From cd0116ccde70e08e66e6532277c7c4fab1b0b1cc Mon Sep 17 00:00:00 2001
From: aldelaro5 <aldelaro5@gmail.com>
Date: Thu, 15 Sep 2016 22:32:28 -0400
Subject: [PATCH] Fix a bunch of debugger stepping issues.

Single step: Fix an oddity when a breakpoint is hit at the beginning of a block, then after, a single step is performed and finally, hitting play, the breakpoint will be skipped even in the case when it would be hit again.  This was done by using the interpreter version of single step.  Also, remove some redundant update request.

Step over: fix some GUI lags.

Step out: Add consideration for conditional branching by checking the condition as the interpreter does.  Now, every bclr instructions except those that changes the LR (because it would not be the end of the function) will cause the end of the step out and not just blr instructions.  Also now stops if a bp is detected and finally, remove redundant GUI updates calls.

This also removes a superfluous draw call on the GUI as the codeView was refreshing twice per event to do so.
---
 Source/Core/DolphinWX/Debugger/CodeWindow.cpp | 50 ++++++++++---------
 1 file changed, 26 insertions(+), 24 deletions(-)

diff --git a/Source/Core/DolphinWX/Debugger/CodeWindow.cpp b/Source/Core/DolphinWX/Debugger/CodeWindow.cpp
index 2f1ba3aaa7..aff5d48577 100644
--- a/Source/Core/DolphinWX/Debugger/CodeWindow.cpp
+++ b/Source/Core/DolphinWX/Debugger/CodeWindow.cpp
@@ -149,8 +149,6 @@ void CCodeWindow::OnHostMessage(wxCommandEvent& event)
 
   case IDM_UPDATE_DISASM_DIALOG:
     Update();
-    if (codeview)
-      codeview->Center(PC);
     if (CPU::IsStepping())
       Parent->UpdateGUI();
     if (m_RegisterWindow)
@@ -160,7 +158,6 @@ void CCodeWindow::OnHostMessage(wxCommandEvent& event)
     break;
 
   case IDM_UPDATE_BREAKPOINTS:
-    Update();
     if (m_BreakpointWindow)
       m_BreakpointWindow->NotifyUpdate();
     break;
@@ -296,13 +293,13 @@ void CCodeWindow::SingleStep()
 {
   if (CPU::IsStepping())
   {
+    PowerPC::CoreMode old_mode = PowerPC::GetMode();
+    PowerPC::SetMode(PowerPC::MODE_INTERPRETER);
     PowerPC::breakpoints.ClearAllTemporary();
-    JitInterface::InvalidateICache(PC, 4, true);
     CPU::StepOpcode(&sync_event);
-    wxThread::Sleep(20);
-    // need a short wait here
-    JumpToAddress(PC);
-    Update();
+    sync_event.WaitFor(std::chrono::milliseconds(20));
+    PowerPC::SetMode(old_mode);
+    // Will get a IDM_UPDATE_DISASM_DIALOG. Don't update the GUI here.
   }
 }
 
@@ -316,20 +313,23 @@ void CCodeWindow::StepOver()
       PowerPC::breakpoints.ClearAllTemporary();
       PowerPC::breakpoints.Add(PC + 4, true);
       CPU::EnableStepping(false);
-      JumpToAddress(PC);
-      Update();
     }
     else
     {
       SingleStep();
     }
-
-    UpdateButtonStates();
-    // Update all toolbars in the aui manager
-    Parent->UpdateGUI();
   }
 }
 
+// Returns true on a blr or on a bclr that evaluates to true.
+static bool WillInstructionReturn(UGeckoInstruction inst)
+{
+  bool counter = (inst.BO_2 >> 2 & 1) != 0 || (CTR != 0) != ((inst.BO_2 >> 1 & 1) != 0);
+  bool condition = inst.BO_2 >> 4 != 0 || GetCRBit(inst.BI_2) == (inst.BO_2 >> 3 & 1);
+  bool isBclr = inst.OPCD_7 == 0b010011 && (inst.hex >> 1 & 0b10000) != 0;
+  return isBclr && counter && condition && !inst.LK_3;
+}
+
 void CCodeWindow::StepOut()
 {
   if (CPU::IsStepping())
@@ -337,13 +337,16 @@ void CCodeWindow::StepOut()
     CPU::PauseAndLock(true, false);
     PowerPC::breakpoints.ClearAllTemporary();
 
-    // Keep stepping until the next blr or timeout after one second
+    // Keep stepping until the next return instruction or timeout after one second
     u64 timeout = SystemTimers::GetTicksPerSecond();
     u64 steps = 0;
-    PowerPC::CoreMode oldMode = PowerPC::GetMode();
+    PowerPC::CoreMode old_mode = PowerPC::GetMode();
     PowerPC::SetMode(PowerPC::MODE_INTERPRETER);
     UGeckoInstruction inst = PowerPC::HostRead_Instruction(PC);
-    while (inst.hex != 0x4e800020 && steps < timeout)  // check for blr
+    // Loop until either the current instruction is a return instruction with no Link flag
+    // or a breakpoint is detected so it can step at the breakpoint.
+    while (!(WillInstructionReturn(inst)) && steps < timeout &&
+           !PowerPC::breakpoints.IsAddressBreakPoint(PC))
     {
       if (inst.LK)
       {
@@ -362,15 +365,14 @@ void CCodeWindow::StepOut()
       }
       inst = PowerPC::HostRead_Instruction(PC);
     }
-
-    PowerPC::SingleStep();
-    PowerPC::SetMode(oldMode);
+    // If the loop stopped because of a breakpoint, we do not want to step to
+    // an instruction after it.
+    if (!PowerPC::breakpoints.IsAddressBreakPoint(PC))
+      PowerPC::SingleStep();
+    PowerPC::SetMode(old_mode);
     CPU::PauseAndLock(false, false);
 
-    JumpToAddress(PC);
-    Update();
     Host_UpdateDisasmDialog();
-
     UpdateButtonStates();
     // Update all toolbars in the aui manager
     Parent->UpdateGUI();
@@ -698,7 +700,7 @@ void CCodeWindow::Update()
   if (!codeview)
     return;
 
-  codeview->Refresh();
+  codeview->Center(PC);
   UpdateCallstack();
   UpdateButtonStates();