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#
#
# The Nim Compiler
# (c) Copyright 2014 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## This module implements lifting for assignments and ``deepCopy``.
# included from sem.nim
type
TLiftCtx = object
c: PContext
info: TLineInfo # for construction
result: PNode
kind: TTypeAttachedOp
type
TFieldInstCtx = object # either 'tup[i]' or 'field' is valid
tupleType: PType # if != nil we're traversing a tuple
tupleIndex: int
field: PSym
replaceByFieldName: bool
proc instFieldLoopBody(c: TFieldInstCtx, n: PNode, forLoop: PNode): PNode =
case n.kind
of nkEmpty..pred(nkIdent), succ(nkIdent)..nkNilLit: result = n
of nkIdent:
result = n
var L = sonsLen(forLoop)
if c.replaceByFieldName:
if n.ident.id == forLoop[0].ident.id:
let fieldName = if c.tupleType.isNil: c.field.name.s
elif c.tupleType.n.isNil: "Field" & $c.tupleIndex
else: c.tupleType.n.sons[c.tupleIndex].sym.name.s
result = newStrNode(nkStrLit, fieldName)
return
# other fields:
for i in ord(c.replaceByFieldName)..L-3:
if n.ident.id == forLoop[i].ident.id:
var call = forLoop.sons[L-2]
var tupl = call.sons[i+1-ord(c.replaceByFieldName)]
if c.field.isNil:
result = newNodeI(nkBracketExpr, n.info)
result.add(tupl)
result.add(newIntNode(nkIntLit, c.tupleIndex))
else:
result = newNodeI(nkDotExpr, n.info)
result.add(tupl)
result.add(newSymNode(c.field, n.info))
break
else:
if n.kind == nkContinueStmt:
localError(n.info, errGenerated,
"'continue' not supported in a 'fields' loop")
result = copyNode(n)
newSons(result, sonsLen(n))
for i in countup(0, sonsLen(n)-1):
result.sons[i] = instFieldLoopBody(c, n.sons[i], forLoop)
proc liftBodyObj(c: TLiftCtx; typ, x, y: PNode) =
case typ.kind
of nkSym:
var fc: TFieldInstCtx # either 'tup[i]' or 'field' is valid
fc.field = typ.sym
fc.replaceByFieldName = c.m == mFieldPairs
openScope(c.c)
inc c.c.inUnrolledContext
let body = instFieldLoopBody(fc, lastSon(forLoop), forLoop)
father.add(semStmt(c.c, body))
dec c.c.inUnrolledContext
closeScope(c.c)
of nkNilLit: discard
of nkRecCase:
let L = forLoop.len
let call = forLoop.sons[L-2]
if call.len > 2:
localError(forLoop.info, errGenerated,
"parallel 'fields' iterator does not work for 'case' objects")
return
# iterate over the selector:
asgnForObjectFields(c, typ[0], forLoop, father)
# we need to generate a case statement:
var caseStmt = newNodeI(nkCaseStmt, c.info)
# generate selector:
var access = newNodeI(nkDotExpr, forLoop.info, 2)
access.sons[0] = call.sons[1]
access.sons[1] = newSymNode(typ.sons[0].sym, forLoop.info)
caseStmt.add(semExprWithType(c.c, access))
# copy the branches over, but replace the fields with the for loop body:
for i in 1 .. <typ.len:
var branch = copyTree(typ[i])
let L = branch.len
branch.sons[L-1] = newNodeI(nkStmtList, forLoop.info)
semForObjectFields(c, typ[i].lastSon, forLoop, branch[L-1])
caseStmt.add(branch)
father.add(caseStmt)
of nkRecList:
for t in items(typ): liftBodyObj(c, t, x, y)
else:
illFormedAst(typ)
proc newAsgnCall(op: PSym; x, y: PNode): PNode =
result = newNodeI(nkCall, x.info)
result.add(newSymNode(op))
result.add x
result.add y
proc newAsgnStmt(le, ri: PNode): PNode =
result = newNodeI(nkAsgn, le.info, 2)
result.sons[0] = le
result.sons[1] = ri
proc newDestructorCall(op: PSym; x: PNode): PNode =
result = newNodeIT(nkCall, x.info, op.typ.sons[0])
result.add(newSymNode(op))
result.add x
proc newDeepCopyCall(op: PSym; x, y: PNode): PNode =
result = newAsgnStmt(x, newDestructorCall(op, y))
proc considerOverloadedOp(c: TLiftCtx; t: PType; x, y: PNode): bool =
let op = t.attachedOps[c.kind]
if op != nil:
markUsed(c.info, op)
styleCheckUse(c.info, op)
case c.kind
of attachedDestructor:
c.result.add newDestructorCall(op, x)
of attachedAsgn:
c.result.add newAsgnCall(op, x, y)
of attachedDeepCopy:
c.result.add newDeepCopyCall(op, x, y)
result = true
proc defaultOp(c: TLiftCtx; t: PType; x, y: PNode) =
if c.kind != attachedDestructor:
c.result.add newAsgnStmt(x, y)
proc liftBodyAux(c: TLiftCtx; t: PType; x, y: PNode) =
const hasAttachedOp: array[TTypeAttachedOp, TTypeIter] = [
(proc (t: PType, closure: PObject): bool =
t.attachedOp[attachedDestructor] != nil),
(proc (t: PType, closure: PObject): bool =
t.attachedOp[attachedAsgn] != nil),
(proc (t: PType, closure: PObject): bool =
t.attachedOp[attachedDeepCopy] != nil)]
case t.kind
of tyNone, tyEmpty: discard
of tyPointer, tySet, tyBool, tyChar, tyEnum, tyInt..tyUInt64, tyCString:
defaultOp(c, t, x, y)
of tyPtr, tyString:
if not considerOverloadedOp(c, t, x, y):
defaultOp(c, t, x, y)
of tyArrayConstr, tyArray, tySequence:
if iterOverType(lastSon(t), hasAttachedOp[c.kind], nil):
# generate loop and call the attached Op:
else:
defaultOp(c, t, x, y)
of tyObject:
liftBodyObj(c, t.n, x, y)
of tyTuple:
liftBodyTup(c, t, x, y)
of tyRef:
# we MUST not check for acyclic here as a DAG might still share nodes:
of tyProc:
if t.callConv != ccClosure or c.kind != attachedDeepCopy:
defaultOp(c, t, x, y)
else:
# a big problem is that we don't know the enviroment's type here, so we
# have to go through some indirection; we delegate this to the codegen:
call = newNodeI(nkCall, n.info, 2)
call.typ = t
call.sons[0] = newSymNode(createMagic("deepCopy", mDeepCopy))
call.sons[1] = y
c.result.add newAsgnStmt(x, call)
of tyVarargs, tyOpenArray:
localError(c.info, errGenerated, "cannot copy openArray")
of tyFromExpr, tyIter, tyProxy, tyBuiltInTypeClass, tyUserTypeClass,
tyUserTypeClassInst, tyCompositeTypeClass, tyAnd, tyOr, tyNot, tyAnything,
tyMutable, tyGenericParam, tyGenericBody, tyNil, tyExpr, tyStmt,
tyTypeDesc, tyGenericInvokation, tyBigNum, tyConst, tyForward:
internalError(c.info, "assignment requested for type: " & typeToString(t))
of tyDistinct, tyOrdinal, tyRange,
tyGenericInst, tyFieldAccessor, tyStatic, tyVar:
liftBodyAux(c, lastSon(t))
proc liftBody(c: PContext; typ: PType; info: TLineInfo): PNode =
var a: TLiftCtx
a.info = info
a.result = newNodeI(nkStmtList, info)
liftBodyAux(a, typ)
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