Add comments to the diagnostic kinds in Diagnostic.td.

https://reviews.llvm.org/D32371

llvm-svn: 301039

1 files changed, 12 insertions, 0 deletions

diff --git a/clang/include/clang/Basic/Diagnostic.td b/clang/include/clang/Basic/Diagnostic.td
index 39da0060ddb..f25068eca13 100644
--- a/clang/include/clang/Basic/Diagnostic.td
+++ b/clang/include/clang/Basic/Diagnostic.td
@@ -12,6 +12,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+// See the Internals Manual, section The Diagnostics Subsystem for an overview.
+
 // Define the diagnostic severities.
 class Severity<string N> {
   string Name = N;
@@ -100,10 +102,20 @@ class SuppressInSystemHeader {
 class Error<string str>     : Diagnostic<str, CLASS_ERROR, SEV_Error>, SFINAEFailure {
   bit ShowInSystemHeader = 1;
 }
+// Warnings default to on (but can be default-off'd with DefaultIgnore).
+// This is used for warnings about questionable code; warnings about
+// accepted language extensions should use Extension or ExtWarn below instead.
 class Warning<string str>   : Diagnostic<str, CLASS_WARNING, SEV_Warning>;
+// Remarks can be turned on with -R flags and provide commentary, e.g. on
+// optimizer decisions.
 class Remark<string str>    : Diagnostic<str, CLASS_REMARK, SEV_Ignored>;
+// Extensions are warnings about accepted language extensions.
+// Extension warnings are default-off but enabled by -pedantic.
 class Extension<string str> : Diagnostic<str, CLASS_EXTENSION, SEV_Ignored>;
+// ExtWarns are warnings about accepted language extensions.
+// ExtWarn warnings are default-on.
 class ExtWarn<string str>   : Diagnostic<str, CLASS_EXTENSION, SEV_Warning>;
+// Notes can provide supplementary information on errors, warnings, and remarks.
 class Note<string str>      : Diagnostic<str, CLASS_NOTE, SEV_Fatal/*ignored*/>;