Add support for HitCount and HitCondition (#1548)

* Add support for HitCount and HitCondition

This PR adds in showing the Hit count for a breakpoint and for setting a
HitCondition.

Enables m_supportsHitConditionalBreakpoints, OpenDebugAD7 now properly
builds a AD7BreakpointRequest with a hitCondition, AD7BoundBreakpoint
now properly tracks hits and will prevent a break event if theres a
condition set.

Added CppTests and updated DebuggerTesting for associated commands.

Addresses: #472

* Use -break-after

* Handle updating hitCondition when with hitCount > 0

* Address PR issues

* Re-add ShouldBreak()

Author: WardenGnaw

src/MICore/CommandFactories/MICommandFactory.cs

@@ -567,6 +567,15 @@ public virtual async Task BreakCondition(string bkptno, string expr)
             await _debugger.CmdAsync(command, ResultClass.done);
         }
 
+        /// <summary>
+        /// Sends -break-after to set an ignore count on a breakpoint.
+        /// </summary>
+        public virtual async Task<Results> BreakAfter(string bkptno, uint count)
+        {
+            string command = string.Format(CultureInfo.InvariantCulture, "-break-after {0} {1}", bkptno, count);
+            return await _debugger.CmdAsync(command, ResultClass.done);
+        }
+
         public virtual IEnumerable<Guid> GetSupportedExceptionCategories()
         {
             return new Guid[0];

src/MIDebugEngine/AD7.Impl/AD7BoundBreakpoint.cs

@@ -5,6 +5,7 @@
 using Microsoft.VisualStudio.Debugger.Interop;
 using System;
 using System.Diagnostics;
+using System.Threading.Tasks;
 
 namespace Microsoft.MIDebugEngine
 {
@@ -19,6 +20,8 @@ internal class AD7BoundBreakpoint : IDebugBoundBreakpoint2
         private BoundBreakpoint _bp;
 
         private bool _deleted;
+        private enum_BP_PASSCOUNT_STYLE _passCountStyle;
+        private uint _passCountValue;
 
         internal bool Enabled
         {
@@ -37,6 +40,7 @@ internal bool Enabled
         internal string Number { get { return _bp.Number; } }
         internal AD7PendingBreakpoint PendingBreakpoint { get { return _pendingBreakpoint; } }
         internal bool IsDataBreakpoint { get { return PendingBreakpoint.IsDataBreakpoint; } }
+        internal bool HasPassCount { get { return _passCountStyle != enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_NONE; } }
 
         public AD7BoundBreakpoint(AD7Engine engine, AD7PendingBreakpoint pendingBreakpoint, AD7BreakpointResolution breakpointResolution, BoundBreakpoint bp)
         {
@@ -143,8 +147,7 @@ int IDebugBoundBreakpoint2.GetState(enum_BP_STATE[] pState)
             return Constants.S_OK;
         }
 
-        // The sample engine does not support hit counts on breakpoints. A real-world debugger will want to keep track 
-        // of how many times a particular bound breakpoint has been hit and return it here.
+        // Returns the number of times this breakpoint has been hit.
         int IDebugBoundBreakpoint2.GetHitCount(out uint pdwHitCount)
         {
             pdwHitCount = _bp.HitCount;
@@ -156,29 +159,91 @@ int IDebugBoundBreakpoint2.SetCondition(BP_CONDITION bpCondition)
             return ((IDebugPendingBreakpoint2)_pendingBreakpoint).SetCondition(bpCondition);  // setting on the pending break will set the condition
         }
 
-        // The sample engine does not support hit counts on breakpoints. A real-world debugger will want to keep track 
-        // of how many times a particular bound breakpoint has been hit. The debugger calls SetHitCount when the user 
-        // resets a breakpoint's hit count.
+        // Called by the debugger when the user resets a breakpoint's hit count.
         int IDebugBoundBreakpoint2.SetHitCount(uint dwHitCount)
         {
-            throw new NotImplementedException();
+            _bp.SetHitCount(dwHitCount);
+            _pendingBreakpoint?.RecomputeBreakAfter(dwHitCount);
+
+            return Constants.S_OK;
+        }
+
+        /// <summary>
+        /// Syncs the hit count from GDB's "times" field using a delta
+        /// to preserve any user-initiated hit count reset.
+        /// </summary>
+        internal void SetHitCount(uint hitCount)
+        {
+            _bp.SetGdbHitCount(hitCount);
         }
 
-        // The sample engine does not support pass counts on breakpoints.
         // This is used to specify the breakpoint hit count condition.
         int IDebugBoundBreakpoint2.SetPassCount(BP_PASSCOUNT bpPassCount)
         {
-            if (bpPassCount.stylePassCount != enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_NONE)
-            {
-                Delete();
-                _engine.Callback.OnBreakpointUnbound(this, enum_BP_UNBOUND_REASON.BPUR_BREAKPOINT_ERROR);
-                return Constants.E_FAIL;
-            }
+            _passCountStyle = bpPassCount.stylePassCount;
+            _passCountValue = bpPassCount.dwPassCount;
             return Constants.S_OK;
         }
 
         #endregion
 
+        internal uint HitCount => _bp.HitCount;
+
+        internal void IncrementHitCount()
+        {
+            _bp.IncrementHitCount();
+        }
+
+        /// <summary>
+        /// Evaluates whether the debugger should break at this breakpoint based on the
+        /// current hit count and the configured pass count condition.
+        /// Must be called after IncrementHitCount.
+        /// </summary>
+        internal bool ShouldBreak()
+        {
+            uint hitCount = _bp.HitCount;
+            switch (_passCountStyle)
+            {
+                case enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_NONE:
+                    return true;
+                case enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_EQUAL:
+                    return hitCount == _passCountValue;
+                case enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_EQUAL_OR_GREATER:
+                    return hitCount >= _passCountValue;
+                case enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_MOD:
+                    return _passCountValue != 0 && (hitCount % _passCountValue) == 0;
+                default:
+                    return true;
+            }
+        }
+
+        /// <summary>
+        /// Re-sends -break-after to GDB after a pass count breakpoint fires.
+        /// MOD: skips passCount-1 hits. EQUAL: clears the ignore count.
+        /// </summary>
+        internal async Task RearmBreakAfterAsync()
+        {
+            uint ignoreCount;
+            switch (_passCountStyle)
+            {
+                case enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_MOD:
+                    if (_passCountValue == 0) return;
+                    ignoreCount = _passCountValue - 1;
+                    break;
+                case enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_EQUAL:
+                    ignoreCount = 0;
+                    break;
+                default:
+                    return;
+            }
+
+            PendingBreakpoint bp = _pendingBreakpoint?.PendingBreakpoint;
+            if (bp != null && _engine?.DebuggedProcess != null)
+            {
+                await bp.SetBreakAfterAsync(ignoreCount, _engine.DebuggedProcess);
+            }
+        }
+
         internal void UpdateAddr(ulong addr)
         {
             _bp.Addr = addr;

src/MIDebugEngine/AD7.Impl/AD7PendingBreakpoint.cs

@@ -115,11 +115,6 @@ private bool CanBind()
                     return false;
                 }
             }
-            if ((_bpRequestInfo.dwFields & enum_BPREQI_FIELDS.BPREQI_PASSCOUNT) != 0)
-            {
-                this.SetError(new AD7ErrorBreakpoint(this, ResourceStrings.UnsupportedPassCountBreakpoint, enum_BP_ERROR_TYPE.BPET_GENERAL_ERROR));
-                return false;
-            }
 
             return true;
         }
@@ -393,6 +388,40 @@ internal async Task BindAsync()
                         }
                     }
                 }
+
+                // Set ignore count via -break-after if a pass count is configured
+                if (_bp != null && (_bpRequestInfo.dwFields & enum_BPREQI_FIELDS.BPREQI_PASSCOUNT) != 0
+                    && _bpRequestInfo.bpPassCount.stylePassCount != enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_NONE)
+                {
+                    uint ignoreCount = ComputeIgnoreCount(_bpRequestInfo.bpPassCount.stylePassCount, _bpRequestInfo.bpPassCount.dwPassCount, 0);
+                    await _bp.SetBreakAfterAsync(ignoreCount, _engine.DebuggedProcess);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Computes the ignore count for -break-after, accounting for hits already
+        /// counted from a prior breakpoint (<paramref name="currentHits"/>).
+        /// </summary>
+        private static uint ComputeIgnoreCount(enum_BP_PASSCOUNT_STYLE style, uint passCount, uint currentHits)
+        {
+            if (passCount == 0)
+            {
+                return 0;
+            }
+
+            switch (style)
+            {
+                case enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_EQUAL:
+                case enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_EQUAL_OR_GREATER:
+                    // Need to stop at hit N. Already counted currentHits, so skip (N - 1 - currentHits) more.
+                    return passCount - 1 > currentHits ? passCount - 1 - currentHits : 0;
+                case enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_MOD:
+                    // Next stop is at the next multiple of passCount after currentHits.
+                    uint remainder = currentHits % passCount;
+                    return remainder == 0 ? passCount - 1 : passCount - 1 - remainder;
+                default:
+                    return 0;
             }
         }
 
@@ -406,6 +435,11 @@ internal AD7BoundBreakpoint AddBoundBreakpoint(BoundBreakpoint bp)
                 }
                 AD7BreakpointResolution breakpointResolution = new AD7BreakpointResolution(_engine, IsDataBreakpoint, bp.Addr, bp.FunctionName, bp.DocumentContext(_engine));
                 AD7BoundBreakpoint boundBreakpoint = new AD7BoundBreakpoint(_engine, this, breakpointResolution, bp);
+                // Apply pass count (hit count condition) from the original request to the bound breakpoint
+                if ((_bpRequestInfo.dwFields & enum_BPREQI_FIELDS.BPREQI_PASSCOUNT) != 0)
+                {
+                    ((IDebugBoundBreakpoint2)boundBreakpoint).SetPassCount(_bpRequestInfo.bpPassCount);
+                }
                 //check can bind one last time. If the pending breakpoint was deleted before now, we need to clean up gdb side
                 if (CanBind())
                 {
@@ -645,17 +679,77 @@ int IDebugPendingBreakpoint2.SetCondition(BP_CONDITION bpCondition)
             return Constants.S_OK;
         }
 
-        // The sample engine does not support pass counts on breakpoints.
         int IDebugPendingBreakpoint2.SetPassCount(BP_PASSCOUNT bpPassCount)
         {
-            if (bpPassCount.stylePassCount != enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_NONE)
+            _bpRequestInfo.bpPassCount = bpPassCount;
+            _bpRequestInfo.dwFields |= enum_BPREQI_FIELDS.BPREQI_PASSCOUNT;
+
+            PendingBreakpoint bp = null;
+            lock (_boundBreakpoints)
             {
-                this.SetError(new AD7ErrorBreakpoint(this, ResourceStrings.UnsupportedPassCountBreakpoint, enum_BP_ERROR_TYPE.BPET_GENERAL_ERROR), true);
-                return Constants.E_FAIL;
+                foreach (AD7BoundBreakpoint boundBp in _boundBreakpoints)
+                {
+                    ((IDebugBoundBreakpoint2)boundBp).SetPassCount(bpPassCount);
+                }
+                if (_bp != null)
+                {
+                    bp = _bp;
+                }
+            }
+
+            // When the pass count is cleared (NONE), send ignore count 0 to clear
+            // any stale GDB ignore count from the previous condition.
+            if (bp != null)
+            {
+                uint ignoreCount = 0;
+                if (bpPassCount.stylePassCount != enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_NONE)
+                {
+                    uint currentHits = 0;
+                    lock (_boundBreakpoints)
+                    {
+                        foreach (AD7BoundBreakpoint boundBp in _boundBreakpoints)
+                        {
+                            uint hc;
+                            if (((IDebugBoundBreakpoint2)boundBp).GetHitCount(out hc) == Constants.S_OK && hc > currentHits)
+                            {
+                                currentHits = hc;
+                            }
+                        }
+                    }
+                    ignoreCount = ComputeIgnoreCount(bpPassCount.stylePassCount, bpPassCount.dwPassCount, currentHits);
+                }
+                _engine.DebuggedProcess.WorkerThread.RunOperation(() =>
+                {
+                    _engine.DebuggedProcess.AddInternalBreakAction(
+                        () => bp.SetBreakAfterAsync(ignoreCount, _engine.DebuggedProcess)
+                    );
+                });
             }
             return Constants.S_OK;
         }
 
+        /// <summary>
+        /// Re-sends -break-after to GDB after a hit count reset.
+        /// </summary>
+        internal void RecomputeBreakAfter(uint currentHits)
+        {
+            if (_bp == null
+                || (_bpRequestInfo.dwFields & enum_BPREQI_FIELDS.BPREQI_PASSCOUNT) == 0
+                || _bpRequestInfo.bpPassCount.stylePassCount == enum_BP_PASSCOUNT_STYLE.BP_PASSCOUNT_NONE)
+            {
+                return;
+            }
+
+            PendingBreakpoint bp = _bp;
+            uint ignoreCount = ComputeIgnoreCount(_bpRequestInfo.bpPassCount.stylePassCount, _bpRequestInfo.bpPassCount.dwPassCount, currentHits);
+            _engine.DebuggedProcess.WorkerThread.RunOperation(() =>
+            {
+                _engine.DebuggedProcess.AddInternalBreakAction(
+                    () => bp.SetBreakAfterAsync(ignoreCount, _engine.DebuggedProcess)
+                );
+            });
+        }
+
         // Toggles the virtualized state of this pending breakpoint. When a pending breakpoint is virtualized, 
         // the debug engine will attempt to bind it every time new code loads into the program.
         // The sample engine will does not support this.

src/MIDebugEngine/Engine.Impl/BreakpointManager.cs

@@ -71,6 +71,30 @@ public async Task BreakpointModified(object sender, EventArgs args)
                 return;
             }
 
+            // Sync GDB's hit count ("times") for pass count breakpoints.
+            // e.g. =breakpoint-modified,bkpt={number="1",...,times="5",ignore="2",...}
+            string timesStr = bkpt.TryFindString("times");
+            if (!string.IsNullOrEmpty(timesStr) && uint.TryParse(timesStr, out uint times))
+            {
+                foreach (AD7BoundBreakpoint boundBp in pending.EnumBoundBreakpoints())
+                {
+                    if (boundBp.HasPassCount)
+                    {
+                        uint previousHitCount = boundBp.HitCount;
+                        boundBp.SetHitCount(times);
+
+                        // Re-arm GDB's ignore count so it skips to the next target hit.
+                        // HitCount guard: -break-after itself triggers =breakpoint-modified.
+                        // ShouldBreak guard: GDB also emits =breakpoint-modified on ignored
+                        //   hits, and re-arming then would shift the next stop.
+                        if (boundBp.HitCount != previousHitCount && boundBp.ShouldBreak())
+                        {
+                            await boundBp.RearmBreakAfterAsync();
+                        }
+                    }
+                }
+            }
+
             string warning = bkpt.TryFindString("warning");
             if (!string.IsNullOrEmpty(warning))
             {
@@ -212,7 +236,15 @@ public AD7BoundBreakpoint[] FindHitBreakpoints(string bkptno, ulong addr, /*OPTI
                     continue;
                 }
 
-                hitBoundBreakpoints.Add(currBoundBp);
+                // Pass count breakpoints get their hit count from =breakpoint-modified.
+                if (!currBoundBp.HasPassCount)
+                {
+                    currBoundBp.IncrementHitCount();
+                }
+                if (currBoundBp.ShouldBreak())
+                {
+                    hitBoundBreakpoints.Add(currBoundBp);
+                }
             }
 
             fContinue = (hitBoundBreakpoints.Count == 0 && hitBps.Length != 0);