From 0f70bc05b34be5792c5e831366639e3f8bd26f19 Mon Sep 17 00:00:00 2001
From: Matt Davis <Matthew.Davis@sony.com>
Date: Thu, 23 Aug 2018 18:42:37 +0000
Subject: [PATCH] [llvm-mca] Set the Selection strategy to Default if nullptr
 is passed.

* Set (not reset) the strategy in Scheduler::setCustomStrategyImpl()

llvm-svn: 340566
---
 llvm/tools/llvm-mca/Scheduler.cpp |  7 ++++++-
 llvm/tools/llvm-mca/Scheduler.h   | 20 ++++++++++++++------
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/llvm/tools/llvm-mca/Scheduler.cpp b/llvm/tools/llvm-mca/Scheduler.cpp
index 4ba48a28b8ed..cc904c84b484 100644
--- a/llvm/tools/llvm-mca/Scheduler.cpp
+++ b/llvm/tools/llvm-mca/Scheduler.cpp
@@ -24,6 +24,11 @@ using namespace llvm;
 
 ResourceStrategy::~ResourceStrategy() = default;
 
+void Scheduler::initializeStrategy(std::unique_ptr<SchedulerStrategy> S) {
+  // Ensure we have a valid (non-null) strategy object.
+  Strategy = S ? std::move(S) : llvm::make_unique<DefaultSchedulerStrategy>();
+}
+
 void DefaultResourceStrategy::skipMask(uint64_t Mask) {
   NextInSequenceMask &= (~Mask);
   if (!NextInSequenceMask) {
@@ -116,7 +121,7 @@ void ResourceManager::setCustomStrategyImpl(std::unique_ptr<ResourceStrategy> S,
   unsigned Index = getResourceStateIndex(ResourceID);
   assert(Index < Resources.size() && "Invalid processor resource index!");
   assert(S && "Unexpected null strategy in input!");
-  Strategies[Index].reset(S.get());
+  Strategies[Index] = std::move(S);
 }
 
 unsigned ResourceManager::resolveResourceMask(uint64_t Mask) const {
diff --git a/llvm/tools/llvm-mca/Scheduler.h b/llvm/tools/llvm-mca/Scheduler.h
index 37ebdb453e23..ed138fd71804 100644
--- a/llvm/tools/llvm-mca/Scheduler.h
+++ b/llvm/tools/llvm-mca/Scheduler.h
@@ -430,6 +430,11 @@ class Scheduler : public HardwareUnit {
   std::vector<InstRef> ReadySet;
   std::vector<InstRef> IssuedSet;
 
+  /// Verify the given selection strategy and set the Strategy member
+  /// accordingly.  If no strategy is provided, the DefaultSchedulerStrategy is
+  /// used.
+  void initializeStrategy(std::unique_ptr<SchedulerStrategy> S);
+
   /// Issue an instruction without updating the ready queue.
   void issueInstructionImpl(
       InstRef &IR,
@@ -446,16 +451,19 @@ class Scheduler : public HardwareUnit {
 
 public:
   Scheduler(const llvm::MCSchedModel &Model, LSUnit *Lsu)
-      : LSU(Lsu), Strategy(llvm::make_unique<DefaultSchedulerStrategy>()),
-        Resources(llvm::make_unique<ResourceManager>(Model)) {}
+      : LSU(Lsu), Resources(llvm::make_unique<ResourceManager>(Model)) {
+    initializeStrategy(nullptr);
+  }
   Scheduler(const llvm::MCSchedModel &Model, LSUnit *Lsu,
             std::unique_ptr<SchedulerStrategy> SelectStrategy)
-      : LSU(Lsu), Strategy(std::move(SelectStrategy)),
-        Resources(llvm::make_unique<ResourceManager>(Model)) {}
+      : LSU(Lsu), Resources(llvm::make_unique<ResourceManager>(Model)) {
+    initializeStrategy(std::move(SelectStrategy));
+  }
   Scheduler(std::unique_ptr<ResourceManager> RM, LSUnit *Lsu,
             std::unique_ptr<SchedulerStrategy> SelectStrategy)
-      : LSU(Lsu), Strategy(std::move(SelectStrategy)),
-        Resources(std::move(RM)) {}
+      : LSU(Lsu), Resources(std::move(RM)) {
+    initializeStrategy(std::move(SelectStrategy));
+  }
 
   // Stalls generated by the scheduler.
   enum Status {