5 use rustc_ast::ast::{InlineAsmOptions, InlineAsmTemplatePiece};
6 use rustc_middle::mir::InlineAsmOperand;
7 use rustc_target::asm::*;
9 pub(crate) fn codegen_inline_asm<'tcx>(
10 fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
12 template: &[InlineAsmTemplatePiece],
13 operands: &[InlineAsmOperand<'tcx>],
14 options: InlineAsmOptions,
16 // FIXME add .eh_frame unwind info directives
18 if template.is_empty() {
23 let mut slot_size = Size::from_bytes(0);
24 let mut clobbered_regs = Vec::new();
25 let mut inputs = Vec::new();
26 let mut outputs = Vec::new();
28 let mut new_slot = |reg_class: InlineAsmRegClass| {
29 let reg_size = reg_class
30 .supported_types(InlineAsmArch::X86_64)
32 .map(|(ty, _)| ty.size())
35 let align = rustc_target::abi::Align::from_bytes(reg_size.bytes()).unwrap();
36 slot_size = slot_size.align_to(align);
37 let offset = slot_size;
38 slot_size += reg_size;
42 // FIXME overlap input and output slots to save stack space
43 for operand in operands {
45 InlineAsmOperand::In { reg, ref value } => {
46 let reg = expect_reg(reg);
47 clobbered_regs.push((reg, new_slot(reg.reg_class())));
50 new_slot(reg.reg_class()),
51 crate::base::trans_operand(fx, value).load_scalar(fx),
54 InlineAsmOperand::Out {
59 let reg = expect_reg(reg);
60 clobbered_regs.push((reg, new_slot(reg.reg_class())));
61 if let Some(place) = place {
64 new_slot(reg.reg_class()),
65 crate::base::trans_place(fx, place),
69 InlineAsmOperand::InOut {
75 let reg = expect_reg(reg);
76 clobbered_regs.push((reg, new_slot(reg.reg_class())));
79 new_slot(reg.reg_class()),
80 crate::base::trans_operand(fx, in_value).load_scalar(fx),
82 if let Some(out_place) = out_place {
85 new_slot(reg.reg_class()),
86 crate::base::trans_place(fx, out_place),
90 InlineAsmOperand::Const { value: _ } => todo!(),
91 InlineAsmOperand::SymFn { value: _ } => todo!(),
92 InlineAsmOperand::SymStatic { def_id: _ } => todo!(),
96 let inline_asm_index = fx.inline_asm_index;
97 fx.inline_asm_index += 1;
98 let asm_name = format!(
100 fx.tcx.symbol_name(fx.instance).name,
104 let generated_asm = generate_asm_wrapper(
106 InlineAsmArch::X86_64,
113 fx.cx.global_asm.push_str(&generated_asm);
115 call_inline_asm(fx, &asm_name, slot_size, inputs, outputs);
118 fn generate_asm_wrapper(
121 options: InlineAsmOptions,
122 template: &[InlineAsmTemplatePiece],
123 clobbered_regs: Vec<(InlineAsmReg, Size)>,
124 inputs: &[(InlineAsmReg, Size, Value)],
125 outputs: &[(InlineAsmReg, Size, CPlace<'_>)],
127 let mut generated_asm = String::new();
128 writeln!(generated_asm, ".globl {}", asm_name).unwrap();
129 writeln!(generated_asm, ".type {},@function", asm_name).unwrap();
132 ".section .text.{},\"ax\",@progbits",
136 writeln!(generated_asm, "{}:", asm_name).unwrap();
138 generated_asm.push_str(".intel_syntax noprefix\n");
139 generated_asm.push_str(" push rbp\n");
140 generated_asm.push_str(" mov rbp,rdi\n");
142 // Save clobbered registers
143 if !options.contains(InlineAsmOptions::NORETURN) {
144 // FIXME skip registers saved by the calling convention
145 for &(reg, offset) in &clobbered_regs {
146 save_register(&mut generated_asm, arch, reg, offset);
150 // Write input registers
151 for &(reg, offset, _value) in inputs {
152 restore_register(&mut generated_asm, arch, reg, offset);
155 if options.contains(InlineAsmOptions::ATT_SYNTAX) {
156 generated_asm.push_str(".att_syntax\n");
159 // The actual inline asm
160 for piece in template {
162 InlineAsmTemplatePiece::String(s) => {
163 generated_asm.push_str(s);
165 InlineAsmTemplatePiece::Placeholder {
172 generated_asm.push('\n');
174 if options.contains(InlineAsmOptions::ATT_SYNTAX) {
175 generated_asm.push_str(".intel_syntax noprefix\n");
178 if !options.contains(InlineAsmOptions::NORETURN) {
179 // Read output registers
180 for &(reg, offset, _place) in outputs {
181 save_register(&mut generated_asm, arch, reg, offset);
184 // Restore clobbered registers
185 for &(reg, offset) in clobbered_regs.iter().rev() {
186 restore_register(&mut generated_asm, arch, reg, offset);
189 generated_asm.push_str(" pop rbp\n");
190 generated_asm.push_str(" ret\n");
192 generated_asm.push_str(" ud2\n");
195 generated_asm.push_str(".att_syntax\n");
196 writeln!(generated_asm, ".size {name}, .-{name}", name = asm_name).unwrap();
197 generated_asm.push_str(".text\n");
198 generated_asm.push_str("\n\n");
203 fn call_inline_asm<'tcx>(
204 fx: &mut FunctionCx<'_, 'tcx, impl Backend>,
207 inputs: Vec<(InlineAsmReg, Size, Value)>,
208 outputs: Vec<(InlineAsmReg, Size, CPlace<'tcx>)>,
210 let stack_slot = fx.bcx.func.create_stack_slot(StackSlotData {
211 kind: StackSlotKind::ExplicitSlot,
213 size: u32::try_from(slot_size.bytes()).unwrap(),
215 #[cfg(debug_assertions)]
216 fx.add_comment(stack_slot, "inline asm scratch slot");
218 let inline_asm_func = fx
225 call_conv: CallConv::SystemV,
226 params: vec![AbiParam::new(fx.pointer_type)],
231 let inline_asm_func = fx
234 .declare_func_in_func(inline_asm_func, &mut fx.bcx.func);
235 #[cfg(debug_assertions)]
236 fx.add_comment(inline_asm_func, asm_name);
238 for (_reg, offset, value) in inputs {
241 .stack_store(value, stack_slot, i32::try_from(offset.bytes()).unwrap());
244 let stack_slot_addr = fx.bcx.ins().stack_addr(fx.pointer_type, stack_slot, 0);
245 fx.bcx.ins().call(inline_asm_func, &[stack_slot_addr]);
247 for (_reg, offset, place) in outputs {
248 let ty = fx.clif_type(place.layout().ty).unwrap();
252 .stack_load(ty, stack_slot, i32::try_from(offset.bytes()).unwrap());
253 place.write_cvalue(fx, CValue::by_val(value, place.layout()));
257 fn expect_reg(reg_or_class: InlineAsmRegOrRegClass) -> InlineAsmReg {
259 InlineAsmRegOrRegClass::Reg(reg) => reg,
260 InlineAsmRegOrRegClass::RegClass(class) => unimplemented!("{:?}", class),
264 fn save_register(generated_asm: &mut String, arch: InlineAsmArch, reg: InlineAsmReg, offset: Size) {
266 InlineAsmArch::X86_64 => {
267 write!(generated_asm, " mov [rbp+0x{:x}], ", offset.bytes()).unwrap();
268 reg.emit(generated_asm, InlineAsmArch::X86_64, None)
270 generated_asm.push('\n');
272 _ => unimplemented!("save_register for {:?}", arch),
277 generated_asm: &mut String,
283 InlineAsmArch::X86_64 => {
284 generated_asm.push_str(" mov ");
285 reg.emit(generated_asm, InlineAsmArch::X86_64, None)
287 writeln!(generated_asm, ", [rbp+0x{:x}]", offset.bytes()).unwrap();
289 _ => unimplemented!("restore_register for {:?}", arch),