make --gc:arc --exceptions:quirky work again [backport:1.4] (#16583)

* make --gc:arc --exceptions:quirky work again [backport:1.4]

* fixes #16404 [backport:1.4]

(cherry picked from commit 6317e4004d)

compiler/commands.nim

@@ -513,6 +513,8 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
         if pass in {passCmd2, passPP}:
           defineSymbol(conf.symbols, "nimSeqsV2")
           defineSymbol(conf.symbols, "nimV2")
+        if conf.exc == excNone and conf.backend != backendCpp:
+          conf.exc = excGoto
       of "orc":
         conf.selectedGC = gcOrc
         defineSymbol(conf.symbols, "gcdestructors")
@@ -522,6 +524,8 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
         if pass in {passCmd2, passPP}:
           defineSymbol(conf.symbols, "nimSeqsV2")
           defineSymbol(conf.symbols, "nimV2")
+        if conf.exc == excNone and conf.backend != backendCpp:
+          conf.exc = excGoto
       of "hooks":
         conf.selectedGC = gcHooks
         defineSymbol(conf.symbols, "gchooks")

compiler/main.nim

@@ -197,8 +197,6 @@ proc mainCommand*(graph: ModuleGraph) =
         # A better solution might be to fix system.nim
         undefSymbol(conf.symbols, "useNimRtl")
     of backendInvalid: doAssert false
-    if conf.selectedGC in {gcArc, gcOrc} and conf.backend != backendCpp:
-      conf.exc = excGoto
 
   var commandAlreadyProcessed = false
 

lib/system/embedded.nim

@@ -44,3 +44,13 @@ proc setControlCHook(hook: proc () {.noconv.}) = discard
 
 proc closureIterSetupExc(e: ref Exception) {.compilerproc, inline.} =
   sysFatal(ReraiseDefect, "exception handling is not available")
+
+when gotoBasedExceptions:
+  var nimInErrorMode {.threadvar.}: bool
+
+  proc nimErrorFlag(): ptr bool {.compilerRtl, inl.} =
+    result = addr(nimInErrorMode)
+
+  proc nimTestErrorFlag() {.compilerRtl.} =
+    if nimInErrorMode:
+      sysFatal(ReraiseDefect, "exception handling is not available")

tests/manyloc/standalone/panicoverride.nim

@@ -11,9 +11,4 @@ proc panic(s: string) {.noreturn.} =
   rawoutput(s)
   exit(1)
 
-# Alternatively we also could implement these 2 here:
-#
-# proc sysFatal(exceptn: typeDesc, message: string) {.noReturn.}
-# proc sysFatal(exceptn: typeDesc, message, arg: string) {.noReturn.}
-
 {.pop.}

tests/manyloc/standalone2/panicoverride.nim

@@ -0,0 +1,14 @@
+
+proc printf(frmt: cstring) {.varargs, importc, header: "<stdio.h>", cdecl.}
+proc exit(code: int) {.importc, header: "<stdlib.h>", cdecl.}
+
+{.push stack_trace: off, profiler:off.}
+
+proc rawoutput(s: string) =
+  printf("%s\n", s)
+
+proc panic(s: string) {.noreturn.} =
+  rawoutput(s)
+  exit(1)
+
+{.pop.}

tests/manyloc/standalone2/tavr.nim

@@ -0,0 +1,7 @@
+# bug #16404
+
+proc printf(frmt: cstring) {.varargs, header: "<stdio.h>", cdecl.}
+
+var x = 0
+inc x
+printf("hi %ld\n", x+4777)

tests/manyloc/standalone2/tavr.nim.cfg

@@ -0,0 +1,4 @@
+--gc:arc
+--cpu:avr
+--os:standalone
+--compileOnly