[X86][MS-compatability] allow MS TYPE/SIZE/LENGTH operators as a part of a compound expression

[coby]

Summary

This patch introduces X86AsmParser with the ability to handle the aforementioned ops within compound "MS" arithmetical expressions. Currently - only supported as a stand alone Operand, e.g.:
"TYPE X"
now allowed :
"4 + TYPE X * 128"

LLVM side: https://reviews.llvm.org/D31173

[rnk]

lgtm

cfe/trunk/test/CodeGen/ms-inline-asm.c

// CHECK: t20
   __asm mov eax, LENGTH foo
 // CHECK: mov eax, $$1
   __asm mov eax, LENGTH bar
 // CHECK: mov eax, $$1
   __asm mov eax, LENGTH _foo
 // CHECK: mov eax, $$4
   __asm mov eax, LENGTH _bar
 // CHECK: mov eax, $$2
+  __asm mov eax, [eax + LENGTH foo * 4]
+// CHECK: mov eax, [eax + $$1 * $$4]
 
   __asm mov eax, TYPE foo
 // CHECK: mov eax, $$4
   __asm mov eax, TYPE bar
 // CHECK: mov eax, $$1
   __asm mov eax, TYPE _foo
 // CHECK: mov eax, $$4
   __asm mov eax, TYPE _bar
 // CHECK: mov eax, $$1
+  __asm mov eax, [eax + TYPE foo * 4]
+// CHECK: mov eax, [eax + $$4 * $$4]
 
   __asm mov eax, SIZE foo
 // CHECK: mov eax, $$4
   __asm mov eax, SIZE bar
 // CHECK: mov eax, $$1
   __asm mov eax, SIZE _foo
 // CHECK: mov eax, $$16
+  __asm mov eax, [eax + SIZE _foo * 4]
+// CHECK: mov eax, [eax + $$16 * $$4]
   __asm mov eax, SIZE _bar
 // CHECK: mov eax, $$2
 // CHECK: "~{eax},~{dirflag},~{fpsr},~{flags}"()
+
 }
 
 void t21() {
   __asm {
     __asm push ebx
     __asm mov ebx, 07H
     __asm pop ebx
   }