Do not assume InstAlias operands appear after a blank

[rogfer01]

Summary

AsmWriterEmitter.cpp assumes that all operands of a printed alias
will appear after a blank. This assumption does not hold in the ARM
target.

[rogfer01]

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Regards

[rogfer01]

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[rogfer01]

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Kind regards,

[rogfer01]

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Thank you very much,

[rogfer01]

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Thank you.

[olista01]

LGTM

utils/TableGen/AsmWriterEmitter.cpp

void AsmWriterEmitter::EmitPrintAliasInstruction(raw_ostream &O) {
   O.indent(2) << "switch (MI->getOpcode()) {\n";
   O.indent(2) << "default: return false;\n";
   O << CasesO.str();
   O.indent(2) << "}\n\n";
 
   // Code that prints the alias, replacing the operands with the ones from the
   // MCInst.
   O << "  unsigned I = 0;\n";
-  O << "  while (AsmString[I] != ' ' && AsmString[I] != '\t' &&\n";
-  O << "         AsmString[I] != '\\0')\n";
+  O << "  while (AsmString[I] != ' ' && AsmString[I] != '\\t' &&\n";
+  O << "         AsmString[I] != '$' && AsmString[I] != '\\0')\n";
   O << "    ++I;\n";
   O << "  OS << '\\t' << StringRef(AsmString, I);\n";
 
   O << "  if (AsmString[I] != '\\0') {\n";
-  O << "    OS << '\\t';\n";
+  O << "    if (AsmString[I] == ' ' || AsmString[I] == '\\t')";
+  O << "      OS << '\\t';\n";
   O << "    do {\n";
   O << "      if (AsmString[I] == '$') {\n";
   O << "        ++I;\n";
   O << "        if (AsmString[I] == (char)0xff) {\n";
   O << "          ++I;\n";
   O << "          int OpIdx = AsmString[I++] - 1;\n";
   O << "          int PrintMethodIdx = AsmString[I++] - 1;\n";
   O << "          printCustomAliasOperand(MI, OpIdx, PrintMethodIdx, ";