Improve char printing (pytorch#167899)

This PR outputs chars to stream without building temporary strings.
They were modified by (on fish)
```
sed  -i -e 's/<< "\([^\\\']\)"/<< \'\1\'/g' (grep '<< "."' -r torch c10 aten -l)
```
and revert some invalid changes.

Pull Request resolved: pytorch#167899
Approved by: https://github.com/Skylion007

Author: cyyever

aten/src/ATen/LegacyBatchedTensorImpl.h

@@ -144,7 +144,7 @@ inline std::bitset<kVmapNumLevels> createVmapLevelsBitset(BatchDimsRef bdims) {
 }
 
 inline std::ostream& operator<<(std::ostream& out, const BatchDim& bdim) {
-  out << "(lvl=" << bdim.level() << ", dim=" << bdim.dim() << ")";
+  out << "(lvl=" << bdim.level() << ", dim=" << bdim.dim() << ')';
   return out;
 }
 

aten/src/ATen/TensorIndexing.cpp

@@ -9,7 +9,7 @@ namespace indexing {
 const EllipsisIndexType Ellipsis = EllipsisIndexType();
 
 std::ostream& operator<<(std::ostream& stream, const Slice& slice) {
-  stream << slice.start() << ":" << slice.stop() << ":" << slice.step();
+  stream << slice.start() << ':' << slice.stop() << ':' << slice.step();
   return stream;
 }
 
@@ -31,12 +31,12 @@ std::ostream& operator<<(std::ostream& stream, const TensorIndex& tensor_index)
 }
 
 std::ostream& operator<<(std::ostream& stream, const std::vector<TensorIndex>& tensor_indices) {
-  stream << "(";
+  stream << '(';
   for (const auto i : c10::irange(tensor_indices.size())) {
     stream << tensor_indices[i];
     if (i < tensor_indices.size() - 1) stream << ", ";
   }
-  stream << ")";
+  stream << ')';
   return stream;
 }
 

aten/src/ATen/TensorNames.cpp

@@ -113,7 +113,7 @@ void TensorNames::checkUnique(const char* op_name) const {
 std::ostream& operator<<(std::ostream& out, const TensorName& tensorname) {
   out << tensorname.name_ << " (index ";
   out << tensorname.origin_idx_ << " of ";
-  out << tensorname.origin_ << ")";
+  out << tensorname.origin_ << ')';
   return out;
 }
 

aten/src/ATen/TensorUtils.cpp

@@ -13,9 +13,9 @@ std::ostream& operator<<(std::ostream & out, const TensorGeometryArg& t) {
   if (t.pos == 0) {
     // 0 is distinguished; it usually indicates 'self' or the return
     // tensor
-    out << "'" << t.name << "'";
+    out << '\'' << t.name << '\'';
   } else {
-    out << "argument #" << t.pos << " '" << t.name << "'";
+    out << "argument #" << t.pos << " '" << t.name << '\'';
   }
   return out;
 }
@@ -154,7 +154,7 @@ void checkSameGPU(CheckedFrom c, const TensorArg& t1, const TensorArg& t2) {
       oss << "Tensor for " << t2 << " is on CPU, ";
     }
     oss << "but expected " << ((!t1->is_cpu() && !t2->is_cpu()) ? "them" : "it")
-        << " to be on GPU (while checking arguments for " << c << ")";
+        << " to be on GPU (while checking arguments for " << c << ')';
     TORCH_CHECK(false, oss.str());
   }
   TORCH_CHECK(
@@ -199,7 +199,7 @@ void checkScalarTypes(CheckedFrom c, const TensorArg& t,
         i++;
       }
       oss << "; but got " << t->toString()
-          << " instead (while checking arguments for " << c << ")";
+          << " instead (while checking arguments for " << c << ')';
       TORCH_CHECK(false, oss.str());
     }
 }

aten/src/ATen/Version.cpp

@@ -43,8 +43,8 @@ std::string get_mkldnn_version() {
     // https://github.com/intel/ideep/issues/29
     {
       const dnnl_version_t* ver = dnnl_version();
-      ss << "Intel(R) MKL-DNN v" << ver->major << "." << ver->minor << "." << ver->patch
-         << " (Git Hash " << ver->hash << ")";
+      ss << "Intel(R) MKL-DNN v" << ver->major << '.' << ver->minor << '.' << ver->patch
+         << " (Git Hash " << ver->hash << ')';
     }
   #else
     ss << "MKLDNN not found";
@@ -81,7 +81,7 @@ std::string get_openmp_version() {
           break;
       }
       if (ver_str) {
-        ss << " (a.k.a. OpenMP " << ver_str << ")";
+        ss << " (a.k.a. OpenMP " << ver_str << ')';
       }
     }
   #else
@@ -135,38 +135,38 @@ std::string show_config() {
 
 #if defined(__GNUC__)
   {
-    ss << "  - GCC " << __GNUC__ << "." << __GNUC_MINOR__ << "\n";
+    ss << "  - GCC " << __GNUC__ << '.' << __GNUC_MINOR__ << '\n';
   }
 #endif
 
 #if defined(__cplusplus)
   {
-    ss << "  - C++ Version: " << __cplusplus << "\n";
+    ss << "  - C++ Version: " << __cplusplus << '\n';
   }
 #endif
 
 #if defined(__clang_major__)
   {
-    ss << "  - clang " << __clang_major__ << "." << __clang_minor__ << "." << __clang_patchlevel__ << "\n";
+    ss << "  - clang " << __clang_major__ << '.' << __clang_minor__ << '.' << __clang_patchlevel__ << '\n';
   }
 #endif
 
 #if defined(_MSC_VER)
   {
-    ss << "  - MSVC " << _MSC_FULL_VER << "\n";
+    ss << "  - MSVC " << _MSC_FULL_VER << '\n';
   }
 #endif
 
 #if AT_MKL_ENABLED()
-  ss << "  - " << get_mkl_version() << "\n";
+  ss << "  - " << get_mkl_version() << '\n';
 #endif
 
 #if AT_MKLDNN_ENABLED()
-  ss << "  - " << get_mkldnn_version() << "\n";
+  ss << "  - " << get_mkldnn_version() << '\n';
 #endif
 
 #ifdef _OPENMP
-  ss << "  - " << get_openmp_version() << "\n";
+  ss << "  - " << get_openmp_version() << '\n';
 #endif
 
 #if AT_BUILD_WITH_LAPACK()
@@ -183,7 +183,7 @@ std::string show_config() {
   ss << "  - Cross compiling on MacOSX\n";
 #endif
 
-  ss << "  - "<< used_cpu_capability() << "\n";
+  ss << "  - "<< used_cpu_capability() << '\n';
 
   if (hasCUDA()) {
     ss << detail::getCUDAHooks().showConfig();
@@ -200,10 +200,10 @@ std::string show_config() {
   ss << "  - Build settings: ";
   for (const auto& pair : caffe2::GetBuildOptions()) {
     if (!pair.second.empty()) {
-      ss << pair.first << "=" << pair.second << ", ";
+      ss << pair.first << '=' << pair.second << ", ";
     }
   }
-  ss << "\n";
+  ss << '\n';
 
   // TODO: do HIP
   // TODO: do XLA

aten/src/ATen/code_template.h

@@ -209,7 +209,7 @@ struct CodeTemplate {
   // to indent correctly in the context.
   void emitIndent(std::ostream& out, size_t indent) const {
     for ([[maybe_unused]] const auto i : c10::irange(indent)) {
-      out << " ";
+      out << ' ';
     }
   }
   void emitStringWithIndents(

aten/src/ATen/core/Dimname.cpp

@@ -10,7 +10,7 @@ std::ostream& operator<<(std::ostream& out, const Dimname& dimname) {
   if (dimname.type() == NameType::WILDCARD) {
     out << "None";
   } else {
-    out << "'" << dimname.symbol().toUnqualString() << "'";
+    out << '\'' << dimname.symbol().toUnqualString() << '\'';
   }
   return out;
 }

aten/src/ATen/core/Range.cpp

@@ -5,7 +5,7 @@
 namespace at {
 
 std::ostream& operator<<(std::ostream& out, const Range& range) {
-  out << "Range[" << range.begin << ", " << range.end << "]";
+  out << "Range[" << range.begin << ", " << range.end << ']';
   return out;
 }
 

aten/src/ATen/core/Tensor.cpp

@@ -71,7 +71,7 @@ void TensorBase::enforce_invariants() {
 
 void TensorBase::print() const {
   if (defined()) {
-    std::cerr << "[" << toString() << " " << sizes() << "]" << '\n';
+    std::cerr << '[' << toString() << ' ' << sizes() << ']' << '\n';
   } else {
     std::cerr << "[UndefinedTensor]" << '\n';
   }

aten/src/ATen/core/Vitals.cpp

@@ -9,8 +9,8 @@ APIVitals VitalsAPI;
 
 std::ostream& operator<<(std::ostream& os, TorchVital const& tv) {
   for (const auto& m : tv.attrs) {
-    os << "[TORCH_VITAL] " << tv.name << "." << m.first << "\t\t "
-       << m.second.value << "\n";
+    os << "[TORCH_VITAL] " << tv.name << '.' << m.first << "\t\t "
+       << m.second.value << '\n';
   }
   return os;
 }