[PlaceSafepoints] Switch to being a FunctionPass

The pass doesn't actually modify the module outside of the function being processed. The only confusing piece is that it both inserts calls and then inlines the resulting calls. Given that, it definitely invalidates module level analysis results, but many FunctionPasses do that.

Differential Revision: http://reviews.llvm.org/D9590

llvm-svn: 237185

llvm/include/llvm/Transforms/Scalar.h

@@ -442,7 +442,7 @@ FunctionPass *createStraightLineStrengthReducePass();
 // RewriteStatepointsForGC which can be run at an arbitrary point in the pass
 // order following this pass.
 //
-ModulePass *createPlaceSafepointsPass();
+FunctionPass *createPlaceSafepointsPass();
 
 //===----------------------------------------------------------------------===//
 //

llvm/lib/Transforms/Scalar/PlaceSafepoints.cpp

@@ -166,20 +166,13 @@ static cl::opt<bool> NoCall("spp-no-call", cl::Hidden, cl::init(false));
 static cl::opt<bool> NoBackedge("spp-no-backedge", cl::Hidden, cl::init(false));
 
 namespace {
-struct PlaceSafepoints : public ModulePass {
+struct PlaceSafepoints : public FunctionPass {
   static char ID; // Pass identification, replacement for typeid
 
-  PlaceSafepoints() : ModulePass(ID) {
+  PlaceSafepoints() : FunctionPass(ID) {
     initializePlaceSafepointsPass(*PassRegistry::getPassRegistry());
   }
-  bool runOnModule(Module &M) override {
-    bool modified = false;
-    for (Function &F : M) {
-      modified |= runOnFunction(F);
-    }
-    return modified;
-  }
-  bool runOnFunction(Function &F);
+  bool runOnFunction(Function &F) override;
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     // We modify the graph wholesale (inlining, block insertion, etc).  We
@@ -755,7 +748,9 @@ bool PlaceSafepoints::runOnFunction(Function &F) {
 char PlaceBackedgeSafepointsImpl::ID = 0;
 char PlaceSafepoints::ID = 0;
 
-ModulePass *llvm::createPlaceSafepointsPass() { return new PlaceSafepoints(); }
+FunctionPass *llvm::createPlaceSafepointsPass() {
+  return new PlaceSafepoints();
+}
 
 INITIALIZE_PASS_BEGIN(PlaceBackedgeSafepointsImpl,
                       "place-backedge-safepoints-impl",