2025-05-06 10:00:22 +00:00

284 lines
14 KiB
Rust

//! Lowering of inline assembly.
use hir_expand::name::Name;
use intern::Symbol;
use rustc_hash::{FxHashMap, FxHashSet};
use syntax::{
AstNode, AstPtr, AstToken, T,
ast::{self, HasName, IsString},
};
use tt::TextRange;
use crate::{
expr_store::lower::{ExprCollector, FxIndexSet},
hir::{AsmOperand, AsmOptions, Expr, ExprId, InlineAsm, InlineAsmRegOrRegClass},
};
impl ExprCollector<'_> {
pub(super) fn lower_inline_asm(
&mut self,
asm: ast::AsmExpr,
syntax_ptr: AstPtr<ast::Expr>,
) -> ExprId {
let mut clobber_abis = FxIndexSet::default();
let mut operands = vec![];
let mut options = AsmOptions::empty();
let mut named_pos: FxHashMap<usize, Symbol> = Default::default();
let mut named_args: FxHashMap<Symbol, usize> = Default::default();
let mut reg_args: FxHashSet<usize> = Default::default();
for piece in asm.asm_pieces() {
let slot = operands.len();
let mut lower_reg = |reg: Option<ast::AsmRegSpec>| {
let reg = reg?;
if let Some(string) = reg.string_token() {
reg_args.insert(slot);
Some(InlineAsmRegOrRegClass::Reg(Symbol::intern(string.text())))
} else {
reg.name_ref().map(|name_ref| {
InlineAsmRegOrRegClass::RegClass(Symbol::intern(&name_ref.text()))
})
}
};
let op = match piece {
ast::AsmPiece::AsmClobberAbi(clobber_abi) => {
if let Some(abi_name) = clobber_abi.string_token() {
clobber_abis.insert(Symbol::intern(abi_name.text()));
}
continue;
}
ast::AsmPiece::AsmOptions(opt) => {
opt.asm_options().for_each(|opt| {
options |= match opt.syntax().first_token().map_or(T![$], |it| it.kind()) {
T![att_syntax] => AsmOptions::ATT_SYNTAX,
T![may_unwind] => AsmOptions::MAY_UNWIND,
T![nomem] => AsmOptions::NOMEM,
T![noreturn] => AsmOptions::NORETURN,
T![nostack] => AsmOptions::NOSTACK,
T![preserves_flags] => AsmOptions::PRESERVES_FLAGS,
T![pure] => AsmOptions::PURE,
T![raw] => AsmOptions::RAW,
T![readonly] => AsmOptions::READONLY,
_ => return,
}
});
continue;
}
ast::AsmPiece::AsmOperandNamed(op) => {
let name = op.name().map(|name| Symbol::intern(&name.text()));
if let Some(name) = &name {
named_args.insert(name.clone(), slot);
named_pos.insert(slot, name.clone());
}
let Some(op) = op.asm_operand() else { continue };
(
name.map(Name::new_symbol_root),
match op {
ast::AsmOperand::AsmRegOperand(op) => {
let Some(dir_spec) = op.asm_dir_spec() else {
continue;
};
let Some(reg) = lower_reg(op.asm_reg_spec()) else {
continue;
};
if dir_spec.in_token().is_some() {
let expr = self.collect_expr_opt(
op.asm_operand_expr().and_then(|it| it.in_expr()),
);
AsmOperand::In { reg, expr }
} else if dir_spec.out_token().is_some() {
let expr = op
.asm_operand_expr()
.and_then(|it| it.in_expr())
.filter(|it| !matches!(it, ast::Expr::UnderscoreExpr(_)))
.map(|expr| self.collect_expr(expr));
AsmOperand::Out { reg, expr, late: false }
} else if dir_spec.lateout_token().is_some() {
let expr = op
.asm_operand_expr()
.and_then(|it| it.in_expr())
.filter(|it| !matches!(it, ast::Expr::UnderscoreExpr(_)))
.map(|expr| self.collect_expr(expr));
AsmOperand::Out { reg, expr, late: true }
} else if dir_spec.inout_token().is_some() {
let Some(op_expr) = op.asm_operand_expr() else { continue };
let in_expr = self.collect_expr_opt(op_expr.in_expr());
match op_expr.fat_arrow_token().is_some() {
true => {
let out_expr = op_expr
.out_expr()
.filter(|it| {
!matches!(it, ast::Expr::UnderscoreExpr(_))
})
.map(|expr| self.collect_expr(expr));
AsmOperand::SplitInOut {
reg,
in_expr,
out_expr,
late: false,
}
}
false => {
AsmOperand::InOut { reg, expr: in_expr, late: false }
}
}
} else if dir_spec.inlateout_token().is_some() {
let Some(op_expr) = op.asm_operand_expr() else { continue };
let in_expr = self.collect_expr_opt(op_expr.in_expr());
match op_expr.fat_arrow_token().is_some() {
true => {
let out_expr = op_expr
.out_expr()
.filter(|it| {
!matches!(it, ast::Expr::UnderscoreExpr(_))
})
.map(|expr| self.collect_expr(expr));
AsmOperand::SplitInOut {
reg,
in_expr,
out_expr,
late: true,
}
}
false => {
AsmOperand::InOut { reg, expr: in_expr, late: true }
}
}
} else {
continue;
}
}
ast::AsmOperand::AsmLabel(l) => {
AsmOperand::Label(self.collect_block_opt(l.block_expr()))
}
ast::AsmOperand::AsmConst(c) => {
AsmOperand::Const(self.collect_expr_opt(c.expr()))
}
ast::AsmOperand::AsmSym(s) => {
let Some(path) = s.path().and_then(|p| {
self.lower_path(
p,
&mut ExprCollector::impl_trait_error_allocator,
)
}) else {
continue;
};
AsmOperand::Sym(path)
}
},
)
}
};
operands.push(op);
}
let mut mappings = vec![];
let mut curarg = 0;
if !options.contains(AsmOptions::RAW) {
// Don't treat raw asm as a format string.
asm.template()
.enumerate()
.filter_map(|(idx, it)| Some((idx, it.clone(), self.expand_macros_to_string(it)?)))
.for_each(|(idx, expr, (s, is_direct_literal))| {
mappings.resize_with(idx + 1, Vec::default);
let Ok(text) = s.value() else {
return;
};
let mappings = &mut mappings[idx];
let template_snippet = match expr {
ast::Expr::Literal(literal) => match literal.kind() {
ast::LiteralKind::String(s) => Some(s.text().to_owned()),
_ => None,
},
_ => None,
};
let str_style = match s.quote_offsets() {
Some(offsets) => {
let raw = usize::from(offsets.quotes.0.len()) - 1;
// subtract 1 for the `r` prefix
(raw != 0).then(|| raw - 1)
}
None => None,
};
let mut parser = rustc_parse_format::Parser::new(
&text,
str_style,
template_snippet,
false,
rustc_parse_format::ParseMode::InlineAsm,
);
parser.curarg = curarg;
let mut unverified_pieces = Vec::new();
while let Some(piece) = parser.next() {
if !parser.errors.is_empty() {
break;
} else {
unverified_pieces.push(piece);
}
}
curarg = parser.curarg;
let to_span = |inner_span: std::ops::Range<usize>| {
is_direct_literal.then(|| {
TextRange::new(
inner_span.start.try_into().unwrap(),
inner_span.end.try_into().unwrap(),
)
})
};
for piece in unverified_pieces {
match piece {
rustc_parse_format::Piece::Lit(_) => {}
rustc_parse_format::Piece::NextArgument(arg) => {
// let span = arg_spans.next();
let (operand_idx, _name) = match arg.position {
rustc_parse_format::ArgumentIs(idx)
| rustc_parse_format::ArgumentImplicitlyIs(idx) => {
if idx >= operands.len()
|| named_pos.contains_key(&idx)
|| reg_args.contains(&idx)
{
(None, None)
} else {
(Some(idx), None)
}
}
rustc_parse_format::ArgumentNamed(name) => {
let name = Symbol::intern(name);
(
named_args.get(&name).copied(),
Some(Name::new_symbol_root(name)),
)
}
};
if let Some(operand_idx) = operand_idx {
if let Some(position_span) = to_span(arg.position_span) {
mappings.push((position_span, operand_idx));
}
}
}
}
}
})
};
let idx = self.alloc_expr(
Expr::InlineAsm(InlineAsm { operands: operands.into_boxed_slice(), options }),
syntax_ptr,
);
self.source_map
.template_map
.get_or_insert_with(Default::default)
.asm_to_captures
.insert(idx, mappings);
idx
}
}