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Auto merge of #94468 - Amanieu:global_asm_sym, r=nagisa

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Implement sym operands for global_asm!

Tracking issue: #93333

This PR is pretty much a complete rewrite of `sym` operand support for inline assembly so that the same implementation can be shared by `asm!` and `global_asm!`. The main changes are:
- At the AST level, `sym` is represented as a special `InlineAsmSym` AST node containing a path instead of an `Expr`.
- At the HIR level, `sym` is split into `SymStatic` and `SymFn` depending on whether the path resolves to a static during AST lowering (defaults to `SynFn` if `get_early_res` fails).
  - `SymFn` is just an `AnonConst`. It runs through typeck and we just collect the resulting type at the end. An error is emitted if the type is not a `FnDef`.
  - `SymStatic` directly holds a path and the `DefId` of the `static` that it is pointing to.
- The representation at the MIR level is mostly unchanged. There is a minor change to THIR where `SymFn` is a constant instead of an expression.
- At the codegen level we need to apply the target's symbol mangling to the result of `tcx.symbol_name()` depending on the target. This is done by calling the LLVM name mangler, which handles all of the details.
  - On Mach-O, all symbols have a leading underscore.
  - On x86 Windows, different mangling is used for cdecl, stdcall, fastcall and vectorcall.
  - No mangling is needed on other platforms.

r? `@nagisa`
cc `@eddyb`
This commit is contained in:
bors 2022-04-16 04:46:01 +00:00
commit 080d5452e1
50 changed files with 654 additions and 245 deletions
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22
compiler/rustc_builtin_macros/src/asm.rs
View file

@ -154,17 +154,19 @@ pub fn parse_asm_args<'a>(
} else if p.eat_keyword(kw::Const) {
let anon_const = p.parse_anon_const_expr()?;
ast::InlineAsmOperand::Const { anon_const }
} else if !is_global_asm && p.eat_keyword(sym::sym) {
} else if p.eat_keyword(sym::sym) {
let expr = p.parse_expr()?;
match expr.kind {
ast::ExprKind::Path(..) => {}
_ => {
let err = diag
.struct_span_err(expr.span, "argument to `sym` must be a path expression");
return Err(err);
}
}
ast::InlineAsmOperand::Sym { expr }
let ast::ExprKind::Path(qself, path) = &expr.kind else {
let err = diag
.struct_span_err(expr.span, "expected a path for argument to `sym`");
return Err(err);
};
let sym = ast::InlineAsmSym {
id: ast::DUMMY_NODE_ID,
qself: qself.clone(),
path: path.clone(),
};
ast::InlineAsmOperand::Sym { sym }
} else if allow_templates {
let template = p.parse_expr()?;
// If it can't possibly expand to a string, provide diagnostics here to include other