RFR: 8289230: Move PlatformXXX class declarations out of os_xxx.hpp [v2]

[Coleen Phillimore]

On Tue, 28 Jun 2022 18:38:10 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> There are only two implementations of these classes (one for windows, and one for posix):
>> 
>> - PlatformEvent
>> - PlatformParker
>> - PlatformMutex
>> - PlatformMonitor
>> - ThreadCrashProtection
>> 
>> Before this PR, these classes are declared in os_xxx.hpp. This causes excessive inclusion of the large header file os.hpp by popular headers such as mutex.hpp, which needs only the declaration of PlatformMutex but not the other stuff in os.hpp
>> 
>> This PR moves the declarations to park_posix.hpp, mutex_posix.hpp, etc.
>> 
>> Note:  ideally, the definition of PlatformParker/PlatformEvent should be moved to park_posix.cpp, and PlatformMutex/PlatformMonitor should be moved to mutex_posix.cpp. However, the definition of these 4 classes are intertwined, so I'll leave them inside os_posix.cpp for now. (Same for the Windows version).
>
> Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
> 
>   fixed comments

I very much like this incremental approach to reducing our over-inclusion.

src/hotspot/share/runtime/mutex.hpp line 203:

> 201:   #ifndef PRODUCT
> 202:     void print_on(outputStream* st) const;
> 203:     void print() const                      { /*print_on(::tty); */ } // FIXME

Can you move this print implementation into the .cpp file?

src/hotspot/share/runtime/threadCrashProtection.hpp line 42:

> 40: #else
> 41: # error "No ThreadCrashProtection implementation provided for this OS"
> 42: #endif

Shouldn't you use this?
#define OS_HEADER(basename)            XSTR(OS_HEADER_STEM(basename).hpp)

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Marked as reviewed by coleenp (Reviewer).

PR: https://git.openjdk.org/jdk/pull/9303