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Nim/lib/system/gc_common.nim
Yuriy Glukhov 73387e89a0 Fixed compilation error (#5462)
2017-03-02 14:58:26 +01:00

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Nim
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#
#
# Nim's Runtime Library
# (c) Copyright 2015 Rokas Kupstys
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
type
ForeignCell* = object
data*: pointer
owner: ptr GcHeap
proc protect*(x: pointer): ForeignCell =
nimGCref(x)
result.data = x
result.owner = addr(gch)
when defined(nimTypeNames):
proc dumpNumberOfInstances* =
var it = nimTypeRoot
while it != nil:
if it.instances > 0:
c_fprintf(stdout, "[Heap] %s: #%ld; bytes: %ld\n", it.name, it.instances, it.sizes)
it = it.nextType
template decTypeSize(cell, t) =
# XXX this needs to use atomics for multithreaded apps!
when defined(nimTypeNames):
if t.kind in {tyString, tySequence}:
let len = cast[PGenericSeq](cellToUsr(cell)).len
let base = if t.kind == tyString: 1 else: t.base.size
let size = addInt(mulInt(len, base), GenericSeqSize)
dec t.sizes, size+sizeof(Cell)
else:
dec t.sizes, t.size+sizeof(Cell)
dec t.instances
template incTypeSize(typ, size) =
when defined(nimTypeNames):
inc typ.instances
inc typ.sizes, size+sizeof(Cell)
proc dispose*(x: ForeignCell) =
when hasThreadSupport:
# if we own it we can free it directly:
if x.owner == addr(gch):
nimGCunref(x.data)
else:
x.owner.toDispose.add(x.data)
else:
nimGCunref(x.data)
proc isNotForeign*(x: ForeignCell): bool =
## returns true if 'x' belongs to the calling thread.
## No deep copy has to be performed then.
x.owner == addr(gch)
when nimCoroutines:
iterator items(first: var GcStack): ptr GcStack =
var item = addr(first)
while true:
yield item
item = item.next
if item == addr(first):
break
proc append(first: var GcStack, stack: ptr GcStack) =
## Append stack to the ring of stacks.
first.prev.next = stack
stack.prev = first.prev
first.prev = stack
stack.next = addr(first)
proc append(first: var GcStack): ptr GcStack =
## Allocate new GcStack object, append it to the ring of stacks and return it.
result = cast[ptr GcStack](alloc0(sizeof(GcStack)))
first.append(result)
proc remove(first: var GcStack, stack: ptr GcStack) =
## Remove stack from ring of stacks.
gcAssert(addr(first) != stack, "Main application stack can not be removed")
if addr(first) == stack or stack == nil:
return
stack.prev.next = stack.next
stack.next.prev = stack.prev
dealloc(stack)
proc remove(stack: ptr GcStack) =
gch.stack.remove(stack)
proc find(first: var GcStack, bottom: pointer): ptr GcStack =
## Find stack struct based on bottom pointer. If `bottom` is nil then main
## thread stack is is returned.
if bottom == nil:
return addr(gch.stack)
for stack in first.items():
if stack.bottom == bottom:
return stack
proc len(stack: var GcStack): int =
for _ in stack.items():
result = result + 1
else:
# This iterator gets optimized out in forEachStackSlot().
iterator items(first: var GcStack): ptr GcStack = yield addr(first)
proc len(stack: var GcStack): int = 1
proc stackSize(stack: ptr GcStack): int {.noinline.} =
when nimCoroutines:
var pos = stack.pos
else:
var pos {.volatile.}: pointer
pos = addr(pos)
if pos != nil:
when defined(stackIncreases):
result = cast[ByteAddress](pos) -% cast[ByteAddress](stack.bottom)
else:
result = cast[ByteAddress](stack.bottom) -% cast[ByteAddress](pos)
else:
result = 0
proc stackSize(): int {.noinline.} =
for stack in gch.stack.items():
result = result + stack.stackSize()
when nimCoroutines:
proc setPosition(stack: ptr GcStack, position: pointer) =
stack.pos = position
stack.maxStackSize = max(stack.maxStackSize, stack.stackSize())
proc setPosition(stack: var GcStack, position: pointer) =
setPosition(addr(stack), position)
proc getActiveStack(gch: var GcHeap): ptr GcStack =
return gch.activeStack
proc isActiveStack(stack: ptr GcStack): bool =
return gch.activeStack == stack
else:
# Stack positions do not need to be tracked if coroutines are not used.
proc setPosition(stack: ptr GcStack, position: pointer) = discard
proc setPosition(stack: var GcStack, position: pointer) = discard
# There is just one stack - main stack of the thread. It is active always.
proc getActiveStack(gch: var GcHeap): ptr GcStack = addr(gch.stack)
proc isActiveStack(stack: ptr GcStack): bool = true
when declared(threadType):
proc setupForeignThreadGc*() {.gcsafe.} =
## Call this if you registered a callback that will be run from a thread not
## under your control. This has a cheap thread-local guard, so the GC for
## this thread will only be initialized once per thread, no matter how often
## it is called.
##
## This function is available only when ``--threads:on`` and ``--tlsEmulation:off``
## switches are used
if threadType == ThreadType.None:
initAllocator()
var stackTop {.volatile.}: pointer
setStackBottom(addr(stackTop))
initGC()
threadType = ThreadType.ForeignThread
proc tearDownForeignThreadGc*() {.gcsafe.} =
## Call this to tear down the GC, previously initialized by ``setupForeignThreadGc``.
## If GC has not been previously initialized, or has already been torn down, the
## call does nothing.
##
## This function is available only when ``--threads:on`` and ``--tlsEmulation:off``
## switches are used
if threadType != ThreadType.ForeignThread:
return
when declared(deallocOsPages): deallocOsPages()
threadType = ThreadType.None
when declared(gch): zeroMem(addr gch, sizeof(gch))
else:
template setupForeignThreadGc*() =
{.error: "setupForeignThreadGc is available only when ``--threads:on`` and ``--tlsEmulation:off`` are used".}
template tearDownForeignThreadGc*() =
{.error: "tearDownForeignThreadGc is available only when ``--threads:on`` and ``--tlsEmulation:off`` are used".}
# ----------------- stack management --------------------------------------
# inspired from Smart Eiffel
when defined(emscripten):
const stackIncreases = true
elif defined(sparc):
const stackIncreases = false
elif defined(hppa) or defined(hp9000) or defined(hp9000s300) or
defined(hp9000s700) or defined(hp9000s800) or defined(hp9000s820):
const stackIncreases = true
else:
const stackIncreases = false
{.push stack_trace: off.}
when nimCoroutines:
proc GC_addStack(bottom: pointer) {.cdecl, exportc.} =
# c_fprintf(stdout, "GC_addStack: %p;\n", bottom)
var stack = gch.stack.append()
stack.bottom = bottom
stack.setPosition(bottom)
proc GC_removeStack(bottom: pointer) {.cdecl, exportc.} =
# c_fprintf(stdout, "GC_removeStack: %p;\n", bottom)
gch.stack.find(bottom).remove()
proc GC_setActiveStack(bottom: pointer) {.cdecl, exportc.} =
## Sets active stack and updates current stack position.
# c_fprintf(stdout, "GC_setActiveStack: %p;\n", bottom)
var sp {.volatile.}: pointer
gch.activeStack = gch.stack.find(bottom)
gch.activeStack.setPosition(addr(sp))
when not defined(useNimRtl):
proc setStackBottom(theStackBottom: pointer) =
# Initializes main stack of the thread.
when nimCoroutines:
if gch.stack.next == nil:
# Main stack was not initialized yet
gch.stack.next = addr(gch.stack)
gch.stack.prev = addr(gch.stack)
gch.stack.bottom = theStackBottom
gch.stack.maxStackSize = 0
gch.activeStack = addr(gch.stack)
if gch.stack.bottom == nil:
# This branch will not be called when -d:nimCoroutines - it is fine,
# because same thing is done just above.
#c_fprintf(stdout, "stack bottom: %p;\n", theStackBottom)
# the first init must be the one that defines the stack bottom:
gch.stack.bottom = theStackBottom
elif theStackBottom != gch.stack.bottom:
var a = cast[ByteAddress](theStackBottom) # and not PageMask - PageSize*2
var b = cast[ByteAddress](gch.stack.bottom)
#c_fprintf(stdout, "old: %p new: %p;\n",gch.stack.bottom,theStackBottom)
when stackIncreases:
gch.stack.bottom = cast[pointer](min(a, b))
else:
gch.stack.bottom = cast[pointer](max(a, b))
gch.stack.setPosition(theStackBottom)
{.pop.}
proc isOnStack(p: pointer): bool =
var stackTop {.volatile.}: pointer
stackTop = addr(stackTop)
var a = cast[ByteAddress](gch.getActiveStack().bottom)
var b = cast[ByteAddress](stackTop)
when not stackIncreases:
swap(a, b)
var x = cast[ByteAddress](p)
result = a <=% x and x <=% b
when defined(sparc): # For SPARC architecture.
when nimCoroutines:
{.error: "Nim coroutines are not supported on this platform."}
template forEachStackSlot(gch, gcMark: untyped) {.dirty.} =
when defined(sparcv9):
asm """"flushw \n" """
else:
asm """"ta 0x3 ! ST_FLUSH_WINDOWS\n" """
var
max = gch.stack.bottom
sp: PPointer
stackTop: array[0..1, pointer]
sp = addr(stackTop[0])
# Addresses decrease as the stack grows.
while sp <= max:
gcMark(gch, sp[])
sp = cast[PPointer](cast[ByteAddress](sp) +% sizeof(pointer))
elif defined(ELATE):
{.error: "stack marking code is to be written for this architecture".}
elif stackIncreases:
# ---------------------------------------------------------------------------
# Generic code for architectures where addresses increase as the stack grows.
# ---------------------------------------------------------------------------
var
jmpbufSize {.importc: "sizeof(jmp_buf)", nodecl.}: int
# a little hack to get the size of a JmpBuf in the generated C code
# in a platform independent way
template forEachStackSlot(gch, gcMark: untyped) {.dirty.} =
var registers {.noinit.}: C_JmpBuf
if c_setjmp(registers) == 0'i32: # To fill the C stack with registers.
for stack in gch.stack.items():
var max = cast[ByteAddress](gch.stack.bottom)
var sp = cast[ByteAddress](addr(registers)) -% sizeof(pointer)
while sp >=% max:
gcMark(gch, cast[PPointer](sp)[])
sp = sp -% sizeof(pointer)
else:
# ---------------------------------------------------------------------------
# Generic code for architectures where addresses decrease as the stack grows.
# ---------------------------------------------------------------------------
template forEachStackSlot(gch, gcMark: untyped) {.dirty.} =
# We use a jmp_buf buffer that is in the C stack.
# Used to traverse the stack and registers assuming
# that 'setjmp' will save registers in the C stack.
type PStackSlice = ptr array[0..7, pointer]
var registers {.noinit.}: C_JmpBuf
# Update position of stack gc is executing in.
gch.getActiveStack().setPosition(addr(registers))
if c_setjmp(registers) == 0'i32: # To fill the C stack with registers.
for stack in gch.stack.items():
var max = cast[ByteAddress](stack.bottom)
var sp = cast[ByteAddress](addr(registers))
when defined(amd64):
if stack.isActiveStack():
# words within the jmp_buf structure may not be properly aligned.
let regEnd = sp +% sizeof(registers)
while sp <% regEnd:
gcMark(gch, cast[PPointer](sp)[])
gcMark(gch, cast[PPointer](sp +% sizeof(pointer) div 2)[])
sp = sp +% sizeof(pointer)
# Make sure sp is word-aligned
sp = sp and not (sizeof(pointer) - 1)
# loop unrolled:
while sp <% max - 8*sizeof(pointer):
gcMark(gch, cast[PStackSlice](sp)[0])
gcMark(gch, cast[PStackSlice](sp)[1])
gcMark(gch, cast[PStackSlice](sp)[2])
gcMark(gch, cast[PStackSlice](sp)[3])
gcMark(gch, cast[PStackSlice](sp)[4])
gcMark(gch, cast[PStackSlice](sp)[5])
gcMark(gch, cast[PStackSlice](sp)[6])
gcMark(gch, cast[PStackSlice](sp)[7])
sp = sp +% sizeof(pointer)*8
# last few entries:
while sp <=% max:
gcMark(gch, cast[PPointer](sp)[])
sp = sp +% sizeof(pointer)
# ----------------------------------------------------------------------------
# end of non-portable code
# ----------------------------------------------------------------------------
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