diff --git a/src/libsyntax/config.rs b/src/libsyntax/config.rs index eb845e463a0f1..7ca0591be5064 100644 --- a/src/libsyntax/config.rs +++ b/src/libsyntax/config.rs @@ -12,7 +12,7 @@ use attr::AttrMetaMethods; use diagnostic::SpanHandler; use fold::Folder; use {ast, fold, attr}; -use codemap::Spanned; +use codemap::{Spanned, respan}; use ptr::P; use util::small_vector::SmallVector; @@ -26,6 +26,7 @@ struct Context where F: FnMut(&[ast::Attribute]) -> bool { // Support conditional compilation by transforming the AST, stripping out // any items that do not belong in the current configuration pub fn strip_unconfigured_items(diagnostic: &SpanHandler, krate: ast::Crate) -> ast::Crate { + let krate = process_cfg_attr(diagnostic, krate); let config = krate.config.clone(); strip_items(krate, |attrs| in_cfg(diagnostic, &config, attrs)) } @@ -281,3 +282,49 @@ fn in_cfg(diagnostic: &SpanHandler, cfg: &[P], attrs: &[ast::Attr attr::cfg_matches(diagnostic, cfg, &*mis[0]) }) } + +struct CfgAttrFolder<'a> { + diag: &'a SpanHandler, + config: ast::CrateConfig, +} + +// Process `#[cfg_attr]`. +fn process_cfg_attr(diagnostic: &SpanHandler, krate: ast::Crate) -> ast::Crate { + let mut fld = CfgAttrFolder { + diag: diagnostic, + config: krate.config.clone(), + }; + fld.fold_crate(krate) +} + +impl<'a> fold::Folder for CfgAttrFolder<'a> { + fn fold_attribute(&mut self, attr: ast::Attribute) -> Option { + if !attr.check_name("cfg_attr") { + return fold::noop_fold_attribute(attr, self); + } + + let (cfg, mi) = match attr.meta_item_list() { + Some([ref cfg, ref mi]) => (cfg, mi), + _ => { + self.diag.span_err(attr.span, "expected `#[cfg_attr(, )]`"); + return None; + } + }; + + if attr::cfg_matches(self.diag, &self.config[], &cfg) { + Some(respan(mi.span, ast::Attribute_ { + id: attr::mk_attr_id(), + style: attr.node.style, + value: mi.clone(), + is_sugared_doc: false, + })) + } else { + None + } + } + + // Need the ability to run pre-expansion. + fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac { + fold::noop_fold_mac(mac, self) + } +} diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs index 778b2cabea622..64ae6162ef4e5 100644 --- a/src/libsyntax/ext/base.rs +++ b/src/libsyntax/ext/base.rs @@ -528,8 +528,6 @@ fn initial_syntax_expander_table(ecfg: &expand::ExpansionConfig) -> SyntaxEnv { syntax_expanders.insert(intern("cfg"), builtin_normal_expander( ext::cfg::expand_cfg)); - syntax_expanders.insert(intern("cfg_attr"), - Modifier(box ext::cfg_attr::expand)); syntax_expanders.insert(intern("trace_macros"), builtin_normal_expander( ext::trace_macros::expand_trace_macros)); diff --git a/src/libsyntax/ext/cfg_attr.rs b/src/libsyntax/ext/cfg_attr.rs deleted file mode 100644 index 72eaa3e47bec6..0000000000000 --- a/src/libsyntax/ext/cfg_attr.rs +++ /dev/null @@ -1,34 +0,0 @@ -// Copyright 2014 The Rust Project Developers. See the COPYRIGHT -// file at the top-level directory of this distribution and at -// http://rust-lang.org/COPYRIGHT. -// -// Licensed under the Apache License, Version 2.0 or the MIT license -// , at your -// option. This file may not be copied, modified, or distributed -// except according to those terms. - -use ast; -use attr; -use codemap::Span; -use ext::base::ExtCtxt; -use ext::build::AstBuilder; -use ptr::P; - -pub fn expand(cx: &mut ExtCtxt, sp: Span, mi: &ast::MetaItem, it: P) -> P { - let (cfg, attr) = match mi.node { - ast::MetaList(_, ref mis) if mis.len() == 2 => (&mis[0], &mis[1]), - _ => { - cx.span_err(sp, "expected `#[cfg_attr(, )]`"); - return it; - } - }; - - let mut out = (*it).clone(); - if attr::cfg_matches(&cx.parse_sess.span_diagnostic, &cx.cfg, &**cfg) { - out.attrs.push(cx.attribute(attr.span, attr.clone())); - } - - P(out) -} - diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs index 08e795ef80d04..41850ada3e62b 100644 --- a/src/libsyntax/lib.rs +++ b/src/libsyntax/lib.rs @@ -96,7 +96,6 @@ pub mod ext { pub mod base; pub mod build; pub mod cfg; - pub mod cfg_attr; pub mod concat; pub mod concat_idents; pub mod deriving; diff --git a/src/test/compile-fail/cfg-attr-cfg-2.rs b/src/test/compile-fail/cfg-attr-cfg-2.rs new file mode 100644 index 0000000000000..b71a3be5dcea4 --- /dev/null +++ b/src/test/compile-fail/cfg-attr-cfg-2.rs @@ -0,0 +1,18 @@ +// Copyright 2015 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. +// +// error-pattern: main function not found +// compile-flags: --cfg foo + +// main is conditionally compiled, but the conditional compilation +// is conditional too! + +#[cfg_attr(foo, cfg(bar))] +fn main() { } diff --git a/src/test/compile-fail/cfg-attr-crate-2.rs b/src/test/compile-fail/cfg-attr-crate-2.rs new file mode 100644 index 0000000000000..4867dd8d0b4ab --- /dev/null +++ b/src/test/compile-fail/cfg-attr-crate-2.rs @@ -0,0 +1,17 @@ +// Copyright 2015 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. +// +// compile-flags: --cfg broken + +// https://github.com/rust-lang/rust/issues/21833#issuecomment-72353044 + +#![cfg_attr(broken, no_std)] //~ ERROR no_std is experimental + +fn main() { } diff --git a/src/test/run-pass/cfg-attr-cfg.rs b/src/test/run-pass/cfg-attr-cfg.rs new file mode 100644 index 0000000000000..09ab70194864f --- /dev/null +++ b/src/test/run-pass/cfg-attr-cfg.rs @@ -0,0 +1,15 @@ +// Copyright 2015 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// main is conditionally compiled, but the conditional compilation +// is conditional too! + +#[cfg_attr(foo, cfg(bar))] +fn main() { } diff --git a/src/test/run-pass/cfg-attr-crate.rs b/src/test/run-pass/cfg-attr-crate.rs new file mode 100644 index 0000000000000..e6bd8afad280b --- /dev/null +++ b/src/test/run-pass/cfg-attr-crate.rs @@ -0,0 +1,15 @@ +// Copyright 2015 The Rust Project Developers. See the COPYRIGHT +// file at the top-level directory of this distribution and at +// http://rust-lang.org/COPYRIGHT. +// +// Licensed under the Apache License, Version 2.0 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// https://github.com/rust-lang/rust/issues/21833#issuecomment-72353044 + +#![cfg_attr(not_used, no_std)] + +fn main() { }