Interface to attach maximum function count from PGO to module as module flags.

This provides interface to get and set maximum function counts to Module. This
would allow things like determination of function hotness. The actual setting
of this max function count will have to be done in the frontend.

Differential Revision: http://reviews.llvm.org/D15003

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254647 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/IR/Module.h b/include/llvm/IR/Module.h
index 4e99c42..6cf75e7 100644 (file)
--- a/include/llvm/IR/Module.h
+++ b/include/llvm/IR/Module.h
@@ -15,6 +15,7 @@
 #ifndef LLVM_IR_MODULE_H
 #define LLVM_IR_MODULE_H
 
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/IR/Comdat.h"
 #include "llvm/IR/DataLayout.h"
@@ -639,6 +640,16 @@ public:
   /// \brief Set the PIC level (small or large model)
   void setPICLevel(PICLevel::Level PL);
 /// @}
+
+  /// @name Utility functions for querying and setting PGO counts
+  /// @{
+
+  /// \brief Set maximum function count in PGO mode
+  void setMaximumFunctionCount(uint64_t);
+
+  /// \brief Returns maximum function count in PGO mode
+  Optional<uint64_t> getMaximumFunctionCount();
+  /// @}
 };
 
 /// An raw_ostream inserter for modules.

diff --git a/lib/IR/Module.cpp b/lib/IR/Module.cpp
index 2b9adad..2acd9db 100644 (file)
--- a/lib/IR/Module.cpp
+++ b/lib/IR/Module.cpp
@@ -491,3 +491,15 @@ PICLevel::Level Module::getPICLevel() const {
 void Module::setPICLevel(PICLevel::Level PL) {
   addModuleFlag(ModFlagBehavior::Error, "PIC Level", PL);
 }
+
+void Module::setMaximumFunctionCount(uint64_t Count) {
+  addModuleFlag(ModFlagBehavior::Error, "MaxFunctionCount", Count);
+}
+
+Optional<uint64_t> Module::getMaximumFunctionCount() {
+  auto *Val =
+      cast_or_null<ConstantAsMetadata>(getModuleFlag("MaxFunctionCount"));
+  if (!Val)
+    return None;
+  return cast<ConstantInt>(Val->getValue())->getZExtValue();
+}