Fix cdbstack parser dropping last sample and missing metrics

src/PerfView.Tests/DebuggerStackSourceTests.cs

@@ -0,0 +1,78 @@
+using Diagnostics.Tracing.StackSources;
+using Microsoft.Diagnostics.Tracing.Stacks;
+using System.IO;
+using Xunit;
+
+namespace PerfViewTests
+{
+    public class DebuggerStackSourceTests
+    {
+        [Fact]
+        public void TestLastSampleIsNotDropped()
+        {
+            // Create a sample cdbstack file with two samples
+            var cdbStackContent = @"Call Site
+coreclr!JIT_MonEnterWorker_Portable
+System_Windows_ni!MS.Internal.ManagedPeerTable.TryGetManagedPeer(IntPtr, Boolean, System.Object ByRef)
+Call Site
+kernel32!BaseThreadInitThunk
+ntdll!RtlUserThreadStart";
+
+            DebuggerStackSource stackSource;
+            using (var reader = new StringReader(cdbStackContent))
+            {
+                stackSource = new DebuggerStackSource(reader);
+            }
+
+            // Count the samples
+            int sampleCount = 0;
+            stackSource.ForEach(sample => sampleCount++);
+
+            // We should have 2 samples, but the bug causes only 1 to be added
+            Assert.Equal(2, sampleCount);
+        }
+
+        [Fact]
+        public void TestSingleSampleIsAdded()
+        {
+            // Create a sample cdbstack file with a single sample (no subsequent "Call Site")
+            var cdbStackContent = @"Call Site
+coreclr!JIT_MonEnterWorker_Portable
+System_Windows_ni!MS.Internal.ManagedPeerTable.TryGetManagedPeer(IntPtr, Boolean, System.Object ByRef)";
+
+            DebuggerStackSource stackSource;
+            using (var reader = new StringReader(cdbStackContent))
+            {
+                stackSource = new DebuggerStackSource(reader);
+            }
+
+            // Count the samples
+            int sampleCount = 0;
+            stackSource.ForEach(sample => sampleCount++);
+
+            // We should have 1 sample
+            Assert.Equal(1, sampleCount);
+        }
+
+        [Fact]
+        public void TestSampleMetricIsSet()
+        {
+            // Create a sample cdbstack file with one sample
+            var cdbStackContent = @"Call Site
+coreclr!JIT_MonEnterWorker_Portable
+System_Windows_ni!MS.Internal.ManagedPeerTable.TryGetManagedPeer(IntPtr, Boolean, System.Object ByRef)";
+
+            DebuggerStackSource stackSource;
+            using (var reader = new StringReader(cdbStackContent))
+            {
+                stackSource = new DebuggerStackSource(reader);
+            }
+
+            // Check that metric is set to 1 for each sample
+            stackSource.ForEach(sample =>
+            {
+                Assert.Equal(1, sample.Metric);
+            });
+        }
+    }
+}

src/PerfView/OtherSources/DebuggerStackSource.cs

@@ -30,6 +30,23 @@ private struct DebuggerCallStackFrame
             public StackSourceFrameIndex frame;
         }
 
+        private void AddSampleFromStack(GrowableArray<DebuggerCallStackFrame> stack, StackSourceSample sample, ref float time)
+        {
+            StackSourceCallStackIndex parent = StackSourceCallStackIndex.Invalid;
+            for (int i = stack.Count - 1; i >= 0; --i)
+            {
+                parent = Interner.CallStackIntern(stack[i].frame, parent);
+            }
+
+            stack.Clear();
+
+            sample.Metric = 1;
+            sample.StackIndex = parent;
+            sample.TimeRelativeMSec = time;
+            time++;
+            AddSample(sample);
+        }
+
         private void Read(TextReader reader)
         {
             var framePattern = new Regex(@"\b(\w+?)\!(\S\(?[\S\s]*\)?)");
@@ -93,25 +110,20 @@ private void Read(TextReader reader)
                         // clear the stack
                         if (stack.Count != 0)
                         {
-
-                            StackSourceCallStackIndex parent = StackSourceCallStackIndex.Invalid;
-                            for (int i = stack.Count - 1; i >= 0; --i)
-                            {
-                                parent = Interner.CallStackIntern(stack[i].frame, parent);
-                            }
-
-                            stack.Clear();
-
-                            sample.StackIndex = parent;
-                            sample.TimeRelativeMSec = time;
-                            time++;
-                            AddSample(sample);
+                            AddSampleFromStack(stack, sample, ref time);
                         }
                         newCallStackFound = true;
 
                     }
                 }
             }
+
+            // Handle the last sample if there are any remaining frames
+            if (stack.Count != 0)
+            {
+                AddSampleFromStack(stack, sample, ref time);
+            }
+
             Interner.DoneInterning();
         }
         #endregion