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|
#
#
# The Nim Compiler
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## code owner: Arne Döring
## e-mail: arne.doering@gmx.net
## included from types.nim
proc align(address, alignment: BiggestInt): BiggestInt =
result = (address + (alignment - 1)) and not (alignment - 1)
proc align(address, alignment: int32): int32 =
result = (address + (alignment - 1)) and not (alignment - 1)
const
## a size is considered "unknown" when it is an imported type from C
## or C++.
szUnknownSize* = -3
szIllegalRecursion* = -2
szUncomputedSize* = -1
szTooBigSize* = -4
type IllegalTypeRecursionError = object of ValueError
proc raiseIllegalTypeRecursion() =
raise newException(IllegalTypeRecursionError, "illegal type recursion")
type
OffsetAccum* = object
maxAlign*: int32
offset*: int32
proc inc*(arg: var OffsetAccum; value: int32) =
if unlikely(value == szIllegalRecursion): raiseIllegalTypeRecursion()
if value == szUnknownSize or arg.offset == szUnknownSize:
arg.offset = szUnknownSize
else:
arg.offset += value
proc alignmentMax(a, b: int32): int32 =
if unlikely(a == szIllegalRecursion or b == szIllegalRecursion): raiseIllegalTypeRecursion()
if a == szUnknownSize or b == szUnknownSize:
szUnknownSize
else:
max(a, b)
proc align*(arg: var OffsetAccum; value: int32) =
if unlikely(value == szIllegalRecursion): raiseIllegalTypeRecursion()
if value == szUnknownSize or arg.maxAlign == szUnknownSize or arg.offset == szUnknownSize:
arg.maxAlign = szUnknownSize
arg.offset = szUnknownSize
else:
arg.maxAlign = max(value, arg.maxAlign)
arg.offset = align(arg.offset, value)
proc mergeBranch(arg: var OffsetAccum; value: OffsetAccum) =
if value.maxAlign == szUnknownSize or arg.maxAlign == szUnknownSize or
value.offset == szUnknownSize or arg.offset == szUnknownSize:
arg.maxAlign = szUnknownSize
arg.offset = szUnknownSize
else:
arg.offset = max(arg.offset, value.offset)
arg.maxAlign = max(arg.maxAlign, value.maxAlign)
proc finish(arg: var OffsetAccum): int32 =
if arg.maxAlign == szUnknownSize or arg.offset == szUnknownSize:
result = szUnknownSize
arg.offset = szUnknownSize
else:
result = align(arg.offset, arg.maxAlign) - arg.offset
arg.offset += result
proc computeSizeAlign*(conf: ConfigRef; typ: PType)
proc computeSubObjectAlign(conf: ConfigRef; n: PNode): BiggestInt =
## returns object alignment
case n.kind
of nkRecCase:
assert(n[0].kind == nkSym)
result = computeSubObjectAlign(conf, n[0])
for i in 1..<n.len:
let child = n[i]
case child.kind
of nkOfBranch, nkElse:
let align = computeSubObjectAlign(conf, child.lastSon)
if align < 0:
return align
result = max(result, align)
else:
internalError(conf, "computeSubObjectAlign")
of nkRecList:
result = 1
for i, child in n.sons:
let align = computeSubObjectAlign(conf, n[i])
if align < 0:
return align
result = max(result, align)
of nkSym:
computeSizeAlign(conf, n.sym.typ)
result = n.sym.typ.align
else:
result = 1
proc setOffsetsToUnknown(n: PNode) =
if n.kind == nkSym and n.sym.kind == skField:
n.sym.offset = szUnknownSize
else:
for i in 0..<n.safeLen:
setOffsetsToUnknown(n[i])
proc computeObjectOffsetsFoldFunction(conf: ConfigRef; n: PNode; packed: bool; accum: var OffsetAccum) =
## ``offset`` is the offset within the object, after the node has been written, no padding bytes added
## ``align`` maximum alignment from all sub nodes
assert n != nil
if n.typ != nil and n.typ.size == szIllegalRecursion:
raiseIllegalTypeRecursion()
case n.kind
of nkRecCase:
assert(n[0].kind == nkSym)
computeObjectOffsetsFoldFunction(conf, n[0], packed, accum)
var maxChildAlign = if accum.offset == szUnknownSize: szUnknownSize.int32 else: 1'i32
if not packed:
for i in 1..<n.len:
let child = n[i]
case child.kind
of nkOfBranch, nkElse:
# offset parameter cannot be known yet, it needs to know the alignment first
let align = int32(computeSubObjectAlign(conf, n[i].lastSon))
maxChildAlign = alignmentMax(maxChildAlign, align)
else:
internalError(conf, "computeObjectOffsetsFoldFunction(record case branch)")
if maxChildAlign == szUnknownSize:
setOffsetsToUnknown(n)
accum.offset = szUnknownSize
accum.maxAlign = szUnknownSize
else:
# the union needs to be aligned first, before the offsets can be assigned
accum.align(maxChildAlign)
let accumRoot = accum # copy, because each branch should start af the same offset
for i in 1..<n.len:
var branchAccum = OffsetAccum(offset: accumRoot.offset, maxAlign: 1)
computeObjectOffsetsFoldFunction(conf, n[i].lastSon, packed, branchAccum)
discard finish(branchAccum)
accum.mergeBranch(branchAccum)
of nkRecList:
for i, child in n.sons:
computeObjectOffsetsFoldFunction(conf, child, packed, accum)
of nkSym:
var size = szUnknownSize.int32
var align = szUnknownSize.int32
if n.sym.bitsize == 0: # 0 represents bitsize not set
computeSizeAlign(conf, n.sym.typ)
size = n.sym.typ.size.int32
align = if packed: 1 else: n.sym.typ.align.int32
accum.align(align)
if n.sym.alignment > 0:
accum.align(n.sym.alignment.int32)
n.sym.offset = accum.offset
accum.inc(size)
else:
accum.maxAlign = szUnknownSize
accum.offset = szUnknownSize
proc computeUnionObjectOffsetsFoldFunction(conf: ConfigRef; n: PNode; packed: bool; accum: var OffsetAccum) =
## ``accum.offset`` will the offset from the larget member of the union.
case n.kind
of nkRecCase:
accum.offset = szUnknownSize
accum.maxAlign = szUnknownSize
localError(conf, n.info, "Illegal use of ``case`` in union type.")
of nkRecList:
let accumRoot = accum # copy, because each branch should start af the same offset
for child in n.sons:
var branchAccum = OffsetAccum(offset: accumRoot.offset, maxAlign: 1)
computeUnionObjectOffsetsFoldFunction(conf, child, packed, branchAccum)
discard finish(branchAccum)
accum.mergeBranch(branchAccum)
of nkSym:
var size = szUnknownSize.int32
var align = szUnknownSize.int32
if n.sym.bitsize == 0: # 0 represents bitsize not set
computeSizeAlign(conf, n.sym.typ)
size = n.sym.typ.size.int32
align = if packed: 1 else: n.sym.typ.align.int32
accum.align(align)
if n.sym.alignment > 0:
accum.align(n.sym.alignment.int32)
n.sym.offset = accum.offset
accum.inc(size)
else:
accum.maxAlign = szUnknownSize
accum.offset = szUnknownSize
proc computeSizeAlign(conf: ConfigRef; typ: PType) =
template setSize(typ, s) =
typ.size = s
typ.align = s
typ.paddingAtEnd = 0
## computes and sets ``size`` and ``align`` members of ``typ``
assert typ != nil
let hasSize = typ.size != szUncomputedSize
let hasAlign = typ.align != szUncomputedSize
if hasSize and hasAlign:
# nothing to do, size and align already computed
return
# This function can only calculate both, size and align at the same time.
# If one of them is already set this value is stored here and reapplied
let revertSize = typ.size
let revertAlign = typ.align
defer:
if hasSize:
typ.size = revertSize
if hasAlign:
typ.align = revertAlign
if typ.size == szIllegalRecursion or typ.align == szIllegalRecursion:
# we are already computing the size of the type
# --> illegal recursion in type
return
# mark computation in progress
typ.size = szIllegalRecursion
typ.align = szIllegalRecursion
typ.paddingAtEnd = 0
var tk = typ.kind
case tk
of tyProc:
if typ.callConv == ccClosure:
typ.size = 2 * conf.target.ptrSize
else:
typ.size = conf.target.ptrSize
typ.align = int16(conf.target.ptrSize)
of tyNil:
typ.size = conf.target.ptrSize
typ.align = int16(conf.target.ptrSize)
of tyString:
if optSeqDestructors in conf.globalOptions:
typ.size = conf.target.ptrSize * 2
else:
typ.size = conf.target.ptrSize
typ.align = int16(conf.target.ptrSize)
of tyCstring, tySequence, tyPtr, tyRef, tyVar, tyLent:
let base = typ.last
if base == typ:
# this is not the correct location to detect ``type A = ptr A``
typ.size = szIllegalRecursion
typ.align = szIllegalRecursion
typ.paddingAtEnd = szIllegalRecursion
return
typ.align = int16(conf.target.ptrSize)
if typ.kind == tySequence and optSeqDestructors in conf.globalOptions:
typ.size = conf.target.ptrSize * 2
else:
typ.size = conf.target.ptrSize
of tyArray:
computeSizeAlign(conf, typ.elementType)
let elemSize = typ.elementType.size
let len = lengthOrd(conf, typ.indexType)
if elemSize < 0:
typ.size = elemSize
typ.align = int16(elemSize)
elif len < 0:
typ.size = szUnknownSize
typ.align = szUnknownSize
else:
typ.size = toInt64Checked(len * int32(elemSize), szTooBigSize)
typ.align = typ.elementType.align
of tyUncheckedArray:
let base = typ.last
computeSizeAlign(conf, base)
typ.size = 0
typ.align = base.align
of tyEnum:
if firstOrd(conf, typ) < Zero:
typ.size = 4 # use signed int32
typ.align = 4
else:
let lastOrd = toInt64(lastOrd(conf, typ)) # BUGFIX: use lastOrd!
if lastOrd < `shl`(1, 8):
typ.size = 1
typ.align = 1
elif lastOrd < `shl`(1, 16):
typ.size = 2
typ.align = 2
elif lastOrd < `shl`(BiggestInt(1), 32):
typ.size = 4
typ.align = 4
else:
typ.size = 8
typ.align = int16(conf.floatInt64Align)
of tySet:
if typ.elementType.kind == tyGenericParam:
typ.size = szUncomputedSize
typ.align = szUncomputedSize
else:
let length = toInt64(lengthOrd(conf, typ.elementType))
if length <= 8:
typ.size = 1
typ.align = 1
elif length <= 16:
typ.size = 2
typ.align = 2
elif length <= 32:
typ.size = 4
typ.align = 4
elif length <= 64:
typ.size = 8
typ.align = int16(conf.floatInt64Align)
elif align(length, 8) mod 8 == 0:
typ.size = align(length, 8) div 8
typ.align = 1
else:
typ.size = align(length, 8) div 8 + 1
typ.align = 1
of tyRange:
computeSizeAlign(conf, typ.elementType)
typ.size = typ.elementType.size
typ.align = typ.elementType.align
typ.paddingAtEnd = typ.elementType.paddingAtEnd
of tyTuple:
try:
var accum = OffsetAccum(maxAlign: 1)
for i, child in typ.ikids:
computeSizeAlign(conf, child)
accum.align(child.align)
if typ.n != nil: # is named tuple (has field symbols)?
let sym = typ.n[i].sym
sym.offset = accum.offset
accum.inc(int32(child.size))
typ.paddingAtEnd = int16(accum.finish())
typ.size = if accum.offset == 0: 1 else: accum.offset
typ.align = int16(accum.maxAlign)
except IllegalTypeRecursionError:
typ.paddingAtEnd = szIllegalRecursion
typ.size = szIllegalRecursion
typ.align = szIllegalRecursion
of tyObject:
try:
var accum =
if typ.baseClass != nil:
# compute header size
var st = typ.baseClass
while st.kind in skipPtrs:
st = st.skipModifier
computeSizeAlign(conf, st)
if conf.backend == backendCpp:
OffsetAccum(
offset: int32(st.size) - int32(st.paddingAtEnd),
maxAlign: st.align
)
else:
OffsetAccum(
offset: int32(st.size),
maxAlign: st.align
)
elif isObjectWithTypeFieldPredicate(typ):
# this branch is taken for RootObj
OffsetAccum(
offset: conf.target.intSize.int32,
maxAlign: conf.target.intSize.int32
)
else:
OffsetAccum(maxAlign: 1)
if tfUnion in typ.flags:
if accum.offset != 0:
let info = if typ.sym != nil: typ.sym.info else: unknownLineInfo
localError(conf, info, "union type may not have an object header")
accum = OffsetAccum(offset: szUnknownSize, maxAlign: szUnknownSize)
else:
computeUnionObjectOffsetsFoldFunction(conf, typ.n, tfPacked in typ.flags, accum)
elif tfPacked in typ.flags:
accum.maxAlign = 1
computeObjectOffsetsFoldFunction(conf, typ.n, true, accum)
else:
if typ.baseClass == nil and lacksMTypeField(typ) and typ.n.len == 1 and
typ.n[0].kind == nkSym and
typ.n[0].sym.typ.skipTypes(abstractInst).kind == tyUncheckedArray:
# a dummy field is generated for an object with a single field
# with an UncheckedArray type
assert accum.offset == 0
accum.offset = 1
computeObjectOffsetsFoldFunction(conf, typ.n, false, accum)
let paddingAtEnd = int16(accum.finish())
if typ.sym != nil and
typ.sym.flags * {sfCompilerProc, sfImportc} == {sfImportc} and
tfCompleteStruct notin typ.flags:
typ.size = szUnknownSize
typ.align = szUnknownSize
typ.paddingAtEnd = szUnknownSize
else:
typ.size = if accum.offset == 0: 1 else: accum.offset
typ.align = int16(accum.maxAlign)
typ.paddingAtEnd = paddingAtEnd
except IllegalTypeRecursionError:
typ.size = szIllegalRecursion
typ.align = szIllegalRecursion
typ.paddingAtEnd = szIllegalRecursion
of tyInferred:
if typ.hasElementType:
computeSizeAlign(conf, typ.last)
typ.size = typ.last.size
typ.align = typ.last.align
typ.paddingAtEnd = typ.last.paddingAtEnd
of tyGenericInst, tyDistinct, tyGenericBody, tyAlias, tySink, tyOwned:
computeSizeAlign(conf, typ.skipModifier)
typ.size = typ.skipModifier.size
typ.align = typ.skipModifier.align
typ.paddingAtEnd = typ.last.paddingAtEnd
of tyTypeClasses:
if typ.isResolvedUserTypeClass:
computeSizeAlign(conf, typ.last)
typ.size = typ.last.size
typ.align = typ.last.align
typ.paddingAtEnd = typ.last.paddingAtEnd
else:
typ.size = szUnknownSize
typ.align = szUnknownSize
typ.paddingAtEnd = szUnknownSize
of tyTypeDesc:
computeSizeAlign(conf, typ.base)
typ.size = typ.base.size
typ.align = typ.base.align
typ.paddingAtEnd = typ.base.paddingAtEnd
of tyForward:
typ.size = szUnknownSize
typ.align = szUnknownSize
typ.paddingAtEnd = szUnknownSize
of tyStatic:
if typ.n != nil:
computeSizeAlign(conf, typ.last)
typ.size = typ.last.size
typ.align = typ.last.align
typ.paddingAtEnd = typ.last.paddingAtEnd
else:
typ.size = szUnknownSize
typ.align = szUnknownSize
typ.paddingAtEnd = szUnknownSize
of tyInt, tyUInt:
setSize typ, conf.target.intSize.int16
of tyBool, tyChar, tyUInt8, tyInt8:
setSize typ, 1
of tyInt16, tyUInt16:
setSize typ, 2
of tyInt32, tyUInt32, tyFloat32:
setSize typ, 4
of tyInt64, tyUInt64, tyFloat64, tyFloat:
setSize typ, 8
else:
typ.size = szUnknownSize
typ.align = szUnknownSize
typ.paddingAtEnd = szUnknownSize
template foldSizeOf*(conf: ConfigRef; n: PNode; fallback: PNode): PNode =
let config = conf
let node = n
let typ = node[1].typ
computeSizeAlign(config, typ)
let size = typ.size
if size >= 0:
let res = newIntNode(nkIntLit, size)
res.info = node.info
res.typ = node.typ
res
else:
fallback
template foldAlignOf*(conf: ConfigRef; n: PNode; fallback: PNode): PNode =
let config = conf
let node = n
let typ = node[1].typ
computeSizeAlign(config, typ)
let align = typ.align
if align >= 0:
let res = newIntNode(nkIntLit, align)
res.info = node.info
res.typ = node.typ
res
else:
fallback
template foldOffsetOf*(conf: ConfigRef; n: PNode; fallback: PNode): PNode =
## Returns an int literal node of the given offsetof expression in `n`.
## Falls back to `fallback`, if the `offsetof` expression can't be processed.
let config = conf
let node = n
var dotExpr: PNode
block findDotExpr:
if node[1].kind == nkDotExpr:
dotExpr = node[1]
elif node[1].kind == nkCheckedFieldExpr:
dotExpr = node[1][0]
else:
dotExpr = nil
localError(config, node.info, "can't compute offsetof on this ast")
assert dotExpr != nil
let value = dotExpr[0]
let member = dotExpr[1]
computeSizeAlign(config, value.typ)
let offset = member.sym.offset
if offset >= 0:
let tmp = newIntNode(nkIntLit, offset)
tmp.info = node.info
tmp.typ = node.typ
tmp
else:
fallback
|
