%verify "executed" %verify "null object" %verify "class cast exception thrown, with correct class name" %verify "class cast exception not thrown on same class" %verify "class cast exception not thrown on subclass" %verify "class not resolved" %verify "class already resolved" /* * Check to see if a cast from one class to another is allowed. */ /* check-cast vAA, class@BBBB */ mov r3, rINST, lsr #8 @ r3<- AA FETCH(r2, 1) @ r2<- BBBB GET_VREG(r9, r3) @ r9<- object ldr r0, [rSELF, #offThread_methodClassDex] @ r0<- pDvmDex cmp r9, #0 @ is object null? ldr r0, [r0, #offDvmDex_pResClasses] @ r0<- pDvmDex->pResClasses beq .L${opcode}_okay @ null obj, cast always succeeds ldr r1, [r0, r2, lsl #2] @ r1<- resolved class ldr r0, [r9, #offObject_clazz] @ r0<- obj->clazz cmp r1, #0 @ have we resolved this before? beq .L${opcode}_resolve @ not resolved, do it now .L${opcode}_resolved: cmp r0, r1 @ same class (trivial success)? bne .L${opcode}_fullcheck @ no, do full check .L${opcode}_okay: FETCH_ADVANCE_INST(2) @ advance rPC, load rINST GET_INST_OPCODE(ip) @ extract opcode from rINST GOTO_OPCODE(ip) @ jump to next instruction %break /* * Trivial test failed, need to perform full check. This is common. * r0 holds obj->clazz * r1 holds desired class resolved from BBBB * r9 holds object */ .L${opcode}_fullcheck: mov r10, r1 @ avoid ClassObject getting clobbered bl dvmInstanceofNonTrivial @ r0<- boolean result cmp r0, #0 @ failed? bne .L${opcode}_okay @ no, success @ A cast has failed. We need to throw a ClassCastException. EXPORT_PC() @ about to throw ldr r0, [r9, #offObject_clazz] @ r0<- obj->clazz (actual class) mov r1, r10 @ r1<- desired class bl dvmThrowClassCastException b common_exceptionThrown /* * Resolution required. This is the least-likely path. * * r2 holds BBBB * r9 holds object */ .L${opcode}_resolve: EXPORT_PC() @ resolve() could throw ldr r3, [rSELF, #offThread_method] @ r3<- self->method mov r1, r2 @ r1<- BBBB mov r2, #0 @ r2<- false ldr r0, [r3, #offMethod_clazz] @ r0<- method->clazz bl dvmResolveClass @ r0<- resolved ClassObject ptr cmp r0, #0 @ got null? beq common_exceptionThrown @ yes, handle exception mov r1, r0 @ r1<- class resolved from BBB ldr r0, [r9, #offObject_clazz] @ r0<- obj->clazz b .L${opcode}_resolved @ pick up where we left off