1 /*
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4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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10  * This code is distributed in the hope that it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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13  * version 2 for more details (a copy is included in the LICENSE file that
14  * accompanied this code).
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25 
26 #include "precompiled.hpp"
27 #ifdef COMPILER2
28 #include "asm/macroAssembler.inline.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "code/vmreg.hpp"
31 #include "interpreter/interpreter.hpp"
32 #include "interpreter/interp_masm.hpp"
33 #include "memory/resourceArea.hpp"
34 #include "nativeInst_ppc.hpp"
35 #include "opto/runtime.hpp"
36 #include "runtime/interfaceSupport.inline.hpp"
37 #include "runtime/sharedRuntime.hpp"
38 #include "runtime/stubRoutines.hpp"
39 #include "runtime/vframeArray.hpp"
40 #include "utilities/globalDefinitions.hpp"
41 #endif
42 
43 #define __ masm->
44 
45 
46 #ifdef COMPILER2
47 
48 //------------------------------generate_exception_blob---------------------------
49 // Creates exception blob at the end.
50 // Using exception blob, this code is jumped from a compiled method.
51 //
52 // Given an exception pc at a call we call into the runtime for the
53 // handler in this method. This handler might merely restore state
54 // (i.e. callee save registers) unwind the frame and jump to the
55 // exception handler for the nmethod if there is no Java level handler
56 // for the nmethod.
57 //
58 // This code is entered with a jmp.
59 //
60 // Arguments:
61 //   R3_ARG1: exception oop
62 //   R4_ARG2: exception pc
63 //
64 // Results:
65 //   R3_ARG1: exception oop
66 //   R4_ARG2: exception pc in caller
67 //   destination: exception handler of caller
68 //
69 // Note: the exception pc MUST be at a call (precise debug information)
70 //
generate_exception_blob()71 void OptoRuntime::generate_exception_blob() {
72   // Allocate space for the code.
73   ResourceMark rm;
74   // Setup code generation tools.
75   CodeBuffer buffer("exception_blob", 2048, 1024);
76   InterpreterMacroAssembler* masm = new InterpreterMacroAssembler(&buffer);
77 
78   address start = __ pc();
79 
80   int frame_size_in_bytes = frame::abi_reg_args_size;
81   OopMap* map = new OopMap(frame_size_in_bytes / sizeof(jint), 0);
82 
83   // Exception pc is 'return address' for stack walker.
84   __ std(R4_ARG2/*exception pc*/, _abi(lr), R1_SP);
85 
86   // Store the exception in the Thread object.
87   __ std(R3_ARG1/*exception oop*/, in_bytes(JavaThread::exception_oop_offset()), R16_thread);
88   __ std(R4_ARG2/*exception pc*/,  in_bytes(JavaThread::exception_pc_offset()),  R16_thread);
89 
90   // Save callee-saved registers.
91   // Push a C frame for the exception blob. It is needed for the C call later on.
92   __ push_frame_reg_args(0, R11_scratch1);
93 
94   // This call does all the hard work. It checks if an exception handler
95   // exists in the method.
96   // If so, it returns the handler address.
97   // If not, it prepares for stack-unwinding, restoring the callee-save
98   // registers of the frame being removed.
99   __ set_last_Java_frame(/*sp=*/R1_SP, noreg);
100 
101   __ mr(R3_ARG1, R16_thread);
102 #if defined(ABI_ELFv2)
103   __ call_c((address) OptoRuntime::handle_exception_C, relocInfo::none);
104 #else
105   __ call_c(CAST_FROM_FN_PTR(FunctionDescriptor*, OptoRuntime::handle_exception_C),
106             relocInfo::none);
107 #endif
108   address calls_return_pc = __ last_calls_return_pc();
109 # ifdef ASSERT
110   __ cmpdi(CCR0, R3_RET, 0);
111   __ asm_assert_ne("handle_exception_C must not return NULL");
112 # endif
113 
114   // Set an oopmap for the call site. This oopmap will only be used if we
115   // are unwinding the stack. Hence, all locations will be dead.
116   // Callee-saved registers will be the same as the frame above (i.e.,
117   // handle_exception_stub), since they were restored when we got the
118   // exception.
119   OopMapSet* oop_maps = new OopMapSet();
120   oop_maps->add_gc_map(calls_return_pc - start, map);
121 
122   __ mtctr(R3_RET); // Move address of exception handler to SR_CTR.
123   __ reset_last_Java_frame();
124   __ pop_frame();
125 
126   // We have a handler in register SR_CTR (could be deopt blob).
127 
128   // Get the exception oop.
129   __ ld(R3_ARG1, in_bytes(JavaThread::exception_oop_offset()), R16_thread);
130 
131   // Get the exception pc in case we are deoptimized.
132   __ ld(R4_ARG2, in_bytes(JavaThread::exception_pc_offset()), R16_thread);
133 
134   // Reset thread values.
135   __ li(R0, 0);
136 #ifdef ASSERT
137   __ std(R0, in_bytes(JavaThread::exception_handler_pc_offset()), R16_thread);
138   __ std(R0, in_bytes(JavaThread::exception_pc_offset()), R16_thread);
139 #endif
140   // Clear the exception oop so GC no longer processes it as a root.
141   __ std(R0, in_bytes(JavaThread::exception_oop_offset()), R16_thread);
142 
143   // Move exception pc into SR_LR.
144   __ mtlr(R4_ARG2);
145   __ bctr();
146 
147   // Make sure all code is generated.
148   masm->flush();
149 
150   // Set exception blob.
151   _exception_blob = ExceptionBlob::create(&buffer, oop_maps,
152                                           frame_size_in_bytes/wordSize);
153 }
154 
155 #endif // COMPILER2
156