debug-ia32.cc revision 8b112d2025046f85ef7f6be087c6129c872ebad2 
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  __ EnterInternalFrame();
104
105  // Store the registers containing live values on the expression stack to
106  // make sure that these are correctly updated during GC. Non object values
107  // are stored as a smi causing it to be untouched by GC.
108  ASSERT((object_regs & ~kJSCallerSaved) == 0);
109  ASSERT((non_object_regs & ~kJSCallerSaved) == 0);
110  ASSERT((object_regs & non_object_regs) == 0);
111  for (int i = 0; i < kNumJSCallerSaved; i++) {
112    int r = JSCallerSavedCode(i);
113    Register reg = { r };
114    if ((object_regs & (1 << r)) != 0) {
115      __ push(reg);
116    }
117    if ((non_object_regs & (1 << r)) != 0) {
118      if (FLAG_debug_code) {
119        __ test(reg, Immediate(0xc0000000));
120        __ Assert(zero, "Unable to encode value as smi");
121      }
122      __ SmiTag(reg);
123      __ push(reg);
124    }
125  }
126
127#ifdef DEBUG
128  __ RecordComment("// Calling from debug break to runtime - come in - over");
129#endif
130  __ Set(eax, Immediate(0));  // No arguments.
131  __ mov(ebx, Immediate(ExternalReference::debug_break(masm->isolate())));
132
133  CEntryStub ceb(1);
134  __ CallStub(&ceb);
135
136  // Restore the register values containing object pointers from the expression
137  // stack.
138  for (int i = kNumJSCallerSaved; --i >= 0;) {
139    int r = JSCallerSavedCode(i);
140    Register reg = { r };
141    if (FLAG_debug_code) {
142      __ Set(reg, Immediate(kDebugZapValue));
143    }
144    if ((object_regs & (1 << r)) != 0) {
145      __ pop(reg);
146    }
147    if ((non_object_regs & (1 << r)) != 0) {
148      __ pop(reg);
149      __ SmiUntag(reg);
150    }
151  }
152
153  // Get rid of the internal frame.
154  __ LeaveInternalFrame();
155
156  // If this call did not replace a call but patched other code then there will
157  // be an unwanted return address left on the stack. Here we get rid of that.
158  if (convert_call_to_jmp) {
159    __ add(Operand(esp), Immediate(kPointerSize));
160  }
161
162  // Now that the break point has been handled, resume normal execution by
163  // jumping to the target address intended by the caller and that was
164  // overwritten by the address of DebugBreakXXX.
165  ExternalReference after_break_target =
166      ExternalReference(Debug_Address::AfterBreakTarget(), masm->isolate());
167  __ jmp(Operand::StaticVariable(after_break_target));
168}
169
170
171void Debug::GenerateLoadICDebugBreak(MacroAssembler* masm) {
172  // Register state for IC load call (from ic-ia32.cc).
173  // ----------- S t a t e -------------
174  //  -- eax    : receiver
175  //  -- ecx    : name
176  // -----------------------------------
177  Generate_DebugBreakCallHelper(masm, eax.bit() | ecx.bit(), 0, false);
178}
179
180
181void Debug::GenerateStoreICDebugBreak(MacroAssembler* masm) {
182  // Register state for IC store call (from ic-ia32.cc).
183  // ----------- S t a t e -------------
184  //  -- eax    : value
185  //  -- ecx    : name
186  //  -- edx    : receiver
187  // -----------------------------------
188  Generate_DebugBreakCallHelper(
189      masm, eax.bit() | ecx.bit() | edx.bit(), 0, false);
190}
191
192
193void Debug::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
194  // Register state for keyed IC load call (from ic-ia32.cc).
195  // ----------- S t a t e -------------
196  //  -- edx    : receiver
197  //  -- eax    : key
198  // -----------------------------------
199  Generate_DebugBreakCallHelper(masm, eax.bit() | edx.bit(), 0, false);
200}
201
202
203void Debug::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
204  // Register state for keyed IC load call (from ic-ia32.cc).
205  // ----------- S t a t e -------------
206  //  -- eax    : value
207  //  -- ecx    : key
208  //  -- edx    : receiver
209  // -----------------------------------
210  Generate_DebugBreakCallHelper(
211      masm, eax.bit() | ecx.bit() | edx.bit(), 0, false);
212}
213
214
215void Debug::GenerateCallICDebugBreak(MacroAssembler* masm) {
216  // Register state for keyed IC call call (from ic-ia32.cc)
217  // ----------- S t a t e -------------
218  //  -- ecx: name
219  // -----------------------------------
220  Generate_DebugBreakCallHelper(masm, ecx.bit(), 0, false);
221}
222
223
224void Debug::GenerateConstructCallDebugBreak(MacroAssembler* masm) {
225  // Register state just before return from JS function (from codegen-ia32.cc).
226  // eax is the actual number of arguments not encoded as a smi see comment
227  // above IC call.
228  // ----------- S t a t e -------------
229  //  -- eax: number of arguments (not smi)
230  //  -- edi: constructor function
231  // -----------------------------------
232  // The number of arguments in eax is not smi encoded.
233  Generate_DebugBreakCallHelper(masm, edi.bit(), eax.bit(), false);
234}
235
236
237void Debug::GenerateReturnDebugBreak(MacroAssembler* masm) {
238  // Register state just before return from JS function (from codegen-ia32.cc).
239  // ----------- S t a t e -------------
240  //  -- eax: return value
241  // -----------------------------------
242  Generate_DebugBreakCallHelper(masm, eax.bit(), 0, true);
243}
244
245
246void Debug::GenerateStubNoRegistersDebugBreak(MacroAssembler* masm) {
247  // Register state for stub CallFunction (from CallFunctionStub in ic-ia32.cc).
248  // ----------- S t a t e -------------
249  //  No registers used on entry.
250  // -----------------------------------
251  Generate_DebugBreakCallHelper(masm, 0, 0, false);
252}
253
254
255void Debug::GenerateSlot(MacroAssembler* masm) {
256  // Generate enough nop's to make space for a call instruction.
257  Label check_codesize;
258  __ bind(&check_codesize);
259  __ RecordDebugBreakSlot();
260  for (int i = 0; i < Assembler::kDebugBreakSlotLength; i++) {
261    __ nop();
262  }
263  ASSERT_EQ(Assembler::kDebugBreakSlotLength,
264            masm->SizeOfCodeGeneratedSince(&check_codesize));
265}
266
267
268void Debug::GenerateSlotDebugBreak(MacroAssembler* masm) {
269  // In the places where a debug break slot is inserted no registers can contain
270  // object pointers.
271  Generate_DebugBreakCallHelper(masm, 0, 0, true);
272}
273
274
275void Debug::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
276  masm->ret(0);
277}
278
279
280void Debug::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
281  ExternalReference restarter_frame_function_slot =
282      ExternalReference(Debug_Address::RestarterFrameFunctionPointer(),
283                        masm->isolate());
284  __ mov(Operand::StaticVariable(restarter_frame_function_slot), Immediate(0));
285
286  // We do not know our frame height, but set esp based on ebp.
287  __ lea(esp, Operand(ebp, -1 * kPointerSize));
288
289  __ pop(edi);  // Function.
290  __ pop(ebp);
291
292  // Load context from the function.
293  __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
294
295  // Get function code.
296  __ mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
297  __ mov(edx, FieldOperand(edx, SharedFunctionInfo::kCodeOffset));
298  __ lea(edx, FieldOperand(edx, Code::kHeaderSize));
299
300  // Re-run JSFunction, edi is function, esi is context.
301  __ jmp(Operand(edx));
302}
303
304const bool Debug::kFrameDropperSupported = true;
305
306#undef __
307
308#endif  // ENABLE_DEBUGGER_SUPPORT
309
310} }  // namespace v8::internal
311
312#endif  // V8_TARGET_ARCH_IA32
313