diff options
| -rw-r--r-- | compiler/destroyer.nim | 47 | ||||
| -rw-r--r-- | compiler/dfa.nim | 1 | ||||
| -rw-r--r-- | compiler/pragmas.nim | 1 | ||||
| -rw-r--r-- | compiler/semstmts.nim | 2 | ||||
| -rw-r--r-- | tests/destructor/tprevent_assign.nim | 33 |
5 files changed, 65 insertions, 19 deletions
diff --git a/compiler/destroyer.nim b/compiler/destroyer.nim index ff5494ad8..fc8e760bc 100644 --- a/compiler/destroyer.nim +++ b/compiler/destroyer.nim @@ -181,7 +181,7 @@ proc isHarmlessVar*(s: PSym; c: Con): bool = if c.g[i].sym == s: if defsite < 0: defsite = i else: return false - of use: + of use, useWithinCall: if c.g[i].sym == s: if defsite < 0: return false for j in defsite .. i: @@ -190,10 +190,11 @@ proc isHarmlessVar*(s: PSym; c: Con): bool = # if we want to die after the first 'use': if usages > 1: return false inc usages - of useWithinCall: - if c.g[i].sym == s: return false + #of useWithinCall: + # if c.g[i].sym == s: return false of goto, fork: discard "we do not perform an abstract interpretation yet" + result = usages <= 1 template interestingSym(s: PSym): bool = s.owner == c.owner and s.kind in InterestingSyms and hasDestructor(s.typ) @@ -222,26 +223,35 @@ proc patchHead(s: PSym) = if sfFromGeneric in s.flags: patchHead(s.ast[bodyPos]) -template genOp(opr, opname) = +proc checkForErrorPragma(c: Con; t: PType; ri: PNode; opname: string) = + var m = "'" & opname & "' is not available for type <" & typeToString(t) & ">" + if opname == "=" and ri != nil: + m.add "; requires a copy because it's not the last read of '" + m.add renderTree(ri) + m.add '\'' + localError(c.graph.config, ri.info, errGenerated, m) + +template genOp(opr, opname, ri) = let op = opr if op == nil: globalError(c.graph.config, dest.info, "internal error: '" & opname & "' operator not found for type " & typeToString(t)) elif op.ast[genericParamsPos].kind != nkEmpty: globalError(c.graph.config, dest.info, "internal error: '" & opname & "' operator is generic") patchHead op + if sfError in op.flags: checkForErrorPragma(c, t, ri, opname) result = newTree(nkCall, newSymNode(op), newTree(nkHiddenAddr, dest)) -proc genSink(c: Con; t: PType; dest: PNode): PNode = +proc genSink(c: Con; t: PType; dest, ri: PNode): PNode = let t = t.skipTypes({tyGenericInst, tyAlias, tySink}) - genOp(if t.sink != nil: t.sink else: t.assignment, "=sink") + genOp(if t.sink != nil: t.sink else: t.assignment, "=sink", ri) -proc genCopy(c: Con; t: PType; dest: PNode): PNode = +proc genCopy(c: Con; t: PType; dest, ri: PNode): PNode = let t = t.skipTypes({tyGenericInst, tyAlias, tySink}) - genOp(t.assignment, "=") + genOp(t.assignment, "=", ri) proc genDestroy(c: Con; t: PType; dest: PNode): PNode = let t = t.skipTypes({tyGenericInst, tyAlias, tySink}) - genOp(t.destructor, "=destroy") + genOp(t.destructor, "=destroy", nil) proc addTopVar(c: var Con; v: PNode) = c.topLevelVars.add newTree(nkIdentDefs, v, c.emptyNode, c.emptyNode) @@ -291,33 +301,33 @@ proc genMagicCall(n: PNode; c: var Con; magicname: string; m: TMagic): PNode = proc moveOrCopy(dest, ri: PNode; c: var Con): PNode = if ri.kind in constrExprs: - result = genSink(c, dest.typ, dest) + result = genSink(c, dest.typ, dest, ri) # watch out and no not transform 'ri' twice if it's a call: let ri2 = copyNode(ri) recurse(ri, ri2) result.add ri2 - elif ri.kind == nkSym and isHarmlessVar(ri.sym, c): + elif ri.kind == nkSym and ri.sym.kind != skParam and isHarmlessVar(ri.sym, c): # Rule 3: `=sink`(x, z); wasMoved(z) - var snk = genSink(c, dest.typ, dest) + var snk = genSink(c, dest.typ, dest, ri) 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, dest.typ, dest) + result = genSink(c, dest.typ, dest, ri) result.add destructiveMoveSink(ri, c) else: - result = genCopy(c, dest.typ, dest) + result = genCopy(c, dest.typ, dest, ri) result.add p(ri, c) proc passCopyToSink(n: PNode; c: var Con): PNode = result = newNodeIT(nkStmtListExpr, n.info, n.typ) let tmp = getTemp(c, n.typ, n.info) if hasDestructor(n.typ): - var m = genCopy(c, n.typ, tmp) + var m = genCopy(c, n.typ, tmp, n) m.add p(n, c) result.add m message(c.graph.config, n.info, hintPerformance, - "passing '$1' to a sink parameter introduces an implicit copy; " & - "use 'move($1)' to prevent it" % $n) + ("passing '$1' to a sink parameter introduces an implicit copy; " & + "use 'move($1)' to prevent it") % $n) else: result.add newTree(nkAsgn, tmp, p(n, c)) result.add tmp @@ -331,6 +341,7 @@ proc destructiveMoveVar(n: PNode; c: var Con): PNode = result = newNodeIT(nkStmtListExpr, n.info, n.typ) var temp = newSym(skLet, getIdent(c.graph.cache, "blitTmp"), c.owner, n.info) + temp.typ = n.typ var v = newNodeI(nkLetSection, n.info) let tempAsNode = newSymNode(temp) @@ -410,7 +421,7 @@ proc p(n: PNode; c: var Con): PNode = discard "produce temp creation" result = newNodeIT(nkStmtListExpr, n.info, n.typ) let tmp = getTemp(c, n.typ, n.info) - var sinkExpr = genSink(c, n.typ, tmp) + var sinkExpr = genSink(c, n.typ, tmp, n) sinkExpr.add n result.add sinkExpr result.add tmp diff --git a/compiler/dfa.nim b/compiler/dfa.nim index 013242f62..44c89b881 100644 --- a/compiler/dfa.nim +++ b/compiler/dfa.nim @@ -442,4 +442,5 @@ proc dataflowAnalysis*(s: PSym; body: PNode; conf: ConfigRef) = proc constructCfg*(s: PSym; body: PNode): ControlFlowGraph = ## constructs a control flow graph for ``body``. var c = Con(code: @[], blocks: @[]) + gen(c, body) shallowCopy(result, c.code) diff --git a/compiler/pragmas.nim b/compiler/pragmas.nim index 9a624fcce..94790440f 100644 --- a/compiler/pragmas.nim +++ b/compiler/pragmas.nim @@ -961,6 +961,7 @@ proc singlePragma(c: PContext, sym: PSym, n: PNode, i: var int, # ``proc p() {.error}`` and ``proc p() = {.error: "msg".}`` if it.kind in nkPragmaCallKinds: discard getStrLitNode(c, it) incl(sym.flags, sfError) + excl(sym.flags, sfForward) else: let s = expectStrLit(c, it) recordPragma(c, it, "error", s) diff --git a/compiler/semstmts.nim b/compiler/semstmts.nim index d5c5b7f86..f2cb2dcb3 100644 --- a/compiler/semstmts.nim +++ b/compiler/semstmts.nim @@ -1677,7 +1677,7 @@ proc semProcAux(c: PContext, n: PNode, kind: TSymKind, else: if s.kind == skMethod: semMethodPrototype(c, s, n) if proto != nil: localError(c.config, n.info, errImplOfXexpected % proto.name.s) - if {sfImportc, sfBorrow} * s.flags == {} and s.magic == mNone: + if {sfImportc, sfBorrow, sfError} * s.flags == {} and s.magic == mNone: incl(s.flags, sfForward) elif sfBorrow in s.flags: semBorrow(c, n, s) sideEffectsCheck(c, s) diff --git a/tests/destructor/tprevent_assign.nim b/tests/destructor/tprevent_assign.nim new file mode 100644 index 000000000..108ccc371 --- /dev/null +++ b/tests/destructor/tprevent_assign.nim @@ -0,0 +1,33 @@ +discard """ + errormsg: "'=' is not available for type <Foo>; requires a copy because it's not the last read of 'otherTree'" + line: 29 +""" + +type + Foo = object + x: int + +proc `=destroy`(f: var Foo) = f.x = 0 +proc `=`(a: var Foo; b: Foo) {.error.} # = a.x = b.x +proc `=sink`(a: var Foo; b: Foo) = a.x = b.x + +proc createTree(x: int): Foo = + Foo(x: x) + +proc take2(a, b: sink Foo) = + echo a.x, " ", b.x + +proc allowThis() = + # all these temporary lets are harmless: + let otherTree = createTree(44) + let b = otherTree + let c = b + take2(createTree(34), c) + +proc preventThis() = + let otherTree = createTree(44) + let b = otherTree + take2(createTree(34), otherTree) + +allowThis() +preventThis() |