[Profile] Add off-by-default -Wprofile-instr-missing warning

Clang warns that a profile is out-of-date if it can't find a profile
record for any function in a TU. This warning became noisy after llvm
started allowing dead-stripping of instrumented functions.

To fix this, this patch changes the existing profile out-of-date warning
(-Wprofile-instr-out-of-date) so that it only complains about mismatched
data. Further, it introduces a new, off-by-default warning about missing
function data (-Wprofile-instr-missing).

Differential Revision: https://reviews.llvm.org/D28867

llvm-svn: 301570

1 files changed, 7 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 25d32f19d0e..27dfb069e2e 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -369,9 +369,13 @@ void InstrProfStats::reportDiagnostics(DiagnosticsEngine &Diags,
     if (MainFile.empty())
       MainFile = "<stdin>";
     Diags.Report(diag::warn_profile_data_unprofiled) << MainFile;
-  } else
-    Diags.Report(diag::warn_profile_data_out_of_date) << Visited << Missing
-                                                      << Mismatched;
+  } else {
+    if (Mismatched > 0)
+      Diags.Report(diag::warn_profile_data_out_of_date) << Visited << Mismatched;
+
+    if (Missing > 0)
+      Diags.Report(diag::warn_profile_data_missing) << Visited << Missing;
+  }
 }
 
 void CodeGenModule::Release() {