-//===- MethodInlining.cpp - Code to perform method inlining ---------------===//
+//===- InlineSimple.cpp - Code to perform simple function inlining --------===//
//
-// This file implements inlining of methods.
+// The LLVM Compiler Infrastructure
//
-// Specifically, this:
-// * Exports functionality to inline any method call
-// * Inlines methods that consist of a single basic block
-// * Is able to inline ANY method call
-// . Has a smart heuristic for when to inline a method
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
-// Notice that:
-// * This pass has a habit of introducing duplicated constant pool entries,
-// and also opens up a lot of opportunities for constant propogation. It is
-// a good idea to to run a constant propogation pass, then a DCE pass
-// sometime after running this pass.
+//===----------------------------------------------------------------------===//
//
-// TODO: Currently this throws away all of the symbol names in the method being
-// inlined to try to avoid name clashes. Use a name if it's not taken
+// This file implements bottom-up inlining of functions into callees.
//
//===----------------------------------------------------------------------===//
-#include "llvm/Optimizations/MethodInlining.h"
+#define DEBUG_TYPE "inline"
+#include "llvm/CallingConv.h"
+#include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
#include "llvm/Module.h"
-#include "llvm/Method.h"
-#include "llvm/iTerminators.h"
-#include "llvm/iOther.h"
-#include <algorithm>
-#include <map>
-
-#include "llvm/Assembly/Writer.h"
-
-using namespace opt;
-
-// RemapInstruction - Convert the instruction operands from referencing the
-// current values into those specified by ValueMap.
-//
-static inline void RemapInstruction(Instruction *I,
- map<const Value *, Value*> &ValueMap) {
-
- for (unsigned op = 0, E = I->getNumOperands(); op != E; ++op) {
- const Value *Op = I->getOperand(op);
- Value *V = ValueMap[Op];
- if (!V && (isa<Method>(Op) || isa<ConstPoolVal>(Op)))
- continue; // Methods and constants don't get relocated
-
- if (!V) {
- cerr << "Val = " << endl << Op << "Addr = " << (void*)Op << endl;
- cerr << "Inst = " << I;
+#include "llvm/Type.h"
+#include "llvm/Analysis/CallGraph.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/IPO/InlinerPass.h"
+#include "llvm/Transforms/Utils/InlineCost.h"
+#include "llvm/ADT/SmallPtrSet.h"
+
+using namespace llvm;
+
+namespace {
+
+ class VISIBILITY_HIDDEN SimpleInliner : public Inliner {
+ // Functions that are never inlined
+ SmallPtrSet<const Function*, 16> NeverInline;
+ InlineCostAnalyzer CA;
+ public:
+ SimpleInliner() : Inliner(&ID) {}
+ SimpleInliner(int Threshold) : Inliner(&ID, Threshold) {}
+ static char ID; // Pass identification, replacement for typeid
+ int getInlineCost(CallSite CS) {
+ return CA.getInlineCost(CS, NeverInline);
}
- assert(V && "Referenced value not in value map!");
- I->setOperand(op, V);
- }
+ virtual bool doInitialization(CallGraph &CG);
+ };
+ char SimpleInliner::ID = 0;
+ RegisterPass<SimpleInliner> X("inline", "Function Integration/Inlining");
}
-// InlineMethod - This function forcibly inlines the called method into the
-// basic block of the caller. This returns false if it is not possible to
-// inline this call. The program is still in a well defined state if this
-// occurs though.
-//
-// Note that this only does one level of inlining. For example, if the
-// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
-// exists in the instruction stream. Similiarly this will inline a recursive
-// method by one level.
-//
-bool opt::InlineMethod(BasicBlock::iterator CIIt) {
- assert((*CIIt)->getOpcode() == Instruction::Call &&
- "InlineMethod only works on CallInst nodes!");
- assert((*CIIt)->getParent() && "Instruction not embedded in basic block!");
- assert((*CIIt)->getParent()->getParent() && "Instruction not in method!");
-
- CallInst *CI = (CallInst*)*CIIt;
- const Method *CalledMeth = CI->getCalledMethod();
- if (CalledMeth->isExternal()) return false; // Can't inline external method!
- Method *CurrentMeth = CI->getParent()->getParent();
-
- //cerr << "Inlining " << CalledMeth->getName() << " into "
- // << CurrentMeth->getName() << endl;
-
- BasicBlock *OrigBB = CI->getParent();
-
- // Call splitBasicBlock - The original basic block now ends at the instruction
- // immediately before the call. The original basic block now ends with an
- // unconditional branch to NewBB, and NewBB starts with the call instruction.
- //
- BasicBlock *NewBB = OrigBB->splitBasicBlock(CIIt);
-
- // Remove (unlink) the CallInst from the start of the new basic block.
- NewBB->getInstList().remove(CI);
+Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
- // 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
- // method.
- //
- PHINode *PHI = 0;
- if (CalledMeth->getReturnType() != Type::VoidTy) {
- PHI = new PHINode(CalledMeth->getReturnType(), CI->getName());
-
- // The PHI node should go at the front of the new basic block to merge all
- // possible incoming values.
- //
- NewBB->getInstList().push_front(PHI);
-
- // Anything that used the result of the function call should now use the PHI
- // node as their operand.
- //
- CI->replaceAllUsesWith(PHI);
- }
-
- // Keep a mapping between the original method's values and the new duplicated
- // code's values. This includes all of: Method arguments, instruction values,
- // constant pool entries, and basic blocks.
- //
- map<const Value *, Value*> ValueMap;
+Pass *llvm::createFunctionInliningPass(int Threshold) {
+ return new SimpleInliner(Threshold);
+}
- // Add the method arguments to the mapping: (start counting at 1 to skip the
- // method reference itself)
- //
- Method::ArgumentListType::const_iterator PTI =
- CalledMeth->getArgumentList().begin();
- for (unsigned a = 1, E = CI->getNumOperands(); a != E; ++a, ++PTI)
- ValueMap[*PTI] = CI->getOperand(a);
+// doInitialization - Initializes the vector of functions that have been
+// annotated with the noinline attribute.
+bool SimpleInliner::doInitialization(CallGraph &CG) {
+
+ Module &M = CG.getModule();
- ValueMap[NewBB] = NewBB; // Returns get converted to reference NewBB
+ // Get llvm.noinline
+ GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
+
+ if (GV == 0)
+ return false;
- // Loop over all of the basic blocks in the method, inlining them as
- // appropriate. Keep track of the first basic block of the method...
- //
- for (Method::const_iterator BI = CalledMeth->begin();
- BI != CalledMeth->end(); ++BI) {
- const BasicBlock *BB = *BI;
- assert(BB->getTerminator() && "BasicBlock doesn't have terminator!?!?");
+ // Don't crash on invalid code
+ if (!GV->hasInitializer())
+ return false;
+
+ const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
+
+ if (InitList == 0)
+ return false;
+
+ // Iterate over each element and add to the NeverInline set
+ for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
+
+ // Get Source
+ const Constant *Elt = InitList->getOperand(i);
+
+ if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
+ if (CE->getOpcode() == Instruction::BitCast)
+ Elt = CE->getOperand(0);
- // Create a new basic block to copy instructions into!
- BasicBlock *IBB = new BasicBlock("", NewBB->getParent());
-
- ValueMap[*BI] = IBB; // Add basic block mapping.
-
- // Make sure to capture the mapping that a return will use...
- // TODO: This assumes that the RET is returning a value computed in the same
- // basic block as the return was issued from!
- //
- const TerminatorInst *TI = BB->getTerminator();
-
- // Loop over all instructions copying them over...
- Instruction *NewInst;
- for (BasicBlock::const_iterator II = BB->begin();
- II != (BB->end()-1); ++II) {
- IBB->getInstList().push_back((NewInst = (*II)->clone()));
- ValueMap[*II] = NewInst; // Add instruction map to value.
- }
-
- // Copy over the terminator now...
- switch (TI->getOpcode()) {
- case Instruction::Ret: {
- const ReturnInst *RI = (const ReturnInst*)TI;
-
- if (PHI) { // The PHI node should include this value!
- assert(RI->getReturnValue() && "Ret should have value!");
- assert(RI->getReturnValue()->getType() == PHI->getType() &&
- "Ret value not consistent in method!");
- PHI->addIncoming((Value*)RI->getReturnValue(), (BasicBlock*)BB);
- }
-
- // Add a branch to the code that was after the original Call.
- IBB->getInstList().push_back(new BranchInst(NewBB));
- break;
- }
- case Instruction::Br:
- IBB->getInstList().push_back(TI->clone());
- break;
-
- default:
- cerr << "MethodInlining: Don't know how to handle terminator: " << TI;
- abort();
- }
- }
-
-
- // Loop over all of the instructions in the method, fixing up operand
- // references as we go. This uses ValueMap to do all the hard work.
- //
- for (Method::const_iterator BI = CalledMeth->begin();
- BI != CalledMeth->end(); ++BI) {
- const BasicBlock *BB = *BI;
- BasicBlock *NBB = (BasicBlock*)ValueMap[BB];
-
- // Loop over all instructions, fixing each one as we find it...
- //
- for (BasicBlock::iterator II = NBB->begin(); II != NBB->end(); II++)
- RemapInstruction(*II, ValueMap);
- }
-
- if (PHI) RemapInstruction(PHI, ValueMap); // Fix the PHI node also...
-
- // Change the branch that used to go to NewBB to branch to the first basic
- // block of the inlined method.
- //
- TerminatorInst *Br = OrigBB->getTerminator();
- assert(Br && Br->getOpcode() == Instruction::Br &&
- "splitBasicBlock broken!");
- Br->setOperand(0, ValueMap[CalledMeth->front()]);
-
- // Since we are now done with the CallInst, we can finally delete it.
- delete CI;
- return true;
-}
-
-bool opt::InlineMethod(CallInst *CI) {
- assert(CI->getParent() && "CallInst not embeded in BasicBlock!");
- BasicBlock *PBB = CI->getParent();
-
- BasicBlock::iterator CallIt = find(PBB->begin(), PBB->end(), CI);
-
- assert(CallIt != PBB->end() &&
- "CallInst has parent that doesn't contain CallInst?!?");
- return InlineMethod(CallIt);
-}
-
-static inline bool ShouldInlineMethod(const CallInst *CI, const Method *M) {
- assert(CI->getParent() && CI->getParent()->getParent() &&
- "Call not embedded into a method!");
-
- // Don't inline a recursive call.
- if (CI->getParent()->getParent() == M) return false;
-
- // Don't inline something too big. This is a really crappy heuristic
- if (M->size() > 3) return false;
-
- // Don't inline into something too big. This is a **really** crappy heuristic
- if (CI->getParent()->getParent()->size() > 10) return false;
-
- // Go ahead and try just about anything else.
- return true;
-}
-
-
-static inline bool DoMethodInlining(BasicBlock *BB) {
- for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) {
- if ((*I)->getOpcode() == Instruction::Call) {
- // Check to see if we should inline this method
- CallInst *CI = (CallInst*)*I;
- Method *M = CI->getCalledMethod();
- if (ShouldInlineMethod(CI, M))
- return InlineMethod(I);
- }
+ // Insert into set of functions to never inline
+ if (const Function *F = dyn_cast<Function>(Elt))
+ NeverInline.insert(F);
}
+
return false;
}
-bool opt::DoMethodInlining(Method *M) {
- bool Changed = false;
-
- // Loop through now and inline instructions a basic block at a time...
- for (Method::iterator I = M->begin(); I != M->end(); )
- if (DoMethodInlining(*I)) {
- Changed = true;
- // Iterator is now invalidated by new basic blocks inserted
- I = M->begin();
- } else {
- ++I;
- }
-
- return Changed;
-}