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.
9 #include "src/codegen.h"
10 #include "src/debug.h"
16 // Patch the code at the current PC with a call to the target address.
17 // Additional guard int3 instructions can be added if required.
18 void PatchCodeWithCall(Address pc, Address target, int guard_bytes) {
19 // Call instruction takes up 5 bytes and int3 takes up one byte.
20 static const int kCallCodeSize = 5;
21 int code_size = kCallCodeSize + guard_bytes;
23 // Create a code patcher.
24 CodePatcher patcher(pc, code_size);
26 // Add a label for checking the size of the code used for returning.
29 patcher.masm()->bind(&check_codesize);
33 patcher.masm()->call(target, RelocInfo::NONE32);
35 // Check that the size of the code generated is as expected.
36 DCHECK_EQ(kCallCodeSize,
37 patcher.masm()->SizeOfCodeGeneratedSince(&check_codesize));
39 // Add the requested number of int3 instructions after the call.
40 DCHECK_GE(guard_bytes, 0);
41 for (int i = 0; i < guard_bytes; i++) {
42 patcher.masm()->int3();
45 CpuFeatures::FlushICache(pc, code_size);
49 // Patch the JS frame exit code with a debug break call. See
50 // CodeGenerator::VisitReturnStatement and VirtualFrame::Exit in codegen-x87.cc
51 // for the precise return instructions sequence.
52 void BreakLocation::SetDebugBreakAtReturn() {
53 DCHECK(Assembler::kJSReturnSequenceLength >=
54 Assembler::kCallInstructionLength);
56 pc(), debug_info_->GetIsolate()->builtins()->Return_DebugBreak()->entry(),
57 Assembler::kJSReturnSequenceLength - Assembler::kCallInstructionLength);
61 void BreakLocation::SetDebugBreakAtSlot() {
62 DCHECK(IsDebugBreakSlot());
63 Isolate* isolate = debug_info_->GetIsolate();
65 pc(), isolate->builtins()->Slot_DebugBreak()->entry(),
66 Assembler::kDebugBreakSlotLength - Assembler::kCallInstructionLength);
70 #define __ ACCESS_MASM(masm)
72 static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
74 RegList non_object_regs,
75 bool convert_call_to_jmp) {
76 // Enter an internal frame.
78 FrameScope scope(masm, StackFrame::INTERNAL);
80 // Load padding words on stack.
81 for (int i = 0; i < LiveEdit::kFramePaddingInitialSize; i++) {
82 __ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingValue)));
84 __ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingInitialSize)));
86 // Store the registers containing live values on the expression stack to
87 // make sure that these are correctly updated during GC. Non object values
88 // are stored as a smi causing it to be untouched by GC.
89 DCHECK((object_regs & ~kJSCallerSaved) == 0);
90 DCHECK((non_object_regs & ~kJSCallerSaved) == 0);
91 DCHECK((object_regs & non_object_regs) == 0);
92 for (int i = 0; i < kNumJSCallerSaved; i++) {
93 int r = JSCallerSavedCode(i);
95 if ((object_regs & (1 << r)) != 0) {
98 if ((non_object_regs & (1 << r)) != 0) {
99 if (FLAG_debug_code) {
100 __ test(reg, Immediate(0xc0000000));
101 __ Assert(zero, kUnableToEncodeValueAsSmi);
109 __ RecordComment("// Calling from debug break to runtime - come in - over");
111 __ Move(eax, Immediate(0)); // No arguments.
112 __ mov(ebx, Immediate(ExternalReference::debug_break(masm->isolate())));
114 CEntryStub ceb(masm->isolate(), 1);
117 // Automatically find register that could be used after register restore.
118 // We need one register for padding skip instructions.
119 Register unused_reg = { -1 };
121 // Restore the register values containing object pointers from the
123 for (int i = kNumJSCallerSaved; --i >= 0;) {
124 int r = JSCallerSavedCode(i);
125 Register reg = { r };
126 if (FLAG_debug_code) {
127 __ Move(reg, Immediate(kDebugZapValue));
129 bool taken = reg.code() == esi.code();
130 if ((object_regs & (1 << r)) != 0) {
134 if ((non_object_regs & (1 << r)) != 0) {
144 DCHECK(unused_reg.code() != -1);
146 // Read current padding counter and skip corresponding number of words.
148 // We divide stored value by 2 (untagging) and multiply it by word's size.
149 STATIC_ASSERT(kSmiTagSize == 1 && kSmiShiftSize == 0);
150 __ lea(esp, Operand(esp, unused_reg, times_half_pointer_size, 0));
152 // Get rid of the internal frame.
155 // If this call did not replace a call but patched other code then there will
156 // be an unwanted return address left on the stack. Here we get rid of that.
157 if (convert_call_to_jmp) {
158 __ add(esp, Immediate(kPointerSize));
161 // Now that the break point has been handled, resume normal execution by
162 // jumping to the target address intended by the caller and that was
163 // overwritten by the address of DebugBreakXXX.
164 ExternalReference after_break_target =
165 ExternalReference::debug_after_break_target_address(masm->isolate());
166 __ jmp(Operand::StaticVariable(after_break_target));
170 void DebugCodegen::GenerateCallICStubDebugBreak(MacroAssembler* masm) {
171 // Register state for CallICStub
172 // ----------- S t a t e -------------
173 // -- edx : type feedback slot (smi)
175 // -----------------------------------
176 Generate_DebugBreakCallHelper(masm, edx.bit() | edi.bit(),
181 void DebugCodegen::GenerateLoadICDebugBreak(MacroAssembler* masm) {
182 // Register state for IC load call (from ic-x87.cc).
183 Register receiver = LoadDescriptor::ReceiverRegister();
184 Register name = LoadDescriptor::NameRegister();
185 RegList regs = receiver.bit() | name.bit();
186 if (FLAG_vector_ics) {
187 regs |= VectorLoadICTrampolineDescriptor::SlotRegister().bit();
189 Generate_DebugBreakCallHelper(masm, regs, 0, false);
193 void DebugCodegen::GenerateStoreICDebugBreak(MacroAssembler* masm) {
194 // Register state for IC store call (from ic-x87.cc).
195 Register receiver = StoreDescriptor::ReceiverRegister();
196 Register name = StoreDescriptor::NameRegister();
197 Register value = StoreDescriptor::ValueRegister();
198 Generate_DebugBreakCallHelper(
199 masm, receiver.bit() | name.bit() | value.bit(), 0, false);
203 void DebugCodegen::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) {
204 // Register state for keyed IC load call (from ic-x87.cc).
205 GenerateLoadICDebugBreak(masm);
209 void DebugCodegen::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) {
210 // Register state for keyed IC store call (from ic-x87.cc).
211 Register receiver = StoreDescriptor::ReceiverRegister();
212 Register name = StoreDescriptor::NameRegister();
213 Register value = StoreDescriptor::ValueRegister();
214 Generate_DebugBreakCallHelper(
215 masm, receiver.bit() | name.bit() | value.bit(), 0, false);
219 void DebugCodegen::GenerateCompareNilICDebugBreak(MacroAssembler* masm) {
220 // Register state for CompareNil IC
221 // ----------- S t a t e -------------
223 // -----------------------------------
224 Generate_DebugBreakCallHelper(masm, eax.bit(), 0, false);
228 void DebugCodegen::GenerateReturnDebugBreak(MacroAssembler* masm) {
229 // Register state just before return from JS function (from codegen-x87.cc).
230 // ----------- S t a t e -------------
231 // -- eax: return value
232 // -----------------------------------
233 Generate_DebugBreakCallHelper(masm, eax.bit(), 0, true);
237 void DebugCodegen::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) {
238 // Register state for CallFunctionStub (from code-stubs-x87.cc).
239 // ----------- S t a t e -------------
241 // -----------------------------------
242 Generate_DebugBreakCallHelper(masm, edi.bit(), 0, false);
246 void DebugCodegen::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) {
247 // Register state for CallConstructStub (from code-stubs-x87.cc).
248 // eax is the actual number of arguments not encoded as a smi see comment
250 // ----------- S t a t e -------------
251 // -- eax: number of arguments (not smi)
252 // -- edi: constructor function
253 // -----------------------------------
254 // The number of arguments in eax is not smi encoded.
255 Generate_DebugBreakCallHelper(masm, edi.bit(), eax.bit(), false);
259 void DebugCodegen::GenerateCallConstructStubRecordDebugBreak(
260 MacroAssembler* masm) {
261 // Register state for CallConstructStub (from code-stubs-x87.cc).
262 // eax is the actual number of arguments not encoded as a smi see comment
264 // ----------- S t a t e -------------
265 // -- eax: number of arguments (not smi)
266 // -- ebx: feedback array
267 // -- edx: feedback slot (smi)
268 // -- edi: constructor function
269 // -----------------------------------
270 // The number of arguments in eax is not smi encoded.
271 Generate_DebugBreakCallHelper(masm, ebx.bit() | edx.bit() | edi.bit(),
276 void DebugCodegen::GenerateSlot(MacroAssembler* masm) {
277 // Generate enough nop's to make space for a call instruction.
278 Label check_codesize;
279 __ bind(&check_codesize);
280 __ RecordDebugBreakSlot();
281 __ Nop(Assembler::kDebugBreakSlotLength);
282 DCHECK_EQ(Assembler::kDebugBreakSlotLength,
283 masm->SizeOfCodeGeneratedSince(&check_codesize));
287 void DebugCodegen::GenerateSlotDebugBreak(MacroAssembler* masm) {
288 // In the places where a debug break slot is inserted no registers can contain
290 Generate_DebugBreakCallHelper(masm, 0, 0, true);
294 void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
299 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) {
300 ExternalReference restarter_frame_function_slot =
301 ExternalReference::debug_restarter_frame_function_pointer_address(
303 __ mov(Operand::StaticVariable(restarter_frame_function_slot), Immediate(0));
305 // We do not know our frame height, but set esp based on ebp.
306 __ lea(esp, Operand(ebp, -1 * kPointerSize));
308 __ pop(edi); // Function.
311 // Load context from the function.
312 __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
314 // Get function code.
315 __ mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
316 __ mov(edx, FieldOperand(edx, SharedFunctionInfo::kCodeOffset));
317 __ lea(edx, FieldOperand(edx, Code::kHeaderSize));
319 // Re-run JSFunction, edi is function, esi is context.
324 const bool LiveEdit::kFrameDropperSupported = true;
328 } } // namespace v8::internal
330 #endif // V8_TARGET_ARCH_X87