[GlobalISel] Localizer: Allow targets not to run the pass conditionally

Summary:
Previously, it was not possible to skip running the localizer pass
conditionally. This patch adds an input function to the pass which
decides if the pass should run on the given MachineFunction or not.

No test case as there is no upstream target needs this functionality.

Reviewers: qcolombet

Reviewed By: qcolombet

Subscribers: rovka, hiraditya, Petar.Avramovic, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71038

llvm/include/llvm/CodeGen/GlobalISel/Localizer.h

@@ -42,6 +42,10 @@ public:
   static char ID;
 
 private:
+  /// An input function to decide if the pass should run or not
+  /// on the given MachineFunction.
+  std::function<bool(const MachineFunction &)> DoNotRunPass;
+
   /// MRI contains all the register class/bank information that this
   /// pass uses and updates.
   MachineRegisterInfo *MRI;
@@ -72,6 +76,7 @@ private:
 
 public:
   Localizer();
+  Localizer(std::function<bool(const MachineFunction &)>);
 
   StringRef getPassName() const override { return "Localizer"; }
 

llvm/lib/CodeGen/GlobalISel/Localizer.cpp

@@ -29,7 +29,11 @@ INITIALIZE_PASS_END(Localizer, DEBUG_TYPE,
                     "Move/duplicate certain instructions close to their use",
                     false, false)
 
-Localizer::Localizer() : MachineFunctionPass(ID) { }
+Localizer::Localizer(std::function<bool(const MachineFunction &)> F)
+    : MachineFunctionPass(ID), DoNotRunPass(F) {}
+
+Localizer::Localizer()
+    : Localizer([](const MachineFunction &) { return false; }) {}
 
 void Localizer::init(MachineFunction &MF) {
   MRI = &MF.getRegInfo();
@@ -212,6 +216,10 @@ bool Localizer::runOnMachineFunction(MachineFunction &MF) {
           MachineFunctionProperties::Property::FailedISel))
     return false;
 
+  // Don't run the pass if the target asked so.
+  if (DoNotRunPass(MF))
+    return false;
+
   LLVM_DEBUG(dbgs() << "Localize instructions for: " << MF.getName() << '\n');
 
   init(MF);