Move the personality function from LandingPadInst to Function

The personality routine currently lives in the LandingPadInst.

This isn't desirable because:
- All LandingPadInsts in the same function must have the same
  personality routine.  This means that each LandingPadInst beyond the
  first has an operand which produces no additional information.

- There is ongoing work to introduce EH IR constructs other than
  LandingPadInst.  Moving the personality routine off of any one
  particular Instruction and onto the parent function seems a lot better
  than have N different places a personality function can sneak onto an
  exceptional function.

Differential Revision: http://reviews.llvm.org/D10429

llvm-svn: 239940

llvm/docs/BitCodeFormat.rst

@@ -741,7 +741,7 @@ global variable. The operand fields are:
 MODULE_CODE_FUNCTION Record
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-``[FUNCTION, type, callingconv, isproto, linkage, paramattr, alignment, section, visibility, gc, prologuedata, dllstorageclass, comdat, prefixdata]``
+``[FUNCTION, type, callingconv, isproto, linkage, paramattr, alignment, section, visibility, gc, prologuedata, dllstorageclass, comdat, prefixdata, personalityfn]``
 
 The ``FUNCTION`` record (code 8) marks the declaration or definition of a
 function. The operand fields are:
@@ -795,6 +795,8 @@ function. The operand fields are:
 * *prefixdata*: If non-zero, the value index of the prefix data for this function,
   plus 1.
 
+* *personalityfn*: If non-zero, the value index of the personality function for this function,
+  plus 1.
 
 MODULE_CODE_ALIAS Record
 ^^^^^^^^^^^^^^^^^^^^^^^^

llvm/docs/LangRef.rst

@@ -635,8 +635,9 @@ attributes <paramattrs>`), optional :ref:`function attributes <fnattrs>`,
 an optional section, an optional alignment,
 an optional :ref:`comdat <langref_comdats>`,
 an optional :ref:`garbage collector name <gc>`, an optional :ref:`prefix <prefixdata>`,
-an optional :ref:`prologue <prologuedata>`, an opening
-curly brace, a list of basic blocks, and a closing curly brace.
+an optional :ref:`prologue <prologuedata>`,
+an optional :ref:`personality <personalityfn>`,
+an opening curly brace, a list of basic blocks, and a closing curly brace.
 
 LLVM function declarations consist of the "``declare``" keyword, an
 optional :ref:`linkage type <linkage>`, an optional :ref:`visibility
@@ -683,7 +684,8 @@ Syntax::
            [cconv] [ret attrs]
            <ResultType> @<FunctionName> ([argument list])
            [unnamed_addr] [fn Attrs] [section "name"] [comdat [($name)]]
-           [align N] [gc] [prefix Constant] [prologue Constant] { ... }
+           [align N] [gc] [prefix Constant] [prologue Constant]
+           [personality Constant] { ... }
 
 The argument list is a comma seperated sequence of arguments where each
 argument is of the following form
@@ -1130,6 +1132,14 @@ A function may have prologue data but no body.  This has similar semantics
 to the ``available_externally`` linkage in that the data may be used by the
 optimizers but will not be emitted in the object file.
 
+.. _personalityfn:
+
+Personality Function
+-------------
+
+The ``personality`` attribute permits functions to specify what function
+to use for exception handling.
+
 .. _attrgrp:
 
 Attribute Groups
@@ -7283,8 +7293,8 @@ Syntax:
 
 ::
 
-      <resultval> = landingpad <resultty> personality <type> <pers_fn> <clause>+
-      <resultval> = landingpad <resultty> personality <type> <pers_fn> cleanup <clause>*
+      <resultval> = landingpad <resultty> <clause>+
+      <resultval> = landingpad <resultty> cleanup <clause>*
 
       <clause> := catch <type> <value>
       <clause> := filter <array constant type> <array constant>
@@ -7296,14 +7306,13 @@ The '``landingpad``' instruction is used by `LLVM's exception handling
 system <ExceptionHandling.html#overview>`_ to specify that a basic block
 is a landing pad --- one where the exception lands, and corresponds to the
 code found in the ``catch`` portion of a ``try``/``catch`` sequence. It
-defines values supplied by the personality function (``pers_fn``) upon
+defines values supplied by the :ref:`personality function <personalityfn>` upon
 re-entry to the function. The ``resultval`` has the type ``resultty``.
 
 Arguments:
 """"""""""
 
-This instruction takes a ``pers_fn`` value. This is the personality
-function associated with the unwinding mechanism. The optional
+The optional
 ``cleanup`` flag indicates that the landing pad block is a cleanup.
 
 A ``clause`` begins with the clause type --- ``catch`` or ``filter`` --- and
@@ -7318,7 +7327,7 @@ Semantics:
 """"""""""
 
 The '``landingpad``' instruction defines the values which are set by the
-personality function (``pers_fn``) upon re-entry to the function, and
+:ref:`personality function <personalityfn>` upon re-entry to the function, and
 therefore the "result type" of the ``landingpad`` instruction. As with
 calling conventions, how the personality function results are
 represented in LLVM IR is target specific.
@@ -7341,22 +7350,20 @@ The ``landingpad`` instruction has several restrictions:
    pad block.
 -  A basic block that is not a landing pad block may not include a
    '``landingpad``' instruction.
--  All '``landingpad``' instructions in a function must have the same
-   personality function.
 
 Example:
 """"""""
 
 .. code-block:: llvm
 
       ;; A landing pad which can catch an integer.
-      %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
+      %res = landingpad { i8*, i32 }
                catch i8** @_ZTIi
       ;; A landing pad that is a cleanup.
-      %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
+      %res = landingpad { i8*, i32 }
                cleanup
       ;; A landing pad which can catch an integer and can only throw a double.
-      %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
+      %res = landingpad { i8*, i32 }
                catch i8** @_ZTIi
                filter [1 x i8**] [@_ZTId]
 

llvm/include/llvm/Analysis/LibCallSemantics.h

@@ -206,7 +206,7 @@ class InvokeInst;
     llvm_unreachable("invalid enum");
   }
 
-  bool canSimplifyInvokeNoUnwind(const InvokeInst *II);
+  bool canSimplifyInvokeNoUnwind(const Function *F);
 
 } // end namespace llvm
 

llvm/include/llvm/Bitcode/LLVMBitCodes.h

@@ -342,7 +342,7 @@ namespace bitc {
                                      //             align, vol,
                                      //             ordering, synchscope]
     FUNC_CODE_INST_RESUME      = 39, // RESUME:     [opval]
-    FUNC_CODE_INST_LANDINGPAD  = 40, // LANDINGPAD: [ty,val,val,num,id0,val0...]
+    FUNC_CODE_INST_LANDINGPAD_OLD  = 40, // LANDINGPAD: [ty,val,val,num,id0,val0...]
     FUNC_CODE_INST_LOADATOMIC  = 41, // LOAD: [opty, op, align, vol,
                                      //        ordering, synchscope]
     FUNC_CODE_INST_STOREATOMIC_OLD = 42, // STORE: [ptrty,ptr,val, align, vol
@@ -352,6 +352,7 @@ namespace bitc {
     FUNC_CODE_INST_STOREATOMIC = 45, // STORE: [ptrty,ptr,val, align, vol
     FUNC_CODE_INST_CMPXCHG     = 46, // CMPXCHG: [ptrty,ptr,valty,cmp,new, align,
                                      //           vol,ordering,synchscope]
+    FUNC_CODE_INST_LANDINGPAD  = 47, // LANDINGPAD: [ty,val,num,id0,val0...]
   };
 
   enum UseListCodes {

llvm/include/llvm/IR/Function.h

@@ -25,6 +25,7 @@
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CallingConv.h"
 #include "llvm/IR/GlobalObject.h"
+#include "llvm/IR/OperandTraits.h"
 #include "llvm/Support/Compiler.h"
 
 namespace llvm {
@@ -119,11 +120,22 @@ class Function : public GlobalObject, public ilist_node<Function> {
 public:
   static Function *Create(FunctionType *Ty, LinkageTypes Linkage,
                           const Twine &N = "", Module *M = nullptr) {
-    return new(0) Function(Ty, Linkage, N, M);
+    return new(1) Function(Ty, Linkage, N, M);
   }
 
   ~Function() override;
 
+  /// \brief Provide fast operand accessors
+  DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
+
+  /// \brief Get the personality function associated with this function.
+  bool hasPersonalityFn() const { return getNumOperands() != 0; }
+  Constant *getPersonalityFn() const {
+    assert(hasPersonalityFn());
+    return cast<Constant>(Op<0>());
+  }
+  void setPersonalityFn(Constant *C);
+
   Type *getReturnType() const;           // Return the type of the ret val
   FunctionType *getFunctionType() const; // Return the FunctionType for me
 
@@ -601,6 +613,11 @@ ilist_traits<Argument>::getSymTab(Function *F) {
   return F ? &F->getValueSymbolTable() : nullptr;
 }
 
+template <>
+struct OperandTraits<Function> : public OptionalOperandTraits<Function> {};
+
+DEFINE_TRANSPARENT_OPERAND_ACCESSORS(Function, Value)
+
 } // End llvm namespace
 
 #endif

llvm/include/llvm/IR/IRBuilder.h

@@ -1556,9 +1556,9 @@ class IRBuilder : public IRBuilderBase, public Inserter {
     return Insert(InsertValueInst::Create(Agg, Val, Idxs), Name);
   }
 
-  LandingPadInst *CreateLandingPad(Type *Ty, Value *PersFn, unsigned NumClauses,
+  LandingPadInst *CreateLandingPad(Type *Ty, unsigned NumClauses,
                                    const Twine &Name = "") {
-    return Insert(LandingPadInst::Create(Ty, PersFn, NumClauses), Name);
+    return Insert(LandingPadInst::Create(Ty, NumClauses), Name);
   }
 
   //===--------------------------------------------------------------------===//

llvm/include/llvm/IR/Instructions.h

@@ -2437,34 +2437,27 @@ class LandingPadInst : public Instruction {
     return User::operator new(s);
   }
   void growOperands(unsigned Size);
-  void init(Value *PersFn, unsigned NumReservedValues, const Twine &NameStr);
+  void init(unsigned NumReservedValues, const Twine &NameStr);
+
+  explicit LandingPadInst(Type *RetTy, unsigned NumReservedValues,
+                          const Twine &NameStr, Instruction *InsertBefore);
+  explicit LandingPadInst(Type *RetTy, unsigned NumReservedValues,
+                          const Twine &NameStr, BasicBlock *InsertAtEnd);
 
-  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:
   LandingPadInst *clone_impl() const override;
 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,
+  static LandingPadInst *Create(Type *RetTy, unsigned NumReservedClauses,
                                 const Twine &NameStr = "",
                                 Instruction *InsertBefore = nullptr);
-  static LandingPadInst *Create(Type *RetTy, Value *PersonalityFn,
-                                unsigned NumReservedClauses,
+  static LandingPadInst *Create(Type *RetTy, unsigned NumReservedClauses,
                                 const Twine &NameStr, BasicBlock *InsertAtEnd);
 
   /// 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.
@@ -2482,21 +2475,21 @@ class LandingPadInst : public Instruction {
   /// Get the value of the clause at index Idx. Use isCatch/isFilter to
   /// determine what type of clause this is.
   Constant *getClause(unsigned Idx) const {
-    return cast<Constant>(getOperandList()[Idx + 1]);
+    return cast<Constant>(getOperandList()[Idx]);
   }
 
   /// isCatch - Return 'true' if the clause and index Idx is a catch clause.
   bool isCatch(unsigned Idx) const {
-    return !isa<ArrayType>(getOperandList()[Idx + 1]->getType());
+    return !isa<ArrayType>(getOperandList()[Idx]->getType());
   }
 
   /// isFilter - Return 'true' if the clause and index Idx is a filter clause.
   bool isFilter(unsigned Idx) const {
-    return isa<ArrayType>(getOperandList()[Idx + 1]->getType());
+    return isa<ArrayType>(getOperandList()[Idx]->getType());
   }
 
   /// getNumClauses - Get the number of clauses for this landing pad.
-  unsigned getNumClauses() const { return getNumOperands() - 1; }
+  unsigned getNumClauses() const { return getNumOperands(); }
 
   /// reserveClauses - Grow the size of the operand list to accommodate the new
   /// number of clauses.
@@ -2512,7 +2505,7 @@ class LandingPadInst : public Instruction {
 };
 
 template <>
-struct OperandTraits<LandingPadInst> : public HungoffOperandTraits<2> {
+struct OperandTraits<LandingPadInst> : public HungoffOperandTraits<1> {
 };
 
 DEFINE_TRANSPARENT_OPERAND_ACCESSORS(LandingPadInst, Value)

llvm/include/llvm/IR/User.h

@@ -150,6 +150,19 @@ class User : public Value {
     NumUserOperands = NumOps;
   }
 
+  /// Set the number of operands on a Function.
+  ///
+  /// Function always allocates space for a single operands, but
+  /// doesn't always use it.
+  ///
+  /// FIXME: As that the number of operands is used to find the start of
+  /// the allocated memory in operator delete, we need to always think we have
+  /// 1 operand before delete.
+  void setFunctionNumOperands(unsigned NumOps) {
+    assert(NumOps <= 1 && "Function can only have 0 or 1 operands");
+    NumUserOperands = NumOps;
+  }
+
   /// \brief Subclasses with hung off uses need to manage the operand count
   /// themselves.  In these instances, the operand count isn't used to find the
   /// OperandList, so there's no issue in having the operand count change.

llvm/lib/Analysis/LibCallSemantics.cpp

@@ -80,9 +80,8 @@ EHPersonality llvm::classifyEHPersonality(const Value *Pers) {
     .Default(EHPersonality::Unknown);
 }
 
-bool llvm::canSimplifyInvokeNoUnwind(const InvokeInst *II) {
-  const LandingPadInst *LP = II->getLandingPadInst();
-  EHPersonality Personality = classifyEHPersonality(LP->getPersonalityFn());
+bool llvm::canSimplifyInvokeNoUnwind(const Function *F) {
+  EHPersonality Personality = classifyEHPersonality(F->getPersonalityFn());
   // We can't simplify any invokes to nounwind functions if the personality
   // function wants to catch asynch exceptions.  The nounwind attribute only
   // implies that the function does not throw synchronous exceptions.

llvm/lib/AsmParser/LLParser.cpp

@@ -4057,7 +4057,7 @@ bool LLParser::ParseTypeAndBasicBlock(BasicBlock *&BB, LocTy &Loc,
 /// FunctionHeader
 ///   ::= OptionalLinkage OptionalVisibility OptionalCallingConv OptRetAttrs
 ///       OptUnnamedAddr Type GlobalName '(' ArgList ')' OptFuncAttrs OptSection
-///       OptionalAlign OptGC OptionalPrefix OptionalPrologue
+///       OptionalAlign OptGC OptionalPrefix OptionalPrologue OptPersonalityFn
 bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
   // Parse the linkage.
   LocTy LinkageLoc = Lex.getLoc();
@@ -4139,6 +4139,7 @@ bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
   LocTy UnnamedAddrLoc;
   Constant *Prefix = nullptr;
   Constant *Prologue = nullptr;
+  Constant *PersonalityFn = nullptr;
   Comdat *C;
 
   if (ParseArgumentList(ArgList, isVarArg) ||
@@ -4155,7 +4156,9 @@ bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
       (EatIfPresent(lltok::kw_prefix) &&
        ParseGlobalTypeAndValue(Prefix)) ||
       (EatIfPresent(lltok::kw_prologue) &&
-       ParseGlobalTypeAndValue(Prologue)))
+       ParseGlobalTypeAndValue(Prologue)) ||
+      (EatIfPresent(lltok::kw_personality) &&
+       ParseGlobalTypeAndValue(PersonalityFn)))
     return true;
 
   if (FuncAttrs.contains(Attribute::Builtin))
@@ -4254,6 +4257,7 @@ bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
   Fn->setAlignment(Alignment);
   Fn->setSection(Section);
   Fn->setComdat(C);
+  Fn->setPersonalityFn(PersonalityFn);
   if (!GC.empty()) Fn->setGC(GC.c_str());
   Fn->setPrefixData(Prefix);
   Fn->setPrologueData(Prologue);
@@ -5105,14 +5109,11 @@ int LLParser::ParsePHI(Instruction *&Inst, PerFunctionState &PFS) {
 ///   ::= 'filter' TypeAndValue ( ',' TypeAndValue )*
 bool LLParser::ParseLandingPad(Instruction *&Inst, PerFunctionState &PFS) {
   Type *Ty = nullptr; LocTy TyLoc;
-  Value *PersFn; LocTy PersFnLoc;
 
-  if (ParseType(Ty, TyLoc) ||
-      ParseToken(lltok::kw_personality, "expected 'personality'") ||
-      ParseTypeAndValue(PersFn, PersFnLoc, PFS))
+  if (ParseType(Ty, TyLoc))
     return true;
 
-  std::unique_ptr<LandingPadInst> LP(LandingPadInst::Create(Ty, PersFn, 0));
+  std::unique_ptr<LandingPadInst> LP(LandingPadInst::Create(Ty, 0));
   LP->setCleanup(EatIfPresent(lltok::kw_cleanup));
 
   while (Lex.getKind() == lltok::kw_catch || Lex.getKind() == lltok::kw_filter){