[Sema] Add a 'Semantic' parameter to Expr::isKnownToHaveBooleanValue
Some clients of this function want to know about any expression that is known
to produce a 0/1 value, and others care about expressions that are semantically
boolean.
This fixes a -Wswitch-bool regression I introduced in 8bfb353bb33c, pointed out
by Chris Hamilton!
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index d5c35e5..e5bb8a7 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -127,11 +127,7 @@
return E;
}
-/// isKnownToHaveBooleanValue - Return true if this is an integer expression
-/// that is known to return 0 or 1. This happens for _Bool/bool expressions
-/// but also int expressions which are produced by things like comparisons in
-/// C.
-bool Expr::isKnownToHaveBooleanValue() const {
+bool Expr::isKnownToHaveBooleanValue(bool Semantic) const {
const Expr *E = IgnoreParens();
// If this value has _Bool type, it is obvious 0/1.
@@ -142,7 +138,7 @@
if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
switch (UO->getOpcode()) {
case UO_Plus:
- return UO->getSubExpr()->isKnownToHaveBooleanValue();
+ return UO->getSubExpr()->isKnownToHaveBooleanValue(Semantic);
case UO_LNot:
return true;
default:
@@ -152,8 +148,9 @@
// Only look through implicit casts. If the user writes
// '(int) (a && b)' treat it as an arbitrary int.
+ // FIXME: Should we look through any cast expression in !Semantic mode?
if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E))
- return CE->getSubExpr()->isKnownToHaveBooleanValue();
+ return CE->getSubExpr()->isKnownToHaveBooleanValue(Semantic);
if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
switch (BO->getOpcode()) {
@@ -172,27 +169,27 @@
case BO_Xor: // Bitwise XOR operator.
case BO_Or: // Bitwise OR operator.
// Handle things like (x==2)|(y==12).
- return BO->getLHS()->isKnownToHaveBooleanValue() &&
- BO->getRHS()->isKnownToHaveBooleanValue();
+ return BO->getLHS()->isKnownToHaveBooleanValue(Semantic) &&
+ BO->getRHS()->isKnownToHaveBooleanValue(Semantic);
case BO_Comma:
case BO_Assign:
- return BO->getRHS()->isKnownToHaveBooleanValue();
+ return BO->getRHS()->isKnownToHaveBooleanValue(Semantic);
}
}
if (const ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E))
- return CO->getTrueExpr()->isKnownToHaveBooleanValue() &&
- CO->getFalseExpr()->isKnownToHaveBooleanValue();
+ return CO->getTrueExpr()->isKnownToHaveBooleanValue(Semantic) &&
+ CO->getFalseExpr()->isKnownToHaveBooleanValue(Semantic);
if (isa<ObjCBoolLiteralExpr>(E))
return true;
if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E))
- return OVE->getSourceExpr()->isKnownToHaveBooleanValue();
+ return OVE->getSourceExpr()->isKnownToHaveBooleanValue(Semantic);
if (const FieldDecl *FD = E->getSourceBitField())
- if (FD->getType()->isUnsignedIntegerType() &&
+ if (!Semantic && FD->getType()->isUnsignedIntegerType() &&
!FD->getBitWidth()->isValueDependent() &&
FD->getBitWidthValue(FD->getASTContext()) == 1)
return true;