[llvm-commits] [release_12] CVS: llvm/lib/Transforms/Utils/CodeExtractor.cpp

John Criswell criswell at cs.uiuc.edu
Thu Mar 18 10:43:20 PST 2004


Changes in directory llvm/lib/Transforms/Utils:

CodeExtractor.cpp updated: 1.10 -> 1.10.2.1

---
Log message:

Updated code from trunk.



---
Diffs of the changes:  (+104 -210)

Index: llvm/lib/Transforms/Utils/CodeExtractor.cpp
diff -u llvm/lib/Transforms/Utils/CodeExtractor.cpp:1.10 llvm/lib/Transforms/Utils/CodeExtractor.cpp:1.10.2.1
--- llvm/lib/Transforms/Utils/CodeExtractor.cpp:1.10	Sun Mar 14 19:26:44 2004
+++ llvm/lib/Transforms/Utils/CodeExtractor.cpp	Thu Mar 18 10:41:44 2004
@@ -13,16 +13,16 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/BasicBlock.h"
+#include "llvm/Transforms/Utils/FunctionUtils.h"
 #include "llvm/Constants.h"
 #include "llvm/DerivedTypes.h"
 #include "llvm/Instructions.h"
 #include "llvm/Module.h"
 #include "llvm/Pass.h"
+#include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/Verifier.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/FunctionUtils.h"
 #include "Support/Debug.h"
 #include "Support/StringExtras.h"
 #include <algorithm>
@@ -30,22 +30,13 @@
 using namespace llvm;
 
 namespace {
-
-  /// getFunctionArg - Return a pointer to F's ARGNOth argument.
-  ///
-  Argument *getFunctionArg(Function *F, unsigned argno) {
-    Function::aiterator I = F->abegin();
-    std::advance(I, argno);
-    return I;
-  }
-
-  struct CodeExtractor {
+  class CodeExtractor {
     typedef std::vector<Value*> Values;
-    typedef std::vector<std::pair<unsigned, unsigned> > PhiValChangesTy;
-    typedef std::map<PHINode*, PhiValChangesTy> PhiVal2ArgTy;
-    PhiVal2ArgTy PhiVal2Arg;
     std::set<BasicBlock*> BlocksToExtract;
+    DominatorSet *DS;
   public:
+    CodeExtractor(DominatorSet *ds = 0) : DS(ds) {}
+
     Function *ExtractCodeRegion(const std::vector<BasicBlock*> &code);
 
   private:
@@ -53,15 +44,9 @@
                            BasicBlock *newHeader,
                            BasicBlock *newRootNode);
 
-    void processPhiNodeInputs(PHINode *Phi,
-                              Values &inputs,
-                              BasicBlock *newHeader,
-                              BasicBlock *newRootNode);
-
-    void rewritePhiNodes(Function *F, BasicBlock *newFuncRoot);
-
     Function *constructFunction(const Values &inputs,
                                 const Values &outputs,
+                                BasicBlock *header,
                                 BasicBlock *newRootNode, BasicBlock *newHeader,
                                 Function *oldFunction, Module *M);
 
@@ -75,95 +60,6 @@
   };
 }
 
-void CodeExtractor::processPhiNodeInputs(PHINode *Phi,
-                                         Values &inputs,
-                                         BasicBlock *codeReplacer,
-                                         BasicBlock *newFuncRoot) {
-  // Separate incoming values and BasicBlocks as internal/external. We ignore
-  // the case where both the value and BasicBlock are internal, because we don't
-  // need to do a thing.
-  std::vector<unsigned> EValEBB;
-  std::vector<unsigned> EValIBB;
-  std::vector<unsigned> IValEBB;
-
-  for (unsigned i = 0, e = Phi->getNumIncomingValues(); i != e; ++i) {
-    Value *phiVal = Phi->getIncomingValue(i);
-    if (Instruction *Inst = dyn_cast<Instruction>(phiVal)) {
-      if (BlocksToExtract.count(Inst->getParent())) {
-        if (!BlocksToExtract.count(Phi->getIncomingBlock(i)))
-          IValEBB.push_back(i);
-      } else {
-        if (BlocksToExtract.count(Phi->getIncomingBlock(i)))
-          EValIBB.push_back(i);
-        else
-          EValEBB.push_back(i);
-      }
-    } else if (Argument *Arg = dyn_cast<Argument>(phiVal)) {
-      // arguments are external
-      if (BlocksToExtract.count(Phi->getIncomingBlock(i)))
-        EValIBB.push_back(i);
-      else
-        EValEBB.push_back(i);
-    } else {
-      // Globals/Constants are internal, but considered `external' if they are
-      // coming from an external block.
-      if (!BlocksToExtract.count(Phi->getIncomingBlock(i)))
-        EValEBB.push_back(i);
-    }
-  }
-
-  // Both value and block are external. Need to group all of these, have an
-  // external phi, pass the result as an argument, and have THIS phi use that
-  // result.
-  if (EValEBB.size() > 0) {
-    if (EValEBB.size() == 1) {
-      // Now if it's coming from the newFuncRoot, it's that funky input
-      unsigned phiIdx = EValEBB[0];
-      if (!isa<Constant>(Phi->getIncomingValue(phiIdx))) {
-        PhiVal2Arg[Phi].push_back(std::make_pair(phiIdx, inputs.size()));
-        // We can just pass this value in as argument
-        inputs.push_back(Phi->getIncomingValue(phiIdx));
-      }
-      Phi->setIncomingBlock(phiIdx, newFuncRoot);
-    } else {
-      PHINode *externalPhi = new PHINode(Phi->getType(), "extPhi");
-      codeReplacer->getInstList().insert(codeReplacer->begin(), externalPhi);
-      for (std::vector<unsigned>::iterator i = EValEBB.begin(),
-             e = EValEBB.end(); i != e; ++i) {
-        externalPhi->addIncoming(Phi->getIncomingValue(*i),
-                                 Phi->getIncomingBlock(*i));
-
-        // We make these values invalid instead of deleting them because that
-        // would shift the indices of other values... The fixPhiNodes should
-        // clean these phi nodes up later.
-        Phi->setIncomingValue(*i, 0);
-        Phi->setIncomingBlock(*i, 0);
-      }
-      PhiVal2Arg[Phi].push_back(std::make_pair(Phi->getNumIncomingValues(),
-                                               inputs.size()));
-      // We can just pass this value in as argument
-      inputs.push_back(externalPhi);
-    }
-  }
-
-  // When the value is external, but block internal...  just pass it in as
-  // argument, no change to phi node
-  for (std::vector<unsigned>::iterator i = EValIBB.begin(),
-         e = EValIBB.end(); i != e; ++i) {
-    // rewrite the phi input node to be an argument
-    PhiVal2Arg[Phi].push_back(std::make_pair(*i, inputs.size()));
-    inputs.push_back(Phi->getIncomingValue(*i));
-  }
-
-  // Value internal, block external this can happen if we are extracting a part
-  // of a loop.
-  for (std::vector<unsigned>::iterator i = IValEBB.begin(),
-         e = IValEBB.end(); i != e; ++i) {
-    assert(0 && "Cannot (YET) handle internal values via external blocks");
-  }
-}
-
-
 void CodeExtractor::findInputsOutputs(Values &inputs, Values &outputs,
                                       BasicBlock *newHeader,
                                       BasicBlock *newRootNode) {
@@ -173,8 +69,18 @@
     for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
       // If a used value is defined outside the region, it's an input.  If an
       // instruction is used outside the region, it's an output.
-      if (PHINode *Phi = dyn_cast<PHINode>(I)) {
-        processPhiNodeInputs(Phi, inputs, newHeader, newRootNode);
+      if (PHINode *PN = dyn_cast<PHINode>(I)) {
+        for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
+          Value *V = PN->getIncomingValue(i);
+          if (!BlocksToExtract.count(PN->getIncomingBlock(i)) &&
+              (isa<Instruction>(V) || isa<Argument>(V)))
+            inputs.push_back(V);
+          else if (Instruction *opI = dyn_cast<Instruction>(V)) {
+            if (!BlocksToExtract.count(opI->getParent()))
+              inputs.push_back(opI);
+          } else if (isa<Argument>(V))
+            inputs.push_back(V);
+        }
       } else {
         // All other instructions go through the generic input finder
         // Loop over the operands of each instruction (inputs)
@@ -192,59 +98,26 @@
       // Consider uses of this instruction (outputs)
       for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
            UI != E; ++UI)
-        if (!BlocksToExtract.count(cast<Instruction>(*UI)->getParent()))
-          outputs.push_back(*UI);
+        if (!BlocksToExtract.count(cast<Instruction>(*UI)->getParent())) {
+          outputs.push_back(I);
+          break;
+        }
     } // for: insts
   } // for: basic blocks
 }
 
-void CodeExtractor::rewritePhiNodes(Function *F,
-                                    BasicBlock *newFuncRoot) {
-  // Write any changes that were saved before: use function arguments as inputs
-  for (PhiVal2ArgTy::iterator i = PhiVal2Arg.begin(), e = PhiVal2Arg.end();
-       i != e; ++i) {
-    PHINode *phi = i->first;
-    PhiValChangesTy &values = i->second;
-    for (unsigned cIdx = 0, ce = values.size(); cIdx != ce; ++cIdx)
-    {
-      unsigned phiValueIdx = values[cIdx].first, argNum = values[cIdx].second;
-      if (phiValueIdx < phi->getNumIncomingValues())
-        phi->setIncomingValue(phiValueIdx, getFunctionArg(F, argNum));
-      else
-        phi->addIncoming(getFunctionArg(F, argNum), newFuncRoot);
-    }
-  }
-
-  // Delete any invalid Phi node inputs that were marked as NULL previously
-  for (PhiVal2ArgTy::iterator i = PhiVal2Arg.begin(), e = PhiVal2Arg.end();
-       i != e; ++i) {
-    PHINode *phi = i->first;
-    for (unsigned idx = 0, end = phi->getNumIncomingValues(); idx != end; ++idx)
-    {
-      if (phi->getIncomingValue(idx) == 0 && phi->getIncomingBlock(idx) == 0) {
-        phi->removeIncomingValue(idx);
-        --idx;
-        --end;
-      }
-    }
-  }
-
-  // We are done with the saved values
-  PhiVal2Arg.clear();
-}
-
-
 /// constructFunction - make a function based on inputs and outputs, as follows:
 /// f(in0, ..., inN, out0, ..., outN)
 ///
 Function *CodeExtractor::constructFunction(const Values &inputs,
                                            const Values &outputs,
+                                           BasicBlock *header,
                                            BasicBlock *newRootNode,
                                            BasicBlock *newHeader,
-                                           Function *oldFunction, Module *M) {
+                                           Function *oldFunction,
+                                           Module *M) {
   DEBUG(std::cerr << "inputs: " << inputs.size() << "\n");
   DEBUG(std::cerr << "outputs: " << outputs.size() << "\n");
-  BasicBlock *header = *BlocksToExtract.begin();
 
   // This function returns unsigned, outputs will go back by reference.
   Type *retTy = Type::UShortTy;
@@ -258,18 +131,11 @@
     paramTy.push_back(value->getType());
   }
 
-  // Add the types of the output values to the function's argument list, but
-  // make them pointer types for scalars
-  for (Values::const_iterator i = outputs.begin(),
-         e = outputs.end(); i != e; ++i) {
-    const Value *value = *i;
-    DEBUG(std::cerr << "instr used in func: " << value << "\n");
-    const Type *valueType = value->getType();
-    // Convert scalar types into a pointer of that type
-    if (valueType->isPrimitiveType()) {
-      valueType = PointerType::get(valueType);
-    }
-    paramTy.push_back(valueType);
+  // Add the types of the output values to the function's argument list.
+  for (Values::const_iterator I = outputs.begin(), E = outputs.end();
+       I != E; ++I) {
+    DEBUG(std::cerr << "instr used in func: " << *I << "\n");
+    paramTy.push_back(PointerType::get((*I)->getType()));
   }
 
   DEBUG(std::cerr << "Function type: " << retTy << " f(");
@@ -286,30 +152,37 @@
                                        oldFunction->getName() + "_code", M);
   newFunction->getBasicBlockList().push_back(newRootNode);
 
-  for (unsigned i = 0, e = inputs.size(); i != e; ++i) {
+  // Create an iterator to name all of the arguments we inserted.
+  Function::aiterator AI = newFunction->abegin();
+
+  // Rewrite all users of the inputs in the extracted region to use the
+  // arguments instead.
+  for (unsigned i = 0, e = inputs.size(); i != e; ++i, ++AI) {
+    AI->setName(inputs[i]->getName());
     std::vector<User*> Users(inputs[i]->use_begin(), inputs[i]->use_end());
     for (std::vector<User*>::iterator use = Users.begin(), useE = Users.end();
          use != useE; ++use)
       if (Instruction* inst = dyn_cast<Instruction>(*use))
         if (BlocksToExtract.count(inst->getParent()))
-          inst->replaceUsesOfWith(inputs[i], getFunctionArg(newFunction, i));
+          inst->replaceUsesOfWith(inputs[i], AI);
   }
 
+  // Set names for all of the output arguments.
+  for (unsigned i = 0, e = outputs.size(); i != e; ++i, ++AI)
+    AI->setName(outputs[i]->getName()+".out");  
+
+
   // Rewrite branches to basic blocks outside of the loop to new dummy blocks
   // within the new function. This must be done before we lose track of which
   // blocks were originally in the code region.
   std::vector<User*> Users(header->use_begin(), header->use_end());
-  for (std::vector<User*>::iterator i = Users.begin(), e = Users.end();
-       i != e; ++i) {
-    if (BranchInst *inst = dyn_cast<BranchInst>(*i)) {
-      BasicBlock *BB = inst->getParent();
-      if (!BlocksToExtract.count(BB) && BB->getParent() == oldFunction) {
-        // The BasicBlock which contains the branch is not in the region
-        // modify the branch target to a new block
-        inst->replaceUsesOfWith(header, newHeader);
-      }
-    }
-  }
+  for (unsigned i = 0, e = Users.size(); i != e; ++i)
+    // The BasicBlock which contains the branch is not in the region
+    // modify the branch target to a new block
+    if (TerminatorInst *TI = dyn_cast<TerminatorInst>(Users[i]))
+      if (!BlocksToExtract.count(TI->getParent()) &&
+          TI->getParent()->getParent() == oldFunction)
+        TI->replaceUsesOfWith(header, newHeader);
 
   return newFunction;
 }
@@ -333,34 +206,30 @@
 CodeExtractor::emitCallAndSwitchStatement(Function *newFunction,
                                           BasicBlock *codeReplacer,
                                           Values &inputs,
-                                          Values &outputs)
-{
+                                          Values &outputs) {
   // Emit a call to the new function, passing allocated memory for outputs and
   // just plain inputs for non-scalars
   std::vector<Value*> params(inputs);
 
-  for (Values::const_iterator i = outputs.begin(), e = outputs.end(); i != e;
-       ++i) {
-    Value *Output = *i;
+  // Get an iterator to the first output argument.
+  Function::aiterator OutputArgBegin = newFunction->abegin();
+  std::advance(OutputArgBegin, inputs.size());
+
+  for (unsigned i = 0, e = outputs.size(); i != e; ++i) {
+    Value *Output = outputs[i];
     // Create allocas for scalar outputs
-    if (Output->getType()->isPrimitiveType()) {
-      AllocaInst *alloca =
-        new AllocaInst((*i)->getType(), 0, Output->getName()+".loc",
-                       codeReplacer->getParent()->begin()->begin());
-      params.push_back(alloca);
-
-      LoadInst *load = new LoadInst(alloca, Output->getName()+".reload");
-      codeReplacer->getInstList().push_back(load);
-      std::vector<User*> Users((*i)->use_begin(), (*i)->use_end());
-      for (std::vector<User*>::iterator use = Users.begin(), useE =Users.end();
-           use != useE; ++use) {
-        if (Instruction* inst = dyn_cast<Instruction>(*use)) {
-          if (!BlocksToExtract.count(inst->getParent()))
-            inst->replaceUsesOfWith(*i, load);
-        }
-      }
-    } else {
-      params.push_back(*i);
+    AllocaInst *alloca =
+      new AllocaInst(outputs[i]->getType(), 0, Output->getName()+".loc",
+                     codeReplacer->getParent()->begin()->begin());
+    params.push_back(alloca);
+    
+    LoadInst *load = new LoadInst(alloca, Output->getName()+".reload");
+    codeReplacer->getInstList().push_back(load);
+    std::vector<User*> Users(outputs[i]->use_begin(), outputs[i]->use_end());
+    for (unsigned u = 0, e = Users.size(); u != e; ++u) {
+      Instruction *inst = cast<Instruction>(Users[u]);
+      if (!BlocksToExtract.count(inst->getParent()))
+        inst->replaceUsesOfWith(outputs[i], load);
     }
   }
 
@@ -400,8 +269,12 @@
 
           // Restore values just before we exit
           // FIXME: Use a GetElementPtr to bunch the outputs in a struct
-          for (unsigned out = 0, e = outputs.size(); out != e; ++out)
-            new StoreInst(outputs[out], getFunctionArg(newFunction, out),NTRet);
+          Function::aiterator OAI = OutputArgBegin;
+          for (unsigned out = 0, e = outputs.size(); out != e; ++out, ++OAI)
+            if (!DS ||
+                DS->dominates(cast<Instruction>(outputs[out])->getParent(),
+                              TI->getParent()))
+              new StoreInst(outputs[out], OAI, NTRet);
         }
 
         // rewrite the original branch instruction with this new target
@@ -486,16 +359,36 @@
 
   // Step 2: Construct new function based on inputs/outputs,
   // Add allocas for all defs
-  Function *newFunction = constructFunction(inputs, outputs, newFuncRoot, 
+  Function *newFunction = constructFunction(inputs, outputs, code[0],
+                                            newFuncRoot, 
                                             codeReplacer, oldFunction,
                                             oldFunction->getParent());
 
-  rewritePhiNodes(newFunction, newFuncRoot);
-
   emitCallAndSwitchStatement(newFunction, codeReplacer, inputs, outputs);
 
   moveCodeToFunction(newFunction);
 
+  // Loop over all of the PHI nodes in the entry block (code[0]), and change any
+  // references to the old incoming edge to be the new incoming edge.
+  for (BasicBlock::iterator I = code[0]->begin();
+       PHINode *PN = dyn_cast<PHINode>(I); ++I)
+    for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+      if (!BlocksToExtract.count(PN->getIncomingBlock(i)))
+        PN->setIncomingBlock(i, newFuncRoot);
+
+  // Look at all successors of the codeReplacer block.  If any of these blocks
+  // had PHI nodes in them, we need to update the "from" block to be the code
+  // replacer, not the original block in the extracted region.
+  std::vector<BasicBlock*> Succs(succ_begin(codeReplacer),
+                                 succ_end(codeReplacer));
+  for (unsigned i = 0, e = Succs.size(); i != e; ++i)
+    for (BasicBlock::iterator I = Succs[i]->begin();
+         PHINode *PN = dyn_cast<PHINode>(I); ++I)
+      for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+        if (BlocksToExtract.count(PN->getIncomingBlock(i)))
+          PN->setIncomingBlock(i, codeReplacer);
+  
+
   DEBUG(if (verifyFunction(*newFunction)) abort());
   return newFunction;
 }
@@ -503,14 +396,15 @@
 /// ExtractCodeRegion - slurp a sequence of basic blocks into a brand new
 /// function
 ///
-Function* llvm::ExtractCodeRegion(const std::vector<BasicBlock*> &code) {
-  return CodeExtractor().ExtractCodeRegion(code);
+Function* llvm::ExtractCodeRegion(DominatorSet &DS,
+                                  const std::vector<BasicBlock*> &code) {
+  return CodeExtractor(&DS).ExtractCodeRegion(code);
 }
 
 /// ExtractBasicBlock - slurp a natural loop into a brand new function
 ///
-Function* llvm::ExtractLoop(Loop *L) {
-  return CodeExtractor().ExtractCodeRegion(L->getBlocks());
+Function* llvm::ExtractLoop(DominatorSet &DS, Loop *L) {
+  return CodeExtractor(&DS).ExtractCodeRegion(L->getBlocks());
 }
 
 /// ExtractBasicBlock - slurp a basic block into a brand new function





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