Add InlineCost class for represent the estimated cost of inlining a

[oota-llvm.git] / lib / Transforms / Utils / InlineCost.cpp

diff --git a/lib/Transforms/Utils/InlineCost.cpp b/lib/Transforms/Utils/InlineCost.cpp
index c17705bf85090504a74bfe0681d1d839e1791a63..b85a45590cb60230979332707ef3390ed9ae40b7 100644 (file)
--- a/lib/Transforms/Utils/InlineCost.cpp
+++ b/lib/Transforms/Utils/InlineCost.cpp
@@ -100,9 +100,32 @@ void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F) {
   for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB) {
     for (BasicBlock::const_iterator II = BB->begin(), E = BB->end();
          II != E; ++II) {
-      if (isa<DbgInfoIntrinsic>(II)) continue;  // Debug intrinsics don't count.
       if (isa<PHINode>(II)) continue;           // PHI nodes don't count.
 
+      // Special handling for calls.
+      if (isa<CallInst>(II) || isa<InvokeInst>(II)) {
+        if (isa<DbgInfoIntrinsic>(II))
+          continue;  // Debug intrinsics don't count as size.
+        
+        CallSite CS = CallSite::get(const_cast<Instruction*>(&*II));
+        
+        // If this function contains a call to setjmp or _setjmp, never inline
+        // it.  This is a hack because we depend on the user marking their local
+        // variables as volatile if they are live across a setjmp call, and they
+        // probably won't do this in callers.
+        if (Function *F = CS.getCalledFunction())
+          if (F->isDeclaration() && 
+              (F->isName("setjmp") || F->isName("_setjmp"))) {
+            NeverInline = true;
+            return;
+          }
+        
+        // Calls often compile into many machine instructions.  Bump up their
+        // cost to reflect this.
+        if (!isa<IntrinsicInst>(II))
+          NumInsts += 5;
+      }
+      
       if (isa<ExtractElementInst>(II) || isa<VectorType>(II->getType()))
         ++NumVectorInsts; 
       
@@ -146,22 +169,26 @@ void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F) {
 // getInlineCost - The heuristic used to determine if we should inline the
 // function call or not.
 //
-int InlineCostAnalyzer::getInlineCost(CallSite CS,
+InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS,
                                SmallPtrSet<const Function *, 16> &NeverInline) {
   Instruction *TheCall = CS.getInstruction();
   Function *Callee = CS.getCalledFunction();
   const Function *Caller = TheCall->getParent()->getParent();
-  
+
   // Don't inline a directly recursive call.
   if (Caller == Callee ||
       // Don't inline functions which can be redefined at link-time to mean
-      // something else.  link-once linkage is ok though.
-      Callee->hasWeakLinkage() ||
-      
+      // something else.
+      // FIXME: We allow link-once linkage since in practice all versions of
+      // the function have the same body (C++ ODR) - but the LLVM definition
+      // of LinkOnceLinkage doesn't require this.
+      (Callee->mayBeOverridden() && !Callee->hasLinkOnceLinkage()
+       ) ||
+
       // Don't inline functions marked noinline.
       NeverInline.count(Callee))
-    return 2000000000;
-  
+    return llvm::InlineCost::getNever();
+
   // InlineCost - This value measures how good of an inline candidate this call
   // site is to inline.  A lower inline cost make is more likely for the call to
   // be inlined.  This value may go negative.
@@ -194,6 +221,17 @@ int InlineCostAnalyzer::getInlineCost(CallSite CS,
   // If we haven't calculated this information yet, do so now.
   if (CalleeFI.NumBlocks == 0)
     CalleeFI.analyzeFunction(Callee);
+  
+  // If we should never inline this, return a huge cost.
+  if (CalleeFI.NeverInline)
+    return InlineCost::getNever();
+
+  // FIXME: It would be nice to kill off CalleeFI.NeverInline. Then we
+  // could move this up and avoid computing the FunctionInfo for
+  // things we are going to just return always inline for. This
+  // requires handling setjmp somewhere else, however.
+  if (!Callee->isDeclaration() && Callee->hasFnAttr(Attribute::AlwaysInline))
+    return InlineCost::getAlways();
     
   // Add to the inline quality for properties that make the call valuable to
   // inline.  This includes factors that indicate that the result of inlining
@@ -240,7 +278,7 @@ int InlineCostAnalyzer::getInlineCost(CallSite CS,
   // Look at the size of the callee. Each instruction counts as 5.
   InlineCost += CalleeFI.NumInsts*5;
 
-  return InlineCost;
+  return llvm::InlineCost::get(InlineCost);
 }
 
 // getInlineFudgeFactor - Return a > 1.0 factor if the inliner should use a