[llvm] [Support] Report EISDIR when opening a directory (PR #79504)

[via llvm-commits]

https://github.com/azhan92 created https://github.com/llvm/llvm-project/pull/79504

The test `llvm/unittests/Support/CommandLineTest.cpp` that handles errors in expansion of response files was previously disabled for AIX. Originally the code was dependent on read returning EISDIR which occurs on platforms such as Linux. However, other platforms such as AIX follow POSIX in reporting EISDIR only if write access is requested when opening a directory as a file. This change introduces an implementation that checks the validity of the path in `llvm/lib/Support/CommandLine.cpp` instead of relying on read.



>From 205f86c29dae1187180dc4230ebe3838d9bc9fed Mon Sep 17 00:00:00 2001
From: Alison Zhang <alisonzhang at ibm.com>
Date: Thu, 25 Jan 2024 16:28:52 -0500
Subject: [PATCH] report eisdir on aix

---
 llvm/lib/Support/Unix/Path.inc                   |  7 +++++++
 .../tools/llvm-symbolizer/input-file-err.test    |  2 --
 llvm/unittests/Support/CommandLineTest.cpp       |  2 --
 llvm/unittests/Support/Path.cpp                  | 16 ++++++++++++++++
 4 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index 9f89d63bb0fda8..e6b8a0dd5e4009 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -1024,6 +1024,13 @@ std::error_code openFile(const Twine &Name, int &ResultFD,
   auto Open = [&]() { return ::open(P.begin(), OpenFlags, Mode); };
   if ((ResultFD = sys::RetryAfterSignal(-1, Open)) < 0)
     return std::error_code(errno, std::generic_category());
+  if (Access == FA_Read) {
+     struct stat Status;    
+     if (fstat(ResultFD, &Status) == -1)
+      return std::error_code(errno, std::generic_category());
+    if (S_ISDIR(Status.st_mode))
+      return make_error_code(errc::is_a_directory);
+  }
 #ifndef O_CLOEXEC
   if (!(Flags & OF_ChildInherit)) {
     int r = fcntl(ResultFD, F_SETFD, FD_CLOEXEC);
diff --git a/llvm/test/tools/llvm-symbolizer/input-file-err.test b/llvm/test/tools/llvm-symbolizer/input-file-err.test
index df14da2f433c01..76115b513470b9 100644
--- a/llvm/test/tools/llvm-symbolizer/input-file-err.test
+++ b/llvm/test/tools/llvm-symbolizer/input-file-err.test
@@ -1,5 +1,3 @@
-Failing on AIX due to D153595. The test expects a different error message from the one given on AIX.
-XFAIL: target={{.*}}-aix{{.*}}
 RUN: not llvm-addr2line -e %p/Inputs/nonexistent 0x12 2>&1 | FileCheck %s --check-prefix=CHECK-NONEXISTENT-A2L -DMSG=%errc_ENOENT
 RUN: not llvm-addr2line -e %p/Inputs/nonexistent 2>&1 | FileCheck %s --check-prefix=CHECK-NONEXISTENT-A2L -DMSG=%errc_ENOENT
 CHECK-NONEXISTENT-A2L: llvm-addr2line{{.*}}: error: '{{.*}}Inputs/nonexistent': [[MSG]]
diff --git a/llvm/unittests/Support/CommandLineTest.cpp b/llvm/unittests/Support/CommandLineTest.cpp
index bbeb9d5dc19bda..23f6081cd32a45 100644
--- a/llvm/unittests/Support/CommandLineTest.cpp
+++ b/llvm/unittests/Support/CommandLineTest.cpp
@@ -1117,7 +1117,6 @@ TEST(CommandLineTest, BadResponseFile) {
   ASSERT_STREQ(Argv[0], "clang");
   ASSERT_STREQ(Argv[1], AFileExp.c_str());
 
-#if !defined(_AIX) && !defined(__MVS__)
   std::string ADirExp = std::string("@") + std::string(ADir.path());
   Argv = {"clang", ADirExp.c_str()};
   Res = cl::ExpandResponseFiles(Saver, cl::TokenizeGNUCommandLine, Argv);
@@ -1125,7 +1124,6 @@ TEST(CommandLineTest, BadResponseFile) {
   ASSERT_EQ(2U, Argv.size());
   ASSERT_STREQ(Argv[0], "clang");
   ASSERT_STREQ(Argv[1], ADirExp.c_str());
-#endif
 }
 
 TEST(CommandLineTest, SetDefaultValue) {
diff --git a/llvm/unittests/Support/Path.cpp b/llvm/unittests/Support/Path.cpp
index 837ca03216f87a..604a8803f60e69 100644
--- a/llvm/unittests/Support/Path.cpp
+++ b/llvm/unittests/Support/Path.cpp
@@ -1296,6 +1296,22 @@ TEST_F(FileSystemTest, UTF8ToUTF16DirectoryIteration) {
 }
 #endif
 
+TEST_F(FileSystemTest, OpenDirectoryAsFile) {
+  ASSERT_NO_ERROR(fs::create_directory(Twine(TestDirectory)));
+  ASSERT_EQ(fs::create_directory(Twine(TestDirectory), false),
+            errc::file_exists);
+
+  int FD;
+  std::error_code EC;
+  EC = fs::openFileForRead(Twine(TestDirectory), FD);
+  ASSERT_EQ(EC, errc::is_a_directory);
+  EC = fs::openFileForWrite(Twine(TestDirectory), FD);
+  ASSERT_EQ(EC, errc::is_a_directory);
+
+  ASSERT_NO_ERROR(fs::remove_directories(Twine(TestDirectory)));
+  ::close(FD);
+}
+
 TEST_F(FileSystemTest, Remove) {
   SmallString<64> BaseDir;
   SmallString<64> Paths[4];