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/Analysis/InlineCost.h"
  22 #include "llvm/Support/CallSite.h"
  23 #include "llvm/Transforms/IPO.h"
  24 #include "llvm/Transforms/IPO/InlinerPass.h"
  25 #include "llvm/ADT/SmallPtrSet.h"
  26
  27 using namespace llvm;
  28
  29 namespace {
  30
  31   class SimpleInliner : public Inliner {
  32     // Functions that are never inlined
  33     SmallPtrSet<const Function*, 16> NeverInline;
  34     InlineCostAnalyzer CA;
  35   public:
  36     SimpleInliner() : Inliner(ID) {
  37       initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
  38     }
  39     SimpleInliner(int Threshold) : Inliner(ID, Threshold) {
  40       initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
  41     }
  42     static char ID; // Pass identification, replacement for typeid
  43     InlineCost getInlineCost(CallSite CS) {
  44       return CA.getInlineCost(CS, NeverInline);
  45     }
  46     float getInlineFudgeFactor(CallSite CS) {
  47       return CA.getInlineFudgeFactor(CS);
  48     }
  49     void resetCachedCostInfo(Function *Caller) {
  50       CA.resetCachedCostInfo(Caller);
  51     }
  52     void growCachedCostInfo(Function* Caller, Function* Callee) {
  53       CA.growCachedCostInfo(Caller, Callee);
  54     }
  55     virtual bool doInitialization(CallGraph &CG);
  56     void releaseMemory() {
  57       CA.clear();
  58     }
  59   };
  60 }
  61
  62 char SimpleInliner::ID = 0;
  63 INITIALIZE_PASS_BEGIN(SimpleInliner, "inline",
  64                 "Function Integration/Inlining", false, false)
  65 INITIALIZE_AG_DEPENDENCY(CallGraph)
  66 INITIALIZE_PASS_END(SimpleInliner, "inline",
  67                 "Function Integration/Inlining", false, false)
  68
  69 Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
  70
  71 Pass *llvm::createFunctionInliningPass(int Threshold) {
  72   return new SimpleInliner(Threshold);
  73 }
  74
  75 // doInitialization - Initializes the vector of functions that have been
  76 // annotated with the noinline attribute.
  77 bool SimpleInliner::doInitialization(CallGraph &CG) {
  78
  79   Module &M = CG.getModule();
  80
  81   for (Module::iterator I = M.begin(), E = M.end();
  82        I != E; ++I)
  83     if (!I->isDeclaration() && I->hasFnAttr(Attribute::NoInline))
  84       NeverInline.insert(I);
  85
  86   // Get llvm.noinline
  87   GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
  88
  89   if (GV == 0)
  90     return false;
  91
  92   // Don't crash on invalid code
  93   if (!GV->hasDefinitiveInitializer())
  94     return false;
  95
  96   const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
  97
  98   if (InitList == 0)
  99     return false;
 100
 101   // Iterate over each element and add to the NeverInline set
 102   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
 103
 104     // Get Source
 105     const Constant *Elt = InitList->getOperand(i);
 106
 107     if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
 108       if (CE->getOpcode() == Instruction::BitCast)
 109         Elt = CE->getOperand(0);
 110
 111     // Insert into set of functions to never inline
 112     if (const Function *F = dyn_cast<Function>(Elt))
 113       NeverInline.insert(F);
 114   }
 115
 116   return false;
 117 }
 118