rust/src/inline_asm.rs

936 lines
36 KiB
Rust

//! Codegen of `asm!` invocations.
use std::fmt::Write;
use cranelift_codegen::isa::CallConv;
use rustc_ast::ast::{InlineAsmOptions, InlineAsmTemplatePiece};
use rustc_hir::LangItem;
use rustc_span::sym;
use rustc_target::asm::*;
use target_lexicon::BinaryFormat;
use crate::prelude::*;
pub(crate) enum CInlineAsmOperand<'tcx> {
In {
reg: InlineAsmRegOrRegClass,
value: Value,
},
Out {
reg: InlineAsmRegOrRegClass,
late: bool,
place: Option<CPlace<'tcx>>,
},
InOut {
reg: InlineAsmRegOrRegClass,
_late: bool,
in_value: Value,
out_place: Option<CPlace<'tcx>>,
},
Const {
value: String,
},
Symbol {
symbol: String,
},
}
pub(crate) fn codegen_inline_asm_terminator<'tcx>(
fx: &mut FunctionCx<'_, '_, 'tcx>,
span: Span,
template: &[InlineAsmTemplatePiece],
operands: &[InlineAsmOperand<'tcx>],
options: InlineAsmOptions,
destination: Option<mir::BasicBlock>,
) {
// Used by panic_abort on Windows, but uses a syntax which only happens to work with
// asm!() by accident and breaks with the GNU assembler as well as global_asm!() for
// the LLVM backend.
if template.len() == 1
&& template[0] == InlineAsmTemplatePiece::String("int $$0x29".to_string())
{
fx.bcx.ins().trap(TrapCode::User(1));
return;
}
let operands = operands
.iter()
.map(|operand| match *operand {
InlineAsmOperand::In { reg, ref value } => CInlineAsmOperand::In {
reg,
value: crate::base::codegen_operand(fx, value).load_scalar(fx),
},
InlineAsmOperand::Out { reg, late, ref place } => CInlineAsmOperand::Out {
reg,
late,
place: place.map(|place| crate::base::codegen_place(fx, place)),
},
InlineAsmOperand::InOut { reg, late, ref in_value, ref out_place } => {
CInlineAsmOperand::InOut {
reg,
_late: late,
in_value: crate::base::codegen_operand(fx, in_value).load_scalar(fx),
out_place: out_place.map(|place| crate::base::codegen_place(fx, place)),
}
}
InlineAsmOperand::Const { ref value } => {
let (const_value, ty) = crate::constant::eval_mir_constant(fx, value);
let value = rustc_codegen_ssa::common::asm_const_to_str(
fx.tcx,
span,
const_value,
fx.layout_of(ty),
);
CInlineAsmOperand::Const { value }
}
InlineAsmOperand::SymFn { ref value } => {
if cfg!(not(feature = "inline_asm_sym")) {
fx.tcx
.dcx()
.span_err(span, "asm! and global_asm! sym operands are not yet supported");
}
let const_ = fx.monomorphize(value.const_);
if let ty::FnDef(def_id, args) = *const_.ty().kind() {
let instance = ty::Instance::resolve_for_fn_ptr(
fx.tcx,
ty::ParamEnv::reveal_all(),
def_id,
args,
)
.unwrap();
let symbol = fx.tcx.symbol_name(instance);
// Pass a wrapper rather than the function itself as the function itself may not
// be exported from the main codegen unit and may thus be unreachable from the
// object file created by an external assembler.
let inline_asm_index = fx.cx.inline_asm_index.get();
fx.cx.inline_asm_index.set(inline_asm_index + 1);
let wrapper_name = format!(
"__inline_asm_{}_wrapper_n{}",
fx.cx.cgu_name.as_str().replace('.', "__").replace('-', "_"),
inline_asm_index
);
let sig =
get_function_sig(fx.tcx, fx.target_config.default_call_conv, instance);
create_wrapper_function(fx.module, sig, &wrapper_name, symbol.name);
CInlineAsmOperand::Symbol { symbol: wrapper_name }
} else {
span_bug!(span, "invalid type for asm sym (fn)");
}
}
InlineAsmOperand::SymStatic { def_id } => {
assert!(fx.tcx.is_static(def_id));
let instance = Instance::mono(fx.tcx, def_id);
CInlineAsmOperand::Symbol { symbol: fx.tcx.symbol_name(instance).name.to_owned() }
}
InlineAsmOperand::Label { .. } => {
span_bug!(span, "asm! label operands are not yet supported");
}
})
.collect::<Vec<_>>();
codegen_inline_asm_inner(fx, template, &operands, options);
match destination {
Some(destination) => {
let destination_block = fx.get_block(destination);
fx.bcx.ins().jump(destination_block, &[]);
}
None => {
fx.bcx.ins().trap(TrapCode::UnreachableCodeReached);
}
}
}
pub(crate) fn codegen_inline_asm_inner<'tcx>(
fx: &mut FunctionCx<'_, '_, 'tcx>,
template: &[InlineAsmTemplatePiece],
operands: &[CInlineAsmOperand<'tcx>],
options: InlineAsmOptions,
) {
// FIXME add .eh_frame unwind info directives
let mut asm_gen = InlineAssemblyGenerator {
tcx: fx.tcx,
arch: fx.tcx.sess.asm_arch.unwrap(),
enclosing_def_id: fx.instance.def_id(),
template,
operands,
options,
registers: Vec::new(),
stack_slots_clobber: Vec::new(),
stack_slots_input: Vec::new(),
stack_slots_output: Vec::new(),
stack_slot_size: Size::from_bytes(0),
is_naked: false,
};
asm_gen.allocate_registers();
asm_gen.allocate_stack_slots();
let inline_asm_index = fx.cx.inline_asm_index.get();
fx.cx.inline_asm_index.set(inline_asm_index + 1);
let asm_name = format!(
"__inline_asm_{}_n{}",
fx.cx.cgu_name.as_str().replace('.', "__").replace('-', "_"),
inline_asm_index
);
let generated_asm = asm_gen.generate_asm_wrapper(&asm_name);
fx.cx.global_asm.push_str(&generated_asm);
let mut inputs = Vec::new();
let mut outputs = Vec::new();
for (i, operand) in operands.iter().enumerate() {
match operand {
CInlineAsmOperand::In { reg: _, value } => {
inputs.push((asm_gen.stack_slots_input[i].unwrap(), *value));
}
CInlineAsmOperand::Out { reg: _, late: _, place } => {
if let Some(place) = place {
outputs.push((asm_gen.stack_slots_output[i].unwrap(), *place));
}
}
CInlineAsmOperand::InOut { reg: _, _late: _, in_value, out_place } => {
inputs.push((asm_gen.stack_slots_input[i].unwrap(), *in_value));
if let Some(out_place) = out_place {
outputs.push((asm_gen.stack_slots_output[i].unwrap(), *out_place));
}
}
CInlineAsmOperand::Const { value: _ } | CInlineAsmOperand::Symbol { symbol: _ } => {}
}
}
call_inline_asm(fx, &asm_name, asm_gen.stack_slot_size, inputs, outputs);
}
pub(crate) fn codegen_naked_asm<'tcx>(
tcx: TyCtxt<'tcx>,
cx: &mut crate::CodegenCx,
module: &mut dyn Module,
instance: Instance<'tcx>,
span: Span,
symbol_name: &str,
template: &[InlineAsmTemplatePiece],
operands: &[InlineAsmOperand<'tcx>],
options: InlineAsmOptions,
) {
// FIXME add .eh_frame unwind info directives
let operands = operands
.iter()
.map(|operand| match *operand {
InlineAsmOperand::In { .. }
| InlineAsmOperand::Out { .. }
| InlineAsmOperand::InOut { .. } => {
span_bug!(span, "invalid operand type for naked asm")
}
InlineAsmOperand::Const { ref value } => {
let cv = instance.instantiate_mir_and_normalize_erasing_regions(
tcx,
ty::ParamEnv::reveal_all(),
ty::EarlyBinder::bind(value.const_),
);
let const_value = cv
.eval(tcx, ty::ParamEnv::reveal_all(), value.span)
.expect("erroneous constant missed by mono item collection");
let value = rustc_codegen_ssa::common::asm_const_to_str(
tcx,
span,
const_value,
RevealAllLayoutCx(tcx).layout_of(cv.ty()),
);
CInlineAsmOperand::Const { value }
}
InlineAsmOperand::SymFn { ref value } => {
if cfg!(not(feature = "inline_asm_sym")) {
tcx.dcx()
.span_err(span, "asm! and global_asm! sym operands are not yet supported");
}
let const_ = instance.instantiate_mir_and_normalize_erasing_regions(
tcx,
ty::ParamEnv::reveal_all(),
ty::EarlyBinder::bind(value.const_),
);
if let ty::FnDef(def_id, args) = *const_.ty().kind() {
let instance = ty::Instance::resolve_for_fn_ptr(
tcx,
ty::ParamEnv::reveal_all(),
def_id,
args,
)
.unwrap();
let symbol = tcx.symbol_name(instance);
// Pass a wrapper rather than the function itself as the function itself may not
// be exported from the main codegen unit and may thus be unreachable from the
// object file created by an external assembler.
let inline_asm_index = cx.inline_asm_index.get();
cx.inline_asm_index.set(inline_asm_index + 1);
let wrapper_name = format!(
"__inline_asm_{}_wrapper_n{}",
cx.cgu_name.as_str().replace('.', "__").replace('-', "_"),
inline_asm_index
);
let sig =
get_function_sig(tcx, module.target_config().default_call_conv, instance);
create_wrapper_function(module, sig, &wrapper_name, symbol.name);
CInlineAsmOperand::Symbol { symbol: wrapper_name }
} else {
span_bug!(span, "invalid type for asm sym (fn)");
}
}
InlineAsmOperand::SymStatic { def_id } => {
assert!(tcx.is_static(def_id));
let instance = Instance::mono(tcx, def_id);
CInlineAsmOperand::Symbol { symbol: tcx.symbol_name(instance).name.to_owned() }
}
InlineAsmOperand::Label { .. } => {
span_bug!(span, "asm! label operands are not yet supported");
}
})
.collect::<Vec<_>>();
let asm_gen = InlineAssemblyGenerator {
tcx,
arch: tcx.sess.asm_arch.unwrap(),
enclosing_def_id: instance.def_id(),
template,
operands: &operands,
options,
registers: Vec::new(),
stack_slots_clobber: Vec::new(),
stack_slots_input: Vec::new(),
stack_slots_output: Vec::new(),
stack_slot_size: Size::from_bytes(0),
is_naked: true,
};
let generated_asm = asm_gen.generate_asm_wrapper(symbol_name);
cx.global_asm.push_str(&generated_asm);
}
struct InlineAssemblyGenerator<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
arch: InlineAsmArch,
enclosing_def_id: DefId,
template: &'a [InlineAsmTemplatePiece],
operands: &'a [CInlineAsmOperand<'tcx>],
options: InlineAsmOptions,
registers: Vec<Option<InlineAsmReg>>,
stack_slots_clobber: Vec<Option<Size>>,
stack_slots_input: Vec<Option<Size>>,
stack_slots_output: Vec<Option<Size>>,
stack_slot_size: Size,
is_naked: bool,
}
impl<'tcx> InlineAssemblyGenerator<'_, 'tcx> {
fn allocate_registers(&mut self) {
assert!(!self.is_naked);
let sess = self.tcx.sess;
let map = allocatable_registers(
self.arch,
sess.relocation_model(),
self.tcx.asm_target_features(self.enclosing_def_id),
&sess.target,
);
let mut allocated = FxHashMap::<_, (bool, bool)>::default();
let mut regs = vec![None; self.operands.len()];
// Add explicit registers to the allocated set.
for (i, operand) in self.operands.iter().enumerate() {
match *operand {
CInlineAsmOperand::In { reg: InlineAsmRegOrRegClass::Reg(reg), .. } => {
regs[i] = Some(reg);
allocated.entry(reg).or_default().0 = true;
}
CInlineAsmOperand::Out {
reg: InlineAsmRegOrRegClass::Reg(reg),
late: true,
..
} => {
regs[i] = Some(reg);
allocated.entry(reg).or_default().1 = true;
}
CInlineAsmOperand::Out { reg: InlineAsmRegOrRegClass::Reg(reg), .. }
| CInlineAsmOperand::InOut { reg: InlineAsmRegOrRegClass::Reg(reg), .. } => {
regs[i] = Some(reg);
allocated.insert(reg, (true, true));
}
_ => (),
}
}
// Allocate out/inout/inlateout registers first because they are more constrained.
for (i, operand) in self.operands.iter().enumerate() {
match *operand {
CInlineAsmOperand::Out {
reg: InlineAsmRegOrRegClass::RegClass(class),
late: false,
..
}
| CInlineAsmOperand::InOut {
reg: InlineAsmRegOrRegClass::RegClass(class), ..
} => {
let mut alloc_reg = None;
for &reg in &map[&class] {
let mut used = false;
reg.overlapping_regs(|r| {
if allocated.contains_key(&r) {
used = true;
}
});
if !used {
alloc_reg = Some(reg);
break;
}
}
let reg = alloc_reg.expect("cannot allocate registers");
regs[i] = Some(reg);
allocated.insert(reg, (true, true));
}
_ => (),
}
}
// Allocate in/lateout.
for (i, operand) in self.operands.iter().enumerate() {
match *operand {
CInlineAsmOperand::In { reg: InlineAsmRegOrRegClass::RegClass(class), .. } => {
let mut alloc_reg = None;
for &reg in &map[&class] {
let mut used = false;
reg.overlapping_regs(|r| {
if allocated.get(&r).copied().unwrap_or_default().0 {
used = true;
}
});
if !used {
alloc_reg = Some(reg);
break;
}
}
let reg = alloc_reg.expect("cannot allocate registers");
regs[i] = Some(reg);
allocated.entry(reg).or_default().0 = true;
}
CInlineAsmOperand::Out {
reg: InlineAsmRegOrRegClass::RegClass(class),
late: true,
..
} => {
let mut alloc_reg = None;
for &reg in &map[&class] {
let mut used = false;
reg.overlapping_regs(|r| {
if allocated.get(&r).copied().unwrap_or_default().1 {
used = true;
}
});
if !used {
alloc_reg = Some(reg);
break;
}
}
let reg = alloc_reg.expect("cannot allocate registers");
regs[i] = Some(reg);
allocated.entry(reg).or_default().1 = true;
}
_ => (),
}
}
self.registers = regs;
}
fn allocate_stack_slots(&mut self) {
assert!(!self.is_naked);
let mut slot_size = Size::from_bytes(0);
let mut slots_clobber = vec![None; self.operands.len()];
let mut slots_input = vec![None; self.operands.len()];
let mut slots_output = vec![None; self.operands.len()];
let new_slot_fn = |slot_size: &mut Size, reg_class: InlineAsmRegClass| {
let reg_size =
reg_class.supported_types(self.arch).iter().map(|(ty, _)| ty.size()).max().unwrap();
let align = rustc_target::abi::Align::from_bytes(reg_size.bytes()).unwrap();
let offset = slot_size.align_to(align);
*slot_size = offset + reg_size;
offset
};
let mut new_slot = |x| new_slot_fn(&mut slot_size, x);
// Allocate stack slots for saving clobbered registers
let abi_clobber = InlineAsmClobberAbi::parse(self.arch, &self.tcx.sess.target, sym::C)
.unwrap()
.clobbered_regs();
for (i, reg) in self.registers.iter().enumerate().filter_map(|(i, r)| r.map(|r| (i, r))) {
let mut need_save = true;
// If the register overlaps with a register clobbered by function call, then
// we don't need to save it.
for r in abi_clobber {
r.overlapping_regs(|r| {
if r == reg {
need_save = false;
}
});
if !need_save {
break;
}
}
if need_save {
slots_clobber[i] = Some(new_slot(reg.reg_class()));
}
}
// Allocate stack slots for inout
for (i, operand) in self.operands.iter().enumerate() {
match *operand {
CInlineAsmOperand::InOut { reg, out_place: Some(_), .. } => {
let slot = new_slot(reg.reg_class());
slots_input[i] = Some(slot);
slots_output[i] = Some(slot);
}
_ => (),
}
}
let slot_size_before_input = slot_size;
let mut new_slot = |x| new_slot_fn(&mut slot_size, x);
// Allocate stack slots for input
for (i, operand) in self.operands.iter().enumerate() {
match *operand {
CInlineAsmOperand::In { reg, .. }
| CInlineAsmOperand::InOut { reg, out_place: None, .. } => {
slots_input[i] = Some(new_slot(reg.reg_class()));
}
_ => (),
}
}
// Reset slot size to before input so that input and output operands can overlap
// and save some memory.
let slot_size_after_input = slot_size;
slot_size = slot_size_before_input;
let mut new_slot = |x| new_slot_fn(&mut slot_size, x);
// Allocate stack slots for output
for (i, operand) in self.operands.iter().enumerate() {
match *operand {
CInlineAsmOperand::Out { reg, place: Some(_), .. } => {
slots_output[i] = Some(new_slot(reg.reg_class()));
}
_ => (),
}
}
slot_size = slot_size.max(slot_size_after_input);
self.stack_slots_clobber = slots_clobber;
self.stack_slots_input = slots_input;
self.stack_slots_output = slots_output;
self.stack_slot_size = slot_size;
}
fn generate_asm_wrapper(&self, asm_name: &str) -> String {
let binary_format = crate::target_triple(self.tcx.sess).binary_format;
let mut generated_asm = String::new();
match binary_format {
BinaryFormat::Elf => {
writeln!(generated_asm, ".globl {}", asm_name).unwrap();
writeln!(generated_asm, ".type {},@function", asm_name).unwrap();
writeln!(generated_asm, ".section .text.{},\"ax\",@progbits", asm_name).unwrap();
writeln!(generated_asm, "{}:", asm_name).unwrap();
}
BinaryFormat::Macho => {
writeln!(generated_asm, ".globl _{}", asm_name).unwrap();
writeln!(generated_asm, "_{}:", asm_name).unwrap();
}
BinaryFormat::Coff => {
writeln!(generated_asm, ".globl {}", asm_name).unwrap();
writeln!(generated_asm, "{}:", asm_name).unwrap();
}
_ => self
.tcx
.dcx()
.fatal(format!("Unsupported binary format for inline asm: {binary_format:?}")),
}
let is_x86 = matches!(self.arch, InlineAsmArch::X86 | InlineAsmArch::X86_64);
if is_x86 {
generated_asm.push_str(".intel_syntax noprefix\n");
}
if !self.is_naked {
Self::prologue(&mut generated_asm, self.arch);
// Save clobbered registers
if !self.options.contains(InlineAsmOptions::NORETURN) {
for (reg, slot) in self
.registers
.iter()
.zip(self.stack_slots_clobber.iter().copied())
.filter_map(|(r, s)| r.zip(s))
{
Self::save_register(&mut generated_asm, self.arch, reg, slot);
}
}
// Write input registers
for (reg, slot) in self
.registers
.iter()
.zip(self.stack_slots_input.iter().copied())
.filter_map(|(r, s)| r.zip(s))
{
Self::restore_register(&mut generated_asm, self.arch, reg, slot);
}
}
if is_x86 && self.options.contains(InlineAsmOptions::ATT_SYNTAX) {
generated_asm.push_str(".att_syntax\n");
}
// The actual inline asm
for piece in self.template {
match piece {
InlineAsmTemplatePiece::String(s) => {
generated_asm.push_str(s);
}
InlineAsmTemplatePiece::Placeholder { operand_idx, modifier, span: _ } => {
match self.operands[*operand_idx] {
CInlineAsmOperand::In { .. }
| CInlineAsmOperand::Out { .. }
| CInlineAsmOperand::InOut { .. } => {
if self.options.contains(InlineAsmOptions::ATT_SYNTAX) {
generated_asm.push('%');
}
let reg = self.registers[*operand_idx].unwrap();
match self.arch {
InlineAsmArch::X86_64 => match reg {
InlineAsmReg::X86(reg)
if reg as u32 >= X86InlineAsmReg::xmm0 as u32
&& reg as u32 <= X86InlineAsmReg::xmm15 as u32 =>
{
// rustc emits x0 rather than xmm0
let class = match *modifier {
None | Some('x') => "xmm",
Some('y') => "ymm",
Some('z') => "zmm",
_ => unreachable!(),
};
write!(
generated_asm,
"{class}{}",
reg as u32 - X86InlineAsmReg::xmm0 as u32
)
.unwrap();
}
_ => reg
.emit(&mut generated_asm, InlineAsmArch::X86_64, *modifier)
.unwrap(),
},
_ => reg.emit(&mut generated_asm, self.arch, *modifier).unwrap(),
}
}
CInlineAsmOperand::Const { ref value } => {
generated_asm.push_str(value);
}
CInlineAsmOperand::Symbol { ref symbol } => generated_asm.push_str(symbol),
}
}
}
}
generated_asm.push('\n');
if is_x86 && self.options.contains(InlineAsmOptions::ATT_SYNTAX) {
generated_asm.push_str(".intel_syntax noprefix\n");
}
if !self.is_naked {
if !self.options.contains(InlineAsmOptions::NORETURN) {
// Read output registers
for (reg, slot) in self
.registers
.iter()
.zip(self.stack_slots_output.iter().copied())
.filter_map(|(r, s)| r.zip(s))
{
Self::save_register(&mut generated_asm, self.arch, reg, slot);
}
// Restore clobbered registers
for (reg, slot) in self
.registers
.iter()
.zip(self.stack_slots_clobber.iter().copied())
.filter_map(|(r, s)| r.zip(s))
{
Self::restore_register(&mut generated_asm, self.arch, reg, slot);
}
Self::epilogue(&mut generated_asm, self.arch);
} else {
Self::epilogue_noreturn(&mut generated_asm, self.arch);
}
}
if is_x86 {
generated_asm.push_str(".att_syntax\n");
}
match binary_format {
BinaryFormat::Elf => {
writeln!(generated_asm, ".size {name}, .-{name}", name = asm_name).unwrap();
generated_asm.push_str(".text\n");
}
BinaryFormat::Macho | BinaryFormat::Coff => {}
_ => self
.tcx
.dcx()
.fatal(format!("Unsupported binary format for inline asm: {binary_format:?}")),
}
generated_asm.push_str("\n\n");
generated_asm
}
fn prologue(generated_asm: &mut String, arch: InlineAsmArch) {
match arch {
InlineAsmArch::X86_64 => {
generated_asm.push_str(" push rbp\n");
generated_asm.push_str(" mov rbp,rsp\n");
generated_asm.push_str(" push rbx\n"); // rbx is callee saved
// rbx is reserved by LLVM for the "base pointer", so rustc doesn't allow using it
generated_asm.push_str(" mov rbx,rdi\n");
}
InlineAsmArch::AArch64 => {
generated_asm.push_str(" stp fp, lr, [sp, #-32]!\n");
generated_asm.push_str(" mov fp, sp\n");
generated_asm.push_str(" str x19, [sp, #24]\n"); // x19 is callee saved
// x19 is reserved by LLVM for the "base pointer", so rustc doesn't allow using it
generated_asm.push_str(" mov x19, x0\n");
}
InlineAsmArch::RiscV64 => {
generated_asm.push_str(" addi sp, sp, -16\n");
generated_asm.push_str(" sd ra, 8(sp)\n");
generated_asm.push_str(" sd s1, 0(sp)\n"); // s1 is callee saved
// s1/x9 is reserved by LLVM for the "base pointer", so rustc doesn't allow using it
generated_asm.push_str(" mv s1, a0\n");
}
_ => unimplemented!("prologue for {:?}", arch),
}
}
fn epilogue(generated_asm: &mut String, arch: InlineAsmArch) {
match arch {
InlineAsmArch::X86_64 => {
generated_asm.push_str(" pop rbx\n");
generated_asm.push_str(" pop rbp\n");
generated_asm.push_str(" ret\n");
}
InlineAsmArch::AArch64 => {
generated_asm.push_str(" ldr x19, [sp, #24]\n");
generated_asm.push_str(" ldp fp, lr, [sp], #32\n");
generated_asm.push_str(" ret\n");
}
InlineAsmArch::RiscV64 => {
generated_asm.push_str(" ld s1, 0(sp)\n");
generated_asm.push_str(" ld ra, 8(sp)\n");
generated_asm.push_str(" addi sp, sp, 16\n");
generated_asm.push_str(" ret\n");
}
_ => unimplemented!("epilogue for {:?}", arch),
}
}
fn epilogue_noreturn(generated_asm: &mut String, arch: InlineAsmArch) {
match arch {
InlineAsmArch::X86_64 => {
generated_asm.push_str(" ud2\n");
}
InlineAsmArch::AArch64 => {
generated_asm.push_str(" brk #0x1\n");
}
InlineAsmArch::RiscV64 => {
generated_asm.push_str(" ebreak\n");
}
_ => unimplemented!("epilogue_noreturn for {:?}", arch),
}
}
fn save_register(
generated_asm: &mut String,
arch: InlineAsmArch,
reg: InlineAsmReg,
offset: Size,
) {
match arch {
InlineAsmArch::X86_64 => {
match reg {
InlineAsmReg::X86(reg)
if reg as u32 >= X86InlineAsmReg::xmm0 as u32
&& reg as u32 <= X86InlineAsmReg::xmm15 as u32 =>
{
// rustc emits x0 rather than xmm0
write!(generated_asm, " movups [rbx+0x{:x}], ", offset.bytes()).unwrap();
write!(generated_asm, "xmm{}", reg as u32 - X86InlineAsmReg::xmm0 as u32)
.unwrap();
}
_ => {
write!(generated_asm, " mov [rbx+0x{:x}], ", offset.bytes()).unwrap();
reg.emit(generated_asm, InlineAsmArch::X86_64, None).unwrap();
}
}
generated_asm.push('\n');
}
InlineAsmArch::AArch64 => {
generated_asm.push_str(" str ");
reg.emit(generated_asm, InlineAsmArch::AArch64, None).unwrap();
writeln!(generated_asm, ", [x19, 0x{:x}]", offset.bytes()).unwrap();
}
InlineAsmArch::RiscV64 => {
generated_asm.push_str(" sd ");
reg.emit(generated_asm, InlineAsmArch::RiscV64, None).unwrap();
writeln!(generated_asm, ", 0x{:x}(s1)", offset.bytes()).unwrap();
}
_ => unimplemented!("save_register for {:?}", arch),
}
}
fn restore_register(
generated_asm: &mut String,
arch: InlineAsmArch,
reg: InlineAsmReg,
offset: Size,
) {
match arch {
InlineAsmArch::X86_64 => {
match reg {
InlineAsmReg::X86(reg)
if reg as u32 >= X86InlineAsmReg::xmm0 as u32
&& reg as u32 <= X86InlineAsmReg::xmm15 as u32 =>
{
// rustc emits x0 rather than xmm0
write!(
generated_asm,
" movups xmm{}",
reg as u32 - X86InlineAsmReg::xmm0 as u32
)
.unwrap();
}
_ => {
generated_asm.push_str(" mov ");
reg.emit(generated_asm, InlineAsmArch::X86_64, None).unwrap()
}
}
writeln!(generated_asm, ", [rbx+0x{:x}]", offset.bytes()).unwrap();
}
InlineAsmArch::AArch64 => {
generated_asm.push_str(" ldr ");
reg.emit(generated_asm, InlineAsmArch::AArch64, None).unwrap();
writeln!(generated_asm, ", [x19, 0x{:x}]", offset.bytes()).unwrap();
}
InlineAsmArch::RiscV64 => {
generated_asm.push_str(" ld ");
reg.emit(generated_asm, InlineAsmArch::RiscV64, None).unwrap();
writeln!(generated_asm, ", 0x{:x}(s1)", offset.bytes()).unwrap();
}
_ => unimplemented!("restore_register for {:?}", arch),
}
}
}
fn call_inline_asm<'tcx>(
fx: &mut FunctionCx<'_, '_, 'tcx>,
asm_name: &str,
slot_size: Size,
inputs: Vec<(Size, Value)>,
outputs: Vec<(Size, CPlace<'tcx>)>,
) {
let stack_slot = fx.create_stack_slot(u32::try_from(slot_size.bytes()).unwrap(), 16);
let inline_asm_func = fx
.module
.declare_function(
asm_name,
Linkage::Import,
&Signature {
call_conv: CallConv::SystemV,
params: vec![AbiParam::new(fx.pointer_type)],
returns: vec![],
},
)
.unwrap();
let inline_asm_func = fx.module.declare_func_in_func(inline_asm_func, fx.bcx.func);
if fx.clif_comments.enabled() {
fx.add_comment(inline_asm_func, asm_name);
}
for (offset, value) in inputs {
stack_slot.offset(fx, i32::try_from(offset.bytes()).unwrap().into()).store(
fx,
value,
MemFlags::trusted(),
);
}
let stack_slot_addr = stack_slot.get_addr(fx);
fx.bcx.ins().call(inline_asm_func, &[stack_slot_addr]);
for (offset, place) in outputs {
let ty = if place.layout().ty.is_simd() {
let (lane_count, lane_type) = place.layout().ty.simd_size_and_type(fx.tcx);
asm_clif_type(fx, lane_type).unwrap().by(lane_count.try_into().unwrap()).unwrap()
} else {
asm_clif_type(fx, place.layout().ty).unwrap()
};
let value = stack_slot.offset(fx, i32::try_from(offset.bytes()).unwrap().into()).load(
fx,
ty,
MemFlags::trusted(),
);
place.write_cvalue(fx, CValue::by_val(value, place.layout()));
}
}
fn asm_clif_type<'tcx>(fx: &FunctionCx<'_, '_, 'tcx>, ty: Ty<'tcx>) -> Option<types::Type> {
match ty.kind() {
// Adapted from https://github.com/rust-lang/rust/blob/f3c66088610c1b80110297c2d9a8b5f9265b013f/compiler/rustc_hir_analysis/src/check/intrinsicck.rs#L136-L151
ty::Adt(adt, args) if fx.tcx.is_lang_item(adt.did(), LangItem::MaybeUninit) => {
let fields = &adt.non_enum_variant().fields;
let ty = fields[FieldIdx::from_u32(1)].ty(fx.tcx, args);
let ty::Adt(ty, args) = ty.kind() else {
unreachable!("expected first field of `MaybeUninit` to be an ADT")
};
assert!(
ty.is_manually_drop(),
"expected first field of `MaybeUninit` to be `ManuallyDrop`"
);
let fields = &ty.non_enum_variant().fields;
let ty = fields[FieldIdx::ZERO].ty(fx.tcx, args);
fx.clif_type(ty)
}
_ => fx.clif_type(ty),
}
}