Initial commit of the 'landingpad' instruction.

This implements the 'landingpad' instruction. It's used to indicate that a basic
block is a landing pad. There are several restrictions on its use (see
LangRef.html for more detail). These restrictions allow the exception handling
code to gather the information it needs in a much more sane way.

This patch has the definition, implementation, C interface, parsing, and bitcode
support in it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137501 91177308-0d34-0410-b5e6-96231b3b80d8

7 files changed, 143 insertions, 4 deletions

diff --git a/include/llvm-c/Core.h b/include/llvm-c/Core.h
index 0acf5a23af..2562757a2e 100644
--- a/include/llvm-c/Core.h
+++ b/include/llvm-c/Core.h
@@ -191,7 +191,8 @@ typedef enum {
   LLVMAtomicRMW      = 57,
 
   /* Exception Handling Operators */
-  LLVMResume         = 58
+  LLVMResume         = 58,
+  LLVMLandingPad     = 59
 
 } LLVMOpcode;
 
@@ -283,6 +284,11 @@ typedef enum {
   LLVMRealPredicateTrue   /**< Always true (always folded) */
 } LLVMRealPredicate;
 
+typedef enum {
+  LLVMLandingPadCatch,    /**< A catch clause   */
+  LLVMLandingPadFilter    /**< A filter clause  */
+} LLVMLandingPadClauseTy;
+
 void LLVMInitializeCore(LLVMPassRegistryRef R);
 
 
@@ -469,6 +475,7 @@ LLVMTypeRef LLVMX86MMXType(void);
       macro(GetElementPtrInst)              \
       macro(InsertElementInst)              \
       macro(InsertValueInst)                \
+      macro(LandingPadInst)                 \
       macro(PHINode)                        \
       macro(SelectInst)                     \
       macro(ShuffleVectorInst)              \
@@ -837,6 +844,12 @@ void LLVMAddCase(LLVMValueRef Switch, LLVMValueRef OnVal,
 /* Add a destination to the indirectbr instruction */
 void LLVMAddDestination(LLVMValueRef IndirectBr, LLVMBasicBlockRef Dest);
 
+/* Add a catch or filter clause to the landingpad instruction */
+void LLVMAddClause(LLVMValueRef LandingPad, LLVMValueRef ClauseVal);
+
+/* Set the 'cleanup' flag in the landingpad instruction */
+void LLVMSetCleanup(LLVMValueRef LandingPad, LLVMBool Val);
+
 /* Arithmetic */
 LLVMValueRef LLVMBuildAdd(LLVMBuilderRef, LLVMValueRef LHS, LLVMValueRef RHS,
                           const char *Name);
diff --git a/include/llvm/BasicBlock.h b/include/llvm/BasicBlock.h
index 3b953c06a8..d5966290a1 100644
--- a/include/llvm/BasicBlock.h
+++ b/include/llvm/BasicBlock.h
@@ -22,6 +22,7 @@
 
 namespace llvm {
 
+class LandingPadInst;
 class TerminatorInst;
 class LLVMContext;
 class BlockAddress;
@@ -258,6 +259,14 @@ public:
   /// to refer to basic block New instead of to us.
   void replaceSuccessorsPhiUsesWith(BasicBlock *New);
 
+  /// isLandingPad - Return true if this basic block is a landing pad. I.e.,
+  /// it's the destination of the 'unwind' edge of an invoke instruction.
+  bool isLandingPad() const;
+
+  /// getLandingPadInst() - Return the landingpad instruction associated with
+  /// the landing pad.
+  LandingPadInst *getLandingPadInst();
+
 private:
   /// AdjustBlockAddressRefCount - BasicBlock stores the number of BlockAddress
   /// objects using it.  This is almost always 0, sometimes one, possibly but
diff --git a/include/llvm/Bitcode/LLVMBitCodes.h b/include/llvm/Bitcode/LLVMBitCodes.h
index e2e5f0b087..4b0dcc3623 100644
--- a/include/llvm/Bitcode/LLVMBitCodes.h
+++ b/include/llvm/Bitcode/LLVMBitCodes.h
@@ -308,9 +308,10 @@ namespace bitc {
                                      //             align, vol,
                                      //             ordering, synchscope]
     FUNC_CODE_INST_RESUME      = 39, // RESUME:     [opval]
-    FUNC_CODE_INST_LOADATOMIC  = 40, // LOAD: [opty, op, align, vol,
+    FUNC_CODE_INST_LANDINGPAD  = 40, // LANDINGPAD: [ty,val,val,num,id0,val0...]
+    FUNC_CODE_INST_LOADATOMIC  = 41, // LOAD: [opty, op, align, vol,
                                      //        ordering, synchscope]
-    FUNC_CODE_INST_STOREATOMIC = 41  // STORE: [ptrty,ptr,val, align, vol
+    FUNC_CODE_INST_STOREATOMIC = 42  // STORE: [ptrty,ptr,val, align, vol
                                      //         ordering, synchscope]
   };
 } // End bitc namespace
diff --git a/include/llvm/Instruction.def b/include/llvm/Instruction.def
index 2e02b670cf..d36e4be1d9 100644
--- a/include/llvm/Instruction.def
+++ b/include/llvm/Instruction.def
@@ -172,7 +172,8 @@ HANDLE_OTHER_INST(55, InsertElement, InsertElementInst)  // insert into vector
 HANDLE_OTHER_INST(56, ShuffleVector, ShuffleVectorInst)  // shuffle two vectors.
 HANDLE_OTHER_INST(57, ExtractValue, ExtractValueInst)// extract from aggregate
 HANDLE_OTHER_INST(58, InsertValue, InsertValueInst)  // insert into aggregate
-  LAST_OTHER_INST(58)
+HANDLE_OTHER_INST(59, LandingPad, LandingPadInst)  // Landing pad instruction.
+  LAST_OTHER_INST(59)
 
 #undef  FIRST_TERM_INST
 #undef HANDLE_TERM_INST
diff --git a/include/llvm/Instructions.h b/include/llvm/Instructions.h
index 4103362dd8..2b681abbbd 100644
--- a/include/llvm/Instructions.h
+++ b/include/llvm/Instructions.h
@@ -2106,6 +2106,111 @@ struct OperandTraits<PHINode> : public HungoffOperandTraits<2> {
 
 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(PHINode, Value)
 
+//===----------------------------------------------------------------------===//
+//                           LandingPadInst Class
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------------------------------------------
+/// LandingPadInst - The landingpad instruction holds all of the information
+/// necessary to generate correct exception handling. The landingpad instruction
+/// cannot be moved from the top of a landing pad block, which itself is
+/// accessible only from the 'unwind' edge of an invoke. This uses the
+/// SubclassData field in Value to store whether or not the landingpad is a
+/// cleanup.
+///
+class LandingPadInst : public Instruction {
+  /// ReservedSpace - The number of operands actually allocated.  NumOperands is
+  /// the number actually in use.
+  unsigned ReservedSpace;
+  LandingPadInst(const LandingPadInst &LP);
+public:
+  enum ClauseType { Catch, Filter };
+private:
+  void *operator new(size_t, unsigned);  // DO NOT IMPLEMENT
+  // Allocate space for exactly zero operands.
+  void *operator new(size_t s) {
+    return User::operator new(s, 0);
+  }
+  void growOperands(unsigned Size);
+  void init(Value *PersFn, unsigned NumReservedValues, const Twine &NameStr);
+
+  explicit LandingPadInst(Type *RetTy, Value *PersonalityFn,
+                          unsigned NumReservedValues, const Twine &NameStr,
+                          Instruction *InsertBefore);
+  explicit LandingPadInst(Type *RetTy, Value *PersonalityFn,
+                          unsigned NumReservedValues, const Twine &NameStr,
+                          BasicBlock *InsertAtEnd);
+protected:
+  virtual LandingPadInst *clone_impl() const;
+public:
+  /// Constructors - NumReservedClauses is a hint for the number of incoming
+  /// clauses that this landingpad will have (use 0 if you really have no idea).
+  static LandingPadInst *Create(Type *RetTy, Value *PersonalityFn,
+                                unsigned NumReservedClauses,
+                                const Twine &NameStr = "",
+                                Instruction *InsertBefore = 0);
+  static LandingPadInst *Create(Type *RetTy, Value *PersonalityFn,
+                                unsigned NumReservedClauses,
+                                const Twine &NameStr, BasicBlock *InsertAtEnd);
+  ~LandingPadInst();
+
+  /// Provide fast operand accessors
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+
+  /// getPersonalityFn - Get the personality function associated with this
+  /// landing pad.
+  Value *getPersonalityFn() const { return getOperand(0); }
+
+  /// isCleanup - Return 'true' if this landingpad instruction is a
+  /// cleanup. I.e., it should be run when unwinding even if its landing pad
+  /// doesn't catch the exception.
+  bool isCleanup() const { return getSubclassDataFromInstruction() & 1; }
+
+  /// setCleanup - Indicate that this landingpad instruction is a cleanup.
+  void setCleanup(bool V) {
+    setInstructionSubclassData((getSubclassDataFromInstruction() & ~1) |
+                               (V ? 1 : 0));
+  }
+
+  /// addClause - Add a catch or filter clause to the landing pad.
+  void addClause(Value *ClauseVal);
+
+  /// getClause - Get the value of the clause at index Idx. Use isCatch/isFilter
+  /// to determine what type of clause this is.
+  Value *getClause(unsigned Idx) const { return OperandList[Idx + 1]; }
+
+  /// isCatch - Return 'true' if the clause and index Idx is a catch clause.
+  bool isCatch(unsigned Idx) const {
+    return !isa<ArrayType>(OperandList[Idx + 1]->getType());
+  }
+
+  /// isFilter - Return 'true' if the clause and index Idx is a filter clause.
+  bool isFilter(unsigned Idx) const {
+    return isa<ArrayType>(OperandList[Idx + 1]->getType());
+  }
+
+  /// getNumClauses - Get the number of clauses for this landing pad.
+  unsigned getNumClauses() const { return getNumOperands() - 1; }
+
+  /// reserveClauses - Grow the size of the operand list to accomodate the new
+  /// number of clauses.
+  void reserveClauses(unsigned Size) { growOperands(Size); }
+
+  // Methods for support type inquiry through isa, cast, and dyn_cast:
+  static inline bool classof(const LandingPadInst *) { return true; }
+  static inline bool classof(const Instruction *I) {
+    return I->getOpcode() == Instruction::LandingPad;
+  }
+  static inline bool classof(const Value *V) {
+    return isa<Instruction>(V) && classof(cast<Instruction>(V));
+  }
+};
+
+template <>
+struct OperandTraits<LandingPadInst> : public HungoffOperandTraits<2> {
+};
+
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(LandingPadInst, Value)
 
 //===----------------------------------------------------------------------===//
 //                               ReturnInst Class
@@ -2695,6 +2800,10 @@ public:
     Op<-1>() = reinterpret_cast<Value*>(B);
   }
 
+  /// getLandingPadInst - Get the landingpad instruction from the landing pad
+  /// block (the unwind destination).
+  LandingPadInst *getLandingPadInst() const;
+
   BasicBlock *getSuccessor(unsigned i) const {
     assert(i < 2 && "Successor # out of range for invoke!");
     return i == 0 ? getNormalDest() : getUnwindDest();
diff --git a/include/llvm/Support/IRBuilder.h b/include/llvm/Support/IRBuilder.h
index 133b1c3fd5..782800173f 100644
--- a/include/llvm/Support/IRBuilder.h
+++ b/include/llvm/Support/IRBuilder.h
@@ -1204,6 +1204,11 @@ public:
     return Insert(InsertValueInst::Create(Agg, Val, Idxs), Name);
   }
 
+  LandingPadInst *CreateLandingPad(Type *Ty, Value *PersFn, unsigned NumClauses,
+                                   const Twine &Name = "") {
+    return Insert(LandingPadInst::Create(Ty, PersFn, NumClauses, Name));
+  }
+
   //===--------------------------------------------------------------------===//
   // Utility creation methods
   //===--------------------------------------------------------------------===//
diff --git a/include/llvm/Support/InstVisitor.h b/include/llvm/Support/InstVisitor.h
index 591de6f40d..a661c4fac6 100644
--- a/include/llvm/Support/InstVisitor.h
+++ b/include/llvm/Support/InstVisitor.h
@@ -195,6 +195,7 @@ public:
   RetTy visitShuffleVectorInst(ShuffleVectorInst &I) { DELEGATE(Instruction); }
   RetTy visitExtractValueInst(ExtractValueInst &I)  { DELEGATE(Instruction);}
   RetTy visitInsertValueInst(InsertValueInst &I)    { DELEGATE(Instruction); }
+  RetTy visitLandingPadInst(LandingPadInst &I)      { DELEGATE(Instruction); }
 
   // Next level propagators: If the user does not overload a specific
   // instruction type, they can overload one of these to get the whole class