1// Copyright 2011 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//
6//     * Redistributions of source code must retain the above copyright
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
10//       disclaimer in the documentation and/or other materials provided
11//       with the distribution.
12//     * Neither the name of Google Inc. nor the names of its
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
18// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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_X64)
31
32#include "assembler.h"
33#include "codegen.h"
34#include "debug.h"
35
36
37namespace v8 {
38namespace internal {
39
40#ifdef ENABLE_DEBUGGER_SUPPORT
41
42bool BreakLocationIterator::IsDebugBreakAtReturn()  {
43  return Debug::IsDebugBreakAtReturn(rinfo());
44}
45
46
47// Patch the JS frame exit code with a debug break call. See
48// CodeGenerator::VisitReturnStatement and VirtualFrame::Exit in codegen-x64.cc
49// for the precise return instructions sequence.
50void BreakLocationIterator::SetDebugBreakAtReturn()  {
51  ASSERT(Assembler::kJSReturnSequenceLength >=
52         Assembler::kCallInstructionLength);
53  rinfo()->PatchCodeWithCall(
54      Isolate::Current()->debug()->debug_break_return()->entry(),
55      Assembler::kJSReturnSequenceLength - Assembler::kCallInstructionLength);
56}
57
58
59// Restore the JS frame exit code.
60void BreakLocationIterator::ClearDebugBreakAtReturn() {
61  rinfo()->PatchCode(original_rinfo()->pc(),
62                     Assembler::kJSReturnSequenceLength);
63}
64
65
66// A debug break in the frame exit code is identified by the JS frame exit code
67// having been patched with a call instruction.
68bool Debug::IsDebugBreakAtReturn(v8::internal::RelocInfo* rinfo) {
69  ASSERT(RelocInfo::IsJSReturn(rinfo->rmode()));
70  return rinfo->IsPatchedReturnSequence();
71}
72
73
74bool BreakLocationIterator::IsDebugBreakAtSlot() {
75  ASSERT(IsDebugBreakSlot());
76  // Check whether the debug break slot instructions have been patched.
77  return !Assembler::IsNop(rinfo()->pc());
78}
79
80
81void BreakLocationIterator::SetDebugBreakAtSlot() {
82  ASSERT(IsDebugBreakSlot());
83  rinfo()->PatchCodeWithCall(
84      Isolate::Current()->debug()->debug_break_slot()->entry(),
85      Assembler::kDebugBreakSlotLength - Assembler::kCallInstructionLength);
86}
87
88
89void BreakLocationIterator::ClearDebugBreakAtSlot() {
90  ASSERT(IsDebugBreakSlot());
91  rinfo()->PatchCode(original_rinfo()->pc(), Assembler::kDebugBreakSlotLength);
92}
93
94
95#define __ ACCESS_MASM(masm)
96
97
98static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
99                                          RegList object_regs,
100                                          RegList non_object_regs,
101                                          bool convert_call_to_jmp) {
102  // Enter an internal frame.
103  {
104    FrameScope scope(masm, StackFrame::INTERNAL);
105
106    // Store the registers containing live values on the expression stack to
107    // make sure that these are correctly updated during GC. Non object values
108    // are stored as as two smis causing it to be untouched by GC.
109    ASSERT((object_regs & ~kJSCallerSaved) == 0);
110    ASSERT((non_object_regs & ~kJSCallerSaved) == 0);
111    ASSERT((object_regs & non_object_regs) == 0);
112    for (int i = 0; i < kNumJSCallerSaved; i++) {
113      int r = JSCallerSavedCode(i);
114      Register reg = { r };
115      ASSERT(!reg.is(kScratchRegister));
116      if ((object_regs & (1 << r)) != 0) {
117        __ push(reg);
118      }
119      // Store the 64-bit value as two smis.
120      if ((non_object_regs & (1 << r)) != 0) {
121        __ movq(kScratchRegister, reg);
122        __ Integer32ToSmi(reg, reg);
123        __ push(reg);
124        __ sar(kScratchRegister, Immediate(32));
125        __ Integer32ToSmi(kScratchRegister, kScratchRegister);
126        __ push(kScratchRegister);
127      }
128    }
129
130#ifdef DEBUG
131    __ RecordComment("// Calling from debug break to runtime - come in - over");
132#endif
133    __ Set(rax, 0);  // No arguments (argc == 0).
134    __ movq(rbx, ExternalReference::debug_break(masm->isolate()));
135
136    CEntryStub ceb(1);
137    __ CallStub(&ceb);
138
139    // Restore the register values from the expression stack.
140    for (int i = kNumJSCallerSaved - 1; i >= 0; i--) {
141      int r = JSCallerSavedCode(i);
142      Register reg = { r };
143      if (FLAG_debug_code) {
144        __ Set(reg, kDebugZapValue);
145      }
146      if ((object_regs & (1 << r)) != 0) {
147        __ pop(reg);
148      }
149      // Reconstruct the 64-bit value from two smis.
150      if ((non_object_regs & (1 << r)) != 0) {
151        __ pop(kScratchRegister);
152        __ SmiToInteger32(kScratchRegister, kScratchRegister);
153        __ shl(kScratchRegister, Immediate(32));
154        __ pop(reg);
155        __ SmiToInteger32(reg, reg);
156        __ or_(reg, kScratchRegister);
157      }
158    }
159
160    // Get rid of the internal frame.
161  }
162
163  // If this call did not replace a call but patched other code then there will
164  // be an unwanted return address left on the stack. Here we get rid of that.
165  if (convert_call_to_jmp) {
166    __ addq(rsp, Immediate(kPointerSize));
167  }
168
169  // Now that the break point has been handled, resume normal execution by
170  // jumping to the target address intended by the caller and that was
171  // overwritten by the address of DebugBreakXXX.
172  ExternalReference after_break_target =
173      ExternalReference(Debug_Address::AfterBreakTarget(), masm->isolate());
174  __ movq(kScratchRegister, after_break_target);
175  __ jmp(Operand(kScratchRegister, 0));
176}
177
178
179void Debug::GenerateLoadICDebugBreak(MacroAssembler* masm) {
180  // Register state for IC load call (from ic-x64.cc).
181  // ----------- S t a t e -------------
182  //  -- rax    : receiver
183  //  -- rcx    : name
184  // -----------------------------------
185  Generate_DebugBreakCallHelper(masm, rax.bit() | rcx.bit(), 0, false);
186}
187
188
189void Debug::GenerateStoreICDebugBreak(MacroAssembler* masm) {
190  // Register state for IC store call (from ic-x64.cc).
191  // ----------- S t a t e -------------
192  //  -- rax    : value
193  //  -- rcx    : name
194  //  -- rdx    : receiver
195  // -----------------------------------
196  Generate_DebugBreakCallHelper(
197      masm, rax.bit() | rcx.bit() | rdx.bit(), 0, false);
198}
199
200
201void Debug::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
202  // Register state for keyed IC load call (from ic-x64.cc).
203  // ----------- S t a t e -------------
204  //  -- rax     : key
205  //  -- rdx     : receiver
206  // -----------------------------------
207  Generate_DebugBreakCallHelper(masm, rax.bit() | rdx.bit(), 0, false);
208}
209
210
211void Debug::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
212  // Register state for keyed IC load call (from ic-x64.cc).
213  // ----------- S t a t e -------------
214  //  -- rax    : value
215  //  -- rcx    : key
216  //  -- rdx    : receiver
217  // -----------------------------------
218  Generate_DebugBreakCallHelper(
219      masm, rax.bit() | rcx.bit() | rdx.bit(), 0, false);
220}
221
222
223void Debug::GenerateCallICDebugBreak(MacroAssembler* masm) {
224  // Register state for IC call call (from ic-x64.cc)
225  // ----------- S t a t e -------------
226  //  -- rcx: function name
227  // -----------------------------------
228  Generate_DebugBreakCallHelper(masm, rcx.bit(), 0, false);
229}
230
231
232void Debug::GenerateReturnDebugBreak(MacroAssembler* masm) {
233  // Register state just before return from JS function (from codegen-x64.cc).
234  // ----------- S t a t e -------------
235  //  -- rax: return value
236  // -----------------------------------
237  Generate_DebugBreakCallHelper(masm, rax.bit(), 0, true);
238}
239
240
241void Debug::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) {
242  // Register state for CallFunctionStub (from code-stubs-x64.cc).
243  // ----------- S t a t e -------------
244  //  -- rdi : function
245  // -----------------------------------
246  Generate_DebugBreakCallHelper(masm, rdi.bit(), 0, false);
247}
248
249
250void Debug::GenerateCallFunctionStubRecordDebugBreak(MacroAssembler* masm) {
251  // Register state for CallFunctionStub (from code-stubs-x64.cc).
252  // ----------- S t a t e -------------
253  //  -- rdi : function
254  //  -- rbx: cache cell for call target
255  // -----------------------------------
256  Generate_DebugBreakCallHelper(masm, rbx.bit() | rdi.bit(), 0, false);
257}
258
259
260void Debug::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) {
261  // Register state for CallConstructStub (from code-stubs-x64.cc).
262  // rax is the actual number of arguments not encoded as a smi, see comment
263  // above IC call.
264  // ----------- S t a t e -------------
265  //  -- rax: number of arguments
266  // -----------------------------------
267  // The number of arguments in rax is not smi encoded.
268  Generate_DebugBreakCallHelper(masm, rdi.bit(), rax.bit(), false);
269}
270
271
272void Debug::GenerateCallConstructStubRecordDebugBreak(MacroAssembler* masm) {
273  // Register state for CallConstructStub (from code-stubs-x64.cc).
274  // rax is the actual number of arguments not encoded as a smi, see comment
275  // above IC call.
276  // ----------- S t a t e -------------
277  //  -- rax: number of arguments
278  //  -- rbx: cache cell for call target
279  // -----------------------------------
280  // The number of arguments in rax is not smi encoded.
281  Generate_DebugBreakCallHelper(masm, rbx.bit() | rdi.bit(), rax.bit(), false);
282}
283
284
285void Debug::GenerateSlot(MacroAssembler* masm) {
286  // Generate enough nop's to make space for a call instruction.
287  Label check_codesize;
288  __ bind(&check_codesize);
289  __ RecordDebugBreakSlot();
290  __ Nop(Assembler::kDebugBreakSlotLength);
291  ASSERT_EQ(Assembler::kDebugBreakSlotLength,
292            masm->SizeOfCodeGeneratedSince(&check_codesize));
293}
294
295
296void Debug::GenerateSlotDebugBreak(MacroAssembler* masm) {
297  // In the places where a debug break slot is inserted no registers can contain
298  // object pointers.
299  Generate_DebugBreakCallHelper(masm, 0, 0, true);
300}
301
302
303void Debug::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
304  masm->ret(0);
305}
306
307
308void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
309  ExternalReference restarter_frame_function_slot =
310      ExternalReference(Debug_Address::RestarterFrameFunctionPointer(),
311                        masm->isolate());
312  __ movq(rax, restarter_frame_function_slot);
313  __ movq(Operand(rax, 0), Immediate(0));
314
315  // We do not know our frame height, but set rsp based on rbp.
316  __ lea(rsp, Operand(rbp, -1 * kPointerSize));
317
318  __ pop(rdi);  // Function.
319  __ pop(rbp);
320
321  // Load context from the function.
322  __ movq(rsi, FieldOperand(rdi, JSFunction::kContextOffset));
323
324  // Get function code.
325  __ movq(rdx, FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset));
326  __ movq(rdx, FieldOperand(rdx, SharedFunctionInfo::kCodeOffset));
327  __ lea(rdx, FieldOperand(rdx, Code::kHeaderSize));
328
329  // Re-run JSFunction, rdi is function, rsi is context.
330  __ jmp(rdx);
331}
332
333const bool Debug::kFrameDropperSupported = true;
334
335#undef __
336
337#endif  // ENABLE_DEBUGGER_SUPPORT
338
339} }  // namespace v8::internal
340
341#endif  // V8_TARGET_ARCH_X64
342