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https://github.com/ziglang/zig.git
synced 2025-12-29 09:33:18 +00:00
stage2: add lowering of M encoding
Examples include jmp / call near with memory or register operand like `jmp [rax]`, or even RIP-relative `call [rip + 0x10]`.
This commit is contained in:
Jakub Konka
parent
1167e248ef
commit
9078cb0197
@ -304,25 +304,13 @@ fn mirJmpCall(emit: *Emit, tag: Tag, inst: Mir.Inst.Index) InnerError!void {
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});
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return;
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}
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const modrm_ext: u3 = switch (tag) {
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.jmp_near => 0x4,
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.call_near => 0x2,
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else => unreachable,
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};
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if (ops.reg1 == .none) {
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// JMP/CALL [imm]
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const imm = emit.mir.instructions.items(.data)[inst].imm;
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const encoder = try Encoder.init(emit.code, 7);
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encoder.opcode_1byte(0xff);
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encoder.modRm_SIBDisp0(modrm_ext);
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encoder.sib_disp32();
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encoder.imm32(imm);
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return;
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return lowerToMEnc(tag, RegisterOrMemory.mem(null, imm), emit.code);
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}
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// JMP/CALL reg
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const encoder = try Encoder.init(emit.code, 2);
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encoder.opcode_1byte(0xff);
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encoder.modRm_direct(modrm_ext, ops.reg1.lowId());
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return lowerToMEnc(tag, RegisterOrMemory.reg(ops.reg1), emit.code);
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}
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const CondType = enum {
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@ -628,7 +616,7 @@ inline fn getOpCode(tag: Tag, enc: Encoding) ?u8 {
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}
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}
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inline fn getModRmExt(tag: Tag) u3 {
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inline fn getModRmExt(tag: Tag) ?u3 {
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return switch (tag) {
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.adc => 0x2,
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.add => 0x0,
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@ -639,8 +627,9 @@ inline fn getModRmExt(tag: Tag) u3 {
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.sbb => 0x3,
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.cmp => 0x7,
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.mov => 0x0,
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.jmp_near => 0x4,
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.call_near => 0x2,
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else => unreachable,
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else => null,
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};
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}
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@ -692,6 +681,67 @@ fn lowerToDEnc(tag: Tag, imm: i32, code: *std.ArrayList(u8)) InnerError!void {
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encoder.imm32(imm);
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}
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fn lowerToMEnc(tag: Tag, reg_or_mem: RegisterOrMemory, code: *std.ArrayList(u8)) InnerError!void {
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const opc = getOpCode(tag, .m).?;
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const modrm_ext = getModRmExt(tag).?;
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switch (reg_or_mem) {
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.register => |reg| {
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if (reg.size() != 64) return error.EmitFail;
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const encoder = try Encoder.init(code, 3);
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encoder.rex(.{
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.w = false,
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.b = reg.isExtended(),
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});
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encoder.opcode_1byte(opc);
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encoder.modRm_direct(modrm_ext, reg.lowId());
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},
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.memory => |mem_op| {
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const encoder = try Encoder.init(code, 8);
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if (mem_op.reg) |reg| {
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if (reg.size() != 64) return error.EmitFail;
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encoder.rex(.{
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.w = false,
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.b = reg.isExtended(),
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});
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encoder.opcode_1byte(opc);
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if (reg.lowId() == 4) {
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if (mem_op.disp == 0) {
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encoder.modRm_SIBDisp0(modrm_ext);
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encoder.sib_base(reg.lowId());
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} else if (immOpSize(mem_op.disp) == 8) {
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encoder.modRm_SIBDisp8(modrm_ext);
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encoder.sib_baseDisp8(reg.lowId());
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encoder.disp8(@intCast(i8, mem_op.disp));
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} else {
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encoder.modRm_SIBDisp32(modrm_ext);
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encoder.sib_baseDisp32(reg.lowId());
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encoder.disp32(mem_op.disp);
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}
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} else {
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if (mem_op.disp == 0) {
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encoder.modRm_indirectDisp0(modrm_ext, reg.lowId());
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} else if (immOpSize(mem_op.disp) == 8) {
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encoder.modRm_indirectDisp8(modrm_ext, reg.lowId());
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encoder.disp8(@intCast(i8, mem_op.disp));
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} else {
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encoder.modRm_indirectDisp32(modrm_ext, reg.lowId());
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encoder.disp32(mem_op.disp);
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}
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}
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} else {
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encoder.opcode_1byte(opc);
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if (mem_op.rip) {
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encoder.modRm_RIPDisp32(modrm_ext);
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} else {
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encoder.modRm_SIBDisp0(modrm_ext);
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encoder.sib_disp32();
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}
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encoder.disp32(mem_op.disp);
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}
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},
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}
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}
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fn lowerToTdEnc(tag: Tag, moffs: i64, reg: Register, code: *std.ArrayList(u8)) InnerError!void {
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return lowerToTdFdEnc(tag, reg, moffs, code, true);
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}
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@ -772,7 +822,7 @@ fn lowerToOiEnc(tag: Tag, reg: Register, imm: i64, code: *std.ArrayList(u8)) Inn
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fn lowerToMiEnc(tag: Tag, reg_or_mem: RegisterOrMemory, imm: i32, code: *std.ArrayList(u8)) InnerError!void {
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var opc = getOpCode(tag, .mi).?;
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const modrm_ext = getModRmExt(tag);
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const modrm_ext = getModRmExt(tag).?;
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switch (reg_or_mem) {
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.register => |dst_reg| {
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if (dst_reg.size() == 8) {
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@ -819,16 +869,25 @@ fn lowerToMiEnc(tag: Tag, reg_or_mem: RegisterOrMemory, imm: i32, code: *std.Arr
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.b = dst_reg.isExtended(),
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});
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encoder.opcode_1byte(opc);
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if (dst_mem.disp == 0) {
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encoder.modRm_indirectDisp0(modrm_ext, dst_reg.lowId());
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} else if (immOpSize(dst_mem.disp) == 8) {
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encoder.modRm_indirectDisp8(modrm_ext, dst_reg.lowId());
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encoder.disp8(@intCast(i8, dst_mem.disp));
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} else {
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if (dst_reg.lowId() == 4) {
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if (dst_reg.lowId() == 4) {
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if (dst_mem.disp == 0) {
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encoder.modRm_SIBDisp0(modrm_ext);
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encoder.sib_base(dst_reg.lowId());
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} else if (immOpSize(dst_mem.disp) == 8) {
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encoder.modRm_SIBDisp8(modrm_ext);
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encoder.sib_baseDisp8(dst_reg.lowId());
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encoder.disp8(@intCast(i8, dst_mem.disp));
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} else {
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encoder.modRm_SIBDisp32(modrm_ext);
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encoder.sib_baseDisp32(dst_reg.lowId());
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encoder.disp32(dst_mem.disp);
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}
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} else {
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if (dst_mem.disp == 0) {
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encoder.modRm_indirectDisp0(modrm_ext, dst_reg.lowId());
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} else if (immOpSize(dst_mem.disp) == 8) {
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encoder.modRm_indirectDisp8(modrm_ext, dst_reg.lowId());
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encoder.disp8(@intCast(i8, dst_mem.disp));
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} else {
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encoder.modRm_indirectDisp32(modrm_ext, dst_reg.lowId());
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encoder.disp32(dst_mem.disp);
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@ -886,16 +945,25 @@ fn lowerToRmEnc(
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.b = src_reg.isExtended(),
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});
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encoder.opcode_1byte(opc);
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if (src_mem.disp == 0) {
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encoder.modRm_indirectDisp0(reg.lowId(), src_reg.lowId());
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} else if (immOpSize(src_mem.disp) == 8) {
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encoder.modRm_indirectDisp8(reg.lowId(), src_reg.lowId());
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encoder.disp8(@intCast(i8, src_mem.disp));
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} else {
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if (src_reg.lowId() == 4) {
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if (src_reg.lowId() == 4) {
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if (src_mem.disp == 0) {
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encoder.modRm_SIBDisp0(reg.lowId());
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encoder.sib_base(src_reg.lowId());
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} else if (immOpSize(src_mem.disp) == 8) {
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encoder.modRm_SIBDisp8(reg.lowId());
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encoder.sib_baseDisp8(src_reg.lowId());
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encoder.disp8(@intCast(i8, src_mem.disp));
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} else {
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encoder.modRm_SIBDisp32(reg.lowId());
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encoder.sib_baseDisp32(src_reg.lowId());
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encoder.disp32(src_mem.disp);
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}
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} else {
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if (src_mem.disp == 0) {
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encoder.modRm_indirectDisp0(reg.lowId(), src_reg.lowId());
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} else if (immOpSize(src_mem.disp) == 8) {
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encoder.modRm_indirectDisp8(reg.lowId(), src_reg.lowId());
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encoder.disp8(@intCast(i8, src_mem.disp));
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} else {
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encoder.modRm_indirectDisp32(reg.lowId(), src_reg.lowId());
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encoder.disp32(src_mem.disp);
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@ -960,16 +1028,25 @@ fn lowerToMrEnc(
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.b = dst_reg.isExtended(),
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});
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encoder.opcode_1byte(opc);
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if (dst_mem.disp == 0) {
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encoder.modRm_indirectDisp0(reg.lowId(), dst_reg.lowId());
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} else if (immOpSize(dst_mem.disp) == 8) {
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encoder.modRm_indirectDisp8(reg.lowId(), dst_reg.lowId());
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encoder.disp8(@intCast(i8, dst_mem.disp));
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} else {
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if (dst_reg.lowId() == 4) {
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if (dst_reg.lowId() == 4) {
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if (dst_mem.disp == 0) {
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encoder.modRm_SIBDisp0(reg.lowId());
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encoder.sib_base(dst_reg.lowId());
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} else if (immOpSize(dst_mem.disp) == 8) {
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encoder.modRm_SIBDisp8(reg.lowId());
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encoder.sib_baseDisp8(dst_reg.lowId());
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encoder.disp8(@intCast(i8, dst_mem.disp));
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} else {
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encoder.modRm_SIBDisp32(reg.lowId());
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encoder.sib_baseDisp32(dst_reg.lowId());
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encoder.disp32(dst_mem.disp);
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}
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} else {
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if (dst_mem.disp == 0) {
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encoder.modRm_indirectDisp0(reg.lowId(), dst_reg.lowId());
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} else if (immOpSize(dst_mem.disp) == 8) {
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encoder.modRm_indirectDisp8(reg.lowId(), dst_reg.lowId());
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encoder.disp8(@intCast(i8, dst_mem.disp));
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} else {
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encoder.modRm_indirectDisp32(reg.lowId(), dst_reg.lowId());
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encoder.disp32(dst_mem.disp);
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@ -1099,7 +1176,7 @@ fn mirArithScaleDst(emit: *Emit, tag: Tag, inst: Mir.Inst.Index) InnerError!void
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if (ops.reg2 == .none) {
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// OP [reg1 + scale*rax + 0], imm32
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var opc = getOpCode(tag, .mi).?;
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const modrm_ext = getModRmExt(tag);
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const modrm_ext = getModRmExt(tag).?;
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if (ops.reg1.size() == 8) {
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opc -= 1;
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}
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@ -1153,7 +1230,7 @@ fn mirArithScaleImm(emit: *Emit, tag: Tag, inst: Mir.Inst.Index) InnerError!void
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if (ops.reg1.size() == 8) {
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opc -= 1;
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}
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const modrm_ext = getModRmExt(tag);
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const modrm_ext = getModRmExt(tag).?;
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const encoder = try Encoder.init(emit.code, 2);
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encoder.rex(.{
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.w = ops.reg1.size() == 64,
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@ -1641,3 +1718,24 @@ test "lower FD/TD encoding" {
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try lowerToFdEnc(.mov, .al, 0x10, code.buffer());
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try expectEqualHexStrings("\xa0\x10", code.emitted(), "mov al, ds:0x10");
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}
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test "lower M encoding" {
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var code = TestEmitCode.init();
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defer code.deinit();
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try lowerToMEnc(.jmp_near, RegisterOrMemory.reg(.r12), code.buffer());
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try expectEqualHexStrings("\x41\xFF\xE4", code.emitted(), "jmp r12");
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try lowerToMEnc(.jmp_near, RegisterOrMemory.mem(.r12, 0), code.buffer());
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try expectEqualHexStrings("\x41\xFF\x24\x24", code.emitted(), "jmp qword ptr [r12]");
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try lowerToMEnc(.jmp_near, RegisterOrMemory.mem(.r12, 0x10), code.buffer());
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try expectEqualHexStrings("\x41\xFF\x64\x24\x10", code.emitted(), "jmp qword ptr [r12 + 0x10]");
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try lowerToMEnc(.jmp_near, RegisterOrMemory.mem(.r12, 0x1000), code.buffer());
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try expectEqualHexStrings(
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"\x41\xFF\xA4\x24\x00\x10\x00\x00",
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code.emitted(),
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"jmp qword ptr [r12 + 0x1000]",
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);
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try lowerToMEnc(.jmp_near, RegisterOrMemory.rip(0x10), code.buffer());
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try expectEqualHexStrings("\xFF\x25\x10\x00\x00\x00", code.emitted(), "jmp qword ptr [rip + 0x10]");
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try lowerToMEnc(.jmp_near, RegisterOrMemory.mem(null, 0x10), code.buffer());
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try expectEqualHexStrings("\xFF\x24\x25\x10\x00\x00\x00", code.emitted(), "jmp qword ptr [ds:0x10]");
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}
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