// Try to fully compute Expr to an absolute value and if that fails produce
// a relocatable expr.
// FIXME: Should this be the behavior of EvaluateAsRelocatable itself?
static bool evaluate(const MCExpr &Expr, const MCAsmLayout &Layout,
const MCFixup &Fixup, MCValue &Target) {
if (Expr.EvaluateAsValue(Target, &Layout, &Fixup)) {
if (Target.isAbsolute())
return true;
}
return Expr.EvaluateAsRelocatable(Target, &Layout, &Fixup);
}
void MCStreamer::visitUsedExpr(const MCExpr &Expr) {
switch (Expr.getKind()) {
case MCExpr::Target:
cast<MCTargetExpr>(Expr).visitUsedExpr(*this);
break;
case MCExpr::Constant:
break;
case MCExpr::Binary: {
const MCBinaryExpr &BE = cast<MCBinaryExpr>(Expr);
visitUsedExpr(*BE.getLHS());
visitUsedExpr(*BE.getRHS());
break;
}
case MCExpr::SymbolRef:
visitUsedSymbol(cast<MCSymbolRefExpr>(Expr).getSymbol());
break;
case MCExpr::Unary:
visitUsedExpr(*cast<MCUnaryExpr>(Expr).getSubExpr());
break;
}
}
void MCObjectStreamer::emitFill(const MCExpr &NumValues, int64_t Size,
int64_t Expr, SMLoc Loc) {
int64_t IntNumValues;
// Do additional checking now if we can resolve the value.
if (NumValues.evaluateAsAbsolute(IntNumValues, getAssemblerPtr())) {
if (IntNumValues < 0) {
getContext().getSourceManager()->PrintMessage(
Loc, SourceMgr::DK_Warning,
"'.fill' directive with negative repeat count has no effect");
return;
}
// Emit now if we can for better errors.
int64_t NonZeroSize = Size > 4 ? 4 : Size;
Expr &= ~0ULL >> (64 - NonZeroSize * 8);
for (uint64_t i = 0, e = IntNumValues; i != e; ++i) {
EmitIntValue(Expr, NonZeroSize);
if (NonZeroSize < Size)
EmitIntValue(0, Size - NonZeroSize);
}
return;
}
// Otherwise emit as fragment.
MCDataFragment *DF = getOrCreateDataFragment();
flushPendingLabels(DF, DF->getContents().size());
assert(getCurrentSectionOnly() && "need a section");
insert(new MCFillFragment(Expr, Size, NumValues, Loc));
}
bool MCObjectStreamer::EmitRelocDirective(const MCExpr &Offset, StringRef Name,
const MCExpr *Expr, SMLoc Loc,
const MCSubtargetInfo &STI) {
int64_t OffsetValue;
if (!Offset.evaluateAsAbsolute(OffsetValue))
llvm_unreachable("Offset is not absolute");
if (OffsetValue < 0)
llvm_unreachable("Offset is negative");
MCDataFragment *DF = getOrCreateDataFragment(&STI);
flushPendingLabels(DF, DF->getContents().size());
Optional<MCFixupKind> MaybeKind = Assembler->getBackend().getFixupKind(Name);
if (!MaybeKind.hasValue())
return true;
MCFixupKind Kind = *MaybeKind;
if (Expr == nullptr)
Expr =
MCSymbolRefExpr::create(getContext().createTempSymbol(), getContext());
DF->getFixups().push_back(MCFixup::create(OffsetValue, Expr, Kind, Loc));
return false;
}
void MCObjectStreamer::emitFill(const MCExpr &NumValues, int64_t Size,
int64_t Expr, SMLoc Loc) {
int64_t IntNumValues;
if (!NumValues.evaluateAsAbsolute(IntNumValues, getAssembler())) {
getContext().reportError(Loc, "expected absolute expression");
return;
}
if (IntNumValues < 0) {
getContext().getSourceManager()->PrintMessage(
Loc, SourceMgr::DK_Warning,
"'.fill' directive with negative repeat count has no effect");
return;
}
MCStreamer::emitFill(IntNumValues, Size, Expr);
}
void MCObjectStreamer::emitFill(const MCExpr &NumBytes, uint64_t FillValue,
SMLoc Loc) {
MCDataFragment *DF = getOrCreateDataFragment();
flushPendingLabels(DF, DF->getContents().size());
int64_t IntNumBytes;
if (!NumBytes.evaluateAsAbsolute(IntNumBytes, getAssembler())) {
getContext().reportError(Loc, "expected absolute expression");
return;
}
if (IntNumBytes <= 0) {
getContext().reportError(Loc, "invalid number of bytes");
return;
}
emitFill(IntNumBytes, FillValue);
}