Refactor inline costs analysis by removing the InlineCostAnalysis class

[oota-llvm.git] / lib / Transforms / IPO / InlineAlways.cpp

diff --git a/lib/Transforms/IPO/InlineAlways.cpp b/lib/Transforms/IPO/InlineAlways.cpp
index 448f2461411b134b729b6c693aa5e6d93f0ed0e7..1704bfea0b86a64b205ad65c68706e9aba455d4d 100644 (file)
--- a/lib/Transforms/IPO/InlineAlways.cpp
+++ b/lib/Transforms/IPO/InlineAlways.cpp
@@ -12,60 +12,89 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "inline"
-#include "llvm/CallingConv.h"
-#include "llvm/Instructions.h"
-#include "llvm/IntrinsicInst.h"
-#include "llvm/Module.h"
-#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"
+#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/CallGraph.h"
+#include "llvm/Analysis/InlineCost.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/IR/CallSite.h"
+#include "llvm/IR/CallingConv.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Transforms/IPO/InlinerPass.h"
 
 using namespace llvm;
 
+#define DEBUG_TYPE "inline"
+
 namespace {
 
-  // AlwaysInliner only inlines functions that are mark as "always inline".
-  class VISIBILITY_HIDDEN AlwaysInliner : public Inliner {
-    // Functions that are never inlined
-    SmallPtrSet<const Function*, 16> NeverInline; 
-    InlineCostAnalyzer CA;
-  public:
-    // Use extremely low threshold. 
-    AlwaysInliner() : Inliner(&ID, -2000000000) {}
-    static char ID; // Pass identification, replacement for typeid
-    int getInlineCost(CallSite CS) {
-      return CA.getInlineCost(CS, NeverInline);
-    }
-    float getInlineFudgeFactor(CallSite CS) {
-      return CA.getInlineFudgeFactor(CS);
-    }
-    virtual bool doInitialization(CallGraph &CG);
-  };
+/// \brief Inliner pass which only handles "always inline" functions.
+class AlwaysInliner : public Inliner {
+
+public:
+  // Use extremely low threshold.
+  AlwaysInliner() : Inliner(ID, -2000000000, /*InsertLifetime*/ true) {
+    initializeAlwaysInlinerPass(*PassRegistry::getPassRegistry());
+  }
+
+  AlwaysInliner(bool InsertLifetime)
+      : Inliner(ID, -2000000000, InsertLifetime) {
+    initializeAlwaysInlinerPass(*PassRegistry::getPassRegistry());
+  }
+
+  static char ID; // Pass identification, replacement for typeid
+
+  InlineCost getInlineCost(CallSite CS) override;
+
+  using llvm::Pass::doFinalization;
+  bool doFinalization(CallGraph &CG) override {
+    return removeDeadFunctions(CG, /*AlwaysInlineOnly=*/ true);
+  }
+};
+
 }
 
 char AlwaysInliner::ID = 0;
-static RegisterPass<AlwaysInliner>
-X("always-inline", "Inliner that handles always_inline functions");
+INITIALIZE_PASS_BEGIN(AlwaysInliner, "always-inline",
+                "Inliner for always_inline functions", false, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
+INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
+INITIALIZE_PASS_END(AlwaysInliner, "always-inline",
+                "Inliner for always_inline functions", false, false)
 
 Pass *llvm::createAlwaysInlinerPass() { return new AlwaysInliner(); }
 
-// doInitialization - Initializes the vector of functions that have not 
-// been annotated with the "always inline" attribute.
-bool AlwaysInliner::doInitialization(CallGraph &CG) {
-  
-  Module &M = CG.getModule();
-  
-  for (Module::iterator I = M.begin(), E = M.end();
-       I != E; ++I)
-    if (!I->isDeclaration() && !I->hasNote(Attribute::AlwaysInline))
-      NeverInline.insert(I);
-
-  return false;
+Pass *llvm::createAlwaysInlinerPass(bool InsertLifetime) {
+  return new AlwaysInliner(InsertLifetime);
 }
 
+/// \brief Get the inline cost for the always-inliner.
+///
+/// The always inliner *only* handles functions which are marked with the
+/// attribute to force inlining. As such, it is dramatically simpler and avoids
+/// using the powerful (but expensive) inline cost analysis. Instead it uses
+/// a very simple and boring direct walk of the instructions looking for
+/// impossible-to-inline constructs.
+///
+/// Note, it would be possible to go to some lengths to cache the information
+/// computed here, but as we only expect to do this for relatively few and
+/// small functions which have the explicit attribute to force inlining, it is
+/// likely not worth it in practice.
+InlineCost AlwaysInliner::getInlineCost(CallSite CS) {
+  Function *Callee = CS.getCalledFunction();
+
+  // Only inline direct calls to functions with always-inline attributes
+  // that are viable for inlining. FIXME: We shouldn't even get here for
+  // declarations.
+  if (Callee && !Callee->isDeclaration() &&
+      CS.hasFnAttr(Attribute::AlwaysInline) && isInlineViable(*Callee))
+    return InlineCost::getAlways();
+
+  return InlineCost::getNever();
+}