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incr.comp.: Track expanded spans instead of FileMaps. #42175
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@@ -103,18 +103,11 @@ impl FileLoader for RealFileLoader { | |||
// | |||
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pub struct CodeMap { | |||
// The `files` field should not be visible outside of libsyntax so that we | |||
// can do proper dependency tracking. | |||
pub(super) files: RefCell<Vec<Rc<FileMap>>>, |
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Do we need the pub(super)
here anymore? I guess it doesn't hurt...
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Yes, there is one instance in libsyntax where it is accessed via borrow_mut()
.
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seems good to me
@bors r+ |
📌 Commit 21dd71f has been approved by |
…x-1, r=nikomatsakis incr.comp.: Track expanded spans instead of FileMaps. This PR removes explicit tracking of FileMaps in response to rust-lang#42101. The reasoning behind being able to just *not* track access to FileMaps is similar to why we don't track access to the `DefId->DefPath` map: 1. One can only get ahold of a `Span` value by accessing the HIR (for local things) or a `metadata::schema::Entry` (for things from external crates). 2. For both of these things we compute a hash that incorporates the *expanded spans*, that is, what we hash is in the (FileMap independent) format `filename:line:col`. 3. Consequently, everything that emits a span should already be tracked via its dependency to something that has the span included in its hash and changes would be detected via that hash. One caveat here is that we have to be conservative when exporting things in metadata. A crate can be built without debuginfo and would thus by default not incorporate most spans into the metadata hashes. However, a downstream crate can make an inline copy of things in the upstream crate and span changes in the upstream crate would then go undetected, even if the downstream uses them (e.g. by emitting debuginfo for an inlined function). For this reason, we always incorporate spans into metadata hashes for now (there might be more efficient ways to handle this safely when red-green tracking is implemented). r? @nikomatsakis
…x-1, r=nikomatsakis incr.comp.: Track expanded spans instead of FileMaps. This PR removes explicit tracking of FileMaps in response to rust-lang#42101. The reasoning behind being able to just *not* track access to FileMaps is similar to why we don't track access to the `DefId->DefPath` map: 1. One can only get ahold of a `Span` value by accessing the HIR (for local things) or a `metadata::schema::Entry` (for things from external crates). 2. For both of these things we compute a hash that incorporates the *expanded spans*, that is, what we hash is in the (FileMap independent) format `filename:line:col`. 3. Consequently, everything that emits a span should already be tracked via its dependency to something that has the span included in its hash and changes would be detected via that hash. One caveat here is that we have to be conservative when exporting things in metadata. A crate can be built without debuginfo and would thus by default not incorporate most spans into the metadata hashes. However, a downstream crate can make an inline copy of things in the upstream crate and span changes in the upstream crate would then go undetected, even if the downstream uses them (e.g. by emitting debuginfo for an inlined function). For this reason, we always incorporate spans into metadata hashes for now (there might be more efficient ways to handle this safely when red-green tracking is implemented). r? @nikomatsakis
…x-1, r=nikomatsakis incr.comp.: Track expanded spans instead of FileMaps. This PR removes explicit tracking of FileMaps in response to rust-lang#42101. The reasoning behind being able to just *not* track access to FileMaps is similar to why we don't track access to the `DefId->DefPath` map: 1. One can only get ahold of a `Span` value by accessing the HIR (for local things) or a `metadata::schema::Entry` (for things from external crates). 2. For both of these things we compute a hash that incorporates the *expanded spans*, that is, what we hash is in the (FileMap independent) format `filename:line:col`. 3. Consequently, everything that emits a span should already be tracked via its dependency to something that has the span included in its hash and changes would be detected via that hash. One caveat here is that we have to be conservative when exporting things in metadata. A crate can be built without debuginfo and would thus by default not incorporate most spans into the metadata hashes. However, a downstream crate can make an inline copy of things in the upstream crate and span changes in the upstream crate would then go undetected, even if the downstream uses them (e.g. by emitting debuginfo for an inlined function). For this reason, we always incorporate spans into metadata hashes for now (there might be more efficient ways to handle this safely when red-green tracking is implemented). r? @nikomatsakis
…x-1, r=nikomatsakis incr.comp.: Track expanded spans instead of FileMaps. This PR removes explicit tracking of FileMaps in response to rust-lang#42101. The reasoning behind being able to just *not* track access to FileMaps is similar to why we don't track access to the `DefId->DefPath` map: 1. One can only get ahold of a `Span` value by accessing the HIR (for local things) or a `metadata::schema::Entry` (for things from external crates). 2. For both of these things we compute a hash that incorporates the *expanded spans*, that is, what we hash is in the (FileMap independent) format `filename:line:col`. 3. Consequently, everything that emits a span should already be tracked via its dependency to something that has the span included in its hash and changes would be detected via that hash. One caveat here is that we have to be conservative when exporting things in metadata. A crate can be built without debuginfo and would thus by default not incorporate most spans into the metadata hashes. However, a downstream crate can make an inline copy of things in the upstream crate and span changes in the upstream crate would then go undetected, even if the downstream uses them (e.g. by emitting debuginfo for an inlined function). For this reason, we always incorporate spans into metadata hashes for now (there might be more efficient ways to handle this safely when red-green tracking is implemented). r? @nikomatsakis
…matsakis incr.comp.: Track expanded spans instead of FileMaps. This PR removes explicit tracking of FileMaps in response to #42101. The reasoning behind being able to just *not* track access to FileMaps is similar to why we don't track access to the `DefId->DefPath` map: 1. One can only get ahold of a `Span` value by accessing the HIR (for local things) or a `metadata::schema::Entry` (for things from external crates). 2. For both of these things we compute a hash that incorporates the *expanded spans*, that is, what we hash is in the (FileMap independent) format `filename:line:col`. 3. Consequently, everything that emits a span should already be tracked via its dependency to something that has the span included in its hash and changes would be detected via that hash. One caveat here is that we have to be conservative when exporting things in metadata. A crate can be built without debuginfo and would thus by default not incorporate most spans into the metadata hashes. However, a downstream crate can make an inline copy of things in the upstream crate and span changes in the upstream crate would then go undetected, even if the downstream uses them (e.g. by emitting debuginfo for an inlined function). For this reason, we always incorporate spans into metadata hashes for now (there might be more efficient ways to handle this safely when red-green tracking is implemented). r? @nikomatsakis
☀️ Test successful - status-appveyor, status-travis |
This PR removes explicit tracking of FileMaps in response to #42101. The reasoning behind being able to just not track access to FileMaps is similar to why we don't track access to the
DefId->DefPath
map:Span
value by accessing the HIR (for local things) or ametadata::schema::Entry
(for things from external crates).filename:line:col
.One caveat here is that we have to be conservative when exporting things in metadata. A crate can be built without debuginfo and would thus by default not incorporate most spans into the metadata hashes. However, a downstream crate can make an inline copy of things in the upstream crate and span changes in the upstream crate would then go undetected, even if the downstream uses them (e.g. by emitting debuginfo for an inlined function). For this reason, we always incorporate spans into metadata hashes for now (there might be more efficient ways to handle this safely when red-green tracking is implemented).
r? @nikomatsakis