8027455: Improve symbol table scan times during gc pauses
Summary: Parallelize string table and symbol table scan during remark and full GC. Some additional statistics output if the experimental flag G1TraceStringSymbolTableScrubbing is set.
Reviewed-by: mgerdin, coleenp, brutisso

Summary: Enable CHECK_UNHANDLED_OOPS in fastdebug builds across all supported platforms.
Reviewed-by: coleenp, hseigel, dholmes, stefank, twisti, ihse, rdurbin
Contributed-by: lois.foltan@oracle.com

Summary: SymbolTable and StringTable can make calls to GC_locker::is_active() outside a safepoint. This isn't safe because the GC_locker active state (lock count) is only updated at a safepoint and only remains valid as long as _needs_gc is true. However, outside a safepoint_needs_gc can change to false at any time, which makes it impossible to do a correct call to is_active() in that context. In this case these calls can just be removed since the input argument to basic_add() should never be on the heap and so there's no need to check the GC_locker state. This change also adjusts the assert() in is_active() to makes sure all calls to this function are always done under a safepoint.
Reviewed-by: brutisso, dcubed
Contributed-by: per.liden@oracle.com

Summary: Add -XX:+VerifyStringTableAtExit option and code to verify StringTable invariants.
Reviewed-by: rdurbin, sspitsyn, coleenp

Summary: Parallelize the scanning of the intern string table by having each GC worker claim a given number of buckets. Changes were also reviewed by Per Liden <per.liden@oracle.com>.
Reviewed-by: tschatzl, stefank, twisti

Summary: Combine the calls to StringTable::unlink and StringTable::oops_do in Parallel Scavenge.
Reviewed-by: pliden, coleenp

Summary: The string in StringTable is not used by CDS anymore. Remove the unnecessary code in preparation for 8015422: Large performance hit when the StringTable is walked twice in Parallel Scavenge
Reviewed-by: pliden, tschatzl, coleenp

Summary: Added info for the string/symbol objects and the hash entries
Reviewed-by: coleenp, rbackman

Summary: Instead of terminating the VM, throw OutOfMemoryError exceptions.
Reviewed-by: coleenp, dholmes

Summary: Add convenience method in StringTable, add WhiteBox method and simple sanity test
Reviewed-by: mgerdin, zgu
Contributed-by: leonid.mesnik@oracle.com

Summary: -Xshare:dump was creating a Symbol in C_heap.  There's an assert there that jdk jprt wasn't hitting because it was only done in product
Reviewed-by: dholmes, hseigel, iklam

Summary: renamed to hash_code
Reviewed-by: dholmes, coleenp, brutisso
Contributed-by: erik.helin@oracle.com

Summary: Remove PermGen, allocate meta-data in metaspace linked to class loaders, rewrite GC walking, rewrite and rename metadata to be C++ classes
Reviewed-by: jmasa, stefank, never, coleenp, kvn, brutisso, mgerdin, dholmes, jrose, twisti, roland
Contributed-by: Njmasa &lt;jon.masamitsu@oracle.com&gt;, stefank &lt;stefan.karlsson@oracle.com&gt;, mgerdin &lt;mikael.gerdin@oracle.com&gt;, never <tom.rodriguez@oracle.com>

Summary: Made new_hash() overloaded rather than a virtual function so SA code doesn't need to be changed.
Reviewed-by: kvn, acorn, dholmes, fparain

7151532: DCmd for hotspot native memory tracking
Summary: Implementation of native memory tracking phase 1, which tracks VM native memory usage, and related DCmd
Reviewed-by: acorn, coleenp, fparain

Summary: Cannot delete _buckets and HashtableEntries in shared space (CDS)
Reviewed-by: acorn, kvn, dlong, dcubed, kamg

Summary: Use an alternate version of hashing algorithm for symbol string tables and after a certain bucket size to improve performance
Reviewed-by: pbk, kamg, dlong, kvn, fparain

Summary: Move symbol allocation to an arena so NMT doesn't have to track them at startup.
Reviewed-by: never, kamg, zgu

Summary: Added a nop tracing infrastructure, JFR makefile changes and other infrastructure used only by JFR.
Reviewed-by: acorn, sspitsyn
Contributed-by: markus.gronlund@oracle.com

Reviewed-by: kvn, kamg, jcoomes

Reviewed-by: never, coleenp, ysr, jwilhelm

Summary: Put symbol printing under Verbose and WizardMode so you can get this information if you really want it.
Reviewed-by: phh, stefank, never, dholmes, jcoomes

Summary: move symbols from permgen into C heap and reference count them
Reviewed-by: never, acorn, jmasa, stefank

Summary: Replaced MakeDeps and the includeDB files with more standardized solutions.
Reviewed-by: coleenp, kvn, kamg

Summary: Change all the Sun copyrights to Oracle copyright
Reviewed-by: ohair

Summary: preparatory but separable changes for method handles
Reviewed-by: kvn, never

Summary: I have collected some typos I have found while looking at the code.
Reviewed-by: kvn, never