diff options
Diffstat (limited to 'lib/system/gc.nim')
| -rw-r--r-- | lib/system/gc.nim | 32 |
1 files changed, 17 insertions, 15 deletions
diff --git a/lib/system/gc.nim b/lib/system/gc.nim index b36822aad..9289c7f55 100644 --- a/lib/system/gc.nim +++ b/lib/system/gc.nim @@ -31,7 +31,7 @@ In Nim the compiler cannot always know if a reference is stored on the stack or not. This is caused by var parameters. Consider this example: -.. code-block:: Nim + ```Nim proc setRef(r: var ref TNode) = new(r) @@ -41,11 +41,12 @@ Consider this example: setRef(r) # here we should not update the reference counts, because # r is on the stack setRef(r.left) # here we should update the refcounts! + ``` We have to decide at runtime whether the reference is on the stack or not. The generated code looks roughly like this: -.. code-block:: C + ```C void setref(TNode** ref) { unsureAsgnRef(ref, newObj(TNode_TI, sizeof(TNode))) } @@ -53,6 +54,7 @@ The generated code looks roughly like this: setRef(&r) setRef(&r->left) } + ``` Note that for systems with a continuous stack (which most systems have) the check whether the ref is on the stack is very cheap (only two @@ -76,7 +78,7 @@ when defined(memProfiler): proc nimProfile(requestedSize: int) {.benign.} when hasThreadSupport: - import sharedlist + import std/sharedlist const rcIncrement = 0b1000 # so that lowest 3 bits are not touched @@ -170,11 +172,11 @@ proc addZCT(s: var CellSeq, c: PCell) {.noinline.} = proc cellToUsr(cell: PCell): pointer {.inline.} = # convert object (=pointer to refcount) to pointer to userdata - result = cast[pointer](cast[ByteAddress](cell)+%ByteAddress(sizeof(Cell))) + result = cast[pointer](cast[int](cell)+%ByteAddress(sizeof(Cell))) proc usrToCell(usr: pointer): PCell {.inline.} = # convert pointer to userdata to object (=pointer to refcount) - result = cast[PCell](cast[ByteAddress](usr)-%ByteAddress(sizeof(Cell))) + result = cast[PCell](cast[int](usr)-%ByteAddress(sizeof(Cell))) proc extGetCellType(c: pointer): PNimType {.compilerproc.} = # used for code generation concerning debugging @@ -336,7 +338,7 @@ proc cellsetReset(s: var CellSet) = {.push stacktrace:off.} proc forAllSlotsAux(dest: pointer, n: ptr TNimNode, op: WalkOp) {.benign.} = - var d = cast[ByteAddress](dest) + var d = cast[int](dest) case n.kind of nkSlot: forAllChildrenAux(cast[pointer](d +% n.offset), n.typ, op) of nkList: @@ -356,7 +358,7 @@ proc forAllSlotsAux(dest: pointer, n: ptr TNimNode, op: WalkOp) {.benign.} = of nkNone: sysAssert(false, "forAllSlotsAux") proc forAllChildrenAux(dest: pointer, mt: PNimType, op: WalkOp) = - var d = cast[ByteAddress](dest) + var d = cast[int](dest) if dest == nil: return # nothing to do if ntfNoRefs notin mt.flags: case mt.kind @@ -382,7 +384,7 @@ proc forAllChildren(cell: PCell, op: WalkOp) = of tyRef: # common case forAllChildrenAux(cellToUsr(cell), cell.typ.base, op) of tySequence: - var d = cast[ByteAddress](cellToUsr(cell)) + var d = cast[int](cellToUsr(cell)) var s = cast[PGenericSeq](d) if s != nil: for i in 0..s.len-1: @@ -457,7 +459,7 @@ proc rawNewObj(typ: PNimType, size: int, gch: var GcHeap): pointer = collectCT(gch) var res = cast[PCell](rawAlloc(gch.region, size + sizeof(Cell))) #gcAssert typ.kind in {tyString, tySequence} or size >= typ.base.size, "size too small" - gcAssert((cast[ByteAddress](res) and (MemAlign-1)) == 0, "newObj: 2") + gcAssert((cast[int](res) and (MemAlign-1)) == 0, "newObj: 2") # now it is buffered in the ZCT res.typ = typ setFrameInfo(res) @@ -507,7 +509,7 @@ proc newObjRC1(typ: PNimType, size: int): pointer {.compilerRtl, noinline.} = var res = cast[PCell](rawAlloc(gch.region, size + sizeof(Cell))) sysAssert(allocInv(gch.region), "newObjRC1 after rawAlloc") - sysAssert((cast[ByteAddress](res) and (MemAlign-1)) == 0, "newObj: 2") + sysAssert((cast[int](res) and (MemAlign-1)) == 0, "newObj: 2") # now it is buffered in the ZCT res.typ = typ setFrameInfo(res) @@ -549,9 +551,9 @@ proc growObj(old: pointer, newsize: int, gch: var GcHeap): pointer = var oldsize = align(GenericSeqSize, elemAlign) + cast[PGenericSeq](old).len * elemSize copyMem(res, ol, oldsize + sizeof(Cell)) - zeroMem(cast[pointer](cast[ByteAddress](res) +% oldsize +% sizeof(Cell)), + zeroMem(cast[pointer](cast[int](res) +% oldsize +% sizeof(Cell)), newsize-oldsize) - sysAssert((cast[ByteAddress](res) and (MemAlign-1)) == 0, "growObj: 3") + sysAssert((cast[int](res) and (MemAlign-1)) == 0, "growObj: 3") # This can be wrong for intermediate temps that are nevertheless on the # heap because of lambda lifting: #gcAssert(res.refcount shr rcShift <=% 1, "growObj: 4") @@ -683,7 +685,7 @@ proc collectCycles(gch: var GcHeap) {.raises: [].} = proc gcMark(gch: var GcHeap, p: pointer) {.inline.} = # the addresses are not as cells on the stack, so turn them to cells: sysAssert(allocInv(gch.region), "gcMark begin") - var c = cast[ByteAddress](p) + var c = cast[int](p) if c >% PageSize: # fast check: does it look like a cell? var objStart = cast[PCell](interiorAllocatedPtr(gch.region, p)) @@ -848,10 +850,10 @@ when withRealTime: stack.bottomSaved = stack.bottom when stackIncreases: stack.bottom = cast[pointer]( - cast[ByteAddress](stack.pos) - sizeof(pointer) * 6 - stackSize) + cast[int](stack.pos) - sizeof(pointer) * 6 - stackSize) else: stack.bottom = cast[pointer]( - cast[ByteAddress](stack.pos) + sizeof(pointer) * 6 + stackSize) + cast[int](stack.pos) + sizeof(pointer) * 6 + stackSize) GC_step(gch, us, strongAdvice) |