so close...

compiler/nir/ast2ir.nim

@@ -2353,6 +2353,11 @@ proc genParams(c: var ProcCon; params: PNode; prc: PSym) =
     let res = resNode.sym # get result symbol
     c.code.addSummon toLineInfo(c, res.info), toSymId(c, res),
       typeToIr(c.m, res.typ), SummonResult
+  elif prc.typ.len > 0 and not isEmptyType(prc.typ[0]) and not isCompileTimeOnly(prc.typ[0]):
+    # happens for procs without bodies:
+    let t = typeToIr(c.m, prc.typ[0])
+    let tmp = allocTemp(c, t)
+    c.code.addSummon toLineInfo(c, params.info), tmp, t, SummonResult
 
   for i in 1..<params.len:
     let s = params[i].sym

compiler/nir/nirinsts.nim

@@ -240,6 +240,8 @@ proc next*(tree: Tree; pos: var NodePos) {.inline.} = nextChild tree, int(pos)
 
 template firstSon*(n: NodePos): NodePos = NodePos(n.int+1)
 
+template skipTyped*(n: NodePos): NodePos = NodePos(n.int+2)
+
 iterator sons*(tree: Tree; n: NodePos): NodePos =
   var pos = n.int
   assert tree.nodes[pos].kind > LastAtomicValue
@@ -259,6 +261,17 @@ iterator sonsFrom1*(tree: Tree; n: NodePos): NodePos =
     yield NodePos pos
     nextChild tree, pos
 
+iterator sonsFrom2*(tree: Tree; n: NodePos): NodePos =
+  var pos = n.int
+  assert tree.nodes[pos].kind > LastAtomicValue
+  let last = pos + tree.nodes[pos].rawSpan
+  inc pos
+  nextChild tree, pos
+  nextChild tree, pos
+  while pos < last:
+    yield NodePos pos
+    nextChild tree, pos
+
 template `[]`*(t: Tree; n: NodePos): Instr = t.nodes[n.int]
 
 proc span(tree: Tree; pos: int): int {.inline.} =

compiler/nir/nirvm.nim

@@ -325,7 +325,7 @@ proc toString*(t: Bytecode; pos: CodePos;
     r.add $t.m.lit.numbers[LitId t[pos].operand]
   of StrValM:
     escapeToNimLit(t.m.lit.strings[LitId t[pos].operand], r)
-  of LoadLocalM, LoadGlobalM, LoadProcM, AllocLocals:
+  of LoadLocalM, LoadGlobalM, LoadProcM, AllocLocals, SummonParamM:
     r.add $t[pos].kind
     r.add ' '
     r.add $t[pos].operand
@@ -593,14 +593,14 @@ proc preprocess(c: var Preprocessing; bc: var Bytecode; t: Tree; n: NodePos; fla
     if t[src].kind in {Call, IndirectCall}:
       # No support for return values, these are mapped to `var T` parameters!
       build bc, info, CallM:
-        preprocess(c, bc, t, src.firstSon, {WantAddr})
+        preprocess(c, bc, t, src.skipTyped, {WantAddr})
         preprocess(c, bc, t, dest, {WantAddr})
-        for ch in sonsFrom1(t, src): preprocess(c, bc, t, ch, {WantAddr})
+        for ch in sonsFrom2(t, src): preprocess(c, bc, t, ch, {WantAddr})
     elif t[src].kind in {CheckedCall, CheckedIndirectCall}:
       build bc, info, CheckedCallM:
-        preprocess(c, bc, t, src.firstSon, {WantAddr})
+        preprocess(c, bc, t, src.skipTyped, {WantAddr})
         preprocess(c, bc, t, dest, {WantAddr})
-        for ch in sonsFrom1(t, src): preprocess(c, bc, t, ch, {WantAddr})
+        for ch in sonsFrom2(t, src): preprocess(c, bc, t, ch, {WantAddr})
     elif t[dest].kind == Load:
       let (typ, a) = sons2(t, dest)
       let s = computeSize(bc, tid)[0]
@@ -696,7 +696,7 @@ proc preprocess(c: var Preprocessing; bc: var Bytecode; t: Tree; n: NodePos; fla
       for ch in sons(t, n): preprocess(c2, bc, t, ch, {})
       bc.code[toPatch] = toIns(AllocLocals, c2.localsAddr)
     when false:
-      if here.int == 40192:
+      if here.int == 39850:
         debug bc, t, n
         debug bc, here
 
@@ -934,9 +934,12 @@ proc eval(c: Bytecode; pc: CodePos; s: StackFrame; result: pointer; size: int) =
   of LoadLocalM:
     let dest = s.locals +! c.code[pc].operand
     copyMem dest, result, size
-  of FieldAtM, ArrayAtM, LoadM:
+  of FieldAtM, ArrayAtM, LoadM, LoadGlobalM:
     let dest = evalAddr(c, pc, s)
     copyMem dest, result, size
+  of LoadProcM:
+    let procAddr = c.code[pc].operand
+    cast[ptr pointer](result)[] = cast[pointer](procAddr)
   of CheckedAddM: checkedBinop `+`
   of CheckedSubM: checkedBinop `-`
   of CheckedMulM: checkedBinop `*`
@@ -1082,8 +1085,8 @@ proc exec(c: Bytecode; pc: CodePos; u: ref Universe) =
           next c, prc
           assert c[prc].kind == ImmediateValM
           let paramSize = c[prc].operand.int
-          eval(c, a, s2, s2.locals +! paramAddr, paramSize)
           next c, prc
+          eval(c, a, s2, s2.locals +! paramAddr, paramSize)
         s = s2
         pc = prc
     of RetM: