lib/Transforms/IPO/InlineSimple.cpp

   1 //===- InlineSimple.cpp - Code to perform simple function inlining --------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements bottom-up inlining of functions into callees.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #define DEBUG_TYPE "inline"
  15 #include "llvm/CallingConv.h"
  16 #include "llvm/Instructions.h"
  17 #include "llvm/IntrinsicInst.h"
  18 #include "llvm/Module.h"
  19 #include "llvm/Type.h"
  20 #include "llvm/Analysis/CallGraph.h"
  21 #include "llvm/Support/CallSite.h"
  22 #include "llvm/Support/Compiler.h"
  23 #include "llvm/Transforms/IPO.h"
  24 #include "llvm/Transforms/IPO/InlinerPass.h"
  25 #include "llvm/Transforms/Utils/InlineCost.h"
  26 #include "llvm/ADT/SmallPtrSet.h"
  27
  28 using namespace llvm;
  29
  30 namespace {
  31
  32   class VISIBILITY_HIDDEN SimpleInliner : public Inliner {
  33     // Functions that are never inlined
  34     SmallPtrSet<const Function*, 16> NeverInline;
  35     InlineCostAnalyzer CA;
  36   public:
  37     SimpleInliner() : Inliner(&ID) {}
  38     SimpleInliner(int Threshold) : Inliner(&ID, Threshold) {}
  39     static char ID; // Pass identification, replacement for typeid
  40     InlineCost getInlineCost(CallSite CS) {
  41       return CA.getInlineCost(CS, NeverInline);
  42     }
  43     float getInlineFudgeFactor(CallSite CS) {
  44       return CA.getInlineFudgeFactor(CS);
  45     }
  46     void resetCachedCostInfo(Function *Caller) {
  47       CA.resetCachedCostInfo(Caller);
  48     }
  49     virtual bool doInitialization(CallGraph &CG);
  50   };
  51 }
  52
  53 char SimpleInliner::ID = 0;
  54 static RegisterPass<SimpleInliner>
  55 X("inline", "Function Integration/Inlining");
  56
  57 Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
  58
  59 Pass *llvm::createFunctionInliningPass(int Threshold) {
  60   return new SimpleInliner(Threshold);
  61 }
  62
  63 // doInitialization - Initializes the vector of functions that have been
  64 // annotated with the noinline attribute.
  65 bool SimpleInliner::doInitialization(CallGraph &CG) {
  66
  67   Module &M = CG.getModule();
  68
  69   for (Module::iterator I = M.begin(), E = M.end();
  70        I != E; ++I)
  71     if (!I->isDeclaration() && I->hasFnAttr(Attribute::NoInline))
  72       NeverInline.insert(I);
  73
  74   // Get llvm.noinline
  75   GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
  76
  77   if (GV == 0)
  78     return false;
  79
  80   // Don't crash on invalid code
  81   if (!GV->hasInitializer())
  82     return false;
  83
  84   const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
  85
  86   if (InitList == 0)
  87     return false;
  88
  89   // Iterate over each element and add to the NeverInline set
  90   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
  91
  92     // Get Source
  93     const Constant *Elt = InitList->getOperand(i);
  94
  95     if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
  96       if (CE->getOpcode() == Instruction::BitCast)
  97         Elt = CE->getOperand(0);
  98
  99     // Insert into set of functions to never inline
 100     if (const Function *F = dyn_cast<Function>(Elt))
 101       NeverInline.insert(F);
 102   }
 103
 104   return false;
 105 }
 106