Thu, 07 Apr 2011 09:53:20 -0700
7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error
Summary: A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.
Reviewed-by: kvn, iveresov, never, tonyp, dholmes
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25 #ifndef CPU_SPARC_VM_REGISTERMAP_SPARC_HPP
26 #define CPU_SPARC_VM_REGISTERMAP_SPARC_HPP
28 // machine-dependent implemention for register maps
29 friend class frame;
31 private:
32 intptr_t* _window; // register window save area (for L and I regs)
33 intptr_t* _younger_window; // previous save area (for O regs, if needed)
35 address pd_location(VMReg reg) const;
36 void pd_clear();
37 void pd_initialize_from(const RegisterMap* map) {
38 _window = map->_window;
39 _younger_window = map->_younger_window;
40 _location_valid[0] = 0; // avoid the shift_individual_registers game
41 }
42 void pd_initialize() {
43 _window = NULL;
44 _younger_window = NULL;
45 _location_valid[0] = 0; // avoid the shift_individual_registers game
46 }
47 void shift_window(intptr_t* sp, intptr_t* younger_sp) {
48 _window = sp;
49 _younger_window = younger_sp;
50 // Throw away locations for %i, %o, and %l registers:
51 // But do not throw away %g register locs.
52 if (_location_valid[0] != 0) shift_individual_registers();
53 }
54 void shift_individual_registers();
55 // When popping out of compiled frames, we make all IRegs disappear.
56 void make_integer_regs_unsaved() { _location_valid[0] = 0; }
58 #endif // CPU_SPARC_VM_REGISTERMAP_SPARC_HPP