PR28739: Check that integer values fit into 64 bits before extracting them as 64 bit values for pointer arithmetic.
This fixes various ways to tickle an assertion in constant expression
evaluation when using __int128. Longer term, we need to figure out what should
happen here: either any kind of overflow in offset calculation should result in
a non-constant value or we should truncate to 64 bits. In C++11 onwards, we're
effectively already checking for overflow because we strictly enforce array
bounds checks, but even there some forms of overflow can slip past undetected.
llvm-svn: 293568
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 92c8107..f2e7628 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -1460,9 +1460,17 @@
/// Sign- or zero-extend a value to 64 bits. If it's already 64 bits, just
/// return its existing value.
-static int64_t getExtValue(const APSInt &Value) {
- return Value.isSigned() ? Value.getSExtValue()
- : static_cast<int64_t>(Value.getZExtValue());
+static bool getExtValue(EvalInfo &Info, const Expr *E, const APSInt &Value,
+ int64_t &Result) {
+ if (Value.isSigned() ? Value.getMinSignedBits() > 64
+ : Value.getActiveBits() > 64) {
+ Info.FFDiag(E);
+ return false;
+ }
+
+ Result = Value.isSigned() ? Value.getSExtValue()
+ : static_cast<int64_t>(Value.getZExtValue());
+ return true;
}
/// Should this call expression be treated as a string literal?
@@ -3184,7 +3192,9 @@
return false;
}
- int64_t Offset = getExtValue(RHS.getInt());
+ int64_t Offset;
+ if (!getExtValue(Info, E, RHS.getInt(), Offset))
+ return false;
if (Opcode == BO_Sub)
Offset = -Offset;
@@ -5148,8 +5158,10 @@
if (!EvaluateInteger(E->getIdx(), Index, Info))
return false;
- return HandleLValueArrayAdjustment(Info, E, Result, E->getType(),
- getExtValue(Index));
+ int64_t Offset;
+ if (!getExtValue(Info, E, Index, Offset))
+ return false;
+ return HandleLValueArrayAdjustment(Info, E, Result, E->getType(), Offset);
}
bool LValueExprEvaluator::VisitUnaryDeref(const UnaryOperator *E) {
@@ -5415,7 +5427,9 @@
if (!EvaluateInteger(IExp, Offset, Info) || !EvalPtrOK)
return false;
- int64_t AdditionalOffset = getExtValue(Offset);
+ int64_t AdditionalOffset;
+ if (!getExtValue(Info, E, Offset, AdditionalOffset))
+ return false;
if (E->getOpcode() == BO_Sub)
AdditionalOffset = -AdditionalOffset;
@@ -5614,14 +5628,14 @@
APSInt Alignment;
if (!EvaluateInteger(E->getArg(1), Alignment, Info))
return false;
- CharUnits Align = CharUnits::fromQuantity(getExtValue(Alignment));
+ CharUnits Align = CharUnits::fromQuantity(Alignment.getZExtValue());
if (E->getNumArgs() > 2) {
APSInt Offset;
if (!EvaluateInteger(E->getArg(2), Offset, Info))
return false;
- int64_t AdditionalOffset = -getExtValue(Offset);
+ int64_t AdditionalOffset = -Offset.getZExtValue();
OffsetResult.Offset += CharUnits::fromQuantity(AdditionalOffset);
}
@@ -5638,12 +5652,11 @@
if (BaseAlignment < Align) {
Result.Designator.setInvalid();
- // FIXME: Quantities here cast to integers because the plural modifier
- // does not work on APSInts yet.
+ // FIXME: Add support to Diagnostic for long / long long.
CCEDiag(E->getArg(0),
diag::note_constexpr_baa_insufficient_alignment) << 0
- << (int) BaseAlignment.getQuantity()
- << (unsigned) getExtValue(Alignment);
+ << (unsigned)BaseAlignment.getQuantity()
+ << (unsigned)Align.getQuantity();
return false;
}
}
@@ -5651,18 +5664,14 @@
// The offset must also have the correct alignment.
if (OffsetResult.Offset.alignTo(Align) != OffsetResult.Offset) {
Result.Designator.setInvalid();
- APSInt Offset(64, false);
- Offset = OffsetResult.Offset.getQuantity();
- if (OffsetResult.Base)
- CCEDiag(E->getArg(0),
- diag::note_constexpr_baa_insufficient_alignment) << 1
- << (int) getExtValue(Offset) << (unsigned) getExtValue(Alignment);
- else
- CCEDiag(E->getArg(0),
- diag::note_constexpr_baa_value_insufficient_alignment)
- << Offset << (unsigned) getExtValue(Alignment);
-
+ (OffsetResult.Base
+ ? CCEDiag(E->getArg(0),
+ diag::note_constexpr_baa_insufficient_alignment) << 1
+ : CCEDiag(E->getArg(0),
+ diag::note_constexpr_baa_value_insufficient_alignment))
+ << (int)OffsetResult.Offset.getQuantity()
+ << (unsigned)Align.getQuantity();
return false;
}
@@ -7968,12 +7977,13 @@
// Handle cases like (unsigned long)&a + 4.
if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) {
Result = LHSVal;
- CharUnits AdditionalOffset =
- CharUnits::fromQuantity(RHSVal.getInt().getZExtValue());
+ int64_t Offset;
+ if (!getExtValue(Info, E, RHSVal.getInt(), Offset))
+ return false;
if (E->getOpcode() == BO_Add)
- Result.getLValueOffset() += AdditionalOffset;
+ Result.getLValueOffset() += CharUnits::fromQuantity(Offset);
else
- Result.getLValueOffset() -= AdditionalOffset;
+ Result.getLValueOffset() -= CharUnits::fromQuantity(Offset);
return true;
}
@@ -7981,8 +7991,10 @@
if (E->getOpcode() == BO_Add &&
RHSVal.isLValue() && LHSVal.isInt()) {
Result = RHSVal;
- Result.getLValueOffset() +=
- CharUnits::fromQuantity(LHSVal.getInt().getZExtValue());
+ int64_t Offset;
+ if (!getExtValue(Info, E, LHSVal.getInt(), Offset))
+ return false;
+ Result.getLValueOffset() += CharUnits::fromQuantity(Offset);
return true;
}