IC: yet another embarrassing omission (#17743)

* IC: yet another embarrassing omission

* VM: fewer hacks that kept IC from working

compiler/ast.nim

@@ -1054,7 +1054,7 @@ const
 
   defaultSize = -1
   defaultAlignment = -1
-  defaultOffset = -1
+  defaultOffset* = -1
 
 proc getPIdent*(a: PNode): PIdent {.inline.} =
   ## Returns underlying `PIdent` for `{nkSym, nkIdent}`, or `nil`.

compiler/ic/ic.nim

@@ -765,7 +765,8 @@ proc symHeaderFromPacked(c: var PackedDecoder; g: var PackedModuleGraph;
     kind: s.kind, magic: s.magic, flags: s.flags,
     info: translateLineInfo(c, g, si, s.info),
     options: s.options,
-    position: s.position,
+    position: if s.kind in {skForVar, skVar, skLet, skTemp}: 0 else: s.position,
+    offset: if s.kind in routineKinds: defaultOffset else: s.offset,
     name: getIdent(c.cache, g[si].fromDisk.sh.strings[s.name])
   )
 

compiler/vmdef.nim

@@ -10,6 +10,8 @@
 ## This module contains the type definitions for the new evaluation engine.
 ## An instruction is 1-3 int32s in memory, it is a register based VM.
 
+import std / tables
+
 import ast, idents, options, modulegraphs, lineinfos
 
 type TInstrType* = uint64
@@ -266,6 +268,7 @@ type
     profiler*: Profiler
     templInstCounter*: ref int # gives every template instantiation a unique ID, needed here for getAst
     vmstateDiff*: seq[(PSym, PNode)] # we remember the "diff" to global state here (feature for IC)
+    procToCodePos*: Table[int, int]
 
   PStackFrame* = ref TStackFrame
   TStackFrame* = object

compiler/vmgen.nim

@@ -27,6 +27,8 @@
 # solves the opcLdConst vs opcAsgnConst issue. Of course whether we need
 # this copy depends on the involved types.
 
+import std / tables
+
 import
   strutils, ast, types, msgs, renderer, vmdef,
   intsets, magicsys, options, lowerings, lineinfos, transf
@@ -2248,8 +2250,8 @@ proc optimizeJumps(c: PCtx; start: int) =
     else: discard
 
 proc genProc(c: PCtx; s: PSym): int =
-  var x = s.ast[miscPos]
-  if x.kind == nkEmpty or x[0].kind == nkEmpty:
+  let pos = c.procToCodePos.getOrDefault(s.id)
+  if pos == 0:
     #if s.name.s == "outterMacro" or s.name.s == "innerProc":
     #  echo "GENERATING CODE FOR ", s.name.s
     let last = c.code.len-1
@@ -2260,11 +2262,7 @@ proc genProc(c: PCtx; s: PSym): int =
       c.debug.setLen(last)
     #c.removeLastEof
     result = c.code.len+1 # skip the jump instruction
-    if x.kind == nkEmpty:
-      x = newTree(nkBracket, newIntNode(nkIntLit, result), x)
-    else:
-      x[0] = newIntNode(nkIntLit, result)
-    s.ast[miscPos] = x
+    c.procToCodePos[s.id] = result
     # thanks to the jmp we can add top level statements easily and also nest
     # procs easily:
     let body = transformBody(c.graph, c.idgen, s, cache = not isCompileTimeProc(s))
@@ -2297,4 +2295,4 @@ proc genProc(c: PCtx; s: PSym): int =
     c.prc = oldPrc
   else:
     c.prc.maxSlots = s.offset
-    result = x[0].intVal.int
+    result = pos