1 files changed, 68 insertions, 0 deletions
diff --git a/lib/Analysis/LazyBlockFrequencyInfo.cpp b/lib/Analysis/LazyBlockFrequencyInfo.cpp
new file mode 100644
index 0000000000000..7debfde87d2a3
--- /dev/null
+++ b/lib/Analysis/LazyBlockFrequencyInfo.cpp
@@ -0,0 +1,68 @@
+//===- LazyBlockFrequencyInfo.cpp - Lazy Block Frequency Analysis ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is an alternative analysis pass to BlockFrequencyInfoWrapperPass.  The
+// difference is that with this pass the block frequencies are not computed when
+// the analysis pass is executed but rather when the BFI results is explicitly
+// requested by the analysis client.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/LazyBlockFrequencyInfo.h"
+#include "llvm/Analysis/BranchProbabilityInfo.h"
+#include "llvm/Analysis/LoopInfo.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "lazy-block-freq"
+
+INITIALIZE_PASS_BEGIN(LazyBlockFrequencyInfoPass, DEBUG_TYPE,
+                      "Lazy Block Frequency Analysis", true, true)
+INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
+INITIALIZE_PASS_END(LazyBlockFrequencyInfoPass, DEBUG_TYPE,
+                    "Lazy Block Frequency Analysis", true, true)
+
+char LazyBlockFrequencyInfoPass::ID = 0;
+
+LazyBlockFrequencyInfoPass::LazyBlockFrequencyInfoPass() : FunctionPass(ID) {
+  initializeLazyBlockFrequencyInfoPassPass(*PassRegistry::getPassRegistry());
+}
+
+void LazyBlockFrequencyInfoPass::print(raw_ostream &OS, const Module *) const {
+  LBFI.getCalculated().print(OS);
+}
+
+void LazyBlockFrequencyInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<BranchProbabilityInfoWrapperPass>();
+  AU.addRequired<LoopInfoWrapperPass>();
+  AU.setPreservesAll();
+}
+
+void LazyBlockFrequencyInfoPass::releaseMemory() { LBFI.releaseMemory(); }
+
+bool LazyBlockFrequencyInfoPass::runOnFunction(Function &F) {
+  BranchProbabilityInfo &BPI =
+      getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
+  LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+  LBFI.setAnalysis(&F, &BPI, &LI);
+  return false;
+}
+
+void LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AnalysisUsage &AU) {
+  AU.addRequired<BranchProbabilityInfoWrapperPass>();
+  AU.addRequired<LazyBlockFrequencyInfoPass>();
+  AU.addRequired<LoopInfoWrapperPass>();
+}
+
+void llvm::initializeLazyBFIPassPass(PassRegistry &Registry) {
+  INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass);
+  INITIALIZE_PASS_DEPENDENCY(LazyBlockFrequencyInfoPass);
+  INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
+}