8330540: Rename the enum type CompileCommand to CompileCommandEnum

[iklam]

CompileCommand is used both as a enum type (compilerOracle.hpp), and a global variable (compiler_globals.hpp).

This makes very awkward to the enum type -- we are forced to use enum CompileCommand in the source code whenever a type is needed:

This simple c++ file illustrates the problem:

enum class CompileCommand { a, b, c };
void foo(CompileCommand x) {}
char* CompileCommand; // can no longer use "CompileCommand" as a type
void good(enum CompileCommand x) {}
void bad(CompileCommand x) {}

$ g++ -c ~/enum.cpp
/home/iklam/enum.cpp:5:6: error: variable or field ?bad? declared void
    5 | void bad(CompileCommand x) {}

The fix is to rename the enum type to CompileCommandEnum.

This also makes it possible to forward-declare CompileCommandEnum (see vmEnum.hpp) without including compilerOracle.hpp. This improves HotSpot build time by reducing the number of .o files that include compilerOracle.hpp from 456 to 16.

---

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Issue

• JDK-8330540: Rename the enum type CompileCommand to CompileCommandEnum (Enhancement - P4)

Reviewers

• Vladimir Kozlov (@vnkozlov - Reviewer)
• Dean Long (@dean-long - Reviewer)

Reviewing

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[bridgekeeper]

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[openjdk]

@iklam This change now passes all automated pre-integration checks.

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8330540: Rename the enum type CompileCommand to CompileCommandEnum

Reviewed-by: kvn, dlong

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[openjdk]

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[mlbridge]

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• 01: Full - Incremental (9d1191b8)
• 00: Full (b60a498f)

[vnkozlov]

Why you need it here?

[iklam]

It's needed by this:

jvmciCompilerToVM.cpp:571:21: error: 'CompilerOracle' has not been declared
  571 |   return !Inline || CompilerOracle::should_not_inline(method) || method->dont_inline();

[vnkozlov]

Good.

[dean-long]

The char* CompileCommand for the flag seems to be used much less than the enum (I could only find it used once). So if we could rename that variable, that would be a simpler solution. But it looks like that would require some advanced macro tricks in DECLARE_FLAGS to allow customization on a per-flag basis.

[iklam]

Thanks @dean-long and @vnkozlov for the review
/integrate

[openjdk]

Going to push as commit 6d56996.
Since your change was applied there have been 14 commits pushed to the master branch:

• f6feeb0: 8330703: Improve link syntax in javax.lang.model.util
• df04358: 8330179: Clean up non-standard use of /** comments in jdk.compiler
• c1dd82b: 8329644: Discuss expected visitor evolution patterns in javax.lang.model.util
• b704e91: 8329433: Reduce nmethod header size
• 8da175d: 8330008: [s390x] Test bit "in-memory" in case of DiagnoseSyncOnValueBasedClasses
• 3c1d1d9: 8320522: Remove code related to RegisterFinalizersAtInit
• 650ca65: 8329330: NoClassDefFoundError: Could not initialize class jdk.jfr.internal.MirrorEvents
• 177092b: 8330569: Rename Nix to Posix in platform-dependent attachListener code
• eb60822: 8310072: JComboBox/DisabledComboBoxFontTestAuto: Enabled and disabled ComboBox does not match in these LAFs: GTK+
• 85261bc: 8330266: RISC-V: Restore frm to RoundingMode::rne after JNI
• ... and 4 more: https://git.openjdk.org/jdk/compare/32946e1882e9b22c983cbba3c6bda3cc7295946a...master

Your commit was automatically rebased without conflicts.

[openjdk]

@iklam Pushed as commit 6d56996.

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