MIPS: Adding a check for JAL argument in PIC mode to prevent crashing on getExpr (llvm#120356)

Only an Expr is supported by JAL.
Let's check it before getExpr.
llvm#80535

---------

Co-authored-by: Renat Idrisov <[email protected]>

Author: parsifal-47

llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp

@@ -2108,6 +2108,10 @@ bool MipsAsmParser::processInstruction(MCInst &Inst, SMLoc IDLoc,
   if ((Opcode == Mips::JAL || Opcode == Mips::JAL_MM) && inPicMode()) {
     warnIfNoMacro(IDLoc);
 
+    if (!Inst.getOperand(0).isExpr()) {
+      return Error(IDLoc, "unsupported constant in relocation");
+    }
+
     const MCExpr *JalExpr = Inst.getOperand(0).getExpr();
 
     // We can do this expansion if there's only 1 symbol in the argument