/// GetIntegerValue - Convert this numeric literal value to an APInt that
/// matches Val's input width. If there is an overflow, set Val to the low bits
/// of the result and return true. Otherwise, return false.
bool NumericLiteralParser::GetIntegerValue(llvm::APInt &Val) {
// Fast path: Compute a conservative bound on the maximum number of
// bits per digit in this radix. If we can't possibly overflow a
// uint64 based on that bound then do the simple conversion to
// integer. This avoids the expensive overflow checking below, and
// handles the common cases that matter (small decimal integers and
// hex/octal values which don't overflow).
const unsigned NumDigits = SuffixBegin - DigitsBegin;
if (alwaysFitsInto64Bits(radix, NumDigits)) {
uint64_t N = 0;
for (const char *Ptr = DigitsBegin; Ptr != SuffixBegin; ++Ptr)
if (!isDigitSeparator(*Ptr))
N = N * radix + llvm::hexDigitValue(*Ptr);
// This will truncate the value to Val's input width. Simply check
// for overflow by comparing.
Val = N;
return Val.getZExtValue() != N;
}
Val = 0;
const char *Ptr = DigitsBegin;
llvm::APInt RadixVal(Val.getBitWidth(), radix);
llvm::APInt CharVal(Val.getBitWidth(), 0);
llvm::APInt OldVal = Val;
bool OverflowOccurred = false;
while (Ptr < SuffixBegin) {
if (isDigitSeparator(*Ptr)) {
++Ptr;
continue;
}
unsigned C = llvm::hexDigitValue(*Ptr++);
// If this letter is out of bound for this radix, reject it.
assert(C < radix && "NumericLiteralParser ctor should have rejected this");
CharVal = C;
// Add the digit to the value in the appropriate radix. If adding in digits
// made the value smaller, then this overflowed.
OldVal = Val;
// Multiply by radix, did overflow occur on the multiply?
Val *= RadixVal;
OverflowOccurred |= Val.udiv(RadixVal) != OldVal;
// Add value, did overflow occur on the value?
// (a + b) ult b <=> overflow
Val += CharVal;
OverflowOccurred |= Val.ult(CharVal);
}
return OverflowOccurred;
}
bool MagicNumbersCheck::isIgnoredValue(const IntegerLiteral *Literal) const {
const llvm::APInt IntValue = Literal->getValue();
const int64_t Value = IntValue.getZExtValue();
if (Value == 0)
return true;
if (IgnorePowersOf2IntegerValues && IntValue.isPowerOf2())
return true;
return std::binary_search(IgnoredIntegerValues.begin(),
IgnoredIntegerValues.end(), Value);
}
