'lock levels' are deprecated, now a noop (#20539)

* 'lock levels' are deprecated, now a noop

* fixes tests

Author: ringabout

changelog.md

@@ -84,6 +84,8 @@
 - `macros.getImpl` for `const` symbols now returns the full definition node
   (as `nnkConstDef`) rather than the AST of the constant value.
 
+- Lock levels are deprecated, now a noop.
+
 - ORC is now the default memory management strategy. Use
   `--mm:refc` for a transition period.
 

compiler/ast.nim

@@ -929,7 +929,6 @@ type
       allUsages*: seq[TLineInfo]
 
   TTypeSeq* = seq[PType]
-  TLockLevel* = distinct int16
 
   TTypeAttachedOp* = enum ## as usual, order is important here
     attachedDestructor,
@@ -963,7 +962,6 @@ type
                               # -1 means that the size is unkwown
     align*: int16             # the type's alignment requirements
     paddingAtEnd*: int16      #
-    lockLevel*: TLockLevel    # lock level as required for deadlock checking
     loc*: TLoc
     typeInst*: PType          # for generic instantiations the tyGenericInst that led to this
                               # type.
@@ -1499,17 +1497,9 @@ proc newProcNode*(kind: TNodeKind, info: TLineInfo, body: PNode,
                   pragmas, exceptions, body]
 
 const
-  UnspecifiedLockLevel* = TLockLevel(-1'i16)
-  MaxLockLevel* = 1000'i16
-  UnknownLockLevel* = TLockLevel(1001'i16)
   AttachedOpToStr*: array[TTypeAttachedOp, string] = [
     "=destroy", "=copy", "=sink", "=trace", "=deepcopy"]
 
-proc `$`*(x: TLockLevel): string =
-  if x.ord == UnspecifiedLockLevel.ord: result = "<unspecified>"
-  elif x.ord == UnknownLockLevel.ord: result = "<unknown>"
-  else: result = $int16(x)
-
 proc `$`*(s: PSym): string =
   if s != nil:
     result = s.name.s & "@" & $s.id
@@ -1519,7 +1509,6 @@ proc `$`*(s: PSym): string =
 proc newType*(kind: TTypeKind, id: ItemId; owner: PSym): PType =
   result = PType(kind: kind, owner: owner, size: defaultSize,
                  align: defaultAlignment, itemId: id,
-                 lockLevel: UnspecifiedLockLevel,
                  uniqueId: id)
   when false:
     if result.itemId.module == 55 and result.itemId.item == 2:
@@ -1544,7 +1533,6 @@ proc assignType*(dest, src: PType) =
   dest.n = src.n
   dest.size = src.size
   dest.align = src.align
-  dest.lockLevel = src.lockLevel
   # this fixes 'type TLock = TSysLock':
   if src.sym != nil:
     if dest.sym != nil:

compiler/cgmeth.nim

@@ -147,23 +147,6 @@ proc fixupDispatcher(meth, disp: PSym; conf: ConfigRef) =
      disp.ast[resultPos].kind == nkEmpty:
     disp.ast[resultPos] = copyTree(meth.ast[resultPos])
 
-  # The following code works only with lock levels, so we disable
-  # it when they're not available.
-  when declared(TLockLevel):
-    proc `<`(a, b: TLockLevel): bool {.borrow.}
-    proc `==`(a, b: TLockLevel): bool {.borrow.}
-    if disp.typ.lockLevel == UnspecifiedLockLevel:
-      disp.typ.lockLevel = meth.typ.lockLevel
-    elif meth.typ.lockLevel != UnspecifiedLockLevel and
-         meth.typ.lockLevel != disp.typ.lockLevel:
-      message(conf, meth.info, warnLockLevel,
-        "method has lock level $1, but another method has $2" %
-        [$meth.typ.lockLevel, $disp.typ.lockLevel])
-      # XXX The following code silences a duplicate warning in
-      # checkMethodeffects() in sempass2.nim for now.
-      if disp.typ.lockLevel < meth.typ.lockLevel:
-        disp.typ.lockLevel = meth.typ.lockLevel
-
 proc methodDef*(g: ModuleGraph; idgen: IdGenerator; s: PSym) =
   var witness: PSym
   for i in 0..<g.methods.len:

compiler/ic/ic.nim

@@ -354,7 +354,7 @@ proc storeType(t: PType; c: var PackedEncoder; m: var PackedModule): PackedItemI
 
     var p = PackedType(kind: t.kind, flags: t.flags, callConv: t.callConv,
       size: t.size, align: t.align, nonUniqueId: t.itemId.item,
-      paddingAtEnd: t.paddingAtEnd, lockLevel: t.lockLevel)
+      paddingAtEnd: t.paddingAtEnd)
     storeNode(p, t, n)
     p.typeInst = t.typeInst.storeType(c, m)
     for kid in items t.sons:
@@ -900,7 +900,7 @@ proc typeHeaderFromPacked(c: var PackedDecoder; g: var PackedModuleGraph;
                           t: PackedType; si, item: int32): PType =
   result = PType(itemId: ItemId(module: si, item: t.nonUniqueId), kind: t.kind,
                 flags: t.flags, size: t.size, align: t.align,
-                paddingAtEnd: t.paddingAtEnd, lockLevel: t.lockLevel,
+                paddingAtEnd: t.paddingAtEnd,
                 uniqueId: ItemId(module: si, item: item),
                 callConv: t.callConv)
 

compiler/ic/packed_ast.nim

@@ -84,7 +84,6 @@ type
     size*: BiggestInt
     align*: int16
     paddingAtEnd*: int16
-    lockLevel*: TLockLevel # lock level as required for deadlock checking
     # not serialized: loc*: TLoc because it is backend-specific
     typeInst*: PackedItemId
     nonUniqueId*: int32

compiler/lineinfos.nim

@@ -68,7 +68,8 @@ type
     warnUnreachableElse = "UnreachableElse", warnUnreachableCode = "UnreachableCode",
     warnStaticIndexCheck = "IndexCheck", warnGcUnsafe = "GcUnsafe", warnGcUnsafe2 = "GcUnsafe2",
     warnUninit = "Uninit", warnGcMem = "GcMem", warnDestructor = "Destructor",
-    warnLockLevel = "LockLevel", warnResultShadowed = "ResultShadowed",
+    warnLockLevel = "LockLevel", # deadcode
+    warnResultShadowed = "ResultShadowed",
     warnInconsistentSpacing = "Spacing",  warnCaseTransition = "CaseTransition",
     warnCycleCreated = "CycleCreated", warnObservableStores = "ObservableStores",
     warnStrictNotNil = "StrictNotNil",
@@ -161,7 +162,7 @@ const
     warnUninit: "use explicit initialization of '$1' for clarity",
     warnGcMem: "'$1' uses GC'ed memory",
     warnDestructor: "usage of a type with a destructor in a non destructible context. This will become a compile time error in the future.",
-    warnLockLevel: "$1",
+    warnLockLevel: "$1", # deadcode
     warnResultShadowed: "Special variable 'result' is shadowed.",
     warnInconsistentSpacing: "Number of spaces around '$#' is not consistent",
     warnCaseTransition: "Potential object case transition, instantiate new object instead",

compiler/main.nim

@@ -294,7 +294,6 @@ proc mainCommand*(graph: ModuleGraph) =
   of cmdDoc0: docLikeCmd commandDoc(cache, conf)
   of cmdDoc:
     docLikeCmd():
-      conf.setNoteDefaults(warnLockLevel, false) # issue #13218
       conf.setNoteDefaults(warnRstRedefinitionOfLabel, false) # issue #13218
         # because currently generates lots of false positives due to conflation
         # of labels links in doc comments, e.g. for random.rand:

compiler/pragmas.nim

@@ -684,23 +684,6 @@ proc pragmaLockStmt(c: PContext; it: PNode) =
       for i in 0..<n.len:
         n[i] = c.semExpr(c, n[i])
 
-proc pragmaLocks(c: PContext, it: PNode): TLockLevel =
-  if it.kind notin nkPragmaCallKinds or it.len != 2:
-    invalidPragma(c, it)
-  else:
-    case it[1].kind
-    of nkStrLit, nkRStrLit, nkTripleStrLit:
-      if it[1].strVal == "unknown":
-        result = UnknownLockLevel
-      else:
-        localError(c.config, it[1].info, "invalid string literal for locks pragma (only allowed string is \"unknown\")")
-    else:
-      let x = expectIntLit(c, it)
-      if x < 0 or x > MaxLockLevel:
-        localError(c.config, it[1].info, "integer must be within 0.." & $MaxLockLevel)
-      else:
-        result = TLockLevel(x)
-
 proc typeBorrow(c: PContext; sym: PSym, n: PNode) =
   if n.kind in nkPragmaCallKinds and n.len == 2:
     let it = n[1]
@@ -1196,7 +1179,7 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int,
       of wLocks:
         if sym == nil: pragmaLockStmt(c, it)
         elif sym.typ == nil: invalidPragma(c, it)
-        else: sym.typ.lockLevel = pragmaLocks(c, it)
+        else: warningDeprecated(c.config, n.info, "'Lock levels' are deprecated, now a noop")
       of wBitsize:
         if sym == nil or sym.kind != skField:
           invalidPragma(c, it)

compiler/semcall.nim

@@ -149,9 +149,6 @@ proc effectProblem(f, a: PType; result: var string; c: PContext) =
       of efTagsUnknown:
         result.add "\n  The `.tags` requirements differ. Annotate the " &
             "proc with {.tags: [].} to get extended error information."
-      of efLockLevelsDiffer:
-        result.add "\n  The `.locks` requirements differ. Annotate the " &
-            "proc with {.locks: 0.} to get extended error information."
       of efEffectsDelayed:
         result.add "\n  The `.effectsOf` annotations differ."
       of efTagsIllegal:

compiler/sempass2.nim

@@ -77,19 +77,13 @@ type
     gcUnsafe, isRecursive, isTopLevel, hasSideEffect, inEnforcedGcSafe: bool
     hasDangerousAssign, isInnerProc: bool
     inEnforcedNoSideEffects: bool
-    maxLockLevel, currLockLevel: TLockLevel
     currOptions: TOptions
     config: ConfigRef
     graph: ModuleGraph
     c: PContext
     escapingParams: IntSet
   PEffects = var TEffects
 
-proc `<`(a, b: TLockLevel): bool {.borrow.}
-proc `<=`(a, b: TLockLevel): bool {.borrow.}
-proc `==`(a, b: TLockLevel): bool {.borrow.}
-proc max(a, b: TLockLevel): TLockLevel {.borrow.}
-
 proc createTypeBoundOps(tracked: PEffects, typ: PType; info: TLineInfo) =
   if typ == nil: return
   when false:
@@ -107,33 +101,12 @@ proc isLocalVar(a: PEffects, s: PSym): bool =
   s.typ != nil and (s.kind in {skVar, skResult} or (s.kind == skParam and isOutParam(s.typ))) and
     sfGlobal notin s.flags and s.owner == a.owner
 
-proc getLockLevel(t: PType): TLockLevel =
-  var t = t
-  # tyGenericInst(TLock {tyGenericBody}, tyStatic, tyObject):
-  if t.kind == tyGenericInst and t.len == 3: t = t[1]
-  if t.kind == tyStatic and t.n != nil and t.n.kind in {nkCharLit..nkInt64Lit}:
-    result = t.n.intVal.TLockLevel
-
 proc lockLocations(a: PEffects; pragma: PNode) =
   if pragma.kind != nkExprColonExpr:
     localError(a.config, pragma.info, "locks pragma without argument")
     return
-  var firstLL = TLockLevel(-1'i16)
   for x in pragma[1]:
-    let thisLL = getLockLevel(x.typ)
-    if thisLL != 0.TLockLevel:
-      if thisLL < 0.TLockLevel or thisLL > MaxLockLevel.TLockLevel:
-        localError(a.config, x.info, "invalid lock level: " & $thisLL)
-      elif firstLL < 0.TLockLevel: firstLL = thisLL
-      elif firstLL != thisLL:
-        localError(a.config, x.info,
-          "multi-lock requires the same static lock level for every operand")
-      a.maxLockLevel = max(a.maxLockLevel, firstLL)
     a.locked.add x
-  if firstLL >= 0.TLockLevel and firstLL != a.currLockLevel:
-    if a.currLockLevel > 0.TLockLevel and a.currLockLevel <= firstLL:
-      localError(a.config, pragma.info, "invalid nested locking")
-    a.currLockLevel = firstLL
 
 proc guardGlobal(a: PEffects; n: PNode; guard: PSym) =
   # check whether the corresponding lock is held:
@@ -438,8 +411,6 @@ proc listEffects(a: PEffects) =
   for e in items(a.exc):  message(a.config, e.info, hintUser, typeToString(e.typ))
   for e in items(a.tags): message(a.config, e.info, hintUser, typeToString(e.typ))
   for e in items(a.forbids): message(a.config, e.info, hintUser, typeToString(e.typ))
-  #if a.maxLockLevel != 0:
-  #  message(e.info, hintUser, "lockLevel: " & a.maxLockLevel)
 
 proc catches(tracked: PEffects, e: PType) =
   let e = skipTypes(e, skipPtrs)
@@ -551,25 +522,6 @@ proc importedFromC(n: PNode): bool =
   # when imported from C, we assume GC-safety.
   result = n.kind == nkSym and sfImportc in n.sym.flags
 
-proc getLockLevel(s: PSym): TLockLevel =
-  result = s.typ.lockLevel
-  if result == UnspecifiedLockLevel:
-    if {sfImportc, sfNoSideEffect} * s.flags != {} or
-       tfNoSideEffect in s.typ.flags:
-      result = 0.TLockLevel
-    else:
-      result = UnknownLockLevel
-      #message(??.config, s.info, warnUser, "FOR THIS " & s.name.s)
-
-proc mergeLockLevels(tracked: PEffects, n: PNode, lockLevel: TLockLevel) =
-  if lockLevel >= tracked.currLockLevel:
-    # if in lock section:
-    if tracked.currLockLevel > 0.TLockLevel:
-      localError tracked.config, n.info, errGenerated,
-        "expected lock level < " & $tracked.currLockLevel &
-        " but got lock level " & $lockLevel
-    tracked.maxLockLevel = max(tracked.maxLockLevel, lockLevel)
-
 proc propagateEffects(tracked: PEffects, n: PNode, s: PSym) =
   let pragma = s.ast[pragmasPos]
   let spec = effectSpec(pragma, wRaises)
@@ -583,7 +535,6 @@ proc propagateEffects(tracked: PEffects, n: PNode, s: PSym) =
     markGcUnsafe(tracked, s)
   if tfNoSideEffect notin s.typ.flags:
     markSideEffect(tracked, s, n.info)
-  mergeLockLevels(tracked, n, s.getLockLevel)
 
 proc procVarCheck(n: PNode; conf: ConfigRef) =
   if n.kind in nkSymChoices:
@@ -623,11 +574,6 @@ proc notNilCheck(tracked: PEffects, n: PNode, paramType: PType) =
 proc assumeTheWorst(tracked: PEffects; n: PNode; op: PType) =
   addRaiseEffect(tracked, createRaise(tracked.graph, n), nil)
   addTag(tracked, createTag(tracked.graph, n), nil)
-  let lockLevel = if op.lockLevel == UnspecifiedLockLevel: UnknownLockLevel
-                  else: op.lockLevel
-  #if lockLevel == UnknownLockLevel:
-  #  message(??.config, n.info, warnUser, "had to assume the worst here")
-  mergeLockLevels(tracked, n, lockLevel)
 
 proc isOwnedProcVar(tracked: PEffects; n: PNode): bool =
   # XXX prove the soundness of this effect system rule
@@ -885,10 +831,9 @@ proc trackCall(tracked: PEffects; n: PNode) =
       if a.kind == nkSym:
         if a.sym == tracked.owner: tracked.isRecursive = true
         # even for recursive calls we need to check the lock levels (!):
-        mergeLockLevels(tracked, n, a.sym.getLockLevel)
         if sfSideEffect in a.sym.flags: markSideEffect(tracked, a, n.info)
       else:
-        mergeLockLevels(tracked, n, op.lockLevel)
+        discard
       var effectList = op.n[0]
       if a.kind == nkSym and a.sym.kind == skMethod:
         propagateEffects(tracked, n, a.sym)
@@ -967,7 +912,6 @@ proc trackCall(tracked: PEffects; n: PNode) =
 type
   PragmaBlockContext = object
     oldLocked: int
-    oldLockLevel: TLockLevel
     enforcedGcSafety, enforceNoSideEffects: bool
     oldExc, oldTags, oldForbids: int
     exc, tags, forbids: PNode
@@ -976,7 +920,6 @@ proc createBlockContext(tracked: PEffects): PragmaBlockContext =
   var oldForbidsLen = 0
   if tracked.forbids != nil: oldForbidsLen = tracked.forbids.len
   result = PragmaBlockContext(oldLocked: tracked.locked.len,
-    oldLockLevel: tracked.currLockLevel,
     enforcedGcSafety: false, enforceNoSideEffects: false,
     oldExc: tracked.exc.len, oldTags: tracked.tags.len,
     oldForbids: oldForbidsLen)
@@ -989,7 +932,6 @@ proc unapplyBlockContext(tracked: PEffects; bc: PragmaBlockContext) =
   if bc.enforcedGcSafety: tracked.inEnforcedGcSafe = false
   if bc.enforceNoSideEffects: tracked.inEnforcedNoSideEffects = false
   setLen(tracked.locked, bc.oldLocked)
-  tracked.currLockLevel = bc.oldLockLevel
   if bc.exc != nil:
     # beware that 'raises: []' is very different from not saying
     # anything about 'raises' in the 'cast' at all. Same applies for 'tags'.
@@ -1396,17 +1338,6 @@ proc checkMethodEffects*(g: ModuleGraph; disp, branch: PSym) =
       localError(g.config, branch.info, "for method '" & branch.name.s &
         "' the `.requires` or `.ensures` properties are incompatible.")
 
-  if branch.typ.lockLevel > disp.typ.lockLevel:
-    when true:
-      message(g.config, branch.info, warnLockLevel,
-        "base method has lock level $1, but dispatcher has $2" %
-          [$branch.typ.lockLevel, $disp.typ.lockLevel])
-    else:
-      # XXX make this an error after bigbreak has been released:
-      localError(g.config, branch.info,
-        "base method has lock level $1, but dispatcher has $2" %
-          [$branch.typ.lockLevel, $disp.typ.lockLevel])
-
 proc setEffectsForProcType*(g: ModuleGraph; t: PType, n: PNode; s: PSym = nil) =
   var effects = t.n[0]
   if t.kind != tyProc or effects.kind != nkEffectList: return
@@ -1592,13 +1523,6 @@ proc trackProc*(c: PContext; s: PSym, body: PNode) =
     s.typ.flags.incl tfGcSafe
   if not t.hasSideEffect and sfSideEffect notin s.flags:
     s.typ.flags.incl tfNoSideEffect
-  if s.typ.lockLevel == UnspecifiedLockLevel:
-    s.typ.lockLevel = t.maxLockLevel
-  elif t.maxLockLevel > s.typ.lockLevel:
-    #localError(s.info,
-    message(g.config, s.info, warnLockLevel,
-      "declared lock level is $1, but real lock level is $2" %
-        [$s.typ.lockLevel, $t.maxLockLevel])
   when defined(drnim):
     if c.graph.strongSemCheck != nil: c.graph.strongSemCheck(c.graph, s, body)
   when defined(useDfa):