RFR: 8260012: Reduce inclusion of collectedHeap.hpp and heapInspection.hpp

[Thomas Schatzl]

On Tue, 2 Feb 2021 04:18:24 GMT, Ioi Lam <iklam at openjdk.org> wrote:

> collectedHeap.hpp is included by 477 out of 1000 .o files in HotSpot. This file in turn includes many other complex header files.
> 
> In many cases, an object file only directly includes this file via:
> 
> - memAllocator.hpp (which does not actually use collectedHeap.hpp)
> - oop.inline.hpp and compressedOops.inline.hpp (only use collectedHeap.hpp in asserts via `Universe::heap()->is_in()`).
> 
> By refactoring the above 3 files, we can reduce the .o files that include collectedHeap.hpp to 242.
> 
> This RFE also removes the unnecessary inclusion of heapInspection.hpp from collectedHeap.hpp.
> 
> Build time of HotSpot is reduced for about 1%.
> 
> Tested with mach5: tier1, builds-tier2, builds-tier3, builds-tier4 and builds-tier5. Also locally: aarch64, arm, ppc64, s390, x86, and zero.

Checked a few includes for missing ones; obviously they are included transitively so add as you see fit.

src/hotspot/share/gc/shared/memAllocator.hpp line 30:

> 28: #include "memory/memRegion.hpp"
> 29: #include "oops/oopsHierarchy.hpp"
> 30: #include "runtime/thread.hpp"

`utilities/globalDefinitions.hpp` for `HeapWord` is missing.

src/hotspot/share/oops/compressedOops.inline.hpp line 28:

> 26: #define SHARE_OOPS_COMPRESSEDOOPS_INLINE_HPP
> 27: 
> 28: #include "gc/shared/collectedHeap.hpp"

`utilities/globalDefinitions.hpp` for `*PTR_FORMAT` and others is missing.

src/hotspot/share/oops/oop.inline.hpp line 28:

> 26: #define SHARE_OOPS_OOP_INLINE_HPP
> 27: 
> 28: #include "gc/shared/collectedHeap.hpp"

`utilities/globalDefinitions.hpp` for `HeapWord` is missing.
`globals.hpp` for some globals.
`oopsHierarchy.hpp` for `narrowKlass`
`utilties/debug.hpp` for `assert`

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Marked as reviewed by tschatzl (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/2347