[clang] [Tooling] Print the progress when there are multiple files to process (PR #75904)

[Haojian Wu via cfe-commits]

https://github.com/hokein created https://github.com/llvm/llvm-project/pull/75904

Running clang tools on a single file can be slow. It is even worse when running multiple files, to improve the user experience, we print the processing status.

>From 35ca8fc22fd64c2e6513fa790215f72947852dd1 Mon Sep 17 00:00:00 2001
From: Haojian Wu <hokein.wu at gmail.com>
Date: Mon, 18 Dec 2023 15:40:17 +0100
Subject: [PATCH] [Tooling] Print the progress when there are multiple
 processing file.

Running clang tools on a single file can be slow. It is even worse when
running multiple files, to improve the user experience, we print the
processing status.
---
 clang/lib/Tooling/Tooling.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Tooling/Tooling.cpp b/clang/lib/Tooling/Tooling.cpp
index 33bfa8d3d81f1e..92068d04ba5460 100644
--- a/clang/lib/Tooling/Tooling.cpp
+++ b/clang/lib/Tooling/Tooling.cpp
@@ -556,6 +556,8 @@ int ClangTool::run(ToolAction *Action) {
                  << CWD.getError().message() << "\n";
   }
 
+  size_t NumOfTotalFiles = AbsolutePaths.size();
+  unsigned ProcessedFileCounter = 0;
   for (llvm::StringRef File : AbsolutePaths) {
     // Currently implementations of CompilationDatabase::getCompileCommands can
     // change the state of the file system (e.g.  prepare generated headers), so
@@ -611,7 +613,11 @@ int ClangTool::run(ToolAction *Action) {
 
       // FIXME: We need a callback mechanism for the tool writer to output a
       // customized message for each file.
-      LLVM_DEBUG({ llvm::dbgs() << "Processing: " << File << ".\n"; });
+      if (NumOfTotalFiles > 1)
+        llvm::errs() << "[" + std::to_string(++ProcessedFileCounter) + "/" +
+                            std::to_string(NumOfTotalFiles) +
+                            "] Processing file " + File
+                     << ".\n";
       ToolInvocation Invocation(std::move(CommandLine), Action, Files.get(),
                                 PCHContainerOps);
       Invocation.setDiagnosticConsumer(DiagConsumer);