RFR: 8195129: System.load() fails to load from unicode paths [v4]

[Maxim Kartashev]

> Character strings within JVM are produced and consumed in several formats. Strings come from/to Java in the UTF8 format and POSIX APIs (like fprintf() or dlopen()) consume strings also in UTF8. On Windows, however, the situation is far less simple: some new(er) APIs expect UTF16 (wide-character strings), some older APIs can only work with strings in a "platform" format, where not all UTF8 characters can be represented; which ones can depends on the current "code page".
> 
> This commit switches the Windows version of native library loading code to using the new UTF16 API `LoadLibraryW()` and attempts to streamline the use of various string formats in the surrounding code. 
> 
> Namely, exception messages are made to consume strings explicitly in the UTF8 format, while logging functions (that end up using legacy Windows API) are made to consume "platform" strings in most cases. One exception is `JVM_LoadLibrary()` logging where the UTF8 name of the library is logged, which can, of course, be fixed, but was considered not worth the additional code (NB: this isn't a new bug).
> 
> The test runs in a separate JVM in order to make NIO happy about non-ASCII characters in the file name; tests are executed with LC_ALL=C and that doesn't let NIO work with non-ASCII file names even on Linux or MacOS.
> 
> Tested by running `test/hotspot/jtreg:tier1` on Linux and `jtreg:test/hotspot/jtreg/runtime` on Windows 10. The new test (`   jtreg:test/hotspot/jtreg/runtime/jni/loadLibraryUnicode`) was explicitly ran on those platforms as well.
> 
> Results from Linux:
> 
> Test summary
> ==============================
>    TEST                                              TOTAL  PASS  FAIL ERROR   
>    jtreg:test/hotspot/jtreg:tier1                     1784  1784     0     0   
> ==============================
> TEST SUCCESS
> 
> 
> Building target 'run-test-only' in configuration 'linux-x86_64-server-release'
> Test selection 'jtreg:test/hotspot/jtreg/runtime/jni/loadLibraryUnicode', will run:
> * jtreg:test/hotspot/jtreg/runtime/jni/loadLibraryUnicode
> 
> Running test 'jtreg:test/hotspot/jtreg/runtime/jni/loadLibraryUnicode'
> Passed: runtime/jni/loadLibraryUnicode/LoadLibraryUnicodeTest.java
> Test results: passed: 1
> 
> 
> Results from Windows 10:
> 
> Test summary
> ==============================
>    TEST                                              TOTAL  PASS  FAIL ERROR
>    jtreg:test/hotspot/jtreg/runtime                    746   746     0     0
> ==============================
> TEST SUCCESS
> Finished building target 'run-test-only' in configuration 'windows-x86_64-server-fastdebug'
> 
> 
> Building target 'run-test-only' in configuration 'windows-x86_64-server-fastdebug'
> Test selection 'test/hotspot/jtreg/runtime/jni/loadLibraryUnicode', will run:
> * jtreg:test/hotspot/jtreg/runtime/jni/loadLibraryUnicode
> 
> Running test 'jtreg:test/hotspot/jtreg/runtime/jni/loadLibraryUnicode'
> Passed: runtime/jni/loadLibraryUnicode/LoadLibraryUnicodeTest.java
> Test results: passed: 1

Maxim Kartashev has updated the pull request incrementally with one additional commit since the last revision:

  Updated Java_jdk_internal_loader_NativeLibraries_load() to use a new helper function
  to get the library name encoded as true UTF-8 (not in "modified UTF-8" form).
  Also updated the test to automatically pass if "UTF-8" is not supported by NIO
  on the platform.

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4169/files
  - new: https://git.openjdk.java.net/jdk/pull/4169/files/c8ef8b64..97c918ca

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4169&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4169&range=02-03

  Stats: 71 lines in 4 files changed: 57 ins; 6 del; 8 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4169.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4169/head:pull/4169

PR: https://git.openjdk.java.net/jdk/pull/4169