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Auto merge of #51762 - petrochenkov:oh-hi-mark, r=oli-obk
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hygiene: Implement transparent marks and use them for call-site hygiene in proc-macros

Fixes #50050
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bors committed Jun 30, 2018
2 parents acf50b7 + 84f1bc8 commit bfc1ee4
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Showing 40 changed files with 549 additions and 169 deletions.
2 changes: 1 addition & 1 deletion src/libproc_macro/diagnostic.rs
Original file line number Diff line number Diff line change
Expand Up @@ -97,7 +97,7 @@ impl Diagnostic {
/// Emit the diagnostic.
#[unstable(feature = "proc_macro", issue = "38356")]
pub fn emit(self) {
::__internal::with_sess(move |(sess, _)| {
::__internal::with_sess(move |sess, _| {
let handler = &sess.span_diagnostic;
let level = __internal::level_to_internal_level(self.level);
let mut diag = rustc::DiagnosticBuilder::new(handler, level, &*self.message);
Expand Down
95 changes: 58 additions & 37 deletions src/libproc_macro/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -58,8 +58,7 @@ use syntax::parse::{self, token};
use syntax::symbol::{keywords, Symbol};
use syntax::tokenstream;
use syntax::parse::lexer::{self, comments};
use syntax_pos::{FileMap, Pos, SyntaxContext, FileName};
use syntax_pos::hygiene::Mark;
use syntax_pos::{FileMap, Pos, FileName};

/// The main type provided by this crate, representing an abstract stream of
/// tokens, or, more specifically, a sequence of token trees.
Expand Down Expand Up @@ -109,6 +108,7 @@ impl TokenStream {
/// Attempts to break the string into tokens and parse those tokens into a token stream.
/// May fail for a number of reasons, for example, if the string contains unbalanced delimiters
/// or characters not existing in the language.
/// All tokens in the parsed stream get `Span::call_site()` spans.
///
/// NOTE: Some errors may cause panics instead of returning `LexError`. We reserve the right to
/// change these errors into `LexError`s later.
Expand All @@ -117,17 +117,10 @@ impl FromStr for TokenStream {
type Err = LexError;

fn from_str(src: &str) -> Result<TokenStream, LexError> {
__internal::with_sess(|(sess, mark)| {
let src = src.to_string();
let name = FileName::ProcMacroSourceCode;
let expn_info = mark.expn_info().unwrap();
let call_site = expn_info.call_site;
// notify the expansion info that it is unhygienic
let mark = Mark::fresh(mark);
mark.set_expn_info(expn_info);
let span = call_site.with_ctxt(SyntaxContext::empty().apply_mark(mark));
let stream = parse::parse_stream_from_source_str(name, src, sess, Some(span));
Ok(__internal::token_stream_wrap(stream))
__internal::with_sess(|sess, data| {
Ok(__internal::token_stream_wrap(parse::parse_stream_from_source_str(
FileName::ProcMacroSourceCode, src.to_string(), sess, Some(data.call_site.0)
)))
})
}
}
Expand Down Expand Up @@ -184,8 +177,6 @@ impl iter::FromIterator<TokenStream> for TokenStream {
#[unstable(feature = "proc_macro", issue = "38356")]
pub mod token_stream {
use syntax::tokenstream;
use syntax_pos::DUMMY_SP;

use {TokenTree, TokenStream, Delimiter};

/// An iterator over `TokenStream`'s `TokenTree`s.
Expand Down Expand Up @@ -214,7 +205,7 @@ pub mod token_stream {
// need to flattened during iteration over stream's token trees.
// Eventually this needs to be removed in favor of keeping original token trees
// and not doing the roundtrip through AST.
if tree.span().0 == DUMMY_SP {
if tree.span().0.is_dummy() {
if let TokenTree::Group(ref group) = tree {
if group.delimiter() == Delimiter::None {
self.cursor.insert(group.stream.clone().0);
Expand Down Expand Up @@ -284,10 +275,7 @@ impl Span {
/// A span that resolves at the macro definition site.
#[unstable(feature = "proc_macro", issue = "38356")]
pub fn def_site() -> Span {
::__internal::with_sess(|(_, mark)| {
let call_site = mark.expn_info().unwrap().call_site;
Span(call_site.with_ctxt(SyntaxContext::empty().apply_mark(mark)))
})
::__internal::with_sess(|_, data| data.def_site)
}

/// The span of the invocation of the current procedural macro.
Expand All @@ -296,7 +284,7 @@ impl Span {
/// at the macro call site will be able to refer to them as well.
#[unstable(feature = "proc_macro", issue = "38356")]
pub fn call_site() -> Span {
::__internal::with_sess(|(_, mark)| Span(mark.expn_info().unwrap().call_site))
::__internal::with_sess(|_, data| data.call_site)
}

/// The original source file into which this span points.
Expand Down Expand Up @@ -1243,7 +1231,7 @@ impl TokenTree {
}

Interpolated(_) => {
__internal::with_sess(|(sess, _)| {
__internal::with_sess(|sess, _| {
let tts = token.interpolated_to_tokenstream(sess, span);
tt!(Group::new(Delimiter::None, TokenStream(tts)))
})
Expand Down Expand Up @@ -1354,20 +1342,21 @@ pub mod __internal {
pub use quote::{LiteralKind, SpannedSymbol, Quoter, unquote};

use std::cell::Cell;
use std::ptr;

use syntax::ast;
use syntax::ext::base::ExtCtxt;
use syntax::ext::hygiene::Mark;
use syntax::ptr::P;
use syntax::parse::{self, ParseSess};
use syntax::parse::token::{self, Token};
use syntax::tokenstream;
use syntax_pos::{BytePos, Loc, DUMMY_SP};
use syntax_pos::hygiene::{Mark, SyntaxContext, Transparency};

use super::{TokenStream, LexError};
use super::{TokenStream, LexError, Span};

pub fn lookup_char_pos(pos: BytePos) -> Loc {
with_sess(|(sess, _)| sess.codemap().lookup_char_pos(pos))
with_sess(|sess, _| sess.codemap().lookup_char_pos(pos))
}

pub fn new_token_stream(item: P<ast::Item>) -> TokenStream {
Expand All @@ -1380,7 +1369,7 @@ pub mod __internal {
}

pub fn token_stream_parse_items(stream: TokenStream) -> Result<Vec<P<ast::Item>>, LexError> {
with_sess(move |(sess, _)| {
with_sess(move |sess, _| {
let mut parser = parse::stream_to_parser(sess, stream.0);
let mut items = Vec::new();

Expand Down Expand Up @@ -1411,16 +1400,30 @@ pub mod __internal {
expand: fn(TokenStream) -> TokenStream);
}

#[derive(Clone, Copy)]
pub struct ProcMacroData {
pub def_site: Span,
pub call_site: Span,
}

#[derive(Clone, Copy)]
struct ProcMacroSess {
parse_sess: *const ParseSess,
data: ProcMacroData,
}

// Emulate scoped_thread_local!() here essentially
thread_local! {
static CURRENT_SESS: Cell<(*const ParseSess, Mark)> =
Cell::new((0 as *const _, Mark::root()));
static CURRENT_SESS: Cell<ProcMacroSess> = Cell::new(ProcMacroSess {
parse_sess: ptr::null(),
data: ProcMacroData { def_site: Span(DUMMY_SP), call_site: Span(DUMMY_SP) },
});
}

pub fn set_sess<F, R>(cx: &ExtCtxt, f: F) -> R
where F: FnOnce() -> R
{
struct Reset { prev: (*const ParseSess, Mark) }
struct Reset { prev: ProcMacroSess }

impl Drop for Reset {
fn drop(&mut self) {
Expand All @@ -1430,24 +1433,42 @@ pub mod __internal {

CURRENT_SESS.with(|p| {
let _reset = Reset { prev: p.get() };
p.set((cx.parse_sess, cx.current_expansion.mark));

// No way to determine def location for a proc macro right now, so use call location.
let location = cx.current_expansion.mark.expn_info().unwrap().call_site;
// Opaque mark was already created by expansion, now create its transparent twin.
// We can't use the call-site span literally here, even if it appears to provide
// correct name resolution, because it has all the `ExpnInfo` wrong, so the edition
// checks, lint macro checks, macro backtraces will all break.
let opaque_mark = cx.current_expansion.mark;
let transparent_mark = Mark::fresh_cloned(opaque_mark);
transparent_mark.set_transparency(Transparency::Transparent);

let to_span = |mark| Span(location.with_ctxt(SyntaxContext::empty().apply_mark(mark)));
p.set(ProcMacroSess {
parse_sess: cx.parse_sess,
data: ProcMacroData {
def_site: to_span(opaque_mark),
call_site: to_span(transparent_mark),
},
});
f()
})
}

pub fn in_sess() -> bool
{
let p = CURRENT_SESS.with(|p| p.get());
!p.0.is_null()
!CURRENT_SESS.with(|sess| sess.get()).parse_sess.is_null()
}

pub fn with_sess<F, R>(f: F) -> R
where F: FnOnce((&ParseSess, Mark)) -> R
where F: FnOnce(&ParseSess, &ProcMacroData) -> R
{
let p = CURRENT_SESS.with(|p| p.get());
assert!(!p.0.is_null(), "proc_macro::__internal::with_sess() called \
before set_parse_sess()!");
f(unsafe { (&*p.0, p.1) })
let sess = CURRENT_SESS.with(|sess| sess.get());
if sess.parse_sess.is_null() {
panic!("procedural macro API is used outside of a procedural macro");
}
f(unsafe { &*sess.parse_sess }, &sess.data)
}
}

Expand Down
11 changes: 3 additions & 8 deletions src/librustc/hir/map/definitions.rs
Original file line number Diff line number Diff line change
Expand Up @@ -484,12 +484,7 @@ impl Definitions {
#[inline]
pub fn opt_span(&self, def_id: DefId) -> Option<Span> {
if def_id.krate == LOCAL_CRATE {
let span = self.def_index_to_span.get(&def_id.index).cloned().unwrap_or(DUMMY_SP);
if span != DUMMY_SP {
Some(span)
} else {
None
}
self.def_index_to_span.get(&def_id.index).cloned()
} else {
None
}
Expand Down Expand Up @@ -586,8 +581,8 @@ impl Definitions {
self.opaque_expansions_that_defined.insert(index, expansion);
}

// The span is added if it isn't DUMMY_SP
if span != DUMMY_SP {
// The span is added if it isn't dummy
if !span.is_dummy() {
self.def_index_to_span.insert(index, span);
}

Expand Down
6 changes: 3 additions & 3 deletions src/librustc/middle/stability.rs
Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ use ty::{self, TyCtxt};
use middle::privacy::AccessLevels;
use session::DiagnosticMessageId;
use syntax::symbol::Symbol;
use syntax_pos::{Span, MultiSpan, DUMMY_SP};
use syntax_pos::{Span, MultiSpan};
use syntax::ast;
use syntax::ast::{NodeId, Attribute};
use syntax::feature_gate::{GateIssue, emit_feature_err, find_lang_feature_accepted_version};
Expand Down Expand Up @@ -687,7 +687,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
let msp: MultiSpan = span.into();
let cm = &self.sess.parse_sess.codemap();
let span_key = msp.primary_span().and_then(|sp: Span|
if sp != DUMMY_SP {
if !sp.is_dummy() {
let file = cm.lookup_char_pos(sp.lo()).file;
if file.name.is_macros() {
None
Expand Down Expand Up @@ -725,7 +725,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Checker<'a, 'tcx> {
match item.node {
hir::ItemExternCrate(_) => {
// compiler-generated `extern crate` items have a dummy span.
if item.span == DUMMY_SP { return }
if item.span.is_dummy() { return }

let def_id = self.tcx.hir.local_def_id(item.id);
let cnum = match self.tcx.extern_mod_stmt_cnum(def_id) {
Expand Down
2 changes: 1 addition & 1 deletion src/librustc/ty/query/plumbing.rs
Original file line number Diff line number Diff line change
Expand Up @@ -708,7 +708,7 @@ macro_rules! define_queries {

// FIXME(eddyb) Get more valid Span's on queries.
pub fn default_span(&self, tcx: TyCtxt<'_, $tcx, '_>, span: Span) -> Span {
if span != DUMMY_SP {
if !span.is_dummy() {
return span;
}
// The def_span query is used to calculate default_span,
Expand Down
2 changes: 1 addition & 1 deletion src/librustc_codegen_llvm/debuginfo/metadata.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1662,7 +1662,7 @@ pub fn create_global_var_metadata(cx: &CodegenCx,
let var_scope = get_namespace_for_item(cx, def_id);
let span = tcx.def_span(def_id);

let (file_metadata, line_number) = if span != syntax_pos::DUMMY_SP {
let (file_metadata, line_number) = if !span.is_dummy() {
let loc = span_start(cx, span);
(file_metadata(cx, &loc.file.name, LOCAL_CRATE), loc.line as c_uint)
} else {
Expand Down
2 changes: 1 addition & 1 deletion src/librustc_codegen_llvm/debuginfo/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -219,7 +219,7 @@ pub fn create_function_debug_context<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
let span = mir.span;

// This can be the case for functions inlined from another crate
if span == syntax_pos::DUMMY_SP {
if span.is_dummy() {
// FIXME(simulacrum): Probably can't happen; remove.
return FunctionDebugContext::FunctionWithoutDebugInfo;
}
Expand Down
16 changes: 8 additions & 8 deletions src/librustc_errors/emitter.rs
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@

use self::Destination::*;

use syntax_pos::{DUMMY_SP, FileMap, Span, MultiSpan};
use syntax_pos::{FileMap, Span, MultiSpan};

use {Level, CodeSuggestion, DiagnosticBuilder, SubDiagnostic, CodeMapperDyn, DiagnosticId};
use snippet::{Annotation, AnnotationType, Line, MultilineAnnotation, StyledString, Style};
Expand Down Expand Up @@ -216,7 +216,7 @@ impl EmitterWriter {

if let Some(ref cm) = self.cm {
for span_label in msp.span_labels() {
if span_label.span == DUMMY_SP {
if span_label.span.is_dummy() {
continue;
}

Expand Down Expand Up @@ -730,7 +730,7 @@ impl EmitterWriter {
let mut max = 0;
if let Some(ref cm) = self.cm {
for primary_span in msp.primary_spans() {
if primary_span != &DUMMY_SP {
if !primary_span.is_dummy() {
let hi = cm.lookup_char_pos(primary_span.hi());
if hi.line > max {
max = hi.line;
Expand All @@ -739,7 +739,7 @@ impl EmitterWriter {
}
if !self.short_message {
for span_label in msp.span_labels() {
if span_label.span != DUMMY_SP {
if !span_label.span.is_dummy() {
let hi = cm.lookup_char_pos(span_label.span.hi());
if hi.line > max {
max = hi.line;
Expand Down Expand Up @@ -778,7 +778,7 @@ impl EmitterWriter {

// First, find all the spans in <*macros> and point instead at their use site
for sp in span.primary_spans() {
if *sp == DUMMY_SP {
if sp.is_dummy() {
continue;
}
let call_sp = cm.call_span_if_macro(*sp);
Expand All @@ -790,7 +790,7 @@ impl EmitterWriter {
// Only show macro locations that are local
// and display them like a span_note
if let Some(def_site) = trace.def_site_span {
if def_site == DUMMY_SP {
if def_site.is_dummy() {
continue;
}
if always_backtrace {
Expand Down Expand Up @@ -830,7 +830,7 @@ impl EmitterWriter {
span.push_span_label(label_span, label_text);
}
for sp_label in span.span_labels() {
if sp_label.span == DUMMY_SP {
if sp_label.span.is_dummy() {
continue;
}
if cm.span_to_filename(sp_label.span.clone()).is_macros() &&
Expand Down Expand Up @@ -1003,7 +1003,7 @@ impl EmitterWriter {
// Make sure our primary file comes first
let (primary_lo, cm) = if let (Some(cm), Some(ref primary_span)) =
(self.cm.as_ref(), msp.primary_span().as_ref()) {
if primary_span != &&DUMMY_SP {
if !primary_span.is_dummy() {
(cm.lookup_char_pos(primary_span.lo()), cm)
} else {
emit_to_destination(&buffer.render(), level, &mut self.dst, self.short_message)?;
Expand Down
8 changes: 5 additions & 3 deletions src/librustc_metadata/creader.rs
Original file line number Diff line number Diff line change
Expand Up @@ -569,9 +569,11 @@ impl<'a> CrateLoader<'a> {
fn register_bang_proc_macro(&mut self,
name: &str,
expand: fn(TokenStream) -> TokenStream) {
let expand = SyntaxExtension::ProcMacro(
Box::new(BangProcMacro { inner: expand }), false, self.edition
);
let expand = SyntaxExtension::ProcMacro {
expander: Box::new(BangProcMacro { inner: expand }),
allow_internal_unstable: false,
edition: self.edition,
};
self.extensions.push((Symbol::intern(name), Lrc::new(expand)));
}
}
Expand Down
7 changes: 5 additions & 2 deletions src/librustc_metadata/cstore_impl.rs
Original file line number Diff line number Diff line change
Expand Up @@ -518,8 +518,11 @@ impl CrateStore for cstore::CStore {
return LoadedMacro::ProcMacro(proc_macros[id.index.to_proc_macro_index()].1.clone());
} else if data.name == "proc_macro" &&
self.get_crate_data(id.krate).item_name(id.index) == "quote" {
let ext = SyntaxExtension::ProcMacro(Box::new(::proc_macro::__internal::Quoter),
true, data.root.edition);
let ext = SyntaxExtension::ProcMacro {
expander: Box::new(::proc_macro::__internal::Quoter),
allow_internal_unstable: true,
edition: data.root.edition,
};
return LoadedMacro::ProcMacro(Lrc::new(ext));
}

Expand Down
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