debug-arm.cc revision 80d68eab642096c1a48b6474d6ec33064b0ad1f5 
1// Copyright 2006-2008 the V8 project authors. All rights reserved.
2// Redistribution and use in source and binary forms, with or without
3// modification, are permitted provided that the following conditions are
4// met:
5//
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7//       notice, this list of conditions and the following disclaimer.
8//     * Redistributions in binary form must reproduce the above
9//       copyright notice, this list of conditions and the following
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11//       with the distribution.
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13//       contributors may be used to endorse or promote products derived
14//       from this software without specific prior written permission.
15//
16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
28#include "v8.h"
29
30#if defined(V8_TARGET_ARCH_ARM)
31
32#include "codegen-inl.h"
33#include "debug.h"
34
35namespace v8 {
36namespace internal {
37
38#ifdef ENABLE_DEBUGGER_SUPPORT
39bool BreakLocationIterator::IsDebugBreakAtReturn() {
40  return Debug::IsDebugBreakAtReturn(rinfo());
41}
42
43
44void BreakLocationIterator::SetDebugBreakAtReturn() {
45  // Patch the code changing the return from JS function sequence from
46  //   mov sp, fp
47  //   ldmia sp!, {fp, lr}
48  //   add sp, sp, #4
49  //   bx lr
50  // to a call to the debug break return code.
51  // #if USE_BLX
52  //   ldr ip, [pc, #0]
53  //   blx ip
54  // #else
55  //   mov lr, pc
56  //   ldr pc, [pc, #-4]
57  // #endif
58  //   <debug break return code entry point address>
59  //   bktp 0
60  CodePatcher patcher(rinfo()->pc(), Assembler::kJSReturnSequenceInstructions);
61#ifdef USE_BLX
62  patcher.masm()->ldr(v8::internal::ip, MemOperand(v8::internal::pc, 0));
63  patcher.masm()->blx(v8::internal::ip);
64#else
65  patcher.masm()->mov(v8::internal::lr, v8::internal::pc);
66  patcher.masm()->ldr(v8::internal::pc, MemOperand(v8::internal::pc, -4));
67#endif
68  patcher.Emit(Debug::debug_break_return()->entry());
69  patcher.masm()->bkpt(0);
70}
71
72
73// Restore the JS frame exit code.
74void BreakLocationIterator::ClearDebugBreakAtReturn() {
75  rinfo()->PatchCode(original_rinfo()->pc(),
76                     Assembler::kJSReturnSequenceInstructions);
77}
78
79
80// A debug break in the frame exit code is identified by the JS frame exit code
81// having been patched with a call instruction.
82bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
83  ASSERT(RelocInfo::IsJSReturn(rinfo->rmode()));
84  return rinfo->IsPatchedReturnSequence();
85}
86
87
88bool BreakLocationIterator::IsDebugBreakAtSlot() {
89  ASSERT(IsDebugBreakSlot());
90  // Check whether the debug break slot instructions have been patched.
91  return rinfo()->IsPatchedDebugBreakSlotSequence();
92}
93
94
95void BreakLocationIterator::SetDebugBreakAtSlot() {
96  ASSERT(IsDebugBreakSlot());
97  // Patch the code changing the debug break slot code from
98  //   mov r2, r2
99  //   mov r2, r2
100  //   mov r2, r2
101  // to a call to the debug break slot code.
102  // #if USE_BLX
103  //   ldr ip, [pc, #0]
104  //   blx ip
105  // #else
106  //   mov lr, pc
107  //   ldr pc, [pc, #-4]
108  // #endif
109  //   <debug break slot code entry point address>
110  CodePatcher patcher(rinfo()->pc(), Assembler::kDebugBreakSlotInstructions);
111#ifdef USE_BLX
112  patcher.masm()->ldr(v8::internal::ip, MemOperand(v8::internal::pc, 0));
113  patcher.masm()->blx(v8::internal::ip);
114#else
115  patcher.masm()->mov(v8::internal::lr, v8::internal::pc);
116  patcher.masm()->ldr(v8::internal::pc, MemOperand(v8::internal::pc, -4));
117#endif
118  patcher.Emit(Debug::debug_break_return()->entry());
119}
120
121
122void BreakLocationIterator::ClearDebugBreakAtSlot() {
123  ASSERT(IsDebugBreakSlot());
124  rinfo()->PatchCode(original_rinfo()->pc(),
125                     Assembler::kDebugBreakSlotInstructions);
126}
127
128
129#define __ ACCESS_MASM(masm)
130
131
132static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
133                                          RegList object_regs,
134                                          RegList non_object_regs) {
135  __ EnterInternalFrame();
136
137  // Store the registers containing live values on the expression stack to
138  // make sure that these are correctly updated during GC. Non object values
139  // are stored as a smi causing it to be untouched by GC.
140  ASSERT((object_regs & ~kJSCallerSaved) == 0);
141  ASSERT((non_object_regs & ~kJSCallerSaved) == 0);
142  ASSERT((object_regs & non_object_regs) == 0);
143  if ((object_regs | non_object_regs) != 0) {
144    for (int i = 0; i < kNumJSCallerSaved; i++) {
145      int r = JSCallerSavedCode(i);
146      Register reg = { r };
147      if ((non_object_regs & (1 << r)) != 0) {
148        if (FLAG_debug_code) {
149          __ tst(reg, Operand(0xc0000000));
150          __ Assert(eq, "Unable to encode value as smi");
151        }
152        __ mov(reg, Operand(reg, LSL, kSmiTagSize));
153      }
154    }
155    __ stm(db_w, sp, object_regs | non_object_regs);
156  }
157
158#ifdef DEBUG
159  __ RecordComment("// Calling from debug break to runtime - come in - over");
160#endif
161  __ mov(r0, Operand(0));  // no arguments
162  __ mov(r1, Operand(ExternalReference::debug_break()));
163
164  CEntryStub ceb(1);
165  __ CallStub(&ceb);
166
167  // Restore the register values from the expression stack.
168  if ((object_regs | non_object_regs) != 0) {
169    __ ldm(ia_w, sp, object_regs | non_object_regs);
170    for (int i = 0; i < kNumJSCallerSaved; i++) {
171      int r = JSCallerSavedCode(i);
172      Register reg = { r };
173      if ((non_object_regs & (1 << r)) != 0) {
174        __ mov(reg, Operand(reg, LSR, kSmiTagSize));
175      }
176      if (FLAG_debug_code &&
177          (((object_regs |non_object_regs) & (1 << r)) == 0)) {
178        __ mov(reg, Operand(kDebugZapValue));
179      }
180    }
181  }
182
183  __ LeaveInternalFrame();
184
185  // Now that the break point has been handled, resume normal execution by
186  // jumping to the target address intended by the caller and that was
187  // overwritten by the address of DebugBreakXXX.
188  __ mov(ip, Operand(ExternalReference(Debug_Address::AfterBreakTarget())));
189  __ ldr(ip, MemOperand(ip));
190  __ Jump(ip);
191}
192
193
194void Debug::GenerateLoadICDebugBreak(MacroAssembler* masm) {
195  // Calling convention for IC load (from ic-arm.cc).
196  // ----------- S t a t e -------------
197  //  -- r2    : name
198  //  -- lr    : return address
199  //  -- r0    : receiver
200  //  -- [sp]  : receiver
201  // -----------------------------------
202  // Registers r0 and r2 contain objects that need to be pushed on the
203  // expression stack of the fake JS frame.
204  Generate_DebugBreakCallHelper(masm, r0.bit() | r2.bit(), 0);
205}
206
207
208void Debug::GenerateStoreICDebugBreak(MacroAssembler* masm) {
209  // Calling convention for IC store (from ic-arm.cc).
210  // ----------- S t a t e -------------
211  //  -- r0    : value
212  //  -- r1    : receiver
213  //  -- r2    : name
214  //  -- lr    : return address
215  // -----------------------------------
216  // Registers r0, r1, and r2 contain objects that need to be pushed on the
217  // expression stack of the fake JS frame.
218  Generate_DebugBreakCallHelper(masm, r0.bit() | r1.bit() | r2.bit(), 0);
219}
220
221
222void Debug::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
223  // ---------- S t a t e --------------
224  //  -- lr     : return address
225  //  -- r0     : key
226  //  -- r1     : receiver
227  Generate_DebugBreakCallHelper(masm, r0.bit() | r1.bit(), 0);
228}
229
230
231void Debug::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
232  // ---------- S t a t e --------------
233  //  -- r0     : value
234  //  -- r1     : key
235  //  -- r2     : receiver
236  //  -- lr     : return address
237  Generate_DebugBreakCallHelper(masm, r0.bit() | r1.bit() | r2.bit(), 0);
238}
239
240
241void Debug::GenerateCallICDebugBreak(MacroAssembler* masm) {
242  // Calling convention for IC call (from ic-arm.cc)
243  // ----------- S t a t e -------------
244  //  -- r2     : name
245  // -----------------------------------
246  Generate_DebugBreakCallHelper(masm, r2.bit(), 0);
247}
248
249
250void Debug::GenerateConstructCallDebugBreak(MacroAssembler* masm) {
251  // Calling convention for construct call (from builtins-arm.cc)
252  //  -- r0     : number of arguments (not smi)
253  //  -- r1     : constructor function
254  Generate_DebugBreakCallHelper(masm, r1.bit(), r0.bit());
255}
256
257
258void Debug::GenerateReturnDebugBreak(MacroAssembler* masm) {
259  // In places other than IC call sites it is expected that r0 is TOS which
260  // is an object - this is not generally the case so this should be used with
261  // care.
262  Generate_DebugBreakCallHelper(masm, r0.bit(), 0);
263}
264
265
266void Debug::GenerateStubNoRegistersDebugBreak(MacroAssembler* masm) {
267  // ----------- S t a t e -------------
268  //  No registers used on entry.
269  // -----------------------------------
270  Generate_DebugBreakCallHelper(masm, 0, 0);
271}
272
273
274void Debug::GenerateSlot(MacroAssembler* masm) {
275  // Generate enough nop's to make space for a call instruction. Avoid emitting
276  // the constant pool in the debug break slot code.
277  Assembler::BlockConstPoolScope block_const_pool(masm);
278  Label check_codesize;
279  __ bind(&check_codesize);
280  __ RecordDebugBreakSlot();
281  for (int i = 0; i < Assembler::kDebugBreakSlotInstructions; i++) {
282    __ nop(2);
283  }
284  ASSERT_EQ(Assembler::kDebugBreakSlotInstructions,
285            masm->InstructionsGeneratedSince(&check_codesize));
286}
287
288
289void Debug::GenerateSlotDebugBreak(MacroAssembler* masm) {
290  // In the places where a debug break slot is inserted no registers can contain
291  // object pointers.
292  Generate_DebugBreakCallHelper(masm, 0, 0);
293}
294
295
296void Debug::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
297  masm->Abort("LiveEdit frame dropping is not supported on arm");
298}
299
300
301void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
302  masm->Abort("LiveEdit frame dropping is not supported on arm");
303}
304
305const bool Debug::kFrameDropperSupported = false;
306
307#undef __
308
309
310
311#endif  // ENABLE_DEBUGGER_SUPPORT
312
313} }  // namespace v8::internal
314
315#endif  // V8_TARGET_ARCH_ARM
316