lib/Transforms/IPO/InlineAlways.cpp

   1 //===- InlineAlways.cpp - Code to inline always_inline functions ----------===//
   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 a custom inliner that handles only functions that
  11 // are marked as "always inline".
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #define DEBUG_TYPE "inline"
  16 #include "llvm/CallingConv.h"
  17 #include "llvm/Instructions.h"
  18 #include "llvm/IntrinsicInst.h"
  19 #include "llvm/Module.h"
  20 #include "llvm/Type.h"
  21 #include "llvm/Analysis/CallGraph.h"
  22 #include "llvm/Support/CallSite.h"
  23 #include "llvm/Support/Compiler.h"
  24 #include "llvm/Transforms/IPO.h"
  25 #include "llvm/Transforms/IPO/InlinerPass.h"
  26 #include "llvm/Transforms/Utils/InlineCost.h"
  27 #include "llvm/ADT/SmallPtrSet.h"
  28
  29 using namespace llvm;
  30
  31 namespace {
  32
  33   // AlwaysInliner only inlines functions that are mark as "always inline".
  34   class VISIBILITY_HIDDEN AlwaysInliner : public Inliner {
  35     // Functions that are never inlined
  36     SmallPtrSet<const Function*, 16> NeverInline;
  37     InlineCostAnalyzer CA;
  38   public:
  39     // Use extremely low threshold.
  40     AlwaysInliner() : Inliner(&ID, -2000000000) {}
  41     static char ID; // Pass identification, replacement for typeid
  42     InlineCost getInlineCost(CallSite CS) {
  43       return CA.getInlineCost(CS, NeverInline);
  44     }
  45     float getInlineFudgeFactor(CallSite CS) {
  46       return CA.getInlineFudgeFactor(CS);
  47     }
  48     void resetCachedCostInfo(Function *Caller) {
  49       return CA.resetCachedCostInfo(Caller);
  50     }
  51     virtual bool doFinalization(CallGraph &CG) {
  52       return removeDeadFunctions(CG, &NeverInline);
  53     }
  54     virtual bool doInitialization(CallGraph &CG);
  55   };
  56 }
  57
  58 char AlwaysInliner::ID = 0;
  59 static RegisterPass<AlwaysInliner>
  60 X("always-inline", "Inliner for always_inline functions");
  61
  62 Pass *llvm::createAlwaysInlinerPass() { return new AlwaysInliner(); }
  63
  64 // doInitialization - Initializes the vector of functions that have not
  65 // been annotated with the "always inline" attribute.
  66 bool AlwaysInliner::doInitialization(CallGraph &CG) {
  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::AlwaysInline))
  72       NeverInline.insert(I);
  73
  74   return false;
  75 }