remove the StructRetPromotion pass. It is unused, not maintained and

has some bugs.  If this is interesting functionality, it should be 
reimplemented in the argpromotion pass.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129314 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 0 insertions, 359 deletions

diff --git a/lib/Transforms/IPO/CMakeLists.txt b/lib/Transforms/IPO/CMakeLists.txt
index efdeec5640..179b150c14 100644
--- a/lib/Transforms/IPO/CMakeLists.txt
+++ b/lib/Transforms/IPO/CMakeLists.txt
@@ -20,5 +20,4 @@ add_llvm_library(LLVMipo
   PruneEH.cpp
   StripDeadPrototypes.cpp
   StripSymbols.cpp
-  StructRetPromotion.cpp
   )
diff --git a/lib/Transforms/IPO/IPO.cpp b/lib/Transforms/IPO/IPO.cpp
index fbe90ce675..21dcb519d9 100644
--- a/lib/Transforms/IPO/IPO.cpp
+++ b/lib/Transforms/IPO/IPO.cpp
@@ -45,7 +45,6 @@ void llvm::initializeIPO(PassRegistry &Registry) {
   initializeStripDebugDeclarePass(Registry);
   initializeStripDeadDebugInfoPass(Registry);
   initializeStripNonDebugSymbolsPass(Registry);
-  initializeSRETPromotionPass(Registry);
 }
 
 void LLVMInitializeIPO(LLVMPassRegistryRef R) {
diff --git a/lib/Transforms/IPO/StructRetPromotion.cpp b/lib/Transforms/IPO/StructRetPromotion.cpp
deleted file mode 100644
index 584deacaff..0000000000
--- a/lib/Transforms/IPO/StructRetPromotion.cpp
+++ /dev/null
@@ -1,357 +0,0 @@
-//===-- StructRetPromotion.cpp - Promote sret arguments -------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass finds functions that return a struct (using a pointer to the struct
-// as the first argument of the function, marked with the 'sret' attribute) and
-// replaces them with a new function that simply returns each of the elements of
-// that struct (using multiple return values).
-//
-// This pass works under a number of conditions:
-//  1. The returned struct must not contain other structs
-//  2. The returned struct must only be used to load values from
-//  3. The placeholder struct passed in is the result of an alloca
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "sretpromotion"
-#include "llvm/Transforms/IPO.h"
-#include "llvm/Constants.h"
-#include "llvm/DerivedTypes.h"
-#include "llvm/LLVMContext.h"
-#include "llvm/Module.h"
-#include "llvm/CallGraphSCCPass.h"
-#include "llvm/Instructions.h"
-#include "llvm/Analysis/CallGraph.h"
-#include "llvm/Support/CallSite.h"
-#include "llvm/Support/CFG.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Support/raw_ostream.h"
-using namespace llvm;
-
-STATISTIC(NumRejectedSRETUses , "Number of sret rejected due to unexpected uses");
-STATISTIC(NumSRET , "Number of sret promoted");
-namespace {
-  /// SRETPromotion - This pass removes sret parameter and updates
-  /// function to use multiple return value.
-  ///
-  struct SRETPromotion : public CallGraphSCCPass {
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      CallGraphSCCPass::getAnalysisUsage(AU);
-    }
-
-    virtual bool runOnSCC(CallGraphSCC &SCC);
-    static char ID; // Pass identification, replacement for typeid
-    SRETPromotion() : CallGraphSCCPass(ID) {
-      initializeSRETPromotionPass(*PassRegistry::getPassRegistry());
-    }
-
-  private:
-    CallGraphNode *PromoteReturn(CallGraphNode *CGN);
-    bool isSafeToUpdateAllCallers(Function *F);
-    Function *cloneFunctionBody(Function *F, const StructType *STy);
-    CallGraphNode *updateCallSites(Function *F, Function *NF);
-  };
-}
-
-char SRETPromotion::ID = 0;
-INITIALIZE_PASS_BEGIN(SRETPromotion, "sretpromotion",
-                "Promote sret arguments to multiple ret values", false, false)
-INITIALIZE_AG_DEPENDENCY(CallGraph)
-INITIALIZE_PASS_END(SRETPromotion, "sretpromotion",
-                "Promote sret arguments to multiple ret values", false, false)
-
-Pass *llvm::createStructRetPromotionPass() {
-  return new SRETPromotion();
-}
-
-bool SRETPromotion::runOnSCC(CallGraphSCC &SCC) {
-  bool Changed = false;
-
-  for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I)
-    if (CallGraphNode *NewNode = PromoteReturn(*I)) {
-      SCC.ReplaceNode(*I, NewNode);
-      Changed = true;
-    }
-
-  return Changed;
-}
-
-/// PromoteReturn - This method promotes function that uses StructRet paramater 
-/// into a function that uses multiple return values.
-CallGraphNode *SRETPromotion::PromoteReturn(CallGraphNode *CGN) {
-  Function *F = CGN->getFunction();
-
-  if (!F || F->isDeclaration() || !F->hasLocalLinkage())
-    return 0;
-
-  // Make sure that function returns struct.
-  if (F->arg_size() == 0 || !F->hasStructRetAttr() || F->doesNotReturn())
-    return 0;
-
-  DEBUG(dbgs() << "SretPromotion: Looking at sret function " 
-        << F->getName() << "\n");
-
-  assert(F->getReturnType()->isVoidTy() && "Invalid function return type");
-  Function::arg_iterator AI = F->arg_begin();
-  const llvm::PointerType *FArgType = dyn_cast<PointerType>(AI->getType());
-  assert(FArgType && "Invalid sret parameter type");
-  const llvm::StructType *STy = 
-    dyn_cast<StructType>(FArgType->getElementType());
-  assert(STy && "Invalid sret parameter element type");
-
-  // Check if it is ok to perform this promotion.
-  if (isSafeToUpdateAllCallers(F) == false) {
-    DEBUG(dbgs() << "SretPromotion: Not all callers can be updated\n");
-    ++NumRejectedSRETUses;
-    return 0;
-  }
-
-  DEBUG(dbgs() << "SretPromotion: sret argument will be promoted\n");
-  ++NumSRET;
-  // [1] Replace use of sret parameter 
-  AllocaInst *TheAlloca = new AllocaInst(STy, NULL, "mrv", 
-                                         F->getEntryBlock().begin());
-  Value *NFirstArg = F->arg_begin();
-  NFirstArg->replaceAllUsesWith(TheAlloca);
-
-  // [2] Find and replace ret instructions
-  for (Function::iterator FI = F->begin(), FE = F->end();  FI != FE; ++FI) 
-    for(BasicBlock::iterator BI = FI->begin(), BE = FI->end(); BI != BE; ) {
-      Instruction *I = BI;
-      ++BI;
-      if (isa<ReturnInst>(I)) {
-        Value *NV = new LoadInst(TheAlloca, "mrv.ld", I);
-        ReturnInst *NR = ReturnInst::Create(F->getContext(), NV, I);
-        I->replaceAllUsesWith(NR);
-        I->eraseFromParent();
-      }
-    }
-
-  // [3] Create the new function body and insert it into the module.
-  Function *NF = cloneFunctionBody(F, STy);
-
-  // [4] Update all call sites to use new function
-  CallGraphNode *NF_CFN = updateCallSites(F, NF);
-
-  CallGraph &CG = getAnalysis<CallGraph>();
-  NF_CFN->stealCalledFunctionsFrom(CG[F]);
-
-  delete CG.removeFunctionFromModule(F);
-  return NF_CFN;
-}
-
-// Check if it is ok to perform this promotion.
-bool SRETPromotion::isSafeToUpdateAllCallers(Function *F) {
-
-  if (F->use_empty())
-    // No users. OK to modify signature.
-    return true;
-
-  for (Value::use_iterator FnUseI = F->use_begin(), FnUseE = F->use_end();
-       FnUseI != FnUseE; ++FnUseI) {
-    // The function is passed in as an argument to (possibly) another function,
-    // we can't change it!
-    CallSite CS(*FnUseI);
-    Instruction *Call = CS.getInstruction();
-    // The function is used by something else than a call or invoke instruction,
-    // we can't change it!
-    if (!Call || !CS.isCallee(FnUseI))
-      return false;
-    CallSite::arg_iterator AI = CS.arg_begin();
-    Value *FirstArg = *AI;
-
-    if (!isa<AllocaInst>(FirstArg))
-      return false;
-
-    // Check FirstArg's users.
-    for (Value::use_iterator ArgI = FirstArg->use_begin(), 
-           ArgE = FirstArg->use_end(); ArgI != ArgE; ++ArgI) {
-      User *U = *ArgI;
-      // If FirstArg user is a CallInst that does not correspond to current
-      // call site then this function F is not suitable for sret promotion.
-      if (CallInst *CI = dyn_cast<CallInst>(U)) {
-        if (CI != Call)
-          return false;
-      }
-      // If FirstArg user is a GEP whose all users are not LoadInst then
-      // this function F is not suitable for sret promotion.
-      else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(U)) {
-        // TODO : Use dom info and insert PHINodes to collect get results
-        // from multiple call sites for this GEP.
-        if (GEP->getParent() != Call->getParent())
-          return false;
-        for (Value::use_iterator GEPI = GEP->use_begin(), GEPE = GEP->use_end();
-             GEPI != GEPE; ++GEPI) 
-          if (!isa<LoadInst>(*GEPI))
-            return false;
-      } 
-      // Any other FirstArg users make this function unsuitable for sret 
-      // promotion.
-      else
-        return false;
-    }
-  }
-
-  return true;
-}
-
-/// cloneFunctionBody - Create a new function based on F and
-/// insert it into module. Remove first argument. Use STy as
-/// the return type for new function.
-Function *SRETPromotion::cloneFunctionBody(Function *F, 
-                                           const StructType *STy) {
-
-  const FunctionType *FTy = F->getFunctionType();
-  std::vector<const Type*> Params;
-
-  // Attributes - Keep track of the parameter attributes for the arguments.
-  SmallVector<AttributeWithIndex, 8> AttributesVec;
-  const AttrListPtr &PAL = F->getAttributes();
-
-  // Add any return attributes.
-  if (Attributes attrs = PAL.getRetAttributes())
-    AttributesVec.push_back(AttributeWithIndex::get(0, attrs));
-
-  // Skip first argument.
-  Function::arg_iterator I = F->arg_begin(), E = F->arg_end();
-  ++I;
-  // 0th parameter attribute is reserved for return type.
-  // 1th parameter attribute is for first 1st sret argument.
-  unsigned ParamIndex = 2; 
-  while (I != E) {
-    Params.push_back(I->getType());
-    if (Attributes Attrs = PAL.getParamAttributes(ParamIndex))
-      AttributesVec.push_back(AttributeWithIndex::get(ParamIndex - 1, Attrs));
-    ++I;
-    ++ParamIndex;
-  }
-
-  // Add any fn attributes.
-  if (Attributes attrs = PAL.getFnAttributes())
-    AttributesVec.push_back(AttributeWithIndex::get(~0, attrs));
-
-
-  FunctionType *NFTy = FunctionType::get(STy, Params, FTy->isVarArg());
-  Function *NF = Function::Create(NFTy, F->getLinkage());
-  NF->takeName(F);
-  NF->copyAttributesFrom(F);
-  NF->setAttributes(AttrListPtr::get(AttributesVec.begin(), AttributesVec.end()));
-  F->getParent()->getFunctionList().insert(F, NF);
-  NF->getBasicBlockList().splice(NF->begin(), F->getBasicBlockList());
-
-  // Replace arguments
-  I = F->arg_begin();
-  E = F->arg_end();
-  Function::arg_iterator NI = NF->arg_begin();
-  ++I;
-  while (I != E) {
-    I->replaceAllUsesWith(NI);
-    NI->takeName(I);
-    ++I;
-    ++NI;
-  }
-
-  return NF;
-}
-
-/// updateCallSites - Update all sites that call F to use NF.
-CallGraphNode *SRETPromotion::updateCallSites(Function *F, Function *NF) {
-  CallGraph &CG = getAnalysis<CallGraph>();
-  SmallVector<Value*, 16> Args;
-
-  // Attributes - Keep track of the parameter attributes for the arguments.
-  SmallVector<AttributeWithIndex, 8> ArgAttrsVec;
-
-  // Get a new callgraph node for NF.
-  CallGraphNode *NF_CGN = CG.getOrInsertFunction(NF);
-
-  while (!F->use_empty()) {
-    CallSite CS(*F->use_begin());
-    Instruction *Call = CS.getInstruction();
-
-    const AttrListPtr &PAL = F->getAttributes();
-    // Add any return attributes.
-    if (Attributes attrs = PAL.getRetAttributes())
-      ArgAttrsVec.push_back(AttributeWithIndex::get(0, attrs));
-
-    // Copy arguments, however skip first one.
-    CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
-    Value *FirstCArg = *AI;
-    ++AI;
-    // 0th parameter attribute is reserved for return type.
-    // 1th parameter attribute is for first 1st sret argument.
-    unsigned ParamIndex = 2; 
-    while (AI != AE) {
-      Args.push_back(*AI); 
-      if (Attributes Attrs = PAL.getParamAttributes(ParamIndex))
-        ArgAttrsVec.push_back(AttributeWithIndex::get(ParamIndex - 1, Attrs));
-      ++ParamIndex;
-      ++AI;
-    }
-
-    // Add any function attributes.
-    if (Attributes attrs = PAL.getFnAttributes())
-      ArgAttrsVec.push_back(AttributeWithIndex::get(~0, attrs));
-    
-    AttrListPtr NewPAL = AttrListPtr::get(ArgAttrsVec.begin(), ArgAttrsVec.end());
-    
-    // Build new call instruction.
-    Instruction *New;
-    if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) {
-      New = InvokeInst::Create(NF, II->getNormalDest(), II->getUnwindDest(),
-                               Args.begin(), Args.end(), "", Call);
-      cast<InvokeInst>(New)->setCallingConv(CS.getCallingConv());
-      cast<InvokeInst>(New)->setAttributes(NewPAL);
-    } else {
-      New = CallInst::Create(NF, Args.begin(), Args.end(), "", Call);
-      cast<CallInst>(New)->setCallingConv(CS.getCallingConv());
-      cast<CallInst>(New)->setAttributes(NewPAL);
-      if (cast<CallInst>(Call)->isTailCall())
-        cast<CallInst>(New)->setTailCall();
-    }
-    Args.clear();
-    ArgAttrsVec.clear();
-    New->takeName(Call);
-
-    // Update the callgraph to know that the callsite has been transformed.
-    CallGraphNode *CalleeNode = CG[Call->getParent()->getParent()];
-    CalleeNode->removeCallEdgeFor(Call);
-    CalleeNode->addCalledFunction(New, NF_CGN);
-    
-    // Update all users of sret parameter to extract value using extractvalue.
-    for (Value::use_iterator UI = FirstCArg->use_begin(), 
-           UE = FirstCArg->use_end(); UI != UE; ) {
-      User *U2 = *UI++;
-      CallInst *C2 = dyn_cast<CallInst>(U2);
-      if (C2 && (C2 == Call))
-        continue;
-      
-      GetElementPtrInst *UGEP = cast<GetElementPtrInst>(U2);
-      ConstantInt *Idx = cast<ConstantInt>(UGEP->getOperand(2));
-      Value *GR = ExtractValueInst::Create(New, Idx->getZExtValue(),
-                                           "evi", UGEP);
-      while(!UGEP->use_empty()) {
-        // isSafeToUpdateAllCallers has checked that all GEP uses are
-        // LoadInsts
-        LoadInst *L = cast<LoadInst>(*UGEP->use_begin());
-        L->replaceAllUsesWith(GR);
-        L->eraseFromParent();
-      }
-      UGEP->eraseFromParent();
-      continue;
-    }
-    Call->eraseFromParent();
-  }
-  
-  return NF_CGN;
-}
-