MC: Remove the copy of MCSchedModel in MCSubtargetInfo

`MCSchedModel` is large.  Make `MCSchedModel::GetDefaultSchedModel()`
return by-reference instead of by-value, so we can store a pointer in
`MCSubtargetInfo::CPUSchedModel` instead of a copy.

Note: since `MCSchedModel` is POD, this doesn't create a static
constructor.

llvm-svn: 241947

3 files changed, 39 insertions, 6 deletions

diff --git a/llvm/lib/MC/CMakeLists.txt b/llvm/lib/MC/CMakeLists.txt
index 13c5ca9561d..6554d6a9e60 100644
--- a/llvm/lib/MC/CMakeLists.txt
+++ b/llvm/lib/MC/CMakeLists.txt
@@ -28,6 +28,7 @@ add_llvm_library(LLVMMC
   MCObjectStreamer.cpp
   MCObjectWriter.cpp
   MCRegisterInfo.cpp
+  MCSchedule.cpp
   MCSection.cpp
   MCSectionCOFF.cpp
   MCSectionELF.cpp
diff --git a/llvm/lib/MC/MCSchedule.cpp b/llvm/lib/MC/MCSchedule.cpp
new file mode 100644
index 00000000000..0aa20f9fe22
--- /dev/null
+++ b/llvm/lib/MC/MCSchedule.cpp
@@ -0,0 +1,33 @@
+//===- MCSchedule.cpp - Scheduling ------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the default scheduling model.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/MCSchedule.h"
+
+using namespace llvm;
+
+static_assert(std::is_pod<MCSchedModel>::value,
+              "We shouldn't have a static constructor here");
+const MCSchedModel MCSchedModel::Default = {DefaultIssueWidth,
+                                            DefaultMicroOpBufferSize,
+                                            DefaultLoopMicroOpBufferSize,
+                                            DefaultLoadLatency,
+                                            DefaultHighLatency,
+                                            DefaultMispredictPenalty,
+                                            false,
+                                            true,
+                                            0,
+                                            nullptr,
+                                            nullptr,
+                                            0,
+                                            0,
+                                            nullptr};
diff --git a/llvm/lib/MC/MCSubtargetInfo.cpp b/llvm/lib/MC/MCSubtargetInfo.cpp
index ece775c4f08..414512a3a2c 100644
--- a/llvm/lib/MC/MCSubtargetInfo.cpp
+++ b/llvm/lib/MC/MCSubtargetInfo.cpp
@@ -29,9 +29,9 @@ MCSubtargetInfo::InitMCProcessorInfo(StringRef CPU, StringRef FS) {
 void
 MCSubtargetInfo::InitCPUSchedModel(StringRef CPU) {
   if (!CPU.empty())
-    CPUSchedModel = getSchedModelForCPU(CPU);
+    CPUSchedModel = &getSchedModelForCPU(CPU);
   else
-    CPUSchedModel = MCSchedModel::GetDefaultSchedModel();
+    CPUSchedModel = &MCSchedModel::GetDefaultSchedModel();
 }
 
 void MCSubtargetInfo::InitMCSubtargetInfo(
@@ -82,8 +82,7 @@ FeatureBitset MCSubtargetInfo::ApplyFeatureFlag(StringRef FS) {
   return FeatureBits;
 }
 
-MCSchedModel
-MCSubtargetInfo::getSchedModelForCPU(StringRef CPU) const {
+const MCSchedModel &MCSubtargetInfo::getSchedModelForCPU(StringRef CPU) const {
   assert(ProcSchedModels && "Processor machine model not available!");
 
   unsigned NumProcs = ProcDesc.size();
@@ -116,6 +115,6 @@ MCSubtargetInfo::getInstrItineraryForCPU(StringRef CPU) const {
 
 /// Initialize an InstrItineraryData instance.
 void MCSubtargetInfo::initInstrItins(InstrItineraryData &InstrItins) const {
-  InstrItins =
-    InstrItineraryData(CPUSchedModel, Stages, OperandCycles, ForwardingPaths);
+  InstrItins = InstrItineraryData(getSchedModel(), Stages, OperandCycles,
+                                  ForwardingPaths);
 }