Add new form of ldr/str (immediate) to ARM integrated assembler.

src/IceAssemblerARM32.cpp

Index: src/IceAssemblerARM32.cpp
diff --git a/src/IceAssemblerARM32.cpp b/src/IceAssemblerARM32.cpp
index 3dbbb29f0be6fde664abdf2b6b64b253e1f8a8fa..8ef0517cb74e990b0c5a47f00f2741ee3c78e633 100644
--- a/src/IceAssemblerARM32.cpp
+++ b/src/IceAssemblerARM32.cpp
@@ -94,6 +94,10 @@ inline IValueT encodeGPRRegister(RegARM32::GPRRegister Rn) {
   return static_cast<IValueT>(Rn);
 }
 
+inline RegARM32::GPRRegister decodeGPRRegister(IValueT R) {
+  return static_cast<RegARM32::GPRRegister>(R);
+}
+
 inline bool isGPRRegisterDefined(RegARM32::GPRRegister R) {
   return R != RegARM32::Encoded_Not_GPR;
 }
@@ -138,7 +142,7 @@ inline bool isBitSet(IValueT Bit, IValueT Value) {
 
 // Returns the GPR register at given Shift in Value.
 inline RegARM32::GPRRegister getGPRReg(IValueT Shift, IValueT Value) {
-  return static_cast<RegARM32::GPRRegister>((Value >> Shift) & 0xF);
+  return decodeGPRRegister((Value >> Shift) & 0xF);
 }
 
 // The way an operand was decoded in functions decodeOperand and decodeAddress
@@ -160,7 +164,7 @@ enum DecodedResult {
 // Encodes iiiiitt0mmmm for data-processing (2nd) operands where iiiii=Imm5,
 // tt=Shift, and mmmm=Rm.
 IValueT encodeShiftRotateImm5(IValueT Rm, OperandARM32::ShiftKind Shift,
-                              IValueT imm5) {
+                              IOffsetT imm5) {
   (void)kShiftImmBits;
   assert(imm5 < (1 << kShiftImmBits));
   return (imm5 << kShiftImmShift) | (encodeShift(Shift) << kShiftShift) | Rm;
@@ -208,6 +212,18 @@ DecodedResult decodeAddress(const Operand *Opnd, IValueT &Value) {
                                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();
+    Value = decodeImmRegOffset(decodeGPRRegister(Var->getRegNum()),
+                               Offset->getValue(), Mem->getAddrMode());
+    return DecodedAsImmRegOffset;
+  }
   return CantDecode;
 }