo "RECOVER"
 
 echo ""

tests/exception/texceptions2.nim

@@ -0,0 +1,130 @@
+discard """
+  disabled: "posix" # already covered by texceptions.nim
+  matrix: "-d:nimStdSetjmp; -d:nimRawSetjmp; -d:nimBuiltinSetjmp"
+  output: '''
+
+BEFORE
+FINALLY
+
+BEFORE
+EXCEPT
+FINALLY
+RECOVER
+
+BEFORE
+EXCEPT: IOError: hi
+FINALLY
+'''
+"""
+
+echo ""
+
+proc no_exception =
+  try:
+    echo "BEFORE"
+
+  except:
+    echo "EXCEPT"
+    raise
+
+  finally:
+    echo "FINALLY"
+
+try: no_exception()
+except: echo "RECOVER"
+
+echo ""
+
+proc reraise_in_except =
+  try:
+    echo "BEFORE"
+    raise newException(IOError, "")
+
+  except IOError:
+    echo "EXCEPT"
+    raise
+
+  finally:
+    echo "FINALLY"
+
+try: reraise_in_except()
+except: echo "RECOVER"
+
+echo ""
+
+proc return_in_except =
+  try:
+    echo "BEFORE"
+    raise newException(IOError, "hi")
+
+  except:
+    echo "EXCEPT: ", getCurrentException().name, ": ", getCurrentExceptionMsg()
+    return
+
+  finally:
+    echo "FINALLY"
+
+try: return_in_except()
+except: echo "RECOVER"
+
+block: #10417
+  proc moo() {.noreturn.} = discard
+
+  let bar =
+    try:
+      1
+    except:
+      moo()
+
+  doAssert(bar == 1)
+
+# Make sure the VM handles the exceptions correctly
+block:
+  proc fun1(): seq[int] =
+    try:
+      try:
+        raise newException(ValueError, "xx")
+      except:
+        doAssert("xx" == getCurrentExceptionMsg())
+        raise newException(KeyError, "yy")
+    except:
+      doAssert("yy" == getCurrentExceptionMsg())
+      result.add(1212)
+    try:
+      try:
+        raise newException(AssertionDefect, "a")
+      finally:
+        result.add(42)
+    except AssertionDefect:
+      result.add(99)
+    finally:
+      result.add(10)
+    result.add(4)
+    result.add(0)
+    try:
+      result.add(1)
+    except KeyError:
+      result.add(-1)
+    except ValueError:
+      result.add(-1)
+    except IndexDefect:
+      result.add(2)
+    except:
+      result.add(3)
+
+    try:
+      try:
+        result.add(1)
+        return
+      except:
+        result.add(-1)
+      finally:
+        result.add(2)
+    except KeyError:
+      doAssert(false)
+    finally:
+      result.add(3)
+
+  let x1 = fun1()
+  const x2 = fun1()
+  doAssert(x1 == x2)