feat: support parsing asm! args

Author: calebcartwright

Diff for: src/lib.rs

@@ -15,6 +15,7 @@ extern crate log;
 // N.B. these crates are loaded from the sysroot, so they need extern crate.
 extern crate rustc_ast;
 extern crate rustc_ast_pretty;
+extern crate rustc_builtin_macros;
 extern crate rustc_data_structures;
 extern crate rustc_errors;
 extern crate rustc_expand;

Diff for: src/parse/macros/asm.rs

@@ -0,0 +1,11 @@
+use rustc_ast::ast;
+use rustc_builtin_macros::asm::{parse_asm_args, AsmArgs};
+
+use crate::rewrite::RewriteContext;
+
+#[allow(dead_code)]
+pub(crate) fn parse_asm(context: &RewriteContext<'_>, mac: &ast::MacCall) -> Option<AsmArgs> {
+    let ts = mac.args.inner_tokens();
+    let mut parser = super::build_parser(context, ts);
+    parse_asm_args(&mut parser, context.parse_sess.inner(), mac.span(), false).ok()
+}

Diff for: src/parse/macros/mod.rs

@@ -10,6 +10,7 @@ use rustc_span::Symbol;
 use crate::macros::MacroArg;
 use crate::rewrite::RewriteContext;
 
+pub(crate) mod asm;
 pub(crate) mod cfg_if;
 pub(crate) mod lazy_static;