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. 4 5 #include "src/v8.h" 6 7 #if V8_TARGET_ARCH_IA32 8 9 #include "src/codegen.h" 10 #include "src/debug.h" 11 12 13 namespace v8 { 14 namespace internal { 15 16 bool BreakLocationIterator::IsDebugBreakAtReturn() { 17 return Debug::IsDebugBreakAtReturn(rinfo()); 18 } 19 20 21 // Patch the JS frame exit code with a debug break call. See 22 // CodeGenerator::VisitReturnStatement and VirtualFrame::Exit in codegen-ia32.cc 23 // for the precise return instructions sequence. 24 void BreakLocationIterator::SetDebugBreakAtReturn() { 25 ASSERT(Assembler::kJSReturnSequenceLength >= 26 Assembler::kCallInstructionLength); 27 rinfo()->PatchCodeWithCall( 28 debug_info_->GetIsolate()->builtins()->Return_DebugBreak()->entry(), 29 Assembler::kJSReturnSequenceLength - Assembler::kCallInstructionLength); 30 } 31 32 33 // Restore the JS frame exit code. 34 void BreakLocationIterator::ClearDebugBreakAtReturn() { 35 rinfo()->PatchCode(original_rinfo()->pc(), 36 Assembler::kJSReturnSequenceLength); 37 } 38 39 40 // A debug break in the frame exit code is identified by the JS frame exit code 41 // having been patched with a call instruction. 42 bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) { 43 ASSERT(RelocInfo::IsJSReturn(rinfo->rmode())); 44 return rinfo->IsPatchedReturnSequence(); 45 } 46 47 48 bool BreakLocationIterator::IsDebugBreakAtSlot() { 49 ASSERT(IsDebugBreakSlot()); 50 // Check whether the debug break slot instructions have been patched. 51 return rinfo()->IsPatchedDebugBreakSlotSequence(); 52 } 53 54 55 void BreakLocationIterator::SetDebugBreakAtSlot() { 56 ASSERT(IsDebugBreakSlot()); 57 Isolate* isolate = debug_info_->GetIsolate(); 58 rinfo()->PatchCodeWithCall( 59 isolate->builtins()->Slot_DebugBreak()->entry(), 60 Assembler::kDebugBreakSlotLength - Assembler::kCallInstructionLength); 61 } 62 63 64 void BreakLocationIterator::ClearDebugBreakAtSlot() { 65 ASSERT(IsDebugBreakSlot()); 66 rinfo()->PatchCode(original_rinfo()->pc(), Assembler::kDebugBreakSlotLength); 67 } 68 69 70 #define __ ACCESS_MASM(masm) 71 72 static void Generate_DebugBreakCallHelper(MacroAssembler* masm, 73 RegList object_regs, 74 RegList non_object_regs, 75 bool convert_call_to_jmp) { 76 // Enter an internal frame. 77 { 78 FrameScope scope(masm, StackFrame::INTERNAL); 79 80 // Load padding words on stack. 81 for (int i = 0; i < LiveEdit::kFramePaddingInitialSize; i++) { 82 __ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingValue))); 83 } 84 __ push(Immediate(Smi::FromInt(LiveEdit::kFramePaddingInitialSize))); 85 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 ASSERT((object_regs & ~kJSCallerSaved) == 0); 90 ASSERT((non_object_regs & ~kJSCallerSaved) == 0); 91 ASSERT((object_regs & non_object_regs) == 0); 92 for (int i = 0; i < kNumJSCallerSaved; i++) { 93 int r = JSCallerSavedCode(i); 94 Register reg = { r }; 95 if ((object_regs & (1 << r)) != 0) { 96 __ push(reg); 97 } 98 if ((non_object_regs & (1 << r)) != 0) { 99 if (FLAG_debug_code) { 100 __ test(reg, Immediate(0xc0000000)); 101 __ Assert(zero, kUnableToEncodeValueAsSmi); 102 } 103 __ SmiTag(reg); 104 __ push(reg); 105 } 106 } 107 108 #ifdef DEBUG 109 __ RecordComment("// Calling from debug break to runtime - come in - over"); 110 #endif 111 __ Move(eax, Immediate(0)); // No arguments. 112 __ mov(ebx, Immediate(ExternalReference::debug_break(masm->isolate()))); 113 114 CEntryStub ceb(masm->isolate(), 1); 115 __ CallStub(&ceb); 116 117 // Automatically find register that could be used after register restore. 118 // We need one register for padding skip instructions. 119 Register unused_reg = { -1 }; 120 121 // Restore the register values containing object pointers from the 122 // expression stack. 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)); 128 } 129 bool taken = reg.code() == esi.code(); 130 if ((object_regs & (1 << r)) != 0) { 131 __ pop(reg); 132 taken = true; 133 } 134 if ((non_object_regs & (1 << r)) != 0) { 135 __ pop(reg); 136 __ SmiUntag(reg); 137 taken = true; 138 } 139 if (!taken) { 140 unused_reg = reg; 141 } 142 } 143 144 ASSERT(unused_reg.code() != -1); 145 146 // Read current padding counter and skip corresponding number of words. 147 __ pop(unused_reg); 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)); 151 152 // Get rid of the internal frame. 153 } 154 155 // 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)); 159 } 160 161 // 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)); 167 } 168 169 170 void DebugCodegen::GenerateCallICStubDebugBreak(MacroAssembler* masm) { 171 // Register state for CallICStub 172 // ----------- S t a t e ------------- 173 // -- edx : type feedback slot (smi) 174 // -- edi : function 175 // ----------------------------------- 176 Generate_DebugBreakCallHelper(masm, edx.bit() | edi.bit(), 177 0, false); 178 } 179 180 181 void DebugCodegen::GenerateLoadICDebugBreak(MacroAssembler* masm) { 182 // Register state for IC load call (from ic-ia32.cc). 183 // ----------- S t a t e ------------- 184 // -- ecx : name 185 // -- edx : receiver 186 // ----------------------------------- 187 Generate_DebugBreakCallHelper(masm, ecx.bit() | edx.bit(), 0, false); 188 } 189 190 191 void DebugCodegen::GenerateStoreICDebugBreak(MacroAssembler* masm) { 192 // Register state for IC store call (from ic-ia32.cc). 193 // ----------- S t a t e ------------- 194 // -- eax : value 195 // -- ecx : name 196 // -- edx : receiver 197 // ----------------------------------- 198 Generate_DebugBreakCallHelper( 199 masm, eax.bit() | ecx.bit() | edx.bit(), 0, false); 200 } 201 202 203 void DebugCodegen::GenerateKeyedLoadICDebugBreak(MacroAssembler* masm) { 204 // Register state for keyed IC load call (from ic-ia32.cc). 205 // ----------- S t a t e ------------- 206 // -- ecx : key 207 // -- edx : receiver 208 // ----------------------------------- 209 Generate_DebugBreakCallHelper(masm, ecx.bit() | edx.bit(), 0, false); 210 } 211 212 213 void DebugCodegen::GenerateKeyedStoreICDebugBreak(MacroAssembler* masm) { 214 // Register state for keyed IC load call (from ic-ia32.cc). 215 // ----------- S t a t e ------------- 216 // -- eax : value 217 // -- ecx : key 218 // -- edx : receiver 219 // ----------------------------------- 220 Generate_DebugBreakCallHelper( 221 masm, eax.bit() | ecx.bit() | edx.bit(), 0, false); 222 } 223 224 225 void DebugCodegen::GenerateCompareNilICDebugBreak(MacroAssembler* masm) { 226 // Register state for CompareNil IC 227 // ----------- S t a t e ------------- 228 // -- eax : value 229 // ----------------------------------- 230 Generate_DebugBreakCallHelper(masm, eax.bit(), 0, false); 231 } 232 233 234 void DebugCodegen::GenerateReturnDebugBreak(MacroAssembler* masm) { 235 // Register state just before return from JS function (from codegen-ia32.cc). 236 // ----------- S t a t e ------------- 237 // -- eax: return value 238 // ----------------------------------- 239 Generate_DebugBreakCallHelper(masm, eax.bit(), 0, true); 240 } 241 242 243 void DebugCodegen::GenerateCallFunctionStubDebugBreak(MacroAssembler* masm) { 244 // Register state for CallFunctionStub (from code-stubs-ia32.cc). 245 // ----------- S t a t e ------------- 246 // -- edi: function 247 // ----------------------------------- 248 Generate_DebugBreakCallHelper(masm, edi.bit(), 0, false); 249 } 250 251 252 void DebugCodegen::GenerateCallConstructStubDebugBreak(MacroAssembler* masm) { 253 // Register state for CallConstructStub (from code-stubs-ia32.cc). 254 // eax is the actual number of arguments not encoded as a smi see comment 255 // above IC call. 256 // ----------- S t a t e ------------- 257 // -- eax: number of arguments (not smi) 258 // -- edi: constructor function 259 // ----------------------------------- 260 // The number of arguments in eax is not smi encoded. 261 Generate_DebugBreakCallHelper(masm, edi.bit(), eax.bit(), false); 262 } 263 264 265 void DebugCodegen::GenerateCallConstructStubRecordDebugBreak( 266 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: feedback array 273 // -- edx: feedback slot (smi) 274 // -- edi: constructor function 275 // ----------------------------------- 276 // The number of arguments in eax is not smi encoded. 277 Generate_DebugBreakCallHelper(masm, ebx.bit() | edx.bit() | edi.bit(), 278 eax.bit(), false); 279 } 280 281 282 void DebugCodegen::GenerateSlot(MacroAssembler* masm) { 283 // Generate enough nop's to make space for a call instruction. 284 Label check_codesize; 285 __ bind(&check_codesize); 286 __ RecordDebugBreakSlot(); 287 __ Nop(Assembler::kDebugBreakSlotLength); 288 ASSERT_EQ(Assembler::kDebugBreakSlotLength, 289 masm->SizeOfCodeGeneratedSince(&check_codesize)); 290 } 291 292 293 void DebugCodegen::GenerateSlotDebugBreak(MacroAssembler* masm) { 294 // In the places where a debug break slot is inserted no registers can contain 295 // object pointers. 296 Generate_DebugBreakCallHelper(masm, 0, 0, true); 297 } 298 299 300 void DebugCodegen::GeneratePlainReturnLiveEdit(MacroAssembler* masm) { 301 masm->ret(0); 302 } 303 304 305 void DebugCodegen::GenerateFrameDropperLiveEdit(MacroAssembler* masm) { 306 ExternalReference restarter_frame_function_slot = 307 ExternalReference::debug_restarter_frame_function_pointer_address( 308 masm->isolate()); 309 __ mov(Operand::StaticVariable(restarter_frame_function_slot), Immediate(0)); 310 311 // We do not know our frame height, but set esp based on ebp. 312 __ lea(esp, Operand(ebp, -1 * kPointerSize)); 313 314 __ pop(edi); // Function. 315 __ pop(ebp); 316 317 // Load context from the function. 318 __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset)); 319 320 // Get function code. 321 __ mov(edx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset)); 322 __ mov(edx, FieldOperand(edx, SharedFunctionInfo::kCodeOffset)); 323 __ lea(edx, FieldOperand(edx, Code::kHeaderSize)); 324 325 // Re-run JSFunction, edi is function, esi is context. 326 __ jmp(edx); 327 } 328 329 330 const bool LiveEdit::kFrameDropperSupported = true; 331 332 #undef __ 333 334 } } // namespace v8::internal 335 336 #endif // V8_TARGET_ARCH_IA32 337