[PATCH] [clang-tidy] Implement the include order checker for LLVM.

[Alexander Kornienko]

Looks good provided the comments are addressed.

================
Comment at: clang-tidy/llvm/IncludeOrderCheck.cpp:71
@@ +70,3 @@
+/// \brief Find the offset of the next end of a line.
+static int findEndOfLine(const char *Text) {
+  return std::strcspn(Text, "\n");
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Now that it is just one call, it's not particularly useful to have a separate function. Maybe inline it?

================
Comment at: clang-tidy/llvm/IncludeOrderCheck.cpp:103
@@ +102,3 @@
+  for (unsigned I = 1, E = IncludeDirectives.size(); I != E; ++I)
+    if (SM.getPresumedLineNumber(IncludeDirectives[I].Loc) !=
+        SM.getPresumedLineNumber(IncludeDirectives[I - 1].Loc) + 1)
----------------
It probably doesn't matter much, but I don't think we need presumed locations here. Considering #line directives doesn't make much sense in this context.

================
Comment at: clang-tidy/llvm/IncludeOrderCheck.cpp:142
@@ +141,3 @@
+    auto D =
+        Check.diag(IncludeDirectives[I].Loc, "#includes not sorted properly");
+
----------------
Maybe "#includes are not sorted properly"?

http://reviews.llvm.org/D4741