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| author | Jason Zaugg <jzaugg@gmail.com> | 2016-11-08 11:14:59 +1000 |
|---|---|---|
| committer | Jason Zaugg <jzaugg@gmail.com> | 2016-11-08 14:31:16 +1000 |
| commit | 44dac961782aa1193493c181e8423d7751c013ee (patch) | |
| tree | 356ad7f4c5b32f7dd1ade2ccfa464e9235d6fcc7 /src/reflect/scala/reflect/internal/Symbols.scala | |
| parent | 10c609e750a7089055b126e6231e5ddb2f2e8623 (diff) | |
| download | scala-44dac961782aa1193493c181e8423d7751c013ee.tar.gz scala-44dac961782aa1193493c181e8423d7751c013ee.tar.bz2 scala-44dac961782aa1193493c181e8423d7751c013ee.zip | |
Avoid name table pollution with fresh existentials
During large compilations runs, the large numbers of globally unique
fresh names for existentials captured from prefixes of `asSeenFrom`.
is a) somewhat wasteful (all these names are interned in the name table)
, and, b) form a pathological case for the current implementation of
`Names#hashValue`, which leads to overfull hash-buckets in the name table.
`hashValue` should probably be improved, but my attempts to do so have
shown a small performance degradation in some benchmarks. So this commit
starts by being more frugal with these names, only uniquely naming
within an `asSeenFrom` operation.
References scala/scala-dev#246
Diffstat (limited to 'src/reflect/scala/reflect/internal/Symbols.scala')
| -rw-r--r-- | src/reflect/scala/reflect/internal/Symbols.scala | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/src/reflect/scala/reflect/internal/Symbols.scala b/src/reflect/scala/reflect/internal/Symbols.scala index 8d77e334db..5cac9fb465 100644 --- a/src/reflect/scala/reflect/internal/Symbols.scala +++ b/src/reflect/scala/reflect/internal/Symbols.scala @@ -34,9 +34,13 @@ trait Symbols extends api.Symbols { self: SymbolTable => def recursionTable = _recursionTable def recursionTable_=(value: immutable.Map[Symbol, Int]) = _recursionTable = value + @deprecated("Global existential IDs no longer used", "2.12.1") private var existentialIds = 0 + @deprecated("Global existential IDs no longer used", "2.12.1") protected def nextExistentialId() = { existentialIds += 1; existentialIds } - protected def freshExistentialName(suffix: String) = newTypeName("_" + nextExistentialId() + suffix) + @deprecated("Use overload that accepts an id", "2.12.1") + protected def freshExistentialName(suffix: String): TypeName = freshExistentialName(suffix, nextExistentialId()) + protected def freshExistentialName(suffix: String, id: Int): TypeName = newTypeName("_" + id + suffix) // Set the fields which point companions at one another. Returns the module. def connectModuleToClass(m: ModuleSymbol, moduleClass: ClassSymbol): ModuleSymbol = { @@ -440,8 +444,11 @@ trait Symbols extends api.Symbols { self: SymbolTable => def newGADTSkolem(name: TypeName, origin: Symbol, info: Type): TypeSkolem = newTypeSkolemSymbol(name, origin, origin.pos, origin.flags & ~(EXISTENTIAL | PARAM) | GADT_SKOLEM_FLAGS) setInfo info + @deprecated("Use overload that accepts an id", "2.12.1") final def freshExistential(suffix: String): TypeSymbol = newExistential(freshExistentialName(suffix), pos) + final def freshExistential(suffix: String, id: Int): TypeSymbol = + newExistential(freshExistentialName(suffix, id), pos) /** Type skolems are type parameters ''seen from the inside'' * Assuming a polymorphic method m[T], its type is a PolyType which has a TypeParameter |