jyapayne/Nim
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

arc: cursors for simple for loop variables (#15008)

Browse source 
* arc: cursors for simple for loop variables

* merged devel
This commit is contained in:
Andreas Rumpf 2020-07-17 15:24:36 +02:00 • committed by GitHub
commit d4984e069a
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
4 changed files with 52 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

24
compiler/transf.nim
View file

@ -350,7 +350,7 @@ proc transformYield(c: PTransf, n: PNode): PNode =
# Choose the right assignment instruction according to the given ``lhs``
# node since it may not be a nkSym (a stack-allocated skForVar) but a
# nkDotExpr (a heap-allocated slot into the envP block)
case lhs.kind:
case lhs.kind
of nkSym:
internalAssert c.graph.config, lhs.sym.kind == skForVar
result = newAsgnStmt(c, nkFastAsgn, lhs, rhs)
@ -592,6 +592,22 @@ proc findWrongOwners(c: PTransf, n: PNode) =
else:
for i in 0..<n.safeLen: findWrongOwners(c, n[i])
proc isSimpleIteratorVar(iter: PSym): bool =
proc rec(n: PNode; owner: PSym; dangerousYields: var int) =
case n.kind
of nkEmpty..nkNilLit: discard
of nkYieldStmt:
if n[0].kind == nkSym and n[0].sym.owner == owner:
discard "good: yield a single variable that we own"
else:
inc dangerousYields
else:
for c in n: rec(c, owner, dangerousYields)
var dangerousYields = 0
rec(iter.ast[bodyPos], iter, dangerousYields)
result = dangerousYields == 0
proc transformFor(c: PTransf, n: PNode): PNode =
# generate access statements for the parameters (unless they are constant)
# put mapping from formal parameters to actual parameters
@ -624,18 +640,22 @@ proc transformFor(c: PTransf, n: PNode): PNode =
discard c.breakSyms.pop
let iter = call[0].sym
var v = newNodeI(nkVarSection, n.info)
for i in 0..<n.len - 2:
if n[i].kind == nkVarTuple:
for j in 0..<n[i].len-1:
addVar(v, copyTree(n[i][j])) # declare new vars
else:
if n[i].kind == nkSym and isSimpleIteratorVar(iter):
incl n[i].sym.flags, sfCursor
addVar(v, copyTree(n[i])) # declare new vars
stmtList.add(v)
# Bugfix: inlined locals belong to the invoking routine, not to the invoked
# iterator!
let iter = call[0].sym
var newC = newTransCon(getCurrOwner(c))
newC.forStmt = n
newC.forLoopBody = loopBody