diff options
Diffstat (limited to 'compiler/sempass2.nim')
| -rw-r--r-- | compiler/sempass2.nim | 112 |
1 files changed, 97 insertions, 15 deletions
diff --git a/compiler/sempass2.nim b/compiler/sempass2.nim index a00325277..b2b91490c 100644 --- a/compiler/sempass2.nim +++ b/compiler/sempass2.nim @@ -59,15 +59,19 @@ discard """ --> we need a stack of scopes for this analysis """ +const trackGlobals = false ## we don't need it for now + type TEffects = object exc: PNode # stack of exceptions tags: PNode # list of tags + uses: PNode # list of used global variables bottom: int owner: PSym init: seq[int] # list of initialized variables guards: TModel # nested guards locked: seq[PNode] # locked locations + gcUnsafe: bool PEffects = var TEffects proc isLocalVar(a: PEffects, s: PSym): bool = @@ -89,20 +93,29 @@ proc initVarViaNew(a: PEffects, n: PNode) = # are initialized: initVar(a, n) +when trackGlobals: + proc addUse(a: PEffects, e: PNode) = + var aa = a.uses + for i in 0 .. <aa.len: + if aa[i].sym.id == e.sym.id: return + a.uses.add(e) + proc useVar(a: PEffects, n: PNode) = let s = n.sym if isLocalVar(a, s): if s.id notin a.init: if {tfNeedsInit, tfNotNil} * s.typ.flags != {}: - when true: - message(n.info, warnProveInit, s.name.s) - else: - Message(n.info, errGenerated, - "'$1' might not have been initialized" % s.name.s) + message(n.info, warnProveInit, s.name.s) else: message(n.info, warnUninit, s.name.s) # prevent superfluous warnings about the same variable: a.init.add s.id + if {sfGlobal, sfThread} * s.flags == {sfGlobal} and s.kind == skVar: + when trackGlobals: + a.addUse(copyNode(n)) + if tfHasGCedMem in s.typ.flags: + message(n.info, warnGcUnsafe, renderTree(n)) + a.gcUnsafe = true type TIntersection = seq[tuple[id, count: int]] # a simple count table @@ -132,6 +145,10 @@ proc createTag(n: PNode): PNode = result.typ = sysTypeFromName"TEffect" if not n.isNil: result.info = n.info +proc createAnyGlobal(n: PNode): PNode = + result = newSymNode(anyGlobal) + result.info = n.info + proc addEffect(a: PEffects, e: PNode, useLineInfo=true) = assert e.kind != nkRaiseStmt var aa = a.exc @@ -161,9 +178,17 @@ proc mergeTags(a: PEffects, b, comesFrom: PNode) = else: for effect in items(b): addTag(a, effect, useLineInfo=comesFrom != nil) +when trackGlobals: + proc mergeUses(a: PEffects, b, comesFrom: PNode) = + if b.isNil: + addUse(a, createAnyGlobal(comesFrom)) + else: + for effect in items(b): addUse(a, effect) + proc listEffects(a: PEffects) = for e in items(a.exc): message(e.info, hintUser, typeToString(e.typ)) for e in items(a.tags): message(e.info, hintUser, typeToString(e.typ)) + for e in items(a.uses): message(e.info, hintUser, e.sym.name.s) proc catches(tracked: PEffects, e: PType) = let e = skipTypes(e, skipPtrs) @@ -289,6 +314,13 @@ proc documentRaises*(n: PNode) = if n.sons[namePos].kind != nkSym: return documentEffect(n, n.sons[pragmasPos], wRaises, exceptionEffects) documentEffect(n, n.sons[pragmasPos], wTags, tagEffects) + documentEffect(n, n.sons[pragmasPos], wUses, usesEffects) + +template notGcSafe(t): expr = {tfGcSafe, tfNoSideEffect} * t.flags == {} + +proc importedFromC(n: PNode): bool = + # when imported from C, we assume GC-safety. + result = n.kind == nkSym and sfImportc in n.sym.flags proc propagateEffects(tracked: PEffects, n: PNode, s: PSym) = let pragma = s.ast.sons[pragmasPos] @@ -298,6 +330,14 @@ proc propagateEffects(tracked: PEffects, n: PNode, s: PSym) = let tagSpec = effectSpec(pragma, wTags) mergeTags(tracked, tagSpec, n) + if notGcSafe(s.typ) and sfImportc notin s.flags: + message(n.info, warnGcUnsafe, renderTree(n)) + tracked.gcUnsafe = true + + when trackGlobals: + let usesSpec = effectSpec(pragma, wUses) + mergeUses(tracked, usesSpec, n) + proc notNilCheck(tracked: PEffects, n: PNode, paramType: PType) = let n = n.skipConv if paramType != nil and tfNotNil in paramType.flags and @@ -330,9 +370,18 @@ proc trackOperand(tracked: PEffects, n: PNode, paramType: PType) = else: addEffect(tracked, createRaise(n)) addTag(tracked, createTag(n)) + when trackGlobals: addUse(tracked, createAnyGlobal(n)) + # assume GcUnsafe unless in its type: + if notGcSafe(op): + message(n.info, warnGcUnsafe, renderTree(n)) + tracked.gcUnsafe = true else: mergeEffects(tracked, effectList.sons[exceptionEffects], n) mergeTags(tracked, effectList.sons[tagEffects], n) + when trackGlobals: mergeUses(tracked, effectList.sons[usesEffects], n) + if notGcSafe(op): + message(n.info, warnGcUnsafe, renderTree(n)) + tracked.gcUnsafe = true notNilCheck(tracked, n, paramType) proc breaksBlock(n: PNode): bool = @@ -451,8 +500,11 @@ proc track(tracked: PEffects, n: PNode) = # XXX: in rare situations, templates and macros will reach here after # calling getAst(templateOrMacro()). Currently, templates and macros # are indistinguishable from normal procs (both have tyProc type) and - # we can detect them only by cheking for attached nkEffectList. + # we can detect them only by checking for attached nkEffectList. if op != nil and op.kind == tyProc and op.n.sons[0].kind == nkEffectList: + if notGcSafe(op) and not importedFromC(a): + message(n.info, warnGcUnsafe, renderTree(n)) + tracked.gcUnsafe = true var effectList = op.n.sons[0] if a.kind == nkSym and a.sym.kind == skMethod: propagateEffects(tracked, n, a.sym) @@ -462,9 +514,11 @@ proc track(tracked: PEffects, n: PNode) = elif isIndirectCall(a, tracked.owner): addEffect(tracked, createRaise(n)) addTag(tracked, createTag(n)) + when trackGlobals: addUse(tracked, createAnyGlobal(n)) else: mergeEffects(tracked, effectList.sons[exceptionEffects], n) mergeTags(tracked, effectList.sons[tagEffects], n) + when trackGlobals: mergeUses(tracked, effectList.sons[usesEffects], n) for i in 1 .. <len(n): trackOperand(tracked, n.sons[i], paramType(op, i)) if a.kind == nkSym and a.sym.magic in {mNew, mNewFinalize, mNewSeq}: # may not look like an assignment, but it is: @@ -531,14 +585,21 @@ proc track(tracked: PEffects, n: PNode) = else: for i in 0 .. <safeLen(n): track(tracked, n.sons[i]) -proc checkRaisesSpec(spec, real: PNode, msg: string, hints: bool) = +proc subtypeRelation(spec, real: PNode): bool = + result = safeInheritanceDiff(real.excType, spec.typ) <= 0 + +proc symbolPredicate(spec, real: PNode): bool = + result = real.sym.id == spec.sym.id + +proc checkRaisesSpec(spec, real: PNode, msg: string, hints: bool; + effectPredicate: proc (a, b: PNode): bool {.nimcall.}) = # check that any real exception is listed in 'spec'; mark those as used; # report any unused exception var used = initIntSet() for r in items(real): block search: for s in 0 .. <spec.len: - if safeInheritanceDiff(r.excType, spec[s].typ) <= 0: + if effectPredicate(spec[s], r): used.incl(s) break search # XXX call graph analysis would be nice here! @@ -560,11 +621,18 @@ proc checkMethodEffects*(disp, branch: PSym) = let raisesSpec = effectSpec(p, wRaises) if not isNil(raisesSpec): checkRaisesSpec(raisesSpec, actual.sons[exceptionEffects], - "can raise an unlisted exception: ", hints=off) + "can raise an unlisted exception: ", hints=off, subtypeRelation) let tagsSpec = effectSpec(p, wTags) if not isNil(tagsSpec): checkRaisesSpec(tagsSpec, actual.sons[tagEffects], - "can have an unlisted effect: ", hints=off) + "can have an unlisted effect: ", hints=off, subtypeRelation) + let usesSpec = effectSpec(p, wUses) + if not isNil(usesSpec): + checkRaisesSpec(usesSpec, actual.sons[usesEffects], + "may use an unlisted global variable: ", hints=off, symbolPredicate) + if sfThread in disp.flags and notGcSafe(branch.typ): + localError(branch.info, "base method is GC-safe, but '$1' is not" % + branch.name.s) proc setEffectsForProcType*(t: PType, n: PNode) = var effects = t.n.sons[0] @@ -573,21 +641,26 @@ proc setEffectsForProcType*(t: PType, n: PNode) = let raisesSpec = effectSpec(n, wRaises) tagsSpec = effectSpec(n, wTags) - if not isNil(raisesSpec) or not isNil(tagsSpec): + usesSpec = effectSpec(n, wUses) + if not isNil(raisesSpec) or not isNil(tagsSpec) or not isNil(usesSpec): internalAssert effects.len == 0 newSeq(effects.sons, effectListLen) if not isNil(raisesSpec): effects.sons[exceptionEffects] = raisesSpec if not isNil(tagsSpec): effects.sons[tagEffects] = tagsSpec + if not isNil(usesSpec): + effects.sons[usesEffects] = usesSpec proc initEffects(effects: PNode; s: PSym; t: var TEffects) = newSeq(effects.sons, effectListLen) effects.sons[exceptionEffects] = newNodeI(nkArgList, s.info) effects.sons[tagEffects] = newNodeI(nkArgList, s.info) + effects.sons[usesEffects] = newNodeI(nkArgList, s.info) t.exc = effects.sons[exceptionEffects] t.tags = effects.sons[tagEffects] + t.uses = effects.sons[usesEffects] t.owner = s t.init = @[] t.guards = @[] @@ -602,7 +675,6 @@ proc trackProc*(s: PSym, body: PNode) = var t: TEffects initEffects(effects, s, t) track(t, body) - if not isEmptyType(s.typ.sons[0]) and tfNeedsInit in s.typ.sons[0].flags and s.kind in {skProc, skConverter, skMethod}: var res = s.ast.sons[resultPos].sym # get result symbol @@ -612,17 +684,27 @@ proc trackProc*(s: PSym, body: PNode) = let raisesSpec = effectSpec(p, wRaises) if not isNil(raisesSpec): checkRaisesSpec(raisesSpec, t.exc, "can raise an unlisted exception: ", - hints=on) + hints=on, subtypeRelation) # after the check, use the formal spec: effects.sons[exceptionEffects] = raisesSpec let tagsSpec = effectSpec(p, wTags) if not isNil(tagsSpec): checkRaisesSpec(tagsSpec, t.tags, "can have an unlisted effect: ", - hints=off) + hints=off, subtypeRelation) # after the check, use the formal spec: effects.sons[tagEffects] = tagsSpec - + + when trackGlobals: + let usesSpec = effectSpec(p, wUses) + if not isNil(usesSpec): + checkRaisesSpec(usesSpec, t.uses, + "uses an unlisted global variable: ", hints=on, symbolPredicate) + effects.sons[usesEffects] = usesSpec + if sfThread in s.flags and t.gcUnsafe: + localError(s.info, "'$1' is not GC-safe" % s.name.s) + if not t.gcUnsafe: s.typ.flags.incl tfGcSafe + proc trackTopLevelStmt*(module: PSym; n: PNode) = if n.kind in {nkPragma, nkMacroDef, nkTemplateDef, nkProcDef, nkTypeSection, nkConverterDef, nkMethodDef, nkIteratorDef}: |