[ubsan] Drop terminal "in " from reports without functions (#77163)

Author: vitalybuka

compiler-rt/lib/ubsan/ubsan_diag.cpp

@@ -88,7 +88,7 @@ static void MaybeReportErrorSummary(Location Loc, ErrorType Type) {
       AI.file = internal_strdup(SLoc.getFilename());
       AI.line = SLoc.getLine();
       AI.column = SLoc.getColumn();
-      AI.function = internal_strdup("");  // Avoid printing ?? as function name.
+      AI.function = nullptr;
       ReportErrorSummary(ErrorKind, AI, GetSanititizerToolName());
       AI.Clear();
       return;

compiler-rt/test/ubsan/TestCases/Misc/print_summary.c

@@ -2,8 +2,8 @@
 // RUN: %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-DEFAULT
 // RUN: %env_ubsan_opts=print_summary=0 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-NO_SUMMARY
 
-// CHECK-DEFAULT: SUMMARY: UndefinedBehaviorSanitizer: {{.*}}
-// CHECK-NO_SUMMARY-NOT: SUMMARY: UndefinedBehaviorSanitizer: {{.*}}
+// CHECK-DEFAULT: SUMMARY: UndefinedBehaviorSanitizer: {{.*}}print_summary.c{{[:0-9 ]*$}}
+// CHECK-NO_SUMMARY-NOT: SUMMARY: UndefinedBehaviorSanitizer:
 
 int main(int argc, char **argv) {
   int arr[argc - 2];