8265403: consolidate definition of CPU features #3558

dougxc · 2021-04-17T20:18:31Z

While porting JDK-8224974 to Graal, I noticed that new CPU features were defined for x86 and AArch64 without being exposed via JVMCI. To avoid this problem in future, this PR updates x86 and AArch64 to define CPU features with a single macro that is used to generate enum declarations as well as vmstructs entries.

In addition, the JVMCI API is updated to exposes the new CPU feature constants and now has a check that ensure these constants are in sync with the underlying macro definition.

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Issue

JDK-8265403: consolidate definition of CPU features

Reviewers

Vladimir Kozlov (@vnkozlov - Reviewer)
Ioi Lam (@iklam - Reviewer)

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Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/3558/head:pull/3558
$ git checkout pull/3558

Update a local copy of the PR:
$ git checkout pull/3558
$ git pull https://git.openjdk.java.net/jdk pull/3558/head

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$ git pr checkout 3558

View PR using the GUI difftool:
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https://git.openjdk.java.net/jdk/pull/3558.diff

bridgekeeper · 2021-04-17T20:19:00Z

👋 Welcome back dnsimon! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

openjdk · 2021-04-17T20:20:37Z

@dougxc The following labels will be automatically applied to this pull request:

build
hotspot

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing lists. If you would like to change these labels, use the /label pull request command.

dougxc · 2021-04-17T20:51:38Z

...ses/jdk.vm.ci.hotspot.amd64/src/jdk/vm/ci/hotspot/amd64/AMD64HotSpotJVMCIBackendFactory.java

-        }
+
+        Map<String, Long> constants = config.getStore().getConstants();
+        Function<String, CPUFeature> nameToFeature = name -> name.equals("3DNOW_PREFETCH") ? CPUFeature.AMD_3DNOW_PREFETCH : CPUFeature.valueOf(name);


The AMD_3DNOW_PREFETCH enum constant has to keep its old name to preserve backward compatibility.

dougxc · 2021-04-17T20:53:40Z

src/hotspot/cpu/aarch64/vm_version_aarch64.cpp

-  if (_features & CPU_LSE) strcat(buf, ", lse");
-  if (_features & CPU_SVE) strcat(buf, ", sve");
-  if (_features & CPU_SVE2) strcat(buf, ", sve2");
+#define ADD_FEATURE_IF_SUPPORTED(id, name, bit) if (_features & CPU_##id) strcat(buf, ", " name);


I'm not sure why only some of the supported AArch64 CPU features were being added to _features_string but I assume there's no harm in adding them all.

dougxc · 2021-04-17T20:54:52Z

src/hotspot/cpu/x86/vm_version_x86.hpp

  static const char* _features_names[];

-  // NB! When adding new CPU feature detection consider updating vmStructs_x86.hpp, vmStructs_jvmci.hpp, and VM_Version::get_processor_features().


No need for this comment any more as the derivative declarations are now automatically kept up to date.

mlbridge · 2021-04-18T11:53:09Z

Webrevs

vnkozlov · 2021-04-19T18:27:05Z

/label add hotspot-compiler
/label add hotspot-runtime

openjdk · 2021-04-19T18:27:41Z

@vnkozlov
The hotspot-compiler label was successfully added.

vnkozlov · 2021-04-19T18:28:24Z

/label add hotspot-runtime

openjdk · 2021-04-19T18:28:36Z

@vnkozlov
The hotspot-runtime label was successfully added.

vnkozlov · 2021-04-19T18:28:51Z

/label remove hotspot

openjdk · 2021-04-19T18:29:39Z

@vnkozlov The hotspot-runtime label was already applied.

openjdk · 2021-04-19T18:29:58Z

@vnkozlov
The hotspot label was successfully removed.

vnkozlov

Please, update copyright years in files you touched.

vnkozlov · 2021-04-19T18:33:59Z

src/hotspot/cpu/x86/vm_version_x86.hpp

+    decl(AVX512_VBMI2,      "avx512_vbmi2",      44) /* VBMI2 shift left double instructions */ \
+    decl(AVX512_VBMI,       "avx512_vbmi",       45) /* Vector BMI instructions */ \
+    decl(HV,                "hv",                46) /* Hypervisor instructions */
+#define DECLARE_CPU_FEATURE_FLAG(id, name, bit) CPU_##id = (1ULL << bit),


Add empty line before it to separate CPU_FEATURE_FLAGS macro more clear.

vnkozlov · 2021-04-19T18:57:37Z

src/hotspot/cpu/aarch64/vm_version_aarch64.hpp

+    decl(SVE2,          "sve2",          28)  \
+    decl(STXR_PREFETCH, "stxr_prefetch", 29)  \
+    decl(A53MAC,        "a53mac",        30)
+#define DECLARE_CPU_FEATURE_FLAG(id, name, bit) CPU_##id = (1 << bit),


Add empty line before to separate CPU_FEATURE_FLAGS macro.

vnkozlov · 2021-04-19T18:58:46Z

src/hotspot/cpu/x86/vmStructs_x86.hpp

+#define VM_LONG_CONSTANTS_CPU(declare_constant, declare_preprocessor_constant, declare_c1_constant, declare_c2_constant, declare_c2_preprocessor_constant)
+
+#define DECLARE_LONG_CPU_FEATURE_CONSTANT(id, name, bit) GENERATE_VM_LONG_CONSTANT_ENTRY(VM_Version::CPU_##id)
+#define VM_LONG_CPU_FEATURE_CONSTANTS CPU_FEATURE_FLAGS(DECLARE_LONG_CPU_FEATURE_CONSTANT)


Do we need to keep VM_LONG_CONSTANTS_CPU after you removed its body here and in vmStructs_jvmci.cpp?

What about VM_INT_CONSTANTS_CPU here? vmStructs_jvmci.cpp duplicates it.

vmStructs.cpp and vmStructs_jvmci.cpp are disjoint. This file (i.e. vmStructs_x86.hpp) is only used by vmStructs.cpp.
vmStructs.cpp expects all macros such as VM_LONG_CONSTANTS_CPU to be defined.
vmStructs_jvmci.cpp will provide a dummy definition for missing macros.

Got it. Even so they are empty everywhere :(

vnkozlov · 2021-04-19T19:00:09Z

src/hotspot/share/jvmci/vmStructs_jvmci.cpp

-  declare_constant(VM_Version::CPU_STXR_PREFETCH)       \
-  declare_constant(VM_Version::CPU_A53MAC)
+#define DECLARE_INT_CPU_FEATURE_CONSTANT(id, name, bit) GENERATE_VM_INT_CONSTANT_ENTRY(VM_Version::CPU_##id)
+#define VM_INT_CPU_FEATURE_CONSTANTS CPU_FEATURE_FLAGS(DECLARE_INT_CPU_FEATURE_CONSTANT)


Missing #undef DECLARE_INT_CPU_FEATURE_CONSTANT.

No, it must stay defined up to the point VM_INT_CPU_FEATURE_CONSTANTS is used. Since this is a .cpp file, it's ok to leave it defined.

vnkozlov · 2021-04-19T19:00:22Z

src/hotspot/share/jvmci/vmStructs_jvmci.cpp

-  declare_constant(VM_Version::CPU_AVX512_VBMI)                     \
-  declare_constant(VM_Version::CPU_HV)
+#define DECLARE_LONG_CPU_FEATURE_CONSTANT(id, name, bit) GENERATE_VM_LONG_CONSTANT_ENTRY(VM_Version::CPU_##id)
+#define VM_LONG_CPU_FEATURE_CONSTANTS CPU_FEATURE_FLAGS(DECLARE_LONG_CPU_FEATURE_CONSTANT)


Missing #undef DECLARE_LONG_CPU_FEATURE_CONSTANT.

Same comment as for DECLARE_INT_CPU_FEATURE_CONSTANT.

vnkozlov · 2021-04-19T19:12:19Z

....vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotJVMCIBackendFactory.java

+        for (Entry<String, Long> e : constants.entrySet()) {
+            long bitMask = e.getValue();
+            String key = e.getKey();
+            if (key.startsWith("VM_Version::CPU_")) {


As I understand this code, it goes over constants values passed from VM and Trying to map them to enumType. It catches cases when a value is missing in enumType. What about case when enumType has extra value which is not defined in constants?

We could warn about that but cannot remove it without breaking backwards capability for JVMCI wrt Graal. Such a deleted capability will simply be seen as "not supported" by Graal.

vnkozlov

You need review from Runtime group too.

openjdk · 2021-04-19T20:03:15Z

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

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8265403: consolidate definition of CPU features

Reviewed-by: kvn, iklam

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 105 new commits pushed to the master branch:

8e31229: 8265327: Remove check_safepoint_and_suspend_for_native_trans()
c9b70c8: 8265240: runtime/Thread/SuspendAtExit.java needs updating
891f72f: 8265606: Reduce allocations in AdapterHandlerLibrary::get_adapter
bfc1cd8: 8264320: ShouldNotReachHere in Compile::print_inlining_move_to()
5db64c3: 8265268: Unify ReservedSpace reservation code in initialize and try_reserve_heap
191f1fc: 8265759: Shenandoah: Avoid race for referent in assert
b3a319c: 8264842: IGV: different nodes sharing idx are treated as equal
95f0fd6: 8265696: Move CDS sources to src/hotspot/shared/cds
a715b09: 8265798: Minimal build broken by JDK-8261090
13d3263: 8265484: Fix up TRAPS usage in GenerateOopMap::compute_map and callers
... and 95 more: https://git.openjdk.java.net/jdk/compare/cb8394a841023b2cf4a9103f47f50e3fd28c5b04...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

iklam

LGTM

dougxc · 2021-04-23T23:32:01Z

Thanks for the reviews @vnkozlov and @iklam.

dougxc · 2021-04-23T23:32:17Z

/integrate

openjdk · 2021-04-23T23:33:08Z

@dougxc Since your change was applied there have been 112 commits pushed to the master branch:

20a373a: 8265393: VM crashes if both -XX:+RecordDynamicDumpInfo and -XX:SharedArchiveFile options are specified
6803ab2: 8265880: ProblemList serviceability/dcmd/gc/RunFinalizationTest.java on Linux-X64
e08f506: 8265816: Handle new VectorMaskCast node for x86
bebfae4: 8264208: Console charset API
5aab160: 8265531: doc/building.md should mention homebrew install freetype
d8e638f: 8265794: Remove ProblemList-non-cds-mode
ac23870: 8265831: 8257831 broke Windows x86 build
8e31229: 8265327: Remove check_safepoint_and_suspend_for_native_trans()
c9b70c8: 8265240: runtime/Thread/SuspendAtExit.java needs updating
891f72f: 8265606: Reduce allocations in AdapterHandlerLibrary::get_adapter
... and 102 more: https://git.openjdk.java.net/jdk/compare/cb8394a841023b2cf4a9103f47f50e3fd28c5b04...master

Your commit was automatically rebased without conflicts.

Pushed as commit 5aed446.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

openjdk bot added build build-dev@openjdk.org hotspot hotspot-dev@openjdk.org labels Apr 17, 2021

dougxc force-pushed the JDK-8265403 branch from 31f055a to 9a92ae3 Compare April 17, 2021 20:49

dougxc commented Apr 17, 2021

View reviewed changes

dougxc force-pushed the JDK-8265403 branch from 9a92ae3 to 3217c1f Compare April 17, 2021 20:56

8265403: consolidate definition of CPU features

b69675f

dougxc force-pushed the JDK-8265403 branch from 3217c1f to b69675f Compare April 18, 2021 11:28

dougxc marked this pull request as ready for review April 18, 2021 11:47

openjdk bot added the rfr Pull request is ready for review label Apr 18, 2021

avoid use of a lambda in JVMCI initialization

124019d

dougxc force-pushed the JDK-8265403 branch from bdf9eef to 124019d Compare April 19, 2021 09:42

openjdk bot added the hotspot-compiler hotspot-compiler-dev@openjdk.org label Apr 19, 2021

openjdk bot added the hotspot-runtime hotspot-runtime-dev@openjdk.org label Apr 19, 2021

openjdk bot removed the hotspot hotspot-dev@openjdk.org label Apr 19, 2021

vnkozlov reviewed Apr 19, 2021

View reviewed changes

dougxc added 2 commits April 19, 2021 21:50

added blank lines after macros

5109a39

updated date in copyright

c6be143

vnkozlov approved these changes Apr 19, 2021

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openjdk bot added the ready Pull request is ready to be integrated label Apr 19, 2021

iklam approved these changes Apr 23, 2021

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openjdk bot closed this Apr 23, 2021

openjdk bot added integrated Pull request has been integrated and removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Apr 23, 2021

dougxc deleted the JDK-8265403 branch May 2, 2021 16:15

dougxc restored the JDK-8265403 branch May 2, 2021 16:15

dougxc deleted the JDK-8265403 branch May 2, 2021 16:16

		static const char* _features_names[];

		// NB! When adding new CPU feature detection consider updating vmStructs_x86.hpp, vmStructs_jvmci.hpp, and VM_Version::get_processor_features().

8265403: consolidate definition of CPU features #3558

8265403: consolidate definition of CPU features #3558

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