CodeGen: Remove MachineFunctionAnalysis => Enable (Machine)ModulePasses

Re-apply this patch, hopefully I will get away without any warnings
in the constructor now.

This patch removes the MachineFunctionAnalysis. Instead we keep a
map from IR Function to MachineFunction in the MachineModuleInfo.

This allows the insertion of ModulePasses into the codegen pipeline
without breaking it because the MachineFunctionAnalysis gets dropped
before a module pass.

Peak memory should stay unchanged without a ModulePass in the codegen
pipeline: Previously the MachineFunction was freed at the end of a codegen
function pipeline because the MachineFunctionAnalysis was dropped; With
this patch the MachineFunction is freed after the AsmPrinter has
finished.

Differential Revision: http://reviews.llvm.org/D23736

llvm-svn: 279602

Author: MatzeB

llvm/include/llvm/CodeGen/MachineFunctionAnalysis.h

@@ -54,6 +54,7 @@ class BlockAddress;
 class MDNode;
 class MMIAddrLabelMap;
 class MachineBasicBlock;
+class MachineFunctionInitializer;
 class MachineFunction;
 class Module;
 class PointerType;
@@ -107,6 +108,8 @@ class MachineModuleInfoImpl {
 /// schemes and reformated for specific use.
 ///
 class MachineModuleInfo : public ImmutablePass {
+  const TargetMachine &TM;
+
   /// Context - This is the MCContext used for the entire code generator.
   MCContext Context;
 
@@ -184,6 +187,14 @@ class MachineModuleInfo : public ImmutablePass {
 
   EHPersonality PersonalityTypeCache;
 
+  MachineFunctionInitializer *MFInitializer;
+  /// Maps IR Functions to their corresponding MachineFunctions.
+  DenseMap<const Function*, std::unique_ptr<MachineFunction>> MachineFunctions;
+  /// Next unique number available for a MachineFunction.
+  unsigned NextFnNum = 0;
+  const Function *LastRequest = nullptr; ///< Used for shortcut/cache.
+  MachineFunction *LastResult = nullptr; ///< Used for shortcut/cache.
+
 public:
   static char ID; // Pass identification, replacement for typeid
 
@@ -200,7 +211,6 @@ class MachineModuleInfo : public ImmutablePass {
   typedef SmallVector<VariableDbgInfo, 4> VariableDbgInfoMapTy;
   VariableDbgInfoMapTy VariableDbgInfos;
 
-  // Real constructor.
   explicit MachineModuleInfo(const TargetMachine *TM = nullptr);
   ~MachineModuleInfo() override;
 
@@ -218,6 +228,19 @@ class MachineModuleInfo : public ImmutablePass {
   void setModule(const Module *M) { TheModule = M; }
   const Module *getModule() const { return TheModule; }
 
+  void setMachineFunctionInitializer(MachineFunctionInitializer *MFInit) {
+    MFInitializer = MFInit;
+  }
+
+  /// Returns the MachineFunction constructed for the IR function \p F.
+  /// Creates a new MachineFunction and runs the MachineFunctionInitializer
+  /// if none exists yet.
+  MachineFunction &getMachineFunction(const Function &F);
+
+  /// \brief Delete the MachineFunction \p MF and reset the link in the IR
+  /// Function to Machine Function map.
+  void deleteMachineFunctionFor(Function &F);
+
   /// getInfo - Keep track of various per-function pieces of information for
   /// backends that would like to do so.
   ///

llvm/include/llvm/CodeGen/MachineModuleInfo.h

@@ -377,6 +377,9 @@ namespace llvm {
 
   /// This pass performs software pipelining on machine instructions.
   extern char &MachinePipelinerID;
+
+  /// This pass frees the memory occupied by the MachineFunction.
+  FunctionPass *createFreeMachineFunctionPass();
 } // End llvm namespace
 
 /// Target machine pass initializer for passes with dependencies. Use with

llvm/include/llvm/CodeGen/Passes.h

@@ -312,10 +312,6 @@ class LLVMTargetMachine : public TargetMachine {
   bool addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
                          raw_pwrite_stream &OS,
                          bool DisableVerify = true) override;
-
-  /// Add MachineFunctionAnalysis pass to pass manager.
-  void addMachineFunctionAnalysis(PassManagerBase &PM,
-      MachineFunctionInitializer *MFInitializer) const;
 };
 
 } // End llvm namespace

llvm/include/llvm/Target/TargetMachine.h

@@ -59,7 +59,6 @@ add_llvm_library(LLVMCodeGen
   MachineCSE.cpp
   MachineDominanceFrontier.cpp
   MachineDominators.cpp
-  MachineFunctionAnalysis.cpp
   MachineFunction.cpp
   MachineFunctionPass.cpp
   MachineFunctionPrinterPass.cpp

llvm/lib/CodeGen/CMakeLists.txt

@@ -15,7 +15,6 @@
 #include "llvm/Analysis/Passes.h"
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/CodeGen/BasicTTIImpl.h"
-#include "llvm/CodeGen/MachineFunctionAnalysis.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/TargetPassConfig.h"
@@ -102,11 +101,6 @@ TargetIRAnalysis LLVMTargetMachine::getTargetIRAnalysis() {
   });
 }
 
-void LLVMTargetMachine::addMachineFunctionAnalysis(PassManagerBase &PM,
-    MachineFunctionInitializer *MFInitializer) const {
-  PM.add(new MachineFunctionAnalysis(*this, MFInitializer));
-}
-
 /// addPassesToX helper drives creation and initialization of TargetPassConfig.
 static MCContext *
 addPassesToGenerateCode(LLVMTargetMachine *TM, PassManagerBase &PM,
@@ -142,8 +136,8 @@ addPassesToGenerateCode(LLVMTargetMachine *TM, PassManagerBase &PM,
   PassConfig->addISelPrepare();
 
   MachineModuleInfo *MMI = new MachineModuleInfo(TM);
+  MMI->setMachineFunctionInitializer(MFInitializer);
   PM.add(MMI);
-  TM->addMachineFunctionAnalysis(PM, MFInitializer);
 
   // Enable FastISel with -fast, but allow that to be overridden.
   TM->setO0WantsFastISel(EnableFastISelOption != cl::BOU_FALSE);
@@ -265,6 +259,7 @@ bool LLVMTargetMachine::addPassesToEmitFile(
     return true;
 
   PM.add(Printer);
+  PM.add(createFreeMachineFunctionPass());
 
   return false;
 }
@@ -311,6 +306,7 @@ bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
     return true;
 
   PM.add(Printer);
+  PM.add(createFreeMachineFunctionPass());
 
   return false; // success!
 }

llvm/lib/CodeGen/LLVMTargetMachine.cpp

@@ -22,7 +22,7 @@
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
 #include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineFunctionAnalysis.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/StackProtector.h"
 #include "llvm/IR/Dominators.h"
@@ -41,7 +41,9 @@ bool MachineFunctionPass::runOnFunction(Function &F) {
   if (F.hasAvailableExternallyLinkage())
     return false;
 
-  MachineFunction &MF = getAnalysis<MachineFunctionAnalysis>().getMF();
+  MachineModuleInfo &MMI = getAnalysis<MachineModuleInfo>();
+  MachineFunction &MF = MMI.getMachineFunction(F);
+
   MachineFunctionProperties &MFProps = MF.getProperties();
 
 #ifndef NDEBUG
@@ -65,8 +67,8 @@ bool MachineFunctionPass::runOnFunction(Function &F) {
 }
 
 void MachineFunctionPass::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.addRequired<MachineFunctionAnalysis>();
-  AU.addPreserved<MachineFunctionAnalysis>();
+  AU.addRequired<MachineModuleInfo>();
+  AU.addPreserved<MachineModuleInfo>();
 
   // MachineFunctionPass preserves all LLVM IR passes, but there's no
   // high-level way to express this. Instead, just list a bunch of

llvm/lib/CodeGen/MachineFunctionAnalysis.cpp

@@ -13,6 +13,7 @@
 #include "llvm/Analysis/EHPersonalities.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionInitializer.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/IR/Constants.h"
@@ -189,8 +190,9 @@ void MMIAddrLabelMapCallbackPtr::allUsesReplacedWith(Value *V2) {
 //===----------------------------------------------------------------------===//
 
 MachineModuleInfo::MachineModuleInfo(const TargetMachine *TM)
-  : ImmutablePass(ID), Context(TM->getMCAsmInfo(), TM->getMCRegisterInfo(),
-                               TM->getObjFileLowering(), nullptr, false) {
+  : ImmutablePass(ID), TM(*TM),
+    Context(TM->getMCAsmInfo(), TM->getMCRegisterInfo(),
+            TM->getObjFileLowering(), nullptr, false) {
   initializeMachineModuleInfoPass(*PassRegistry::getPassRegistry());
 }
 
@@ -207,7 +209,7 @@ bool MachineModuleInfo::doInitialization(Module &M) {
   DbgInfoAvailable = UsesVAFloatArgument = UsesMorestackAddr = false;
   PersonalityTypeCache = EHPersonality::Unknown;
   AddrLabelSymbols = nullptr;
-  TheModule = nullptr;
+  TheModule = &M;
 
   return false;
 }
@@ -455,3 +457,63 @@ try_next:;
   FilterIds.push_back(0); // terminator
   return FilterID;
 }
+
+MachineFunction &MachineModuleInfo::getMachineFunction(const Function &F) {
+  // Shortcut for the common case where a sequence of MachineFunctionPasses
+  // all query for the same Function.
+  if (LastRequest == &F)
+    return *LastResult;
+
+  auto I = MachineFunctions.insert(
+      std::make_pair(&F, std::unique_ptr<MachineFunction>()));
+  MachineFunction *MF;
+  if (I.second) {
+    // No pre-existing machine function, create a new one.
+    MF = new MachineFunction(&F, TM, NextFnNum++, *this);
+    // Update the set entry.
+    I.first->second.reset(MF);
+
+    if (MFInitializer)
+      if (MFInitializer->initializeMachineFunction(*MF))
+        report_fatal_error("Unable to initialize machine function");
+  } else {
+    MF = I.first->second.get();
+  }
+
+  LastRequest = &F;
+  LastResult = MF;
+  return *MF;
+}
+
+void MachineModuleInfo::deleteMachineFunctionFor(Function &F) {
+  MachineFunctions.erase(&F);
+  LastRequest = nullptr;
+  LastResult = nullptr;
+}
+
+namespace {
+/// This pass frees the MachineFunction object associated with a Function.
+class FreeMachineFunction : public FunctionPass {
+public:
+  static char ID;
+  FreeMachineFunction() : FunctionPass(ID) {}
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<MachineModuleInfo>();
+    AU.addPreserved<MachineModuleInfo>();
+  }
+
+  bool runOnFunction(Function &F) override {
+    MachineModuleInfo &MMI = getAnalysis<MachineModuleInfo>();
+    MMI.deleteMachineFunctionFor(F);
+    return true;
+  }
+};
+char FreeMachineFunction::ID;
+} // end anonymous namespace
+
+namespace llvm {
+FunctionPass *createFreeMachineFunctionPass() {
+  return new FreeMachineFunction();
+}
+} // end namespace llvm

llvm/lib/CodeGen/MachineFunctionPass.cpp

@@ -17,7 +17,6 @@
 #include "llvm/CodeGen/LivePhysRegs.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineFunctionAnalysis.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/Support/CommandLine.h"