[ARM] Pass a callback to FunctionPass constructors to enable skipping execution

on a per-function basis.

Previously some of the passes were conditionally added to ARM's pass pipeline
based on the target machine's subtarget. This patch makes changes to add those
passes unconditionally and execute them conditonally based on the predicate
functor passed to the pass constructors. This enables running different sets of
passes for different functions in the module.

rdar://problem/20542263

Differential Revision: http://reviews.llvm.org/D8717


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239325 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/MachineInstrBundle.cpp

@@ -23,11 +23,15 @@ namespace {
   class UnpackMachineBundles : public MachineFunctionPass {
   public:
     static char ID; // Pass identification
-    UnpackMachineBundles() : MachineFunctionPass(ID) {
+    UnpackMachineBundles(std::function<bool(const Function &)> Ftor = nullptr)
+        : MachineFunctionPass(ID), PredicateFtor(Ftor) {
       initializeUnpackMachineBundlesPass(*PassRegistry::getPassRegistry());
     }
 
     bool runOnMachineFunction(MachineFunction &MF) override;
+
+  private:
+    std::function<bool(const Function &)> PredicateFtor;
   };
 } // end anonymous namespace
 
@@ -37,6 +41,9 @@ INITIALIZE_PASS(UnpackMachineBundles, "unpack-mi-bundles",
                 "Unpack machine instruction bundles", false, false)
 
 bool UnpackMachineBundles::runOnMachineFunction(MachineFunction &MF) {
+  if (PredicateFtor && !PredicateFtor(*MF.getFunction()))
+    return false;
+
   bool Changed = false;
   for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
     MachineBasicBlock *MBB = &*I;
@@ -69,6 +76,10 @@ bool UnpackMachineBundles::runOnMachineFunction(MachineFunction &MF) {
   return Changed;
 }
 
+FunctionPass *
+llvm::createUnpackMachineBundles(std::function<bool(const Function &)> Ftor) {
+  return new UnpackMachineBundles(Ftor);
+}
 
 namespace {
   class FinalizeMachineBundles : public MachineFunctionPass {