IC: green tests (#17311)

* IC: renamed to_packed_ast module to ic module

* IC: don't store the --forceBuild flag, makes it easier to test

* IC: enable hello world test

* Codegen: refactorings for IC; changed the name mangling algorithm

* fixed the HCR regressions

* life is too short for HCR

* tconvexhull is now allowed to use deepCopy

* IC exposed a stdlib bug, required a refactoring

* codegen: code cleanups

* IC: even if a module is outdated, its dependencies might come from disk

* IC: progress

* IC: better name mangling, module IDs are not stable

* IC: another refactoring helping with --ic:on --gc:arc

* disable arraymancer on Windows for the time being

* disable arraymancer altogether

* IC: make basic test work with 'nim cpp'

* IC: progress on --ic:on --gc:arc

* wip; name mangling for type info

compiler/msgs.nim

@@ -115,6 +115,7 @@ proc fileInfoIdx*(conf: ConfigRef; filename: AbsoluteFile; isKnownFile: var bool
   else:
     isKnownFile = false
     result = conf.m.fileInfos.len.FileIndex
+    #echo "ID ", result.int, " ", canon2
     conf.m.fileInfos.add(newFileInfo(canon, if pseudoPath: RelativeFile filename
                                             else: relativeTo(canon, conf.projectPath)))
     conf.m.filenameToIndexTbl[canon2] = result
@@ -630,3 +631,28 @@ template listMsg(title, r) =
 
 proc listWarnings*(conf: ConfigRef) = listMsg("Warnings:", warnMin..warnMax)
 proc listHints*(conf: ConfigRef) = listMsg("Hints:", hintMin..hintMax)
+
+proc uniqueModuleName*(conf: ConfigRef; fid: FileIndex): string =
+  ## The unique module name is guaranteed to only contain {'A'..'Z', 'a'..'z', '0'..'9', '_'}
+  ## so that it is useful as a C identifier snippet.
+  let path = AbsoluteFile toFullPath(conf, fid)
+  let rel =
+    if path.string.startsWith(conf.libpath.string):
+      relativeTo(path, conf.libpath).string
+    else:
+      relativeTo(path, conf.projectPath).string
+  let trunc = if rel.endsWith(".nim"): rel.len - len(".nim") else: rel.len
+  result = newStringOfCap(trunc)
+  for i in 0..<trunc:
+    let c = rel[i]
+    case c
+    of 'a'..'z':
+      result.add c
+    of {os.DirSep, os.AltSep}:
+      result.add 'Z' # because it looks a bit like '/'
+    of '.':
+      result.add 'O' # a circle
+    else:
+      # We mangle upper letters and digits too so that there cannot
+      # be clashes with our special meanings of 'Z' and 'O'
+      result.addInt ord(c)