Index: lib/esan/cache_frag.cpp
===================================================================
--- lib/esan/cache_frag.cpp
+++ lib/esan/cache_frag.cpp
@@ -16,14 +16,27 @@
 
 namespace __esan {
 
+// This should be kept consistent with LLVM's EfficiencySanitizer CacheFragType.
+// The tool-specific information per compilation unit (module).
+struct CacheFragType {
+  ToolType WhichTool;
+  const char *UnitName;
+};
+
 //===-- Init/exit functions -----------------------------------------------===//
 
 void processCacheFragCompilationUnitInit(void *Ptr) {
-  VPrintf(2, "in esan::%s\n", __FUNCTION__);
+  CacheFragType *CacheFrag = (CacheFragType *)Ptr;
+  if (CacheFrag->WhichTool != WhichTool)
+    return;
+  VPrintf(2, "in esan::%s: %s\n", __FUNCTION__, CacheFrag->UnitName);
 }
 
 void processCacheFragCompilationUnitExit(void *Ptr) {
-  VPrintf(2, "in esan::%s\n", __FUNCTION__);
+  CacheFragType *CacheFrag = (CacheFragType *)Ptr;
+  if (CacheFrag->WhichTool != WhichTool)
+    return;
+  VPrintf(2, "in esan::%s: %s\n", __FUNCTION__, CacheFrag->UnitName);
 }
 
 void initializeCacheFrag() {
Index: test/esan/TestCases/struct-simple.cpp
===================================================================
--- test/esan/TestCases/struct-simple.cpp
+++ test/esan/TestCases/struct-simple.cpp
@@ -28,17 +28,17 @@
   // CHECK:      in esan::initializeLibrary
   // CHECK-NEXT: in esan::initializeCacheFrag
   // CHECK:      in esan::processCompilationUnitInit
-  // CHECK-NEXT: in esan::processCacheFragCompilationUnitInit
+  // CHECK-NEXT: in esan::processCacheFragCompilationUnitInit: {{.*}}struct-simple.cpp
   // CHECK-NEXT: in esan::processCompilationUnitInit
-  // CHECK-NEXT: in esan::processCacheFragCompilationUnitInit
+  // CHECK-NEXT: in esan::processCacheFragCompilationUnitInit: {{.*}}struct-simple.cpp
   part();
   return 0;
   // CHECK:      in esan::finalizeLibrary
   // CHECK-NEXT: in esan::finalizeCacheFrag
   // CHECK-NEXT: {{.*}}EfficiencySanitizer is not finished: nothing yet to report
   // CHECK-NEXT: in esan::processCompilationUnitExit
-  // CHECK-NEXT: in esan::processCacheFragCompilationUnitExit
+  // CHECK-NEXT: in esan::processCacheFragCompilationUnitExit: {{.*}}struct-simple.cpp
   // CHECK-NEXT: in esan::processCompilationUnitExit
-  // CHECK-NEXT: in esan::processCacheFragCompilationUnitExit
+  // CHECK-NEXT: in esan::processCacheFragCompilationUnitExit: {{.*}}struct-simple.cpp
 }
 #endif // MAIN