diff options
Diffstat (limited to 'compiler/sempass2.nim')
| -rw-r--r-- | compiler/sempass2.nim | 87 |
1 files changed, 68 insertions, 19 deletions
diff --git a/compiler/sempass2.nim b/compiler/sempass2.nim index 0954f42fd..823699a8c 100644 --- a/compiler/sempass2.nim +++ b/compiler/sempass2.nim @@ -352,20 +352,25 @@ proc useVar(a: PEffects, n: PNode) = a.init.add s.id useVarNoInitCheck(a, n, s) +type + BreakState = enum + bsNone + bsBreakOrReturn + bsNoReturn type TIntersection = seq[tuple[id, count: int]] # a simple count table -proc addToIntersection(inter: var TIntersection, s: int, initOnly: bool) = +proc addToIntersection(inter: var TIntersection, s: int, state: BreakState) = for j in 0..<inter.len: if s == inter[j].id: - if not initOnly: + if state == bsNone: inc inter[j].count return - if initOnly: - inter.add((id: s, count: 0)) - else: + if state == bsNone: inter.add((id: s, count: 1)) + else: + inter.add((id: s, count: 0)) proc throws(tracked, n, orig: PNode) = if n.typ == nil or n.typ.kind != tyError: @@ -469,7 +474,7 @@ proc trackTryStmt(tracked: PEffects, n: PNode) = track(tracked, n[0]) dec tracked.inTryStmt for i in oldState..<tracked.init.len: - addToIntersection(inter, tracked.init[i], false) + addToIntersection(inter, tracked.init[i], bsNone) var branches = 1 var hasFinally = false @@ -504,7 +509,7 @@ proc trackTryStmt(tracked: PEffects, n: PNode) = tracked.init.add b[j][2].sym.id track(tracked, b[^1]) for i in oldState..<tracked.init.len: - addToIntersection(inter, tracked.init[i], false) + addToIntersection(inter, tracked.init[i], bsNone) else: setLen(tracked.init, oldState) track(tracked, b[^1]) @@ -673,15 +678,50 @@ proc trackOperandForIndirectCall(tracked: PEffects, n: PNode, formals: PType; ar localError(tracked.config, n.info, $n & " is not GC safe") notNilCheck(tracked, n, paramType) -proc breaksBlock(n: PNode): bool = + +proc breaksBlock(n: PNode): BreakState = # semantic check doesn't allow statements after raise, break, return or # call to noreturn proc, so it is safe to check just the last statements var it = n while it.kind in {nkStmtList, nkStmtListExpr} and it.len > 0: it = it.lastSon - result = it.kind in {nkBreakStmt, nkReturnStmt, nkRaiseStmt} or - it.kind in nkCallKinds and it[0].kind == nkSym and sfNoReturn in it[0].sym.flags + case it.kind + of nkBreakStmt, nkReturnStmt: + result = bsBreakOrReturn + of nkRaiseStmt: + result = bsNoReturn + of nkCallKinds: + if it[0].kind == nkSym and sfNoReturn in it[0].sym.flags: + result = bsNoReturn + else: + result = bsNone + else: + result = bsNone + +proc addIdToIntersection(tracked: PEffects, inter: var TIntersection, resCounter: var int, + hasBreaksBlock: BreakState, oldState: int, resSym: PSym, hasResult: bool) = + if hasResult: + var alreadySatisfy = false + + if hasBreaksBlock == bsNoReturn: + alreadySatisfy = true + inc resCounter + + for i in oldState..<tracked.init.len: + if tracked.init[i] == resSym.id: + if not alreadySatisfy: + inc resCounter + alreadySatisfy = true + else: + addToIntersection(inter, tracked.init[i], hasBreaksBlock) + else: + for i in oldState..<tracked.init.len: + addToIntersection(inter, tracked.init[i], hasBreaksBlock) + +template hasResultSym(s: PSym): bool = + s != nil and s.kind in {skProc, skFunc, skConverter, skMethod} and + not isEmptyType(s.typ[0]) proc trackCase(tracked: PEffects, n: PNode) = track(tracked, n[0]) @@ -694,6 +734,10 @@ proc trackCase(tracked: PEffects, n: PNode) = (tracked.config.hasWarn(warnProveField) or strictCaseObjects in tracked.c.features) var inter: TIntersection = @[] var toCover = 0 + let hasResult = hasResultSym(tracked.owner) + let resSym = if hasResult: tracked.owner.ast[resultPos].sym else: nil + var resCounter = 0 + for i in 1..<n.len: let branch = n[i] setLen(tracked.init, oldState) @@ -703,13 +747,14 @@ proc trackCase(tracked: PEffects, n: PNode) = for i in 0..<branch.len: track(tracked, branch[i]) let hasBreaksBlock = breaksBlock(branch.lastSon) - if not hasBreaksBlock: + if hasBreaksBlock == bsNone: inc toCover - for i in oldState..<tracked.init.len: - addToIntersection(inter, tracked.init[i], hasBreaksBlock) + addIdToIntersection(tracked, inter, resCounter, hasBreaksBlock, oldState, resSym, hasResult) setLen(tracked.init, oldState) if not stringCase or lastSon(n).kind == nkElse: + if hasResult and resCounter == n.len-1: + tracked.init.add resSym.id for id, count in items(inter): if count >= toCover: tracked.init.add id # else we can't merge @@ -723,14 +768,17 @@ proc trackIf(tracked: PEffects, n: PNode) = addFact(tracked.guards, n[0][0]) let oldState = tracked.init.len + let hasResult = hasResultSym(tracked.owner) + let resSym = if hasResult: tracked.owner.ast[resultPos].sym else: nil + var resCounter = 0 + var inter: TIntersection = @[] var toCover = 0 track(tracked, n[0][1]) let hasBreaksBlock = breaksBlock(n[0][1]) - if not hasBreaksBlock: + if hasBreaksBlock == bsNone: inc toCover - for i in oldState..<tracked.init.len: - addToIntersection(inter, tracked.init[i], hasBreaksBlock) + addIdToIntersection(tracked, inter, resCounter, hasBreaksBlock, oldState, resSym, hasResult) for i in 1..<n.len: let branch = n[i] @@ -743,13 +791,14 @@ proc trackIf(tracked: PEffects, n: PNode) = for i in 0..<branch.len: track(tracked, branch[i]) let hasBreaksBlock = breaksBlock(branch.lastSon) - if not hasBreaksBlock: + if hasBreaksBlock == bsNone: inc toCover - for i in oldState..<tracked.init.len: - addToIntersection(inter, tracked.init[i], hasBreaksBlock) + addIdToIntersection(tracked, inter, resCounter, hasBreaksBlock, oldState, resSym, hasResult) setLen(tracked.init, oldState) if lastSon(n).len == 1: + if hasResult and resCounter == n.len: + tracked.init.add resSym.id for id, count in items(inter): if count >= toCover: tracked.init.add id # else we can't merge as it is not exhaustive |