[Attributor][NFC] Simplify the IRPosition interface

We pretended IRPosition came either as mutable or immutable objects
while they are basically always immutable, with a single (existing)
unfortunate exceptions. This patch cleans up the uses to deal with the
immutable version.

diff --git a/llvm/include/llvm/Transforms/IPO/Attributor.h b/llvm/include/llvm/Transforms/IPO/Attributor.h
index cb7a4b0..90d88ce 100644 (file)
--- a/llvm/include/llvm/Transforms/IPO/Attributor.h
+++ b/llvm/include/llvm/Transforms/IPO/Attributor.h
@@ -252,22 +252,14 @@ struct IRPosition {
   /// sufficient to determine where arguments will be manifested. This is, so
   /// far, only the case for call site arguments as the value is not sufficient
   /// to pinpoint them. Instead, we can use the call site as an anchor.
-  ///
-  ///{
-  Value &getAnchorValue() {
+  Value &getAnchorValue() const {
     assert(KindOrArgNo != IRP_INVALID &&
            "Invalid position does not have an anchor value!");
     return *AnchorVal;
   }
-  const Value &getAnchorValue() const {
-    return const_cast<IRPosition *>(this)->getAnchorValue();
-  }
-  ///}
 
   /// Return the associated function, if any.
-  ///
-  ///{
-  Function *getAssociatedFunction() {
+  Function *getAssociatedFunction() const {
     if (auto *CB = dyn_cast<CallBase>(AnchorVal))
       return CB->getCalledFunction();
     assert(KindOrArgNo != IRP_INVALID &&
@@ -281,15 +273,9 @@ struct IRPosition {
       return cast<Instruction>(V).getFunction();
     return nullptr;
   }
-  const Function *getAssociatedFunction() const {
-    return const_cast<IRPosition *>(this)->getAssociatedFunction();
-  }
-  ///}
 
   /// Return the associated argument, if any.
-  ///
-  ///{
-  Argument *getAssociatedArgument() {
+  Argument *getAssociatedArgument() const {
     if (auto *Arg = dyn_cast<Argument>(&getAnchorValue()))
       return Arg;
     int ArgNo = getArgNo();
@@ -300,10 +286,6 @@ struct IRPosition {
       return nullptr;
     return AssociatedFn->arg_begin() + ArgNo;
   }
-  const Argument *getAssociatedArgument() const {
-    return const_cast<IRPosition *>(this)->getAssociatedArgument();
-  }
-  ///}
 
   /// Return true if the position refers to a function interface, that is the
   /// function scope, the function return, or an argumnt.
@@ -319,9 +301,7 @@ struct IRPosition {
   }
 
   /// Return the Function surrounding the anchor value.
-  ///
-  ///{
-  Function *getAnchorScope() {
+  Function *getAnchorScope() const {
     Value &V = getAnchorValue();
     if (isa<Function>(V))
       return &cast<Function>(V);
@@ -331,15 +311,9 @@ struct IRPosition {
       return cast<Instruction>(V).getFunction();
     return nullptr;
   }
-  const Function *getAnchorScope() const {
-    return const_cast<IRPosition *>(this)->getAnchorScope();
-  }
-  ///}
 
   /// Return the context instruction, if any.
-  ///
-  ///{
-  Instruction *getCtxI() {
+  Instruction *getCtxI() const {
     Value &V = getAnchorValue();
     if (auto *I = dyn_cast<Instruction>(&V))
       return I;
@@ -351,15 +325,9 @@ struct IRPosition {
         return &(F->getEntryBlock().front());
     return nullptr;
   }
-  const Instruction *getCtxI() const {
-    return const_cast<IRPosition *>(this)->getCtxI();
-  }
-  ///}
 
   /// Return the value this abstract attribute is associated with.
-  ///
-  ///{
-  Value &getAssociatedValue() {
+  Value &getAssociatedValue() const {
     assert(KindOrArgNo != IRP_INVALID &&
            "Invalid position does not have an associated value!");
     if (getArgNo() < 0 || isa<Argument>(AnchorVal))
@@ -367,10 +335,6 @@ struct IRPosition {
     assert(isa<CallBase>(AnchorVal) && "Expected a call base!");
     return *cast<CallBase>(AnchorVal)->getArgOperand(getArgNo());
   }
-  const Value &getAssociatedValue() const {
-    return const_cast<IRPosition *>(this)->getAssociatedValue();
-  }
-  ///}
 
   /// Return the argument number of the associated value if it is an argument or
   /// call site argument, otherwise a negative value.
@@ -449,7 +413,7 @@ struct IRPosition {
   }
 
   /// Remove the attribute of kind \p AKs existing in the IR at this position.
-  void removeAttrs(ArrayRef<Attribute::AttrKind> AKs) {
+  void removeAttrs(ArrayRef<Attribute::AttrKind> AKs) const {
     if (getPositionKind() == IRP_INVALID || getPositionKind() == IRP_FLOAT)
       return;
 
@@ -502,6 +466,7 @@ private:
   /// Verify internal invariants.
   void verify();
 
+protected:
   /// The value this position is anchored at.
   Value *AnchorVal;
 
@@ -785,7 +750,7 @@ struct Attributor {
                   "'AbstractAttribute'!");
     // Put the attribute in the lookup map structure and the container we use to
     // keep track of all attributes.
-    IRPosition &IRP = AA.getIRPosition();
+    const IRPosition &IRP = AA.getIRPosition();
     auto &KindToAbstractAttributeMap = AAMap[IRP];
     assert(!KindToAbstractAttributeMap.count(&AAType::ID) &&
            "Attribute already in map!");
@@ -1320,7 +1285,7 @@ private:
 /// Helper struct necessary as the modular build fails if the virtual method
 /// IRAttribute::manifest is defined in the Attributor.cpp.
 struct IRAttributeManifest {
-  static ChangeStatus manifestAttrs(Attributor &A, IRPosition &IRP,
+  static ChangeStatus manifestAttrs(Attributor &A, const IRPosition &IRP,
                                     const ArrayRef<Attribute> &DeducedAttrs);
 };
 
@@ -1383,11 +1348,7 @@ struct IRAttribute : public IRPosition, public Base {
   }
 
   /// Return an IR position, see struct IRPosition.
-  ///
-  ///{
-  IRPosition &getIRPosition() override { return *this; }
   const IRPosition &getIRPosition() const override { return *this; }
-  ///}
 };
 
 /// Base struct for all "concrete attribute" deductions.
@@ -1492,9 +1453,6 @@ protected:
   /// add statistics for them.
   virtual void trackStatistics() const = 0;
 
-  /// Return an IR position, see struct IRPosition.
-  virtual IRPosition &getIRPosition() = 0;
-
   /// The actual update/transfer function which has to be implemented by the
   /// derived classes.
   ///
@@ -1751,11 +1709,7 @@ struct AAIsDead : public StateWrapper<BooleanState, AbstractAttribute>,
   }
 
   /// Return an IR position, see struct IRPosition.
-  ///
-  ///{
-  IRPosition &getIRPosition() override { return *this; }
   const IRPosition &getIRPosition() const override { return *this; }
-  ///}
 
   /// Create an abstract attribute view for the position \p IRP.
   static AAIsDead &createForPosition(const IRPosition &IRP, Attributor &A);
@@ -1957,11 +1911,7 @@ struct AAValueSimplify : public StateWrapper<BooleanState, AbstractAttribute>,
   AAValueSimplify(const IRPosition &IRP) : IRPosition(IRP) {}
 
   /// Return an IR position, see struct IRPosition.
-  ///
-  ///{
-  IRPosition &getIRPosition() { return *this; }
   const IRPosition &getIRPosition() const { return *this; }
-  ///}
 
   /// Return an assumed simplified value if a single candidate is found. If
   /// there cannot be one, return original value. If it is not clear yet, return
@@ -1987,11 +1937,7 @@ struct AAHeapToStack : public StateWrapper<BooleanState, AbstractAttribute>,
   bool isKnownHeapToStack() const { return getKnown(); }
 
   /// Return an IR position, see struct IRPosition.
-  ///
-  ///{
-  IRPosition &getIRPosition() { return *this; }
   const IRPosition &getIRPosition() const { return *this; }
-  ///}
 
   /// Create an abstract attribute view for the position \p IRP.
   static AAHeapToStack &createForPosition(const IRPosition &IRP, Attributor &A);

diff --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index a811471..b397f5a 100644 (file)
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -328,7 +328,7 @@ ChangeStatus AbstractAttribute::update(Attributor &A) {
 }
 
 ChangeStatus
-IRAttributeManifest::manifestAttrs(Attributor &A, IRPosition &IRP,
+IRAttributeManifest::manifestAttrs(Attributor &A, const IRPosition &IRP,
                                    const ArrayRef<Attribute> &DeducedAttrs) {
   Function *ScopeFn = IRP.getAssociatedFunction();
   IRPosition::Kind PK = IRP.getPositionKind();
@@ -705,7 +705,7 @@ struct AAFromMustBeExecutedContext : public Base {
 
   void initialize(Attributor &A) override {
     Base::initialize(A);
-    IRPosition &IRP = this->getIRPosition();
+    const IRPosition &IRP = this->getIRPosition();
     Instruction *CtxI = IRP.getCtxI();
 
     if (!CtxI)
@@ -987,7 +987,9 @@ ChangeStatus AAReturnedValuesImpl::manifest(Attributor &A) {
 
   // If the assumed unique return value is an argument, annotate it.
   if (auto *UniqueRVArg = dyn_cast<Argument>(UniqueRV.getValue())) {
-    getIRPosition() = IRPosition::argument(*UniqueRVArg);
+    // TODO: This should be handled differently!
+    this->AnchorVal = UniqueRVArg;
+    this->KindOrArgNo = UniqueRVArg->getArgNo();
     Changed = IRAttribute::manifest(A);
   } else if (auto *RVC = dyn_cast<Constant>(UniqueRV.getValue())) {
     // We can replace the returned value with the unique returned constant.
@@ -3816,7 +3818,7 @@ struct AAMemoryBehaviorImpl : public AAMemoryBehavior {
 
   /// See AbstractAttribute::manifest(...).
   ChangeStatus manifest(Attributor &A) override {
-    IRPosition &IRP = getIRPosition();
+    const IRPosition &IRP = getIRPosition();
 
     // Check if we would improve the existing attributes first.
     SmallVector<Attribute, 4> DeducedAttrs;