8288477: nmethod header size reduction

Reviewed-by: kvn, never

Author: Boris Ulasevich

src/hotspot/share/ci/ciEnv.cpp

@@ -1148,7 +1148,7 @@ void ciEnv::register_method(ciMethod* target,
                                debug_info(), dependencies(), code_buffer,
                                frame_words, oop_map_set,
                                handler_table, inc_table,
-                               compiler, task()->comp_level());
+                               compiler, CompLevel(task()->comp_level()));
 
     // Free codeBlobs
     code_buffer->free_blob();

src/hotspot/share/code/codeBlob.cpp

@@ -79,22 +79,22 @@ unsigned int CodeBlob::allocation_size(CodeBuffer* cb, int header_size) {
 }
 
 CodeBlob::CodeBlob(const char* name, CompilerType type, const CodeBlobLayout& layout, int frame_complete_offset, int frame_size, ImmutableOopMapSet* oop_maps, bool caller_must_gc_arguments, bool compiled) :
-  _type(type),
-  _size(layout.size()),
-  _header_size(layout.header_size()),
-  _frame_complete_offset(frame_complete_offset),
-  _data_offset(layout.data_offset()),
-  _frame_size(frame_size),
   _code_begin(layout.code_begin()),
   _code_end(layout.code_end()),
   _content_begin(layout.content_begin()),
   _data_end(layout.data_end()),
   _relocation_begin(layout.relocation_begin()),
   _relocation_end(layout.relocation_end()),
   _oop_maps(oop_maps),
+  _name(name),
+  _size(layout.size()),
+  _header_size(layout.header_size()),
+  _frame_complete_offset(frame_complete_offset),
+  _data_offset(layout.data_offset()),
+  _frame_size(frame_size),
   _caller_must_gc_arguments(caller_must_gc_arguments),
   _is_compiled(compiled),
-  _name(name)
+  _type(type)
 {
   assert(is_aligned(layout.size(),            oopSize), "unaligned size");
   assert(is_aligned(layout.header_size(),     oopSize), "unaligned size");
@@ -108,21 +108,21 @@ CodeBlob::CodeBlob(const char* name, CompilerType type, const CodeBlobLayout& la
 }
 
 CodeBlob::CodeBlob(const char* name, CompilerType type, const CodeBlobLayout& layout, CodeBuffer* cb /*UNUSED*/, int frame_complete_offset, int frame_size, OopMapSet* oop_maps, bool caller_must_gc_arguments, bool compiled) :
-  _type(type),
-  _size(layout.size()),
-  _header_size(layout.header_size()),
-  _frame_complete_offset(frame_complete_offset),
-  _data_offset(layout.data_offset()),
-  _frame_size(frame_size),
   _code_begin(layout.code_begin()),
   _code_end(layout.code_end()),
   _content_begin(layout.content_begin()),
   _data_end(layout.data_end()),
   _relocation_begin(layout.relocation_begin()),
   _relocation_end(layout.relocation_end()),
+  _name(name),
+  _size(layout.size()),
+  _header_size(layout.header_size()),
+  _frame_complete_offset(frame_complete_offset),
+  _data_offset(layout.data_offset()),
+  _frame_size(frame_size),
   _caller_must_gc_arguments(caller_must_gc_arguments),
   _is_compiled(compiled),
-  _name(name)
+  _type(type)
 {
   assert(is_aligned(_size,        oopSize), "unaligned size");
   assert(is_aligned(_header_size, oopSize), "unaligned size");

src/hotspot/share/code/codeBlob.hpp

@@ -90,16 +90,7 @@ class CodeBlob {
 
 protected:
 
-  const CompilerType _type;                      // CompilerType
-  int        _size;                              // total size of CodeBlob in bytes
-  int        _header_size;                       // size of header (depends on subclass)
-  int        _frame_complete_offset;             // instruction offsets in [0.._frame_complete_offset) have
-                                                 // not finished setting up their frame. Beware of pc's in
-                                                 // that range. There is a similar range(s) on returns
-                                                 // which we don't detect.
-  int        _data_offset;                       // offset to where data region begins
-  int        _frame_size;                        // size of stack frame
-
+  // order fields from large to small to minimize padding between fields
   address    _code_begin;
   address    _code_end;
   address    _content_begin;                     // address to where content region begins (this includes consts, insts, stubs)
@@ -109,13 +100,24 @@ class CodeBlob {
   address    _relocation_end;
 
   ImmutableOopMapSet* _oop_maps;                 // OopMap for this CodeBlob
-  bool                _caller_must_gc_arguments;
-
-  bool                _is_compiled;
 
   const char*         _name;
   S390_ONLY(int       _ctable_offset;)
 
+  int        _size;                              // total size of CodeBlob in bytes
+  int        _header_size;                       // size of header (depends on subclass)
+  int        _frame_complete_offset;             // instruction offsets in [0.._frame_complete_offset) have
+                                                 // not finished setting up their frame. Beware of pc's in
+                                                 // that range. There is a similar range(s) on returns
+                                                 // which we don't detect.
+  int        _data_offset;                       // offset to where data region begins
+  int        _frame_size;                        // size of stack frame
+
+  bool                _caller_must_gc_arguments;
+
+  bool                _is_compiled;
+  const CompilerType  _type;                     // CompilerType
+
 #ifndef PRODUCT
   AsmRemarks _asm_remarks;
   DbgStrings _dbg_strings;

src/hotspot/share/code/nmethod.cpp

@@ -511,7 +511,7 @@ nmethod* nmethod::new_nmethod(const methodHandle& method,
   ExceptionHandlerTable* handler_table,
   ImplicitExceptionTable* nul_chk_table,
   AbstractCompiler* compiler,
-  int comp_level
+  CompLevel comp_level
 #if INCLUDE_JVMCI
   , char* speculations,
   int speculations_len,
@@ -611,9 +611,9 @@ nmethod::nmethod(
   ByteSize basic_lock_sp_offset,
   OopMapSet* oop_maps )
   : CompiledMethod(method, "native nmethod", type, nmethod_size, sizeof(nmethod), code_buffer, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps, false, true),
-  _is_unloading_state(0),
   _native_receiver_sp_offset(basic_lock_owner_sp_offset),
-  _native_basic_lock_sp_offset(basic_lock_sp_offset)
+  _native_basic_lock_sp_offset(basic_lock_sp_offset),
+  _is_unloading_state(0)
 {
   {
     int scopes_data_offset   = 0;
@@ -624,6 +624,7 @@ nmethod::nmethod(
     assert_locked_or_safepoint(CodeCache_lock);
 
     init_defaults();
+    _comp_level              = CompLevel_none;
     _entry_bci               = InvocationEntryBci;
     // We have no exception handler or deopt handler make the
     // values something that will never match a pc like the nmethod vtable entry
@@ -648,7 +649,6 @@ nmethod::nmethod(
     _nmethod_end_offset      = _nul_chk_table_offset;
 #endif
     _compile_id              = compile_id;
-    _comp_level              = CompLevel_none;
     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);
     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);
     _osr_entry_point         = NULL;
@@ -738,17 +738,17 @@ nmethod::nmethod(
   ExceptionHandlerTable* handler_table,
   ImplicitExceptionTable* nul_chk_table,
   AbstractCompiler* compiler,
-  int comp_level
+  CompLevel comp_level
 #if INCLUDE_JVMCI
   , char* speculations,
   int speculations_len,
   int jvmci_data_size
 #endif
   )
   : CompiledMethod(method, "nmethod", type, nmethod_size, sizeof(nmethod), code_buffer, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps, false, true),
-  _is_unloading_state(0),
   _native_receiver_sp_offset(in_ByteSize(-1)),
-  _native_basic_lock_sp_offset(in_ByteSize(-1))
+  _native_basic_lock_sp_offset(in_ByteSize(-1)),
+  _is_unloading_state(0)
 {
   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");
   {

src/hotspot/share/code/nmethod.hpp

@@ -71,11 +71,16 @@ class nmethod : public CompiledMethod {
   friend class JVMCINMethodData;
 
  private:
-  // Shared fields for all nmethod's
-  int       _entry_bci;        // != InvocationEntryBci if this nmethod is an on-stack replacement method
 
   uint64_t  _gc_epoch;
 
+  // not_entrant method removal. Each mark_sweep pass will update
+  // this mark to current sweep invocation count if it is seen on the
+  // stack.  An not_entrant method can be removed when there are no
+  // more activations, i.e., when the _stack_traversal_mark is less than
+  // current sweep traversal index.
+  volatile int64_t _stack_traversal_mark;
+
   // To support simple linked-list chaining of nmethods:
   nmethod*  _osr_link;         // from InstanceKlass::osr_nmethods_head
 
@@ -198,6 +203,9 @@ class nmethod : public CompiledMethod {
   address _verified_entry_point;             // entry point without class check
   address _osr_entry_point;                  // entry point for on stack replacement
 
+  // Shared fields for all nmethod's
+  int _entry_bci;      // != InvocationEntryBci if this nmethod is an on-stack replacement method
+
   // Offsets for different nmethod parts
   int  _exception_offset;
   // Offset of the unwind handler if it exists
@@ -225,21 +233,6 @@ class nmethod : public CompiledMethod {
   int _orig_pc_offset;
 
   int _compile_id;                           // which compilation made this nmethod
-  int _comp_level;                           // compilation level
-
-  // protected by CodeCache_lock
-  bool _has_flushed_dependencies;            // Used for maintenance of dependencies (CodeCache_lock)
-
-  // used by jvmti to track if an event has been posted for this nmethod.
-  bool _unload_reported;
-  bool _load_reported;
-
-  // Protected by CompiledMethod_lock
-  volatile signed char _state;               // {not_installed, in_use, not_entrant, zombie, unloaded}
-
-#ifdef ASSERT
-  bool _oops_are_stale;  // indicates that it's no longer safe to access oops section
-#endif
 
 #if INCLUDE_RTM_OPT
   // RTM state at compile time. Used during deoptimization to decide
@@ -253,23 +246,13 @@ class nmethod : public CompiledMethod {
   // event processing needs to be done.
   volatile jint _lock_count;
 
-  // not_entrant method removal. Each mark_sweep pass will update
-  // this mark to current sweep invocation count if it is seen on the
-  // stack.  An not_entrant method can be removed when there are no
-  // more activations, i.e., when the _stack_traversal_mark is less than
-  // current sweep traversal index.
-  volatile int64_t _stack_traversal_mark;
-
   // The _hotness_counter indicates the hotness of a method. The higher
   // the value the hotter the method. The hotness counter of a nmethod is
   // set to [(ReservedCodeCacheSize / (1024 * 1024)) * 2] each time the method
   // is active while stack scanning (do_stack_scanning()). The hotness
   // counter is decreased (by 1) while sweeping.
   int _hotness_counter;
 
-  // Local state used to keep track of whether unloading is happening or not
-  volatile uint8_t _is_unloading_state;
-
   // These are used for compiled synchronized native methods to
   // locate the owner and stack slot for the BasicLock. They are
   // needed because there is no debug information for compiled native
@@ -281,6 +264,25 @@ class nmethod : public CompiledMethod {
   ByteSize _native_receiver_sp_offset;
   ByteSize _native_basic_lock_sp_offset;
 
+  CompLevel _comp_level;               // compilation level
+
+  // Local state used to keep track of whether unloading is happening or not
+  volatile uint8_t _is_unloading_state;
+
+  // protected by CodeCache_lock
+  bool _has_flushed_dependencies;      // Used for maintenance of dependencies (CodeCache_lock)
+
+  // used by jvmti to track if an event has been posted for this nmethod.
+  bool _unload_reported;
+  bool _load_reported;
+
+  // Protected by CompiledMethod_lock
+  volatile signed char _state;         // {not_installed, in_use, not_entrant, zombie, unloaded}
+
+#ifdef ASSERT
+  bool _oops_are_stale;  // indicates that it's no longer safe to access oops section
+#endif
+
   friend class nmethodLocker;
 
   // For native wrappers
@@ -311,7 +313,7 @@ class nmethod : public CompiledMethod {
           ExceptionHandlerTable* handler_table,
           ImplicitExceptionTable* nul_chk_table,
           AbstractCompiler* compiler,
-          int comp_level
+          CompLevel comp_level
 #if INCLUDE_JVMCI
           , char* speculations,
           int speculations_len,
@@ -359,7 +361,7 @@ class nmethod : public CompiledMethod {
                               ExceptionHandlerTable* handler_table,
                               ImplicitExceptionTable* nul_chk_table,
                               AbstractCompiler* compiler,
-                              int comp_level
+                              CompLevel comp_level
 #if INCLUDE_JVMCI
                               , char* speculations = NULL,
                               int speculations_len = 0,
@@ -372,9 +374,9 @@ class nmethod : public CompiledMethod {
   // Only used for unit tests.
   nmethod()
     : CompiledMethod(),
-      _is_unloading_state(0),
       _native_receiver_sp_offset(in_ByteSize(-1)),
-      _native_basic_lock_sp_offset(in_ByteSize(-1)) {}
+      _native_basic_lock_sp_offset(in_ByteSize(-1)),
+      _is_unloading_state(0) {}
 
 
   static nmethod* new_native_nmethod(const methodHandle& method,

src/hotspot/share/compiler/compilerDefinitions.hpp

@@ -31,7 +31,7 @@
 #include "runtime/globals.hpp"
 
 // The (closed set) of concrete compiler classes.
-enum CompilerType {
+enum CompilerType : u1 {
   compiler_none,
   compiler_c1,
   compiler_c2,
@@ -54,7 +54,7 @@ enum MethodCompilation {
 };
 
 // Enumeration to distinguish tiers of compilation
-enum CompLevel {
+enum CompLevel : s1 {
   CompLevel_any               = -1,        // Used for querying the state
   CompLevel_all               = -1,        // Used for changing the state
   CompLevel_none              = 0,         // Interpreter

src/hotspot/share/jvmci/jvmciRuntime.cpp

@@ -2063,7 +2063,7 @@ JVMCI::CodeInstallResult JVMCIRuntime::register_method(JVMCIEnv* JVMCIENV,
                                 int speculations_len) {
   JVMCI_EXCEPTION_CONTEXT;
   nmethod* nm = NULL;
-  int comp_level = CompLevel_full_optimization;
+  CompLevel comp_level = CompLevel_full_optimization;
   char* failure_detail = NULL;
 
   bool install_default = JVMCIENV->get_HotSpotNmethod_isDefault(nmethod_mirror) != 0;

src/hotspot/share/jvmci/vmStructs_jvmci.cpp

@@ -255,7 +255,7 @@
   nonstatic_field(MethodData,                  _jvmci_ir_size,                                int)                                   \
                                                                                                                                      \
   nonstatic_field(nmethod,                     _verified_entry_point,                         address)                               \
-  nonstatic_field(nmethod,                     _comp_level,                                   int)                                   \
+  nonstatic_field(nmethod,                     _comp_level,                                   CompLevel)                             \
                                                                                                                                      \
   nonstatic_field(ObjArrayKlass,               _element_klass,                                Klass*)                                \
                                                                                                                                      \
@@ -366,6 +366,7 @@
   declare_unsigned_integer_type(size_t)                                   \
   declare_integer_type(intx)                                              \
   declare_unsigned_integer_type(uintx)                                    \
+  declare_integer_type(CompLevel)                                         \
                                                                           \
   declare_toplevel_type(BasicLock)                                        \
   declare_toplevel_type(CompilerToVM)                                     \

src/hotspot/share/runtime/vmStructs.cpp

@@ -665,7 +665,7 @@
   volatile_nonstatic_field(nmethod,            _lock_count,                                   jint)                                  \
   volatile_nonstatic_field(nmethod,            _stack_traversal_mark,                         int64_t)                               \
   nonstatic_field(nmethod,                     _compile_id,                                   int)                                   \
-  nonstatic_field(nmethod,                     _comp_level,                                   int)                                   \
+  nonstatic_field(nmethod,                     _comp_level,                                   CompLevel)                             \
                                                                                                                                      \
   unchecked_c2_static_field(Deoptimization,    _trap_reason_name,                             void*)                                 \
                                                                                                                                      \
@@ -1971,6 +1971,8 @@
   declare_integer_type(AccessFlags)  /* FIXME: wrong type (not integer) */\
   declare_toplevel_type(address)      /* FIXME: should this be an integer type? */\
   declare_integer_type(BasicType)   /* FIXME: wrong type (not integer) */ \
+                                                                          \
+  declare_integer_type(CompLevel)                                         \
   JVMTI_ONLY(declare_toplevel_type(BreakpointInfo))                       \
   JVMTI_ONLY(declare_toplevel_type(BreakpointInfo*))                      \
   declare_toplevel_type(CodeBlob*)                                        \

src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotResolvedJavaMethodImpl.java

@@ -459,7 +459,7 @@ public boolean hasCompiledCode() {
     public boolean hasCompiledCodeAtLevel(int level) {
         long compiledCode = getCompiledCode();
         if (compiledCode != 0) {
-            return UNSAFE.getInt(compiledCode + config().nmethodCompLevelOffset) == level;
+            return UNSAFE.getByte(compiledCode + config().nmethodCompLevelOffset) == level;
         }
         return false;
     }