Threading fixes (#2618)

* Resolve task invocation issue that prevented effective parallelism.

* Update release notes.

src/ReleaseHistory.md

@@ -11,6 +11,8 @@
 * BRK: For `Guid` properties defined in SARIF spec, updated Json schema to use `uuid`, and updated C# object model to use `Guid?` instead of `string`. [#2555](https://github.com/microsoft/sarif-sdk/pull/2555)
 * BRK: Mark `AnalyzeCommandBase` as obsolete. This type will be removed in the next significant update.  [#2599](https://github.com/microsoft/sarif-sdk/pull/2599)
 * BRK: `LogUnhandledEngineException` no longer has a return value (and updates the `RuntimeErrors` context property directly as other helpers do).  [#2599](https://github.com/microsoft/sarif-sdk/pull/2599)
+* BUG: Populate missing context region data for small, single-line scan targets. [#2616](https://github.com/microsoft/sarif-sdk/pull/2616)
+* BUG: Increase parallelism in `MultithreadedAnalyzeCommandBase` by correcting task creation. []#2618](https://github.com/microsoft/sarif-sdk/pull/2618)
 * BUG: Resolve hangs due to unhandled exceptions during multithreaded analysis file enumeration phase.  [#2599](https://github.com/microsoft/sarif-sdk/pull/2599)
 * BUG: Resolve hangs due to unhandled exceptions during multithreaded analysis file hashing phase.  [#2600](https://github.com/microsoft/sarif-sdk/pull/2600)
 * BUG: Another attempt to resolve 'InvalidOperationException' with message `Collection was modified; enumeration operation may not execute` in `MultithreadedAnalyzeCommandBase`, raised when analyzing with the `--hashes` switch. [#2459](https://github.com/microsoft/sarif-sdk/pull/2549). There was a previous attempt to fix this in [#2447](https://github.com/microsoft/sarif-sdk/pull/2447).

src/Sarif.Driver/Sdk/MultithreadedAnalyzeCommandBase.cs

@@ -218,20 +218,20 @@ private void MultithreadedAnalyzeTargets(TOptions options,
 
             // 1: First we initiate an asynchronous operation to locate disk files for
             // analysis, as specified in analysis configuration (file names, wildcards).
-            Task<bool> enumerateFilesOnDisk = EnumerateFilesOnDiskAsync(options);
+            Task<bool> enumerateFilesOnDisk = Task.Run(() => EnumerateFilesOnDiskAsync(options));
 
             // 2: Files found on disk are put in a specific sort order, after which a 
             // reference to each scan target is put into a channel for hashing,
             // if hashing is enabled.
-            Task<bool> hashFilesAndPutInAnalysisQueue = HashFilesAndPutInAnalysisQueueAsnc();
+            Task<bool> hashFilesAndPutInAnalysisQueue = Task.Run(() => HashFilesAndPutInAnalysisQueueAsnc());
 
             // 3: A dedicated set of threads pull scan targets and analyze them.
             //    On completing a scan, the thread writes the index of the 
             //    scanned item to a channel that drives logging.
             var workers = new Task<bool>[options.Threads];
             for (int i = 0; i < options.Threads; i++)
             {
-                workers[i] = ScanTargetsAsync(skimmers, disabledSkimmers);
+                workers[i] = Task.Run(() => ScanTargetsAsync(skimmers, disabledSkimmers));
             }
 
             // 4: A single-threaded consumer watches for completed scans
@@ -240,7 +240,7 @@ private void MultithreadedAnalyzeTargets(TOptions options,
             //    scan of the same targets using the same production code
             //    should produce a log file that is byte-for-byte identical
             //    to the previous output.
-            Task<bool> logScanResults = LogScanResultsAsync(rootContext);
+            Task<bool> logScanResults = Task.Run(() => LogScanResultsAsync(rootContext));
 
             Task.WhenAll(workers)
                 .ContinueWith(_ => _resultsWritingChannel.Writer.Complete())

src/Sarif/Writers/SarifLogger.cs

@@ -261,7 +261,7 @@ private void EnhanceRun(IEnumerable<string> analysisTargets,
 
         public Func<Uri, HashData> ComputeHashData { get; set; }
 
-        public IDictionary<string, HashData> AnalysisTargetToHashDataMap { get; }
+        public IDictionary<string, HashData> AnalysisTargetToHashDataMap { get; set; }
 
         public IDictionary<ReportingDescriptor, ReportingDescriptorReference> RuleToReportingDescriptorReferenceMap { get; }