bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Rollup merge of #119365 - nbdd0121:asm-goto, r=Amanieu

Browse source 
Add asm goto support to `asm!`

Tracking issue: #119364

This PR implements asm-goto support, using the syntax described in "future possibilities" section of [RFC2873](https://rust-lang.github.io/rfcs/2873-inline-asm.html#asm-goto).

Currently I have only implemented the `label` part, not the `fallthrough` part (i.e. fallthrough is implicit). This doesn't reduce the expressive though, since you can use label-break to get arbitrary control flow or simply set a value and rely on jump threading optimisation to get the desired control flow. I can add that later if deemed necessary.

r? ``@Amanieu``
cc ``@ojeda``
This commit is contained in:
Matthias Krüger 2024-03-08 08:19:17 +01:00 • committed by GitHub
commit d774fbea7c
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
76 changed files with 857 additions and 200 deletions
Download patch file Download diff file Expand all files Collapse all files

10
compiler/rustc_builtin_macros/src/asm.rs
View file

@ -164,6 +164,9 @@ pub fn parse_asm_args<'a>(
path: path.clone(),
};
ast::InlineAsmOperand::Sym { sym }
} else if !is_global_asm && p.eat_keyword(sym::label) {
let block = p.parse_block()?;
ast::InlineAsmOperand::Label { block }
} else if allow_templates {
let template = p.parse_expr()?;
// If it can't possibly expand to a string, provide diagnostics here to include other
@ -240,6 +243,7 @@ pub fn parse_asm_args<'a>(
let mut have_real_output = false;
let mut outputs_sp = vec![];
let mut regclass_outputs = vec![];
let mut labels_sp = vec![];
for (op, op_sp) in &args.operands {
match op {
ast::InlineAsmOperand::Out { reg, expr, .. }
@ -257,6 +261,9 @@ pub fn parse_asm_args<'a>(
regclass_outputs.push(*op_sp);
}
}
ast::InlineAsmOperand::Label { .. } => {
labels_sp.push(*op_sp);
}
_ => {}
}
}
@ -268,6 +275,9 @@ pub fn parse_asm_args<'a>(
// Bail out now since this is likely to confuse MIR
return Err(err);
}
if args.options.contains(ast::InlineAsmOptions::MAY_UNWIND) && !labels_sp.is_empty() {
dcx.emit_err(errors::AsmMayUnwind { labels_sp });
}
if args.clobber_abis.len() > 0 {
if is_global_asm {