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Add another IntExprEvaluator::Success overload to suck up remained of 

manual setting of the Result.

 - Idiom now enforces that result will always have correct width and
   type; this exposed three new bugs:

    o Enum constant decl value can have different width than type
      (PR3173).

    o EvaluateInteger should not run an IntExprEvaluator over
      non-integral expressions.

    o FloatExprEvaluate was not handling casts correctly (it was
      evaluating the cast in the IntExprEvaluator!).

llvm-svn: 65053
This commit is contained in:
Daniel Dunbar 2009-02-19 18:37:50 +00:00
parent 91668def8b
commit e3c92bc672
1 changed files with 49 additions and 43 deletions
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92
clang/lib/AST/ExprConstant.cpp
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@ -469,9 +469,20 @@ public:
return true; // still a constant.
}
bool Success(const llvm::APSInt &SI, const Expr *E) {
Result = SI;
assert(Result.isSigned() == E->getType()->isSignedIntegerType() &&
"Invalid evaluation result.");
assert(Result.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
"Invalid evaluation result.");
return true;
}
bool Success(const llvm::APInt &I, const Expr *E) {
Result = I;
Result.setIsUnsigned(E->getType()->isUnsignedIntegerType());
assert(Result.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
"Invalid evaluation result.");
return true;
}
@ -561,17 +572,22 @@ private:
} // end anonymous namespace
static bool EvaluateInteger(const Expr* E, APSInt &Result, EvalInfo &Info) {
if (!E->getType()->isIntegralType())
return false;
return IntExprEvaluator(Info, Result).Visit(const_cast<Expr*>(E));
}
bool IntExprEvaluator::VisitDeclRefExpr(const DeclRefExpr *E) {
// Enums are integer constant exprs.
if (const EnumConstantDecl *D = dyn_cast<EnumConstantDecl>(E->getDecl())) {
Result = D->getInitVal();
// FIXME: This is an ugly hack around the fact that enums don't set their
// signedness consistently; see PR3173
Result.setIsUnsigned(!E->getType()->isSignedIntegerType());
return true;
// signedness consistently; see PR3173.
APSInt SI = D->getInitVal();
SI.setIsUnsigned(!E->getType()->isSignedIntegerType());
// FIXME: This is an ugly hack around the fact that enums don't
// set their width (!?!) consistently; see PR3173.
SI.extOrTrunc(Info.Ctx.getIntWidth(E->getType()));
return Success(SI, E);
}
// In C++, const, non-volatile integers initialized with ICEs are ICEs.
@ -683,18 +699,16 @@ bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
// evaluating the RHS: 0 && X -> 0, 1 || X -> 1
if (lhsResult == (E->getOpcode() == BinaryOperator::LOr) ||
!lhsResult == (E->getOpcode() == BinaryOperator::LAnd)) {
Result = Info.Ctx.MakeIntValue(lhsResult, E->getType());
Info.ShortCircuit++;
bool rhsEvaluated = HandleConversionToBool(E->getRHS(), rhsResult, Info);
Info.ShortCircuit--;
if (rhsEvaluated)
return true;
// FIXME: Return an extension warning saying that the RHS could not be
// evaluated.
return true;
// if (!rhsEvaluated) ...
(void) rhsEvaluated;
return Success(lhsResult, E);
}
if (HandleConversionToBool(E->getRHS(), rhsResult, Info)) {
@ -839,29 +853,29 @@ bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
switch (E->getOpcode()) {
default:
return Error(E->getOperatorLoc(), diag::note_invalid_subexpr_in_ice, E);
case BinaryOperator::Mul: Result *= RHS; return true;
case BinaryOperator::Add: Result += RHS; return true;
case BinaryOperator::Sub: Result -= RHS; return true;
case BinaryOperator::And: Result &= RHS; return true;
case BinaryOperator::Xor: Result ^= RHS; return true;
case BinaryOperator::Or: Result |= RHS; return true;
case BinaryOperator::Mul: return Success(Result * RHS, E);
case BinaryOperator::Add: return Success(Result + RHS, E);
case BinaryOperator::Sub: return Success(Result - RHS, E);
case BinaryOperator::And: return Success(Result & RHS, E);
case BinaryOperator::Xor: return Success(Result ^ RHS, E);
case BinaryOperator::Or: return Success(Result | RHS, E);
case BinaryOperator::Div:
if (RHS == 0)
return Error(E->getOperatorLoc(), diag::note_expr_divide_by_zero, E);
Result /= RHS;
break;
return Success(Result / RHS, E);
case BinaryOperator::Rem:
if (RHS == 0)
return Error(E->getOperatorLoc(), diag::note_expr_divide_by_zero, E);
Result %= RHS;
break;
case BinaryOperator::Shl:
return Success(Result % RHS, E);
case BinaryOperator::Shl: {
// FIXME: Warn about out of range shift amounts!
Result <<= (unsigned)RHS.getLimitedValue(Result.getBitWidth()-1);
break;
case BinaryOperator::Shr:
Result >>= (unsigned)RHS.getLimitedValue(Result.getBitWidth()-1);
break;
unsigned SA = (unsigned) RHS.getLimitedValue(Result.getBitWidth()-1);
return Success(Result << SA, E);
}
case BinaryOperator::Shr: {
unsigned SA = (unsigned) RHS.getLimitedValue(Result.getBitWidth()-1);
return Success(Result >> SA, E);
}
case BinaryOperator::LT: return Success(Result < RHS, E);
case BinaryOperator::GT: return Success(Result > RHS, E);
@ -870,9 +884,6 @@ bool IntExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
case BinaryOperator::EQ: return Success(Result == RHS, E);
case BinaryOperator::NE: return Success(Result != RHS, E);
}
Result.setIsUnsigned(E->getType()->isUnsignedIntegerType());
return true;
}
bool IntExprEvaluator::VisitConditionalOperator(const ConditionalOperator *E) {
@ -991,20 +1002,15 @@ bool IntExprEvaluator::VisitUnaryOperator(const UnaryOperator *E) {
case UnaryOperator::Extension:
// FIXME: Should extension allow i-c-e extension expressions in its scope?
// If so, we could clear the diagnostic ID.
break;
return true;
case UnaryOperator::Plus:
// The result is always just the subexpr.
break;
return true;
case UnaryOperator::Minus:
Result = -Result;
break;
return Success(-Result, E);
case UnaryOperator::Not:
Result = ~Result;
break;
return Success(~Result, E);
}
Result.setIsUnsigned(E->getType()->isUnsignedIntegerType());
return true;
}
/// HandleCast - This is used to evaluate implicit or explicit casts where the
@ -1025,8 +1031,8 @@ bool IntExprEvaluator::VisitCastExpr(CastExpr *E) {
if (!Visit(SubExpr))
return false;
Result = HandleIntToIntCast(DestType, SubExpr->getType(), Result, Info.Ctx);
return true;
return Success(HandleIntToIntCast(DestType, SubExpr->getType(),
Result, Info.Ctx), E);
}
// FIXME: Clean this up!
@ -1048,8 +1054,8 @@ bool IntExprEvaluator::VisitCastExpr(CastExpr *E) {
if (!EvaluateFloat(SubExpr, F, Info))
return Error(E->getExprLoc(), diag::note_invalid_subexpr_in_ice, E);
Result = HandleFloatToIntCast(DestType, SubExpr->getType(), F, Info.Ctx);
return true;
return Success(HandleFloatToIntCast(DestType, SubExpr->getType(),
F, Info.Ctx), E);
}
//===----------------------------------------------------------------------===//
@ -1194,7 +1200,7 @@ bool FloatExprEvaluator::VisitCastExpr(CastExpr *E) {
if (SubExpr->getType()->isIntegralType()) {
APSInt IntResult;
if (!EvaluateInteger(E, IntResult, Info))
if (!EvaluateInteger(SubExpr, IntResult, Info))
return false;
Result = HandleIntToFloatCast(E->getType(), SubExpr->getType(),
IntResult, Info.Ctx);