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_IA32)
31
32#include "codegen.h"
33#include "debug.h"
34
35
36namespace v8 {
37namespace internal {
38
39#ifdef ENABLE_DEBUGGER_SUPPORT
40
41bool BreakLocationIterator::IsDebugBreakAtReturn() {
42  return Debug::IsDebugBreakAtReturn(rinfo());
43}
44
45
46// Patch the JS frame exit code with a debug break call. See
47// CodeGenerator::VisitReturnStatement and VirtualFrame::Exit in codegen-ia32.cc
48// for the precise return instructions sequence.
49void BreakLocationIterator::SetDebugBreakAtReturn() {
50  ASSERT(Assembler::kJSReturnSequenceLength >=
51         Assembler::kCallInstructionLength);
52  Isolate* isolate = Isolate::Current();
53  rinfo()->PatchCodeWithCall(isolate->debug()->debug_break_return()->entry(),
54      Assembler::kJSReturnSequenceLength - Assembler::kCallInstructionLength);
55}
56
57
58// Restore the JS frame exit code.
59void BreakLocationIterator::ClearDebugBreakAtReturn() {
60  rinfo()->PatchCode(original_rinfo()->pc(),
61                     Assembler::kJSReturnSequenceLength);
62}
63
64
65// A debug break in the frame exit code is identified by the JS frame exit code
66// having been patched with a call instruction.
67bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
68  ASSERT(RelocInfo::IsJSReturn(rinfo->rmode()));
69  return rinfo->IsPatchedReturnSequence();
70}
71
72
73bool BreakLocationIterator::IsDebugBreakAtSlot() {
74  ASSERT(IsDebugBreakSlot());
75  // Check whether the debug break slot instructions have been patched.
76  return rinfo()->IsPatchedDebugBreakSlotSequence();
77}
78
79
80void BreakLocationIterator::SetDebugBreakAtSlot() {
81  ASSERT(IsDebugBreakSlot());
82  Isolate* isolate = Isolate::Current();
83  rinfo()->PatchCodeWithCall(
84      isolate->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 a smi 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      if ((object_regs & (1 << r)) != 0) {
116        __ push(reg);
117      }
118      if ((non_object_regs & (1 << r)) != 0) {
119        if (FLAG_debug_code) {
120          __ test(reg, Immediate(0xc0000000));
121          __ Assert(zero, "Unable to encode value as smi");
122        }
123        __ SmiTag(reg);
124        __ push(reg);
125      }
126    }
127
128#ifdef DEBUG
129    __ RecordComment("// Calling from debug break to runtime - come in - over");
130#endif
131    __ Set(eax, Immediate(0));  // No arguments.
132    __ mov(ebx, Immediate(ExternalReference::debug_break(masm->isolate())));
133
134    CEntryStub ceb(1);
135    __ CallStub(&ceb);
136
137    // Restore the register values containing object pointers from the
138    // expression stack.
139    for (int i = kNumJSCallerSaved; --i >= 0;) {
140      int r = JSCallerSavedCode(i);
141      Register reg = { r };
142      if (FLAG_debug_code) {
143        __ Set(reg, Immediate(kDebugZapValue));
144      }
145      if ((object_regs & (1 << r)) != 0) {
146        __ pop(reg);
147      }
148      if ((non_object_regs & (1 << r)) != 0) {
149        __ pop(reg);
150        __ SmiUntag(reg);
151      }
152    }
153
154    // Get rid of the internal frame.
155  }
156
157  // If this call did not replace a call but patched other code then there will
158  // be an unwanted return address left on the stack. Here we get rid of that.
159  if (convert_call_to_jmp) {
160    __ add(esp, Immediate(kPointerSize));
161  }
162
163  // Now that the break point has been handled, resume normal execution by
164  // jumping to the target address intended by the caller and that was
165  // overwritten by the address of DebugBreakXXX.
166  ExternalReference after_break_target =
167      ExternalReference(Debug_Address::AfterBreakTarget(), masm->isolate());
168  __ jmp(Operand::StaticVariable(after_break_target));
169}
170
171
172void Debug::GenerateLoadICDebugBreak(MacroAssembler* masm) {
173  // Register state for IC load call (from ic-ia32.cc).
174  // ----------- S t a t e -------------
175  //  -- eax    : receiver
176  //  -- ecx    : name
177  // -----------------------------------
178  Generate_DebugBreakCallHelper(masm, eax.bit() | ecx.bit(), 0, false);
179}
180
181
182void Debug::GenerateStoreICDebugBreak(MacroAssembler* masm) {
183  // Register state for IC store call (from ic-ia32.cc).
184  // ----------- S t a t e -------------
185  //  -- eax    : value
186  //  -- ecx    : name
187  //  -- edx    : receiver
188  // -----------------------------------
189  Generate_DebugBreakCallHelper(
190      masm, eax.bit() | ecx.bit() | edx.bit(), 0, false);
191}
192
193
194void Debug::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
195  // Register state for keyed IC load call (from ic-ia32.cc).
196  // ----------- S t a t e -------------
197  //  -- edx    : receiver
198  //  -- eax    : key
199  // -----------------------------------
200  Generate_DebugBreakCallHelper(masm, eax.bit() | edx.bit(), 0, false);
201}
202
203
204void Debug::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
205  // Register state for keyed IC load call (from ic-ia32.cc).
206  // ----------- S t a t e -------------
207  //  -- eax    : value
208  //  -- ecx    : key
209  //  -- edx    : receiver
210  // -----------------------------------
211  Generate_DebugBreakCallHelper(
212      masm, eax.bit() | ecx.bit() | edx.bit(), 0, false);
213}
214
215
216void Debug::GenerateCallICDebugBreak(MacroAssembler* masm) {
217  // Register state for keyed IC call call (from ic-ia32.cc)
218  // ----------- S t a t e -------------
219  //  -- ecx: name
220  // -----------------------------------
221  Generate_DebugBreakCallHelper(masm, ecx.bit(), 0, false);
222}
223
224
225void Debug::GenerateReturnDebugBreak(MacroAssembler* masm) {
226  // Register state just before return from JS function (from codegen-ia32.cc).
227  // ----------- S t a t e -------------
228  //  -- eax: return value
229  // -----------------------------------
230  Generate_DebugBreakCallHelper(masm, eax.bit(), 0, true);
231}
232
233
234void Debug::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) {
235  // Register state for CallFunctionStub (from code-stubs-ia32.cc).
236  // ----------- S t a t e -------------
237  //  -- edi: function
238  // -----------------------------------
239  Generate_DebugBreakCallHelper(masm, edi.bit(), 0, false);
240}
241
242
243void Debug::GenerateCallFunctionStubRecordDebugBreak(MacroAssembler* masm) {
244  // Register state for CallFunctionStub (from code-stubs-ia32.cc).
245  // ----------- S t a t e -------------
246  //  -- ebx: cache cell for call target
247  //  -- edi: function
248  // -----------------------------------
249  Generate_DebugBreakCallHelper(masm, ebx.bit() | edi.bit(), 0, false);
250}
251
252
253void Debug::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) {
254  // Register state for CallConstructStub (from code-stubs-ia32.cc).
255  // eax is the actual number of arguments not encoded as a smi see comment
256  // above IC call.
257  // ----------- S t a t e -------------
258  //  -- eax: number of arguments (not smi)
259  //  -- edi: constructor function
260  // -----------------------------------
261  // The number of arguments in eax is not smi encoded.
262  Generate_DebugBreakCallHelper(masm, edi.bit(), eax.bit(), false);
263}
264
265
266void Debug::GenerateCallConstructStubRecordDebugBreak(MacroAssembler* masm) {
267  // Register state for CallConstructStub (from code-stubs-ia32.cc).
268  // eax is the actual number of arguments not encoded as a smi see comment
269  // above IC call.
270  // ----------- S t a t e -------------
271  //  -- eax: number of arguments (not smi)
272  //  -- ebx: cache cell for call target
273  //  -- edi: constructor function
274  // -----------------------------------
275  // The number of arguments in eax is not smi encoded.
276  Generate_DebugBreakCallHelper(masm, ebx.bit() | edi.bit(), eax.bit(), false);
277}
278
279
280void Debug::GenerateSlot(MacroAssembler* masm) {
281  // Generate enough nop's to make space for a call instruction.
282  Label check_codesize;
283  __ bind(&check_codesize);
284  __ RecordDebugBreakSlot();
285  __ Nop(Assembler::kDebugBreakSlotLength);
286  ASSERT_EQ(Assembler::kDebugBreakSlotLength,
287            masm->SizeOfCodeGeneratedSince(&check_codesize));
288}
289
290
291void Debug::GenerateSlotDebugBreak(MacroAssembler* masm) {
292  // In the places where a debug break slot is inserted no registers can contain
293  // object pointers.
294  Generate_DebugBreakCallHelper(masm, 0, 0, true);
295}
296
297
298void Debug::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
299  masm->ret(0);
300}
301
302
303void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
304  ExternalReference restarter_frame_function_slot =
305      ExternalReference(Debug_Address::RestarterFrameFunctionPointer(),
306                        masm->isolate());
307  __ mov(Operand::StaticVariable(restarter_frame_function_slot), Immediate(0));
308
309  // We do not know our frame height, but set esp based on ebp.
310  __ lea(esp, Operand(ebp, -1 * kPointerSize));
311
312  __ pop(edi);  // Function.
313  __ pop(ebp);
314
315  // Load context from the function.
316  __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
317
318  // Get function code.
319  __ mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
320  __ mov(edx, FieldOperand(edx, SharedFunctionInfo::kCodeOffset));
321  __ lea(edx, FieldOperand(edx, Code::kHeaderSize));
322
323  // Re-run JSFunction, edi is function, esi is context.
324  __ jmp(edx);
325}
326
327const bool Debug::kFrameDropperSupported = true;
328
329#undef __
330
331#endif  // ENABLE_DEBUGGER_SUPPORT
332
333} }  // namespace v8::internal
334
335#endif  // V8_TARGET_ARCH_IA32
336