cmd/internal/obj/riscv: add check for invalid shift amount input

Current RISCV64 assembler do not check the invalid shift amount. This CL
adds the check to avoid generating invalid instructions.

Fixes #57755

Change-Id: If33877605e161baefd98c50db1f71641ca057507
Reviewed-on: https://go-review.googlesource.com/c/go/+/461755
Reviewed-by: Joel Sing <[email protected]>
Reviewed-by: Cherry Mui <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Than McIntosh <[email protected]>
Run-TryBot: Wayne Zuo <[email protected]>

src/cmd/asm/internal/asm/testdata/riscv64error.s

@@ -26,5 +26,17 @@ TEXT errors(SB),$0
  MOVD F0, F1, F2 // ERROR "illegal MOV instruction"
  MOV X10, X11, X12 // ERROR "illegal MOV instruction"
  MOVW X10, X11, X12 // ERROR "illegal MOV instruction"
+ SLLI $64, X5, X6 // ERROR "shift amount out of range 0 to 63"
+ SRLI $64, X5, X6 // ERROR "shift amount out of range 0 to 63"
+ SRAI $64, X5, X6 // ERROR "shift amount out of range 0 to 63"
+ SLLI $-1, X5, X6 // ERROR "shift amount out of range 0 to 63"
+ SRLI $-1, X5, X6 // ERROR "shift amount out of range 0 to 63"
+ SRAI $-1, X5, X6 // ERROR "shift amount out of range 0 to 63"
+ SLLIW $32, X5, X6 // ERROR "shift amount out of range 0 to 31"
+ SRLIW $32, X5, X6 // ERROR "shift amount out of range 0 to 31"
+ SRAIW $32, X5, X6 // ERROR "shift amount out of range 0 to 31"
+ SLLIW $-1, X5, X6 // ERROR "shift amount out of range 0 to 31"
+ SRLIW $-1, X5, X6 // ERROR "shift amount out of range 0 to 31"
+ SRAIW $-1, X5, X6 // ERROR "shift amount out of range 0 to 31"
 
  RET

src/cmd/internal/obj/riscv/obj.go

@@ -2146,6 +2146,16 @@ func instructionsForProg(p *obj.Prog) []*instruction {
  // FNEGD rs, rd -> FSGNJND rs, rs, rd
  ins.as = AFSGNJND
  ins.rs1 = uint32(p.From.Reg)
+
+ case ASLLI, ASRLI, ASRAI:
+ if ins.imm < 0 || ins.imm > 63 {
+ p.Ctxt.Diag("%v: shift amount out of range 0 to 63", p)
+ }
+
+ case ASLLIW, ASRLIW, ASRAIW:
+ if ins.imm < 0 || ins.imm > 31 {
+ p.Ctxt.Diag("%v: shift amount out of range 0 to 31", p)
+ }
  }
  return inss
 }