[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

llvm-svn: 239325

include/llvm/CodeGen/Passes.h

@@ -21,7 +21,6 @@
 
 namespace llvm {
 
-class FunctionPass;
 class MachineFunctionPass;
 class PassConfigImpl;
 class PassInfo;
@@ -519,6 +518,8 @@ namespace llvm {
   /// IfConverter - This pass performs machine code if conversion.
   extern char &IfConverterID;
 
+  FunctionPass *createIfConverter(std::function<bool(const Function &)> Ftor);
+
   /// MachineBlockPlacement - This pass places basic blocks based on branch
   /// probabilities.
   extern char &MachineBlockPlacementID;
@@ -613,6 +614,9 @@ namespace llvm {
   /// UnpackMachineBundles - This pass unpack machine instruction bundles.
   extern char &UnpackMachineBundlesID;
 
+  FunctionPass *
+  createUnpackMachineBundles(std::function<bool(const Function &)> Ftor);
+
   /// FinalizeMachineBundles - This pass finalize machine instruction
   /// bundles (created earlier, e.g. during pre-RA scheduling).
   extern char &FinalizeMachineBundlesID;

include/llvm/Transforms/Scalar.h

@@ -16,10 +16,12 @@
 #define LLVM_TRANSFORMS_SCALAR_H
 
 #include "llvm/ADT/StringRef.h"
+#include <functional>
 
 namespace llvm {
 
 class BasicBlockPass;
+class Function;
 class FunctionPass;
 class ModulePass;
 class Pass;
@@ -245,7 +247,8 @@ FunctionPass *createJumpThreadingPass(int Threshold = -1);
 // CFGSimplification - Merge basic blocks, eliminate unreachable blocks,
 // simplify terminator instructions, etc...
 //
-FunctionPass *createCFGSimplificationPass(int Threshold = -1);
+FunctionPass *createCFGSimplificationPass(
+    int Threshold = -1, std::function<bool(const Function &)> Ftor = nullptr);
 
 //===----------------------------------------------------------------------===//
 //

lib/CodeGen/IfConversion.cpp

@@ -170,9 +170,12 @@ namespace {
     bool PreRegAlloc;
     bool MadeChange;
     int FnNum;
+    std::function<bool(const Function &)> PredicateFtor;
+
   public:
     static char ID;
-    IfConverter() : MachineFunctionPass(ID), FnNum(-1) {
+    IfConverter(std::function<bool(const Function &)> Ftor = nullptr)
+        : MachineFunctionPass(ID), FnNum(-1), PredicateFtor(Ftor) {
       initializeIfConverterPass(*PassRegistry::getPassRegistry());
     }
 
@@ -270,6 +273,9 @@ INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
 INITIALIZE_PASS_END(IfConverter, "if-converter", "If Converter", false, false)
 
 bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
+  if (PredicateFtor && !PredicateFtor(*MF.getFunction()))
+    return false;
+
   const TargetSubtargetInfo &ST = MF.getSubtarget();
   TLI = ST.getTargetLowering();
   TII = ST.getInstrInfo();
@@ -1691,3 +1697,8 @@ void IfConverter::MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI, bool AddEdges) {
   ToBBI.IsAnalyzed = false;
   FromBBI.IsAnalyzed = false;
 }
+
+FunctionPass *
+llvm::createIfConverter(std::function<bool(const Function &)> Ftor) {
+  return new IfConverter(Ftor);
+}

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 {

lib/Target/ARM/ARM.h

@@ -16,11 +16,13 @@
 #define LLVM_LIB_TARGET_ARM_ARM_H
 
 #include "llvm/Support/CodeGen.h"
+#include <functional>
 
 namespace llvm {
 
 class ARMAsmPrinter;
 class ARMBaseTargetMachine;
+class Function;
 class FunctionPass;
 class ImmutablePass;
 class MachineInstr;
@@ -38,7 +40,8 @@ FunctionPass *createARMConstantIslandPass();
 FunctionPass *createMLxExpansionPass();
 FunctionPass *createThumb2ITBlockPass();
 FunctionPass *createARMOptimizeBarriersPass();
-FunctionPass *createThumb2SizeReductionPass();
+FunctionPass *createThumb2SizeReductionPass(
+    std::function<bool(const Function &)> Ftor = nullptr);
 
 void LowerARMMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
                                   ARMAsmPrinter &AP);

lib/Target/ARM/ARMTargetMachine.cpp

@@ -304,10 +304,6 @@ public:
     return getTM<ARMBaseTargetMachine>();
   }
 
-  const ARMSubtarget &getARMSubtarget() const {
-    return *getARMTargetMachine().getSubtargetImpl();
-  }
-
   void addIRPasses() override;
   bool addPreISel() override;
   bool addInstSelector() override;
@@ -330,10 +326,11 @@ void ARMPassConfig::addIRPasses() {
   // Cmpxchg instructions are often used with a subsequent comparison to
   // determine whether it succeeded. We can exploit existing control-flow in
   // ldrex/strex loops to simplify this, but it needs tidying up.
-  const ARMSubtarget *Subtarget = &getARMSubtarget();
-  if (Subtarget->hasAnyDataBarrier() && !Subtarget->isThumb1Only())
-    if (TM->getOptLevel() != CodeGenOpt::None && EnableAtomicTidy)
-      addPass(createCFGSimplificationPass());
+  if (TM->getOptLevel() != CodeGenOpt::None && EnableAtomicTidy)
+    addPass(createCFGSimplificationPass(-1, [this](const Function &F) {
+      const auto &ST = this->TM->getSubtarget<ARMSubtarget>(F);
+      return ST.hasAnyDataBarrier() && !ST.isThumb1Only();
+    }));
 
   TargetPassConfig::addIRPasses();
 }
@@ -390,10 +387,13 @@ void ARMPassConfig::addPreSched2() {
 
   if (getOptLevel() != CodeGenOpt::None) {
     // in v8, IfConversion depends on Thumb instruction widths
-    if (getARMSubtarget().restrictIT())
-      addPass(createThumb2SizeReductionPass());
-    if (!getARMSubtarget().isThumb1Only())
-      addPass(&IfConverterID);
+    addPass(createThumb2SizeReductionPass([this](const Function &F) {
+      return this->TM->getSubtarget<ARMSubtarget>(F).restrictIT();
+    }));
+
+    addPass(createIfConverter([this](const Function &F) {
+      return !this->TM->getSubtarget<ARMSubtarget>(F).isThumb1Only();
+    }));
   }
   addPass(createThumb2ITBlockPass());
 }
@@ -402,8 +402,9 @@ void ARMPassConfig::addPreEmitPass() {
   addPass(createThumb2SizeReductionPass());
 
   // Constant island pass work on unbundled instructions.
-  if (getARMSubtarget().isThumb2())
-    addPass(&UnpackMachineBundlesID);
+  addPass(createUnpackMachineBundles([this](const Function &F) {
+    return this->TM->getSubtarget<ARMSubtarget>(F).isThumb2();
+  }));
 
   // Don't optimize barriers at -O0.
   if (getOptLevel() != CodeGenOpt::None)

lib/Target/ARM/Thumb2SizeReduction.cpp

@@ -133,7 +133,7 @@ namespace {
   class Thumb2SizeReduce : public MachineFunctionPass {
   public:
     static char ID;
-    Thumb2SizeReduce();
+    Thumb2SizeReduce(std::function<bool(const Function &)> Ftor);
 
     const Thumb2InstrInfo *TII;
     const ARMSubtarget *STI;
@@ -198,11 +198,14 @@ namespace {
     };
 
     SmallVector<MBBInfo, 8> BlockInfo;
+
+    std::function<bool(const Function &)> PredicateFtor;
   };
   char Thumb2SizeReduce::ID = 0;
 }
 
-Thumb2SizeReduce::Thumb2SizeReduce() : MachineFunctionPass(ID) {
+Thumb2SizeReduce::Thumb2SizeReduce(std::function<bool(const Function &)> Ftor)
+    : MachineFunctionPass(ID), PredicateFtor(Ftor) {
   OptimizeSize = MinimizeSize = false;
   for (unsigned i = 0, e = array_lengthof(ReduceTable); i != e; ++i) {
     unsigned FromOpc = ReduceTable[i].WideOpc;
@@ -1000,6 +1003,9 @@ bool Thumb2SizeReduce::ReduceMBB(MachineBasicBlock &MBB) {
 }
 
 bool Thumb2SizeReduce::runOnMachineFunction(MachineFunction &MF) {
+  if (PredicateFtor && !PredicateFtor(*MF.getFunction()))
+    return false;
+
   STI = &static_cast<const ARMSubtarget &>(MF.getSubtarget());
   if (STI->isThumb1Only() || STI->prefers32BitThumb())
     return false;
@@ -1025,6 +1031,7 @@ bool Thumb2SizeReduce::runOnMachineFunction(MachineFunction &MF) {
 
 /// createThumb2SizeReductionPass - Returns an instance of the Thumb2 size
 /// reduction pass.
-FunctionPass *llvm::createThumb2SizeReductionPass() {
-  return new Thumb2SizeReduce();
+FunctionPass *llvm::createThumb2SizeReductionPass(
+    std::function<bool(const Function &)> Ftor) {
+  return new Thumb2SizeReduce(Ftor);
 }

lib/Transforms/Scalar/SimplifyCFGPass.cpp

@@ -193,11 +193,18 @@ namespace {
 struct CFGSimplifyPass : public FunctionPass {
   static char ID; // Pass identification, replacement for typeid
   unsigned BonusInstThreshold;
-  CFGSimplifyPass(int T = -1) : FunctionPass(ID) {
+  std::function<bool(const Function &)> PredicateFtor;
+
+  CFGSimplifyPass(int T = -1,
+                  std::function<bool(const Function &)> Ftor = nullptr)
+      : FunctionPass(ID), PredicateFtor(Ftor) {
     BonusInstThreshold = (T == -1) ? UserBonusInstThreshold : unsigned(T);
     initializeCFGSimplifyPassPass(*PassRegistry::getPassRegistry());
   }
   bool runOnFunction(Function &F) override {
+    if (PredicateFtor && !PredicateFtor(F))
+      return false;
+
     if (skipOptnoneFunction(F))
       return false;
 
@@ -224,7 +231,9 @@ INITIALIZE_PASS_END(CFGSimplifyPass, "simplifycfg", "Simplify the CFG", false,
                     false)
 
 // Public interface to the CFGSimplification pass
-FunctionPass *llvm::createCFGSimplificationPass(int Threshold) {
-  return new CFGSimplifyPass(Threshold);
+FunctionPass *
+llvm::createCFGSimplificationPass(int Threshold,
+                                  std::function<bool(const Function &)> Ftor) {
+  return new CFGSimplifyPass(Threshold, Ftor);
 }
 

test/CodeGen/ARM/ifcvt-callback.ll

@@ -0,0 +1,22 @@
+; RUN: llc -march thumb %s -o - | FileCheck %s
+
+; This test checks that if-conversion pass is unconditionally added to the pass
+; pipeline and is conditionally executed based on the per-function targert-cpu
+; attribute.
+ 
+; CHECK: ite eq
+
+define i32 @test_ifcvt(i32 %a, i32 %b) #0 {
+  %tmp2 = icmp eq i32 %a, 0
+  br i1 %tmp2, label %cond_false, label %cond_true
+
+cond_true:
+  %tmp5 = add i32 %b, 1
+  ret i32 %tmp5
+
+cond_false:
+  %tmp7 = add i32 %b, -1
+  ret i32 %tmp7
+}
+
+attributes #0 = { "target-cpu"="cortex-a8" }