Add new pass LazyMachineBlockFrequencyInfo

And use it in MachineOptimizationRemarkEmitter.  A test will follow on top of
Justin's changes to enable MachineORE in AsmPrinter.

The approach is similar to the IR-level pass.  It's a bit simpler because BPI
is immutable at the Machine level so we don't need to make that lazy.

Because of this, a new function mapping is introduced (BPIPassTrait::getBPI).
This function extracts BPI from the pass.  In case of the lazy pass, this is
when the calculation of the BFI occurs.  For Machine-level, this is the
identity function.

Differential Revision: https://reviews.llvm.org/D29836

llvm-svn: 295072

1 files changed, 74 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/LazyMachineBlockFrequencyInfo.cpp b/llvm/lib/CodeGen/LazyMachineBlockFrequencyInfo.cpp
new file mode 100644
index 00000000000..34611f8064d
--- /dev/null
+++ b/llvm/lib/CodeGen/LazyMachineBlockFrequencyInfo.cpp
@@ -0,0 +1,74 @@
+///===- LazyMachineBlockFrequencyInfo.cpp - Lazy Machine Block Frequency --===//
+///
+///                     The LLVM Compiler Infrastructure
+///
+/// This file is distributed under the University of Illinois Open Source
+/// License. See LICENSE.TXT for details.
+///
+///===---------------------------------------------------------------------===//
+/// \file
+/// This is an alternative analysis pass to MachineBlockFrequencyInfo.  The
+/// difference is that with this pass the block frequencies are not computed
+/// when the analysis pass is executed but rather when the BFI result is
+/// explicitly requested by the analysis client.
+///
+///===---------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/LazyMachineBlockFrequencyInfo.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "lazy-machine-block-freq"
+
+INITIALIZE_PASS_BEGIN(LazyMachineBlockFrequencyInfoPass, DEBUG_TYPE,
+                      "Lazy Machine Block Frequency Analysis", true, true)
+INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
+INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
+INITIALIZE_PASS_END(LazyMachineBlockFrequencyInfoPass, DEBUG_TYPE,
+                    "Lazy Machine Block Frequency Analysis", true, true)
+
+char LazyMachineBlockFrequencyInfoPass::ID = 0;
+
+LazyMachineBlockFrequencyInfoPass::LazyMachineBlockFrequencyInfoPass()
+    : MachineFunctionPass(ID) {
+  initializeLazyMachineBlockFrequencyInfoPassPass(
+      *PassRegistry::getPassRegistry());
+}
+
+void LazyMachineBlockFrequencyInfoPass::print(raw_ostream &OS,
+                                              const Module *M) const {
+  LMBFI.getCalculated().print(OS, M);
+}
+
+void LazyMachineBlockFrequencyInfoPass::getAnalysisUsage(
+    AnalysisUsage &AU) const {
+  AU.addRequired<MachineBranchProbabilityInfo>();
+  AU.addRequired<MachineLoopInfo>();
+  AU.setPreservesAll();
+  MachineFunctionPass::getAnalysisUsage(AU);
+}
+
+void LazyMachineBlockFrequencyInfoPass::releaseMemory() {
+  LMBFI.releaseMemory();
+}
+
+bool LazyMachineBlockFrequencyInfoPass::runOnMachineFunction(
+    MachineFunction &MF) {
+  auto &BPIPass = getAnalysis<MachineBranchProbabilityInfo>();
+  auto &LI = getAnalysis<MachineLoopInfo>();
+  LMBFI.setAnalysis(&MF, &BPIPass, &LI);
+  return false;
+}
+
+void LazyMachineBlockFrequencyInfoPass::getLazyMachineBFIAnalysisUsage(
+    AnalysisUsage &AU) {
+  AU.addRequired<LazyMachineBlockFrequencyInfoPass>();
+  AU.addRequired<MachineBranchProbabilityInfo>();
+  AU.addRequired<MachineLoopInfo>();
+}
+
+void llvm::initializeLazyMachineBFIPassPass(PassRegistry &Registry) {
+  INITIALIZE_PASS_DEPENDENCY(LazyMachineBlockFrequencyInfoPass);
+  INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo);
+  INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo);
+}