diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/injectdestructors.nim | 118 |
1 files changed, 81 insertions, 37 deletions
diff --git a/compiler/injectdestructors.nim b/compiler/injectdestructors.nim index 56f8026d5..84473aabc 100644 --- a/compiler/injectdestructors.nim +++ b/compiler/injectdestructors.nim @@ -34,7 +34,7 @@ type uninit: IntSet # set of uninit'ed vars uninitComputed: bool -const toDebug {.strdefine.} = "" # "server" # "serverNimAsyncContinue" +const toDebug {.strdefine.} = "" template dbg(body) = when toDebug.len > 0: @@ -47,7 +47,7 @@ proc isLastRead(location: PNode; c: var Con; pc, comesFrom: int): int = case c.g[pc].kind of def: if defInstrTargets(c.g[pc], location): - # the path lead to a redefinition of 's' --> abandon it. + # the path leads to a redefinition of 's' --> abandon it. return high(int) inc pc of use: @@ -85,8 +85,7 @@ proc isLastRead(n: PNode; c: var Con): bool = instr = i break - dbg: - echo "starting point for ", n, " is ", instr, " ", n.kind + dbg: echo "starting point for ", n, " is ", instr, " ", n.kind if instr < 0: return false # we go through all paths beginning from 'instr+1' and need to @@ -94,8 +93,55 @@ proc isLastRead(n: PNode; c: var Con): bool = if instr+1 >= c.g.len: return true result = isLastRead(n, c, instr+1, -1) >= 0 - dbg: - echo "ugh ", c.otherRead.isNil, " ", result + dbg: echo "ugh ", c.otherRead.isNil, " ", result + +proc isFirstWrite(location: PNode; c: var Con; pc, comesFrom: int; instr: int): int = + var pc = pc + while pc < instr: + case c.g[pc].kind + of def: + if defInstrTargets(c.g[pc], location): + # a definition of 's' before ours makes ours not the first write + return -1 + inc pc + of use: + if useInstrTargets(c.g[pc], location): + return -1 + inc pc + of goto: + pc = pc + c.g[pc].dest + of fork: + # every branch must not contain a def/use of our location: + let variantA = isFirstWrite(location, c, pc+1, pc, instr) + if variantA < 0: return -1 + var variantB = isFirstWrite(location, c, pc + c.g[pc].dest, pc, instr + c.g[pc].dest) + if variantB < 0: return -1 + elif variantB == high(int): + variantB = variantA + pc = variantB + of InstrKind.join: + let dest = pc + c.g[pc].dest + if dest == comesFrom: return pc + 1 + inc pc + return pc + +proc isFirstWrite(n: PNode; c: var Con): bool = + # first we need to search for the instruction that belongs to 'n': + var instr = -1 + let m = dfa.skipConvDfa(n) + + for i in countdown(c.g.len-1, 0): # We search backwards here to treat loops correctly + if c.g[i].kind == def and c.g[i].n == m: + if instr < 0: + instr = i + break + + if instr < 0: return false + # we go through all paths going to 'instr' and need to + # ensure that we don't find another 'def/use X' instruction. + if instr == 0: return true + + result = isFirstWrite(n, c, 0, -1, instr) >= 0 proc initialized(code: ControlFlowGraph; pc: int, init, uninit: var IntSet; comesFrom: int): int = @@ -200,22 +246,20 @@ proc canBeMoved(c: Con; t: PType): bool {.inline.} = else: result = t.attachedOps[attachedSink] != nil -proc genSink(c: Con; dest, ri: PNode): PNode = - let t = dest.typ.skipTypes({tyGenericInst, tyAlias, tySink}) - let k = if t.attachedOps[attachedSink] != nil: attachedSink - else: attachedAsgn - if t.attachedOps[k] != nil: - result = genOp(c, t, k, dest, ri) - else: - # in rare cases only =destroy exists but no sink or assignment - # (see Pony object in tmove_objconstr.nim) - # we generate a fast assignment in this case: +proc genSink(c: var Con; dest, ri: PNode): PNode = + if isFirstWrite(dest, c): # optimize sink call into a bitwise memcopy result = newTree(nkFastAsgn, dest) - -proc genSinkOrMemMove(c: Con; dest, ri: PNode, isFirstWrite: bool): PNode = - # optimize sink call into a bitwise memcopy - if isFirstWrite: newTree(nkFastAsgn, dest) - else: genSink(c, dest, ri) + else: + let t = dest.typ.skipTypes({tyGenericInst, tyAlias, tySink}) + let k = if t.attachedOps[attachedSink] != nil: attachedSink + else: attachedAsgn + if t.attachedOps[k] != nil: + result = genOp(c, t, k, dest, ri) + else: + # in rare cases only =destroy exists but no sink or assignment + # (see Pony object in tmove_objconstr.nim) + # we generate a fast assignment in this case: + result = newTree(nkFastAsgn, dest) proc genCopyNoCheck(c: Con; dest, ri: PNode): PNode = let t = dest.typ.skipTypes({tyGenericInst, tyAlias, tySink}) @@ -289,7 +333,7 @@ type sinkArg proc p(n: PNode; c: var Con; mode: ProcessMode): PNode -proc moveOrCopy(dest, ri: PNode; c: var Con, isFirstWrite: bool): PNode +proc moveOrCopy(dest, ri: PNode; c: var Con): PNode proc isClosureEnv(n: PNode): bool = n.kind == nkSym and n.sym.name.s[0] == ':' @@ -552,7 +596,7 @@ proc p(n: PNode; c: var Con; mode: ProcessMode): PNode = if ri.kind == nkEmpty and c.inLoop > 0: ri = genDefaultCall(v.typ, c, v.info) if ri.kind != nkEmpty: - let r = moveOrCopy(v, ri, c, isFirstWrite = (c.inLoop == 0)) + let r = moveOrCopy(v, ri, c) result.add r else: # keep the var but transform 'ri': var v = copyNode(n) @@ -572,7 +616,7 @@ proc p(n: PNode; c: var Con; mode: ProcessMode): PNode = if n[0].kind in {nkDotExpr, nkCheckedFieldExpr}: cycleCheck(n, c) assert n[1].kind notin {nkAsgn, nkFastAsgn} - result = moveOrCopy(n[0], n[1], c, isFirstWrite = false) + result = moveOrCopy(n[0], n[1], c) else: result = copyNode(n) result.add copyTree(n[0]) @@ -615,13 +659,13 @@ proc p(n: PNode; c: var Con; mode: ProcessMode): PNode = for i in 0..<n.len: result[i] = p(n[i], c, mode) -proc moveOrCopy(dest, ri: PNode; c: var Con, isFirstWrite: bool): PNode = +proc moveOrCopy(dest, ri: PNode; c: var Con): PNode = case ri.kind of nkCallKinds: if isUnpackedTuple(dest): result = newTree(nkFastAsgn, dest, p(ri, c, consumed)) else: - result = genSinkOrMemMove(c, dest, ri, isFirstWrite) + result = genSink(c, dest, ri) result.add p(ri, c, consumed) of nkBracketExpr: if isUnpackedTuple(ri[0]): @@ -629,7 +673,7 @@ proc moveOrCopy(dest, ri: PNode; c: var Con, isFirstWrite: bool): PNode = result = newTree(nkFastAsgn, dest, p(ri, c, consumed)) elif isAnalysableFieldAccess(ri, c.owner) and isLastRead(ri, c): # Rule 3: `=sink`(x, z); wasMoved(z) - var snk = genSinkOrMemMove(c, dest, ri, isFirstWrite) + var snk = genSink(c, dest, ri) snk.add ri result = newTree(nkStmtList, snk, genWasMoved(ri, c)) else: @@ -640,22 +684,22 @@ proc moveOrCopy(dest, ri: PNode; c: var Con, isFirstWrite: bool): PNode = if ri.len > 0 and isDangerousSeq(ri.typ): result = genCopy(c, dest, ri) else: - result = genSinkOrMemMove(c, dest, ri, isFirstWrite) + result = genSink(c, dest, ri) result.add p(ri, c, consumed) of nkObjConstr, nkTupleConstr, nkClosure, nkCharLit..nkNilLit: - result = genSinkOrMemMove(c, dest, ri, isFirstWrite) + result = genSink(c, dest, ri) result.add p(ri, c, consumed) of nkSym: if isSinkParam(ri.sym): # Rule 3: `=sink`(x, z); wasMoved(z) sinkParamIsLastReadCheck(c, ri) - var snk = genSinkOrMemMove(c, dest, ri, isFirstWrite) + var snk = genSink(c, dest, ri) snk.add ri result = newTree(nkStmtList, snk, genWasMoved(ri, c)) elif ri.sym.kind != skParam and ri.sym.owner == c.owner and isLastRead(ri, c) and canBeMoved(c, dest.typ): # Rule 3: `=sink`(x, z); wasMoved(z) - var snk = genSinkOrMemMove(c, dest, ri, isFirstWrite) + var snk = genSink(c, dest, ri) snk.add ri result = newTree(nkStmtList, snk, genWasMoved(ri, c)) else: @@ -663,30 +707,30 @@ proc moveOrCopy(dest, ri: PNode; c: var Con, isFirstWrite: bool): PNode = result.add p(ri, c, consumed) of nkHiddenSubConv, nkHiddenStdConv, nkConv: when false: - result = moveOrCopy(dest, ri[1], c, isFirstWrite) + result = moveOrCopy(dest, ri[1], c) if not sameType(ri.typ, ri[1].typ): let copyRi = copyTree(ri) copyRi[1] = result[^1] result[^1] = copyRi else: - result = genSinkOrMemMove(c, dest, ri, isFirstWrite) + result = genSink(c, dest, ri) result.add p(ri, c, sinkArg) of nkObjDownConv, nkObjUpConv: when false: - result = moveOrCopy(dest, ri[0], c, isFirstWrite) + result = moveOrCopy(dest, ri[0], c) let copyRi = copyTree(ri) copyRi[0] = result[^1] result[^1] = copyRi else: - result = genSinkOrMemMove(c, dest, ri, isFirstWrite) + result = genSink(c, dest, ri) result.add p(ri, c, sinkArg) of nkStmtListExpr, nkBlockExpr, nkIfExpr, nkCaseStmt: - handleNested(ri): moveOrCopy(dest, node, c, isFirstWrite) + handleNested(ri): moveOrCopy(dest, node, c) else: if isAnalysableFieldAccess(ri, c.owner) and isLastRead(ri, c) and canBeMoved(c, dest.typ): # Rule 3: `=sink`(x, z); wasMoved(z) - var snk = genSinkOrMemMove(c, dest, ri, isFirstWrite) + var snk = genSink(c, dest, ri) snk.add ri result = newTree(nkStmtList, snk, genWasMoved(ri, c)) else: |