More precise break points and stepping when debugging...

src/ia32/debug-ia32.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 51 matching lines @@
 
 
 // A debug break in the frame exit code is identified by the JS frame exit code
 // having been patched with a call instruction.
 bool Debug::IsDebugBreakAtReturn(RelocInfo* rinfo) {
   ASSERT(RelocInfo::IsJSReturn(rinfo->rmode()));
   return rinfo->IsPatchedReturnSequence();
 }
 
 
+bool BreakLocationIterator::IsDebugBreakAtSlot() {
+  ASSERT(IsDebugBreakSlot());
+  // Check whether the debug break slot instructions have been patched.
+  return rinfo()->IsPatchedDebugBreakSlotSequence();
+}
+
+
+void BreakLocationIterator::SetDebugBreakAtSlot() {
+  ASSERT(IsDebugBreakSlot());
+  rinfo()->PatchCodeWithCall(
+      Debug::debug_break_slot()->entry(),
+      Assembler::kDebugBreakSlotLength - Assembler::kCallInstructionLength);
+}
+
+
+void BreakLocationIterator::ClearDebugBreakAtSlot() {
+  ASSERT(IsDebugBreakSlot());
+  rinfo()->PatchCode(original_rinfo()->pc(), Assembler::kDebugBreakSlotLength);
+}
+
+
 #define __ ACCESS_MASM(masm)
 
 
 static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
                                           RegList pointer_regs,
                                           bool convert_call_to_jmp) {
   // Save the content of all general purpose registers in memory. This copy in
   // memory is later pushed onto the JS expression stack for the fake JS frame
   // generated and also to the C frame generated on top of that. In the JS
   // frame ONLY the registers containing pointers will be pushed on the
@@ skipping 119 matching lines @@
 
 void Debug::GenerateStubNoRegistersDebugBreak(MacroAssembler* masm) {
   // Register state for stub CallFunction (from CallFunctionStub in ic-ia32.cc).
   // ----------- S t a t e -------------
   //  No registers used on entry.
   // -----------------------------------
   Generate_DebugBreakCallHelper(masm, 0, false);
 }
 
 
+void Debug::GenerateSlot(MacroAssembler* masm) {
+  // Generate enough nop's to make space for a call instruction.
+  Label check_codesize;
+  __ bind(&check_codesize);
+  __ RecordDebugBreakSlot();
+  for (int i = 0; i < Assembler::kDebugBreakSlotLength; i++) {
+    __ nop();
+  }
+  ASSERT_EQ(Assembler::kDebugBreakSlotLength,
+            masm->SizeOfCodeGeneratedSince(&check_codesize));
+}
+
+
+void Debug::GenerateSlotDebugBreak(MacroAssembler* masm) {
+  // In the places where a debug break slot is inserted no registers can contain
+  // object pointers.
+  Generate_DebugBreakCallHelper(masm, 0, true);
+}
+
+
 void Debug::GeneratePlainReturnLiveEdit(MacroAssembler* masm) {
   masm->ret(0);
 }
 
+
 // FrameDropper is a code replacement for a JavaScript frame with possibly
 // several frames above.
 // There is no calling conventions here, because it never actually gets called,
 // it only gets returned to.
 // Frame structure (conforms InternalFrame structure):
 //   -- JSFunction
 //   -- code
 //   -- SMI maker
 //   -- context
 //   -- frame base
@@ skipping 33 matching lines @@
   Memory::Object_at(fp - 2 * kPointerSize) = Smi::FromInt(StackFrame::INTERNAL);
 }
 const int Debug::kFrameDropperFrameSize = 5;
 
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32