1 files changed, 278 insertions, 0 deletions
diff --git a/lib/Transforms/IPO/Inliner.cpp b/lib/Transforms/IPO/Inliner.cpp
new file mode 100644
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+++ b/lib/Transforms/IPO/Inliner.cpp
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+//===- Inliner.cpp - Code common to all inliners --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the mechanics required to implement inlining without
+// missing any calls and updating the call graph.  The decisions of which calls
+// are profitable to inline are implemented elsewhere.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "inline"
+#include "llvm/Module.h"
+#include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/Analysis/CallGraph.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/IPO/InlinerPass.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/ADT/Statistic.h"
+#include <set>
+using namespace llvm;
+
+STATISTIC(NumInlined, "Number of functions inlined");
+STATISTIC(NumDeleted, "Number of functions deleted because all callers found");
+
+static cl::opt<int>
+InlineLimit("inline-threshold", cl::Hidden, cl::init(200),
+        cl::desc("Control the amount of inlining to perform (default = 200)"));
+
+Inliner::Inliner(void *ID) 
+  : CallGraphSCCPass(ID), InlineThreshold(InlineLimit) {}
+
+Inliner::Inliner(void *ID, int Threshold) 
+  : CallGraphSCCPass(ID), InlineThreshold(Threshold) {}
+
+/// getAnalysisUsage - For this class, we declare that we require and preserve
+/// the call graph.  If the derived class implements this method, it should
+/// always explicitly call the implementation here.
+void Inliner::getAnalysisUsage(AnalysisUsage &Info) const {
+  Info.addRequired<TargetData>();
+  CallGraphSCCPass::getAnalysisUsage(Info);
+}
+
+// InlineCallIfPossible - If it is possible to inline the specified call site,
+// do so and update the CallGraph for this operation.
+bool Inliner::InlineCallIfPossible(CallSite CS, CallGraph &CG,
+                                 const SmallPtrSet<Function*, 8> &SCCFunctions,
+                                 const TargetData &TD) {
+  Function *Callee = CS.getCalledFunction();
+  Function *Caller = CS.getCaller();
+
+  if (!InlineFunction(CS, &CG, &TD)) return false;
+
+  // If the inlined function had a higher stack protection level than the
+  // calling function, then bump up the caller's stack protection level.
+  if (Callee->hasFnAttr(Attribute::StackProtectReq))
+    Caller->addFnAttr(Attribute::StackProtectReq);
+  else if (Callee->hasFnAttr(Attribute::StackProtect) &&
+           !Caller->hasFnAttr(Attribute::StackProtectReq))
+    Caller->addFnAttr(Attribute::StackProtect);
+
+  // If we inlined the last possible call site to the function, delete the
+  // function body now.
+  if (Callee->use_empty() && (Callee->hasLocalLinkage() ||
+                              Callee->hasAvailableExternallyLinkage()) &&
+      !SCCFunctions.count(Callee)) {
+    DOUT << "    -> Deleting dead function: " << Callee->getName() << "\n";
+    CallGraphNode *CalleeNode = CG[Callee];
+
+    // Remove any call graph edges from the callee to its callees.
+    CalleeNode->removeAllCalledFunctions();
+
+    resetCachedCostInfo(CalleeNode->getFunction());
+
+    // Removing the node for callee from the call graph and delete it.
+    delete CG.removeFunctionFromModule(CalleeNode);
+    ++NumDeleted;
+  }
+  return true;
+}
+        
+/// shouldInline - Return true if the inliner should attempt to inline
+/// at the given CallSite.
+bool Inliner::shouldInline(CallSite CS) {
+  InlineCost IC = getInlineCost(CS);
+  float FudgeFactor = getInlineFudgeFactor(CS);
+  
+  if (IC.isAlways()) {
+    DOUT << "    Inlining: cost=always"
+         << ", Call: " << *CS.getInstruction();
+    return true;
+  }
+  
+  if (IC.isNever()) {
+    DOUT << "    NOT Inlining: cost=never"
+         << ", Call: " << *CS.getInstruction();
+    return false;
+  }
+  
+  int Cost = IC.getValue();
+  int CurrentThreshold = InlineThreshold;
+  Function *Fn = CS.getCaller();
+  if (Fn && !Fn->isDeclaration() 
+      && Fn->hasFnAttr(Attribute::OptimizeForSize)
+      && InlineThreshold != 50) {
+    CurrentThreshold = 50;
+  }
+  
+  if (Cost >= (int)(CurrentThreshold * FudgeFactor)) {
+    DOUT << "    NOT Inlining: cost=" << Cost
+         << ", Call: " << *CS.getInstruction();
+    return false;
+  } else {
+    DOUT << "    Inlining: cost=" << Cost
+         << ", Call: " << *CS.getInstruction();
+    return true;
+  }
+}
+
+bool Inliner::runOnSCC(const std::vector<CallGraphNode*> &SCC) {
+  CallGraph &CG = getAnalysis<CallGraph>();
+  TargetData &TD = getAnalysis<TargetData>();
+
+  SmallPtrSet<Function*, 8> SCCFunctions;
+  DOUT << "Inliner visiting SCC:";
+  for (unsigned i = 0, e = SCC.size(); i != e; ++i) {
+    Function *F = SCC[i]->getFunction();
+    if (F) SCCFunctions.insert(F);
+    DOUT << " " << (F ? F->getName() : "INDIRECTNODE");
+  }
+
+  // Scan through and identify all call sites ahead of time so that we only
+  // inline call sites in the original functions, not call sites that result
+  // from inlining other functions.
+  std::vector<CallSite> CallSites;
+
+  for (unsigned i = 0, e = SCC.size(); i != e; ++i)
+    if (Function *F = SCC[i]->getFunction())
+      for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
+        for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) {
+          CallSite CS = CallSite::get(I);
+          if (CS.getInstruction() && !isa<DbgInfoIntrinsic>(I) &&
+                                     (!CS.getCalledFunction() ||
+                                      !CS.getCalledFunction()->isDeclaration()))
+            CallSites.push_back(CS);
+        }
+
+  DOUT << ": " << CallSites.size() << " call sites.\n";
+
+  // Now that we have all of the call sites, move the ones to functions in the
+  // current SCC to the end of the list.
+  unsigned FirstCallInSCC = CallSites.size();
+  for (unsigned i = 0; i < FirstCallInSCC; ++i)
+    if (Function *F = CallSites[i].getCalledFunction())
+      if (SCCFunctions.count(F))
+        std::swap(CallSites[i--], CallSites[--FirstCallInSCC]);
+
+  // Now that we have all of the call sites, loop over them and inline them if
+  // it looks profitable to do so.
+  bool Changed = false;
+  bool LocalChange;
+  do {
+    LocalChange = false;
+    // Iterate over the outer loop because inlining functions can cause indirect
+    // calls to become direct calls.
+    for (unsigned CSi = 0; CSi != CallSites.size(); ++CSi)
+      if (Function *Callee = CallSites[CSi].getCalledFunction()) {
+        // Calls to external functions are never inlinable.
+        if (Callee->isDeclaration()) {
+          if (SCC.size() == 1) {
+            std::swap(CallSites[CSi], CallSites.back());
+            CallSites.pop_back();
+          } else {
+            // Keep the 'in SCC / not in SCC' boundary correct.
+            CallSites.erase(CallSites.begin()+CSi);
+          }
+          --CSi;
+          continue;
+        }
+
+        // If the policy determines that we should inline this function,
+        // try to do so.
+        CallSite CS = CallSites[CSi];
+        if (shouldInline(CS)) {
+          Function *Caller = CS.getCaller();
+          // Attempt to inline the function...
+          if (InlineCallIfPossible(CS, CG, SCCFunctions, TD)) {
+            // Remove any cached cost info for this caller, as inlining the
+            // callee has increased the size of the caller (which may be the
+            // same as the callee).
+            resetCachedCostInfo(Caller);
+
+            // Remove this call site from the list.  If possible, use 
+            // swap/pop_back for efficiency, but do not use it if doing so would
+            // move a call site to a function in this SCC before the
+            // 'FirstCallInSCC' barrier.
+            if (SCC.size() == 1) {
+              std::swap(CallSites[CSi], CallSites.back());
+              CallSites.pop_back();
+            } else {
+              CallSites.erase(CallSites.begin()+CSi);
+            }
+            --CSi;
+
+            ++NumInlined;
+            Changed = true;
+            LocalChange = true;
+          }
+        }
+      }
+  } while (LocalChange);
+
+  return Changed;
+}
+
+// doFinalization - Remove now-dead linkonce functions at the end of
+// processing to avoid breaking the SCC traversal.
+bool Inliner::doFinalization(CallGraph &CG) {
+  return removeDeadFunctions(CG);
+}
+
+  /// removeDeadFunctions - Remove dead functions that are not included in
+  /// DNR (Do Not Remove) list.
+bool Inliner::removeDeadFunctions(CallGraph &CG, 
+                                 SmallPtrSet<const Function *, 16> *DNR) {
+  std::set<CallGraphNode*> FunctionsToRemove;
+
+  // Scan for all of the functions, looking for ones that should now be removed
+  // from the program.  Insert the dead ones in the FunctionsToRemove set.
+  for (CallGraph::iterator I = CG.begin(), E = CG.end(); I != E; ++I) {
+    CallGraphNode *CGN = I->second;
+    if (Function *F = CGN ? CGN->getFunction() : 0) {
+      // If the only remaining users of the function are dead constants, remove
+      // them.
+      F->removeDeadConstantUsers();
+
+      if (DNR && DNR->count(F))
+        continue;
+
+      if ((F->hasLinkOnceLinkage() || F->hasLocalLinkage()) &&
+          F->use_empty()) {
+
+        // Remove any call graph edges from the function to its callees.
+        CGN->removeAllCalledFunctions();
+
+        // Remove any edges from the external node to the function's call graph
+        // node.  These edges might have been made irrelegant due to
+        // optimization of the program.
+        CG.getExternalCallingNode()->removeAnyCallEdgeTo(CGN);
+
+        // Removing the node for callee from the call graph and delete it.
+        FunctionsToRemove.insert(CGN);
+      }
+    }
+  }
+
+  // Now that we know which functions to delete, do so.  We didn't want to do
+  // this inline, because that would invalidate our CallGraph::iterator
+  // objects. :(
+  bool Changed = false;
+  for (std::set<CallGraphNode*>::iterator I = FunctionsToRemove.begin(),
+         E = FunctionsToRemove.end(); I != E; ++I) {
+    resetCachedCostInfo((*I)->getFunction());
+    delete CG.removeFunctionFromModule(*I);
+    ++NumDeleted;
+    Changed = true;
+  }
+
+  return Changed;
+}