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8356075: Support Shenandoah GC in JVMCI #25001

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344955a
Graal Shenandoah support
rkennke Apr 2, 2025
956bbec
Revert "8321373: Build should use LC_ALL=C.UTF-8"
rkennke Apr 9, 2025
0bcdb7d
Support for Shenandoah card-table barriers in JVMCI
rkennke Apr 17, 2025
2f54728
Merge branch 'master' into graal-shenandoah-support
rkennke Apr 30, 2025
f54cb48
Revert unrelated changes
rkennke May 2, 2025
1543e8f
Revert unrelated changes
rkennke May 2, 2025
25a8a6f
Remove unnecessary stuff
rkennke May 2, 2025
6487a9f
Fix ordering of includes
rkennke May 2, 2025
c95313a
Initialize cardtable_start_address to nullptr
rkennke May 5, 2025
4434458
Align backslashes
rkennke May 5, 2025
41084f3
Simplify pre-barrier runtime entry
rkennke May 5, 2025
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6 changes: 6 additions & 0 deletions src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,9 @@
#include "utilities/events.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/powerOfTwo.hpp"
#if INCLUDE_JVMCI
#include "jvmci/jvmci.hpp"
#endif
#if INCLUDE_JFR
#include "gc/shenandoah/shenandoahJfrSupport.hpp"
#endif
Expand Down Expand Up @@ -2233,6 +2236,9 @@ void ShenandoahHeap::stw_unload_classes(bool full_gc) {
ShenandoahGCWorkerPhase worker_phase(phase);
bool unloading_occurred = SystemDictionary::do_unloading(gc_timer());

// Clean JVMCI metadata handles.
JVMCI_ONLY(JVMCI::do_unloading(unloading_occurred));

uint num_workers = _workers->active_workers();
ShenandoahClassUnloadingTask unlink_task(phase, num_workers, unloading_occurred);
_workers->run_task(&unlink_task);
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3 changes: 3 additions & 0 deletions src/hotspot/share/gc/shenandoah/shenandoahRuntime.hpp
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Expand Up @@ -37,6 +37,9 @@ class ShenandoahRuntime : public AllStatic {
static void arraycopy_barrier_narrow_oop(narrowOop* src, narrowOop* dst, size_t length);

static void write_ref_field_pre(oopDesc* orig, JavaThread* thread);
static void pre_barrier(JavaThread* thread, oopDesc* orig) {
write_ref_field_pre(orig, thread);
}
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So, why not export write_ref_field_pre, instead of introducing this new method? Style/cleanliness, or something else? I am asking, because every time we add a new stub here, we would need to record it in AOTCache tables for Leyden benefit.

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It's about the argument ordering. Graal expects the Thread* to be prependend, while other JITs call it with the Thread* appended. I guess we could change other JIT calls to also prepend the thread, or change the interface to not pass the Thread* at all. I chose to follow G1 and export both variants.

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@shipilev shipilev May 5, 2025 •
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Oh, so this matches JVMCIRuntime::write_barrier_pre for G1 (weird place to have it, but oh well).

Does Graal need the Thread* argument?

I think this method is only called when SATB buffer is full. So the performance of this method is likely not affected by getting the current thread down in caller. So I think it would be more straight-forward to sharpen ShenandoahRuntime::write_ref_field_pre by dropping Thread* and then exporting that. Maybe also under the SR::write_barrier_pre name to be even more consistent for everything else.

Maybe @JohnTortugo wants to clean up more mess in C2 related to this :)

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Graal does not need the Thread* argument, but the runtime code behind write_ref_pre() currently uses it. I agree, it does not look performance critical to pass it through. However, getting rid of it seems to blow the scope of this PR. I'd rather do this as a follow-up.

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Actually, I'd probably add the new entry for Graal without the Thread* argument now, and fix the others in a follow-up. Otherwise we need to deal with it on the Graal side again later once we change the entry points.

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OK, but that follow-up risks changing the JVMCI interface again? How about we introduce:

static void write_barrier_pre(oopDesc* pre_val) {
  write_ref_field_pre(pre_val, JavaThread::current());
}

...and then the follow-up purges the old write_ref_field_pre? The implementation might need to be in .cpp.


static oopDesc* load_reference_barrier_strong(oopDesc* src, oop* load_addr);
static oopDesc* load_reference_barrier_strong_narrow(oopDesc* src, narrowOop* load_addr);
Expand Down
4 changes: 4 additions & 0 deletions src/hotspot/share/jvmci/jvmciCompilerToVM.hpp
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Expand Up @@ -111,6 +111,10 @@ class CompilerToVM {
#if INCLUDE_ZGC
static int sizeof_ZStoreBarrierEntry;
#endif
#if INCLUDE_SHENANDOAHGC
static address shenandoah_in_cset_fast_test_addr;
static int shenandoah_region_size_bytes_shift;
#endif

#ifdef X86
static int L1_line_size;
Expand Down
18 changes: 18 additions & 0 deletions src/hotspot/share/jvmci/jvmciCompilerToVMInit.cpp
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Expand Up @@ -52,6 +52,10 @@
#include "runtime/sharedRuntime.hpp"
#include "runtime/stubRoutines.hpp"
#include "utilities/resourceHash.hpp"
#if INCLUDE_SHENANDOAHGC
#include "gc/shenandoah/shenandoahHeap.hpp"
#include "gc/shenandoah/shenandoahHeapRegion.hpp"
#endif

int CompilerToVM::Data::oopDesc_klass_offset_in_bytes;
int CompilerToVM::Data::arrayOopDesc_length_offset_in_bytes;
Expand Down Expand Up @@ -86,6 +90,11 @@ address CompilerToVM::Data::ZPointerVectorLoadBadMask_address;
address CompilerToVM::Data::ZPointerVectorStoreBadMask_address;
address CompilerToVM::Data::ZPointerVectorStoreGoodMask_address;

#if INCLUDE_SHENANDOAHGC
address CompilerToVM::Data::shenandoah_in_cset_fast_test_addr;
int CompilerToVM::Data::shenandoah_region_size_bytes_shift;
#endif

bool CompilerToVM::Data::continuations_enabled;

#ifdef AARCH64
Expand Down Expand Up @@ -227,12 +236,21 @@ void CompilerToVM::Data::initialize(JVMCI_TRAPS) {
assert(base != nullptr, "unexpected byte_map_base");
cardtable_start_address = base;
cardtable_shift = CardTable::card_shift();
} else if (bs->is_a(BarrierSet::ShenandoahBarrierSet)) {
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@dougxc dougxc May 6, 2025 •
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This change is causing a failure in mach5 tier 1:

[2025-05-06T11:34:44,742Z] /workspace/open/src/hotspot/share/jvmci/jvmciCompilerToVMInit.cpp:239:35: error: no member named 'ShenandoahBarrierSet' in 'BarrierSet'
[2025-05-06T11:34:44,742Z]   } else if (bs->is_a(BarrierSet::ShenandoahBarrierSet)) {
[2025-05-06T11:34:44,742Z]                       ~~~~~~~~~~~~^
[2025-05-06T11:34:45,729Z] 1 error generated.

I assume it's missing #if INCLUDE_SHENANDOAHGC.

https://bugs.openjdk.org/browse/JDK-8356265

cardtable_shift = CardTable::card_shift();
} else {
// No card mark barriers
cardtable_start_address = nullptr;
cardtable_shift = 0;
}

#if INCLUDE_SHENANDOAHGC
if (UseShenandoahGC) {
shenandoah_in_cset_fast_test_addr = ShenandoahHeap::in_cset_fast_test_addr();
shenandoah_region_size_bytes_shift = ShenandoahHeapRegion::region_size_bytes_shift_jint();
}
#endif

#ifdef X86
L1_line_size = VM_Version::L1_line_size();
#endif
Expand Down
2 changes: 1 addition & 1 deletion src/hotspot/share/jvmci/jvmci_globals.cpp
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Expand Up @@ -229,7 +229,7 @@ bool JVMCIGlobals::enable_jvmci_product_mode(JVMFlagOrigin origin, bool use_graa
}

bool JVMCIGlobals::gc_supports_jvmci() {
return UseSerialGC || UseParallelGC || UseG1GC || UseZGC || UseEpsilonGC;
return UseSerialGC || UseParallelGC || UseG1GC || UseZGC || UseShenandoahGC || UseEpsilonGC;
}

void JVMCIGlobals::check_jvmci_supported_gc() {
Expand Down
27 changes: 27 additions & 0 deletions src/hotspot/share/jvmci/vmStructs_jvmci.cpp
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Expand Up @@ -53,6 +53,10 @@
#include "gc/z/zBarrierSetRuntime.hpp"
#include "gc/z/zThreadLocalData.hpp"
#endif
#if INCLUDE_SHENANDOAHGC
#include "gc/shenandoah/shenandoahRuntime.hpp"
#include "gc/shenandoah/shenandoahThreadLocalData.hpp"
#endif

#define VM_STRUCTS(nonstatic_field, static_field, unchecked_nonstatic_field, volatile_nonstatic_field) \
static_field(CompilerToVM::Data, oopDesc_klass_offset_in_bytes, int) \
Expand Down Expand Up @@ -129,6 +133,8 @@
static_field(CompilerToVM::Data, sizeof_arrayOopDesc, int) \
static_field(CompilerToVM::Data, sizeof_BasicLock, int) \
ZGC_ONLY(static_field(CompilerToVM::Data, sizeof_ZStoreBarrierEntry, int)) \
SHENANDOAHGC_ONLY(static_field(CompilerToVM::Data, shenandoah_in_cset_fast_test_addr, address)) \
SHENANDOAHGC_ONLY(static_field(CompilerToVM::Data, shenandoah_region_size_bytes_shift,int)) \
\
static_field(CompilerToVM::Data, dsin, address) \
static_field(CompilerToVM::Data, dcos, address) \
Expand Down Expand Up @@ -895,6 +901,13 @@
declare_function(JVMCIRuntime::load_and_clear_exception) \
G1GC_ONLY(declare_function(JVMCIRuntime::write_barrier_pre)) \
G1GC_ONLY(declare_function(JVMCIRuntime::write_barrier_post)) \
SHENANDOAHGC_ONLY(declare_function(ShenandoahRuntime::load_reference_barrier_strong)) \
SHENANDOAHGC_ONLY(declare_function(ShenandoahRuntime::load_reference_barrier_strong_narrow)) \
SHENANDOAHGC_ONLY(declare_function(ShenandoahRuntime::load_reference_barrier_weak)) \
SHENANDOAHGC_ONLY(declare_function(ShenandoahRuntime::load_reference_barrier_weak_narrow)) \
SHENANDOAHGC_ONLY(declare_function(ShenandoahRuntime::load_reference_barrier_phantom)) \
SHENANDOAHGC_ONLY(declare_function(ShenandoahRuntime::load_reference_barrier_phantom_narrow)) \
SHENANDOAHGC_ONLY(declare_function(ShenandoahRuntime::pre_barrier)) \
declare_function(JVMCIRuntime::validate_object) \
\
declare_function(JVMCIRuntime::test_deoptimize_call_int)
Expand Down Expand Up @@ -941,6 +954,15 @@

#endif // INCLUDE_ZGC

#if INCLUDE_SHENANDOAHGC

#define VM_INT_CONSTANTS_JVMCI_SHENANDOAH(declare_constant, declare_constant_with_value, declare_preprocessor_constant) \
declare_constant_with_value("ShenandoahThreadLocalData::gc_state_offset", in_bytes(ShenandoahThreadLocalData::gc_state_offset())) \
declare_constant_with_value("ShenandoahThreadLocalData::satb_mark_queue_index_offset", in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset())) \
declare_constant_with_value("ShenandoahThreadLocalData::satb_mark_queue_buffer_offset", in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset())) \
declare_constant_with_value("ShenandoahThreadLocalData::card_table_offset", in_bytes(ShenandoahThreadLocalData::card_table_offset())) \

#endif

#ifdef LINUX

Expand Down Expand Up @@ -1063,6 +1085,11 @@ VMIntConstantEntry JVMCIVMStructs::localHotSpotVMIntConstants[] = {
GENERATE_VM_INT_CONSTANT_WITH_VALUE_ENTRY,
GENERATE_PREPROCESSOR_VM_INT_CONSTANT_ENTRY)
#endif
#if INCLUDE_SHENANDOAHGC
VM_INT_CONSTANTS_JVMCI_SHENANDOAH(GENERATE_VM_INT_CONSTANT_ENTRY,
GENERATE_VM_INT_CONSTANT_WITH_VALUE_ENTRY,
GENERATE_PREPROCESSOR_VM_INT_CONSTANT_ENTRY)
#endif
#ifdef VM_INT_CPU_FEATURE_CONSTANTS
VM_INT_CPU_FEATURE_CONSTANTS
#endif
Expand Down