8300255: Introduce interface for GC oop verification in the assembler #12443

fisk · 2023-02-06T15:32:50Z

In the assembly code, there is some generic oop verification code. Said verification may or may not fit a particular GC. In particular, it has not worked well for ZGC for a while, and there is an if (UseZGC). This enhancement aims at generalizing this code, such that a collector can have its own oop verification policy.

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Issue

JDK-8300255: Introduce interface for GC oop verification in the assembler

Reviewers

Fei Yang (@RealFYang - Reviewer)
Axel Boldt-Christmas (@xmas92 - Committer)
Coleen Phillimore (@coleenp - Reviewer)

Contributors

Martin Doerr <mdoerr@openjdk.org>
Axel Boldt-Christmas <aboldtch@openjdk.org>
Yadong Wang <yadongwang@openjdk.org>

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fisk · 2023-02-06T15:33:45Z

/contributor add @TheRealMDoerr

fisk · 2023-02-06T15:34:01Z

/contributor add @xmas92

bridgekeeper · 2023-02-06T15:34:27Z

👋 Welcome back eosterlund! 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.

fisk · 2023-02-06T15:35:11Z

/contributor add @yadongw

fisk · 2023-02-06T15:36:13Z

PPC code contributed by @TheRealMDoerr and RISC-V code contributed by @yadongw. Could you please check that it works on your machines?

openjdk · 2023-02-06T15:36:26Z

@fisk
Contributor Martin Doerr <mdoerr@openjdk.org> successfully added.

openjdk · 2023-02-06T15:38:13Z

@fisk
Contributor Axel Boldt-Christmas <aboldtch@openjdk.org> successfully added.

openjdk · 2023-02-06T15:40:09Z

@fisk
Contributor Yadong Wang <yadongwang@openjdk.org> successfully added.

openjdk · 2023-02-06T15:42:04Z

@fisk The following label will be automatically applied to this pull request:

hotspot

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

mlbridge · 2023-02-06T15:45:29Z

Webrevs

TheRealMDoerr · 2023-02-07T05:14:17Z

PPC code contributed by @TheRealMDoerr and RISC-V code contributed by @yadongw. Could you please check that it works on your machines?

The default version of check_oop doesn't work for ZGC. I suggest to exclude the PPC64 parts here and ship them with the generational ZGC PR. That will reduce effort. Does that make sense?

fisk · 2023-02-07T09:57:54Z

PPC code contributed by @TheRealMDoerr and RISC-V code contributed by @yadongw. Could you please check that it works on your machines?

The default version of check_oop doesn't work for ZGC. I suggest to exclude the PPC64 parts here and ship them with the generational ZGC PR. That will reduce effort. Does that make sense?

Hmm. Looking at the changes of this patch, we used to call __ verify_oop, but now we call check_oop on the barrier set assembler, which in turn has a single implementation which calls __ verify_oop. It seems like this patch currently does not change the behaviour at all to what happened before? While I am perfectly fine removing the PPC changes, I don't think I understand what behaviour this patch changes for PPC.

RealFYang

Hi, seems we need two extra small changes to build on linux-riscv. Thanks.

RealFYang · 2023-02-07T10:28:25Z

src/hotspot/cpu/riscv/gc/z/zBarrierSetAssembler_riscv.hpp

@@ -99,6 +99,8 @@ class ZBarrierSetAssembler : public ZBarrierSetAssemblerBase {
  void generate_c2_load_barrier_stub(MacroAssembler* masm,
                                     ZLoadBarrierStubC2* stub) const;
 #endif // COMPILER2
+
+  virtual void check_oop(MacroAssembler* masm, Register obj, Register tmp1, Register tmp2, Label& error);


Need to remove 'virtual' here.

RealFYang · 2023-02-07T10:29:05Z

src/hotspot/cpu/riscv/gc/z/zBarrierSetAssembler_riscv.cpp

+
+#define __ masm->
+
+void BarrierSetAssembler::check_oop(MacroAssembler* masm, Register obj, Register tmp1, Register tmp2, Label& error) {


Should be 'ZBarrierSetAssembler::check_oop' here.

TheRealMDoerr · 2023-02-07T11:52:40Z

PPC code contributed by @TheRealMDoerr and RISC-V code contributed by @yadongw. Could you please check that it works on your machines?

The default version of check_oop doesn't work for ZGC. I suggest to exclude the PPC64 parts here and ship them with the generational ZGC PR. That will reduce effort. Does that make sense?

Hmm. Looking at the changes of this patch, we used to call __ verify_oop, but now we call check_oop on the barrier set assembler, which in turn has a single implementation which calls __ verify_oop. It seems like this patch currently does not change the behaviour at all to what happened before? While I am perfectly fine removing the PPC changes, I don't think I understand what behaviour this patch changes for PPC.

You're right. VerifyOops is already broken with ZGC on PPC64. You can keep the PPC64 parts as they are. The generational ZGC code will fix the problem. So, I'm fine with this PR.

fisk · 2023-02-07T15:08:08Z

PPC code contributed by @TheRealMDoerr and RISC-V code contributed by @yadongw. Could you please check that it works on your machines?

The default version of check_oop doesn't work for ZGC. I suggest to exclude the PPC64 parts here and ship them with the generational ZGC PR. That will reduce effort. Does that make sense?

Hmm. Looking at the changes of this patch, we used to call __ verify_oop, but now we call check_oop on the barrier set assembler, which in turn has a single implementation which calls __ verify_oop. It seems like this patch currently does not change the behaviour at all to what happened before? While I am perfectly fine removing the PPC changes, I don't think I understand what behaviour this patch changes for PPC.

You're right. VerifyOops is already broken with ZGC on PPC64. You can keep the PPC64 parts as they are. The generational ZGC code will fix the problem. So, I'm fine with this PR.

Okay great - thanks for checking!

fisk · 2023-02-07T15:08:34Z

Hi, seems we need two extra small changes to build on linux-riscv. Thanks.

Thanks for having a look! Hopefully fixed in the latest commit.

RealFYang · 2023-02-08T09:02:53Z

@fisk : Hi, I think we should also add following changes for riscv to make it work:

diff --git a/src/hotspot/cpu/riscv/gc/shared/barrierSetAssembler_riscv.cpp b/src/hotspot/cpu/riscv/gc/shared/barrierSetAssembler_riscv.cpp
index ed53fbf22c8..662de44de29 100644
--- a/src/hotspot/cpu/riscv/gc/shared/barrierSetAssembler_riscv.cpp
+++ b/src/hotspot/cpu/riscv/gc/shared/barrierSetAssembler_riscv.cpp
@@ -316,8 +316,7 @@ void BarrierSetAssembler::check_oop(MacroAssembler* masm, Register obj, Register
   __ mv(tmp2, (intptr_t) Universe::verify_oop_bits());

   // Compare tmp1 and tmp2.
-  __ xorr(tmp1, tmp1, tmp2);
-  __ bnez(tmp1, error);
+  __ bne(tmp1, tmp2, error);

   // Make sure klass is 'reasonable', which is not zero.
   __ load_klass(obj, obj, tmp1); // get klass
diff --git a/src/hotspot/cpu/riscv/gc/z/zBarrierSetAssembler_riscv.cpp b/src/hotspot/cpu/riscv/gc/z/zBarrierSetAssembler_riscv.cpp
index 0741869ddaf..1ebfb8f9e23 100644
--- a/src/hotspot/cpu/riscv/gc/z/zBarrierSetAssembler_riscv.cpp
+++ b/src/hotspot/cpu/riscv/gc/z/zBarrierSetAssembler_riscv.cpp
@@ -449,10 +449,10 @@ void ZBarrierSetAssembler::generate_c1_load_barrier_runtime_stub(StubAssembler*

 void ZBarrierSetAssembler::check_oop(MacroAssembler* masm, Register obj, Register tmp1, Register tmp2, Label& error) {
   // Check if mask is good.
-  // verifies that ZAddressBadMask & x10 == 0
-  __ ld(c_rarg3, Address(xthread, ZThreadLocalData::address_bad_mask_offset()));
-  __ andr(c_rarg2, x10, c_rarg3);
-  __ bnez(c_rarg2, error);
+  // verifies that ZAddressBadMask & obj == 0
+  __ ld(tmp2, Address(xthread, ZThreadLocalData::address_bad_mask_offset()));
+  __ andr(tmp1, obj, tmp2);
+  __ bnez(tmp1, error);

   BarrierSetAssembler::check_oop(masm, obj, tmp1, tmp2, error);
 }

fisk · 2023-02-08T10:42:40Z

@fisk : Hi, I think we should also add following changes for riscv to make it work:

diff --git a/src/hotspot/cpu/riscv/gc/shared/barrierSetAssembler_riscv.cpp b/src/hotspot/cpu/riscv/gc/shared/barrierSetAssembler_riscv.cpp
index ed53fbf22c8..662de44de29 100644
--- a/src/hotspot/cpu/riscv/gc/shared/barrierSetAssembler_riscv.cpp
+++ b/src/hotspot/cpu/riscv/gc/shared/barrierSetAssembler_riscv.cpp
@@ -316,8 +316,7 @@ void BarrierSetAssembler::check_oop(MacroAssembler* masm, Register obj, Register
   __ mv(tmp2, (intptr_t) Universe::verify_oop_bits());

   // Compare tmp1 and tmp2.
-  __ xorr(tmp1, tmp1, tmp2);
-  __ bnez(tmp1, error);
+  __ bne(tmp1, tmp2, error);

   // Make sure klass is 'reasonable', which is not zero.
   __ load_klass(obj, obj, tmp1); // get klass
diff --git a/src/hotspot/cpu/riscv/gc/z/zBarrierSetAssembler_riscv.cpp b/src/hotspot/cpu/riscv/gc/z/zBarrierSetAssembler_riscv.cpp
index 0741869ddaf..1ebfb8f9e23 100644
--- a/src/hotspot/cpu/riscv/gc/z/zBarrierSetAssembler_riscv.cpp
+++ b/src/hotspot/cpu/riscv/gc/z/zBarrierSetAssembler_riscv.cpp
@@ -449,10 +449,10 @@ void ZBarrierSetAssembler::generate_c1_load_barrier_runtime_stub(StubAssembler*

 void ZBarrierSetAssembler::check_oop(MacroAssembler* masm, Register obj, Register tmp1, Register tmp2, Label& error) {
   // Check if mask is good.
-  // verifies that ZAddressBadMask & x10 == 0
-  __ ld(c_rarg3, Address(xthread, ZThreadLocalData::address_bad_mask_offset()));
-  __ andr(c_rarg2, x10, c_rarg3);
-  __ bnez(c_rarg2, error);
+  // verifies that ZAddressBadMask & obj == 0
+  __ ld(tmp2, Address(xthread, ZThreadLocalData::address_bad_mask_offset()));
+  __ andr(tmp1, obj, tmp2);
+  __ bnez(tmp1, error);

   BarrierSetAssembler::check_oop(masm, obj, tmp1, tmp2, error);
 }

Fixed!

xmas92

lgtm.

xmas92 · 2023-02-09T13:09:29Z

src/hotspot/cpu/aarch64/gc/z/zBarrierSetAssembler_aarch64.cpp

+
+void ZBarrierSetAssembler::check_oop(MacroAssembler* masm, Register obj, Register tmp1, Register tmp2, Label& error) {
+  // Check if mask is good.
+  // verifies that ZAddressBadMask & r0 == 0


Update comment s/r0/obj

fisk · 2023-02-09T15:10:07Z

Thanks for the review @xmas92! Will fix the comment.

coleenp

This change looks nice. Did you run tier8 or tier1 tests with -XX:+VerifyOops? I thought we ran some general testing in tier3 with -XX:+VerifyOops but we don't seem to be doing that. Thanks.

openjdk · 2023-02-09T15:34:40Z

@fisk 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:

8300255: Introduce interface for GC oop verification in the assembler

Co-authored-by: Martin Doerr <mdoerr@openjdk.org>
Co-authored-by: Axel Boldt-Christmas <aboldtch@openjdk.org>
Co-authored-by: Yadong Wang <yadongwang@openjdk.org>
Reviewed-by: fyang, aboldtch, coleenp

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 72 new commits pushed to the master branch:

723433d: 8302117: IgnoreUnrecognizedVMOptions flag causes failure in ArchiveHeapTestClass
e245620: 8293198: [vectorapi] Improve the implementation of VectorMask.indexInRange()
b814cfc: 8178806: Better exception logging in crypto code
8c87a67: 8245654: Add Certigna Root CA
97d0c87: 8302109: Trivial fixes to btree tests
0aeebee: 8301988: VerifyLiveClosure::verify_liveness asserts on bad pointers outside heap
4815566: 8228604: StackMapFrames are missing from redefined class bytes of retransformed classes
5147969: 8272288: Funky multiresolution image breaks graphics context
77ead44: 8302066: Counter _number_of_nmethods_with_dependencies should be atomic.
f4b72df: 8282379: [LOOM] vmTestbase/nsk/jdi/ClassType/invokeMethod/invokemethod011 sometimes fails
... and 62 more: https://git.openjdk.org/jdk/compare/522fa1327422e49eaa172d43185b3d85b2561036...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.

RealFYang

Updated RISC-V part looks good. Thanks.

fisk · 2023-02-10T14:49:45Z

Updated RISC-V part looks good. Thanks.

Thanks!

fisk · 2023-02-10T14:52:41Z

This change looks nice. Did you run tier8 or tier1 tests with -XX:+VerifyOops? I thought we ran some general testing in tier3 with -XX:+VerifyOops but we don't seem to be doing that. Thanks.

Thanks for the review! I have run gc-test-suite locally on both an AArch64 machine and x86_64 machine, with -XX:+VerifyOops with ZGC and G1, and it looks fine. I think it exercises verify oops pretty well. Do you want me to run tier8 as well? Personally, I hesitate a bit to run off a tier8 job for this change if gc-test-suite is happy with -XX:+VerifyOops.

coleenp · 2023-02-10T15:40:59Z

Tier8 is unnecessary as you've done general testing with it.

fisk · 2023-02-10T16:30:44Z

Tier8 is unnecessary as you've done general testing with it.

Okay, thanks!

fisk · 2023-02-13T15:49:36Z

/integrate

openjdk · 2023-02-13T15:51:01Z

Going to push as commit f4d4fa5.
Since your change was applied there have been 105 commits pushed to the master branch:

99b6c0e: 8302289: RISC-V: Use bgez instruction in arraycopy_simple_check when possible
57aef85: 8301838: PPC: continuation yield intrinsic: exception check not needed if yield succeeded
df93880: 8301942: java/net/httpclient/DigestEchoClientSSL.java fail with -Xcomp
0025764: 8040793: vmTestbase/nsk/monitoring/stress/lowmem fails on calling isCollectionUsageThresholdExceeded()
1f9c110: 8301958: Reduce Arrays.copyOf/-Range overheads
cb81073: 8300139: [AIX] Use pthreads to avoid JNI_createVM call from primordial thread
bbd8ae7: 8294194: [AArch64] Create intrinsics compress and expand
4e327db: 8301499: Replace NULL with nullptr in cpu/zero
0458d38: 6513512: MetalLookAndFeel.initClassDefaults does not install an entry for MetalMenuBarUI
f4b140b: 8296410: HttpClient throws java.io.IOException: no statuscode in response for HTTP2
... and 95 more: https://git.openjdk.org/jdk/compare/522fa1327422e49eaa172d43185b3d85b2561036...master

Your commit was automatically rebased without conflicts.

openjdk · 2023-02-13T15:51:13Z

@fisk Pushed as commit f4d4fa5.

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

8300255: Introduce interface for GC oop verification in the assembler

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8300255: Introduce interface for GC oop verification in the assembler #12443

8300255: Introduce interface for GC oop verification in the assembler #12443

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		#define __ masm->

		void BarrierSetAssembler::check_oop(MacroAssembler* masm, Register obj, Register tmp1, Register tmp2, Label& error) {

8300255: Introduce interface for GC oop verification in the assembler #12443

8300255: Introduce interface for GC oop verification in the assembler #12443

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