Remove the "really gross hacks" that are there to deal with recursive functions.

Now we collect all of the call sites we are interested in inlining, then inline
them.  This entirely avoids issues with trying to inline a call site we got by
inlining another call site.  This also eliminates iterator invalidation issues.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12770 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 54 insertions, 71 deletions

diff --git a/lib/Transforms/IPO/Inliner.cpp b/lib/Transforms/IPO/Inliner.cpp
index c0861f1b67..325631a792 100644
--- a/lib/Transforms/IPO/Inliner.cpp
+++ b/lib/Transforms/IPO/Inliner.cpp
@@ -58,84 +58,67 @@ bool Inliner::runOnSCC(const std::vector<CallGraphNode*> &SCC) {
     if (F == 0 || F->isExternal()) continue;
     DEBUG(std::cerr << "  Inspecting function: " << F->getName() << "\n");
 
+    // 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
+    // in inlining other functions.
+    std::vector<CallSite> CallSites;
     for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
-      for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
-        bool ShouldInc = true;
-        // Found a call or invoke instruction?
-        if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
-          CallSite CS = CallSite::get(I);
-          if (Function *Callee = CS.getCalledFunction())
-            if (!Callee->isExternal() && !IsRecursiveFunction.count(Callee)) {
-              // Determine whether this is a function IN the SCC...
-              bool inSCC = SCCFunctions.count(Callee);
+      for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) {
+        CallSite CS = CallSite::get(I);
+        if (CS.getInstruction() && CS.getCalledFunction() &&
+            !CS.getCalledFunction()->isExternal())
+          CallSites.push_back(CS);
+      }
 
-              // Keep track of whether this is a directly recursive function.
-              if (Callee == F) IsRecursiveFunction.insert(F);
+    // Now that we have all of the call sites, loop over them and inline them if
+    // it looks profitable to do so.
+    for (unsigned i = 0, e = CallSites.size(); i != e; ++i) {
+      CallSite CS = CallSites[i];
+      Function *Callee = CS.getCalledFunction();
+      // Determine whether this is a function IN the SCC...
+      bool inSCC = SCCFunctions.count(Callee);
+    
+      // If the policy determines that we should inline this function,
+      // try to do so...
+      int InlineCost = inSCC ? getRecursiveInlineCost(CS) : getInlineCost(CS);
+      if (InlineCost >= (int)InlineThreshold) {
+        DEBUG(std::cerr << "    NOT Inlining: cost=" << InlineCost
+              << ", Call: " << *CS.getInstruction());
+      } else {
+        DEBUG(std::cerr << "    Inlining: cost=" << InlineCost
+              << ", Call: " << *CS.getInstruction());
+      
+        Function *Caller = CS.getInstruction()->getParent()->getParent();
 
-              // If the policy determines that we should inline this function,
-              // try to do so...
-              int InlineCost = inSCC ? getRecursiveInlineCost(CS) :
-                                       getInlineCost(CS);
-              if (InlineCost >= (int)InlineThreshold) {
-                DEBUG(std::cerr << "    NOT Inlining: cost=" << InlineCost
-                                << ", Call: " << *CS.getInstruction());
-              } else {
-                DEBUG(std::cerr << "    Inlining: cost=" << InlineCost
-                                << ", Call: " << *CS.getInstruction());
+        // Attempt to inline the function...
+        if (InlineFunction(CS)) {
+          ++NumInlined;
+  
+          if (Callee->hasOneUse())
+            if (ConstantPointerRef *CPR =
+                dyn_cast<ConstantPointerRef>(Callee->use_back()))
+              if (CPR->use_empty())
+                CPR->destroyConstant();
+        
+          // If we inlined the last possible call site to the function,
+          // delete the function body now.
+          if (Callee->use_empty() && Callee != Caller &&
+              (Callee->hasInternalLinkage() || Callee->hasLinkOnceLinkage())) {
+            DEBUG(std::cerr << "    -> Deleting dead function: "
+                  << (void*)Callee << Callee->getName() << "\n");
+            std::set<Function*>::iterator I = SCCFunctions.find(Callee);
+            if (I != SCCFunctions.end())    // Remove function from this SCC.
+              SCCFunctions.erase(I);
 
-                // Save an iterator to the instruction before the call if it
-                // exists, otherwise get an iterator at the end of the
-                // block... because the call will be destroyed.
-                //
-                BasicBlock::iterator SI;
-                if (I != BB->begin()) {
-                  SI = I; --SI;           // Instruction before the call...
-                } else {
-                  SI = BB->end();
-                }
-                
-                if (performInlining(CS, SCCFunctions)) {
-                  // Move to instruction before the call...
-                  I = (SI == BB->end()) ? BB->begin() : SI;
-                  ShouldInc = false; // Don't increment iterator until next time
-                  Changed = true;
-                }
-              }
-            }
+            Callee->getParent()->getFunctionList().erase(Callee);
+            ++NumDeleted;
+          }
+          Changed = true;
         }
-        if (ShouldInc) ++I;
       }
+    }
   }
-  return Changed;
-}
-
-bool Inliner::performInlining(CallSite CS, std::set<Function*> &SCC) {
-  Function *Callee = CS.getCalledFunction();
-  Function *Caller = CS.getInstruction()->getParent()->getParent();
 
-  // Attempt to inline the function...
-  if (!InlineFunction(CS)) return false;
-  ++NumInlined;
-  
-  if (Callee->hasOneUse())
-    if (ConstantPointerRef *CPR =
-        dyn_cast<ConstantPointerRef>(Callee->use_back()))
-      if (CPR->use_empty())
-        CPR->destroyConstant();
-  
-  // If we inlined the last possible call site to the function,
-  // delete the function body now.
-  if (Callee->use_empty() && Callee != Caller &&
-      (Callee->hasInternalLinkage() || Callee->hasLinkOnceLinkage())) {
-    DEBUG(std::cerr << "    -> Deleting dead function: " << (void*)Callee
-                    << Callee->getName() << "\n");
-    std::set<Function*>::iterator I = SCC.find(Callee);
-    if (I != SCC.end())       // Remove function from this SCC...
-      SCC.erase(I);
-
-    Callee->getParent()->getFunctionList().erase(Callee);
-    ++NumDeleted;
-  }
-  return true; 
+  return Changed;
 }