Add prefix based function layout when profile is available.

Summary: If a function is hot, put it in text.hot section.

Reviewers: davidxl

Subscribers: eraman, mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D17460

llvm-svn: 261582

1 files changed, 21 insertions, 0 deletions

diff --git a/llvm/lib/ProfileData/ProfileSummary.cpp b/llvm/lib/ProfileData/ProfileSummary.cpp
index 0e2c43e5e91..0363fbfe42d 100644
--- a/llvm/lib/ProfileData/ProfileSummary.cpp
+++ b/llvm/lib/ProfileData/ProfileSummary.cpp
@@ -11,6 +11,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/IR/Attributes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Module.h"
 #include "llvm/ProfileData/InstrProf.h"
 #include "llvm/ProfileData/ProfileCommon.h"
 #include "llvm/ProfileData/SampleProf.h"
@@ -75,6 +78,24 @@ void ProfileSummary::computeDetailedSummary() {
   }
 }
 
+// Returns true if the function is a hot function.
+bool ProfileSummary::isFunctionHot(const Function *F) {
+  // FIXME: update when summary data is stored in module's metadata.
+  return false;
+}
+
+// Returns true if the function is a cold function.
+bool ProfileSummary::isFunctionUnlikely(const Function *F) {
+  if (F->hasFnAttribute(Attribute::Cold)) {
+    return true;
+  }
+  if (!F->getEntryCount()) {
+    return false;
+  }
+  // FIXME: update when summary data is stored in module's metadata.
+  return (*F->getEntryCount()) == 0;
+}
+
 InstrProfSummary::InstrProfSummary(const IndexedInstrProf::Summary &S)
     : ProfileSummary(), MaxInternalBlockCount(S.get(
                             IndexedInstrProf::Summary::MaxInternalBlockCount)),