cmd/asm/internal/arch: adds the missing type check for arm64 SXTB extension

Operands of memory type do not support SXTB extension. This CL adds this
missing check.

Change-Id: I1fa438dd314fc8aeb889637079cc67b538e83a89
Reviewed-on: https://go-review.googlesource.com/c/go/+/342769
Reviewed-by: eric fang <eric.fang@arm.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: eric fang <eric.fang@arm.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Michael Knyszek <mknyszek@google.com>

diff --git a/src/cmd/asm/internal/arch/arm64.go b/src/cmd/asm/internal/arch/arm64.go
index 40d828a1fea7485d3389c529f16180ecdd140bc7..24689c5ab17657816a67e7fe0b69a498e40d4c99 100644 (file)
--- a/src/cmd/asm/internal/arch/arm64.go
+++ b/src/cmd/asm/internal/arch/arm64.go
@@ -165,27 +165,21 @@ func ARM64RegisterExtension(a *obj.Addr, ext string, reg, num int16, isAmount, i
                }
        }
        if reg <= arm64.REG_R31 && reg >= arm64.REG_R0 {
+               if !isAmount {
+                       return errors.New("invalid register extension")
+               }
                switch ext {
                case "UXTB":
-                       if !isAmount {
-                               return errors.New("invalid register extension")
-                       }
                        if a.Type == obj.TYPE_MEM {
                                return errors.New("invalid shift for the register offset addressing mode")
                        }
                        a.Reg = arm64.REG_UXTB + Rnum
                case "UXTH":
-                       if !isAmount {
-                               return errors.New("invalid register extension")
-                       }
                        if a.Type == obj.TYPE_MEM {
                                return errors.New("invalid shift for the register offset addressing mode")
                        }
                        a.Reg = arm64.REG_UXTH + Rnum
                case "UXTW":
-                       if !isAmount {
-                               return errors.New("invalid register extension")
-                       }
                        // effective address of memory is a base register value and an offset register value.
                        if a.Type == obj.TYPE_MEM {
                                a.Index = arm64.REG_UXTW + Rnum
@@ -193,48 +187,33 @@ func ARM64RegisterExtension(a *obj.Addr, ext string, reg, num int16, isAmount, i
                                a.Reg = arm64.REG_UXTW + Rnum
                        }
                case "UXTX":
-                       if !isAmount {
-                               return errors.New("invalid register extension")
-                       }
                        if a.Type == obj.TYPE_MEM {
                                return errors.New("invalid shift for the register offset addressing mode")
                        }
                        a.Reg = arm64.REG_UXTX + Rnum
                case "SXTB":
-                       if !isAmount {
-                               return errors.New("invalid register extension")
+                       if a.Type == obj.TYPE_MEM {
+                               return errors.New("invalid shift for the register offset addressing mode")
                        }
                        a.Reg = arm64.REG_SXTB + Rnum
                case "SXTH":
-                       if !isAmount {
-                               return errors.New("invalid register extension")
-                       }
                        if a.Type == obj.TYPE_MEM {
                                return errors.New("invalid shift for the register offset addressing mode")
                        }
                        a.Reg = arm64.REG_SXTH + Rnum
                case "SXTW":
-                       if !isAmount {
-                               return errors.New("invalid register extension")
-                       }
                        if a.Type == obj.TYPE_MEM {
                                a.Index = arm64.REG_SXTW + Rnum
                        } else {
                                a.Reg = arm64.REG_SXTW + Rnum
                        }
                case "SXTX":
-                       if !isAmount {
-                               return errors.New("invalid register extension")
-                       }
                        if a.Type == obj.TYPE_MEM {
                                a.Index = arm64.REG_SXTX + Rnum
                        } else {
                                a.Reg = arm64.REG_SXTX + Rnum
                        }
                case "LSL":
-                       if !isAmount {
-                               return errors.New("invalid register extension")
-                       }
                        a.Index = arm64.REG_LSL + Rnum
                default:
                        return errors.New("unsupported general register extension type: " + ext)