RFR: 8365829: Multiple definitions of static 'phase_names'

[Francesco Andreuzzi]

- `opto/phasetype.hpp` defines `static const char* phase_names[]`
- `compiler/compilerEvent.cpp` defines `static GrowableArray<const char*>* phase_names`

This is not a problem when the two files are compiled as different translation units, but it causes a build failure if any of them is pulled in by a precompiled header:


/jdk/src/hotspot/share/compiler/compilerEvent.cpp:59:36: error: redefinition of 'phase_names' with a different type: 'GrowableArray<const char *> *' vs 'const char *[100]'
   59 | static GrowableArray<const char*>* phase_names = nullptr;
      | ^
/jdk/src/hotspot/share/opto/phasetype.hpp:147:20: note: previous definition is here
  147 | static const char* phase_names[] = {
      | ^
/jdk/src/hotspot/share/compiler/compilerEvent.cpp:67:39: error: member reference base type 'const char *' is not a structure or union
   67 | const u4 nof_entries = phase_names->length();
      | ~~~~~~~~~~~^ ~~~~~~
/jdk/src/hotspot/share/compiler/compilerEvent.cpp:71:31: error: member reference base type 'const char *' is not a structure or union
   71 | writer.write(phase_names->at(i));
      | ~~~~~~~~~~~^ ~~
/jdk/src/hotspot/share/compiler/compilerEvent.cpp:77:34: error: member reference base type 'const char *' is not a structure or union
   77 | for (int i = 0; i < phase_names->length(); i++) {
      | ~~~~~~~~~~~^ ~~~~~~
/jdk/src/hotspot/share/compiler/compilerEvent.cpp:78:35: error: member reference base type 'const char *' is not a structure or union
   78 | const char* name = phase_names->at(i);
      | ~~~~~~~~~~~^ ~~
/jdk/src/hotspot/share/compiler/compilerEvent.cpp:91:9: error: comparison of array 'phase_names' equal to a null pointer is always false [-Werror,-Wtautological-pointer-compare]
   91 | if (phase_names == nullptr) {
      | ^~~~~~~~~~~ ~~~~~~~
/jdk/src/hotspot/share/compiler/compilerEvent.cpp:92:19: error: array type 'const char *[100]' is not assignable
   92 | phase_names = new (mtInternal) GrowableArray<const char*>(100, mtCompiler);
      | ~~~~~~~~~~~ ^
/jdk/src/hotspot/share/compiler/compilerEvent.cpp:103:24: error: member reference base type 'const char *' is not a structure or union
  103 | index = phase_names->length();
      | ~~~~~~~~~~~^ ~~~~~~
/jdk/src/hotspot/share/compiler/compilerEvent.cpp:104:16: error: member reference base type 'const char *' is not a structure or union
  104 | phase_names->append(use_strdup ? os::strdup(phase_name) : phase_name);
      | ~~~~~~~~~~~^ ~~~~~~
9 errors generated.


Passes `tier1`.

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

Commit messages:
 - fix

Changes: https://git.openjdk.org/jdk/pull/26851/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26851&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365829
  Stats: 8 lines in 2 files changed: 2 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/26851.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26851/head:pull/26851

PR: https://git.openjdk.org/jdk/pull/26851