1 files changed, 217 insertions, 0 deletions
diff --git a/lib/Transforms/IPO/Inliner.cpp b/lib/Transforms/IPO/Inliner.cpp
new file mode 100644
index 0000000..85893d7
--- /dev/null
+++ b/lib/Transforms/IPO/Inliner.cpp
@@ -0,0 +1,217 @@
+//===- Inliner.cpp - Code common to all inliners --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and 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/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");
+
+namespace {
+  cl::opt<unsigned>             // FIXME: 200 is VERY conservative
+  InlineLimit("inline-threshold", cl::Hidden, cl::init(200),
+        cl::desc("Control the amount of inlining to perform (default = 200)"));
+}
+
+Inliner::Inliner(const void *ID) 
+  : CallGraphSCCPass((intptr_t)ID), InlineThreshold(InlineLimit) {}
+
+/// 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.
+static bool InlineCallIfPossible(CallSite CS, CallGraph &CG,
+                                 const std::set<Function*> &SCCFunctions,
+                                 const TargetData &TD) {
+  Function *Callee = CS.getCalledFunction();
+  if (!InlineFunction(CS, &CG, &TD)) return false;
+
+  // If we inlined the last possible call site to the function, delete the
+  // function body now.
+  if (Callee->use_empty() && Callee->hasInternalLinkage() &&
+      !SCCFunctions.count(Callee)) {
+    DOUT << "    -> Deleting dead function: " << Callee->getName() << "\n";
+
+    // Remove any call graph edges from the callee to its callees.
+    CallGraphNode *CalleeNode = CG[Callee];
+    while (CalleeNode->begin() != CalleeNode->end())
+      CalleeNode->removeCallEdgeTo((CalleeNode->end()-1)->second);
+
+    // Removing the node for callee from the call graph and delete it.
+    delete CG.removeFunctionFromModule(CalleeNode);
+    ++NumDeleted;
+  }
+  return true;
+}
+
+bool Inliner::runOnSCC(const std::vector<CallGraphNode*> &SCC) {
+  CallGraph &CG = getAnalysis<CallGraph>();
+
+  std::set<Function*> 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() && (!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() ||
+            CallSites[CSi].getInstruction()->getParent()->getParent() ==Callee){
+          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];
+        int InlineCost = getInlineCost(CS);
+        if (InlineCost >= (int)InlineThreshold) {
+          DOUT << "    NOT Inlining: cost=" << InlineCost
+               << ", Call: " << *CS.getInstruction();
+        } else {
+          DOUT << "    Inlining: cost=" << InlineCost
+               << ", Call: " << *CS.getInstruction();
+
+          // Attempt to inline the function...
+          if (InlineCallIfPossible(CS, CG, SCCFunctions, 
+                                   getAnalysis<TargetData>())) {
+            // 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) {
+  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 ((F->hasLinkOnceLinkage() || F->hasInternalLinkage()) &&
+          F->use_empty()) {
+
+        // Remove any call graph edges from the function to its callees.
+        while (CGN->begin() != CGN->end())
+          CGN->removeCallEdgeTo((CGN->end()-1)->second);
+
+        // 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) {
+    delete CG.removeFunctionFromModule(*I);
+    ++NumDeleted;
+    Changed = true;
+  }
+
+  return Changed;
+}