[PATCH] Add support for optimization reports.

[Richard Smith]

================
Comment at: lib/Frontend/CompilerInvocation.cpp:526
@@ +525,3 @@
+    std::string RegexError;
+    Opts.OptimizationRemarkPattern = new llvm::Regex(Val);
+    if (!Opts.OptimizationRemarkPattern->isValid(RegexError)) {
----------------
Diego Novillo wrote:
> Richard Smith wrote:
> > It looks like this is leaked. Maybe use an `llvm::Optional<llvm::Regex>` instead?
> I tried but llvm::Regex has an explicitly deleted constructor. I'm not sure how to deal with that, so I ended up using regular pointer semantics.
`llvm::Optional` shouldn't call the `llvm::Regex` default constructor.

================
Comment at: lib/CodeGen/CodeGenAction.cpp:433
@@ +432,3 @@
+      return;
+    ComputeDiagRemarkID(Severity, backend_optimization_remark, DiagID);
+    break;
----------------
It looks like we get here (and potentially use the error/warning forms of the remark diagnostic) if the diagnostic severity isn't `DS_Remark`. I don't think this is what we want -- maybe the severity check in `OptimizationRemarkHandler` should be an assert?

================
Comment at: include/clang/Basic/DiagnosticFrontendKinds.td:40-42
@@ +39,5 @@
+def note_fe_backend_optimization_remark : Note<"%0">, CatBackend;
+def note_fe_backend_optimization_remark_missing_loc : Note<"optimization "
+  "remarks cannot show source location information (use -gline-tables-only "
+  "-gcolumn-info to enable it)">;
+
----------------
Maybe better phrased as:

  "use -gline-tables-only -gcolumn-info to track source location information for this optimization remark"


http://reviews.llvm.org/D3226