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