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author | Jason Zaugg <jzaugg@gmail.com> | 2016-11-08 11:14:59 +1000 |
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committer | Jason Zaugg <jzaugg@gmail.com> | 2016-11-08 14:31:16 +1000 |
commit | 44dac961782aa1193493c181e8423d7751c013ee (patch) | |
tree | 356ad7f4c5b32f7dd1ade2ccfa464e9235d6fcc7 /src/reflect | |
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')
4 files changed, 17 insertions, 3 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 diff --git a/src/reflect/scala/reflect/internal/Types.scala b/src/reflect/scala/reflect/internal/Types.scala index f8679616d1..5e1bf37b80 100644 --- a/src/reflect/scala/reflect/internal/Types.scala +++ b/src/reflect/scala/reflect/internal/Types.scala @@ -4487,6 +4487,7 @@ trait Types debuglog(s"transposed irregular matrix!? tps=$tps argss=$argss") NoType case Some(argsst) => + var capturedParamIds = 0 val args = map2(sym.typeParams, argsst) { (tparam, as0) => val as = as0.distinct if (as.size == 1) as.head @@ -4508,8 +4509,10 @@ trait Types else { // Martin: I removed this, because incomplete. Not sure there is a good way to fix it. For the moment we // just err on the conservative side, i.e. with a bound that is too high. // if(!(tparam.info.bounds contains tparam)) //@M can't deal with f-bounds, see #2251 + capturedParamIds += 1 + val capturedParamId = capturedParamIds - val qvar = commonOwner(as) freshExistential "" setInfo TypeBounds(g, l) + val qvar = commonOwner(as).freshExistential("", capturedParamId) setInfo TypeBounds(g, l) capturedParams += qvar qvar.tpe } diff --git a/src/reflect/scala/reflect/internal/tpe/TypeMaps.scala b/src/reflect/scala/reflect/internal/tpe/TypeMaps.scala index ba4f2bec4b..08219c0634 100644 --- a/src/reflect/scala/reflect/internal/tpe/TypeMaps.scala +++ b/src/reflect/scala/reflect/internal/tpe/TypeMaps.scala @@ -512,6 +512,8 @@ private[internal] trait TypeMaps { && isBaseClassOfEnclosingClass(sym.owner) ) + private var capturedThisIds= 0 + private def nextCapturedThisId() = { capturedThisIds += 1; capturedThisIds } /** Creates an existential representing a type parameter which appears * in the prefix of a ThisType. */ @@ -519,7 +521,7 @@ private[internal] trait TypeMaps { capturedParams find (_.owner == clazz) match { case Some(p) => p.tpe case _ => - val qvar = clazz freshExistential nme.SINGLETON_SUFFIX setInfo singletonBounds(pre) + val qvar = clazz.freshExistential(nme.SINGLETON_SUFFIX, nextCapturedThisId()) setInfo singletonBounds(pre) _capturedParams ::= qvar debuglog(s"Captured This(${clazz.fullNameString}) seen from $seenFromPrefix: ${qvar.defString}") qvar.tpe diff --git a/src/reflect/scala/reflect/runtime/SynchronizedSymbols.scala b/src/reflect/scala/reflect/runtime/SynchronizedSymbols.scala index 237afa082b..4e7ddda54e 100644 --- a/src/reflect/scala/reflect/runtime/SynchronizedSymbols.scala +++ b/src/reflect/scala/reflect/runtime/SynchronizedSymbols.scala @@ -10,7 +10,9 @@ private[reflect] trait SynchronizedSymbols extends internal.Symbols { self: Symb private lazy val atomicIds = new java.util.concurrent.atomic.AtomicInteger(0) override protected def nextId() = atomicIds.incrementAndGet() + @deprecated("Global existential IDs no longer used", "2.12.1") private lazy val atomicExistentialIds = new java.util.concurrent.atomic.AtomicInteger(0) + @deprecated("Global existential IDs no longer used", "2.12.1") override protected def nextExistentialId() = atomicExistentialIds.incrementAndGet() private lazy val _recursionTable = mkThreadLocalStorage(immutable.Map.empty[Symbol, Int]) |