Index: lib/esan/cache_frag.cpp
===================================================================
--- lib/esan/cache_frag.cpp
+++ lib/esan/cache_frag.cpp
@@ -16,14 +16,22 @@
 
 namespace __esan {
 
+// This should be kept consistent with LLVM's EfficiencySanitizer CacheFragInfo.
+// The tool-specific information per compilation unit (module).
+struct CacheFragInfo {
+  const char *UnitName;
+};
+
 //===-- Init/exit functions -----------------------------------------------===//
 
 void processCacheFragCompilationUnitInit(void *Ptr) {
-  VPrintf(2, "in esan::%s\n", __FUNCTION__);
+  CacheFragInfo *CFI = (CacheFragInfo *)Ptr;
+  VPrintf(2, "in esan::%s: %s\n", __FUNCTION__, CFI->UnitName);
 }
 
 void processCacheFragCompilationUnitExit(void *Ptr) {
-  VPrintf(2, "in esan::%s\n", __FUNCTION__);
+  CacheFragInfo *CFI = (CacheFragInfo *)Ptr;
+  VPrintf(2, "in esan::%s: %s\n", __FUNCTION__, CFI->UnitName);
 }
 
 void initializeCacheFrag() {
Index: lib/esan/esan.cpp
===================================================================
--- lib/esan/esan.cpp
+++ lib/esan/esan.cpp
@@ -194,8 +194,16 @@
   return 0;
 }
 
+// Struct with general tool information passed to the runtime.
+// This structure should be kept consistent with the LLVM's EfficiencySanitizer
+// ToolInfo.
+struct ToolInfo {
+  const char *UnitName;
+};
+
 void processCompilationUnitInit(void *Ptr) {
-  VPrintf(2, "in esan::%s\n", __FUNCTION__);
+  ToolInfo *Info = (ToolInfo *)Ptr;
+  VPrintf(2, "in esan::%s: %s\n", __FUNCTION__, Info->UnitName);
   if (WhichTool == ESAN_CacheFrag) {
     processCacheFragCompilationUnitInit(Ptr);
   }
@@ -204,7 +212,8 @@
 // This is called when the containing module is unloaded.
 // For the main executable module, this is called after finalizeLibrary.
 void processCompilationUnitExit(void *Ptr) {
-  VPrintf(2, "in esan::%s\n", __FUNCTION__);
+  ToolInfo *Info = (ToolInfo *)Ptr;
+  VPrintf(2, "in esan::%s: %s\n", __FUNCTION__, Info->UnitName);
   if (WhichTool == ESAN_CacheFrag) {
     processCacheFragCompilationUnitExit(Ptr);
   }
Index: test/esan/TestCases/struct-simple.cpp
===================================================================
--- test/esan/TestCases/struct-simple.cpp
+++ test/esan/TestCases/struct-simple.cpp
@@ -27,18 +27,18 @@
 int main(int argc, char **argv) {
   // CHECK:      in esan::initializeLibrary
   // CHECK:      in esan::initializeCacheFrag
-  // CHECK-NEXT: in esan::processCompilationUnitInit
-  // CHECK-NEXT: in esan::processCacheFragCompilationUnitInit
-  // CHECK-NEXT: in esan::processCompilationUnitInit
-  // CHECK-NEXT: in esan::processCacheFragCompilationUnitInit
+  // CHECK-NEXT: in esan::processCompilationUnitInit: {{.*}}struct-simple.cpp
+  // CHECK-NEXT: in esan::processCacheFragCompilationUnitInit: {{.*}}struct-simple.cpp
+  // CHECK-NEXT: in esan::processCompilationUnitInit: {{.*}}struct-simple.cpp
+  // 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::processCompilationUnitExit
-  // CHECK-NEXT: in esan::processCacheFragCompilationUnitExit
+  // CHECK-NEXT: in esan::processCompilationUnitExit: {{.*}}struct-simple.cpp
+  // CHECK-NEXT: in esan::processCacheFragCompilationUnitExit: {{.*}}struct-simple.cpp
+  // CHECK-NEXT: in esan::processCompilationUnitExit: {{.*}}struct-simple.cpp
+  // CHECK-NEXT: in esan::processCacheFragCompilationUnitExit: {{.*}}struct-simple.cpp
 }
 #endif // MAIN