[llvm] [llvm-link] Improve missing file error message (PR #82514)

[Michael Halkenhäuser via llvm-commits]

https://github.com/mhalk updated https://github.com/llvm/llvm-project/pull/82514

>From da7f21e41d1ff1a09e05a7efaeca7b7f9f109ef2 Mon Sep 17 00:00:00 2001
From: Michael Halkenhaeuser <MichaelGerald.Halkenhauser at amd.com>
Date: Wed, 21 Feb 2024 11:58:17 -0600
Subject: [PATCH] [llvm-link] Improve missing file error message

Add error messages showing the missing filenames.

Currently, we only get 'No such file or directory' without any(!) further info.
This patch will (only upon ENOENT error) iterate over all requested files and
print which ones are actually missing.
---
 llvm/tools/llvm-link/llvm-link.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/llvm/tools/llvm-link/llvm-link.cpp b/llvm/tools/llvm-link/llvm-link.cpp
index e6c219a8cd7ece..e653ae31364744 100644
--- a/llvm/tools/llvm-link/llvm-link.cpp
+++ b/llvm/tools/llvm-link/llvm-link.cpp
@@ -393,8 +393,17 @@ static bool linkFiles(const char *argv0, LLVMContext &Context, Linker &L,
   // Similar to some flags, internalization doesn't apply to the first file.
   bool InternalizeLinkedSymbols = false;
   for (const auto &File : Files) {
+    auto ErrOrExpected = MemoryBuffer::getFileOrSTDIN(File);
+
+    // When we encounter a missing file, print all missing files to stderr.
+    if (auto EC = ErrOrExpected.getError())
+      if (EC == std::errc::no_such_file_or_directory)
+        for (auto &F : Files)
+          if (!llvm::sys::fs::exists(F))
+            errs() << "No such file or directory: '" << F << "'\n";
+
     std::unique_ptr<MemoryBuffer> Buffer =
-        ExitOnErr(errorOrToExpected(MemoryBuffer::getFileOrSTDIN(File)));
+        ExitOnErr(errorOrToExpected(std::move(ErrOrExpected)));
 
     std::unique_ptr<Module> M =
         identify_magic(Buffer->getBuffer()) == file_magic::archive