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64b0485207
also fixes some instances of using C library functions when there are nim alternatives available
468 lines
15 KiB
Nim
468 lines
15 KiB
Nim
#
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# Nim's Runtime Library
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# (c) Copyright 2016 Andreas Rumpf
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#
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# See the file "copying.txt", included in this
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# distribution, for details about the copyright.
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#
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# "Stack GC" for embedded devices or ultra performance requirements.
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when defined(nimphpext):
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proc roundup(x, v: int): int {.inline.} =
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result = (x + (v-1)) and not (v-1)
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proc emalloc(size: int): pointer {.importc: "_emalloc".}
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proc efree(mem: pointer) {.importc: "_efree".}
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proc osAllocPages(size: int): pointer {.inline.} =
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emalloc(size)
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proc osTryAllocPages(size: int): pointer {.inline.} =
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emalloc(size)
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proc osDeallocPages(p: pointer, size: int) {.inline.} =
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efree(p)
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else:
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include osalloc
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# We manage memory as a thread local stack. Since the allocation pointer
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# is detached from the control flow pointer, this model is vastly more
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# useful than the traditional programming model while almost as safe.
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# Individual objects can also be deleted but no coalescing is performed.
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# Stacks can also be moved from one thread to another.
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# We also support 'finalizers'.
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type
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Finalizer {.compilerproc.} = proc (self: pointer) {.nimcall, benign.}
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# A ref type can have a finalizer that is called before the object's
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# storage is freed.
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AlignType = BiggestFloat
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ObjHeader = object
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typ: PNimType
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nextFinal: ptr ObjHeader # next object with finalizer
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Hole = object # stacks can have holes. Otherwise 'growObj' would be insane.
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zeroTyp: pointer # overlaid with 'typ' field. Always 'nil'.
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size: int # size of the free slot
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Chunk = ptr BaseChunk
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BaseChunk = object
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next: Chunk
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size: int
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head, tail: ptr ObjHeader # first and last object in chunk that
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# has a finalizer attached to it
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type
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StackPtr = object
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bump: pointer
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remaining: int
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current: Chunk
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MemRegion* = object
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remaining: int
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bump: pointer
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head, tail: Chunk
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nextChunkSize, totalSize: int
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hole: ptr Hole # we support individual freeing
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when hasThreadSupport:
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lock: SysLock
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var
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tlRegion {.threadVar.}: MemRegion
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template withRegion*(r: MemRegion; body: untyped) =
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let oldRegion = tlRegion
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tlRegion = r
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try:
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body
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finally:
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tlRegion = oldRegion
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template inc(p: pointer, s: int) =
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p = cast[pointer](cast[int](p) +% s)
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template `+!`(p: pointer, s: int): pointer =
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cast[pointer](cast[int](p) +% s)
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template `-!`(p: pointer, s: int): pointer =
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cast[pointer](cast[int](p) -% s)
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proc allocSlowPath(r: var MemRegion; size: int) =
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# we need to ensure that the underlying linked list
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# stays small. Say we want to grab 16GB of RAM with some
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# exponential growth function. So we allocate 16KB, then
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# 32 KB, 64 KB, 128KB, 256KB, 512KB, 1MB, 2MB, 4MB,
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# 8MB, 16MB, 32MB, 64MB, 128MB, 512MB, 1GB, 2GB, 4GB, 8GB,
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# 16GB --> list contains only 20 elements! That's reasonable.
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if (r.totalSize and 1) == 0:
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r.nextChunkSize =
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if r.totalSize < 64 * 1024: PageSize*4
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else: r.nextChunkSize*2
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var s = roundup(size+sizeof(BaseChunk), PageSize)
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var fresh: Chunk
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if s > r.nextChunkSize:
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fresh = cast[Chunk](osAllocPages(s))
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else:
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fresh = cast[Chunk](osTryAllocPages(r.nextChunkSize))
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if fresh == nil:
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fresh = cast[Chunk](osAllocPages(s))
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# lowest bit in totalSize is the "don't increase nextChunkSize"
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inc r.totalSize
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else:
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s = r.nextChunkSize
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fresh.size = s
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fresh.head = nil
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fresh.tail = nil
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fresh.next = nil
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inc r.totalSize, s
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let old = r.tail
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if old == nil:
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r.head = fresh
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else:
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r.tail.next = fresh
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r.bump = fresh +! sizeof(BaseChunk)
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r.tail = fresh
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r.remaining = s - sizeof(BaseChunk)
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proc alloc(r: var MemRegion; size: int): pointer {.inline.} =
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if size > r.remaining:
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allocSlowPath(r, size)
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sysAssert(size <= r.remaining, "size <= r.remaining")
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dec(r.remaining, size)
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result = r.bump
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inc r.bump, size
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proc runFinalizers(c: Chunk) =
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var it = c.head
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while it != nil:
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# indivually freed objects with finalizer stay in the list, but
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# their typ is nil then:
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if it.typ != nil and it.typ.finalizer != nil:
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(cast[Finalizer](it.typ.finalizer))(it+!sizeof(ObjHeader))
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it = it.nextFinal
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when false:
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proc dealloc(r: var MemRegion; p: pointer) =
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let it = cast[ptr ObjHeader](p-!sizeof(ObjHeader))
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if it.typ != nil and it.typ.finalizer != nil:
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(cast[Finalizer](it.typ.finalizer))(p)
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it.typ = nil
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proc deallocAll(r: var MemRegion; head: Chunk) =
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var it = head
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while it != nil:
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let nxt = it.next
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runFinalizers(it)
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dec r.totalSize, it.size
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osDeallocPages(it, it.size)
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it = nxt
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proc deallocAll*(r: var MemRegion) =
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deallocAll(r, r.head)
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zeroMem(addr r, sizeof r)
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proc obstackPtr*(r: MemRegion): StackPtr =
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result.bump = r.bump
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result.remaining = r.remaining
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result.current = r.tail
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template computeRemaining(r): untyped =
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r.tail.size -% (cast[int](r.bump) -% cast[int](r.tail))
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proc setObstackPtr*(r: var MemRegion; sp: StackPtr) =
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# free everything after 'sp':
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if sp.current != nil:
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deallocAll(r, sp.current.next)
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sp.current.next = nil
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else:
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deallocAll(r, r.head)
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r.head = nil
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r.bump = sp.bump
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r.tail = sp.current
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r.remaining = sp.remaining
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proc obstackPtr*(): StackPtr = tlRegion.obstackPtr()
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proc setObstackPtr*(sp: StackPtr) = tlRegion.setObstackPtr(sp)
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proc deallocAll*() = tlRegion.deallocAll()
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proc deallocOsPages(r: var MemRegion) = r.deallocAll()
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proc joinRegion*(dest: var MemRegion; src: MemRegion) =
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# merging is not hard.
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if dest.head.isNil:
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dest.head = src.head
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else:
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dest.tail.next = src.head
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dest.tail = src.tail
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dest.bump = src.bump
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dest.remaining = src.remaining
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dest.nextChunkSize = max(dest.nextChunkSize, src.nextChunkSize)
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inc dest.totalSize, src.totalSize
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proc isOnHeap*(r: MemRegion; p: pointer): bool =
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# the tail chunk is the largest, so check it first. It's also special
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# in that contains the current bump pointer:
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if r.tail >= p and p < r.bump:
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return true
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var it = r.head
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while it != r.tail:
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if it >= p and p <= it+!it.size: return true
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it = it.next
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when false:
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# essential feature for later: copy data over from one region to another
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proc isInteriorPointer(r: MemRegion; p: pointer): pointer =
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discard " we cannot patch stack pointers anyway!"
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type
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PointerStackChunk = object
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next, prev: ptr PointerStackChunk
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len: int
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data: array[128, pointer]
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template head(s: PointerStackChunk): untyped = s.prev
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template tail(s: PointerStackChunk): untyped = s.next
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include chains
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proc push(r: var MemRegion; s: var PointerStackChunk; x: pointer) =
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if s.len < high(s.data):
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s.data[s.len] = x
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inc s.len
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else:
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let fresh = cast[ptr PointerStackChunk](alloc(r, sizeof(PointerStackChunk)))
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fresh.len = 1
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fresh.data[0] = x
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fresh.next = nil
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fresh.prev = nil
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append(s, fresh)
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proc genericDeepCopyAux(dr: var MemRegion; stack: var PointerStackChunk;
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dest, src: pointer, mt: PNimType) {.benign.}
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proc genericDeepCopyAux(dr: var MemRegion; stack: var PointerStackChunk;
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dest, src: pointer, n: ptr TNimNode) {.benign.} =
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var
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d = cast[ByteAddress](dest)
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s = cast[ByteAddress](src)
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case n.kind
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of nkSlot:
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genericDeepCopyAux(cast[pointer](d +% n.offset),
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cast[pointer](s +% n.offset), n.typ)
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of nkList:
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for i in 0..n.len-1:
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genericDeepCopyAux(dest, src, n.sons[i])
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of nkCase:
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var dd = selectBranch(dest, n)
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var m = selectBranch(src, n)
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# reset if different branches are in use; note different branches also
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# imply that's not self-assignment (``x = x``)!
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if m != dd and dd != nil:
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genericResetAux(dest, dd)
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copyMem(cast[pointer](d +% n.offset), cast[pointer](s +% n.offset),
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n.typ.size)
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if m != nil:
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genericDeepCopyAux(dest, src, m)
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of nkNone: sysAssert(false, "genericDeepCopyAux")
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proc copyDeepString(dr: var MemRegion; stack: var PointerStackChunk; src: NimString): NimString {.inline.} =
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result = rawNewStringNoInit(dr, src.len)
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result.len = src.len
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copyMem(result.data, src.data, src.len + 1)
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proc genericDeepCopyAux(dr: var MemRegion; stack: var PointerStackChunk;
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dest, src: pointer, mt: PNimType) =
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var
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d = cast[ByteAddress](dest)
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s = cast[ByteAddress](src)
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sysAssert(mt != nil, "genericDeepCopyAux 2")
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case mt.kind
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of tyString:
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var x = cast[PPointer](dest)
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var s2 = cast[PPointer](s)[]
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if s2 == nil:
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x[] = nil
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else:
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x[] = copyDeepString(cast[NimString](s2))
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of tySequence:
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var s2 = cast[PPointer](src)[]
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var seq = cast[PGenericSeq](s2)
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var x = cast[PPointer](dest)
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if s2 == nil:
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x[] = nil
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return
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sysAssert(dest != nil, "genericDeepCopyAux 3")
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x[] = newSeq(mt, seq.len)
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var dst = cast[ByteAddress](cast[PPointer](dest)[])
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for i in 0..seq.len-1:
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genericDeepCopyAux(dr, stack,
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cast[pointer](dst +% i*% mt.base.size +% GenericSeqSize),
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cast[pointer](cast[ByteAddress](s2) +% i *% mt.base.size +%
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GenericSeqSize),
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mt.base)
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of tyObject:
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# we need to copy m_type field for tyObject, as it could be empty for
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# sequence reallocations:
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var pint = cast[ptr PNimType](dest)
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pint[] = cast[ptr PNimType](src)[]
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if mt.base != nil:
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genericDeepCopyAux(dr, stack, dest, src, mt.base)
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genericDeepCopyAux(dr, stack, dest, src, mt.node)
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of tyTuple:
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genericDeepCopyAux(dr, stack, dest, src, mt.node)
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of tyArray, tyArrayConstr:
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for i in 0..(mt.size div mt.base.size)-1:
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genericDeepCopyAux(dr, stack,
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cast[pointer](d +% i*% mt.base.size),
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cast[pointer](s +% i*% mt.base.size), mt.base)
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of tyRef:
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let s2 = cast[PPointer](src)[]
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if s2 == nil:
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cast[PPointer](dest)[] = nil
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else:
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# we modify the header of the cell temporarily; instead of the type
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# field we store a forwarding pointer. XXX This is bad when the cloning
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# fails due to OOM etc.
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let x = usrToCell(s2)
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let forw = cast[int](x.typ)
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if (forw and 1) == 1:
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# we stored a forwarding pointer, so let's use that:
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let z = cast[pointer](forw and not 1)
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unsureAsgnRef(cast[PPointer](dest), z)
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else:
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let realType = x.typ
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let z = newObj(realType, realType.base.size)
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unsureAsgnRef(cast[PPointer](dest), z)
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x.typ = cast[PNimType](cast[int](z) or 1)
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genericDeepCopyAux(dr, stack, z, s2, realType.base)
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x.typ = realType
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else:
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copyMem(dest, src, mt.size)
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proc joinAliveDataFromRegion*(dest: var MemRegion; src: var MemRegion;
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root: pointer): pointer =
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# we mark the alive data and copy only alive data over to 'dest'.
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# This is O(liveset) but it nicely compacts memory, so it's fine.
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# We use the 'typ' field as a forwarding pointer. The forwarding
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# pointers have bit 0 set, so we can disambiguate them.
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# We allocate a temporary stack in 'src' that we later free:
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var s: PointerStackChunk
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s.len = 1
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s.data[0] = root
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while s.len > 0:
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var p: pointer
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if s.tail == nil:
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p = s.data[s.len-1]
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dec s.len
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else:
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p = s.tail.data[s.tail.len-1]
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dec s.tail.len
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if s.tail.len == 0:
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unlink(s, s.tail)
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proc rawNewObj(r: var MemRegion, typ: PNimType, size: int): pointer =
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var res = cast[ptr ObjHeader](alloc(r, size + sizeof(ObjHeader)))
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res.typ = typ
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if typ.finalizer != nil:
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res.nextFinal = r.head.head
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r.head.head = res
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result = res +! sizeof(ObjHeader)
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proc newObj(typ: PNimType, size: int): pointer {.compilerRtl.} =
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result = rawNewObj(tlRegion, typ, size)
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zeroMem(result, size)
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when defined(memProfiler): nimProfile(size)
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proc newObjNoInit(typ: PNimType, size: int): pointer {.compilerRtl.} =
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result = rawNewObj(tlRegion, typ, size)
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when defined(memProfiler): nimProfile(size)
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proc newSeq(typ: PNimType, len: int): pointer {.compilerRtl.} =
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let size = addInt(mulInt(len, typ.base.size), GenericSeqSize)
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result = newObj(typ, size)
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cast[PGenericSeq](result).len = len
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cast[PGenericSeq](result).reserved = len
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proc newObjRC1(typ: PNimType, size: int): pointer {.compilerRtl.} =
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result = rawNewObj(tlRegion, typ, size)
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zeroMem(result, size)
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proc newSeqRC1(typ: PNimType, len: int): pointer {.compilerRtl.} =
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let size = addInt(mulInt(len, typ.base.size), GenericSeqSize)
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result = newObj(typ, size)
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cast[PGenericSeq](result).len = len
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cast[PGenericSeq](result).reserved = len
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proc growObj(region: var MemRegion; old: pointer, newsize: int): pointer =
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let typ = cast[ptr ObjHeader](old -! sizeof(ObjHeader)).typ
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result = rawNewObj(region, typ, newsize)
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let elemSize = if typ.kind == tyString: 1 else: typ.base.size
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let oldsize = cast[PGenericSeq](old).len*elemSize + GenericSeqSize
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copyMem(result, old, oldsize)
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zeroMem(result +! oldsize, newsize-oldsize)
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proc growObj(old: pointer, newsize: int): pointer {.rtl.} =
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result = growObj(tlRegion, old, newsize)
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proc unsureAsgnRef(dest: PPointer, src: pointer) {.compilerproc, inline.} =
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dest[] = src
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proc asgnRef(dest: PPointer, src: pointer) {.compilerproc, inline.} =
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dest[] = src
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proc asgnRefNoCycle(dest: PPointer, src: pointer) {.compilerproc, inline.} =
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dest[] = src
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proc alloc(size: Natural): pointer =
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result = c_malloc(size)
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if result == nil: raiseOutOfMem()
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proc alloc0(size: Natural): pointer =
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result = alloc(size)
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zeroMem(result, size)
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proc realloc(p: pointer, newsize: Natural): pointer =
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result = c_realloc(p, newsize)
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if result == nil: raiseOutOfMem()
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proc dealloc(p: pointer) = c_free(p)
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proc alloc0(r: var MemRegion; size: Natural): pointer =
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# ignore the region. That is correct for the channels module
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# but incorrect in general. XXX
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result = alloc0(size)
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proc dealloc(r: var MemRegion; p: pointer) = dealloc(p)
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proc allocShared(size: Natural): pointer =
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result = c_malloc(size)
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if result == nil: raiseOutOfMem()
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proc allocShared0(size: Natural): pointer =
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result = alloc(size)
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zeroMem(result, size)
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proc reallocShared(p: pointer, newsize: Natural): pointer =
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result = c_realloc(p, newsize)
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if result == nil: raiseOutOfMem()
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proc deallocShared(p: pointer) = c_free(p)
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when hasThreadSupport:
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proc getFreeSharedMem(): int = 0
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proc getTotalSharedMem(): int = 0
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proc getOccupiedSharedMem(): int = 0
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proc GC_disable() = discard
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proc GC_enable() = discard
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proc GC_fullCollect() = discard
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proc GC_setStrategy(strategy: GC_Strategy) = discard
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proc GC_enableMarkAndSweep() = discard
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proc GC_disableMarkAndSweep() = discard
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proc GC_getStatistics(): string = return ""
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proc getOccupiedMem(): int =
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result = tlRegion.totalSize - tlRegion.remaining
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proc getFreeMem(): int = tlRegion.remaining
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proc getTotalMem(): int =
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result = tlRegion.totalSize
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proc setStackBottom(theStackBottom: pointer) = discard
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