Unify landing pad information adding routines (NFC)

[aheejin]

Summary

We have llvm::addLandingPadInfo and MachineFunction::addLandingPad,
both of which add landing pad information to populate LandingPadInfo
but are called from different locations, which was confusing. This patch
unifies them with one MachineFunction::addLandingPad function, which
now has functionlities of both functions.

[aheejin]

lib/CodeGen/MachineFunction.cpp

661

A followup patch for wasm exception handling will fill in this part. I have this else if statement just to make sure code structure is there.

[rnk]

Looks good to me.

lib/CodeGen/MachineFunction.cpp

632–633

We can simplify this to dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()), now that personalities live on the parent function, not the landingpad.

639–641

This comment is scary, but pre-existing, so I guess let's not worry about it.

[aheejin]

• Address comments

[rnk]

lgtm, thanks!

[aheejin]

Thank you!

include/llvm/CodeGen/MachineFunction.h

const std::vector<LandingPadInfo> &getLandingPads() const {
     return LandingPads;
   }
 
   /// Provide the begin and end labels of an invoke style call and associate it
   /// with a try landing pad block.
   void addInvoke(MachineBasicBlock *LandingPad,
                  MCSymbol *BeginLabel, MCSymbol *EndLabel);
 
-  /// Add a new panding pad.  Returns the label ID for the landing pad entry.
+  /// Add a new panding pad, and extract the exception handling information from
+  /// the landingpad instruction. Returns the label ID for the landing pad
+  /// entry.
   MCSymbol *addLandingPad(MachineBasicBlock *LandingPad);
 
   /// Provide the catch typeinfo for a landing pad.
   void addCatchTypeInfo(MachineBasicBlock *LandingPad,
                         ArrayRef<const GlobalValue *> TyInfo);
 
   /// Provide the filter typeinfo for a landing pad.
   void addFilterTypeInfo(MachineBasicBlock *LandingPad,
public:
   }
 
   VariableDbgInfoMapTy &getVariableDbgInfo() { return VariableDbgInfos; }
   const VariableDbgInfoMapTy &getVariableDbgInfo() const {
     return VariableDbgInfos;
   }
 };
 
-/// \name Exception Handling
-/// \{
-
-/// Extract the exception handling information from the landingpad instruction
-/// and add them to the specified machine module info.
-void addLandingPadInfo(const LandingPadInst &I, MachineBasicBlock &MBB);
-
-/// \}
-
 //===--------------------------------------------------------------------===//
 // GraphTraits specializations for function basic block graphs (CFGs)
 //===--------------------------------------------------------------------===//
 
 // Provide specializations of GraphTraits to be able to treat a
 // machine function as a graph of machine basic blocks... these are
 // the same as the machine basic block iterators, except that the root
 // node is implicitly the first node of the function.

lib/CodeGen/GlobalISel/IRTranslator.cpp

bool IRTranslator::translateInvoke(const User &U,
   return true;
 }
 
 bool IRTranslator::translateLandingPad(const User &U,
                                        MachineIRBuilder &MIRBuilder) {
   const LandingPadInst &LP = cast<LandingPadInst>(U);
 
   MachineBasicBlock &MBB = MIRBuilder.getMBB();
-  addLandingPadInfo(LP, MBB);
 
   MBB.setIsEHPad();
 
   // If there aren't registers to copy the values into (e.g., during SjLj
   // exceptions), then don't bother.
   auto &TLI = *MF->getSubtarget().getTargetLowering();
   const Constant *PersonalityFn = MF->getFunction().getPersonalityFn();
   if (TLI.getExceptionPointerRegister(PersonalityFn) == 0 &&

lib/CodeGen/MachineFunction.cpp

void MachineFunction::addInvoke(MachineBasicBlock *LandingPad,
   LP.BeginLabels.push_back(BeginLabel);
   LP.EndLabels.push_back(EndLabel);
 }
 
 MCSymbol *MachineFunction::addLandingPad(MachineBasicBlock *LandingPad) {
   MCSymbol *LandingPadLabel = Ctx.createTempSymbol();
   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
   LP.LandingPadLabel = LandingPadLabel;
+
+  const Instruction *FirstI = LandingPad->getBasicBlock()->getFirstNonPHI();
+  if (const auto *LPI = dyn_cast<LandingPadInst>(FirstI)) {
+    if (const auto *PF =
+            dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts()))
+      getMMI().addPersonality(PF);
+
+    if (LPI->isCleanup())
+      addCleanup(LandingPad);
+
+    // FIXME: New EH - Add the clauses in reverse order. This isn't 100%
+    // correct,
+    //        but we need to do it this way because of how the DWARF EH emitter
+    //        processes the clauses.
+    for (unsigned I = LPI->getNumClauses(); I != 0; --I) {
+      Value *Val = LPI->getClause(I - 1);
+      if (LPI->isCatch(I - 1)) {
+        addCatchTypeInfo(LandingPad,
+                         dyn_cast<GlobalValue>(Val->stripPointerCasts()));
+      } else {
+        // Add filters in a list.
+        auto *CVal = cast<Constant>(Val);
+        SmallVector<const GlobalValue *, 4> FilterList;
+        for (User::op_iterator II = CVal->op_begin(), IE = CVal->op_end();
+             II != IE; ++II)
+          FilterList.push_back(cast<GlobalValue>((*II)->stripPointerCasts()));
+
+        addFilterTypeInfo(LandingPad, FilterList);
+      }
+    }
+
+  } else if (const auto *CPI = dyn_cast<CatchPadInst>(FirstI)) {
+    // TODO
+
+  } else {
+    assert(isa<CleanupPadInst>(FirstI) && "Invalid landingpad!");
+  }
+
   return LandingPadLabel;
 }
 
 void MachineFunction::addCatchTypeInfo(MachineBasicBlock *LandingPad,
                                        ArrayRef<const GlobalValue *> TyInfo) {
   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
   for (unsigned N = TyInfo.size(); N; --N)
     LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
try_next:;
   int FilterID = -(1 + FilterIds.size());
   FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
   FilterIds.insert(FilterIds.end(), TyIds.begin(), TyIds.end());
   FilterEnds.push_back(FilterIds.size());
   FilterIds.push_back(0); // terminator
   return FilterID;
 }
 
-void llvm::addLandingPadInfo(const LandingPadInst &I, MachineBasicBlock &MBB) {
-  MachineFunction &MF = *MBB.getParent();
-  if (const auto *PF = dyn_cast<Function>(
-          I.getParent()->getParent()->getPersonalityFn()->stripPointerCasts()))
-    MF.getMMI().addPersonality(PF);
-
-  if (I.isCleanup())
-    MF.addCleanup(&MBB);
-
-  // FIXME: New EH - Add the clauses in reverse order. This isn't 100% correct,
-  //        but we need to do it this way because of how the DWARF EH emitter
-  //        processes the clauses.
-  for (unsigned i = I.getNumClauses(); i != 0; --i) {
-    Value *Val = I.getClause(i - 1);
-    if (I.isCatch(i - 1)) {
-      MF.addCatchTypeInfo(&MBB,
-                          dyn_cast<GlobalValue>(Val->stripPointerCasts()));
-    } else {
-      // Add filters in a list.
-      Constant *CVal = cast<Constant>(Val);
-      SmallVector<const GlobalValue *, 4> FilterList;
-      for (User::op_iterator II = CVal->op_begin(), IE = CVal->op_end();
-           II != IE; ++II)
-        FilterList.push_back(cast<GlobalValue>((*II)->stripPointerCasts()));
-
-      MF.addFilterTypeInfo(&MBB, FilterList);
-    }
-  }
-}
-
 /// \}
 
 //===----------------------------------------------------------------------===//
 //  MachineJumpTableInfo implementation
 //===----------------------------------------------------------------------===//
 
 /// Return the size of each entry in the jump table.
 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const {

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

 void SelectionDAGBuilder::visitResume(const ResumeInst &RI) {
   llvm_unreachable("SelectionDAGBuilder shouldn't visit resume instructions!");
 }
 
 void SelectionDAGBuilder::visitLandingPad(const LandingPadInst &LP) {
   assert(FuncInfo.MBB->isEHPad() &&
          "Call to landingpad not in landing pad!");
 
-  MachineBasicBlock *MBB = FuncInfo.MBB;
-  addLandingPadInfo(LP, *MBB);
-
   // If there aren't registers to copy the values into (e.g., during SjLj
   // exceptions), then don't bother to create these DAG nodes.
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   const Constant *PersonalityFn = FuncInfo.Fn->getPersonalityFn();
   if (TLI.getExceptionPointerRegister(PersonalityFn) == 0 &&
       TLI.getExceptionSelectorRegister(PersonalityFn) == 0)
     return;