Finishing touch for the std::error_code transition.

While std::error_code itself seems to work OK in all platforms, there
are few annoying differences with regards to the std::errc enumeration.

This patch adds a simple llvm enumeration, which will hopefully avoid build
breakages in other platforms and surprises as we get more uses of
std::error_code.

llvm-svn: 210920

llvm/include/llvm/Support/Errc.h

@@ -0,0 +1,86 @@
+//===- llvm/Support/Errc.h - Defines the llvm::errc enum --------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// While std::error_code works OK on all platforms we use, there are some
+// some problems with std::errc that can be avoided by using our own
+// enumeration:
+//
+// * std::errc is a namespace in some implementations. That meas that ADL
+//   doesn't work and it is sometimes necessary to write std::make_error_code
+//   or in templates:
+//   using std::make_error_code;
+//   make_error_code(...);
+//
+//   with this enum it is safe to always just use make_error_code.
+//
+// * Some implementations define fewer names than others. This header has
+//   the intersection of all the ones we support.
+//
+// * std::errc is just marked with is_error_condition_enum. This means that
+//   common patters like AnErrorCode == errc::no_such_file_or_directory take
+//   4 virtual calls instead of two comparisons.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_ERRC_H
+#define LLVM_SUPPORT_ERRC_H
+
+#include <system_error>
+
+namespace llvm {
+enum class errc {
+  argument_list_too_long = int(std::errc::argument_list_too_long),
+  argument_out_of_domain = int(std::errc::argument_out_of_domain),
+  bad_address = int(std::errc::bad_address),
+  bad_file_descriptor = int(std::errc::bad_file_descriptor),
+  broken_pipe = int(std::errc::broken_pipe),
+  device_or_resource_busy = int(std::errc::device_or_resource_busy),
+  directory_not_empty = int(std::errc::directory_not_empty),
+  executable_format_error = int(std::errc::executable_format_error),
+  file_exists = int(std::errc::file_exists),
+  file_too_large = int(std::errc::file_too_large),
+  filename_too_long = int(std::errc::filename_too_long),
+  function_not_supported = int(std::errc::function_not_supported),
+  illegal_byte_sequence = int(std::errc::illegal_byte_sequence),
+  inappropriate_io_control_operation =
+      int(std::errc::inappropriate_io_control_operation),
+  interrupted = int(std::errc::interrupted),
+  invalid_argument = int(std::errc::invalid_argument),
+  invalid_seek = int(std::errc::invalid_seek),
+  io_error = int(std::errc::io_error),
+  is_a_directory = int(std::errc::is_a_directory),
+  no_child_process = int(std::errc::no_child_process),
+  no_lock_available = int(std::errc::no_lock_available),
+  no_space_on_device = int(std::errc::no_space_on_device),
+  no_such_device_or_address = int(std::errc::no_such_device_or_address),
+  no_such_device = int(std::errc::no_such_device),
+  no_such_file_or_directory = int(std::errc::no_such_file_or_directory),
+  no_such_process = int(std::errc::no_such_process),
+  not_a_directory = int(std::errc::not_a_directory),
+  not_enough_memory = int(std::errc::not_enough_memory),
+  operation_not_permitted = int(std::errc::operation_not_permitted),
+  permission_denied = int(std::errc::permission_denied),
+  read_only_file_system = int(std::errc::read_only_file_system),
+  resource_deadlock_would_occur = int(std::errc::resource_deadlock_would_occur),
+  resource_unavailable_try_again =
+      int(std::errc::resource_unavailable_try_again),
+  result_out_of_range = int(std::errc::result_out_of_range),
+  too_many_files_open_in_system = int(std::errc::too_many_files_open_in_system),
+  too_many_files_open = int(std::errc::too_many_files_open),
+  too_many_links = int(std::errc::too_many_links)
+};
+
+inline std::error_code make_error_code(errc E) {
+  return std::error_code(static_cast<int>(E), std::generic_category());
+}
+}
+
+namespace std {
+template <> struct is_error_code_enum<llvm::errc> : std::true_type {};
+}
+#endif

llvm/include/llvm/Support/ErrorOr.h

@@ -99,7 +99,6 @@ public:
                                       std::is_error_condition_enum<E>::value,
                                   void *>::type = 0)
       : HasError(true) {
-    using std::make_error_code;
     new (getErrorStorage()) std::error_code(make_error_code(ErrorCode));
   }
 

llvm/lib/Support/FileOutputBuffer.cpp

@@ -11,6 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/FileOutputBuffer.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/raw_ostream.h"
@@ -51,7 +52,7 @@ FileOutputBuffer::create(StringRef FilePath, size_t Size,
       if (EC)
         return EC;
       else
-        return std::make_error_code(std::errc::operation_not_permitted);
+        return make_error_code(errc::operation_not_permitted);
   }
 
   // Delete target file.

llvm/lib/Support/LockFileManager.cpp

@@ -9,6 +9,7 @@
 #include "llvm/Support/LockFileManager.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
@@ -112,7 +113,7 @@ LockFileManager::LockFileManager(StringRef FileName)
     if (Out.has_error()) {
       // We failed to write out PID, so make up an excuse, remove the
       // unique lock file, and fail.
-      Error = std::make_error_code(std::errc::no_space_on_device);
+      Error = make_error_code(errc::no_space_on_device);
       sys::fs::remove(UniqueLockFileName.c_str());
       return;
     }
@@ -125,7 +126,7 @@ LockFileManager::LockFileManager(StringRef FileName)
     if (!EC)
       return;
 
-    if (EC != std::errc::file_exists) {
+    if (EC != errc::file_exists) {
       Error = EC;
       return;
     }

llvm/lib/Support/MemoryBuffer.cpp

@@ -14,6 +14,7 @@
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Config/config.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/Errno.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MathExtras.h"
@@ -364,7 +365,7 @@ static std::error_code getOpenFileImpl(int FD, const char *Filename,
   if (!Buf) {
     // Failed to create a buffer. The only way it can fail is if
     // new(std::nothrow) returns 0.
-    return std::make_error_code(std::errc::not_enough_memory);
+    return make_error_code(errc::not_enough_memory);
   }
 
   std::unique_ptr<MemoryBuffer> SB(Buf);

llvm/lib/Support/Path.cpp

@@ -11,6 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -204,7 +205,7 @@ retry_random_path:
     if (std::error_code EC =
             sys::fs::openFileForWrite(Twine(ResultPath.begin()), ResultFD,
                                       sys::fs::F_RW | sys::fs::F_Excl, Mode)) {
-      if (EC == std::errc::file_exists)
+      if (EC == errc::file_exists)
         goto retry_random_path;
       return EC;
     }
@@ -225,7 +226,7 @@ retry_random_path:
   case FS_Dir: {
     if (std::error_code EC =
             sys::fs::create_directory(ResultPath.begin(), false)) {
-      if (EC == std::errc::file_exists)
+      if (EC == errc::file_exists)
         goto retry_random_path;
       return EC;
     }
@@ -830,7 +831,7 @@ std::error_code create_directories(const Twine &Path, bool IgnoreExisting) {
   std::error_code EC = create_directory(P, IgnoreExisting);
   // If we succeeded, or had any error other than the parent not existing, just
   // return it.
-  if (EC != std::errc::no_such_file_or_directory)
+  if (EC != errc::no_such_file_or_directory)
     return EC;
 
   // We failed because of a no_such_file_or_directory, try to create the

llvm/lib/Support/Unix/Path.inc

@@ -317,7 +317,7 @@ std::error_code remove(const Twine &path, bool IgnoreNonExisting) {
   // effectively prevents LLVM from erasing things like /dev/null, any block
   // special file, or other things that aren't "regular" files.
   if (!S_ISREG(buf.st_mode) && !S_ISDIR(buf.st_mode) && !S_ISLNK(buf.st_mode))
-    return make_error_code(std::errc::operation_not_permitted);
+    return make_error_code(errc::operation_not_permitted);
 
   if (::remove(p.begin()) == -1) {
     if (errno != ENOENT || !IgnoreNonExisting)
@@ -404,7 +404,7 @@ static std::error_code fillStatus(int StatRet, const struct stat &Status,
                              file_status &Result) {
   if (StatRet != 0) {
     std::error_code ec(errno, std::generic_category());
-    if (ec == std::errc::no_such_file_or_directory)
+    if (ec == errc::no_such_file_or_directory)
       Result = file_status(file_type::file_not_found);
     else
       Result = file_status(file_type::status_error);
@@ -468,7 +468,7 @@ std::error_code setLastModificationAndAccessTime(int FD, TimeValue Time) {
   return std::error_code();
 #else
 #warning Missing futimes() and futimens()
-  return make_error_code(std::errc::not_supported);
+  return make_error_code(errc::not_supported);
 #endif
 }
 
@@ -512,7 +512,7 @@ mapped_file_region::mapped_file_region(const Twine &path,
   , Mapping() {
   // Make sure that the requested size fits within SIZE_T.
   if (length > std::numeric_limits<size_t>::max()) {
-    ec = make_error_code(std::errc::invalid_argument);
+    ec = make_error_code(errc::invalid_argument);
     return;
   }
 
@@ -541,7 +541,7 @@ mapped_file_region::mapped_file_region(int fd,
   , Mapping() {
   // Make sure that the requested size fits within SIZE_T.
   if (length > std::numeric_limits<size_t>::max()) {
-    ec = make_error_code(std::errc::invalid_argument);
+    ec = make_error_code(errc::invalid_argument);
     return;
   }
 

llvm/lib/Support/Windows/Path.inc

@@ -196,7 +196,7 @@ std::error_code remove(const Twine &path, bool IgnoreNonExisting) {
 
   file_status ST;
   if (std::error_code EC = status(path, ST)) {
-    if (EC != std::errc::no_such_file_or_directory || !IgnoreNonExisting)
+    if (EC != errc::no_such_file_or_directory || !IgnoreNonExisting)
       return EC;
     return std::error_code();
   }
@@ -208,14 +208,14 @@ std::error_code remove(const Twine &path, bool IgnoreNonExisting) {
   if (ST.type() == file_type::directory_file) {
     if (!::RemoveDirectoryW(c_str(path_utf16))) {
       std::error_code EC = windows_error(::GetLastError());
-      if (EC != std::errc::no_such_file_or_directory || !IgnoreNonExisting)
+      if (EC != errc::no_such_file_or_directory || !IgnoreNonExisting)
         return EC;
     }
     return std::error_code();
   }
   if (!::DeleteFileW(c_str(path_utf16))) {
     std::error_code EC = windows_error(::GetLastError());
-    if (EC != std::errc::no_such_file_or_directory || !IgnoreNonExisting)
+    if (EC != errc::no_such_file_or_directory || !IgnoreNonExisting)
       return EC;
   }
   return std::error_code();
@@ -481,7 +481,7 @@ std::error_code mapped_file_region::init(int FD, bool CloseFD, uint64_t Offset)
         _close(FileDescriptor);
     } else
       ::CloseHandle(FileHandle);
-    return std::make_error_code(std::errc::invalid_argument);
+    return make_error_code(errc::invalid_argument);
   }
 
   DWORD flprotect;
@@ -617,7 +617,7 @@ mapped_file_region::mapped_file_region(int fd,
     if (closefd)
       _close(FileDescriptor);
     FileDescriptor = 0;
-    ec = std::make_error_code(std::errc::bad_file_descriptor);
+    ec = make_error_code(errc::bad_file_descriptor);
     return;
   }
 
@@ -779,7 +779,7 @@ std::error_code openFileForRead(const Twine &Name, int &ResultFD) {
     if (LastError != ERROR_ACCESS_DENIED)
       return EC;
     if (is_directory(Name))
-      return std::make_error_code(std::errc::is_a_directory);
+      return make_error_code(errc::is_a_directory);
     return EC;
   }
 
@@ -831,7 +831,7 @@ std::error_code openFileForWrite(const Twine &Name, int &ResultFD,
     if (LastError != ERROR_ACCESS_DENIED)
       return EC;
     if (is_directory(Name))
-      return std::make_error_code(std::errc::is_a_directory);
+      return make_error_code(errc::is_a_directory);
     return EC;
   }
 

llvm/lib/Support/WindowsError.cpp

@@ -12,12 +12,12 @@
 //  errors to generic ones. The one implemented in msvc is too conservative
 //  for llvm, so we do an extra mapping when constructing an error_code
 //  from an windows error. This allows the rest of llvm to simple checks
-//  like "EC == std::errc::file_exists" and have it work on both posix and
+//  like "EC == errc::file_exists" and have it work on both posix and
 //  windows.
 //
 //===----------------------------------------------------------------------===//
 
-
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/WindowsError.h"
 
 #include "llvm/Config/llvm-config.h"
@@ -30,7 +30,7 @@
 // I'd rather not double the line count of the following.
 #define MAP_ERR_TO_COND(x, y)                                                  \
   case x:                                                                      \
-    return std::make_error_code(std::errc::y)
+    return make_error_code(errc::y)
 
 std::error_code llvm::mapWindowsError(unsigned EV) {
   switch (EV) {

llvm/lib/Support/YAMLTraits.cpp

@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/YAMLTraits.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/Casting.h"
@@ -72,7 +73,7 @@ bool Input::setCurrentDocument() {
     Node *N = DocIterator->getRoot();
     if (!N) {
       assert(Strm->failed() && "Root is NULL iff parsing failed");
-      EC = std::make_error_code(std::errc::invalid_argument);
+      EC = make_error_code(errc::invalid_argument);
       return false;
     }
 
@@ -122,7 +123,7 @@ bool Input::preflightKey(const char *Key, bool Required, bool, bool &UseDefault,
   // nodes are present.
   if (!CurrentNode) {
     if (Required)
-      EC = std::make_error_code(std::errc::invalid_argument);
+      EC = make_error_code(errc::invalid_argument);
     return false;
   }
 
@@ -298,7 +299,7 @@ void Input::setError(HNode *hnode, const Twine &message) {
 
 void Input::setError(Node *node, const Twine &message) {
   Strm->printError(node, message);
-  EC = std::make_error_code(std::errc::invalid_argument);
+  EC = make_error_code(errc::invalid_argument);
 }
 
 Input::HNode *Input::createHNodes(Node *N) {

llvm/tools/llvm-ar/llvm-ar.cpp

@@ -17,6 +17,7 @@
 #include "llvm/Object/Archive.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/ManagedStatic.h"
@@ -453,7 +454,7 @@ int NewArchiveIterator::getFD() const {
   // Linux cannot open directories with open(2), although
   // cygwin and *bsd can.
   if (NewStatus.type() == sys::fs::file_type::directory_file)
-    failIfError(std::make_error_code(std::errc::is_a_directory), NewFilename);
+    failIfError(make_error_code(errc::is_a_directory), NewFilename);
 
   return NewFD;
 }
@@ -939,7 +940,7 @@ static int performOperation(ArchiveOperation Operation) {
   // Create or open the archive object.
   std::unique_ptr<MemoryBuffer> Buf;
   std::error_code EC = MemoryBuffer::getFile(ArchiveName, Buf, -1, false);
-  if (EC && EC != std::errc::no_such_file_or_directory) {
+  if (EC && EC != errc::no_such_file_or_directory) {
     errs() << ToolName << ": error opening '" << ArchiveName
            << "': " << EC.message() << "!\n";
     return 1;
@@ -957,7 +958,7 @@ static int performOperation(ArchiveOperation Operation) {
     return 0;
   }
 
-  assert(EC == std::errc::no_such_file_or_directory);
+  assert(EC == errc::no_such_file_or_directory);
 
   if (!shouldCreateArchive(Operation)) {
     failIfError(EC, Twine("error loading '") + ArchiveName + "'");

llvm/tools/llvm-cov/llvm-cov.cpp

@@ -13,6 +13,7 @@
 
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/GCOV.h"
 #include "llvm/Support/ManagedStatic.h"
@@ -116,7 +117,7 @@ int main(int argc, char **argv) {
 
   std::unique_ptr<MemoryBuffer> GCDA_Buff;
   if (std::error_code ec = MemoryBuffer::getFileOrSTDIN(InputGCDA, GCDA_Buff)) {
-    if (ec != std::errc::no_such_file_or_directory) {
+    if (ec != errc::no_such_file_or_directory) {
       errs() << InputGCDA << ": " << ec.message() << "\n";
       return 1;
     }

llvm/tools/llvm-symbolizer/LLVMSymbolize.cpp

@@ -19,6 +19,7 @@
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Compression.h"
 #include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
@@ -311,7 +312,7 @@ LLVMSymbolizer::getOrCreateBinary(const std::string &Path) {
           getDarwinDWARFResourceForPath(Path);
       BinaryOrErr = createBinary(ResourcePath);
       std::error_code EC = BinaryOrErr.getError();
-      if (EC != std::errc::no_such_file_or_directory && !error(EC)) {
+      if (EC != errc::no_such_file_or_directory && !error(EC)) {
         DbgBin = BinaryOrErr.get();
         ParsedBinariesAndObjects.push_back(std::unique_ptr<Binary>(DbgBin));
       }

llvm/unittests/Support/ErrorOrTest.cpp

@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/ErrorOr.h"
+#include "llvm/Support/Errc.h"
 #include "gtest/gtest.h"
 #include <memory>
 
@@ -16,7 +17,7 @@ using namespace llvm;
 namespace {
 
 ErrorOr<int> t1() {return 1;}
-ErrorOr<int> t2() { return std::errc::invalid_argument; }
+ErrorOr<int> t2() { return errc::invalid_argument; }
 
 TEST(ErrorOr, SimpleValue) {
   ErrorOr<int> a = t1();
@@ -30,7 +31,7 @@ TEST(ErrorOr, SimpleValue) {
 
   a = t2();
   EXPECT_FALSE(a);
-  EXPECT_EQ(std::errc::invalid_argument, a.getError());
+  EXPECT_EQ(a.getError(), errc::invalid_argument);
 #ifdef EXPECT_DEBUG_DEATH
   EXPECT_DEBUG_DEATH(*a, "Cannot get value when an error exists");
 #endif

llvm/unittests/Support/Path.cpp

@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/Path.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -355,10 +356,10 @@ TEST_F(FileSystemTest, TempFiles) {
   ASSERT_NO_ERROR(fs::remove(Twine(TempPath2)));
   ASSERT_NO_ERROR(fs::remove(Twine(TempPath2)));
   ASSERT_EQ(fs::remove(Twine(TempPath2), false),
-            std::errc::no_such_file_or_directory);
+            errc::no_such_file_or_directory);
 
   std::error_code EC = fs::status(TempPath2.c_str(), B);
-  EXPECT_EQ(EC, std::errc::no_such_file_or_directory);
+  EXPECT_EQ(EC, errc::no_such_file_or_directory);
   EXPECT_EQ(B.type(), fs::file_type::file_not_found);
 
   // Make sure Temp2 doesn't exist.
@@ -398,7 +399,7 @@ TEST_F(FileSystemTest, TempFiles) {
     "abcdefghijklmnopqrstuvwxyz3abcdefghijklmnopqrstuvwxyz2"
     "abcdefghijklmnopqrstuvwxyz1abcdefghijklmnopqrstuvwxyz0";
   EXPECT_EQ(fs::createUniqueFile(Twine(Path270), FileDescriptor, TempPath),
-            std::errc::no_such_file_or_directory);
+            errc::no_such_file_or_directory);
 #endif
 }
 
@@ -406,7 +407,7 @@ TEST_F(FileSystemTest, CreateDir) {
   ASSERT_NO_ERROR(fs::create_directory(Twine(TestDirectory) + "foo"));
   ASSERT_NO_ERROR(fs::create_directory(Twine(TestDirectory) + "foo"));
   ASSERT_EQ(fs::create_directory(Twine(TestDirectory) + "foo", false),
-            std::errc::file_exists);
+            errc::file_exists);
   ASSERT_NO_ERROR(fs::remove(Twine(TestDirectory) + "foo"));
 }
 

llvm/unittests/Transforms/DebugIR/DebugIR.cpp

@@ -18,6 +18,7 @@
 #include "llvm/IR/DIBuilder.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Support/Errc.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/Path.h"
@@ -58,7 +59,7 @@ bool removeIfExists(StringRef Path) {
   // This is an approximation, on error we don't know in general if the file
   // existed or not.
   std::error_code EC = sys::fs::remove(Path, false);
-  return EC != std::errc::no_such_file_or_directory;
+  return EC != llvm::errc::no_such_file_or_directory;
 }
 
 char * current_dir() {