Fix base register for stack variables in ARM integrated assembler.

src/IceAssemblerARM32.cpp

 //===- subzero/src/IceAssemblerARM32.cpp - Assembler for ARM32 --*- C++ -*-===//
 //
 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // Modified by the Subzero authors.
 //
 //===----------------------------------------------------------------------===//
 //
@@ skipping 218 matching lines @@
 // Decodes memory address Opnd, and encodes that information into Value,
 // based on how ARM represents the address. Returns how the value was encoded.
 DecodedResult decodeAddress(const Operand *Opnd, IValueT &Value) {
   if (const auto *Var = llvm::dyn_cast<Variable>(Opnd)) {
     // Should be a stack variable, with an offset.
     if (Var->hasReg())
       return CantDecode;
     const IOffsetT Offset = Var->getStackOffset();
     if (!Utils::IsAbsoluteUint(12, Offset))
       return CantDecode;
-    Value = decodeImmRegOffset(RegARM32::Encoded_Reg_sp, Offset,
-                               OperandARM32Mem::Offset);
+    RegARM32::GPRRegister BaseReg = RegARM32::Encoded_Reg_sp;
+    if (const auto *StackVar = llvm::dyn_cast<StackVariable>(Var))
+      BaseReg = decodeGPRRegister(StackVar->getBaseRegNum());
+    Value = decodeImmRegOffset(BaseReg, Offset, OperandARM32Mem::Offset);
     return DecodedAsImmRegOffset;
   }
   if (const auto *Mem = llvm::dyn_cast<OperandARM32Mem>(Opnd)) {
     if (Mem->isRegReg())
       // TODO(kschimpf) Add this case.
       return CantDecode;
     Variable *Var = Mem->getBase();
     if (!Var->hasReg())
       return CantDecode;
     ConstantInteger32 *Offset = Mem->getOffset();
@@ skipping 729 matching lines @@
   //    sub{s}<c> sp, <Rn>, #<RotatedImm8>
   //
   // cccc0010010snnnnddddiiiiiiiiiiii where cccc=Cond, dddd=Rd, nnnn=Rn,
   // s=SetFlags and iiiiiiiiiiii=Src1Value defining RotatedImm8
   constexpr IValueT Sub = B1; // 0010
   emitType01(Sub, OpRd, OpRn, OpSrc1, SetFlags, Cond);
 }
 
 } // end of namespace ARM32
 } // end of namespace Ice