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WIP: strings/seqs based on destructors

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This commit is contained in:
Andreas Rumpf 2018-07-17 13:19:42 +02:00
commit 32afdc09c6
13 changed files with 240 additions and 141 deletions
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25
compiler/destroyer.nim
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@ -100,12 +100,12 @@ Rule Pattern Transformed into
finally: `=destroy`(x)
1.2 var x: sink T; stmts var x: sink T; stmts; ensureEmpty(x)
2 x = f() `=sink`(x, f())
3 x = lastReadOf z `=sink`(x, z)
3 x = lastReadOf z `=sink`(x, z); wasMoved(z)
4.1 y = sinkParam `=sink`(y, sinkParam)
4.2 x = y `=`(x, y) # a copy
5.1 f_sink(g()) f_sink(g())
5.2 f_sink(y) f_sink(copy y); # copy unless we can see it's the last read
5.3 f_sink(move y) f_sink(y); reset(y) # explicit moves empties 'y'
5.3 f_sink(move y) f_sink(y); wasMoved(y) # explicit moves empties 'y'
5.4 f_noSink(g()) var tmp = bitwiseCopy(g()); f(tmp); `=destroy`(tmp)
Remarks: Rule 1.2 is not yet implemented because ``sink`` is currently
@ -282,6 +282,11 @@ proc destructiveMoveSink(n: PNode; c: var Con): PNode =
newIntTypeNode(nkIntLit, 0, getSysType(c.graph, n.info, tyBool)))
result.add n
proc genMagicCall(n: PNode; c: var Con; magicname: string; m: TMagic): PNode =
result = newNodeI(nkCall, n.info)
result.add(newSymNode(createMagic(c.graph, magicname, m)))
result.add n
proc moveOrCopy(dest, ri: PNode; c: var Con): PNode =
if ri.kind in constrExprs:
result = genSink(c, ri.typ, dest)
@ -290,8 +295,10 @@ proc moveOrCopy(dest, ri: PNode; c: var Con): PNode =
recurse(ri, ri2)
result.add ri2
elif ri.kind == nkSym and isHarmlessVar(ri.sym, c):
result = genSink(c, ri.typ, dest)
result.add p(ri, c)
# Rule 3: `=sink`(x, z); wasMoved(z)
var snk = genSink(c, ri.typ, dest)
snk.add p(ri, c)
result = newTree(nkStmtList, snk, genMagicCall(ri, c, "wasMoved", mWasMoved))
elif ri.kind == nkSym and isSinkParam(ri.sym):
result = genSink(c, ri.typ, dest)
result.add destructiveMoveSink(ri, c)
@ -313,11 +320,9 @@ proc passCopyToSink(n: PNode; c: var Con): PNode =
result.add newTree(nkAsgn, tmp, p(n, c))
result.add tmp
proc genReset(n: PNode; c: var Con): PNode =
result = newNodeI(nkCall, n.info)
result.add(newSymNode(createMagic(c.graph, "reset", mReset)))
# The mReset builtin does not take the address:
result.add n
proc genWasMoved(n: PNode; c: var Con): PNode =
# The mWasMoved builtin does not take the address.
result = genMagicCall(n, c, "wasMoved", mWasMoved)
proc destructiveMoveVar(n: PNode; c: var Con): PNode =
# generate: (let tmp = v; reset(v); tmp)
@ -334,7 +339,7 @@ proc destructiveMoveVar(n: PNode; c: var Con): PNode =
add(v, vpart)
result.add v
result.add genReset(n, c)
result.add genWasMoved(n, c)
result.add tempAsNode
proc p(n: PNode; c: var Con): PNode =