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sizealign of union type (#10780)

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* sizealign of union type

* add error message for packed union
This commit is contained in:
Arne Döring 2019-03-04 09:19:38 +01:00 • committed by Andreas Rumpf
commit 1d9b88f25d
2 changed files with 62 additions and 4 deletions
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54
compiler/sizealignoffsetimpl.nim
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@ -145,6 +145,9 @@ proc computePackedObjectOffsetsFoldFunction(conf: ConfigRef; n: PNode, initialOf
var maxChildOffset: BiggestInt = kindUnionOffset
for i in 1 ..< sonsLen(n):
let offset = computePackedObjectOffsetsFoldFunction(conf, n.sons[i].lastSon, kindUnionOffset, debug)
if offset < 0:
result = offset
break
maxChildOffset = max(maxChildOffset, offset)
result = maxChildOffset
of nkRecList:
@ -168,7 +171,47 @@ proc computePackedObjectOffsetsFoldFunction(conf: ConfigRef; n: PNode, initialOf
else:
result = szUnknownSize
# TODO this one needs an alignment map of the individual types
proc computeUnionObjectOffsetsFoldFunction(conf: ConfigRef; n: PNode, debug: bool): tuple[offset, align: BiggestInt] =
## ``result`` is the offset from the larget member of the union.
case n.kind
of nkRecCase:
result.offset = szUnknownSize
result.align = szUnknownSize
localError(conf, n.info, "Illegal use of ``case`` in union type.")
#internalError(conf, "Illegal use of ``case`` in union type.")
of nkRecList:
var maxChildOffset: BiggestInt = 0
for i, child in n.sons:
let (offset, align) = computeUnionObjectOffsetsFoldFunction(conf, child, debug)
if offset == szIllegalRecursion or align == szIllegalRecursion:
result.offset = szIllegalRecursion
result.align = szIllegalRecursion
elif offset == szUnknownSize or align == szUnknownSize:
result.offset = szUnknownSize
result.align = szUnknownSize
else:
assert offset != szUncomputedSize
assert align != szUncomputedSize
result.offset = max(result.offset, offset)
result.align = max(result.align, align)
of nkSym:
var size = szUnknownSize
var align = szUnknownSize
if n.sym.bitsize == 0: # 0 represents bitsize not set
computeSizeAlign(conf, n.sym.typ)
size = n.sym.typ.size.int
align = n.sym.typ.align.int
result.align = align
if size == szUnknownSize:
n.sym.offset = szUnknownSize
result.offset = szUnknownSize
else:
n.sym.offset = 0
result.offset = n.sym.typ.size
else:
result.offset = szUnknownSize
result.align = szUnknownSize
proc computeSizeAlign(conf: ConfigRef; typ: PType) =
## computes and sets ``size`` and ``align`` members of ``typ``
@ -343,7 +386,14 @@ proc computeSizeAlign(conf: ConfigRef; typ: PType) =
headerSize = 0
headerAlign = 1
let (offset, align) =
if tfPacked in typ.flags:
if tfUnion in typ.flags:
if tfPacked in typ.flags:
let info = if typ.sym != nil: typ.sym.info else: unknownLineInfo()
localError(conf, info, "type may not be packed and union at the same time.")
(BiggestInt(szUnknownSize), BiggestInt(szUnknownSize))
else:
computeUnionObjectOffsetsFoldFunction(conf, typ.n, false)
elif tfPacked in typ.flags:
(computePackedObjectOffsetsFoldFunction(conf, typ.n, headerSize, false), BiggestInt(1))
else:
computeObjectOffsetsFoldFunction(conf, typ.n, headerSize)