[clang-format] ensure clang-format command-line argument sets up the default left/right qualifier ordering

[MyDeveloperDay]

Summary

When specifying the alignment direction on the command line ensure we set up the default ordering.
Fix spelling mistakes in the command-line argument

[MyDeveloperDay]

This is to support D69764: [clang-format] Add Left/Right Const fixer capability

[MyDeveloperDay]

Allow passing of desired qualifier order on the command line

clang-format --qualifier-alignment="const static type volatile" test_file.cpp

[MyDeveloperDay]

Rename the ConstAlignment variable

[HazardyKnusperkeks]

Just fix what clang-format tells you to. :)

clang/tools/clang-format/ClangFormat.cpp

 
 static cl::opt<bool> SortIncludes(
     "sort-includes",
     cl::desc("If set, overrides the include sorting behavior determined by the "
              "SortIncludes style flag"),
     cl::cat(ClangFormatCategory));
 
 static cl::opt<std::string> QualifierAlignment(
-    "qualifier-aligment",
+    "qualifier-alignment",
     cl::desc(
-        "If set, overrides the cvqualifier style behavior determined by the "
+        "If set, overrides the qualifier alignment style determined by the "
         "QualifierAlignment style flag"),
     cl::init(""), cl::cat(ClangFormatCategory));
 
 static cl::opt<bool>
     Verbose("verbose", cl::desc("If set, shows the list of processed files"),
             cl::cat(ClangFormatCategory));
 
 // Use --dry-run to match other LLVM tools when you mean do it but don't
static bool format(StringRef FileName) {
   llvm::Expected<FormatStyle> FormatStyle =
       getStyle(Style, AssumedFileName, FallbackStyle, Code->getBuffer(),
                nullptr, WNoErrorList.isSet(WNoError::Unknown));
   if (!FormatStyle) {
     llvm::errs() << llvm::toString(FormatStyle.takeError()) << "\n";
     return true;
   }
 
-  StringRef ConstAlignment = QualifierAlignment;
+  StringRef QualifierAlignmentOrder = QualifierAlignment;
 
   FormatStyle->QualifierAlignment =
-      StringSwitch<FormatStyle::QualifierAlignmentStyle>(ConstAlignment.lower())
+      StringSwitch<FormatStyle::QualifierAlignmentStyle>(
+          QualifierAlignmentOrder.lower())
           .Case("right", FormatStyle::QAS_Right)
           .Case("left", FormatStyle::QAS_Left)
           .Default(FormatStyle->QualifierAlignment);
 
+  if (FormatStyle->QualifierAlignment == FormatStyle::QAS_Left)
+    FormatStyle->QualifierOrder = {"const", "volatile", "type"};
+  else if (FormatStyle->QualifierAlignment == FormatStyle::QAS_Right)
+    FormatStyle->QualifierOrder = {"type", "const", "volatile"};
+  else if (QualifierAlignmentOrder.contains("type")) {
+    FormatStyle->QualifierAlignment = FormatStyle::QAS_Custom;
+    SmallVector<StringRef> Qualifiers;
+    QualifierAlignmentOrder.split(Qualifiers, " ", /*MaxSplit=*/-1,
+                                  /*KeepEmpty=*/false);
+    FormatStyle->QualifierOrder = {Qualifiers.begin(), Qualifiers.end()};
+  }
+
   if (SortIncludes.getNumOccurrences() != 0) {
     if (SortIncludes)
       FormatStyle->SortIncludes = FormatStyle::SI_CaseSensitive;
     else
       FormatStyle->SortIncludes = FormatStyle::SI_Never;
   }
   unsigned CursorPosition = Cursor;
   Replacements Replaces = sortIncludes(*FormatStyle, Code->getBuffer(), Ranges,