[Support] Remove error return value from one overload of fs::make_absolute

Summary:
The version of make_absolute which accepted a specific directory to use
as the "base" for the computation could never fail, even though it
returned a std::error_code. The reason for that seems to be historical
-- the CWD flavour (which can fail due to failure to retrieve CWD) was
there first, and the new version was implemented by extending that.

This removes the error return value from the non-CWD overload and
reimplements the CWD version on top of that. This enables us to remove
some dead code where people were pessimistically trying to handle the
errors returned from this function.

Reviewers: zturner, sammccall

Subscribers: hiraditya, kristina, llvm-commits

Differential Revision: https://reviews.llvm.org/D56599

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351317 91177308-0d34-0410-b5e6-96231b3b80d8

Author: labath

include/llvm/Support/FileSystem.h

@@ -302,10 +302,7 @@ class file_status : public basic_file_status {
 /// relative/../path => <current-directory>/relative/../path
 ///
 /// @param path A path that is modified to be an absolute path.
-/// @returns errc::success if \a path has been made absolute, otherwise a
-///          platform-specific error_code.
-std::error_code make_absolute(const Twine &current_directory,
-                              SmallVectorImpl<char> &path);
+void make_absolute(const Twine &current_directory, SmallVectorImpl<char> &path);
 
 /// Make \a path an absolute path.
 ///

lib/Support/Path.cpp

@@ -849,9 +849,8 @@ getPotentiallyUniqueTempFileName(const Twine &Prefix, StringRef Suffix,
   return createTemporaryFile(Prefix, Suffix, Dummy, ResultPath, FS_Name);
 }
 
-static std::error_code make_absolute(const Twine &current_directory,
-                                     SmallVectorImpl<char> &path,
-                                     bool use_current_directory) {
+void make_absolute(const Twine &current_directory,
+                   SmallVectorImpl<char> &path) {
   StringRef p(path.data(), path.size());
 
   bool rootDirectory = path::has_root_directory(p);
@@ -860,22 +859,19 @@ static std::error_code make_absolute(const Twine &current_directory,
 
   // Already absolute.
   if (rootName && rootDirectory)
-    return std::error_code();
+    return;
 
   // All of the following conditions will need the current directory.
   SmallString<128> current_dir;
-  if (use_current_directory)
-    current_directory.toVector(current_dir);
-  else if (std::error_code ec = current_path(current_dir))
-    return ec;
+  current_directory.toVector(current_dir);
 
   // Relative path. Prepend the current directory.
   if (!rootName && !rootDirectory) {
     // Append path to the current directory.
     path::append(current_dir, p);
     // Set path to the result.
     path.swap(current_dir);
-    return std::error_code();
+    return;
   }
 
   if (!rootName && rootDirectory) {
@@ -884,7 +880,7 @@ static std::error_code make_absolute(const Twine &current_directory,
     path::append(curDirRootName, p);
     // Set path to the result.
     path.swap(curDirRootName);
-    return std::error_code();
+    return;
   }
 
   if (rootName && !rootDirectory) {
@@ -896,20 +892,23 @@ static std::error_code make_absolute(const Twine &current_directory,
     SmallString<128> res;
     path::append(res, pRootName, bRootDirectory, bRelativePath, pRelativePath);
     path.swap(res);
-    return std::error_code();
+    return;
   }
 
   llvm_unreachable("All rootName and rootDirectory combinations should have "
                    "occurred above!");
 }
 
-std::error_code make_absolute(const Twine &current_directory,
-                              SmallVectorImpl<char> &path) {
-  return make_absolute(current_directory, path, true);
-}
-
 std::error_code make_absolute(SmallVectorImpl<char> &path) {
-  return make_absolute(Twine(), path, false);
+  if (path::is_absolute(path))
+    return {};
+
+  SmallString<128> current_dir;
+  if (std::error_code ec = current_path(current_dir))
+    return ec;
+
+  make_absolute(current_dir, path);
+  return {};
 }
 
 std::error_code create_directories(const Twine &Path, bool IgnoreExisting,

lib/Support/VirtualFileSystem.cpp

@@ -128,7 +128,8 @@ std::error_code FileSystem::makeAbsolute(SmallVectorImpl<char> &Path) const {
   if (!WorkingDir)
     return WorkingDir.getError();
 
-  return llvm::sys::fs::make_absolute(WorkingDir.get(), Path);
+  llvm::sys::fs::make_absolute(WorkingDir.get(), Path);
+  return {};
 }
 
 std::error_code FileSystem::getRealPath(const Twine &Path,

tools/llvm-opt-report/OptReport.cpp

@@ -231,13 +231,8 @@ static bool writeReport(LocationInfoTy &LocationInfo) {
   bool FirstFile = true;
   for (auto &FI : LocationInfo) {
     SmallString<128> FileName(FI.first);
-    if (!InputRelDir.empty()) {
-      if (std::error_code EC = sys::fs::make_absolute(InputRelDir, FileName)) {
-        WithColor::error() << "Can't resolve file path to " << FileName << ": "
-                           << EC.message() << "\n";
-        return false;
-      }
-    }
+    if (!InputRelDir.empty())
+      sys::fs::make_absolute(InputRelDir, FileName);
 
     const auto &FileInfo = FI.second;
 

unittests/Support/Path.cpp

@@ -187,7 +187,7 @@ TEST(Support, Path) {
   }
 
   SmallString<32> Relative("foo.cpp");
-  ASSERT_NO_ERROR(sys::fs::make_absolute("/root", Relative));
+  sys::fs::make_absolute("/root", Relative);
   Relative[5] = '/'; // Fix up windows paths.
   ASSERT_EQ("/root/foo.cpp", Relative);
 }