support for the Genode OS framework (#5560)

compiler/ccgexprs.nim

@@ -944,7 +944,6 @@ proc genEcho(p: BProc, n: PNode) =
   # this unusal way of implementing it ensures that e.g. ``echo("hallo", 45)``
   # is threadsafe.
   internalAssert n.kind == nkBracket
-  p.module.includeHeader("<stdio.h>")
   var args: Rope = nil
   var a: TLoc
   for i in countup(0, n.len-1):
@@ -953,9 +952,15 @@ proc genEcho(p: BProc, n: PNode) =
     else:
       initLocExpr(p, n.sons[i], a)
       addf(args, ", $1? ($1)->data:\"nil\"", [rdLoc(a)])
-  linefmt(p, cpsStmts, "printf($1$2);$n",
-          makeCString(repeat("%s", n.len) & tnl), args)
-  linefmt(p, cpsStmts, "fflush(stdout);$n")
+  if platform.targetOS == osGenode:
+    # bypass libc and print directly to the Genode LOG session
+    p.module.includeHeader("<base/log.h>")
+    linefmt(p, cpsStmts, """Genode::log(""$1);$n""", args)
+  else:
+    p.module.includeHeader("<stdio.h>")
+    linefmt(p, cpsStmts, "printf($1$2);$n",
+            makeCString(repeat("%s", n.len) & tnl), args)
+    linefmt(p, cpsStmts, "fflush(stdout);$n")
 
 proc gcUsage(n: PNode) =
   if gSelectedGC == gcNone: message(n.info, warnGcMem, n.renderTree)

compiler/cgen.nim

@@ -966,6 +966,19 @@ proc genMainProc(m: BModule) =
         MainProcs &
       "}$N$N"
 
+    GenodeNimMain =
+      "Libc::Env *genodeEnv;$N" &
+      NimMainBody
+
+    ComponentConstruct =
+      "void Libc::Component::construct(Libc::Env &env) {$N" &
+      "\tgenodeEnv = &env;$N" &
+      "\tLibc::with_libc([&] () {$n\t" &
+      MainProcs &
+      "\t});$N" &
+      "\tenv.parent().exit(0);$N" &
+      "}$N$N"
+
   var nimMain, otherMain: FormatStr
   if platform.targetOS == osWindows and
       gGlobalOptions * {optGenGuiApp, optGenDynLib} != {}:
@@ -976,6 +989,9 @@ proc genMainProc(m: BModule) =
       nimMain = WinNimDllMain
       otherMain = WinCDllMain
     m.includeHeader("<windows.h>")
+  elif platform.targetOS == osGenode:
+    nimMain = GenodeNimMain
+    otherMain = ComponentConstruct
   elif optGenDynLib in gGlobalOptions:
     nimMain = PosixNimDllMain
     otherMain = PosixCDllMain

compiler/platform.nim

@@ -21,7 +21,7 @@ type
                     # conditionals to condsyms (end of module).
     osNone, osDos, osWindows, osOs2, osLinux, osMorphos, osSkyos, osSolaris,
     osIrix, osNetbsd, osFreebsd, osOpenbsd, osDragonfly, osAix, osPalmos, osQnx,
-    osAmiga, osAtari, osNetware, osMacos, osMacosx, osHaiku, osVxworks,
+    osAmiga, osAtari, osNetware, osMacos, osMacosx, osHaiku, osVxworks, osGenode
     osJS, osNimrodVM, osStandalone
 
 type
@@ -147,6 +147,11 @@ const
       objExt: ".o", newLine: "\x0A", pathSep: ";", dirSep: "\\",
       scriptExt: ".sh", curDir: ".", exeExt: ".vxe", extSep: ".",
       props: {ospNeedsPIC, ospPosix, ospLacksThreadVars}),
+     (name: "Genode", pardir: "..", dllFrmt: "$1.lib.so", altDirSep: "/",
+      objExt: ".o", newLine: "\x0A", pathSep: ":", dirSep: "/",
+      scriptExt: "", curDir: "/", exeExt: "", extSep: ".",
+      props: {ospNeedsPIC, ospLacksThreadVars}),
+
      (name: "JS", parDir: "..",
       dllFrmt: "lib$1.so", altDirSep: "/",
       objExt: ".o", newLine: "\x0A",