[AMDGPU][mc] Fix memory corruption uncovered by AddressSanitizer during coverage/smoke Gfx7/8 testing.

Coverage/smoke Gfx7/8 tests were committed r292922 but then reverted
by r292974 due to AddressSanitizer failure, which is fixed by this patch.
Tests to be re-committed soon.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293338 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Artem Tamazov

lib/Target/AMDGPU/AsmParser/AMDGPUAsmParser.cpp

@@ -2373,8 +2373,6 @@ void AMDGPUAsmParser::cvtDS(MCInst &Inst, const OperandVector &Operands) {
   }
 
   addOptionalImmOperand(Inst, Operands, OptionalIdx, AMDGPUOperand::ImmTyOffset);
-  addOptionalImmOperand(Inst, Operands, OptionalIdx, AMDGPUOperand::ImmTyGDS);
-
   if (!GDSOnly) {
     addOptionalImmOperand(Inst, Operands, OptionalIdx, AMDGPUOperand::ImmTyGDS);
   }

lib/Target/AMDGPU/Utils/AMDGPUBaseInfo.cpp

@@ -335,12 +335,14 @@ unsigned getMCReg(unsigned Reg, const MCSubtargetInfo &STI) {
 }
 
 bool isSISrcOperand(const MCInstrDesc &Desc, unsigned OpNo) {
+  assert(OpNo <= Desc.NumOperands);
   unsigned OpType = Desc.OpInfo[OpNo].OperandType;
   return OpType >= AMDGPU::OPERAND_SRC_FIRST &&
          OpType <= AMDGPU::OPERAND_SRC_LAST;
 }
 
 bool isSISrcFPOperand(const MCInstrDesc &Desc, unsigned OpNo) {
+  assert(OpNo <= Desc.NumOperands);
   unsigned OpType = Desc.OpInfo[OpNo].OperandType;
   switch (OpType) {
   case AMDGPU::OPERAND_REG_IMM_FP32:
@@ -356,6 +358,7 @@ bool isSISrcFPOperand(const MCInstrDesc &Desc, unsigned OpNo) {
 }
 
 bool isSISrcInlinableOperand(const MCInstrDesc &Desc, unsigned OpNo) {
+  assert(OpNo <= Desc.NumOperands);
   unsigned OpType = Desc.OpInfo[OpNo].OperandType;
   return OpType >= AMDGPU::OPERAND_REG_INLINE_C_FIRST &&
          OpType <= AMDGPU::OPERAND_REG_INLINE_C_LAST;
@@ -399,6 +402,7 @@ unsigned getRegBitWidth(const MCRegisterClass &RC) {
 
 unsigned getRegOperandSize(const MCRegisterInfo *MRI, const MCInstrDesc &Desc,
                            unsigned OpNo) {
+  assert(OpNo <= Desc.NumOperands);
   unsigned RCID = Desc.OpInfo[OpNo].RegClass;
   return getRegBitWidth(MRI->getRegClass(RCID)) / 8;
 }