From 302b69c9406b1c690db2e8faaf0a2211dfd46879 Mon Sep 17 00:00:00 2001
From: Dehao Chen <dehao@google.com>
Date: Tue, 18 Oct 2016 20:42:47 +0000
Subject: Use profile info to set function section prefix to group hot/cold
 functions.

Summary:
The original implementation is in r261607, which was reverted in r269726 to accomendate the ProfileSummaryInfo analysis pass. The new implementation:
1. add a new metadata for function section prefix
2. query against ProfileSummaryInfo in CGP to set the correct section prefix for each function
3. output the section prefix set by CGP

Reviewers: davidxl, eraman

Subscribers: vsk, llvm-commits

Differential Revision: https://reviews.llvm.org/D24989

llvm-svn: 284533
---
 llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

(limited to 'llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp')

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index edaa778a605..91cee337c98 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -296,8 +296,12 @@ selectELFSectionForGlobal(MCContext &Ctx, const GlobalValue *GV,
   } else {
     Name = getSectionPrefixForGlobal(Kind);
   }
-  // FIXME: Extend the section prefix to include hotness catagories such as .hot
-  //  or .unlikely for functions.
+
+  if (const Function *F = dyn_cast<Function>(GV)) {
+    const auto &OptionalPrefix = F->getSectionPrefix();
+    if (OptionalPrefix)
+      Name += *OptionalPrefix;
+  }
 
   if (EmitUniqueSection && UniqueSectionNames) {
     Name.push_back('.');
-- 
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