[MachineInstr] make getCalledFunction method of MachineInstr

[nickdesaulniers]

Summary

This will be useful in other places in a follow up commit.

[arsenm]

It's a sketchy function to begin with, making a lot of assumptions about what a call looks like.

llvm/include/llvm/CodeGen/MachineInstr.h

876

This doesn't check it's a call

llvm/lib/CodeGen/MachineInstr.cpp

2383

Preserve the braces

2385

This also misses aliases, maybe it should just return the GlobalValue?

llvm/include/llvm/CodeGen/MachineInstr.h

 
 class DILabel;
 class Instruction;
 class MDNode;
 class AAResults;
 template <typename T> class ArrayRef;
 class DIExpression;
 class DILocalVariable;
+class Function;
 class MachineBasicBlock;
 class MachineFunction;
 class MachineRegisterInfo;
 class ModuleSlotTracker;
 class raw_ostream;
 template <typename T> class SmallVectorImpl;
 class SmallBitVector;
 class StringRef;
public:
   /// i.e., a catchpad or a cleanuppad instruction.
   bool isEHScopeReturn(QueryType Type = AnyInBundle) const {
     return hasProperty(MCID::EHScopeReturn, Type);
   }
 
   bool isCall(QueryType Type = AnyInBundle) const {
     return hasProperty(MCID::Call, Type);
   }
+  /// Return a pointer to the Function being called, or nullptr if MI is not
+  /// a call instruction or is an indirect call.
+  const Function *getCalledFunction() const;
 
   /// Return true if this is a call instruction that may have an associated
   /// call site entry in the debug info.
   bool isCandidateForCallSiteEntry(QueryType Type = IgnoreBundle) const;
   /// Return true if copying, moving, or erasing this instruction requires
   /// updating Call Site Info (see \ref copyCallSiteInfo, \ref moveCallSiteInfo,
   /// \ref eraseCallSiteInfo).
   bool shouldUpdateCallSiteInfo() const;

llvm/lib/CodeGen/MachineInstr.cpp

unsigned MachineInstr::getDebugInstrNum() {
   return DebugInstrNum;
 }
 
 unsigned MachineInstr::getDebugInstrNum(MachineFunction &MF) {
   if (DebugInstrNum == 0)
     DebugInstrNum = MF.getNewDebugInstrNum();
   return DebugInstrNum;
 }
+
+const Function *MachineInstr::getCalledFunction() const {
+  for (const MachineOperand &MO : operands())
+    if (MO.isGlobal())
+      if (const auto *F = dyn_cast<Function>(MO.getGlobal()))
+        return F;
+  return nullptr;
+}

llvm/lib/CodeGen/MachineRegisterInfo.cpp

void MachineRegisterInfo::markUsesInDebugValueAsUndef(Register Reg) const {
   // Mark any DBG_VALUE* that uses Reg as undef (but don't delete it.)
   // We use make_early_inc_range because setReg invalidates the iterator.
   for (MachineInstr &UseMI : llvm::make_early_inc_range(use_instructions(Reg))) {
     if (UseMI.isDebugValue() && UseMI.hasDebugOperandForReg(Reg))
       UseMI.setDebugValueUndef();
   }
 }
 
-static const Function *getCalledFunction(const MachineInstr &MI) {
-  for (const MachineOperand &MO : MI.operands()) {
-    if (!MO.isGlobal())
-      continue;
-    const Function *Func = dyn_cast<Function>(MO.getGlobal());
-    if (Func != nullptr)
-      return Func;
-  }
-  return nullptr;
-}
-
 static bool isNoReturnDef(const MachineOperand &MO) {
   // Anything which is not a noreturn function is a real def.
   const MachineInstr &MI = *MO.getParent();
   if (!MI.isCall())
     return false;
   const MachineBasicBlock &MBB = *MI.getParent();
   if (!MBB.succ_empty())
     return false;
   const MachineFunction &MF = *MBB.getParent();
   // We need to keep correct unwind information even if the function will
   // not return, since the runtime may need it.
   if (MF.getFunction().hasFnAttribute(Attribute::UWTable))
     return false;
-  const Function *Called = getCalledFunction(MI);
+  const Function *Called = MI.getCalledFunction();
   return !(Called == nullptr || !Called->hasFnAttribute(Attribute::NoReturn) ||
            !Called->hasFnAttribute(Attribute::NoUnwind));
 }
 
 bool MachineRegisterInfo::isPhysRegModified(MCRegister PhysReg,
                                             bool SkipNoReturnDef) const {
   if (UsedPhysRegMask.test(PhysReg))
     return true;