1 // Copyright 2012 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
7 #if V8_TARGET_ARCH_IA32
9 #include "src/codegen.h"
10 #include "src/debug.h"
17 // Patch the code at the current PC with a call to the target address.
18 // Additional guard int3 instructions can be added if required.
19 void PatchCodeWithCall(Address pc, Address target, int guard_bytes) {
20 // Call instruction takes up 5 bytes and int3 takes up one byte.
21 static const int kCallCodeSize = 5;
22 int code_size = kCallCodeSize + guard_bytes;
24 // Create a code patcher.
25 CodePatcher patcher(pc, code_size);
27 // Add a label for checking the size of the code used for returning.
30 patcher.masm()->bind(&check_codesize);
34 patcher.masm()->call(target, RelocInfo::NONE32);
36 // Check that the size of the code generated is as expected.
37 DCHECK_EQ(kCallCodeSize,
38 patcher.masm()->SizeOfCodeGeneratedSince(&check_codesize));
40 // Add the requested number of int3 instructions after the call.
41 DCHECK_GE(guard_bytes, 0);
42 for (int i = 0; i < guard_bytes; i++) {
43 patcher.masm()->int3();
46 CpuFeatures::FlushICache(pc, code_size);
50 // Patch the JS frame exit code with a debug break call. See
51 // CodeGenerator::VisitReturnStatement and VirtualFrame::Exit in codegen-ia32.cc
52 // for the precise return instructions sequence.
53 void BreakLocation::SetDebugBreakAtReturn() {
54 DCHECK(Assembler::kJSReturnSequenceLength >=
55 Assembler::kCallInstructionLength);
57 pc(), debug_info_->GetIsolate()->builtins()->Return_DebugBreak()->entry(),
58 Assembler::kJSReturnSequenceLength - Assembler::kCallInstructionLength);
62 void BreakLocation::SetDebugBreakAtSlot() {
63 DCHECK(IsDebugBreakSlot());
64 Isolate* isolate = debug_info_->GetIsolate();
66 pc(), isolate->builtins()->Slot_DebugBreak()->entry(),
67 Assembler::kDebugBreakSlotLength - Assembler::kCallInstructionLength);
71 #define __ ACCESS_MASM(masm)
73 static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
75 RegList non_object_regs,
76 bool convert_call_to_jmp) {
77 // Enter an internal frame.
79 FrameScope scope(masm, StackFrame::INTERNAL);
81 // Load padding words on stack.
82 for (int i = 0; i < LiveEdit::kFramePaddingInitialSize; i++) {
83 __ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingValue)));
85 __ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
87 // Store the registers containing live values on the expression stack to
88 // make sure that these are correctly updated during GC. Non object values
89 // are stored as a smi causing it to be untouched by GC.
90 DCHECK((object_regs & ~kJSCallerSaved) == 0);
91 DCHECK((non_object_regs & ~kJSCallerSaved) == 0);
92 DCHECK((object_regs & non_object_regs) == 0);
93 for (int i = 0; i < kNumJSCallerSaved; i++) {
94 int r = JSCallerSavedCode(i);
96 if ((object_regs & (1 << r)) != 0) {
99 if ((non_object_regs & (1 << r)) != 0) {
100 if (FLAG_debug_code) {
101 __ test(reg, Immediate(0xc0000000));
102 __ Assert(zero, kUnableToEncodeValueAsSmi);
110 __ RecordComment("// Calling from debug break to runtime - come in - over");
112 __ Move(eax, Immediate(0)); // No arguments.
113 __ mov(ebx, Immediate(ExternalReference::debug_break(masm->isolate())));
115 CEntryStub ceb(masm->isolate(), 1);
118 // Automatically find register that could be used after register restore.
119 // We need one register for padding skip instructions.
120 Register unused_reg = { -1 };
122 // Restore the register values containing object pointers from the
124 for (int i = kNumJSCallerSaved; --i >= 0;) {
125 int r = JSCallerSavedCode(i);
126 Register reg = { r };
127 if (FLAG_debug_code) {
128 __ Move(reg, Immediate(kDebugZapValue));
130 bool taken = reg.code() == esi.code();
131 if ((object_regs & (1 << r)) != 0) {
135 if ((non_object_regs & (1 << r)) != 0) {
145 DCHECK(unused_reg.code() != -1);
147 // Read current padding counter and skip corresponding number of words.
149 // We divide stored value by 2 (untagging) and multiply it by word's size.
150 STATIC_ASSERT(kSmiTagSize == 1 && kSmiShiftSize == 0);
151 __ lea(esp, Operand(esp, unused_reg, times_half_pointer_size, 0));
153 // Get rid of the internal frame.
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(esp, Immediate(kPointerSize));
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_after_break_target_address(masm->isolate());
167 __ jmp(Operand::StaticVariable(after_break_target));
171 void DebugCodegen::GenerateCallICStubDebugBreak(MacroAssembler* masm) {
172 // Register state for CallICStub
173 // ----------- S t a t e -------------
174 // -- edx : type feedback slot (smi)
176 // -----------------------------------
177 Generate_DebugBreakCallHelper(masm, edx.bit() | edi.bit(),
182 void DebugCodegen::GenerateLoadICDebugBreak(MacroAssembler* masm) {
183 // Register state for IC load call (from ic-ia32.cc).
184 Register receiver = LoadDescriptor::ReceiverRegister();
185 Register name = LoadDescriptor::NameRegister();
186 RegList regs = receiver.bit() | name.bit();
187 if (FLAG_vector_ics) {
188 regs |= VectorLoadICTrampolineDescriptor::SlotRegister().bit();
190 Generate_DebugBreakCallHelper(masm, regs, 0, false);
194 void DebugCodegen::GenerateStoreICDebugBreak(MacroAssembler* masm) {
195 // Register state for IC store call (from ic-ia32.cc).
196 Register receiver = StoreDescriptor::ReceiverRegister();
197 Register name = StoreDescriptor::NameRegister();
198 Register value = StoreDescriptor::ValueRegister();
199 Generate_DebugBreakCallHelper(
200 masm, receiver.bit() | name.bit() | value.bit(), 0, false);
204 void DebugCodegen::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
205 // Register state for keyed IC load call (from ic-ia32.cc).
206 GenerateLoadICDebugBreak(masm);
210 void DebugCodegen::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
211 // Register state for keyed IC store call (from ic-ia32.cc).
212 Register receiver = StoreDescriptor::ReceiverRegister();
213 Register name = StoreDescriptor::NameRegister();
214 Register value = StoreDescriptor::ValueRegister();
215 Generate_DebugBreakCallHelper(
216 masm, receiver.bit() | name.bit() | value.bit(), 0, false);
220 void DebugCodegen::GenerateCompareNilICDebugBreak(MacroAssembler* masm) {
221 // Register state for CompareNil IC
222 // ----------- S t a t e -------------
224 // -----------------------------------
225 Generate_DebugBreakCallHelper(masm, eax.bit(), 0, false);
229 void DebugCodegen::GenerateReturnDebugBreak(MacroAssembler* masm) {
230 // Register state just before return from JS function (from codegen-ia32.cc).
231 // ----------- S t a t e -------------
232 // -- eax: return value
233 // -----------------------------------
234 Generate_DebugBreakCallHelper(masm, eax.bit(), 0, true);
238 void DebugCodegen::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) {
239 // Register state for CallFunctionStub (from code-stubs-ia32.cc).
240 // ----------- S t a t e -------------
242 // -----------------------------------
243 Generate_DebugBreakCallHelper(masm, edi.bit(), 0, false);
247 void DebugCodegen::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) {
248 // Register state for CallConstructStub (from code-stubs-ia32.cc).
249 // eax is the actual number of arguments not encoded as a smi see comment
251 // ----------- S t a t e -------------
252 // -- eax: number of arguments (not smi)
253 // -- edi: constructor function
254 // -----------------------------------
255 // The number of arguments in eax is not smi encoded.
256 Generate_DebugBreakCallHelper(masm, edi.bit(), eax.bit(), false);
260 void DebugCodegen::GenerateCallConstructStubRecordDebugBreak(
261 MacroAssembler* masm) {
262 // Register state for CallConstructStub (from code-stubs-ia32.cc).
263 // eax is the actual number of arguments not encoded as a smi see comment
265 // ----------- S t a t e -------------
266 // -- eax: number of arguments (not smi)
267 // -- ebx: feedback array
268 // -- edx: feedback slot (smi)
269 // -- edi: constructor function
270 // -----------------------------------
271 // The number of arguments in eax is not smi encoded.
272 Generate_DebugBreakCallHelper(masm, ebx.bit() | edx.bit() | edi.bit(),
277 void DebugCodegen::GenerateSlot(MacroAssembler* masm) {
278 // Generate enough nop's to make space for a call instruction.
279 Label check_codesize;
280 __ bind(&check_codesize);
281 __ RecordDebugBreakSlot();
282 __ Nop(Assembler::kDebugBreakSlotLength);
283 DCHECK_EQ(Assembler::kDebugBreakSlotLength,
284 masm->SizeOfCodeGeneratedSince(&check_codesize));
288 void DebugCodegen::GenerateSlotDebugBreak(MacroAssembler* masm) {
289 // In the places where a debug break slot is inserted no registers can contain
291 Generate_DebugBreakCallHelper(masm, 0, 0, true);
295 void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
300 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
301 ExternalReference restarter_frame_function_slot =
302 ExternalReference::debug_restarter_frame_function_pointer_address(
304 __ mov(Operand::StaticVariable(restarter_frame_function_slot), Immediate(0));
306 // We do not know our frame height, but set esp based on ebp.
307 __ lea(esp, Operand(ebp, -1 * kPointerSize));
309 __ pop(edi); // Function.
312 // Load context from the function.
313 __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
315 // Get function code.
316 __ mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
317 __ mov(edx, FieldOperand(edx, SharedFunctionInfo::kCodeOffset));
318 __ lea(edx, FieldOperand(edx, Code::kHeaderSize));
320 // Re-run JSFunction, edi is function, esi is context.
325 const bool LiveEdit::kFrameDropperSupported = true;
329 } } // namespace v8::internal
331 #endif // V8_TARGET_ARCH_IA32