Re-land r235154-r235156 under the existing -sehprepare flag

Keep the old SEH fan-in lowering on by default for now, since projects
rely on it.  This will make it easy to test this change with a simple
flag flip.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235399 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/FunctionLoweringInfo.h

@@ -221,6 +221,8 @@ public:
   int getArgumentFrameIndex(const Argument *A);
 
 private:
+  void addSEHHandlersForLPads();
+
   /// LiveOutRegInfo - Information about live out vregs.
   IndexedMap<LiveOutInfo, VirtReg2IndexFunctor> LiveOutRegInfo;
 };

include/llvm/CodeGen/MachineModuleInfo.h

@@ -51,6 +51,7 @@ namespace llvm {
 // Forward declarations.
 class Constant;
 class GlobalVariable;
+class BlockAddress;
 class MDNode;
 class MMIAddrLabelMap;
 class MachineBasicBlock;
@@ -60,6 +61,14 @@ class PointerType;
 class StructType;
 struct WinEHFuncInfo;
 
+struct SEHHandler {
+  // Filter or finally function. Null indicates a catch-all.
+  const Function *FilterOrFinally;
+
+  // Address of block to recover at. Null for a finally handler.
+  const BlockAddress *RecoverBA;
+};
+
 //===----------------------------------------------------------------------===//
 /// LandingPadInfo - This structure is used to retain landing pad info for
 /// the current function.
@@ -69,6 +78,7 @@ struct LandingPadInfo {
   SmallVector<MCSymbol *, 1> BeginLabels;  // Labels prior to invoke.
   SmallVector<MCSymbol *, 1> EndLabels;    // Labels after invoke.
   SmallVector<MCSymbol *, 1> ClauseLabels; // Labels for each clause.
+  SmallVector<SEHHandler, 1> SEHHandlers;  // SEH handlers active at this lpad.
   MCSymbol *LandingPadLabel;               // Label at beginning of landing pad.
   const Function *Personality;             // Personality function.
   std::vector<int> TypeIds;               // List of type ids (filters negative).
@@ -356,6 +366,12 @@ public:
   /// each clause gets its own basic block.
   MCSymbol *addClauseForLandingPad(MachineBasicBlock *LandingPad);
 
+  void addSEHCatchHandler(MachineBasicBlock *LandingPad, const Function *Filter,
+                          const BlockAddress *RecoverLabel);
+
+  void addSEHCleanupHandler(MachineBasicBlock *LandingPad,
+                            const Function *Cleanup);
+
   /// getTypeIDFor - Return the type id for the specified typeinfo.  This is
   /// function wide.
   unsigned getTypeIDFor(const GlobalValue *TI);

include/llvm/CodeGen/SelectionDAGISel.h

@@ -260,7 +260,10 @@ private:
   SDNode *MorphNode(SDNode *Node, unsigned TargetOpc, SDVTList VTs,
                     ArrayRef<SDValue> Ops, unsigned EmitNodeInfo);
 
-  void PrepareEHLandingPad();
+  /// Prepares the landing pad to take incoming values or do other EH
+  /// personality specific tasks. Returns true if the block should be
+  /// instruction selected, false if no code should be emitted for it.
+  bool PrepareEHLandingPad();
 
   /// \brief Perform instruction selection on all basic blocks in the function.
   void SelectAllBasicBlocks(const Function &Fn);