[ORE] Add diagnostics hotness threshold

Summary:
Add an option to prevent diagnostics that do not meet a minimum hotness
threshold from being output. When generating optimization remarks for
large codebases with a ton of cold code paths, this option can be used
to limit the optimization remark output at a reasonable size. Discussion of
this change can be read here:
http://lists.llvm.org/pipermail/llvm-dev/2017-June/114377.html

Reviewers: anemet, davidxl, hfinkel

Reviewed By: anemet

Subscribers: qcolombet, javed.absar, fhahn, eraman, llvm-commits

Differential Revision: https://reviews.llvm.org/D34867

llvm-svn: 306912

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/include/llvm/IR/LLVMContext.h b/llvm/include/llvm/IR/LLVMContext.h
index c8ff90e3b08..b27abad618c 100644
--- a/llvm/include/llvm/IR/LLVMContext.h
+++ b/llvm/include/llvm/IR/LLVMContext.h
@@ -193,6 +193,15 @@ public:
   /// diagnostics.
   void setDiagnosticsHotnessRequested(bool Requested);
 
+  /// \brief Return the minimum hotness value a diagnostic would need in order
+  /// to be included in optimization diagnostics. If there is no minimum, this
+  /// returns None.
+  uint64_t getDiagnosticsHotnessThreshold() const;
+
+  /// \brief Set the minimum hotness value a diagnostic needs in order to be
+  /// included in optimization diagnostics.
+  void setDiagnosticsHotnessThreshold(uint64_t Threshold);
+
   /// \brief Return the YAML file used by the backend to save optimization
   /// diagnostics.  If null, diagnostics are not saved in a file but only
   /// emitted via the diagnostic handler.