8365829: Multiple definitions of static 'phase_names'

[fandreuz]

• 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.

---

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Issue

• JDK-8365829: Multiple definitions of static 'phase_names' (Enhancement - P4)

Reviewers

• Kim Barrett (@kimbarrett - Reviewer)

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8365829: Multiple definitions of static 'phase_names'

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• e1c58f8: 8360540: nmethod entry barriers of new nmethods should be disarmed
• f0498c2: 8364764: java/nio/channels/vthread/BlockingChannelOps.java subtests timed out
• 8e44856: 8365180: Remove sun.awt.windows.WInputMethod.finalize()
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• 03: Full - Incremental (90e9c537)
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[kimbarrett]

Is there a reason for these to be public rather than private?
Also, we "always" prefix data member names with a leading underscore; see Style Guide.

[fandreuz]

phase_name is accessed by static CompilerPhaseType find_phase, should we make it a friend of the CompilerPhaseTypeHelper?

[fandreuz]

Underscore: 90e9c53

[kimbarrett]

Don't make it a friend, make it a static member function, and fix the one
caller (later in this file). (The definition of find_phase could be moved to
the new .cpp file.) I think the caller also has an ODR problem, with calls
from different including TUs getting a different file-scoped find_phase.

It looks like there might be a lot of file-scoped static declarations from
header files in our code. I've made a note to look into this.

[fandreuz]

Sure: cc7da3a

[kimbarrett]

Looks good.

[fandreuz]

/integrate

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@fandreuz
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