From 263281a2f0f6eeea80849a9616bb94e31ffd7ea5 Mon Sep 17 00:00:00 2001
From: kudzu_cp <6d05c8c8ef5431987001abfdb2eadc9593ac9498>
Date: Sun, 12 Aug 2012 15:29:07 +0000
Subject: [PATCH] Faster stepping.

---
 .../AD7.Impl/AD7Process.cs                    |  5 +-
 .../AD7.Impl/AD7Thread.cs                     | 64 +++++++++++--------
 2 files changed, 41 insertions(+), 28 deletions(-)

diff --git a/source2/Debug/Cosmos.Debug.VSDebugEngine/AD7.Impl/AD7Process.cs b/source2/Debug/Cosmos.Debug.VSDebugEngine/AD7.Impl/AD7Process.cs
index e0d242aee..f0fe9467b 100644
--- a/source2/Debug/Cosmos.Debug.VSDebugEngine/AD7.Impl/AD7Process.cs
+++ b/source2/Debug/Cosmos.Debug.VSDebugEngine/AD7.Impl/AD7Process.cs
@@ -25,7 +25,9 @@ namespace Cosmos.Debug.VSDebugEngine {
     protected readonly NameValueCollection mDebugInfo;
     protected LaunchType mLaunch;
     internal DebugInfo mDebugInfoDb;
-    private int mProcessExitEventSent = 0;
+    protected int mProcessExitEventSent = 0;
+    // Cached stack frame. See comments in AD7Thread regading this.
+    public IEnumDebugFrameInfo2 mStackFrame;
 
     // Connection to target environment. Usually serial but is
     // abstracted to allow other transports (ethernet, etc)
@@ -261,6 +263,7 @@ namespace Cosmos.Debug.VSDebugEngine {
         }
       }
 
+      mStackFrame = null;
       mCurrentAddress = aAddress;
       if (xBoundBreakpoints.Count == 0) {
         // if no matching breakpoints are found then its one of the following:
diff --git a/source2/Debug/Cosmos.Debug.VSDebugEngine/AD7.Impl/AD7Thread.cs b/source2/Debug/Cosmos.Debug.VSDebugEngine/AD7.Impl/AD7Thread.cs
index f4b40f462..9ec413892 100644
--- a/source2/Debug/Cosmos.Debug.VSDebugEngine/AD7.Impl/AD7Thread.cs
+++ b/source2/Debug/Cosmos.Debug.VSDebugEngine/AD7.Impl/AD7Thread.cs
@@ -9,10 +9,10 @@ using Cosmos.Debug.Common;
 namespace Cosmos.Debug.VSDebugEngine {
   // This class implements IDebugThread2 which represents a thread running in a program.
   public class AD7Thread : IDebugThread2 {
-    readonly AD7Engine mEngine;
+    protected readonly AD7Engine mEngine;
+    protected readonly AD7Process mProcess;
     //readonly DebuggedThread m_debuggedThread;
     const string ThreadNameString = "Cosmos Kernel Main Thread";
-    protected AD7Process mProcess;
 
     public AD7Thread(AD7Engine aEngine, AD7Process aProcess) { //, DebuggedThread debuggedThread)
       mEngine = aEngine;
@@ -38,35 +38,45 @@ namespace Cosmos.Debug.VSDebugEngine {
     // Real engines will most likely want to cache this information to avoid recomputing it each time it is asked for,
     // and or construct it on demand instead of walking the entire stack.
     int IDebugThread2.EnumFrameInfo(enum_FRAMEINFO_FLAGS aFieldSpec, uint aRadix, out IEnumDebugFrameInfo2 oEnumObject) {
-      // Ask the lower-level to perform a stack walk on this thread
-      //m_engine.DebuggedProcess.DoStackWalk(this.m_debuggedThread);
-      oEnumObject = null;
-      try {
-        //System.Collections.Generic.List<X86ThreadContext> stackFrames = this.m_debuggedThread.StackFrames;
-        //int numStackFrames = stackFrames.Count;
-        FRAMEINFO[] xFrameInfoArray;
+      // Check mStackFrame, not address because it is possible for 2 sequential breaks to be on the same address
+      // but in that case we would need a new stack frame.
+      //
+      // EnumFrameInfo is called several times on each break becuase "different callers can call with different flags".
+      // We ignore flags through and always return full, but EnumFrameInfo gets called half a dozen times which is slow
+      // if we refresh each and every time. So we cache our info.
+      if (mProcess.mStackFrame == null) {
+        // Ask the lower-level to perform a stack walk on this thread
+        //m_engine.DebuggedProcess.DoStackWalk(this.m_debuggedThread);
+        oEnumObject = null;
+        try {
+          //System.Collections.Generic.List<X86ThreadContext> stackFrames = this.m_debuggedThread.StackFrames;
+          //int numStackFrames = stackFrames.Count;
+          FRAMEINFO[] xFrameInfoArray;
 
-        //if (numStackFrames == 0) {
-        // failed to walk any frames. Only return the top frame.
-        xFrameInfoArray = new FRAMEINFO[1];
-        AD7StackFrame xFrame = new AD7StackFrame(mEngine, this, mProcess);
-        xFrame.SetFrameInfo((enum_FRAMEINFO_FLAGS)aFieldSpec, out xFrameInfoArray[0]);
-        //} else {
-        //frameInfoArray = new FRAMEINFO[numStackFrames];
+          //if (numStackFrames == 0) {
+          // failed to walk any frames. Only return the top frame.
 
-        //for (int i = 0; i < numStackFrames; i++) {
-        //AD7StackFrame frame = new AD7StackFrame(m_engine, this, stackFrames[i]);
-        //frame.SetFrameInfo(dwFieldSpec, out frameInfoArray[i]);
-        //}
-        //}
+          xFrameInfoArray = new FRAMEINFO[1];
+          var xFrame = new AD7StackFrame(mEngine, this, mProcess);
+          xFrame.SetFrameInfo((enum_FRAMEINFO_FLAGS)aFieldSpec, out xFrameInfoArray[0]);
 
-        oEnumObject = new AD7FrameInfoEnum(xFrameInfoArray);
-      } catch (Exception e) {
-        //catch (ComponentException e) {
-        //    return e.HResult;
-        //}
-        return EngineUtils.UnexpectedException(e);
+          //} else {
+          //frameInfoArray = new FRAMEINFO[numStackFrames];
+          //for (int i = 0; i < numStackFrames; i++) {
+          //AD7StackFrame frame = new AD7StackFrame(m_engine, this, stackFrames[i]);
+          //frame.SetFrameInfo(dwFieldSpec, out frameInfoArray[i]);
+          //}
+          //}
+
+          mProcess.mStackFrame = new AD7FrameInfoEnum(xFrameInfoArray);
+        } catch (Exception e) {
+          //catch (ComponentException e) {
+          //    return e.HResult;
+          //}
+          return EngineUtils.UnexpectedException(e);
+        }
       }
+      oEnumObject = mProcess.mStackFrame;
       return VSConstants.S_OK;
     }