raw_ostream: add operator<< overload for std::error_code

Summary:
The main motivation for this is unit tests, which contain a large macro
for pretty-printing std::error_code, and this macro is duplicated in
every file that needs to do this. However, the functionality may be
useful elsewhere too.

In this patch I have reimplemented the existing ASSERT_NO_ERROR macros
to reuse the new functionality, but I have kept the macro (as a
one-liner) as it is slightly more readable than ASSERT_EQ(...,
std::error_code()).

Reviewers: sammccall, ilya-biryukov

Subscribers: zturner, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65643

llvm-svn: 368849

include/llvm/Support/raw_ostream.h

@@ -223,6 +223,8 @@ public:
 
   raw_ostream &operator<<(double N);
 
+  raw_ostream &operator<<(std::error_code EC);
+
   /// Output \p N in hexadecimal, without any prefix or padding.
   raw_ostream &write_hex(unsigned long long N);
 

lib/Support/raw_ostream.cpp

@@ -139,6 +139,11 @@ raw_ostream &raw_ostream::operator<<(long long N) {
   return *this;
 }
 
+raw_ostream &raw_ostream::operator<<(std::error_code EC) {
+  return *this << EC.message() << " (" << EC.category().name() << ':'
+               << EC.value() << ')';
+}
+
 raw_ostream &raw_ostream::write_hex(unsigned long long N) {
   llvm::write_hex(*this, N, HexPrintStyle::Lower);
   return *this;

unittests/BinaryFormat/TestFileMagic.cpp

@@ -17,16 +17,7 @@
 using namespace llvm;
 namespace fs = llvm::sys::fs;
 
-#define ASSERT_NO_ERROR(x)                                                     \
+#define ASSERT_NO_ERROR(x) ASSERT_EQ(x, std::error_code())
-  if (std::error_code ASSERT_NO_ERROR_ec = x) {                                \
-    SmallString<128> MessageStorage;                                           \
-    raw_svector_ostream Message(MessageStorage);                               \
-    Message << #x ": did not return errc::success.\n"                          \
-            << "error number: " << ASSERT_NO_ERROR_ec.value() << "\n"          \
-            << "error message: " << ASSERT_NO_ERROR_ec.message() << "\n";      \
-    GTEST_FATAL_FAILURE_(MessageStorage.c_str());                              \
-  } else {                                                                     \
-  }
 
 class MagicTest : public testing::Test {
 protected:

unittests/Support/ErrorTest.cpp

@@ -933,7 +933,7 @@ public:
 
 class TestErrorCategory : public std::error_category {
 public:
-  const char *name() const noexcept override { return "error"; }
+  const char *name() const noexcept override { return "test_error"; }
   std::string message(int Condition) const override {
     switch (static_cast<test_error_code>(Condition)) {
     case test_error_code::unspecified:
@@ -975,4 +975,11 @@ TEST(Error, SubtypeStringErrorTest) {
             0);
 }
 
+TEST(Error, error_codeErrorMessageTest) {
+  EXPECT_NONFATAL_FAILURE(
+      EXPECT_EQ(make_error_code(test_error_code::unspecified),
+                make_error_code(test_error_code::error_2)),
+      "Which is: An unknown error has occurred. (test_error:1)");
+}
+
 } // namespace

unittests/Support/FileOutputBufferTest.cpp

@@ -18,16 +18,7 @@
 using namespace llvm;
 using namespace llvm::sys;
 
-#define ASSERT_NO_ERROR(x)                                                     \
+#define ASSERT_NO_ERROR(x) ASSERT_EQ(x, std::error_code())
-  if (std::error_code ASSERT_NO_ERROR_ec = x) {                                \
-    SmallString<128> MessageStorage;                                           \
-    raw_svector_ostream Message(MessageStorage);                               \
-    Message << #x ": did not return errc::success.\n"                          \
-            << "error number: " << ASSERT_NO_ERROR_ec.value() << "\n"          \
-            << "error message: " << ASSERT_NO_ERROR_ec.message() << "\n";      \
-    GTEST_FATAL_FAILURE_(MessageStorage.c_str());                              \
-  } else {                                                                     \
-  }
 
 namespace {
 TEST(FileOutputBuffer, Test) {

unittests/Support/Host.cpp

@@ -16,16 +16,7 @@
 
 #include "gtest/gtest.h"
 
-#define ASSERT_NO_ERROR(x)                                                     \
+#define ASSERT_NO_ERROR(x) ASSERT_EQ(x, std::error_code())
-  if (std::error_code ASSERT_NO_ERROR_ec = x) {                                \
-    SmallString<128> MessageStorage;                                           \
-    raw_svector_ostream Message(MessageStorage);                               \
-    Message << #x ": did not return errc::success.\n"                          \
-            << "error number: " << ASSERT_NO_ERROR_ec.value() << "\n"          \
-            << "error message: " << ASSERT_NO_ERROR_ec.message() << "\n";      \
-    GTEST_FATAL_FAILURE_(MessageStorage.c_str());                              \
-  } else {                                                                     \
-  }
 
 using namespace llvm;
 

unittests/Support/Path.cpp

@@ -38,24 +38,8 @@
 using namespace llvm;
 using namespace llvm::sys;
 
-#define ASSERT_NO_ERROR(x)                                                     \
+#define ASSERT_NO_ERROR(x) ASSERT_EQ(x, std::error_code())
-  if (std::error_code ASSERT_NO_ERROR_ec = x) {                                \
+#define ASSERT_ERROR(x) ASSERT_NE(x, std::error_code())
-    SmallString<128> MessageStorage;                                           \
-    raw_svector_ostream Message(MessageStorage);                               \
-    Message << #x ": did not return errc::success.\n"                          \
-            << "error number: " << ASSERT_NO_ERROR_ec.value() << "\n"          \
-            << "error message: " << ASSERT_NO_ERROR_ec.message() << "\n";      \
-    GTEST_FATAL_FAILURE_(MessageStorage.c_str());                              \
-  } else {                                                                     \
-  }
-
-#define ASSERT_ERROR(x)                                                        \
-  if (!x) {                                                                    \
-    SmallString<128> MessageStorage;                                           \
-    raw_svector_ostream Message(MessageStorage);                               \
-    Message << #x ": did not return a failure error code.\n";                  \
-    GTEST_FATAL_FAILURE_(MessageStorage.c_str());                              \
-  }
 
 namespace {
 
@@ -1265,7 +1249,7 @@ TEST_F(FileSystemTest, OpenFileForRead) {
   int FileDescriptor2;
   SmallString<64> ResultPath;
   ASSERT_NO_ERROR(fs::openFileForRead(Twine(TempPath), FileDescriptor2,
-                                      fs::OF_None, &ResultPath))
+                                      fs::OF_None, &ResultPath));
 
   // If we succeeded, check that the paths are the same (modulo case):
   if (!ResultPath.empty()) {

unittests/Support/ProgramTest.cpp

@@ -35,16 +35,8 @@ void sleep_for(unsigned int seconds) {
 #error sleep_for is not implemented on your platform.
 #endif
 
-#define ASSERT_NO_ERROR(x)                                                     \
+#define ASSERT_NO_ERROR(x) ASSERT_EQ(x, std::error_code())
-  if (std::error_code ASSERT_NO_ERROR_ec = x) {                                \
+
-    SmallString<128> MessageStorage;                                           \
-    raw_svector_ostream Message(MessageStorage);                               \
-    Message << #x ": did not return errc::success.\n"                          \
-            << "error number: " << ASSERT_NO_ERROR_ec.value() << "\n"          \
-            << "error message: " << ASSERT_NO_ERROR_ec.message() << "\n";      \
-    GTEST_FATAL_FAILURE_(MessageStorage.c_str());                              \
-  } else {                                                                     \
-  }
 // From TestMain.cpp.
 extern const char *TestMainArgv0;
 

unittests/Support/ReplaceFileTest.cpp

@@ -17,14 +17,7 @@
 using namespace llvm;
 using namespace llvm::sys;
 
-#define ASSERT_NO_ERROR(x)                                                 \
+#define ASSERT_NO_ERROR(x) ASSERT_EQ(x, std::error_code())
-  do {                                                                     \
-    if (std::error_code ASSERT_NO_ERROR_ec = x) {                          \
-      errs() << #x ": did not return errc::success.\n"                     \
-             << "error number: " << ASSERT_NO_ERROR_ec.value() << "\n"     \
-             << "error message: " << ASSERT_NO_ERROR_ec.message() << "\n"; \
-    }                                                                      \
-  } while (false)
 
 namespace {
 std::error_code CreateFileWithContent(const SmallString<128> &FilePath,

unittests/Support/raw_pwrite_stream_test.cpp

@@ -15,16 +15,7 @@
 
 using namespace llvm;
 
-#define ASSERT_NO_ERROR(x)                                                     \
+#define ASSERT_NO_ERROR(x) ASSERT_EQ(x, std::error_code())
-  if (std::error_code ASSERT_NO_ERROR_ec = x) {                                \
-    SmallString<128> MessageStorage;                                           \
-    raw_svector_ostream Message(MessageStorage);                               \
-    Message << #x ": did not return errc::success.\n"                          \
-            << "error number: " << ASSERT_NO_ERROR_ec.value() << "\n"          \
-            << "error message: " << ASSERT_NO_ERROR_ec.message() << "\n";      \
-    GTEST_FATAL_FAILURE_(MessageStorage.c_str());                              \
-  } else {                                                                     \
-  }
 
 namespace {