OpenJdk 源码中常见结构体

------------------------------ Asm interpreter ---------------------------------------- Layout of asm interpreter frame: [expression stack ] * <- sp [monitors ] \ ... | monitor block size [monitors ] / [monitor block size ] [byte code pointer ] = bcp() bcp_offset [pointer to locals ] = locals() locals_offset [constant pool cache ] = cache() cache_offset [methodData ] = mdp() mdx_offset [klass of method ] = mirror() mirror_offset [Method* ] = method() method_offset [last sp ] = last_sp() last_sp_offset [old stack pointer ] (sender_sp) sender_sp_offset [old frame pointer ] <- fp = link() [return pc ] [oop temp ] (only for native calls) [locals and parameters ] <- sender sp ------------------------------ Asm interpreter ----------------------------------------

class frame { private: union { intptr_t* _sp; // stack pointer (from Thread::last_Java_sp) int _offset_sp; // used by frames in stack chunks }; address _pc; // program counter (the next instruction after the call) mutable CodeBlob* _cb; mutable const ImmutableOopMap* _oop_map; enum deopt_state { not_deoptimized, is_deoptimized, unknown }; deopt_state _deopt_state; bool _on_heap; enum { sender_sp_offset = 2, metadata_words = sender_sp_offset, } union { intptr_t* _fp; // frame pointer int _offset_fp; // relative frame pointer for use in stack-chunk frames }; union { intptr_t* _unextended_sp; int _offset_unextended_sp; // for use in stack-chunk frames }; }