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8329433: Reduce nmethod header size #18768

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a0c46b8
8329433: Reduce nmethod header size
vnkozlov Apr 12, 2024
488f1b9
Moved some fields initialization into init_defaults()
vnkozlov Apr 15, 2024
13744e7
Union fields which usages do not overlap
vnkozlov Apr 15, 2024
6cb22e8
Use 16-bits types for header_size and frame_complete_offset arguments
vnkozlov Apr 16, 2024
8405a23
Address comments. Used checked_cast.
vnkozlov Apr 16, 2024
71ade0f
Shuffle fields initialization
vnkozlov Apr 17, 2024
6a164b1
remove trailing space
vnkozlov Apr 17, 2024
adc1759
Merge master
vnkozlov Apr 17, 2024
5f5f30d
Address comment
vnkozlov Apr 17, 2024
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42 changes: 17 additions & 25 deletions src/hotspot/share/code/nmethod.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1230,25 +1230,21 @@ nmethod::nmethod(
_unwind_handler_offset = 0;
_gc_epoch = CodeCache::gc_epoch();

int skipped_insts_size = code_buffer->total_skipped_instructions_size();
#ifdef ASSERT
assert(((skipped_insts_size >> 16) == 0), "size is bigger than 64Kb: %d", skipped_insts_size);

// SECT_CONSTS is first in code buffer so the offset should be 0.
int consts_offset = code_buffer->total_offset_of(code_buffer->consts());
assert(consts_offset == 0, "const_offset: %d", consts_offset);
#endif
_skipped_instructions_size = (uint16_t)skipped_insts_size;

_stub_offset = content_offset() + code_buffer->total_offset_of(code_buffer->stubs());
_skipped_instructions_size = checked_cast<uint16_t>(code_buffer->total_skipped_instructions_size());

_stub_offset = content_offset() + code_buffer->total_offset_of(code_buffer->stubs());
#ifdef ASSERT
int oops_size = align_up(code_buffer->total_oop_size(), oopSize);
int metadata_size = align_up(code_buffer->total_metadata_size(), wordSize);
int sum_size = oops_size + metadata_size;
assert((sum_size >> 16) == 0, "data size is bigger than 64Kb: %d", sum_size);

_metadata_offset = (uint16_t)oops_size;
_dependencies_offset = _metadata_offset + (uint16_t)metadata_size;
#endif
_metadata_offset = checked_cast<uint16_t>(align_up(code_buffer->total_oop_size(), oopSize));
_dependencies_offset = _metadata_offset + checked_cast<uint16_t>(align_up(code_buffer->total_metadata_size(), wordSize));
_scopes_pcs_offset = _dependencies_offset;
_scopes_data_offset = _scopes_pcs_offset;
_handler_table_offset = _scopes_data_offset;
Expand All @@ -1264,8 +1260,8 @@ nmethod::nmethod(

_compile_id = compile_id;
_compiler_type = type;
_entry_offset = (uint16_t)offsets->value(CodeOffsets::Entry);
_verified_entry_offset = (uint16_t)offsets->value(CodeOffsets::Verified_Entry);
_entry_offset = checked_cast<uint16_t>(offsets->value(CodeOffsets::Entry));
_verified_entry_offset = checked_cast<uint16_t>(offsets->value(CodeOffsets::Verified_Entry));
_osr_entry_point = nullptr;
_pc_desc_container.reset_to(nullptr);

Expand Down Expand Up @@ -1382,15 +1378,11 @@ nmethod::nmethod(
_orig_pc_offset = orig_pc_offset;
_gc_epoch = CodeCache::gc_epoch();

int skipped_insts_size = code_buffer->total_skipped_instructions_size();
#ifdef ASSERT
assert(((skipped_insts_size >> 16) == 0), "size is bigger than 64Kb: %d", skipped_insts_size);

// SECT_CONSTS is first in code buffer so the offset should be 0.
int consts_offset = code_buffer->total_offset_of(code_buffer->consts());
assert(consts_offset == 0, "const_offset: %d", consts_offset);
#endif
_skipped_instructions_size = (uint16_t)skipped_insts_size;

_skipped_instructions_size = checked_cast<uint16_t>(code_buffer->total_skipped_instructions_size());

_stub_offset = content_offset() + code_buffer->total_offset_of(code_buffer->stubs());
set_ctable_begin(header_begin() + content_offset());
Expand Down Expand Up @@ -1433,16 +1425,16 @@ nmethod::nmethod(
} else {
_unwind_handler_offset = -1;
}

#ifdef ASSERT
int oops_size = align_up(code_buffer->total_oop_size(), oopSize);
int metadata_size = align_up(code_buffer->total_metadata_size(), wordSize);
int deps_size = align_up((int)dependencies->size_in_bytes(), oopSize);
int sum_size = oops_size + metadata_size + deps_size;
assert((sum_size >> 16) == 0, "data size is bigger than 64Kb: %d", sum_size);

_metadata_offset = (uint16_t)oops_size;
_dependencies_offset = _metadata_offset + (uint16_t)metadata_size;
_scopes_pcs_offset = _dependencies_offset + (uint16_t)deps_size;
#endif
_metadata_offset = checked_cast<uint16_t>(align_up(code_buffer->total_oop_size(), oopSize));
_dependencies_offset = _metadata_offset + checked_cast<uint16_t>(align_up(code_buffer->total_metadata_size(), wordSize));
_scopes_pcs_offset = _dependencies_offset + checked_cast<uint16_t>(align_up((int)dependencies->size_in_bytes(), oopSize));
_scopes_data_offset = _scopes_pcs_offset + adjust_pcs_size(debug_info->pcs_size());
_handler_table_offset = _scopes_data_offset + align_up(debug_info->data_size (), oopSize);
_nul_chk_table_offset = _handler_table_offset + align_up(handler_table->size_in_bytes(), oopSize);
Expand All @@ -1456,8 +1448,8 @@ nmethod::nmethod(
#endif
assert((data_offset() + data_end_offset) <= nmethod_size, "wrong nmethod's size: %d < %d", nmethod_size, (data_offset() + data_end_offset));

_entry_offset = (uint16_t)offsets->value(CodeOffsets::Entry);
_verified_entry_offset = (uint16_t)offsets->value(CodeOffsets::Verified_Entry);
_entry_offset = checked_cast<uint16_t>(offsets->value(CodeOffsets::Entry));
_verified_entry_offset = checked_cast<uint16_t>(offsets->value(CodeOffsets::Verified_Entry));
_osr_entry_point = code_begin() + offsets->value(CodeOffsets::OSR_Entry);

_pc_desc_container.reset_to(scopes_pcs_begin());
Expand Down
2 changes: 2 additions & 0 deletions src/hotspot/share/code/nmethod.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -966,9 +966,11 @@ class nmethod : public CodeBlob {

// JVMTI's GetLocalInstance() support
ByteSize native_receiver_sp_offset() {
assert(is_native_method(), "sanity");
return _native_receiver_sp_offset;
}
ByteSize native_basic_lock_sp_offset() {
assert(is_native_method(), "sanity");
return _native_basic_lock_sp_offset;
}

Expand Down
5 changes: 2 additions & 3 deletions src/hotspot/share/memory/heap.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -54,13 +54,12 @@ class HeapBlock {
void initialize(size_t length) { set_length(length); set_used(); }
// Merging/splitting
void set_length(size_t length) {
LP64_ONLY( assert(((length >> 32) == 0), "sanity"); )
_header._length = (uint32_t)length;
_header._length = checked_cast<uint32_t>(length);
}

// Accessors
void* allocated_space() const { return (void*)(this + 1); }
size_t length() const { return (size_t)_header._length; }
size_t length() const { return _header._length; }

// Used/free
void set_used() { _header._used = true; }
Expand Down