Inline final methods defined in traits

In order to inline a final trait method, callsites of such methods are
first re-written from interface calls to static calls of the trait's
implementation class. Then inlining proceeds as ususal.

One problem that came up during development was that mixin methods are
added to class symbols only for classes being compiled, but not for
others. In order to inline a mixin method, we need the InlineInfo,
which so far was built using the class (and method) symbols. So we had
a problem with separate compilation.

Looking up the symbol from a given classfile name was already known to
be brittle (it's also one of the weak points of the current inliner),
so we changed the strategy. Now the InlineInfo for every class is
encoded in a new classfile attribute.

This classfile attribute is relatively small, because all strings it
references (class internal names, method names, method descriptors)
would exist anyway in the constant pool, so it just adds a few
references.

When building the InlineInfo for a class symbol, we only look at the
symbol properties for symbols being compiled in the current run. For
unpickled symbols, we build the InlineInfo by reading the classfile
attribute.

This change also adds delambdafy:method classes to currentRun.symSource.
Otherwise, currentRun.compiles(lambdaClass) is false.

1 files changed, 2 insertions, 2 deletions

diff --git a/test/junit/scala/tools/nsc/backend/jvm/opt/CompactLocalVariablesTest.scala b/test/junit/scala/tools/nsc/backend/jvm/opt/CompactLocalVariablesTest.scala
index fc748196d0..76492cfa23 100644
--- a/test/junit/scala/tools/nsc/backend/jvm/opt/CompactLocalVariablesTest.scala
+++ b/test/junit/scala/tools/nsc/backend/jvm/opt/CompactLocalVariablesTest.scala
@@ -17,8 +17,8 @@ class CompactLocalVariablesTest {
 
   // recurse-unreachable-jumps is required for eliminating catch blocks, in the first dce round they
   // are still live.only after eliminating the empty handler the catch blocks become unreachable.
-  val methodOptCompiler     = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:unreachable-code,recurse-unreachable-jumps,compact-locals")
-  val noCompactVarsCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:unreachable-code,recurse-unreachable-jumps")
+  val methodOptCompiler     = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:unreachable-code,compact-locals")
+  val noCompactVarsCompiler = newCompiler(extraArgs = "-target:jvm-1.6 -Ybackend:GenBCode -Yopt:unreachable-code")
 
   @Test
   def compactUnused(): Unit = {