+/// \brief Helper method for \see EvaluateSymbolAdd().
+static void AttemptToFoldSymbolOffsetDifference(const MCAssembler *Asm,
+ const MCAsmLayout *Layout,
+ const SectionAddrMap *Addrs,
+ bool InSet,
+ const MCSymbolRefExpr *&A,
+ const MCSymbolRefExpr *&B,
+ int64_t &Addend) {
+ if (!A || !B)
+ return;
+
+ const MCSymbol &SA = A->getSymbol();
+ const MCSymbol &SB = B->getSymbol();
+
+ if (SA.isUndefined() || SB.isUndefined())
+ return;
+
+ if (!Asm->getWriter().IsSymbolRefDifferenceFullyResolved(*Asm, A, B, InSet))
+ return;
+
+ MCSymbolData &AD = Asm->getSymbolData(SA);
+ MCSymbolData &BD = Asm->getSymbolData(SB);
+
+ if (AD.getFragment() == BD.getFragment()) {
+ Addend += (AD.getOffset() - BD.getOffset());
+
+ // Pointers to Thumb symbols need to have their low-bit set to allow
+ // for interworking.
+ if (Asm->isThumbFunc(&SA))
+ Addend |= 1;
+
+ // Clear the symbol expr pointers to indicate we have folded these
+ // operands.
+ A = B = 0;
+ return;
+ }
+
+ if (!Layout)
+ return;
+
+ const MCSectionData &SecA = *AD.getFragment()->getParent();
+ const MCSectionData &SecB = *BD.getFragment()->getParent();
+
+ if ((&SecA != &SecB) && !Addrs)
+ return;
+
+ // Eagerly evaluate.
+ Addend += (Layout->getSymbolOffset(&Asm->getSymbolData(A->getSymbol())) -
+ Layout->getSymbolOffset(&Asm->getSymbolData(B->getSymbol())));
+ if (Addrs && (&SecA != &SecB))
+ Addend += (Addrs->lookup(&SecA) - Addrs->lookup(&SecB));
+
+ // Clear the symbol expr pointers to indicate we have folded these
+ // operands.
+ A = B = 0;
+}
+
+/// \brief Evaluate the result of an add between (conceptually) two MCValues.
+///
+/// This routine conceptually attempts to construct an MCValue:
+/// Result = (Result_A - Result_B + Result_Cst)
+/// from two MCValue's LHS and RHS where
+/// Result = LHS + RHS
+/// and
+/// Result = (LHS_A - LHS_B + LHS_Cst) + (RHS_A - RHS_B + RHS_Cst).
+///
+/// This routine attempts to aggresively fold the operands such that the result
+/// is representable in an MCValue, but may not always succeed.
+///
+/// \returns True on success, false if the result is not representable in an
+/// MCValue.
+
+/// NOTE: It is really important to have both the Asm and Layout arguments.
+/// They might look redundant, but this function can be used before layout
+/// is done (see the object streamer for example) and having the Asm argument
+/// lets us avoid relaxations early.
+static bool EvaluateSymbolicAdd(const MCAssembler *Asm,
+ const MCAsmLayout *Layout,
+ const SectionAddrMap *Addrs,
+ bool InSet,