Merge branch 'devel' into pr_gcc14_action

compiler/sem.nim

@@ -222,66 +222,7 @@ proc shouldCheckCaseCovered(caseTyp: PType): bool =
   else:
     discard
 
-proc endsInNoReturn(n: PNode): bool =
-  ## check if expr ends the block like raising or call of noreturn procs do
-  result = false # assume it does return
-
-  template checkBranch(branch) =
-    if not endsInNoReturn(branch):
-      # proved a branch returns
-      return false
-
-  var it = n
-  # skip these beforehand, no special handling needed
-  while it.kind in {nkStmtList, nkStmtListExpr} and it.len > 0:
-    it = it.lastSon
-
-  case it.kind
-  of nkIfStmt:
-    var hasElse = false
-    for branch in it:
-      checkBranch:
-        if branch.len == 2:
-          branch[1]
-        elif branch.len == 1:
-          hasElse = true
-          branch[0]
-        else:
-          raiseAssert "Malformed `if` statement during endsInNoReturn"
-    # none of the branches returned
-    result = hasElse # Only truly a no-return when it's exhaustive
-  of nkCaseStmt:
-    let caseTyp = skipTypes(it[0].typ, abstractVar-{tyTypeDesc})
-    # semCase should already have checked for exhaustiveness in this case
-    # effectively the same as having an else
-    var hasElse = caseTyp.shouldCheckCaseCovered()
-
-    # actual noreturn checks
-    for i in 1 ..< it.len:
-      let branch = it[i]
-      checkBranch:
-        case branch.kind
-        of nkOfBranch:
-          branch[^1]
-        of nkElifBranch:
-          branch[1]
-        of nkElse:
-          hasElse = true
-          branch[0]
-        else:
-          raiseAssert "Malformed `case` statement in endsInNoReturn"
-    # Can only guarantee a noreturn if there is an else or it's exhaustive
-    result = hasElse
-  of nkTryStmt:
-    checkBranch(it[0])
-    for i in 1 ..< it.len:
-      let branch = it[i]
-      checkBranch(branch[^1])
-    # none of the branches returned
-    result = true
-  else:
-    result = it.kind in nkLastBlockStmts or
-      it.kind in nkCallKinds and it[0].kind == nkSym and sfNoReturn in it[0].sym.flags
+proc endsInNoReturn(n: PNode): bool
 
 proc commonType*(c: PContext; x: PType, y: PNode): PType =
   # ignore exception raising branches in case/if expressions

compiler/semfold.nim

@@ -771,7 +771,8 @@ proc getConstExpr(m: PSym, n: PNode; idgen: IdGenerator; g: ModuleGraph): PNode
   of nkCast:
     var a = getConstExpr(m, n[1], idgen, g)
     if a == nil: return
-    if n.typ != nil and n.typ.kind in NilableTypes:
+    if n.typ != nil and n.typ.kind in NilableTypes and
+        not (n.typ.kind == tyProc and a.typ.kind == tyProc):
       # we allow compile-time 'cast' for pointer types:
       result = a
       result.typ = n.typ

compiler/semstmts.nim

@@ -132,17 +132,140 @@ proc semExprBranchScope(c: PContext, n: PNode; expectedType: PType = nil): PNode
   closeScope(c)
 
 const
-  skipForDiscardable = {nkIfStmt, nkIfExpr, nkCaseStmt, nkOfBranch,
-    nkElse, nkStmtListExpr, nkTryStmt, nkFinally, nkExceptBranch,
+  skipForDiscardable = {nkStmtList, nkStmtListExpr,
+    nkOfBranch, nkElse, nkFinally, nkExceptBranch,
     nkElifBranch, nkElifExpr, nkElseExpr, nkBlockStmt, nkBlockExpr,
     nkHiddenStdConv, nkHiddenDeref}
 
 proc implicitlyDiscardable(n: PNode): bool =
-  var n = n
-  while n.kind in skipForDiscardable: n = n.lastSon
-  result = n.kind in nkLastBlockStmts or
-           (isCallExpr(n) and n[0].kind == nkSym and
-           sfDiscardable in n[0].sym.flags)
+  # same traversal as endsInNoReturn
+  template checkBranch(branch) =
+    if not implicitlyDiscardable(branch):
+      return false
+
+  var it = n
+  # skip these beforehand, no special handling needed
+  while it.kind in skipForDiscardable and it.len > 0:
+    it = it.lastSon
+
+  case it.kind
+  of nkIfExpr, nkIfStmt:
+    for branch in it:
+      checkBranch:
+        if branch.len == 2:
+          branch[1]
+        elif branch.len == 1:
+          branch[0]
+        else:
+          raiseAssert "Malformed `if` statement during implicitlyDiscardable"
+    # all branches are discardable
+    result = true
+  of nkCaseStmt:
+    for i in 1 ..< it.len:
+      let branch = it[i]
+      checkBranch:
+        case branch.kind
+        of nkOfBranch:
+          branch[^1]
+        of nkElifBranch:
+          branch[1]
+        of nkElse:
+          branch[0]
+        else:
+          raiseAssert "Malformed `case` statement in endsInNoReturn"
+    # all branches are discardable
+    result = true
+  of nkTryStmt:
+    checkBranch(it[0])
+    for i in 1 ..< it.len:
+      let branch = it[i]
+      if branch.kind != nkFinally:
+        checkBranch(branch[^1])
+    # all branches are discardable
+    result = true
+  of nkCallKinds:
+    result = it[0].kind == nkSym and {sfDiscardable, sfNoReturn} * it[0].sym.flags != {}
+  of nkLastBlockStmts:
+    result = true
+  else:
+    result = false
+
+proc endsInNoReturn(n: PNode, returningNode: var PNode): bool =
+  ## check if expr ends the block like raising or call of noreturn procs do
+  result = false # assume it does return
+
+  template checkBranch(branch) =
+    if not endsInNoReturn(branch, returningNode):
+      # proved a branch returns
+      return false
+
+  var it = n
+  # skip these beforehand, no special handling needed
+  while it.kind in skipForDiscardable and it.len > 0:
+    it = it.lastSon
+
+  case it.kind
+  of nkIfExpr, nkIfStmt:
+    var hasElse = false
+    for branch in it:
+      checkBranch:
+        if branch.len == 2:
+          branch[1]
+        elif branch.len == 1:
+          hasElse = true
+          branch[0]
+        else:
+          raiseAssert "Malformed `if` statement during endsInNoReturn"
+    # none of the branches returned
+    result = hasElse # Only truly a no-return when it's exhaustive
+  of nkCaseStmt:
+    let caseTyp = skipTypes(it[0].typ, abstractVar-{tyTypeDesc})
+    # semCase should already have checked for exhaustiveness in this case
+    # effectively the same as having an else
+    var hasElse = caseTyp.shouldCheckCaseCovered()
+
+    # actual noreturn checks
+    for i in 1 ..< it.len:
+      let branch = it[i]
+      checkBranch:
+        case branch.kind
+        of nkOfBranch:
+          branch[^1]
+        of nkElifBranch:
+          branch[1]
+        of nkElse:
+          hasElse = true
+          branch[0]
+        else:
+          raiseAssert "Malformed `case` statement in endsInNoReturn"
+    # Can only guarantee a noreturn if there is an else or it's exhaustive
+    result = hasElse
+  of nkTryStmt:
+    checkBranch(it[0])
+    var lastIndex = it.len - 1
+    if it[lastIndex].kind == nkFinally:
+      # if finally is noreturn, then the entire statement is noreturn
+      if endsInNoReturn(it[lastIndex][^1], returningNode):
+        return true
+      dec lastIndex
+    for i in 1 .. lastIndex:
+      let branch = it[i]
+      checkBranch(branch[^1])
+    # none of the branches returned
+    result = true
+  of nkLastBlockStmts:
+    result = true
+  of nkCallKinds:
+    result = it[0].kind == nkSym and sfNoReturn in it[0].sym.flags
+    if not result:
+      returningNode = it
+  else:
+    result = false
+    returningNode = it
+
+proc endsInNoReturn(n: PNode): bool =
+  var dummy: PNode = nil
+  result = endsInNoReturn(n, dummy)
 
 proc fixNilType(c: PContext; n: PNode) =
   if isAtom(n):
@@ -165,13 +288,9 @@ proc discardCheck(c: PContext, result: PNode, flags: TExprFlags) =
         localError(c.config, result.info, "expression has no type: " &
                renderTree(result, {renderNoComments}))
       else:
-        var n = result
-        while n.kind in skipForDiscardable:
-          if n.kind == nkTryStmt: n = n[0]
-          else: n = n.lastSon
-
         # Ignore noreturn procs since they don't have a type
-        if n.endsInNoReturn:
+        var n = result
+        if result.endsInNoReturn(n):
           return
 
         var s = "expression '" & $n & "' is of type '" &

lib/pure/options.nim

@@ -117,9 +117,10 @@ proc option*[T](val: sink T): Option[T] {.inline.} =
     assert option[Foo](nil).isNone
     assert option(42).isSome
 
-  result.val = val
-  when T isnot SomePointer:
-    result.has = true
+  when T is SomePointer:
+    result = Option[T](val: val)
+  else:
+    result = Option[T](has: true, val: val)
 
 proc some*[T](val: sink T): Option[T] {.inline.} =
   ## Returns an `Option` that has the value `val`.
@@ -136,10 +137,9 @@ proc some*[T](val: sink T): Option[T] {.inline.} =
 
   when T is SomePointer:
     assert not val.isNil
-    result.val = val
+    result = Option[T](val: val)
   else:
-    result.has = true
-    result.val = val
+    result = Option[T](has: true, val: val)
 
 proc none*(T: typedesc): Option[T] {.inline.} =
   ## Returns an `Option` for this type that has no value.

lib/std/syncio.nim

@@ -874,7 +874,7 @@ proc writeFile*(filename: string, content: openArray[byte]) {.since: (1, 1).} =
   var f: File = nil
   if open(f, filename, fmWrite):
     try:
-      f.writeBuffer(unsafeAddr content[0], content.len)
+      discard f.writeBuffer(unsafeAddr content[0], content.len)
     finally:
       close(f)
   else:

lib/system/alloc.nim

@@ -93,8 +93,6 @@ type
     freeList: ptr FreeCell
     free: int            # how many bytes remain
     acc: int             # accumulator for small object allocation
-    when defined(gcDestructors):
-      sharedFreeList: ptr FreeCell # make no attempt at avoiding false sharing for now for this object field
     data {.align: MemAlign.}: UncheckedArray[byte]      # start of usable memory
 
   BigChunk = object of BaseChunk # not necessarily > PageSize!
@@ -109,7 +107,9 @@ type
   MemRegion = object
     when not defined(gcDestructors):
       minLargeObj, maxLargeObj: int
-    freeSmallChunks: array[0..max(1,SmallChunkSize div MemAlign-1), PSmallChunk]
+    freeSmallChunks: array[0..max(1, SmallChunkSize div MemAlign-1), PSmallChunk]
+    when defined(gcDestructors):
+      sharedFreeLists: array[0..max(1, SmallChunkSize div MemAlign-1), ptr FreeCell]
     flBitmap: uint32
     slBitmap: array[RealFli, uint32]
     matrix: array[RealFli, array[MaxSli, PBigChunk]]
@@ -777,8 +777,10 @@ when defined(gcDestructors):
     sysAssert c.next == nil, "c.next pointer must be nil"
     atomicPrepend a.sharedFreeListBigChunks, c
 
-  proc addToSharedFreeList(c: PSmallChunk; f: ptr FreeCell) {.inline.} =
-    atomicPrepend c.sharedFreeList, f
+  proc addToSharedFreeList(c: PSmallChunk; f: ptr FreeCell; size: int) {.inline.} =
+    atomicPrepend c.owner.sharedFreeLists[size], f
+
+  const MaxSteps = 20
 
   proc compensateCounters(a: var MemRegion; c: PSmallChunk; size: int) =
     # rawDealloc did NOT do the usual:
@@ -788,30 +790,26 @@ when defined(gcDestructors):
     # we split the list in order to achieve bounded response times.
     var it = c.freeList
     var x = 0
-    var maxIters = 20 # make it time-bounded
     while it != nil:
-      if maxIters == 0:
-        let rest = it.next.loada
-        if rest != nil:
-          it.next.storea nil
-          addToSharedFreeList(c, rest)
-        break
       inc x, size
-      it = it.next.loada
-      dec maxIters
-    inc(c.free, x)
+      let chunk = cast[PSmallChunk](pageAddr(it))
+      inc(chunk.free, x)
+      it = it.next
     dec(a.occ, x)
 
   proc freeDeferredObjects(a: var MemRegion; root: PBigChunk) =
     var it = root
-    var maxIters = 20 # make it time-bounded
+    var maxIters = MaxSteps # make it time-bounded
     while true:
+      let rest = it.next.loada
+      it.next.storea nil
+      deallocBigChunk(a, cast[PBigChunk](it))
       if maxIters == 0:
-        let rest = it.next.loada
-        it.next.storea nil
-        addToSharedFreeListBigChunks(a, rest)
+        if rest != nil:
+          addToSharedFreeListBigChunks(a, rest)
+          sysAssert a.sharedFreeListBigChunks != nil, "re-enqueing failed"
         break
-      it = it.next.loada
+      it = rest
       dec maxIters
       if it == nil: break
 
@@ -835,8 +833,6 @@ proc rawAlloc(a: var MemRegion, requestedSize: int): pointer =
       sysAssert c.size == PageSize, "rawAlloc 3"
       c.size = size
       c.acc = size
-      when defined(gcDestructors):
-        c.sharedFreeList = nil
       c.free = SmallChunkSize - smallChunkOverhead() - size
       sysAssert c.owner == addr(a), "rawAlloc: No owner set!"
       c.next = nil
@@ -853,10 +849,11 @@ proc rawAlloc(a: var MemRegion, requestedSize: int): pointer =
       when defined(gcDestructors):
         if c.freeList == nil:
           when hasThreadSupport:
-            c.freeList = atomicExchangeN(addr c.sharedFreeList, nil, ATOMIC_RELAXED)
+            # Steal the entire list from `sharedFreeList`:
+            c.freeList = atomicExchangeN(addr a.sharedFreeLists[s], nil, ATOMIC_RELAXED)
           else:
-            c.freeList = c.sharedFreeList
-            c.sharedFreeList = nil
+            c.freeList = a.sharedFreeLists[s]
+            a.sharedFreeLists[s] = nil
           compensateCounters(a, c, size)
       if c.freeList == nil:
         sysAssert(c.acc + smallChunkOverhead() + size <= SmallChunkSize,
@@ -923,7 +920,7 @@ proc rawDealloc(a: var MemRegion, p: pointer) =
   if isSmallChunk(c):
     # `p` is within a small chunk:
     var c = cast[PSmallChunk](c)
-    var s = c.size
+    let s = c.size
     #       ^ We might access thread foreign storage here.
     # The other thread cannot possibly free this block as it's still alive.
     var f = cast[ptr FreeCell](p)
@@ -957,7 +954,7 @@ proc rawDealloc(a: var MemRegion, p: pointer) =
           freeBigChunk(a, cast[PBigChunk](c))
     else:
       when defined(gcDestructors):
-        addToSharedFreeList(c, f)
+        addToSharedFreeList(c, f, s div MemAlign)
     sysAssert(((cast[int](p) and PageMask) - smallChunkOverhead()) %%
                s == 0, "rawDealloc 2")
   else: