+ const MCSymbolRefExpr *B = Target.getSymB();
+ if (B) {
+ uint64_t ValB;
+ if (!getLabelOffset(Layout, Asm.getSymbolData(B->getSymbol()), ReportError,
+ ValB))
+ return false;
+ Offset -= ValB;
+ }
+
+ Val = Offset;
+ return true;
+}
+
+bool MCAsmLayout::getSymbolOffset(const MCSymbolData *SD, uint64_t &Val) const {
+ return getSymbolOffsetImpl(*this, SD, false, Val);
+}
+
+uint64_t MCAsmLayout::getSymbolOffset(const MCSymbolData *SD) const {
+ uint64_t Val;
+ getSymbolOffsetImpl(*this, SD, true, Val);
+ return Val;
+}
+
+const MCSymbol *MCAsmLayout::getBaseSymbol(const MCSymbol &Symbol) const {
+ if (!Symbol.isVariable())
+ return &Symbol;
+
+ const MCExpr *Expr = Symbol.getVariableValue();
+ MCValue Value;
+ if (!Expr->evaluateAsValue(Value, *this))
+ llvm_unreachable("Invalid Expression");
+
+ const MCSymbolRefExpr *RefB = Value.getSymB();
+ if (RefB)
+ Assembler.getContext().reportFatalError(
+ SMLoc(), Twine("symbol '") + RefB->getSymbol().getName() +
+ "' could not be evaluated in a subtraction expression");
+
+ const MCSymbolRefExpr *A = Value.getSymA();
+ if (!A)
+ return nullptr;
+
+ const MCSymbol &ASym = A->getSymbol();
+ const MCAssembler &Asm = getAssembler();
+ const MCSymbolData &ASD = Asm.getSymbolData(ASym);
+ if (ASD.isCommon()) {
+ // FIXME: we should probably add a SMLoc to MCExpr.
+ Asm.getContext().reportFatalError(SMLoc(),
+ "Common symbol " + ASym.getName() +
+ " cannot be used in assignment expr");
+ }
+
+ return &ASym;