canEncodeNumber returns true if the architecture can encode an immediate for the given instruction.
(instr ssa.Value, number *ssa.Int)
| 10 | |
| 11 | // canEncodeNumber returns true if the architecture can encode an immediate for the given instruction. |
| 12 | func (f *Function) canEncodeNumber(instr ssa.Value, number *ssa.Int) bool { |
| 13 | switch instr := instr.(type) { |
| 14 | case *ssa.BinaryOp: |
| 15 | if number != instr.Right { |
| 16 | return false |
| 17 | } |
| 18 | |
| 19 | switch f.build.Arch { |
| 20 | case config.ARM: |
| 21 | if instr.Op.IsComparison() { |
| 22 | _, encodable := arm.CompareRegisterNumber(0, number.Int) |
| 23 | return encodable |
| 24 | } |
| 25 | |
| 26 | switch instr.Op { |
| 27 | case token.Add: |
| 28 | _, encodable := arm.AddRegisterNumber(0, 0, number.Int) |
| 29 | return encodable |
| 30 | case token.And: |
| 31 | _, encodable := arm.AndRegisterNumber(0, 0, number.Int) |
| 32 | return encodable |
| 33 | case token.Or: |
| 34 | _, encodable := arm.OrRegisterNumber(0, 0, number.Int) |
| 35 | return encodable |
| 36 | case token.Shl, token.Shr: |
| 37 | return number.Int >= 0 && number.Int <= 63 |
| 38 | case token.Sub: |
| 39 | _, encodable := arm.SubRegisterNumber(0, 0, number.Int) |
| 40 | return encodable |
| 41 | case token.Xor: |
| 42 | _, encodable := arm.XorRegisterNumber(0, 0, number.Int) |
| 43 | return encodable |
| 44 | } |
| 45 | case config.X86: |
| 46 | if instr.Op.IsComparison() { |
| 47 | return cpu.SizeInt(number.Int) <= 4 |
| 48 | } |
| 49 | |
| 50 | switch instr.Op { |
| 51 | case token.Add, token.And, token.Or, token.Sub, token.Xor: |
| 52 | return cpu.SizeInt(number.Int) <= 4 |
| 53 | case token.Shl, token.Shr: |
| 54 | return number.Int >= 0 && number.Int <= 63 |
| 55 | } |
| 56 | } |
| 57 | case *ssa.Load: |
| 58 | if instr.Memory.Index != number { |
| 59 | return false |
| 60 | } |
| 61 | |
| 62 | switch f.build.Arch { |
| 63 | case config.ARM: |
| 64 | if instr.Memory.Scale { |
| 65 | return number.Int >= 0 && number.Int <= 4095 |
| 66 | } else { |
| 67 | return number.Int >= -256 && number.Int <= 255 |
| 68 | } |
| 69 | case config.X86: |
no test coverage detected