[dsymutil] Remove empty reproducer directory on exit

[keith]

Summary

In the case the reproducer isn't generated, we don't want to leave
around an empty temporary directory.

Fixes https://github.com/llvm/llvm-project/issues/61920

[JDevlieghere]

Coincidentally, I discovered the same bug last Friday :-) Another alternative would be to create the directory when we decide to emit the reproducer, but I went with the current apporach to limit the amount of work done in the signal handler.

LGTM. Thanks for fixing this!

llvm/test/tools/dsymutil/X86/reproducer.test

 # UNSUPPORTED: system-windows
 # This test is unsupported on windows because it creates paths
 # longer than MAX_PATH
 
 # Recreate the folder structure in a temp directory we can remove later.
 RUN: rm -rf %t
-RUN: mkdir -p %t/Inputs
+RUN: mkdir -p %t/Inputs %t/tempdir
 RUN: cp %p/../Inputs/basic.macho.x86_64 %t/Inputs
 RUN: cp %p/../Inputs/basic1.macho.x86_64.o %t/Inputs
 RUN: cp %p/../Inputs/basic2.macho.x86_64.o %t/Inputs
 RUN: cp %p/../Inputs/basic3.macho.x86_64.o %t/Inputs
 
 # Verify all the files are present.
 RUN: dsymutil -f -o - -oso-prepend-path=%t %t/Inputs/basic.macho.x86_64 | llvm-dwarfdump -a - | FileCheck %s
 
 # Make sure we don't crash with an empty TMPDIR.
 RUN: env TMPDIR="" dsymutil -o -f -oso-prepend-path=%t %t/Inputs/basic.macho.x86_64 2>&1
 
+# Make sure we don't leave around a temporary directory.
+RUN: env TMPDIR="%t/tempdir" dsymutil -o - -f %t/Inputs/basic.macho.x86_64
+RUN: not ls %t/tempdir/dsymutil-*
+
 # Create a reproducer.
 RUN: env DSYMUTIL_REPRODUCER_PATH=%t.repro dsymutil -gen-reproducer -f -o %t.generate -oso-prepend-path=%t %t/Inputs/basic.macho.x86_64 2>&1 | FileCheck %s --check-prefixes=REPRODUCER
 RUN: llvm-dwarfdump -a %t.generate | FileCheck %s
 
 # Remove the input files and verify that was successful.
 RUN: rm -rf %t
 RUN: not dsymutil -f -o %t.error -oso-prepend-path=%t %t/Inputs/basic.macho.x86_64 2>&1 | FileCheck %s --check-prefix=ERROR
 

llvm/tools/dsymutil/Reproducer.cpp

ReproducerGenerate::ReproducerGenerate(std::error_code &EC, int Argc,
   if (!Root.empty())
     FC = std::make_shared<FileCollector>(Root, Root);
   VFS = FileCollector::createCollectorVFS(vfs::getRealFileSystem(), FC);
 }
 
 ReproducerGenerate::~ReproducerGenerate() {
   if (GenerateOnExit && !Generated)
     generate();
+  else if (!Generated && !Root.empty())
+    sys::fs::remove_directories(Root, /* IgnoreErrors */ true);
 }
 
 void ReproducerGenerate::generate() {
   if (!FC)
     return;
   Generated = true;
   FC->copyFiles(false);
   SmallString<128> Mapping(Root);