Files
swift-mirror/lib/AST/ASTWalker.cpp
Chris Lattner b4fd6dd04a Change TopLevelCodeDecl to allow it to hold a sequence of different exprs and statements in one unit, wrapping them into a BraceStmt. This makes it more similar to other decls (e.g. funcdecl, ctor decls, etc) and will be useful for future sil work.
Unfortunately, this regresses the repl when expressions like (1,2) are entered. This is because the repl is violating some invariants (forming dags out of ASTs, making ASDAG's which upset the type checker).  I'm going to fix this next, but can't bring myself to do it in the same commit.



Swift SVN r4617
2013-04-05 22:33:14 +00:00

765 lines
18 KiB
C++

//===--- ASTWalker.cpp - AST Traversal ------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file implements Expr::walk and Stmt::walk.
//
//===----------------------------------------------------------------------===//
#include "swift/AST/ASTWalker.h"
#include "swift/AST/ASTVisitor.h"
#include "swift/AST/PrettyStackTrace.h"
using namespace swift;
void ASTWalker::anchor() {}
namespace {
/// Traversal - This class implements a simple expression/statement
/// recursive traverser which queries a user-provided walker class
/// on every node in an AST.
class Traversal : public ASTVisitor<Traversal, Expr*, Stmt*> {
friend class ASTVisitor<Traversal, Expr*, Stmt*>;
ASTWalker &Walker;
typedef ASTVisitor<Traversal, Expr*, Stmt*> inherited;
/// \brief RAII object that sets the parent of the walk context
/// appropriately.
class SetParentRAII {
ASTWalker &Walker;
decltype(ASTWalker::Parent) PriorParent;
public:
template<typename T>
SetParentRAII(ASTWalker &walker, T *newParent)
: Walker(walker), PriorParent(walker.Parent) {
walker.Parent = newParent;
}
~SetParentRAII() {
Walker.Parent = PriorParent;
}
};
Expr *visit(Expr *E) {
SetParentRAII SetParent(Walker, E);
return inherited::visit(E);
}
Stmt *visit(Stmt *S) {
SetParentRAII SetParent(Walker, S);
return inherited::visit(S);
}
Expr *visitErrorExpr(ErrorExpr *E) { return E; }
Expr *visitLiteralExpr(LiteralExpr *E) { return E; }
Expr *visitDeclRefExpr(DeclRefExpr *E) { return E; }
Expr *visitSuperRefExpr(SuperRefExpr *E) { return E; }
Expr *visitOtherConstructorDeclRefExpr(OtherConstructorDeclRefExpr *E) {
return E;
}
Expr *visitUnresolvedConstructorExpr(UnresolvedConstructorExpr *E) {
if (auto sub = doIt(E->getSubExpr())) {
E->setSubExpr(sub);
return E;
}
return nullptr;
}
Expr *visitOverloadedDeclRefExpr(OverloadedDeclRefExpr *E) { return E; }
Expr *visitOverloadedMemberRefExpr(OverloadedMemberRefExpr *E) {
if (auto base = doIt(E->getBase())) {
E->setBase(base);
return E;
}
return nullptr;
}
Expr *visitUnresolvedDeclRefExpr(UnresolvedDeclRefExpr *E) { return E; }
Expr *visitUnresolvedMemberExpr(UnresolvedMemberExpr *E) { return E; }
Expr *visitOpaqueValueExpr(OpaqueValueExpr *E) { return E; }
Expr *visitInterpolatedStringLiteralExpr(InterpolatedStringLiteralExpr *E) {
for (auto &Segment : E->getSegments()) {
if (Expr *Seg = doIt(Segment))
Segment = Seg;
else
return nullptr;
}
return E;
}
Expr *visitCollectionExpr(CollectionExpr *E) {
if (Expr *Sub = doIt(E->getSubExpr())) {
E->setSubExpr(Sub);
return E;
}
return nullptr;
}
Expr *visitMemberRefExpr(MemberRefExpr *E) {
if (Expr *Base = doIt(E->getBase())) {
E->setBase(Base);
return E;
}
return nullptr;
}
Expr *visitExistentialMemberRefExpr(ExistentialMemberRefExpr *E) {
if (Expr *Base = doIt(E->getBase())) {
E->setBase(Base);
return E;
}
return nullptr;
}
Expr *visitArchetypeMemberRefExpr(ArchetypeMemberRefExpr *E) {
if (Expr *Base = doIt(E->getBase())) {
E->setBase(Base);
return E;
}
return nullptr;
}
Expr *visitGenericMemberRefExpr(GenericMemberRefExpr *E) {
if (Expr *Base = doIt(E->getBase())) {
E->setBase(Base);
return E;
}
return nullptr;
}
Expr *visitParenExpr(ParenExpr *E) {
if (Expr *subExpr = doIt(E->getSubExpr())) {
E->setSubExpr(subExpr);
return E;
}
return nullptr;
}
Expr *visitTupleExpr(TupleExpr *E) {
for (unsigned i = 0, e = E->getNumElements(); i != e; ++i)
if (E->getElement(i)) {
if (Expr *Elt = doIt(E->getElement(i)))
E->setElement(i, Elt);
else
return nullptr;
}
return E;
}
Expr *visitSubscriptExpr(SubscriptExpr *E) {
if (Expr *Base = doIt(E->getBase()))
E->setBase(Base);
else
return nullptr;
if (Expr *Index = doIt(E->getIndex()))
E->setIndex(Index);
else
return nullptr;
return E;
}
Expr *visitExistentialSubscriptExpr(ExistentialSubscriptExpr *E) {
if (Expr *Base = doIt(E->getBase()))
E->setBase(Base);
else
return nullptr;
if (Expr *Index = doIt(E->getIndex()))
E->setIndex(Index);
else
return nullptr;
return E;
}
Expr *visitArchetypeSubscriptExpr(ArchetypeSubscriptExpr *E) {
if (Expr *Base = doIt(E->getBase()))
E->setBase(Base);
else
return nullptr;
if (Expr *Index = doIt(E->getIndex()))
E->setIndex(Index);
else
return nullptr;
return E;
}
Expr *visitGenericSubscriptExpr(GenericSubscriptExpr *E) {
if (Expr *Base = doIt(E->getBase()))
E->setBase(Base);
else
return nullptr;
if (Expr *Index = doIt(E->getIndex()))
E->setIndex(Index);
else
return nullptr;
return E;
}
Expr *visitOverloadedSubscriptExpr(OverloadedSubscriptExpr *E) { return E; }
Expr *visitUnresolvedDotExpr(UnresolvedDotExpr *E) {
if (!E->getBase())
return E;
if (Expr *E2 = doIt(E->getBase())) {
E->setBase(E2);
return E;
}
return nullptr;
}
Expr *visitUnresolvedSpecializeExpr(UnresolvedSpecializeExpr *E) {
if (!E->getSubExpr())
return E;
if (Expr *Sub = doIt(E->getSubExpr())) {
E->setSubExpr(Sub);
return E;
}
return nullptr;
}
Expr *visitTupleElementExpr(TupleElementExpr *E) {
if (Expr *E2 = doIt(E->getBase())) {
E->setBase(E2);
return E;
}
return nullptr;
}
Expr *visitImplicitConversionExpr(ImplicitConversionExpr *E) {
if (Expr *E2 = doIt(E->getSubExpr())) {
E->setSubExpr(E2);
return E;
}
return nullptr;
}
Expr *visitAddressOfExpr(AddressOfExpr *E) {
if (Expr *E2 = doIt(E->getSubExpr())) {
E->setSubExpr(E2);
return E;
}
return nullptr;
}
Expr *visitSequenceExpr(SequenceExpr *E) {
for (unsigned i = 0, e = E->getNumElements(); i != e; ++i)
if (Expr *Elt = doIt(E->getElement(i)))
E->setElement(i, Elt);
else
return nullptr;
return E;
}
Expr *visitNewArrayExpr(NewArrayExpr *E) {
for (auto &bound : E->getBounds()) {
// Ignore empty bounds.
if (!bound.Value) continue;
Expr *newValue = doIt(bound.Value);
if (!newValue) return nullptr;
bound.Value = newValue;
}
return E;
}
Expr *visitMetatypeExpr(MetatypeExpr *E) {
if (Expr *base = E->getBase()) {
if ((base = doIt(base)))
E->setBase(base);
else
return nullptr;
}
return E;
}
Expr *visitFuncExpr(FuncExpr *E) {
if (!E->getBody())
return E;
if (BraceStmt *S = cast_or_null<BraceStmt>(doIt(E->getBody()))) {
E->setBody(S);
return E;
}
return nullptr;
}
Expr *visitExplicitClosureExpr(ExplicitClosureExpr *E) {
if (Expr *E2 = doIt(E->getBody())) {
E->setBody(E2);
return E;
}
return nullptr;
}
Expr *visitImplicitClosureExpr(ImplicitClosureExpr *E) {
if (Expr *E2 = doIt(E->getBody())) {
E->setBody(E2);
return E;
}
return nullptr;
}
Expr *visitModuleExpr(ModuleExpr *E) { return E; }
Expr *visitApplyExpr(ApplyExpr *E) {
if (E->getFn()) {
Expr *E2 = doIt(E->getFn());
if (E2 == nullptr) return nullptr;
E->setFn(E2);
}
if (E->getArg()) {
Expr *E2 = doIt(E->getArg());
if (E2 == nullptr) return nullptr;
E->setArg(E2);
}
return E;
}
Expr *visitDotSyntaxBaseIgnoredExpr(DotSyntaxBaseIgnoredExpr *E) {
Expr *E2 = doIt(E->getLHS());
if (E2 == nullptr) return nullptr;
E->setLHS(E2);
E2 = doIt(E->getRHS());
if (E2 == nullptr) return nullptr;
E->setRHS(E2);
return E;
}
Expr *visitCoerceExpr(CoerceExpr *E) {
Expr *Sub = doIt(E->getSubExpr());
if (!Sub) return nullptr;
E->setSubExpr(Sub);
return E;
}
Expr *visitUncheckedDowncastExpr(UncheckedDowncastExpr *E) {
Expr *Sub = doIt(E->getSubExpr());
if (!Sub) return nullptr;
E->setSubExpr(Sub);
return E;
}
Expr *visitUncheckedSuperToArchetypeExpr(UncheckedSuperToArchetypeExpr *E) {
Expr *Sub = doIt(E->getSubExpr());
if (!Sub) return nullptr;
E->setSubExpr(Sub);
return E;
}
Expr *visitIsSubtypeExpr(IsSubtypeExpr *E) {
Expr *Sub = doIt(E->getSubExpr());
if (!Sub) return nullptr;
E->setSubExpr(Sub);
return E;
}
Expr *visitSuperIsArchetypeExpr(SuperIsArchetypeExpr *E) {
Expr *Sub = doIt(E->getSubExpr());
if (!Sub) return nullptr;
E->setSubExpr(Sub);
return E;
}
Expr *visitRebindThisInConstructorExpr(RebindThisInConstructorExpr *E) {
Expr *Sub = doIt(E->getSubExpr());
if (!Sub) return nullptr;
E->setSubExpr(Sub);
return E;
}
Expr *visitIfExpr(IfExpr *E) {
Expr *Cond = doIt(E->getCondExpr());
if (!Cond) return nullptr;
E->setCondExpr(Cond);
Expr *Then = doIt(E->getThenExpr());
if (!Then) return nullptr;
E->setThenExpr(Then);
Expr *Else = doIt(E->getElseExpr());
if (!Else) return nullptr;
E->setElseExpr(Else);
return E;
}
Stmt *visitBreakStmt(BreakStmt *BS) {
return BS;
}
Stmt *visitContinueStmt(ContinueStmt *CS) {
return CS;
}
Stmt *visitAssignStmt(AssignStmt *AS) {
if (Expr *E = doIt(AS->getDest()))
AS->setDest(E);
else
return nullptr;
if (Expr *E = doIt(AS->getSrc()))
AS->setSrc(E);
else
return nullptr;
return AS;
}
Stmt *visitBraceStmt(BraceStmt *BS) {
for (auto &Elem : BS->getElements()) {
if (Expr *SubExpr = Elem.dyn_cast<Expr*>()) {
if (Expr *E2 = doIt(SubExpr))
Elem = E2;
else
return nullptr;
continue;
}
if (Stmt *S = Elem.dyn_cast<Stmt*>()) {
if (Stmt *S2 = doIt(S))
Elem = S2;
else
return nullptr;
continue;
}
if (doIt(Elem.get<Decl*>()))
return nullptr;
}
return BS;
}
Stmt *visitReturnStmt(ReturnStmt *RS) {
if (!RS->hasResult())
return RS;
if (Expr *E = doIt(RS->getResult()))
RS->setResult(E);
else
return nullptr;
return RS;
}
Stmt *visitIfStmt(IfStmt *IS) {
if (Expr *E2 = doIt(IS->getCond()))
IS->setCond(E2);
else
return nullptr;
if (Stmt *S2 = doIt(IS->getThenStmt()))
IS->setThenStmt(S2);
else
return nullptr;
if (IS->getElseStmt()) {
if (Stmt *S2 = doIt(IS->getElseStmt()))
IS->setElseStmt(S2);
else
return nullptr;
}
return IS;
}
Stmt *visitWhileStmt(WhileStmt *WS) {
if (Expr *E2 = doIt(WS->getCond()))
WS->setCond(E2);
else
return nullptr;
if (Stmt *S2 = doIt(WS->getBody()))
WS->setBody(S2);
else
return nullptr;
return WS;
}
Stmt *visitDoWhileStmt(DoWhileStmt *DWS) {
if (Stmt *S2 = doIt(DWS->getBody()))
DWS->setBody(S2);
else
return nullptr;
if (Expr *E2 = doIt(DWS->getCond()))
DWS->setCond(E2);
else
return nullptr;
return DWS;
}
Stmt *visitForStmt(ForStmt *FS) {
// Visit any var decls in the initializer.
for (auto D : FS->getInitializerVarDecls())
if (doIt(D))
return nullptr;
if (Expr *E = FS->getInitializer().dyn_cast<Expr*>()) {
if ((E = doIt(E)))
FS->setInitializer(E);
else
return nullptr;
} else if (AssignStmt *S = FS->getInitializer().dyn_cast<AssignStmt*>()) {
if ((S = cast_or_null<AssignStmt>(doIt(S))))
FS->setInitializer(S);
else
return nullptr;
}
if (FS->getCond().isNonNull()) {
if (Expr *E2 = doIt(FS->getCond().get()))
FS->setCond(E2);
else
return nullptr;
}
if (Expr *E = FS->getIncrement().dyn_cast<Expr*>()) {
if ((E = doIt(E)))
FS->setIncrement(E);
else
return nullptr;
} else if (AssignStmt *S = FS->getIncrement().dyn_cast<AssignStmt*>()) {
if ((S = cast_or_null<AssignStmt>(doIt(S))))
FS->setIncrement(S);
else
return nullptr;
}
if (Stmt *S = doIt(FS->getBody()))
FS->setBody(S);
else
return nullptr;
return FS;
}
Stmt *visitForEachStmt(ForEachStmt *S) {
if (Expr *Container = S->getContainer()) {
if ((Container = doIt(Container)))
S->setContainer(Container);
else
return nullptr;
}
if (Stmt *Body = S->getBody()) {
if ((Body = doIt(Body)))
S->setBody(cast<BraceStmt>(Body));
else
return nullptr;
}
return S;
}
Stmt *visitSwitchStmt(SwitchStmt *S) {
if (Expr *newSubject = doIt(S->getSubjectExpr()))
S->setSubjectExpr(newSubject);
else
return nullptr;
for (CaseStmt *aCase : S->getCases()) {
if (Stmt *aStmt = doIt(aCase)) {
assert(aCase == aStmt && "switch case remap not supported");
} else
return nullptr;
}
return S;
}
Stmt *visitCaseStmt(CaseStmt *S) {
// If type-checking has built a condition expr for this case, walk it.
// The value exprs are just for source fidelity.
if (Expr *condExpr = S->getConditionExpr()) {
if (Expr *newCondExpr = doIt(condExpr))
S->setConditionExpr(newCondExpr);
else
return nullptr;
} else {
for (Expr *&valueExpr : S->getMutableValueExprs()) {
if (Expr *newExpr = doIt(valueExpr))
valueExpr = newExpr;
else
return nullptr;
}
}
if (Stmt *newBody = doIt(S->getBody()))
S->setBody(newBody);
else
return nullptr;
return S;
}
bool visitPatternVarGetSet(Pattern *P) {
switch (P->getKind()) {
case PatternKind::Paren:
return visitPatternVarGetSet(cast<ParenPattern>(P)->getSubPattern());
case PatternKind::Tuple:
for (auto &Elt : cast<TuplePattern>(P)->getFields())
if (visitPatternVarGetSet(Elt.getPattern()))
return true;
return false;
case PatternKind::Named:
if (VarDecl *Var = cast<NamedPattern>(P)->getDecl()) {
if (!Var->isProperty())
return false;
if (FuncDecl *Get = Var->getGetter()) {
if (doIt(Get))
return true;
}
if (FuncDecl *Set = Var->getSetter()) {
if (doIt(Set))
return true;
}
}
return false;
case PatternKind::Any:
return false;
case PatternKind::Typed:
return visitPatternVarGetSet(cast<TypedPattern>(P)->getSubPattern());
}
}
public:
Traversal(ASTWalker &walker) : Walker(walker) {}
Expr *doIt(Expr *E) {
// Do the pre-order visitation. If it returns false, we just
// skip entering subnodes of this tree.
if (!Walker.walkToExprPre(E))
return E;
// Otherwise, visit the children.
E = visit(E);
// If we didn't bail out, do post-order visitation.
if (E) E = Walker.walkToExprPost(E);
return E;
}
Stmt *doIt(Stmt *S) {
// Do the pre-order visitation. If it returns false, we just
// skip entering subnodes of this tree.
if (!Walker.walkToStmtPre(S))
return S;
// Otherwise, visit the children.
S = visit(S);
// If we didn't bail out, do post-order visitation.
if (S) S = Walker.walkToStmtPost(S);
return S;
}
/// Returns true on failure.
bool doIt(Decl *D) {
// Do the pre-order visitation. If it returns false, we just
// skip entering subnodes of this tree.
if (!Walker.walkToDeclPre(D))
return false;
if (PatternBindingDecl *PBD = dyn_cast<PatternBindingDecl>(D)) {
#if 0
if (visitPatternVarGetSet(PBD->getPattern()))
return true;
#endif
if (Expr *Init = PBD->getInit()) {
#ifndef NDEBUG
PrettyStackTraceDecl debugStack("walking into initializer for", PBD);
#endif
if (Expr *E2 = doIt(Init))
PBD->setInit(E2);
else
return true;
}
} else if (FuncDecl *FD = dyn_cast<FuncDecl>(D)) {
FuncExpr *Body = FD->getBody();
#ifndef NDEBUG
PrettyStackTraceDecl debugStack("walking into body of", FD);
#endif
if (FuncExpr *E2 = cast_or_null<FuncExpr>(doIt(Body)))
FD->setBody(E2);
else
return true;
} else if (ExtensionDecl *ED = dyn_cast<ExtensionDecl>(D)) {
for (Decl *M : ED->getMembers()) {
if (doIt(M))
return true;
}
} else if (OneOfDecl *OOD = dyn_cast<OneOfDecl>(D)) {
for (Decl *Member : OOD->getMembers())
if (doIt(Member))
return true;
} else if (StructDecl *SD = dyn_cast<StructDecl>(D)) {
for (Decl *Member : SD->getMembers())
if (doIt(Member))
return true;
} else if (ClassDecl *CD = dyn_cast<ClassDecl>(D)) {
for (Decl *Member : CD->getMembers())
if (doIt(Member))
return true;
} else if (TopLevelCodeDecl *TLCD = dyn_cast<TopLevelCodeDecl>(D)) {
if (BraceStmt *S = cast_or_null<BraceStmt>(doIt(TLCD->getBody())))
TLCD->setBody(S);
} else if (ConstructorDecl *CD = dyn_cast<ConstructorDecl>(D)) {
Stmt *S = CD->getBody();
if (S) {
S = doIt(S);
CD->setBody(cast<BraceStmt>(S));
}
} else if (DestructorDecl *DD = dyn_cast<DestructorDecl>(D)) {
Stmt *S = DD->getBody();
S = doIt(S);
DD->setBody(cast<BraceStmt>(S));
}
return !Walker.walkToDeclPost(D);
}
};
} // end anonymous namespace.
Expr *Expr::walk(ASTWalker &walker) {
return Traversal(walker).doIt(this);
}
Stmt *Stmt::walk(ASTWalker &walker) {
return Traversal(walker).doIt(this);
}
bool Decl::walk(ASTWalker &walker) {
return Traversal(walker).doIt(this);
}