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author | Jason Zaugg <jzaugg@gmail.com> | 2016-02-09 22:12:26 +1000 |
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committer | Jason Zaugg <jzaugg@gmail.com> | 2016-02-09 22:12:26 +1000 |
commit | c3fcd4e5b0c8f03862ecf4f92fd43cf2fb8f5066 (patch) | |
tree | b7f6f0fbbbf514687bc20e18c94317cb9905c673 /src | |
parent | ef4ed496c59e4b54266aaf20db917fb41bb9f1e4 (diff) | |
download | scala-c3fcd4e5b0c8f03862ecf4f92fd43cf2fb8f5066.tar.gz scala-c3fcd4e5b0c8f03862ecf4f92fd43cf2fb8f5066.tar.bz2 scala-c3fcd4e5b0c8f03862ecf4f92fd43cf2fb8f5066.zip |
Micro optimise Symbol#fullName
The old approach of recursively calling `fullNameAsName`
creates a lot of garbage for intermediate results, in
addition to needless interning of those results into
the name table.
This commit instead creates a string buffer of the
correct capacity and writes the component names
directly into this.
I compared old and new approaches and this shows a 2x
speedup.
```
scala> val th = ichi.bench.Thyme.warmed(verbose = print)
th: ichi.bench.Thyme = ichi.bench.Thyme@1643e817
scala> val w_old = th.Warm(sym.fullNameAsNameOld('.'))
w_old: th.Warm[$r.intp.global.Name] = ichi.bench.Thyme$Warm@7a8d001b
scala> val w_new = th.Warm(sym.fullNameAsName('.'))
w_new: th.Warm[$r.intp.global.Name] = ichi.bench.Thyme$Warm@1ec14586
scala> th.pbenchOffWarm("", x => println(x))(w_old, 10, "old")(w_new, 10, "new")
Benchmark comparison (in 4.084 s)
old vs new
Significantly different (p ~= 0)
Time ratio: 0.53572 95% CI 0.51618 - 0.55525 (n=20)
old 64.54 ns 95% CI 62.41 ns - 66.67 ns
new 34.57 ns 95% CI 34.04 ns - 35.11 ns
res3: $r.intp.global.Name = scala.collection.parallel.mutable.ParSeq
```
It is still expensive enough that we should still consider
caching. The call to full name in `classBTypeFromSymbol`
in the new backed is a prime candidate for optimization.
Diffstat (limited to 'src')
-rw-r--r-- | src/reflect/scala/reflect/internal/Symbols.scala | 38 |
1 files changed, 25 insertions, 13 deletions
diff --git a/src/reflect/scala/reflect/internal/Symbols.scala b/src/reflect/scala/reflect/internal/Symbols.scala index 11e740117d..3b9ee9048a 100644 --- a/src/reflect/scala/reflect/internal/Symbols.scala +++ b/src/reflect/scala/reflect/internal/Symbols.scala @@ -1256,8 +1256,9 @@ trait Symbols extends api.Symbols { self: SymbolTable => /** These should be moved somewhere like JavaPlatform. */ def javaSimpleName: Name = addModuleSuffix(simpleName.dropLocal) - def javaBinaryName: Name = addModuleSuffix(fullNameInternal('/')) - def javaClassName: String = addModuleSuffix(fullNameInternal('.')).toString + def javaBinaryName: Name = name.newName(javaBinaryNameString) + def javaBinaryNameString: String = fullName('/', moduleSuffix) + def javaClassName: String = fullName('.', moduleSuffix) /** The encoded full path name of this symbol, where outer names and inner names * are separated by `separator` characters. @@ -1265,18 +1266,29 @@ trait Symbols extends api.Symbols { self: SymbolTable => * Never adds id. * Drops package objects. */ - final def fullName(separator: Char): String = fullNameAsName(separator).toString - - /** Doesn't drop package objects, for those situations (e.g. classloading) - * where the true path is needed. - */ - private def fullNameInternal(separator: Char): Name = ( - if (isRoot || isRootPackage || this == NoSymbol) name - else if (owner.isEffectiveRoot) name - else effectiveOwner.enclClass.fullNameAsName(separator) append (separator, name) - ) + final def fullName(separator: Char): String = fullName(separator, "") + + private def fullName(separator: Char, suffix: CharSequence): String = { + var b: java.lang.StringBuffer = null + def loop(size: Int, sym: Symbol): Unit = { + val symName = sym.name + val nSize = symName.length - (if (symName.endsWith(nme.LOCAL_SUFFIX_STRING)) 1 else 0) + if (sym.isRoot || sym.isRootPackage || sym == NoSymbol || sym.owner.isEffectiveRoot) { + val capacity = size + nSize + b = new java.lang.StringBuffer(capacity) + b.append(chrs, symName.start, nSize) + } else { + loop(size + nSize + 1, sym.effectiveOwner.enclClass) + b.append(separator) + b.append(chrs, symName.start, nSize) + } + } + loop(suffix.length(), this) + b.append(suffix) + b.toString + } - def fullNameAsName(separator: Char): Name = fullNameInternal(separator).dropLocal + def fullNameAsName(separator: Char): Name = name.newName(fullName(separator, "")) /** The encoded full path name of this symbol, where outer names and inner names * are separated by periods. |