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comparison src/share/vm/memory/dump.cpp @ 408:52e32c8b317e

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6761092: jvm crashes when CDS is enabled. Summary: CDS hardcoded max c++ virtual method table increased Reviewed-by: coleenp, xlu, jmasa
author acorn
date Wed, 22 Oct 2008 14:48:08 -0400
parents 70c4fb9cf899
children e5b0439ef4ae
comparison
equal deleted inserted replaced
398:443791f333a2 408:52e32c8b317e
816 // Klass objects contain references to c++ vtables in the JVM library. 816 // Klass objects contain references to c++ vtables in the JVM library.
817 // Fix them to point to our constructed vtables. However, don't iterate 817 // Fix them to point to our constructed vtables. However, don't iterate
818 // across the space while doing this, as that causes the vtables to be 818 // across the space while doing this, as that causes the vtables to be
819 // patched, undoing our useful work. Instead, iterate to make a list, 819 // patched, undoing our useful work. Instead, iterate to make a list,
820 // then use the list to do the fixing. 820 // then use the list to do the fixing.
821 //
822 // Our constructed vtables:
823 // Dump time:
824 // 1. init_self_patching_vtbl_list: table of pointers to current virtual method addrs
825 // 2. generate_vtable_methods: create jump table, appended to above vtbl_list
826 // 3. PatchKlassVtables: for Klass list, patch the vtable entry to point to jump table
827 // rather than to current vtbl
828 // Table layout: NOTE FIXED SIZE
829 // 1. vtbl pointers
830 // 2. #Klass X #virtual methods per Klass
831 // 1 entry for each, in the order:
832 // Klass1:method1 entry, Klass1:method2 entry, ... Klass1:method<num_virtuals> entry
833 // Klass2:method1 entry, Klass2:method2 entry, ... Klass2:method<num_virtuals> entry
834 // ...
835 // Klass<vtbl_list_size>:method1 entry, Klass<vtbl_list_size>:method2 entry,
836 // ... Klass<vtbl_list_size>:method<num_virtuals> entry
837 // Sample entry: (Sparc):
838 // save(sp, -256, sp)
839 // ba,pt common_code
840 // mov XXX, %L0 %L0 gets: Klass index <<8 + method index (note: max method index 255)
841 //
842 // Restore time:
843 // 1. initialize_oops: reserve space for table
844 // 2. init_self_patching_vtbl_list: update pointers to NEW virtual method addrs in text
845 //
846 // Execution time:
847 // First virtual method call for any object of these Klass types:
848 // 1. object->klass->klass_part
849 // 2. vtable entry for that klass_part points to the jump table entries
850 // 3. branches to common_code with %O0/klass_part, %L0: Klass index <<8 + method index
851 // 4. common_code:
852 // Get address of new vtbl pointer for this Klass from updated table
853 // Update new vtbl pointer in the Klass: future virtual calls go direct
854 // Jump to method, using new vtbl pointer and method index
821 855
822 class PatchKlassVtables: public ObjectClosure { 856 class PatchKlassVtables: public ObjectClosure {
823 private: 857 private:
824 void* _vtbl_ptr; 858 void* _vtbl_ptr;
825 VirtualSpace* _md_vs; 859 VirtualSpace* _md_vs;