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8380129: Remove AccessFlags::print_on in favor of context-specific printing #30746

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8380129: Remove AccessFlags::print_on in favor of context-specific printing #30746

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9ac3afc
removed accessflags::print_on and lifted to separate printers
caspernorrbin Apr 15, 2026
f471984
feedback fixes
caspernorrbin Apr 16, 2026
71b7c76
reorder private/public/protected in instanceklass
caspernorrbin Apr 17, 2026
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17 changes: 15 additions & 2 deletions src/hotspot/share/oops/instanceKlass.cpp
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Expand Up @@ -3702,13 +3702,26 @@ const char* InstanceKlass::init_state_name() const {
return state_names[init_state()];
}

#if !defined(PRODUCT) || INCLUDE_JVMTI
void InstanceKlass::print_class_flags(outputStream* st) const {
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@dholmes-ora dholmes-ora Apr 16, 2026

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This is incomplete. If the class is an inner class then additional access flags are possible (private, protected, static).
EDIT: Hmm jvm_constants.h does not recognise this either via JVM_RECOGNIZED_CLASS_MODIFIERS. Not sure how this should be handled.

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@dholmes-ora dholmes-ora Apr 16, 2026

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Also do we need to handle ACC_MODULE, or do we not actually create an instanceKlass for those?

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@liach liach Apr 16, 2026

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On jdk side we never have Class for modules. These classfiles are exclusively handled by Java code in ModuleDescriptor I think?

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@caspernorrbin caspernorrbin Apr 16, 2026

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I have now changed it to use compute_modifier_flags() instead of access_flags() directly. With this, we get member-class modifiers printed. I expanded the test which shows that private/protected static gets printed. This matches the class' modifiers, which feels like the correct behavior.

ACC_MODULE is not needed here because it never becomes an InstanceKlass. It is rejected as a normal class during parsing.

AccessFlags flags = access_flags();
if (flags.is_public ()) st->print("public ");
if (flags.is_final ()) st->print("final ");
if (flags.is_interface ()) st->print("interface ");
if (flags.is_abstract ()) st->print("abstract ");
if (flags.is_annotation()) st->print("annotation ");
if (flags.is_enum ()) st->print("enum ");
if (flags.is_synthetic ()) st->print("synthetic ");
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@liach liach Apr 26, 2026

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The bit for SYNTHETIC, 0x1000, comes before ANNOTATION, 0x2000, and ENUM, 0x4000. That should be tracked in a separate issue though.

}
#endif // !defined(PRODUCT) || INCLUDE_JVMTI

void InstanceKlass::print_on(outputStream* st) const {
assert(is_klass(), "must be klass");
Klass::print_on(st);

st->print(BULLET"instance size: %d", size_helper()); st->cr();
st->print(BULLET"klass size: %d", size()); st->cr();
st->print(BULLET"access: "); access_flags().print_on(st); st->cr();
st->print(BULLET"access: "); print_class_flags(st); st->cr();
st->print(BULLET"flags: "); _misc_flags.print_on(st); st->cr();
st->print(BULLET"state: "); st->print_cr("%s", init_state_name());
st->print(BULLET"name: "); name()->print_value_on(st); st->cr();
Expand Down Expand Up @@ -3848,7 +3861,7 @@ void InstanceKlass::print_on(outputStream* st) const {

void InstanceKlass::print_value_on(outputStream* st) const {
assert(is_klass(), "must be klass");
if (Verbose || WizardMode) access_flags().print_on(st);
if (Verbose || WizardMode) print_class_flags(st);
name()->print_value_on(st);
}

Expand Down
5 changes: 5 additions & 0 deletions src/hotspot/share/oops/instanceKlass.hpp
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Expand Up @@ -1169,6 +1169,11 @@ class InstanceKlass: public Klass {
// Printing
void print_on(outputStream* st) const override;
void print_value_on(outputStream* st) const override;
#if !defined(PRODUCT) || INCLUDE_JVMTI
void print_class_flags(outputStream* st) const;
#else
void print_class_flags(outputStream* st) const PRODUCT_RETURN;
#endif

void oop_print_value_on(oop obj, outputStream* st) override;

Expand Down
6 changes: 3 additions & 3 deletions src/hotspot/share/oops/klassVtable.cpp
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@@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand Down Expand Up @@ -1066,7 +1066,7 @@ void klassVtable::dump_vtable() {
Method* m = unchecked_method_at(i);
if (m != nullptr) {
tty->print(" (%5d) ", i);
m->access_flags().print_on(tty);
m->print_access_flags(tty);
if (m->is_default_method()) {
tty->print("default ");
}
Expand Down Expand Up @@ -1421,7 +1421,7 @@ void klassItable::dump_itable() {
Method* m = ime->method();
if (m != nullptr) {
tty->print(" (%5d) ", i);
m->access_flags().print_on(tty);
m->print_access_flags(tty);
if (m->is_default_method()) {
tty->print("default ");
}
Expand Down
24 changes: 21 additions & 3 deletions src/hotspot/share/oops/method.cpp
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Expand Up @@ -2204,7 +2204,7 @@ void Method::print_on(outputStream* st) const {
st->print (" - method holder: "); method_holder()->print_value_on(st); st->cr();
st->print (" - constants: " PTR_FORMAT " ", p2i(constants()));
constants()->print_value_on(st); st->cr();
st->print (" - access: 0x%x ", access_flags().as_method_flags()); access_flags().print_on(st); st->cr();
st->print (" - access: 0x%x ", access_flags().as_method_flags()); print_access_flags(st); st->cr();
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@dholmes-ora dholmes-ora Apr 16, 2026

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There is an existing inconsistency here in that we print the raw flags as "method flags" only but then we print them all. Your new code implicitly filters the flags by only printing the expected method flags.

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@caspernorrbin caspernorrbin Apr 16, 2026

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as_method_flags() asserts that only recognized method modifiers are set, so these are not arbitrary raw flags. Previously, the generic printer could misinterpret overlapping bits, whereas the new method-specific printer prints them correctly. This looks like the right behavior to me.

st->print (" - flags: 0x%x ", _flags.as_int()); _flags.print_on(st); st->cr();
st->print (" - name: "); name()->print_value_on(st); st->cr();
st->print (" - signature: "); signature()->print_value_on(st); st->cr();
Expand Down Expand Up @@ -2278,8 +2278,8 @@ void Method::print_on(outputStream* st) const {
}
}

void Method::print_linkage_flags(outputStream* st) {
access_flags().print_on(st);
void Method::print_linkage_flags(outputStream* st) const {
print_access_flags(st);
if (is_default_method()) {
st->print("default ");
}
Expand All @@ -2289,6 +2289,24 @@ void Method::print_linkage_flags(outputStream* st) {
}
#endif //PRODUCT

#if !defined(PRODUCT) || INCLUDE_JVMTI
void Method::print_access_flags(outputStream* st) const {
AccessFlags flags = access_flags();
if (flags.is_public ()) st->print("public ");
if (flags.is_private ()) st->print("private ");
if (flags.is_protected ()) st->print("protected ");
if (flags.is_static ()) st->print("static ");
if (flags.is_final ()) st->print("final ");
if (flags.is_synchronized ()) st->print("synchronized ");
if (flags.is_bridge ()) st->print("bridge ");
if (flags.has_vararg ()) st->print("varargs ");
if (flags.is_native ()) st->print("native ");
if (flags.is_abstract ()) st->print("abstract ");
if (flags.is_strict_method()) st->print("strict ");
if (flags.is_synthetic ()) st->print("synthetic ");
}
#endif // !defined(PRODUCT) || INCLUDE_JVMTI

void Method::print_value_on(outputStream* st) const {
assert(is_method(), "must be method");
st->print("%s", internal_name());
Expand Down
7 changes: 6 additions & 1 deletion src/hotspot/share/oops/method.hpp
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Expand Up @@ -859,7 +859,12 @@ class Method : public Metadata {
void print_on(outputStream* st) const;
#endif
void print_value_on(outputStream* st) const;
void print_linkage_flags(outputStream* st) PRODUCT_RETURN;
#if !defined(PRODUCT) || INCLUDE_JVMTI
void print_access_flags(outputStream* st) const;
#else
void print_access_flags(outputStream* st) const PRODUCT_RETURN;
#endif
void print_linkage_flags(outputStream* st) const PRODUCT_RETURN;

const char* internal_name() const { return "{method}"; }

Expand Down
14 changes: 7 additions & 7 deletions src/hotspot/share/prims/jvmtiRedefineClasses.cpp
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@@ -1,5 +1,5 @@
/*
* Copyright (c) 2003, 2025, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2003, 2026, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand Down Expand Up @@ -4544,7 +4544,7 @@ void VM_RedefineClasses::dump_methods() {
LogStreamHandle(Trace, redefine, class, dump) log_stream;
Method* m = _old_methods->at(j);
log_stream.print("%4d (%5d) ", j, m->vtable_index());
m->access_flags().print_on(&log_stream);
m->print_access_flags(&log_stream);
log_stream.print(" -- ");
m->print_name(&log_stream);
log_stream.cr();
Expand All @@ -4554,7 +4554,7 @@ void VM_RedefineClasses::dump_methods() {
LogStreamHandle(Trace, redefine, class, dump) log_stream;
Method* m = _new_methods->at(j);
log_stream.print("%4d (%5d) ", j, m->vtable_index());
m->access_flags().print_on(&log_stream);
m->print_access_flags(&log_stream);
log_stream.print(" -- ");
m->print_name(&log_stream);
log_stream.cr();
Expand All @@ -4564,22 +4564,22 @@ void VM_RedefineClasses::dump_methods() {
LogStreamHandle(Trace, redefine, class, dump) log_stream;
Method* m = _matching_old_methods[j];
log_stream.print("%4d (%5d) ", j, m->vtable_index());
m->access_flags().print_on(&log_stream);
m->print_access_flags(&log_stream);
log_stream.print(" -- ");
m->print_name();
log_stream.cr();

m = _matching_new_methods[j];
log_stream.print(" (%5d) ", m->vtable_index());
m->access_flags().print_on(&log_stream);
m->print_access_flags(&log_stream);
log_stream.cr();
}
log_trace(redefine, class, dump)("_deleted_methods --");
for (j = 0; j < _deleted_methods_length; ++j) {
LogStreamHandle(Trace, redefine, class, dump) log_stream;
Method* m = _deleted_methods[j];
log_stream.print("%4d (%5d) ", j, m->vtable_index());
m->access_flags().print_on(&log_stream);
m->print_access_flags(&log_stream);
log_stream.print(" -- ");
m->print_name(&log_stream);
log_stream.cr();
Expand All @@ -4589,7 +4589,7 @@ void VM_RedefineClasses::dump_methods() {
LogStreamHandle(Trace, redefine, class, dump) log_stream;
Method* m = _added_methods[j];
log_stream.print("%4d (%5d) ", j, m->vtable_index());
m->access_flags().print_on(&log_stream);
m->print_access_flags(&log_stream);
log_stream.print(" -- ");
m->print_name(&log_stream);
log_stream.cr();
Expand Down
4 changes: 2 additions & 2 deletions src/hotspot/share/prims/methodHandles.cpp
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Expand Up @@ -267,7 +267,7 @@ oop MethodHandles::init_method_MemberName(Handle mname, CallInfo& info) {
ls.print_cr("memberName: invokeinterface method_holder::method: %s, itableindex: %d, access_flags:",
Method::name_and_sig_as_C_string(m->method_holder(), m->name(), m->signature()),
vmindex);
m->access_flags().print_on(&ls);
m->print_access_flags(&ls);
if (!m->is_abstract()) {
if (!m->is_private()) {
ls.print("default");
Expand Down Expand Up @@ -314,7 +314,7 @@ oop MethodHandles::init_method_MemberName(Handle mname, CallInfo& info) {
ls.print_cr("memberName: invokevirtual method_holder::method: %s, receiver: %s, vtableindex: %d, access_flags:",
Method::name_and_sig_as_C_string(m->method_holder(), m->name(), m->signature()),
m_klass->internal_name(), vmindex);
m->access_flags().print_on(&ls);
m->print_access_flags(&ls);
if (m->is_default_method()) {
ls.print("default");
}
Expand Down
19 changes: 17 additions & 2 deletions src/hotspot/share/runtime/fieldDescriptor.cpp
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@@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand Down Expand Up @@ -108,8 +108,23 @@ void fieldDescriptor::reinitialize(InstanceKlass* ik, const FieldInfo& fieldinfo
guarantee(_fieldinfo.name_index() != 0 && _fieldinfo.signature_index() != 0, "bad constant pool index for fieldDescriptor");
}

#if !defined(PRODUCT) || INCLUDE_JVMTI
void fieldDescriptor::print_access_flags(outputStream* st) const {
AccessFlags flags = access_flags();
if (flags.is_public ()) st->print("public ");
if (flags.is_private ()) st->print("private ");
if (flags.is_protected()) st->print("protected ");
if (flags.is_static ()) st->print("static ");
if (flags.is_final ()) st->print("final ");
if (flags.is_volatile ()) st->print("volatile ");
if (flags.is_transient()) st->print("transient ");
if (flags.is_enum ()) st->print("enum ");
if (flags.is_synthetic()) st->print("synthetic ");
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@liach liach Apr 26, 2026

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Same SYNTHETIC remark here.

}
#endif // !defined(PRODUCT) || INCLUDE_JVMTI

void fieldDescriptor::print_on(outputStream* st) const {
access_flags().print_on(st);
print_access_flags(st);
if (field_flags().is_injected()) st->print("injected ");
name()->print_value_on(st);
st->print(" ");
Expand Down
7 changes: 6 additions & 1 deletion src/hotspot/share/runtime/fieldDescriptor.hpp
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand Down Expand Up @@ -111,6 +111,11 @@ class fieldDescriptor {
void print() const;
void print_on(outputStream* st) const;
void print_on_for(outputStream* st, oop obj);
#if !defined(PRODUCT) || INCLUDE_JVMTI
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@liach liach Apr 15, 2026

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The new !defined(PRODUCT) seems to be only for the gtest. I wonder if gtest can run the test for print_access_flags based on INCLUDE_JVMTI flag instead; the macro condition tweak seems weird.

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@dholmes-ora dholmes-ora Apr 16, 2026

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I am surprised that we only ever print access flags in relation to JVMTI - I would have expected logging or crash reporting to do so. In any case I also find the !PRODUCT a little jarring. Given we always have JVMTI it makes no different to our binaries.

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@caspernorrbin caspernorrbin Apr 16, 2026

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After some thought, I have removed all the #if guards on the printers. To me, these are now ordinary printing utilities belonging to either Method, InstanceKlass, or fieldDescriptor. They are not directly tied to JVMTI, so should not be guarded by it. Let me know if you agree.

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@dholmes-ora dholmes-ora Apr 17, 2026

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That is fine with me.

void print_access_flags(outputStream* st) const;
#else
void print_access_flags(outputStream* st) const PRODUCT_RETURN;
#endif
};

#endif // SHARE_RUNTIME_FIELDDESCRIPTOR_HPP
23 changes: 1 addition & 22 deletions src/hotspot/share/utilities/accessFlags.cpp
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand All @@ -22,29 +22,8 @@
*
*/

#include "oops/oop.inline.hpp"
#include "runtime/atomicAccess.hpp"
#include "utilities/accessFlags.hpp"

#if !defined(PRODUCT) || INCLUDE_JVMTI

void AccessFlags::print_on(outputStream* st) const {
if (is_public ()) st->print("public " );
if (is_private ()) st->print("private " );
if (is_protected ()) st->print("protected " );
if (is_static ()) st->print("static " );
if (is_final ()) st->print("final " );
if (is_synchronized()) st->print("synchronized ");
if (is_volatile ()) st->print("volatile " );
if (is_transient ()) st->print("transient " );
if (is_native ()) st->print("native " );
if (is_interface ()) st->print("interface " );
if (is_abstract ()) st->print("abstract " );
if (is_synthetic ()) st->print("synthetic " );
}

#endif // !PRODUCT || INCLUDE_JVMTI

void accessFlags_init() {
assert(sizeof(AccessFlags) == sizeof(u2), "just checking size of flags");
}
14 changes: 6 additions & 8 deletions src/hotspot/share/utilities/accessFlags.hpp
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
Expand Down Expand Up @@ -53,10 +53,15 @@ class AccessFlags {
bool is_synchronized() const { return (_flags & JVM_ACC_SYNCHRONIZED) != 0; }
bool is_super () const { return (_flags & JVM_ACC_SUPER ) != 0; }
bool is_volatile () const { return (_flags & JVM_ACC_VOLATILE ) != 0; }
bool is_bridge () const { return (_flags & JVM_ACC_BRIDGE ) != 0; }
bool is_transient () const { return (_flags & JVM_ACC_TRANSIENT ) != 0; }
bool has_vararg () const { return (_flags & JVM_ACC_VARARGS ) != 0; }
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@liach liach Apr 15, 2026

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I recommend is_varargs, this flag is not enforced by the VM so technically users can create class files that declare varargs methods without a trailing array argument.

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@dholmes-ora dholmes-ora Apr 16, 2026

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+1

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@caspernorrbin caspernorrbin Apr 16, 2026

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I renamed it to is_varargs. I originally picked has_varargs because that is the name on the valhalla branch, but I am fine with this too.

bool is_native () const { return (_flags & JVM_ACC_NATIVE ) != 0; }
bool is_enum () const { return (_flags & JVM_ACC_ENUM ) != 0; }
bool is_annotation () const { return (_flags & JVM_ACC_ANNOTATION ) != 0; }
bool is_interface () const { return (_flags & JVM_ACC_INTERFACE ) != 0; }
bool is_abstract () const { return (_flags & JVM_ACC_ABSTRACT ) != 0; }
bool is_strict_method() const { return (_flags & JVM_ACC_STRICT ) != 0; }
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@liach liach Apr 15, 2026

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If "strict method" sounds too weird, we can call this "strictfp" following the original Java language modifier's name.

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@dholmes-ora dholmes-ora Apr 16, 2026

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This will be short-lived either way as valhalla gets rid of the legacy strictfp notion for methods anyway.

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@caspernorrbin caspernorrbin Apr 16, 2026

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Renamed to is_strictfp instead.


// Attribute flags
bool is_synthetic () const { return (_flags & JVM_ACC_SYNTHETIC ) != 0; }
Expand Down Expand Up @@ -92,13 +97,6 @@ class AccessFlags {
assert((_flags & JVM_RECOGNIZED_CLASS_MODIFIERS) == _flags, "only recognized flags");
return _flags;
}

// Printing/debugging
#if INCLUDE_JVMTI
void print_on(outputStream* st) const;
#else
void print_on(outputStream* st) const PRODUCT_RETURN;
#endif
};

inline AccessFlags accessFlags_from(u2 flags) {
Expand Down
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