RFR: 8264593: debug.cpp utilities should be available in product builds.

[Kevin Walls]

This is a pull request to move the ifndef PRODUCT in src/hotspot/share/utilities/debug.cpp, and add JNIEXPORT for symbol visibility on Windows.

With these changes, we can use gdb on a live Linux process of a product build JVM, and call debug.cpp utilities.
e.g. "call universe()", or "call hsfind(0xADDRESS)".

(I found that making calls in the JLI_Launch thread (gdb's thread 1) will crash, but switching first to a JavaThread works.)

In Visual Studio use the Immediate window, just type the function name.  Verified that without the changes, the symbols can't be seen/called.

Printing happens on the LIVE jvm's tty (not the gdb session).


WizardMode is a develop flag, can't be changed in a product build, so avoid changing that in the debug() utility.


pa() is left ifndef PRODUCT, as the class AllocatedObj is ifndef PRODUCT in src/hotspot/share/memory/allocation.hpp


pns(...) uses frame fr(sp, fp, pc); but we have an ifndef PRODUCT on frame constructor:  frame(void* sp, void* fp, void* pc);
Leave pns and pns2 ifndef PRODUCT.


File size changes:
Linux: libjvm.so becomes 8904 bytes larger.
Windows: jvm.dll becomes 6656 bytes larger.

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Commit messages:
 - 8264593: debug.cpp utilities should be available in product builds.

Changes: https://git.openjdk.java.net/jdk/pull/3307/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3307&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8264593
  Stats: 42 lines in 1 file changed: 3 ins; 7 del; 32 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3307.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3307/head:pull/3307

PR: https://git.openjdk.java.net/jdk/pull/3307