+static std::pair<StringRef, StringRef>
+parseTwoOperandConstraint(StringRef S, ArrayRef<SMLoc> Loc) {
+ // Split via the '='.
+ std::pair<StringRef, StringRef> Ops = S.split('=');
+ if (Ops.second == "")
+ PrintFatalError(Loc, "missing '=' in two-operand alias constraint");
+ // Trim whitespace and the leading '$' on the operand names.
+ size_t start = Ops.first.find_first_of('$');
+ if (start == std::string::npos)
+ PrintFatalError(Loc, "expected '$' prefix on asm operand name");
+ Ops.first = Ops.first.slice(start + 1, std::string::npos);
+ size_t end = Ops.first.find_last_of(" \t");
+ Ops.first = Ops.first.slice(0, end);
+ // Now the second operand.
+ start = Ops.second.find_first_of('$');
+ if (start == std::string::npos)
+ PrintFatalError(Loc, "expected '$' prefix on asm operand name");
+ Ops.second = Ops.second.slice(start + 1, std::string::npos);
+ end = Ops.second.find_last_of(" \t");
+ Ops.first = Ops.first.slice(0, end);
+ return Ops;
+}
+
+void MatchableInfo::formTwoOperandAlias(StringRef Constraint) {
+ // Figure out which operands are aliased and mark them as tied.
+ std::pair<StringRef, StringRef> Ops =
+ parseTwoOperandConstraint(Constraint, TheDef->getLoc());
+
+ // Find the AsmOperands that refer to the operands we're aliasing.
+ int SrcAsmOperand = findAsmOperandNamed(Ops.first);
+ int DstAsmOperand = findAsmOperandNamed(Ops.second);
+ if (SrcAsmOperand == -1)
+ PrintFatalError(TheDef->getLoc(),
+ "unknown source two-operand alias operand '" +
+ Ops.first.str() + "'.");
+ if (DstAsmOperand == -1)
+ PrintFatalError(TheDef->getLoc(),
+ "unknown destination two-operand alias operand '" +
+ Ops.second.str() + "'.");
+
+ // Find the ResOperand that refers to the operand we're aliasing away
+ // and update it to refer to the combined operand instead.
+ for (unsigned i = 0, e = ResOperands.size(); i != e; ++i) {
+ ResOperand &Op = ResOperands[i];
+ if (Op.Kind == ResOperand::RenderAsmOperand &&
+ Op.AsmOperandNum == (unsigned)SrcAsmOperand) {
+ Op.AsmOperandNum = DstAsmOperand;
+ break;
+ }
+ }
+ // Remove the AsmOperand for the alias operand.
+ AsmOperands.erase(AsmOperands.begin() + SrcAsmOperand);
+ // Adjust the ResOperand references to any AsmOperands that followed
+ // the one we just deleted.
+ for (unsigned i = 0, e = ResOperands.size(); i != e; ++i) {
+ ResOperand &Op = ResOperands[i];
+ switch(Op.Kind) {
+ default:
+ // Nothing to do for operands that don't reference AsmOperands.
+ break;
+ case ResOperand::RenderAsmOperand:
+ if (Op.AsmOperandNum > (unsigned)SrcAsmOperand)
+ --Op.AsmOperandNum;
+ break;
+ case ResOperand::TiedOperand:
+ if (Op.TiedOperandNum > (unsigned)SrcAsmOperand)
+ --Op.TiedOperandNum;
+ break;
+ }
+ }
+}
+