Fix BadImageFormatException that occurred when trace annotations were used in conjunction with DD_TRACE_DEBUG (#4045)

* Fix memory corruption that happened due to a buffer that went out of scope prematurely

* Enable DD_TRACE_DEBUG in Trace Annotations integration tests

Author: OmerRaviv

tracer/src/Datadog.Tracer.Native/method_rewriter.cpp

@@ -111,6 +111,11 @@ HRESULT TracerMethodRewriter::Rewrite(RejitHandlerModule* moduleHandler, RejitHa
     bool isStatic = !(caller->method_signature.CallingConvention() & IMAGE_CEE_CS_CALLCONV_HASTHIS);
     std::vector<trace::TypeSignature> methodArguments = caller->method_signature.GetMethodArguments();
     std::vector<trace::TypeSignature> traceAnnotationArguments;
+
+    // DO NOT move the definition of these buffers into an inner scope. It will cause memory corruption since they are referenced in a TypeSignature that is used later in this function.
+    COR_SIGNATURE runtimeMethodHandleBuffer[10];
+    COR_SIGNATURE runtimeTypeHandleBuffer[10];
+
     int numArgs = caller->method_signature.NumberOfArguments();
     auto metaEmit = module_metadata.metadata_emit;
     auto metaImport = module_metadata.metadata_import;
@@ -307,9 +312,6 @@ HRESULT TracerMethodRewriter::Rewrite(RejitHandlerModule* moduleHandler, RejitHa
     }
     else
     {
-        COR_SIGNATURE runtimeMethodHandleBuffer[10];
-        COR_SIGNATURE runtimeTypeHandleBuffer[10];
-
         // Load the methodDef token to produce a RuntimeMethodHandle on the stack
         reWriterWrapper.LoadToken(caller->id);
 

tracer/test/Datadog.Trace.ClrProfiler.IntegrationTests/TraceAnnotationsTests.cs

@@ -86,7 +86,7 @@ public async Task SubmitTraces()
             ddTraceMethodsString += ";Samples.TraceAnnotations.ExtensionMethods[ExtensionMethodForTestType,ExtensionMethodForTestTypeGeneric,ExtensionMethodForTestTypeTypeStruct];System.Net.Http.HttpRequestMessage[set_Method]";
 
             SetEnvironmentVariable("DD_TRACE_METHODS", ddTraceMethodsString);
-
+            SetEnvironmentVariable("DD_TRACE_DEBUG", "1");
             // Don't bother with telemetry when two assemblies are loaded because we could get unreliable results
             MockTelemetryAgent<TelemetryData> telemetry = _twoAssembliesLoaded ? null : this.ConfigureTelemetry();
             using (var agent = EnvironmentHelper.GetMockAgent())