More refactoring. Move alloca instructions and handle invoke instructions

before we delete the original call site, allowing slight simplifications of
code, but nothing exciting.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11109 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 132 insertions, 129 deletions

diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp
index b60742a..107c6cd 100644
--- a/lib/Transforms/Utils/InlineFunction.cpp
+++ b/lib/Transforms/Utils/InlineFunction.cpp
@@ -50,153 +50,68 @@ bool llvm::InlineFunction(CallSite CS) {
   BasicBlock *OrigBB = TheCall->getParent();
   Function *Caller = OrigBB->getParent();
 
-  // Calculate the vector of arguments to pass into the function cloner...
-  std::map<const Value*, Value*> ValueMap;
-  assert(std::distance(CalledFunc->abegin(), CalledFunc->aend()) == 
-         std::distance(CS.arg_begin(), CS.arg_end()) &&
-         "No varargs calls can be inlined!");
-
-  CallSite::arg_iterator AI = CS.arg_begin();
-  for (Function::const_aiterator I = CalledFunc->abegin(), E=CalledFunc->aend();
-       I != E; ++I, ++AI)
-    ValueMap[I] = *AI;
-
   // Get an iterator to the last basic block in the function, which will have
   // the new function inlined after it.
   //
   Function::iterator LastBlock = &Caller->back();
 
-  // Clone the entire body of the callee into the caller.  Make sure to capture
-  // all of the return instructions from the cloned function.
+  // Make sure to capture all of the return instructions from the cloned
+  // function.
   std::vector<ReturnInst*> Returns;
-  CloneFunctionInto(Caller, CalledFunc, ValueMap, Returns, ".i");
-
+  { // Scope to destroy ValueMap after cloning.
+    // Calculate the vector of arguments to pass into the function cloner...
+    std::map<const Value*, Value*> ValueMap;
+    assert(std::distance(CalledFunc->abegin(), CalledFunc->aend()) == 
+           std::distance(CS.arg_begin(), CS.arg_end()) &&
+           "No varargs calls can be inlined!");
+    
+    CallSite::arg_iterator AI = CS.arg_begin();
+    for (Function::const_aiterator I = CalledFunc->abegin(),
+           E = CalledFunc->aend(); I != E; ++I, ++AI)
+      ValueMap[I] = *AI;
+    
+    // Clone the entire body of the callee into the caller.  
+    CloneFunctionInto(Caller, CalledFunc, ValueMap, Returns, ".i");
+  }    
   
-
-
-  // We want to clone the entire callee function into the hole between the
-  // "starter" and "ender" blocks.  How we accomplish this depends on whether
-  // this is an invoke instruction or a call instruction.
-
-  BasicBlock *InvokeDest = 0;     // Exception handling destination
-  std::vector<Value*> InvokeDestPHIValues; // Values for PHI nodes in InvokeDest
-  BasicBlock *AfterCallBB;
-
-  if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
-    InvokeDest = II->getExceptionalDest();
-
-    // If there are PHI nodes in the exceptional destination block, we need to
-    // keep track of which values came into them from this invoke, then remove
-    // the entry for this block.
-    for (BasicBlock::iterator I = InvokeDest->begin();
-         PHINode *PN = dyn_cast<PHINode>(I); ++I) {
-      // Save the value to use for this edge...
-      InvokeDestPHIValues.push_back(PN->getIncomingValueForBlock(OrigBB));
-    }
-
-    // Add an unconditional branch to make this look like the CallInst case...
-    BranchInst *NewBr = new BranchInst(II->getNormalDest(), TheCall);
-
-    // Split the basic block.  This guarantees that no PHI nodes will have to be
-    // updated due to new incoming edges, and make the invoke case more
-    // symmetric to the call case.
-    AfterCallBB = OrigBB->splitBasicBlock(NewBr,
-                                          CalledFunc->getName()+".entry");
-
-    // Remove (unlink) the InvokeInst from the function...
-    OrigBB->getInstList().remove(TheCall);
-
-  } else {  // It's a call
-    // If this is a call instruction, we need to split the basic block that the
-    // call lives in.
-    //
-    AfterCallBB = OrigBB->splitBasicBlock(TheCall,
-                                          CalledFunc->getName()+".entry");
-    // Remove (unlink) the CallInst from the function...
-    AfterCallBB->getInstList().remove(TheCall);
-  }
-
-  // If we have a return value generated by this call, convert it into a PHI 
-  // node that gets values from each of the old RET instructions in the original
-  // function.
-  //
-  if (!TheCall->use_empty()) {
-    // We only need to make the PHI if there is more than one return instruction
-    if (Returns.size() > 1) {
-      // The PHI node should go at the front of the new basic block to merge all
-      // possible incoming values.
-      //
-      PHINode *PHI = new PHINode(CalledFunc->getReturnType(),
-                                 TheCall->getName(), AfterCallBB->begin());
-
-      // Anything that used the result of the function call should now use the
-      // PHI node as their operand.
-      //
-      TheCall->replaceAllUsesWith(PHI);
-
-      // Add all of the return instructions as entries in the PHI node.
-      for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
-        ReturnInst *RI = Returns[i];
-
-        assert(RI->getReturnValue() && "Ret should have value!");
-        assert(RI->getReturnValue()->getType() == PHI->getType() && 
-               "Ret value not consistent in function!");
-        PHI->addIncoming(RI->getReturnValue(), RI->getParent());
-      }
-
-    } else if (!Returns.empty()) {
-      // Otherwise, if there is exactly one return value, just replace anything
-      // using the return value of the call with the computed value.
-      TheCall->replaceAllUsesWith(Returns[0]->getReturnValue());
-    }
-  }
-
-  // Since we are now done with the Call/Invoke, we can delete it.
-  delete TheCall;
-
-  // Loop over all of the return instructions, turning them into unconditional
-  // branches to the merge point now...
-  for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
-    ReturnInst *RI = Returns[i];
-
-    // Add a branch to the merge point where the PHI node lives if it exists.
-    new BranchInst(AfterCallBB, RI);
-
-    // Delete the return instruction now
-    RI->getParent()->getInstList().erase(RI);
-  }
-
-  // Change the branch that used to go to AfterCallBB to branch to the first
-  // basic block of the inlined function.
-  //
-  TerminatorInst *Br = OrigBB->getTerminator();
-  assert(Br && Br->getOpcode() == Instruction::Br && 
-	 "splitBasicBlock broken!");
-  Br->setOperand(0, ++LastBlock);
+  // Remember the first block that is newly cloned over.
+  Function::iterator FirstNewBlock = LastBlock; ++FirstNewBlock;
 
   // If there are any alloca instructions in the block that used to be the entry
   // block for the callee, move them to the entry block of the caller.  First
   // calculate which instruction they should be inserted before.  We insert the
   // instructions at the end of the current alloca list.
   //
-  if (isa<AllocaInst>(LastBlock->begin())) {
+  if (isa<AllocaInst>(FirstNewBlock->begin())) {
     BasicBlock::iterator InsertPoint = Caller->begin()->begin();
     while (isa<AllocaInst>(InsertPoint)) ++InsertPoint;
     
-    for (BasicBlock::iterator I = LastBlock->begin(), E = LastBlock->end();
-         I != E; )
+    for (BasicBlock::iterator I = FirstNewBlock->begin(),
+           E = FirstNewBlock->end(); I != E; )
       if (AllocaInst *AI = dyn_cast<AllocaInst>(I++))
         if (isa<Constant>(AI->getArraySize())) {
-          LastBlock->getInstList().remove(AI);
+          FirstNewBlock->getInstList().remove(AI);
           Caller->front().getInstList().insert(InsertPoint, AI);      
         }
   }
 
-  // If we just inlined a call due to an invoke instruction, scan the inlined
-  // function checking for function calls that should now be made into invoke
-  // instructions, and for unwind's which should be turned into branches.
-  if (InvokeDest) {
-    for (Function::iterator BB = LastBlock, E = Caller->end(); BB != E; ++BB) {
+  // If we are inlining for an invoke instruction, we must make sure to rewrite
+  // any inlined 'unwind' instructions into branches to the invoke exception
+  // destination, and call instructions into invoke instructions.
+  if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
+    BasicBlock *InvokeDest = II->getExceptionalDest();
+    std::vector<Value*> InvokeDestPHIValues;
+
+    // If there are PHI nodes in the exceptional destination block, we need to
+    // keep track of which values came into them from this invoke, then remove
+    // the entry for this block.
+    for (BasicBlock::iterator I = InvokeDest->begin();
+         PHINode *PN = dyn_cast<PHINode>(I); ++I)
+      // Save the value to use for this edge...
+      InvokeDestPHIValues.push_back(PN->getIncomingValueForBlock(OrigBB));
+
+    for (Function::iterator BB = FirstNewBlock, E = Caller->end();
+         BB != E; ++BB) {
       for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
         // We only need to check for function calls: inlined invoke instructions
         // require no special handling...
@@ -257,16 +172,104 @@ bool llvm::InlineFunction(CallSite CS) {
     // the exception destination block still have entries due to the original
     // invoke instruction.  Eliminate these entries (which might even delete the
     // PHI node) now.
-    for (BasicBlock::iterator I = InvokeDest->begin();
-         PHINode *PN = dyn_cast<PHINode>(I); ++I)
-      PN->removeIncomingValue(AfterCallBB);
+    InvokeDest->removePredecessor(II->getParent());
   }
+
+  // We want to clone the entire callee function into the hole between the
+  // "starter" and "ender" blocks.  How we accomplish this depends on whether
+  // this is an invoke instruction or a call instruction.
+  BasicBlock *AfterCallBB;
+  if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
+
+    // Add an unconditional branch to make this look like the CallInst case...
+    BranchInst *NewBr = new BranchInst(II->getNormalDest(), TheCall);
+
+    // Split the basic block.  This guarantees that no PHI nodes will have to be
+    // updated due to new incoming edges, and make the invoke case more
+    // symmetric to the call case.
+    AfterCallBB = OrigBB->splitBasicBlock(NewBr,
+                                          CalledFunc->getName()+".entry");
+
+    // Remove (unlink) the InvokeInst from the function...
+    OrigBB->getInstList().remove(TheCall);
+
+  } else {  // It's a call
+    // If this is a call instruction, we need to split the basic block that the
+    // call lives in.
+    //
+    AfterCallBB = OrigBB->splitBasicBlock(TheCall,
+                                          CalledFunc->getName()+".entry");
+    // Remove (unlink) the CallInst from the function...
+    AfterCallBB->getInstList().remove(TheCall);
+  }
+
+  // Handle all of the return instructions that we just cloned in, and eliminate
+  // any users of the original call/invoke instruction.
+  if (Returns.size() > 1) {
+    // The PHI node should go at the front of the new basic block to merge all
+    // possible incoming values.
+    //
+    PHINode *PHI = 0;
+    if (!TheCall->use_empty()) {
+      PHI = new PHINode(CalledFunc->getReturnType(),
+                        TheCall->getName(), AfterCallBB->begin());
+      
+      // Anything that used the result of the function call should now use the
+      // PHI node as their operand.
+      //
+      TheCall->replaceAllUsesWith(PHI);
+    }
+
+    // Loop over all of the return instructions, turning them into unconditional
+    // branches to the merge point now, and adding entries to the PHI node as
+    // appropriate.
+    for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
+      ReturnInst *RI = Returns[i];
+
+      if (PHI) {
+        assert(RI->getReturnValue() && "Ret should have value!");
+        assert(RI->getReturnValue()->getType() == PHI->getType() && 
+               "Ret value not consistent in function!");
+        PHI->addIncoming(RI->getReturnValue(), RI->getParent());
+      }
+
+      // Add a branch to the merge point where the PHI node lives if it exists.
+      new BranchInst(AfterCallBB, RI);
+      
+      // Delete the return instruction now
+      RI->getParent()->getInstList().erase(RI);
+    }
+    
+  } else if (!Returns.empty()) {
+    // Otherwise, if there is exactly one return value, just replace anything
+    // using the return value of the call with the computed value.
+    if (!TheCall->use_empty())
+      TheCall->replaceAllUsesWith(Returns[0]->getReturnValue());
+
+    // Add a branch to the merge point where the PHI node lives if it exists.
+    new BranchInst(AfterCallBB, Returns[0]);
+
+    // Delete the return instruction now
+    Returns[0]->getParent()->getInstList().erase(Returns[0]);
+  }
+
+  // Since we are now done with the Call/Invoke, we can delete it.
+  delete TheCall;
+
+  // Change the branch that used to go to AfterCallBB to branch to the first
+  // basic block of the inlined function.
+  //
+  TerminatorInst *Br = OrigBB->getTerminator();
+  assert(Br && Br->getOpcode() == Instruction::Br && 
+	 "splitBasicBlock broken!");
+  Br->setOperand(0, FirstNewBlock);
+
   // Now that the function is correct, make it a little bit nicer.  In
   // particular, move the basic blocks inserted from the end of the function
   // into the space made by splitting the source basic block.
   //
   Caller->getBasicBlockList().splice(AfterCallBB, Caller->getBasicBlockList(), 
-                                     LastBlock, Caller->end());
+                                     FirstNewBlock, Caller->end());
 
   // We should always be able to fold the entry block of the function into the
   // single predecessor of the block...