diff --git a/tools/bugpoint/ExecutionDriver.cpp b/tools/bugpoint/ExecutionDriver.cpp
index b41a4b03346..25813b34e62 100644
--- a/tools/bugpoint/ExecutionDriver.cpp
+++ b/tools/bugpoint/ExecutionDriver.cpp
@@ -22,7 +22,6 @@
 #include <fstream>
 
 using namespace llvm;
-using std::error_code;
 
 namespace {
   // OutputType - Allow the user to specify the way code should be run, to test
@@ -268,7 +267,7 @@ void BugDriver::compileProgram(Module *M, std::string *Error) const {
   // Emit the program to a bitcode file...
   SmallString<128> BitcodeFile;
   int BitcodeFD;
-  error_code EC = sys::fs::createUniqueFile(
+  std::error_code EC = sys::fs::createUniqueFile(
       OutputPrefix + "-test-program-%%%%%%%.bc", BitcodeFD, BitcodeFile);
   if (EC) {
     errs() << ToolName << ": Error making unique filename: " << EC.message()
@@ -306,7 +305,7 @@ std::string BugDriver::executeProgram(const Module *Program,
     // Emit the program to a bitcode file...
     SmallString<128> UniqueFilename;
     int UniqueFD;
-    error_code EC = sys::fs::createUniqueFile(
+    std::error_code EC = sys::fs::createUniqueFile(
         OutputPrefix + "-test-program-%%%%%%%.bc", UniqueFD, UniqueFilename);
     if (EC) {
       errs() << ToolName << ": Error making unique filename: "
@@ -332,7 +331,7 @@ std::string BugDriver::executeProgram(const Module *Program,
 
   // Check to see if this is a valid output filename...
   SmallString<128> UniqueFile;
-  error_code EC = sys::fs::createUniqueFile(OutputFile, UniqueFile);
+  std::error_code EC = sys::fs::createUniqueFile(OutputFile, UniqueFile);
   if (EC) {
     errs() << ToolName << ": Error making unique filename: "
            << EC.message() << "\n";
diff --git a/tools/bugpoint/ExtractFunction.cpp b/tools/bugpoint/ExtractFunction.cpp
index a257840b6e0..4fb68566ac6 100644
--- a/tools/bugpoint/ExtractFunction.cpp
+++ b/tools/bugpoint/ExtractFunction.cpp
@@ -33,7 +33,6 @@
 #include "llvm/Transforms/Utils/CodeExtractor.h"
 #include <set>
 using namespace llvm;
-using std::error_code;
 
 #define DEBUG_TYPE "bugpoint"
 
@@ -367,7 +366,7 @@ Module *BugDriver::ExtractMappedBlocksFromModule(const
                                                  Module *M) {
   SmallString<128> Filename;
   int FD;
-  error_code EC = sys::fs::createUniqueFile(
+  std::error_code EC = sys::fs::createUniqueFile(
       OutputPrefix + "-extractblocks%%%%%%%", FD, Filename);
   if (EC) {
     outs() << "*** Basic Block extraction failed!\n";
diff --git a/tools/bugpoint/Miscompilation.cpp b/tools/bugpoint/Miscompilation.cpp
index 5143fa1f037..3f1f84ef624 100644
--- a/tools/bugpoint/Miscompilation.cpp
+++ b/tools/bugpoint/Miscompilation.cpp
@@ -27,7 +27,6 @@
 #include "llvm/Support/FileUtilities.h"
 #include "llvm/Transforms/Utils/Cloning.h"
 using namespace llvm;
-using std::error_code;
 
 namespace llvm {
   extern cl::opt<std::string> OutputPrefix;
@@ -965,8 +964,8 @@ static bool TestCodeGenerator(BugDriver &BD, Module *Test, Module *Safe,
 
   SmallString<128> TestModuleBC;
   int TestModuleFD;
-  error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc",
-                                               TestModuleFD, TestModuleBC);
+  std::error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc",
+                                                    TestModuleFD, TestModuleBC);
   if (EC) {
     errs() << BD.getToolName() << "Error making unique filename: "
            << EC.message() << "\n";
@@ -1059,8 +1058,8 @@ bool BugDriver::debugCodeGenerator(std::string *Error) {
 
   SmallString<128> TestModuleBC;
   int TestModuleFD;
-  error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc",
-                                               TestModuleFD, TestModuleBC);
+  std::error_code EC = sys::fs::createTemporaryFile("bugpoint.test", "bc",
+                                                    TestModuleFD, TestModuleBC);
   if (EC) {
     errs() << getToolName() << "Error making unique filename: "
            << EC.message() << "\n";
diff --git a/tools/bugpoint/OptimizerDriver.cpp b/tools/bugpoint/OptimizerDriver.cpp
index 85790b0c631..d452fd94c06 100644
--- a/tools/bugpoint/OptimizerDriver.cpp
+++ b/tools/bugpoint/OptimizerDriver.cpp
@@ -35,7 +35,6 @@
 #include <fstream>
 
 using namespace llvm;
-using std::error_code;
 
 #define DEBUG_TYPE "bugpoint"
 
@@ -130,7 +129,7 @@ bool BugDriver::runPasses(Module *Program,
   // setup the output file name
   outs().flush();
   SmallString<128> UniqueFilename;
-  error_code EC = sys::fs::createUniqueFile(
+  std::error_code EC = sys::fs::createUniqueFile(
       OutputPrefix + "-output-%%%%%%%.bc", UniqueFilename);
   if (EC) {
     errs() << getToolName() << ": Error making unique filename: "
diff --git a/tools/bugpoint/ToolRunner.cpp b/tools/bugpoint/ToolRunner.cpp
index ec120bb0b2f..4a2401b530f 100644
--- a/tools/bugpoint/ToolRunner.cpp
+++ b/tools/bugpoint/ToolRunner.cpp
@@ -22,7 +22,6 @@
 #include <fstream>
 #include <sstream>
 using namespace llvm;
-using std::error_code;
 
 #define DEBUG_TYPE "toolrunner"
 
@@ -143,7 +142,7 @@ static std::string ProcessFailure(StringRef ProgPath, const char** Args,
   // Rerun the compiler, capturing any error messages to print them.
   SmallString<128> ErrorFilename;
   int ErrorFD;
-  error_code EC = sys::fs::createTemporaryFile(
+  std::error_code EC = sys::fs::createTemporaryFile(
       "bugpoint.program_error_messages", "", ErrorFD, ErrorFilename);
   if (EC) {
     errs() << "Error making unique filename: " << EC.message() << "\n";
@@ -479,7 +478,7 @@ GCC::FileType LLC::OutputCode(const std::string &Bitcode,
   const char *Suffix = (UseIntegratedAssembler ? ".llc.o" : ".llc.s");
 
   SmallString<128> UniqueFile;
-  error_code EC =
+  std::error_code EC =
       sys::fs::createUniqueFile(Bitcode + "-%%%%%%%" + Suffix, UniqueFile);
   if (EC) {
     errs() << "Error making unique filename: " << EC.message() << "\n";
@@ -716,7 +715,7 @@ int GCC::ExecuteProgram(const std::string &ProgramFile,
   GCCArgs.push_back("-o");
 
   SmallString<128> OutputBinary;
-  error_code EC =
+  std::error_code EC =
       sys::fs::createUniqueFile(ProgramFile + "-%%%%%%%.gcc.exe", OutputBinary);
   if (EC) {
     errs() << "Error making unique filename: " << EC.message() << "\n";
@@ -826,7 +825,7 @@ int GCC::MakeSharedObject(const std::string &InputFile, FileType fileType,
                           const std::vector<std::string> &ArgsForGCC,
                           std::string &Error) {
   SmallString<128> UniqueFilename;
-  error_code EC = sys::fs::createUniqueFile(
+  std::error_code EC = sys::fs::createUniqueFile(
       InputFile + "-%%%%%%%" + LTDL_SHLIB_EXT, UniqueFilename);
   if (EC) {
     errs() << "Error making unique filename: " << EC.message() << "\n";
diff --git a/tools/gold/gold-plugin.cpp b/tools/gold/gold-plugin.cpp
index 2030fbd6c83..371574f2615 100644
--- a/tools/gold/gold-plugin.cpp
+++ b/tools/gold/gold-plugin.cpp
@@ -44,7 +44,6 @@
 #endif
 
 using namespace llvm;
-using std::error_code;
 
 namespace {
   ld_plugin_status discard_message(int level, const char *format, ...) {
@@ -259,7 +258,7 @@ static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
     if (file->offset) {
       offset = file->offset;
     }
-    if (error_code ec = MemoryBuffer::getOpenFileSlice(
+    if (std::error_code ec = MemoryBuffer::getOpenFileSlice(
             file->fd, file->name, buffer, file->filesize, offset)) {
       (*message)(LDPL_ERROR, ec.message().c_str());
       return LDPS_ERR;
@@ -485,7 +484,7 @@ static ld_plugin_status all_symbols_read_hook(void) {
 
 static ld_plugin_status cleanup_hook(void) {
   for (int i = 0, e = Cleanup.size(); i != e; ++i) {
-    error_code EC = sys::fs::remove(Cleanup[i]);
+    std::error_code EC = sys::fs::remove(Cleanup[i]);
     if (EC)
       (*message)(LDPL_ERROR, "Failed to delete '%s': %s", Cleanup[i].c_str(),
                  EC.message().c_str());
diff --git a/tools/lli/RemoteMemoryManager.cpp b/tools/lli/RemoteMemoryManager.cpp
index 041f7c7afd0..481651772af 100644
--- a/tools/lli/RemoteMemoryManager.cpp
+++ b/tools/lli/RemoteMemoryManager.cpp
@@ -19,7 +19,6 @@
 #include "llvm/Support/Format.h"
 
 using namespace llvm;
-using std::error_code;
 
 #define DEBUG_TYPE "lli"
 
@@ -62,7 +61,7 @@ allocateDataSection(uintptr_t Size, unsigned Alignment,
 }
 
 sys::MemoryBlock RemoteMemoryManager::allocateSection(uintptr_t Size) {
-  error_code ec;
+  std::error_code ec;
   sys::MemoryBlock MB = sys::Memory::allocateMappedMemory(Size,
                                                           &Near,
                                                           sys::Memory::MF_READ |
diff --git a/tools/lli/lli.cpp b/tools/lli/lli.cpp
index 2c8a4749fdb..73a19ac6679 100644
--- a/tools/lli/lli.cpp
+++ b/tools/lli/lli.cpp
@@ -62,7 +62,6 @@
 #endif
 
 using namespace llvm;
-using std::error_code;
 
 #define DEBUG_TYPE "lli"
 
@@ -416,7 +415,7 @@ int main(int argc, char **argv, char * const *envp) {
 
   // If not jitting lazily, load the whole bitcode file eagerly too.
   if (NoLazyCompilation) {
-    if (error_code EC = Mod->materializeAllPermanently()) {
+    if (std::error_code EC = Mod->materializeAllPermanently()) {
       errs() << argv[0] << ": bitcode didn't read correctly.\n";
       errs() << "Reason: " << EC.message() << "\n";
       exit(1);
@@ -540,7 +539,7 @@ int main(int argc, char **argv, char * const *envp) {
 
   for (unsigned i = 0, e = ExtraArchives.size(); i != e; ++i) {
     std::unique_ptr<MemoryBuffer> ArBuf;
-    error_code ec;
+    std::error_code ec;
     ec = MemoryBuffer::getFileOrSTDIN(ExtraArchives[i], ArBuf);
     if (ec) {
       Err.print(argv[0], errs());
diff --git a/tools/llvm-ar/llvm-ar.cpp b/tools/llvm-ar/llvm-ar.cpp
index d0d4f1477da..227adb44215 100644
--- a/tools/llvm-ar/llvm-ar.cpp
+++ b/tools/llvm-ar/llvm-ar.cpp
@@ -36,7 +36,6 @@
 #endif
 
 using namespace llvm;
-using std::error_code;
 
 // The name this program was invoked as.
 static StringRef ToolName;
@@ -54,7 +53,7 @@ LLVM_ATTRIBUTE_NORETURN static void fail(Twine Error) {
   exit(1);
 }
 
-static void failIfError(error_code EC, Twine Context = "") {
+static void failIfError(std::error_code EC, Twine Context = "") {
   if (!EC)
     return;
 
@@ -939,7 +938,7 @@ int ar_main(char **argv) {
 static int performOperation(ArchiveOperation Operation) {
   // Create or open the archive object.
   std::unique_ptr<MemoryBuffer> Buf;
-  error_code EC = MemoryBuffer::getFile(ArchiveName, Buf, -1, false);
+  std::error_code EC = MemoryBuffer::getFile(ArchiveName, Buf, -1, false);
   if (EC && EC != std::errc::no_such_file_or_directory) {
     errs() << ToolName << ": error opening '" << ArchiveName
            << "': " << EC.message() << "!\n";
diff --git a/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp b/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
index d29c83714ab..fe2b235e53c 100644
--- a/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
+++ b/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
@@ -43,7 +43,6 @@
 #include <map>
 #include <system_error>
 using namespace llvm;
-using std::error_code;
 
 static cl::opt<std::string>
   InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
@@ -481,8 +480,7 @@ static int AnalyzeBitcode() {
   // Read the input file.
   std::unique_ptr<MemoryBuffer> MemBuf;
 
-  if (error_code ec =
-        MemoryBuffer::getFileOrSTDIN(InputFilename, MemBuf))
+  if (std::error_code ec = MemoryBuffer::getFileOrSTDIN(InputFilename, MemBuf))
     return Error("Error reading '" + InputFilename + "': " + ec.message());
 
   if (MemBuf->getBufferSize() & 3)
diff --git a/tools/llvm-cov/llvm-cov.cpp b/tools/llvm-cov/llvm-cov.cpp
index 97a91dd544a..b233a90bf58 100644
--- a/tools/llvm-cov/llvm-cov.cpp
+++ b/tools/llvm-cov/llvm-cov.cpp
@@ -22,7 +22,6 @@
 #include "llvm/Support/Signals.h"
 #include <system_error>
 using namespace llvm;
-using std::error_code;
 
 static cl::opt<std::string> SourceFile(cl::Positional, cl::Required,
                                        cl::desc("SOURCEFILE"));
@@ -105,7 +104,7 @@ int main(int argc, char **argv) {
   GCOVFile GF;
 
   std::unique_ptr<MemoryBuffer> GCNO_Buff;
-  if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputGCNO, GCNO_Buff)) {
+  if (std::error_code ec = MemoryBuffer::getFileOrSTDIN(InputGCNO, GCNO_Buff)) {
     errs() << InputGCNO << ": " << ec.message() << "\n";
     return 1;
   }
@@ -116,7 +115,7 @@ int main(int argc, char **argv) {
   }
 
   std::unique_ptr<MemoryBuffer> GCDA_Buff;
-  if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputGCDA, GCDA_Buff)) {
+  if (std::error_code ec = MemoryBuffer::getFileOrSTDIN(InputGCDA, GCDA_Buff)) {
     if (ec != std::errc::no_such_file_or_directory) {
       errs() << InputGCDA << ": " << ec.message() << "\n";
       return 1;
diff --git a/tools/llvm-dis/llvm-dis.cpp b/tools/llvm-dis/llvm-dis.cpp
index f5dfedbc477..3b0f838f1d7 100644
--- a/tools/llvm-dis/llvm-dis.cpp
+++ b/tools/llvm-dis/llvm-dis.cpp
@@ -34,7 +34,6 @@
 #include "llvm/Support/ToolOutputFile.h"
 #include <system_error>
 using namespace llvm;
-using std::error_code;
 
 static cl::opt<std::string>
 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
@@ -138,7 +137,7 @@ int main(int argc, char **argv) {
     M.reset(getStreamedBitcodeModule(DisplayFilename, streamer, Context,
                                      &ErrorMessage));
     if(M.get()) {
-      if (error_code EC = M->materializeAllPermanently()) {
+      if (std::error_code EC = M->materializeAllPermanently()) {
         ErrorMessage = EC.message();
         M.reset();
       }
diff --git a/tools/llvm-dwarfdump/llvm-dwarfdump.cpp b/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
index 2f10f2994fa..29f0c8707a5 100644
--- a/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
+++ b/tools/llvm-dwarfdump/llvm-dwarfdump.cpp
@@ -33,7 +33,6 @@
 
 using namespace llvm;
 using namespace object;
-using std::error_code;
 
 static cl::list<std::string>
 InputFilenames(cl::Positional, cl::desc("<input object files>"),
@@ -69,13 +68,13 @@ DumpType("debug-dump", cl::init(DIDT_All),
 static void DumpInput(const StringRef &Filename) {
   std::unique_ptr<MemoryBuffer> Buff;
 
-  if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, Buff)) {
+  if (std::error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, Buff)) {
     errs() << Filename << ": " << ec.message() << "\n";
     return;
   }
 
   ErrorOr<ObjectFile*> ObjOrErr(ObjectFile::createObjectFile(Buff.release()));
-  if (error_code EC = ObjOrErr.getError()) {
+  if (std::error_code EC = ObjOrErr.getError()) {
     errs() << Filename << ": " << EC.message() << '\n';
     return;
   }
diff --git a/tools/llvm-mc/llvm-mc.cpp b/tools/llvm-mc/llvm-mc.cpp
index 24a2d6f208e..a6b74a7b1ba 100644
--- a/tools/llvm-mc/llvm-mc.cpp
+++ b/tools/llvm-mc/llvm-mc.cpp
@@ -40,7 +40,6 @@
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/ToolOutputFile.h"
 using namespace llvm;
-using std::error_code;
 
 static cl::opt<std::string>
 InputFilename(cl::Positional, cl::desc("<input file>"), cl::init("-"));
@@ -368,7 +367,8 @@ int main(int argc, char **argv) {
     return 1;
 
   std::unique_ptr<MemoryBuffer> BufferPtr;
-  if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputFilename, BufferPtr)) {
+  if (std::error_code ec =
+          MemoryBuffer::getFileOrSTDIN(InputFilename, BufferPtr)) {
     errs() << ProgName << ": " << ec.message() << '\n';
     return 1;
   }
diff --git a/tools/llvm-mcmarkup/llvm-mcmarkup.cpp b/tools/llvm-mcmarkup/llvm-mcmarkup.cpp
index e8416d60126..cbb0d51dd3d 100644
--- a/tools/llvm-mcmarkup/llvm-mcmarkup.cpp
+++ b/tools/llvm-mcmarkup/llvm-mcmarkup.cpp
@@ -21,7 +21,6 @@
 #include "llvm/Support/raw_ostream.h"
 #include <system_error>
 using namespace llvm;
-using std::error_code;
 
 static cl::list<std::string>
        InputFilenames(cl::Positional, cl::desc("<input files>"),
@@ -137,7 +136,7 @@ MarkupTag MarkupParser::parseTag() {
 
 static void parseMCMarkup(StringRef Filename) {
   std::unique_ptr<MemoryBuffer> BufferPtr;
-  if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, BufferPtr)) {
+  if (std::error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, BufferPtr)) {
     errs() << ToolName << ": " << ec.message() << '\n';
     return;
   }
diff --git a/tools/llvm-nm/llvm-nm.cpp b/tools/llvm-nm/llvm-nm.cpp
index 6476a60c7e1..19d9888e8a6 100644
--- a/tools/llvm-nm/llvm-nm.cpp
+++ b/tools/llvm-nm/llvm-nm.cpp
@@ -45,7 +45,6 @@
 #include <vector>
 using namespace llvm;
 using namespace object;
-using std::error_code;
 
 namespace {
 enum OutputFormatTy { bsd, sysv, posix, darwin };
@@ -133,7 +132,7 @@ static void error(Twine Message, Twine Path = Twine()) {
   errs() << ToolName << ": " << Path << ": " << Message << ".\n";
 }
 
-static bool error(error_code EC, Twine Path = Twine()) {
+static bool error(std::error_code EC, Twine Path = Twine()) {
   if (EC) {
     error(EC.message(), Path);
     return true;
diff --git a/tools/llvm-objdump/COFFDump.cpp b/tools/llvm-objdump/COFFDump.cpp
index 84799ec8b00..39d8e8e39f8 100644
--- a/tools/llvm-objdump/COFFDump.cpp
+++ b/tools/llvm-objdump/COFFDump.cpp
@@ -29,7 +29,6 @@
 using namespace llvm;
 using namespace object;
 using namespace llvm::Win64EH;
-using std::error_code;
 
 // Returns the name of the unwind code.
 static StringRef getUnwindCodeTypeName(uint8_t Code) {
@@ -158,14 +157,14 @@ static void printAllUnwindCodes(ArrayRef<UnwindCode> UCs) {
 }
 
 // Given a symbol sym this functions returns the address and section of it.
-static error_code resolveSectionAndAddress(const COFFObjectFile *Obj,
-                                           const SymbolRef &Sym,
-                                           const coff_section *&ResolvedSection,
-                                           uint64_t &ResolvedAddr) {
-  if (error_code EC = Sym.getAddress(ResolvedAddr))
+static std::error_code
+resolveSectionAndAddress(const COFFObjectFile *Obj, const SymbolRef &Sym,
+                         const coff_section *&ResolvedSection,
+                         uint64_t &ResolvedAddr) {
+  if (std::error_code EC = Sym.getAddress(ResolvedAddr))
     return EC;
   section_iterator iter(Obj->section_begin());
-  if (error_code EC = Sym.getSection(iter))
+  if (std::error_code EC = Sym.getSection(iter))
     return EC;
   ResolvedSection = Obj->getCOFFSection(*iter);
   return object_error::success;
@@ -173,13 +172,13 @@ static error_code resolveSectionAndAddress(const COFFObjectFile *Obj,
 
 // Given a vector of relocations for a section and an offset into this section
 // the function returns the symbol used for the relocation at the offset.
-static error_code resolveSymbol(const std::vector<RelocationRef> &Rels,
-                                uint64_t Offset, SymbolRef &Sym) {
+static std::error_code resolveSymbol(const std::vector<RelocationRef> &Rels,
+                                     uint64_t Offset, SymbolRef &Sym) {
   for (std::vector<RelocationRef>::const_iterator I = Rels.begin(),
                                                   E = Rels.end();
                                                   I != E; ++I) {
     uint64_t Ofs;
-    if (error_code EC = I->getOffset(Ofs))
+    if (std::error_code EC = I->getOffset(Ofs))
       return EC;
     if (Ofs == Offset) {
       Sym = *I->getSymbol();
@@ -193,18 +192,17 @@ static error_code resolveSymbol(const std::vector<RelocationRef> &Rels,
 // the function resolves the symbol used for the relocation at the offset and
 // returns the section content and the address inside the content pointed to
 // by the symbol.
-static error_code getSectionContents(const COFFObjectFile *Obj,
-                                     const std::vector<RelocationRef> &Rels,
-                                     uint64_t Offset,
-                                     ArrayRef<uint8_t> &Contents,
-                                     uint64_t &Addr) {
+static std::error_code
+getSectionContents(const COFFObjectFile *Obj,
+                   const std::vector<RelocationRef> &Rels, uint64_t Offset,
+                   ArrayRef<uint8_t> &Contents, uint64_t &Addr) {
   SymbolRef Sym;
-  if (error_code EC = resolveSymbol(Rels, Offset, Sym))
+  if (std::error_code EC = resolveSymbol(Rels, Offset, Sym))
     return EC;
   const coff_section *Section;
-  if (error_code EC = resolveSectionAndAddress(Obj, Sym, Section, Addr))
+  if (std::error_code EC = resolveSectionAndAddress(Obj, Sym, Section, Addr))
     return EC;
-  if (error_code EC = Obj->getSectionContents(Section, Contents))
+  if (std::error_code EC = Obj->getSectionContents(Section, Contents))
     return EC;
   return object_error::success;
 }
@@ -212,12 +210,12 @@ static error_code getSectionContents(const COFFObjectFile *Obj,
 // Given a vector of relocations for a section and an offset into this section
 // the function returns the name of the symbol used for the relocation at the
 // offset.
-static error_code resolveSymbolName(const std::vector<RelocationRef> &Rels,
-                                    uint64_t Offset, StringRef &Name) {
+static std::error_code resolveSymbolName(const std::vector<RelocationRef> &Rels,
+                                         uint64_t Offset, StringRef &Name) {
   SymbolRef Sym;
-  if (error_code EC = resolveSymbol(Rels, Offset, Sym))
+  if (std::error_code EC = resolveSymbol(Rels, Offset, Sym))
     return EC;
-  if (error_code EC = Sym.getName(Name))
+  if (std::error_code EC = Sym.getName(Name))
     return EC;
   return object_error::success;
 }
diff --git a/tools/llvm-objdump/MachODump.cpp b/tools/llvm-objdump/MachODump.cpp
index cba73183546..21c4c96d4c2 100644
--- a/tools/llvm-objdump/MachODump.cpp
+++ b/tools/llvm-objdump/MachODump.cpp
@@ -42,7 +42,6 @@
 #include <system_error>
 using namespace llvm;
 using namespace object;
-using std::error_code;
 
 static cl::opt<bool>
   UseDbg("g", cl::desc("Print line information from debug info if available"));
@@ -198,7 +197,7 @@ static void DisassembleInputMachO2(StringRef Filename,
 void llvm::DisassembleInputMachO(StringRef Filename) {
   std::unique_ptr<MemoryBuffer> Buff;
 
-  if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, Buff)) {
+  if (std::error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, Buff)) {
     errs() << "llvm-objdump: " << Filename << ": " << ec.message() << "\n";
     return;
   }
@@ -290,7 +289,7 @@ static void DisassembleInputMachO2(StringRef Filename,
     // get the sections and supply it to the section name parsing machinery.
     if (!DSYMFile.empty()) {
       std::unique_ptr<MemoryBuffer> Buf;
-      if (error_code ec = MemoryBuffer::getFileOrSTDIN(DSYMFile, Buf)) {
+      if (std::error_code ec = MemoryBuffer::getFileOrSTDIN(DSYMFile, Buf)) {
         errs() << "llvm-objdump: " << Filename << ": " << ec.message() << '\n';
         return;
       }
diff --git a/tools/llvm-objdump/llvm-objdump.cpp b/tools/llvm-objdump/llvm-objdump.cpp
index 254c802aec4..e12ff3de2bb 100644
--- a/tools/llvm-objdump/llvm-objdump.cpp
+++ b/tools/llvm-objdump/llvm-objdump.cpp
@@ -64,7 +64,6 @@
 
 using namespace llvm;
 using namespace object;
-using std::error_code;
 
 static cl::list<std::string>
 InputFilenames(cl::Positional, cl::desc("<input object files>"),cl::ZeroOrMore);
@@ -149,7 +148,7 @@ YAMLCFG("yaml-cfg",
 
 static StringRef ToolName;
 
-bool llvm::error(error_code EC) {
+bool llvm::error(std::error_code EC) {
   if (!EC)
     return false;
 
@@ -396,7 +395,7 @@ static void DisassembleObject(const ObjectFile *Obj, bool InlineRelocs) {
 
   // Create a mapping, RelocSecs = SectionRelocMap[S], where sections
   // in RelocSecs contain the relocations for section S.
-  error_code EC;
+  std::error_code EC;
   std::map<SectionRef, SmallVector<SectionRef, 1>> SectionRelocMap;
   for (const SectionRef &Section : Obj->sections()) {
     section_iterator Sec2 = Section.getRelocatedSection();
@@ -621,7 +620,7 @@ static void PrintSectionHeaders(const ObjectFile *Obj) {
 }
 
 static void PrintSectionContents(const ObjectFile *Obj) {
-  error_code EC;
+  std::error_code EC;
   for (const SectionRef &Section : Obj->sections()) {
     StringRef Name;
     StringRef Contents;
@@ -852,7 +851,7 @@ static void DumpArchive(const Archive *a) {
   for (Archive::child_iterator i = a->child_begin(), e = a->child_end(); i != e;
        ++i) {
     std::unique_ptr<Binary> child;
-    if (error_code EC = i->getAsBinary(child)) {
+    if (std::error_code EC = i->getAsBinary(child)) {
       // Ignore non-object files.
       if (EC != object_error::invalid_file_type)
         errs() << ToolName << ": '" << a->getFileName() << "': " << EC.message()
@@ -882,7 +881,7 @@ static void DumpInput(StringRef file) {
 
   // Attempt to open the binary.
   ErrorOr<Binary *> BinaryOrErr = createBinary(file);
-  if (error_code EC = BinaryOrErr.getError()) {
+  if (std::error_code EC = BinaryOrErr.getError()) {
     errs() << ToolName << ": '" << file << "': " << EC.message() << ".\n";
     return;
   }
diff --git a/tools/llvm-profdata/llvm-profdata.cpp b/tools/llvm-profdata/llvm-profdata.cpp
index 9bf0897949f..ba88aad9ec7 100644
--- a/tools/llvm-profdata/llvm-profdata.cpp
+++ b/tools/llvm-profdata/llvm-profdata.cpp
@@ -24,7 +24,6 @@
 #include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
-using std::error_code;
 
 static void exitWithError(const Twine &Message, StringRef Whence = "") {
   errs() << "error: ";
@@ -57,11 +56,12 @@ int merge_main(int argc, const char *argv[]) {
   InstrProfWriter Writer;
   for (const auto &Filename : Inputs) {
     std::unique_ptr<InstrProfReader> Reader;
-    if (error_code ec = InstrProfReader::create(Filename, Reader))
+    if (std::error_code ec = InstrProfReader::create(Filename, Reader))
       exitWithError(ec.message(), Filename);
 
     for (const auto &I : *Reader)
-      if (error_code EC = Writer.addFunctionCounts(I.Name, I.Hash, I.Counts))
+      if (std::error_code EC =
+              Writer.addFunctionCounts(I.Name, I.Hash, I.Counts))
         errs() << Filename << ": " << I.Name << ": " << EC.message() << "\n";
     if (Reader->hasError())
       exitWithError(Reader->getError().message(), Filename);
@@ -91,7 +91,7 @@ int show_main(int argc, const char *argv[]) {
   cl::ParseCommandLineOptions(argc, argv, "LLVM profile data summary\n");
 
   std::unique_ptr<InstrProfReader> Reader;
-  if (error_code EC = InstrProfReader::create(Filename, Reader))
+  if (std::error_code EC = InstrProfReader::create(Filename, Reader))
     exitWithError(EC.message(), Filename);
 
   if (OutputFilename.empty())
diff --git a/tools/llvm-readobj/COFFDumper.cpp b/tools/llvm-readobj/COFFDumper.cpp
index 0a14c42fe32..8b0dcb3e2c4 100644
--- a/tools/llvm-readobj/COFFDumper.cpp
+++ b/tools/llvm-readobj/COFFDumper.cpp
@@ -38,7 +38,6 @@
 using namespace llvm;
 using namespace llvm::object;
 using namespace llvm::Win64EH;
-using std::error_code;
 
 namespace {
 
@@ -70,10 +69,10 @@ private:
 
   void cacheRelocations();
 
-  error_code resolveSymbol(const coff_section *Section, uint64_t Offset,
-                           SymbolRef &Sym);
-  error_code resolveSymbolName(const coff_section *Section, uint64_t Offset,
-                               StringRef &Name);
+  std::error_code resolveSymbol(const coff_section *Section, uint64_t Offset,
+                                SymbolRef &Sym);
+  std::error_code resolveSymbolName(const coff_section *Section,
+                                    uint64_t Offset, StringRef &Name);
 
   typedef DenseMap<const coff_section*, std::vector<RelocationRef> > RelocMapTy;
 
@@ -86,8 +85,9 @@ private:
 
 namespace llvm {
 
-error_code createCOFFDumper(const object::ObjectFile *Obj, StreamWriter &Writer,
-                            std::unique_ptr<ObjDumper> &Result) {
+std::error_code createCOFFDumper(const object::ObjectFile *Obj,
+                                 StreamWriter &Writer,
+                                 std::unique_ptr<ObjDumper> &Result) {
   const COFFObjectFile *COFFObj = dyn_cast<COFFObjectFile>(Obj);
   if (!COFFObj)
     return readobj_error::unsupported_obj_file_format;
@@ -100,12 +100,12 @@ error_code createCOFFDumper(const object::ObjectFile *Obj, StreamWriter &Writer,
 
 // Given a a section and an offset into this section the function returns the
 // symbol used for the relocation at the offset.
-error_code COFFDumper::resolveSymbol(const coff_section *Section,
-                                     uint64_t Offset, SymbolRef &Sym) {
+std::error_code COFFDumper::resolveSymbol(const coff_section *Section,
+                                          uint64_t Offset, SymbolRef &Sym) {
   const auto &Relocations = RelocMap[Section];
   for (const auto &Relocation : Relocations) {
     uint64_t RelocationOffset;
-    if (error_code EC = Relocation.getOffset(RelocationOffset))
+    if (std::error_code EC = Relocation.getOffset(RelocationOffset))
       return EC;
 
     if (RelocationOffset == Offset) {
@@ -118,12 +118,13 @@ error_code COFFDumper::resolveSymbol(const coff_section *Section,
 
 // Given a section and an offset into this section the function returns the name
 // of the symbol used for the relocation at the offset.
-error_code COFFDumper::resolveSymbolName(const coff_section *Section,
-                                         uint64_t Offset, StringRef &Name) {
+std::error_code COFFDumper::resolveSymbolName(const coff_section *Section,
+                                              uint64_t Offset,
+                                              StringRef &Name) {
   SymbolRef Symbol;
-  if (error_code EC = resolveSymbol(Section, Offset, Symbol))
+  if (std::error_code EC = resolveSymbol(Section, Offset, Symbol))
     return EC;
-  if (error_code EC = Symbol.getName(Name))
+  if (std::error_code EC = Symbol.getName(Name))
     return EC;
   return object_error::success;
 }
@@ -308,9 +309,10 @@ WeakExternalCharacteristics[] = {
   { "Alias"    , COFF::IMAGE_WEAK_EXTERN_SEARCH_ALIAS     }
 };
 
-template<typename T>
-static error_code getSymbolAuxData(const COFFObjectFile *Obj,
-                                   const coff_symbol *Symbol, const T* &Aux) {
+template <typename T>
+static std::error_code getSymbolAuxData(const COFFObjectFile *Obj,
+                                        const coff_symbol *Symbol,
+                                        const T *&Aux) {
   ArrayRef<uint8_t> AuxData = Obj->getSymbolAuxData(Symbol);
   Aux = reinterpret_cast<const T*>(AuxData.data());
   return readobj_error::success;
@@ -720,7 +722,7 @@ void COFFDumper::printSymbol(const SymbolRef &Sym) {
 
   const coff_symbol *Symbol = Obj->getCOFFSymbol(Sym);
   const coff_section *Section;
-  if (error_code EC = Obj->getSection(Symbol->SectionNumber, Section)) {
+  if (std::error_code EC = Obj->getSection(Symbol->SectionNumber, Section)) {
     W.startLine() << "Invalid section number: " << EC.message() << "\n";
     W.flush();
     return;
@@ -764,7 +766,7 @@ void COFFDumper::printSymbol(const SymbolRef &Sym) {
 
       const coff_symbol *Linked;
       StringRef LinkedName;
-      error_code EC;
+      std::error_code EC;
       if ((EC = Obj->getSymbol(Aux->TagIndex, Linked)) ||
           (EC = Obj->getSymbolName(Linked, LinkedName))) {
         LinkedName = "";
@@ -806,7 +808,7 @@ void COFFDumper::printSymbol(const SymbolRef &Sym) {
           && Aux->Selection == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) {
         const coff_section *Assoc;
         StringRef AssocName;
-        error_code EC;
+        std::error_code EC;
         if ((EC = Obj->getSection(Aux->Number, Assoc)) ||
             (EC = Obj->getSectionName(Assoc, AssocName))) {
           AssocName = "";
@@ -822,7 +824,7 @@ void COFFDumper::printSymbol(const SymbolRef &Sym) {
 
       const coff_symbol *ReferredSym;
       StringRef ReferredName;
-      error_code EC;
+      std::error_code EC;
       if ((EC = Obj->getSymbol(Aux->SymbolTableIndex, ReferredSym)) ||
           (EC = Obj->getSymbolName(ReferredSym, ReferredName))) {
         ReferredName = "";
@@ -850,12 +852,12 @@ void COFFDumper::printUnwindInfo() {
   switch (Header->Machine) {
   case COFF::IMAGE_FILE_MACHINE_AMD64: {
     Win64EH::Dumper Dumper(W);
-    Win64EH::Dumper::SymbolResolver Resolver =
-      [](const object::coff_section *Section, uint64_t Offset,
-         SymbolRef &Symbol, void *user_data) -> error_code {
-        COFFDumper *Dumper = reinterpret_cast<COFFDumper*>(user_data);
-        return Dumper->resolveSymbol(Section, Offset, Symbol);
-      };
+    Win64EH::Dumper::SymbolResolver
+    Resolver = [](const object::coff_section *Section, uint64_t Offset,
+                  SymbolRef &Symbol, void *user_data) -> std::error_code {
+      COFFDumper *Dumper = reinterpret_cast<COFFDumper *>(user_data);
+      return Dumper->resolveSymbol(Section, Offset, Symbol);
+    };
     Win64EH::Dumper::Context Ctx(*Obj, Resolver, this);
     Dumper.printData(Ctx);
     break;
diff --git a/tools/llvm-readobj/ELFDumper.cpp b/tools/llvm-readobj/ELFDumper.cpp
index 8ec59bec008..f13b300d6da 100644
--- a/tools/llvm-readobj/ELFDumper.cpp
+++ b/tools/llvm-readobj/ELFDumper.cpp
@@ -30,7 +30,6 @@
 using namespace llvm;
 using namespace llvm::object;
 using namespace ELF;
-using std::error_code;
 
 #define LLVM_READOBJ_ENUM_CASE(ns, enum) \
   case ns::enum: return #enum;
@@ -82,15 +81,16 @@ template <class T> T errorOrDefault(ErrorOr<T> Val, T Default = T()) {
 namespace llvm {
 
 template <class ELFT>
-static error_code createELFDumper(const ELFFile<ELFT> *Obj,
-                                  StreamWriter &Writer,
-                                  std::unique_ptr<ObjDumper> &Result) {
+static std::error_code createELFDumper(const ELFFile<ELFT> *Obj,
+                                       StreamWriter &Writer,
+                                       std::unique_ptr<ObjDumper> &Result) {
   Result.reset(new ELFDumper<ELFT>(Obj, Writer));
   return readobj_error::success;
 }
 
-error_code createELFDumper(const object::ObjectFile *Obj, StreamWriter &Writer,
-                           std::unique_ptr<ObjDumper> &Result) {
+std::error_code createELFDumper(const object::ObjectFile *Obj,
+                                StreamWriter &Writer,
+                                std::unique_ptr<ObjDumper> &Result) {
   // Little-endian 32-bit
   if (const ELF32LEObjectFile *ELFObj = dyn_cast<ELF32LEObjectFile>(Obj))
     return createELFDumper(ELFObj->getELFFile(), Writer, Result);
diff --git a/tools/llvm-readobj/MachODumper.cpp b/tools/llvm-readobj/MachODumper.cpp
index 0c31bec993d..d168030a270 100644
--- a/tools/llvm-readobj/MachODumper.cpp
+++ b/tools/llvm-readobj/MachODumper.cpp
@@ -21,7 +21,6 @@
 
 using namespace llvm;
 using namespace object;
-using std::error_code;
 
 namespace {
 
@@ -55,9 +54,9 @@ private:
 
 namespace llvm {
 
-error_code createMachODumper(const object::ObjectFile *Obj,
-                             StreamWriter &Writer,
-                             std::unique_ptr<ObjDumper> &Result) {
+std::error_code createMachODumper(const object::ObjectFile *Obj,
+                                  StreamWriter &Writer,
+                                  std::unique_ptr<ObjDumper> &Result) {
   const MachOObjectFile *MachOObj = dyn_cast<MachOObjectFile>(Obj);
   if (!MachOObj)
     return readobj_error::unsupported_obj_file_format;
@@ -278,7 +277,7 @@ void MachODumper::printSections(const MachOObjectFile *Obj) {
 void MachODumper::printRelocations() {
   ListScope D(W, "Relocations");
 
-  error_code EC;
+  std::error_code EC;
   for (const SectionRef &Section : Obj->sections()) {
     StringRef Name;
     if (error(Section.getName(Name)))
diff --git a/tools/llvm-readobj/Win64EHDumper.cpp b/tools/llvm-readobj/Win64EHDumper.cpp
index f3749fc36cc..f058632a8ce 100644
--- a/tools/llvm-readobj/Win64EHDumper.cpp
+++ b/tools/llvm-readobj/Win64EHDumper.cpp
@@ -16,7 +16,6 @@
 using namespace llvm;
 using namespace llvm::object;
 using namespace llvm::Win64EH;
-using std::error_code;
 
 static const EnumEntry<unsigned> UnwindFlags[] = {
   { "ExceptionHandler", UNW_ExceptionHandler },
@@ -135,20 +134,21 @@ static std::string formatSymbol(const Dumper::Context &Ctx,
   return OS.str();
 }
 
-static error_code resolveRelocation(const Dumper::Context &Ctx,
-                                    const coff_section *Section,
-                                    uint64_t Offset,
-                                    const coff_section *&ResolvedSection,
-                                    uint64_t &ResolvedAddress) {
+static std::error_code resolveRelocation(const Dumper::Context &Ctx,
+                                         const coff_section *Section,
+                                         uint64_t Offset,
+                                         const coff_section *&ResolvedSection,
+                                         uint64_t &ResolvedAddress) {
   SymbolRef Symbol;
-  if (error_code EC = Ctx.ResolveSymbol(Section, Offset, Symbol, Ctx.UserData))
+  if (std::error_code EC =
+          Ctx.ResolveSymbol(Section, Offset, Symbol, Ctx.UserData))
     return EC;
 
-  if (error_code EC = Symbol.getAddress(ResolvedAddress))
+  if (std::error_code EC = Symbol.getAddress(ResolvedAddress))
     return EC;
 
   section_iterator SI = Ctx.COFF.section_begin();
-  if (error_code EC = Symbol.getSection(SI))
+  if (std::error_code EC = Symbol.getSection(SI))
     return EC;
 
   ResolvedSection = Ctx.COFF.getCOFFSection(*SI);
diff --git a/tools/llvm-readobj/llvm-readobj.cpp b/tools/llvm-readobj/llvm-readobj.cpp
index 70af4dc4cb4..d66c02f4130 100644
--- a/tools/llvm-readobj/llvm-readobj.cpp
+++ b/tools/llvm-readobj/llvm-readobj.cpp
@@ -41,7 +41,6 @@
 
 using namespace llvm;
 using namespace llvm::object;
-using std::error_code;
 
 namespace opts {
   cl::list<std::string> InputFilenames(cl::Positional,
@@ -142,7 +141,7 @@ static int ReturnValue = EXIT_SUCCESS;
 
 namespace llvm {
 
-bool error(error_code EC) {
+bool error(std::error_code EC) {
   if (!EC)
     return false;
 
@@ -161,8 +160,7 @@ bool relocAddressLess(RelocationRef a, RelocationRef b) {
 
 } // namespace llvm
 
-
-static void reportError(StringRef Input, error_code EC) {
+static void reportError(StringRef Input, std::error_code EC) {
   if (Input == "-")
     Input = "<stdin>";
 
@@ -180,8 +178,8 @@ static void reportError(StringRef Input, StringRef Message) {
 }
 
 /// @brief Creates an format-specific object file dumper.
-static error_code createDumper(const ObjectFile *Obj, StreamWriter &Writer,
-                               std::unique_ptr<ObjDumper> &Result) {
+static std::error_code createDumper(const ObjectFile *Obj, StreamWriter &Writer,
+                                    std::unique_ptr<ObjDumper> &Result) {
   if (!Obj)
     return readobj_error::unsupported_file_format;
 
@@ -200,7 +198,7 @@ static error_code createDumper(const ObjectFile *Obj, StreamWriter &Writer,
 static void dumpObject(const ObjectFile *Obj) {
   StreamWriter Writer(outs());
   std::unique_ptr<ObjDumper> Dumper;
-  if (error_code EC = createDumper(Obj, Writer, Dumper)) {
+  if (std::error_code EC = createDumper(Obj, Writer, Dumper)) {
     reportError(Obj->getFileName(), EC);
     return;
   }
@@ -245,7 +243,7 @@ static void dumpArchive(const Archive *Arc) {
                                ArcE = Arc->child_end();
                                ArcI != ArcE; ++ArcI) {
     std::unique_ptr<Binary> child;
-    if (error_code EC = ArcI->getAsBinary(child)) {
+    if (std::error_code EC = ArcI->getAsBinary(child)) {
       // Ignore non-object files.
       if (EC != object_error::invalid_file_type)
         reportError(Arc->getFileName(), EC.message());
@@ -270,7 +268,7 @@ static void dumpInput(StringRef File) {
 
   // Attempt to open the binary.
   ErrorOr<Binary *> BinaryOrErr = createBinary(File);
-  if (error_code EC = BinaryOrErr.getError()) {
+  if (std::error_code EC = BinaryOrErr.getError()) {
     reportError(File, EC);
     return;
   }
diff --git a/tools/llvm-rtdyld/llvm-rtdyld.cpp b/tools/llvm-rtdyld/llvm-rtdyld.cpp
index e86d93bd490..f1364d53503 100644
--- a/tools/llvm-rtdyld/llvm-rtdyld.cpp
+++ b/tools/llvm-rtdyld/llvm-rtdyld.cpp
@@ -28,7 +28,6 @@
 #include <system_error>
 using namespace llvm;
 using namespace llvm::object;
-using std::error_code;
 
 static cl::list<std::string>
 InputFileList(cl::Positional, cl::ZeroOrMore,
@@ -158,8 +157,8 @@ static int printLineInfoForInput() {
     // Load the input memory buffer.
     std::unique_ptr<MemoryBuffer> InputBuffer;
     std::unique_ptr<ObjectImage> LoadedObject;
-    if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputFileList[i],
-                                                     InputBuffer))
+    if (std::error_code ec =
+            MemoryBuffer::getFileOrSTDIN(InputFileList[i], InputBuffer))
       return Error("unable to read input: '" + ec.message() + "'");
 
     // Load the object file
@@ -219,8 +218,8 @@ static int executeInput() {
     // Load the input memory buffer.
     std::unique_ptr<MemoryBuffer> InputBuffer;
     std::unique_ptr<ObjectImage> LoadedObject;
-    if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputFileList[i],
-                                                     InputBuffer))
+    if (std::error_code ec =
+            MemoryBuffer::getFileOrSTDIN(InputFileList[i], InputBuffer))
       return Error("unable to read input: '" + ec.message() + "'");
 
     // Load the object file
diff --git a/tools/llvm-size/llvm-size.cpp b/tools/llvm-size/llvm-size.cpp
index f0ec7fa6af6..1ea22a937a0 100644
--- a/tools/llvm-size/llvm-size.cpp
+++ b/tools/llvm-size/llvm-size.cpp
@@ -30,7 +30,6 @@
 #include <system_error>
 using namespace llvm;
 using namespace object;
-using std::error_code;
 
 enum OutputFormatTy {berkeley, sysv};
 static cl::opt<OutputFormatTy>
@@ -69,7 +68,7 @@ static cl::list<std::string>
 static std::string ToolName;
 
 ///  @brief If ec is not success, print the error and return true.
-static bool error(error_code ec) {
+static bool error(std::error_code ec) {
   if (!ec) return false;
 
   outs() << ToolName << ": error reading file: " << ec.message() << ".\n";
@@ -236,7 +235,7 @@ static void PrintFileSectionSizes(StringRef file) {
 
   // Attempt to open the binary.
   ErrorOr<Binary *> BinaryOrErr = createBinary(file);
-  if (error_code EC = BinaryOrErr.getError()) {
+  if (std::error_code EC = BinaryOrErr.getError()) {
     errs() << ToolName << ": " << file << ": " << EC.message() << ".\n";
     return;
   }
@@ -247,7 +246,7 @@ static void PrintFileSectionSizes(StringRef file) {
     for (object::Archive::child_iterator i = a->child_begin(),
                                          e = a->child_end(); i != e; ++i) {
       std::unique_ptr<Binary> child;
-      if (error_code ec = i->getAsBinary(child)) {
+      if (std::error_code ec = i->getAsBinary(child)) {
         errs() << ToolName << ": " << file << ": " << ec.message() << ".\n";
         continue;
       }
diff --git a/tools/llvm-symbolizer/LLVMSymbolize.cpp b/tools/llvm-symbolizer/LLVMSymbolize.cpp
index 61c4e8ad209..c6bd4e7abfc 100644
--- a/tools/llvm-symbolizer/LLVMSymbolize.cpp
+++ b/tools/llvm-symbolizer/LLVMSymbolize.cpp
@@ -26,10 +26,9 @@
 #include <stdlib.h>
 
 namespace llvm {
-using std::error_code;
 namespace symbolize {
 
-static bool error(error_code ec) {
+static bool error(std::error_code ec) {
   if (!ec)
     return false;
   errs() << "LLVMSymbolizer: error reading file: " << ec.message() << ".\n";
@@ -311,7 +310,7 @@ LLVMSymbolizer::getOrCreateBinary(const std::string &Path) {
       const std::string &ResourcePath =
           getDarwinDWARFResourceForPath(Path);
       BinaryOrErr = createBinary(ResourcePath);
-      error_code EC = BinaryOrErr.getError();
+      std::error_code EC = BinaryOrErr.getError();
       if (EC != std::errc::no_such_file_or_directory && !error(EC)) {
         DbgBin = BinaryOrErr.get();
         ParsedBinariesAndObjects.push_back(std::unique_ptr<Binary>(DbgBin));
diff --git a/tools/llvm-symbolizer/llvm-symbolizer.cpp b/tools/llvm-symbolizer/llvm-symbolizer.cpp
index 2ee30e816e4..29db172531b 100644
--- a/tools/llvm-symbolizer/llvm-symbolizer.cpp
+++ b/tools/llvm-symbolizer/llvm-symbolizer.cpp
@@ -29,7 +29,6 @@
 
 using namespace llvm;
 using namespace symbolize;
-using std::error_code;
 
 static cl::opt<bool>
 ClUseSymbolTable("use-symbol-table", cl::init(true),
diff --git a/tools/macho-dump/macho-dump.cpp b/tools/macho-dump/macho-dump.cpp
index 13e8a4b80ca..bfe1a6eaef4 100644
--- a/tools/macho-dump/macho-dump.cpp
+++ b/tools/macho-dump/macho-dump.cpp
@@ -23,7 +23,6 @@
 #include <system_error>
 using namespace llvm;
 using namespace llvm::object;
-using std::error_code;
 
 static cl::opt<std::string>
 InputFile(cl::Positional, cl::desc("<input file>"), cl::init("-"));
@@ -392,7 +391,7 @@ int main(int argc, char **argv) {
   cl::ParseCommandLineOptions(argc, argv, "llvm Mach-O dumping tool\n");
 
   ErrorOr<Binary *> BinaryOrErr = createBinary(InputFile);
-  if (error_code EC = BinaryOrErr.getError())
+  if (std::error_code EC = BinaryOrErr.getError())
     return Error("unable to read input: '" + EC.message() + "'");
   std::unique_ptr<Binary> Binary(BinaryOrErr.get());
 
diff --git a/tools/obj2yaml/coff2yaml.cpp b/tools/obj2yaml/coff2yaml.cpp
index 816f9e65cde..48462f69fc5 100644
--- a/tools/obj2yaml/coff2yaml.cpp
+++ b/tools/obj2yaml/coff2yaml.cpp
@@ -14,7 +14,6 @@
 #include "llvm/Support/YAMLTraits.h"
 
 using namespace llvm;
-using std::error_code;
 
 namespace {
 
@@ -32,7 +31,7 @@ public:
 
 }
 
-static void check(error_code ec) {
+static void check(std::error_code ec) {
   if (ec)
     report_fatal_error(ec.message());
 }
@@ -211,7 +210,7 @@ COFFYAML::Object &COFFDumper::getYAMLObj() {
   return YAMLObj;
 }
 
-error_code coff2yaml(raw_ostream &Out, const object::COFFObjectFile &Obj) {
+std::error_code coff2yaml(raw_ostream &Out, const object::COFFObjectFile &Obj) {
   COFFDumper Dumper(Obj);
 
   yaml::Output Yout(Out);
diff --git a/tools/obj2yaml/elf2yaml.cpp b/tools/obj2yaml/elf2yaml.cpp
index a20ad6f3e2c..c817e1526da 100644
--- a/tools/obj2yaml/elf2yaml.cpp
+++ b/tools/obj2yaml/elf2yaml.cpp
@@ -16,7 +16,6 @@
 #include "llvm/Support/YAMLTraits.h"
 
 using namespace llvm;
-using std::error_code;
 
 namespace {
 
@@ -27,13 +26,13 @@ class ELFDumper {
 
   const object::ELFFile<ELFT> &Obj;
 
-  error_code dumpSymbol(Elf_Sym_Iter Sym, ELFYAML::Symbol &S);
-  error_code dumpCommonSection(const Elf_Shdr *Shdr, ELFYAML::Section &S);
-  error_code dumpCommonRelocationSection(const Elf_Shdr *Shdr,
-                                         ELFYAML::RelocationSection &S);
+  std::error_code dumpSymbol(Elf_Sym_Iter Sym, ELFYAML::Symbol &S);
+  std::error_code dumpCommonSection(const Elf_Shdr *Shdr, ELFYAML::Section &S);
+  std::error_code dumpCommonRelocationSection(const Elf_Shdr *Shdr,
+                                              ELFYAML::RelocationSection &S);
   template <class RelT>
-  error_code dumpRelocation(const Elf_Shdr *Shdr, const RelT *Rel,
-                            ELFYAML::Relocation &R);
+  std::error_code dumpRelocation(const Elf_Shdr *Shdr, const RelT *Rel,
+                                 ELFYAML::Relocation &R);
 
   ErrorOr<ELFYAML::RelocationSection *> dumpRelSection(const Elf_Shdr *Shdr);
   ErrorOr<ELFYAML::RelocationSection *> dumpRelaSection(const Elf_Shdr *Shdr);
@@ -75,14 +74,14 @@ ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
       break;
     case ELF::SHT_RELA: {
       ErrorOr<ELFYAML::RelocationSection *> S = dumpRelaSection(&Sec);
-      if (error_code EC = S.getError())
+      if (std::error_code EC = S.getError())
         return EC;
       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
       break;
     }
     case ELF::SHT_REL: {
       ErrorOr<ELFYAML::RelocationSection *> S = dumpRelSection(&Sec);
-      if (error_code EC = S.getError())
+      if (std::error_code EC = S.getError())
         return EC;
       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
       break;
@@ -90,7 +89,7 @@ ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
     // FIXME: Support SHT_GROUP section format.
     default: {
       ErrorOr<ELFYAML::RawContentSection *> S = dumpContentSection(&Sec);
-      if (error_code EC = S.getError())
+      if (std::error_code EC = S.getError())
         return EC;
       Y->Sections.push_back(std::unique_ptr<ELFYAML::Section>(S.get()));
     }
@@ -106,7 +105,7 @@ ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
     }
 
     ELFYAML::Symbol S;
-    if (error_code EC = ELFDumper<ELFT>::dumpSymbol(SI, S))
+    if (std::error_code EC = ELFDumper<ELFT>::dumpSymbol(SI, S))
       return EC;
 
     switch (SI->getBinding())
@@ -129,14 +128,15 @@ ErrorOr<ELFYAML::Object *> ELFDumper<ELFT>::dump() {
 }
 
 template <class ELFT>
-error_code ELFDumper<ELFT>::dumpSymbol(Elf_Sym_Iter Sym, ELFYAML::Symbol &S) {
+std::error_code ELFDumper<ELFT>::dumpSymbol(Elf_Sym_Iter Sym,
+                                            ELFYAML::Symbol &S) {
   S.Type = Sym->getType();
   S.Value = Sym->st_value;
   S.Size = Sym->st_size;
   S.Visibility = Sym->st_other & 0x3;
 
   ErrorOr<StringRef> NameOrErr = Obj.getSymbolName(Sym);
-  if (error_code EC = NameOrErr.getError())
+  if (std::error_code EC = NameOrErr.getError())
     return EC;
   S.Name = NameOrErr.get();
 
@@ -145,7 +145,7 @@ error_code ELFDumper<ELFT>::dumpSymbol(Elf_Sym_Iter Sym, ELFYAML::Symbol &S) {
     return obj2yaml_error::success;
 
   NameOrErr = Obj.getSectionName(Shdr);
-  if (error_code EC = NameOrErr.getError())
+  if (std::error_code EC = NameOrErr.getError())
     return EC;
   S.Section = NameOrErr.get();
 
@@ -154,9 +154,9 @@ error_code ELFDumper<ELFT>::dumpSymbol(Elf_Sym_Iter Sym, ELFYAML::Symbol &S) {
 
 template <class ELFT>
 template <class RelT>
-error_code ELFDumper<ELFT>::dumpRelocation(const Elf_Shdr *Shdr,
-                                           const RelT *Rel,
-                                           ELFYAML::Relocation &R) {
+std::error_code ELFDumper<ELFT>::dumpRelocation(const Elf_Shdr *Shdr,
+                                                const RelT *Rel,
+                                                ELFYAML::Relocation &R) {
   R.Type = Rel->getType(Obj.isMips64EL());
   R.Offset = Rel->r_offset;
   R.Addend = 0;
@@ -167,7 +167,7 @@ error_code ELFDumper<ELFT>::dumpRelocation(const Elf_Shdr *Shdr,
 
   ErrorOr<StringRef> NameOrErr =
       Obj.getSymbolName(NamePair.first, NamePair.second);
-  if (error_code EC = NameOrErr.getError())
+  if (std::error_code EC = NameOrErr.getError())
     return EC;
   R.Symbol = NameOrErr.get();
 
@@ -175,22 +175,22 @@ error_code ELFDumper<ELFT>::dumpRelocation(const Elf_Shdr *Shdr,
 }
 
 template <class ELFT>
-error_code ELFDumper<ELFT>::dumpCommonSection(const Elf_Shdr *Shdr,
-                                              ELFYAML::Section &S) {
+std::error_code ELFDumper<ELFT>::dumpCommonSection(const Elf_Shdr *Shdr,
+                                                   ELFYAML::Section &S) {
   S.Type = Shdr->sh_type;
   S.Flags = Shdr->sh_flags;
   S.Address = Shdr->sh_addr;
   S.AddressAlign = Shdr->sh_addralign;
 
   ErrorOr<StringRef> NameOrErr = Obj.getSectionName(Shdr);
-  if (error_code EC = NameOrErr.getError())
+  if (std::error_code EC = NameOrErr.getError())
     return EC;
   S.Name = NameOrErr.get();
 
   if (Shdr->sh_link != ELF::SHN_UNDEF) {
     if (const Elf_Shdr *LinkSection = Obj.getSection(Shdr->sh_link)) {
       NameOrErr = Obj.getSectionName(LinkSection);
-      if (error_code EC = NameOrErr.getError())
+      if (std::error_code EC = NameOrErr.getError())
         return EC;
       S.Link = NameOrErr.get();
     }
@@ -200,15 +200,15 @@ error_code ELFDumper<ELFT>::dumpCommonSection(const Elf_Shdr *Shdr,
 }
 
 template <class ELFT>
-error_code
+std::error_code
 ELFDumper<ELFT>::dumpCommonRelocationSection(const Elf_Shdr *Shdr,
                                              ELFYAML::RelocationSection &S) {
-  if (error_code EC = dumpCommonSection(Shdr, S))
+  if (std::error_code EC = dumpCommonSection(Shdr, S))
     return EC;
 
   if (const Elf_Shdr *InfoSection = Obj.getSection(Shdr->sh_info)) {
     ErrorOr<StringRef> NameOrErr = Obj.getSectionName(InfoSection);
-    if (error_code EC = NameOrErr.getError())
+    if (std::error_code EC = NameOrErr.getError())
       return EC;
     S.Info = NameOrErr.get();
   }
@@ -222,13 +222,13 @@ ELFDumper<ELFT>::dumpRelSection(const Elf_Shdr *Shdr) {
   assert(Shdr->sh_type == ELF::SHT_REL && "Section type is not SHT_REL");
   auto S = make_unique<ELFYAML::RelocationSection>();
 
-  if (error_code EC = dumpCommonRelocationSection(Shdr, *S))
+  if (std::error_code EC = dumpCommonRelocationSection(Shdr, *S))
     return EC;
 
   for (auto RI = Obj.begin_rel(Shdr), RE = Obj.end_rel(Shdr); RI != RE;
        ++RI) {
     ELFYAML::Relocation R;
-    if (error_code EC = dumpRelocation(Shdr, &*RI, R))
+    if (std::error_code EC = dumpRelocation(Shdr, &*RI, R))
       return EC;
     S->Relocations.push_back(R);
   }
@@ -242,13 +242,13 @@ ELFDumper<ELFT>::dumpRelaSection(const Elf_Shdr *Shdr) {
   assert(Shdr->sh_type == ELF::SHT_RELA && "Section type is not SHT_RELA");
   auto S = make_unique<ELFYAML::RelocationSection>();
 
-  if (error_code EC = dumpCommonRelocationSection(Shdr, *S))
+  if (std::error_code EC = dumpCommonRelocationSection(Shdr, *S))
     return EC;
 
   for (auto RI = Obj.begin_rela(Shdr), RE = Obj.end_rela(Shdr); RI != RE;
        ++RI) {
     ELFYAML::Relocation R;
-    if (error_code EC = dumpRelocation(Shdr, &*RI, R))
+    if (std::error_code EC = dumpRelocation(Shdr, &*RI, R))
       return EC;
     R.Addend = RI->r_addend;
     S->Relocations.push_back(R);
@@ -262,11 +262,11 @@ ErrorOr<ELFYAML::RawContentSection *>
 ELFDumper<ELFT>::dumpContentSection(const Elf_Shdr *Shdr) {
   auto S = make_unique<ELFYAML::RawContentSection>();
 
-  if (error_code EC = dumpCommonSection(Shdr, *S))
+  if (std::error_code EC = dumpCommonSection(Shdr, *S))
     return EC;
 
   ErrorOr<ArrayRef<uint8_t>> ContentOrErr = Obj.getSectionContents(Shdr);
-  if (error_code EC = ContentOrErr.getError())
+  if (std::error_code EC = ContentOrErr.getError())
     return EC;
   S->Content = object::yaml::BinaryRef(ContentOrErr.get());
   S->Size = S->Content.binary_size();
@@ -275,10 +275,11 @@ ELFDumper<ELFT>::dumpContentSection(const Elf_Shdr *Shdr) {
 }
 
 template <class ELFT>
-static error_code elf2yaml(raw_ostream &Out, const object::ELFFile<ELFT> &Obj) {
+static std::error_code elf2yaml(raw_ostream &Out,
+                                const object::ELFFile<ELFT> &Obj) {
   ELFDumper<ELFT> Dumper(Obj);
   ErrorOr<ELFYAML::Object *> YAMLOrErr = Dumper.dump();
-  if (error_code EC = YAMLOrErr.getError())
+  if (std::error_code EC = YAMLOrErr.getError())
     return EC;
 
   std::unique_ptr<ELFYAML::Object> YAML(YAMLOrErr.get());
@@ -288,7 +289,7 @@ static error_code elf2yaml(raw_ostream &Out, const object::ELFFile<ELFT> &Obj) {
   return object::object_error::success;
 }
 
-error_code elf2yaml(raw_ostream &Out, const object::ObjectFile &Obj) {
+std::error_code elf2yaml(raw_ostream &Out, const object::ObjectFile &Obj) {
   if (const auto *ELFObj = dyn_cast<object::ELF32LEObjectFile>(&Obj))
     return elf2yaml(Out, *ELFObj->getELFFile());
 
diff --git a/tools/obj2yaml/obj2yaml.cpp b/tools/obj2yaml/obj2yaml.cpp
index 717c68d1c63..944314a923f 100644
--- a/tools/obj2yaml/obj2yaml.cpp
+++ b/tools/obj2yaml/obj2yaml.cpp
@@ -18,9 +18,8 @@
 
 using namespace llvm;
 using namespace llvm::object;
-using std::error_code;
 
-static error_code dumpObject(const ObjectFile &Obj) {
+static std::error_code dumpObject(const ObjectFile &Obj) {
   if (Obj.isCOFF())
     return coff2yaml(outs(), cast<COFFObjectFile>(Obj));
   if (Obj.isELF())
@@ -29,12 +28,12 @@ static error_code dumpObject(const ObjectFile &Obj) {
   return obj2yaml_error::unsupported_obj_file_format;
 }
 
-static error_code dumpInput(StringRef File) {
+static std::error_code dumpInput(StringRef File) {
   if (File != "-" && !sys::fs::exists(File))
     return obj2yaml_error::file_not_found;
 
   ErrorOr<Binary *> BinaryOrErr = createBinary(File);
-  if (error_code EC = BinaryOrErr.getError())
+  if (std::error_code EC = BinaryOrErr.getError())
     return EC;
 
   std::unique_ptr<Binary> Binary(BinaryOrErr.get());
@@ -54,7 +53,7 @@ int main(int argc, char *argv[]) {
   PrettyStackTraceProgram X(argc, argv);
   llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
 
-  if (error_code EC = dumpInput(InputFilename)) {
+  if (std::error_code EC = dumpInput(InputFilename)) {
     errs() << "Error: '" << EC.message() << "'\n";
     return 1;
   }