[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/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);
 }