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[Parse] Drop Swift3 support for conditional compilation condition #17789

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Merged
merged 1 commit into from
Jul 25, 2018
Merged

[Parse] Drop Swift3 support for conditional compilation condition #17789

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9 changes: 0 additions & 9 deletions include/swift/AST/DiagnosticsParse.def
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Original file line number Diff line number Diff line change
Expand Up @@ -1504,15 +1504,6 @@ ERROR(unsupported_platform_condition_argument,none,
(StringRef))
ERROR(unsupported_conditional_compilation_expression_type,none,
"invalid conditional compilation expression", ())
WARNING(swift3_unsupported_conditional_compilation_expression_type,none,
"ignoring invalid conditional compilation expression, "
"which will be rejected in future version of Swift", ())
WARNING(swift3_conditional_compilation_expression_compound,none,
"ignoring parentheses in compound name, "
"which will be rejected in future version of Swift", ())
WARNING(swift3_conditional_compilation_expression_precedence,none,
"future version of Swift have different rule for evaluating condition; "
"add parentheses to make the condition compatible with Swift4", ())
ERROR(unsupported_conditional_compilation_integer,none,
"'%0' is not a valid conditional compilation expression, use '%1'",
(StringRef, StringRef))
Expand Down
105 changes: 5 additions & 100 deletions lib/Parse/ParseIfConfig.cpp
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Expand Up @@ -67,17 +67,9 @@ class ValidateIfConfigCondition :
auto UDRE = dyn_cast<UnresolvedDeclRefExpr>(E);
if (!UDRE ||
!UDRE->hasName() ||
UDRE->getRefKind() != Kind)
UDRE->getRefKind() != Kind ||
UDRE->getName().isCompoundName())
return None;
if (UDRE->getName().isCompoundName()) {
if (!Ctx.isSwiftVersion3())
return None;
// Swift3 used to accept compound names; warn and return the basename.
D.diagnose(UDRE->getNameLoc().getLParenLoc(),
diag::swift3_conditional_compilation_expression_compound)
.fixItRemove({ UDRE->getNameLoc().getLParenLoc(),
UDRE->getNameLoc().getRParenLoc() });
}

return UDRE->getName().getBaseIdentifier().str();
}
Expand Down Expand Up @@ -155,59 +147,6 @@ class ValidateIfConfigCondition :
return LHS;
}

// In Swift3 mode, leave sequence as a sequence because it has strange
// evaluation rule. See 'EvaluateIfConfigCondition::visitSequenceExpr'.
Expr *validateSequence(ArrayRef<Expr *> &S) {
assert(Ctx.isSwiftVersion3());

SmallVector<Expr *, 3> Filtered;
SmallVector<unsigned, 2> AndIdxs;
Filtered.push_back(validate(S[0]));
S = S.slice(1);

while (!S.empty()) {
auto OpName = getDeclRefStr(S[0], DeclRefKind::BinaryOperator);
if (!OpName.hasValue() || (*OpName != "||" && *OpName != "&&")) {
// Warning and ignore in Swift3 mode.
D.diagnose(
S[0]->getLoc(),
diag::swift3_unsupported_conditional_compilation_expression_type)
.highlight({ S[0]->getLoc(), S[1]->getEndLoc() });
} else {
// Remember the start and end of '&&' sequence.
bool InAnd = (AndIdxs.size() & 1) == 1;
if ((*OpName == "&&" && !InAnd) || (*OpName == "||" && InAnd))
AndIdxs.push_back(Filtered.size() - 1);

Filtered.push_back(S[0]);
Filtered.push_back(validate(S[1]));
}
S = S.slice(2);
}
assert((Filtered.size() & 1) == 1);

// If the last OpName is '&&', close it with a parenthesis, except if the
// operators are '&&' only.
if ((1 == (AndIdxs.size() & 1)) && AndIdxs.back() > 0)
AndIdxs.push_back(Filtered.size() - 1);
// Emit fix-its to make this sequence compatilble with Swift >=4 even in
// Swift3 mode.
if (AndIdxs.size() >= 2) {
assert((AndIdxs.size() & 1) == 0);
auto diag = D.diagnose(
Filtered[AndIdxs[0]]->getStartLoc(),
diag::swift3_conditional_compilation_expression_precedence);
for (unsigned i = 0, e = AndIdxs.size(); i < e; i += 2) {
diag.fixItInsert(Filtered[AndIdxs[i]]->getStartLoc(), "(");
diag.fixItInsertAfter(Filtered[AndIdxs[i + 1]]->getEndLoc(), ")");
}
}

if (Filtered.size() == 1)
return Filtered[0];
return SequenceExpr::create(Ctx, Filtered);
}

public:
ValidateIfConfigCondition(ASTContext &Ctx, DiagnosticEngine &D)
: Ctx(Ctx), D(D), HasError(false) {}
Expand Down Expand Up @@ -369,14 +308,9 @@ class ValidateIfConfigCondition :
// Fold sequence expression for non-Swift3 mode.
Expr *visitSequenceExpr(SequenceExpr *E) {
ArrayRef<Expr*> Elts = E->getElements();
Expr *foldedExpr;
if (Ctx.isSwiftVersion3()) {
foldedExpr = validateSequence(Elts);
} else {
auto LHS = validate(Elts[0]);
Elts = Elts.slice(1);
foldedExpr = foldSequence(LHS, Elts);
}
Expr *foldedExpr = validate(Elts[0]);
Elts = Elts.slice(1);
foldedExpr = foldSequence(foldedExpr, Elts);
assert(Elts.empty());
return foldedExpr;
}
Expand Down Expand Up @@ -477,42 +411,13 @@ class EvaluateIfConfigCondition :
}

bool visitBinaryExpr(BinaryExpr *E) {
assert(!Ctx.isSwiftVersion3() && "BinaryExpr in Swift3 mode");
auto OpName = getDeclRefStr(E->getFn());
auto Args = E->getArg()->getElements();
if (OpName == "||") return visit(Args[0]) || visit(Args[1]);
if (OpName == "&&") return visit(Args[0]) && visit(Args[1]);
llvm_unreachable("unsupported binary operator");
}

bool visitSequenceExpr(SequenceExpr *E) {
assert(Ctx.isSwiftVersion3() && "SequenceExpr in non-Swift3 mode");
ArrayRef<Expr *> Elems = E->getElements();
auto Result = visit(Elems[0]);
Elems = Elems.slice(1);
while (!Elems.empty()) {
auto OpName = getDeclRefStr(Elems[0]);

if (OpName == "||") {
Result = Result || visit(Elems[1]);
if (Result)
// Note that this is the Swift3 behavior.
// e.g. 'false || true && false' evaluates to 'true'.
return true;
} else if (OpName == "&&") {
Result = Result && visit(Elems[1]);
if (!Result)
// Ditto.
// e.g. 'false && true || true' evaluates to 'false'.
return false;
} else {
llvm_unreachable("must be removed in validation phase");
}
Elems = Elems.slice(2);
}
return Result;
}

bool visitExpr(Expr *E) { llvm_unreachable("Unvalidated condition?"); }
};

Expand Down