diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc_span/src/hygiene.rs | 121 |
1 files changed, 61 insertions, 60 deletions
diff --git a/compiler/rustc_span/src/hygiene.rs b/compiler/rustc_span/src/hygiene.rs index 4390085cd04..e7a8dee27f5 100644 --- a/compiler/rustc_span/src/hygiene.rs +++ b/compiler/rustc_span/src/hygiene.rs @@ -75,6 +75,21 @@ pub struct SyntaxContextData { } impl SyntaxContextData { + fn new( + (parent, outer_expn, outer_transparency): SyntaxContextKey, + opaque: SyntaxContext, + opaque_and_semitransparent: SyntaxContext, + ) -> SyntaxContextData { + SyntaxContextData { + outer_expn, + outer_transparency, + parent, + opaque, + opaque_and_semitransparent, + dollar_crate_name: kw::DollarCrate, + } + } + fn root() -> SyntaxContextData { SyntaxContextData { outer_expn: ExpnId::root(), @@ -543,7 +558,7 @@ impl HygieneData { ) -> SyntaxContext { assert_ne!(expn_id, ExpnId::root()); if transparency == Transparency::Opaque { - return self.apply_mark_internal(ctxt, expn_id, transparency); + return self.alloc_ctxt(ctxt, expn_id, transparency); } let call_site_ctxt = self.expn_data(expn_id).call_site.ctxt(); @@ -554,7 +569,7 @@ impl HygieneData { }; if call_site_ctxt.is_root() { - return self.apply_mark_internal(ctxt, expn_id, transparency); + return self.alloc_ctxt(ctxt, expn_id, transparency); } // Otherwise, `expn_id` is a macros 1.0 definition and the call site is in a @@ -567,74 +582,60 @@ impl HygieneData { // // See the example at `test/ui/hygiene/legacy_interaction.rs`. for (expn_id, transparency) in self.marks(ctxt) { - call_site_ctxt = self.apply_mark_internal(call_site_ctxt, expn_id, transparency); + call_site_ctxt = self.alloc_ctxt(call_site_ctxt, expn_id, transparency); } - self.apply_mark_internal(call_site_ctxt, expn_id, transparency) + self.alloc_ctxt(call_site_ctxt, expn_id, transparency) } - fn apply_mark_internal( + /// Allocate a new context with the given key, or retrieve it from cache if the given key + /// already exists. The auxiliary fields are calculated from the key. + fn alloc_ctxt( &mut self, - ctxt: SyntaxContext, + parent: SyntaxContext, expn_id: ExpnId, transparency: Transparency, ) -> SyntaxContext { - let syntax_context_data = &mut self.syntax_context_data; - debug_assert!(!syntax_context_data[ctxt.0 as usize].is_decode_placeholder()); - let mut opaque = syntax_context_data[ctxt.0 as usize].opaque; - let mut opaque_and_semitransparent = - syntax_context_data[ctxt.0 as usize].opaque_and_semitransparent; - - if transparency >= Transparency::Opaque { - let parent = opaque; - opaque = *self - .syntax_context_map - .entry((parent, expn_id, transparency)) - .or_insert_with(|| { - let new_opaque = SyntaxContext::from_usize(syntax_context_data.len()); - syntax_context_data.push(SyntaxContextData { - outer_expn: expn_id, - outer_transparency: transparency, - parent, - opaque: new_opaque, - opaque_and_semitransparent: new_opaque, - dollar_crate_name: kw::DollarCrate, - }); - new_opaque - }); - } + debug_assert!(!self.syntax_context_data[parent.0 as usize].is_decode_placeholder()); - if transparency >= Transparency::SemiTransparent { - let parent = opaque_and_semitransparent; - opaque_and_semitransparent = *self - .syntax_context_map - .entry((parent, expn_id, transparency)) - .or_insert_with(|| { - let new_opaque_and_semitransparent = - SyntaxContext::from_usize(syntax_context_data.len()); - syntax_context_data.push(SyntaxContextData { - outer_expn: expn_id, - outer_transparency: transparency, - parent, - opaque, - opaque_and_semitransparent: new_opaque_and_semitransparent, - dollar_crate_name: kw::DollarCrate, - }); - new_opaque_and_semitransparent - }); + // Look into the cache first. + let key = (parent, expn_id, transparency); + if let Some(ctxt) = self.syntax_context_map.get(&key) { + return *ctxt; } - let parent = ctxt; - *self.syntax_context_map.entry((parent, expn_id, transparency)).or_insert_with(|| { - syntax_context_data.push(SyntaxContextData { - outer_expn: expn_id, - outer_transparency: transparency, - parent, - opaque, - opaque_and_semitransparent, - dollar_crate_name: kw::DollarCrate, - }); - SyntaxContext::from_usize(syntax_context_data.len() - 1) - }) + // Reserve a new syntax context. + let ctxt = SyntaxContext::from_usize(self.syntax_context_data.len()); + self.syntax_context_data.push(SyntaxContextData::decode_placeholder()); + self.syntax_context_map.insert(key, ctxt); + + // Opaque and semi-transparent versions of the parent. Note that they may be equal to the + // parent itself. E.g. `parent_opaque` == `parent` if the expn chain contains only opaques, + // and `parent_opaque_and_semitransparent` == `parent` if the expn contains only opaques + // and semi-transparents. + let parent_opaque = self.syntax_context_data[parent.0 as usize].opaque; + let parent_opaque_and_semitransparent = + self.syntax_context_data[parent.0 as usize].opaque_and_semitransparent; + + // Evaluate opaque and semi-transparent versions of the new syntax context. + let (opaque, opaque_and_semitransparent) = match transparency { + Transparency::Transparent => (parent_opaque, parent_opaque_and_semitransparent), + Transparency::SemiTransparent => ( + parent_opaque, + // Will be the same as `ctxt` if the expn chain contains only opaques and semi-transparents. + self.alloc_ctxt(parent_opaque_and_semitransparent, expn_id, transparency), + ), + Transparency::Opaque => ( + // Will be the same as `ctxt` if the expn chain contains only opaques. + self.alloc_ctxt(parent_opaque, expn_id, transparency), + // Will be the same as `ctxt` if the expn chain contains only opaques and semi-transparents. + self.alloc_ctxt(parent_opaque_and_semitransparent, expn_id, transparency), + ), + }; + + // Fill the full data, now that we have it. + self.syntax_context_data[ctxt.as_u32() as usize] = + SyntaxContextData::new(key, opaque, opaque_and_semitransparent); + ctxt } } |