[ARM] Add diag string for movw/movt immediates in assembly

[olista01]

Summary

This adds diagnostics for invalid immediate operands to the MOVW and MOVT instructions (ARM and Thumb).

This depends on D31607 (and it's dependencies), which added the mechanism to table-generate these diagnostic messages.

[rengolin]

LGTM. Thanks!

lib/Target/ARM/ARMInstrInfo.td

 // a relocatable expression.
 //
 // FIXME: This really needs a Thumb version separate from the ARM version.
 // While the range is the same, and can thus use the same match class,
 // the encoding is different so it should have a different encoder method.
 def Imm0_65535ExprAsmOperand: AsmOperandClass {
   let Name = "Imm0_65535Expr";
   let RenderMethod = "addImmOperands";
+  let DiagnosticString = "operand must be an immediate in the range [0,0xffff] or a relocatable expression";
 }
 
 def imm0_65535_expr : Operand<i32> {
   let EncoderMethod = "getHiLo16ImmOpValue";
   let ParserMatchClass = Imm0_65535ExprAsmOperand;
 }
 
 def Imm256_65535ExprAsmOperand: ImmAsmOperand<256,65535> { let Name = "Imm256_65535Expr"; }

test/MC/ARM/diagnostics.s

@ CHECK-ERRORS-V8: invalid instruction
         @ p10 and p11 are reserved for NEON
         mcr p10, #2, r5, c1, c1, #4
         mcrr p11, #8, r5, r4, c1
 @ CHECK-ERRORS: error: invalid operand for instruction
 @ CHECK-ERRORS: error: invalid operand for instruction
 
         @ Out of range immediate for MOV
         movw r9, 0x10000
-@ CHECK-ERRORS: error: invalid operand for instruction
+@ CHECK-ERRORS: error: operand must be an immediate in the range [0,0xffff] or a relocatable expression
 @ CHECK-ERRORS:        movw r9, 0x10000
 @ CHECK-ERRORS:                 ^
 
         @ Invalid 's' bit usage for MOVW
         movs r6, #0xffff
         movwseq r9, #0xffff
 @ CHECK-ERRORS: error: invalid operand for instruction
 @ CHECK-ERRORS: error: instruction 'movw' can not set flags, but 's' suffix specified
 
         @ Out of range immediate for MOVT
         movt r9, 0x10000
-@ CHECK-ERRORS: error: invalid operand for instruction
+@ CHECK-ERRORS: error: operand must be an immediate in the range [0,0xffff] or a relocatable expression
 @ CHECK-ERRORS:        movt r9, 0x10000
 @ CHECK-ERRORS:                 ^
 
         @ Out of range immediates for MRC/MRC2/MRRC/MRRC2
         mrc  p14, #8, r1, c1, c2, #4
         mrc  p14, #1, r1, c1, c2, #8
         mrc2  p14, #8, r1, c1, c2, #4
         mrc2  p14, #0, r1, c1, c2, #9

test/MC/ARM/thumb2-diagnostics.s

 @ CHECK-ERRORS: error: branch target out of range
 @ CHECK-ERRORS: error: branch target out of range
 @ CHECK-ERRORS: error: branch target out of range
 
 foo2:
         mov r0, foo2
         movw r0, foo2
         movt r0, foo2
+        movt r0, #0x10000
+        movt r0, #0x10000
 @ CHECK-ERRORS: error: invalid instruction, multiple near-miss encodings found
 @ CHECK-ERRORS: instruction requires: arm-mode
 @ CHECK-ERRORS: note: for one encoding: immediate operand must be in the range [256,65535]
 @ CHECK-ERRORS: immediate expression for mov requires :lower16: or :upper16
 @ CHECK-ERRORS:                  ^
 @ CHECK-ERRORS: immediate expression for mov requires :lower16: or :upper16
 @ CHECK-ERRORS:                  ^
+@ CHECK-ERRORS: error: operand must be an immediate in the range [0,0xffff] or a relocatable expression
+@ CHECK-ERRORS: error: operand must be an immediate in the range [0,0xffff] or a relocatable expression
 
         and sp, r1, #80008000
         and pc, r1, #80008000
 @ CHECK-ERRORS-V7: error: invalid instruction
 @ CHECK-ERRORS-V8: error: invalid operand for instruction
 @ CHECK-ERRORS: error: invalid instruction
 
         ssat r0, #1, r0, asr #32