[Attributor][NFC] Expose new API in AAPointerInfo

New users might want to check bins without a load or store instruction
at hand. Since we use those instructions only to find the offset and
size of the access anyway, we can expose an offset and size interface
to the outside world as well.

This commit mainly moves code around and exposes a class (OffsetAndSize)
as well as a method forallInterferingAccesses in AAPointerInfo.

Differential Revision: https://reviews.llvm.org/D119249

Author: jdoerfert

llvm/include/llvm/Transforms/IPO/Attributor.h

@@ -4792,6 +4792,48 @@ struct AAPointerInfo : public AbstractAttribute {
   /// See AbstractAttribute::getIdAddr()
   const char *getIdAddr() const override { return &ID; }
 
+  /// Helper to represent an access offset and size, with logic to deal with
+  /// uncertainty and check for overlapping accesses.
+  struct OffsetAndSize : public std::pair<int64_t, int64_t> {
+    using BaseTy = std::pair<int64_t, int64_t>;
+    OffsetAndSize(int64_t Offset, int64_t Size) : BaseTy(Offset, Size) {}
+    OffsetAndSize(const BaseTy &P) : BaseTy(P) {}
+    int64_t getOffset() const { return first; }
+    int64_t getSize() const { return second; }
+    static OffsetAndSize getUnknown() {
+      return OffsetAndSize(Unknown, Unknown);
+    }
+
+    /// Return true if offset or size are unknown.
+    bool offsetOrSizeAreUnknown() const {
+      return getOffset() == OffsetAndSize::Unknown ||
+             getSize() == OffsetAndSize::Unknown;
+    }
+
+    /// Return true if this offset and size pair might describe an address that
+    /// overlaps with \p OAS.
+    bool mayOverlap(const OffsetAndSize &OAS) const {
+      // Any unknown value and we are giving up -> overlap.
+      if (offsetOrSizeAreUnknown() || OAS.offsetOrSizeAreUnknown())
+        return true;
+
+      // Check if one offset point is in the other interval [offset,
+      // offset+size].
+      return OAS.getOffset() + OAS.getSize() > getOffset() &&
+             OAS.getOffset() < getOffset() + getSize();
+    }
+
+    /// Constant used to represent unknown offset or sizes.
+    static constexpr int64_t Unknown = 1 << 31;
+  };
+
+  /// Call \p CB on all accesses that might interfere with \p OAS and return
+  /// true if all such accesses were known and the callback returned true for
+  /// all of them, false otherwise. An access interferes with an offset-size
+  /// pair if it might read or write that memory region.
+  virtual bool forallInterferingAccesses(
+      OffsetAndSize OAS, function_ref<bool(const Access &, bool)> CB) const = 0;
+
   /// Call \p CB on all accesses that might interfere with \p LI and return true
   /// if all such accesses were known and the callback returned true for all of
   /// them, false otherwise.

llvm/lib/Transforms/IPO/AttributorAttributes.cpp

@@ -787,9 +787,6 @@ namespace llvm {
 namespace AA {
 namespace PointerInfo {
 
-/// An access kind description as used by AAPointerInfo.
-struct OffsetAndSize;
-
 struct State;
 
 } // namespace PointerInfo
@@ -807,7 +804,7 @@ struct DenseMapInfo<AAPointerInfo::Access> : DenseMapInfo<Instruction *> {
 
 /// Helper that allows OffsetAndSize as a key in a DenseMap.
 template <>
-struct DenseMapInfo<AA::PointerInfo ::OffsetAndSize>
+struct DenseMapInfo<AAPointerInfo ::OffsetAndSize>
     : DenseMapInfo<std::pair<int64_t, int64_t>> {};
 
 /// Helper for AA::PointerInfo::Acccess DenseMap/Set usage ignoring everythign
@@ -823,38 +820,6 @@ struct AccessAsInstructionInfo : DenseMapInfo<Instruction *> {
 
 } // namespace llvm
 
-/// Helper to represent an access offset and size, with logic to deal with
-/// uncertainty and check for overlapping accesses.
-struct AA::PointerInfo::OffsetAndSize : public std::pair<int64_t, int64_t> {
-  using BaseTy = std::pair<int64_t, int64_t>;
-  OffsetAndSize(int64_t Offset, int64_t Size) : BaseTy(Offset, Size) {}
-  OffsetAndSize(const BaseTy &P) : BaseTy(P) {}
-  int64_t getOffset() const { return first; }
-  int64_t getSize() const { return second; }
-  static OffsetAndSize getUnknown() { return OffsetAndSize(Unknown, Unknown); }
-
-  /// Return true if offset or size are unknown.
-  bool offsetOrSizeAreUnknown() const {
-    return getOffset() == OffsetAndSize::Unknown ||
-           getSize() == OffsetAndSize::Unknown;
-  }
-
-  /// Return true if this offset and size pair might describe an address that
-  /// overlaps with \p OAS.
-  bool mayOverlap(const OffsetAndSize &OAS) const {
-    // Any unknown value and we are giving up -> overlap.
-    if (offsetOrSizeAreUnknown() || OAS.offsetOrSizeAreUnknown())
-      return true;
-
-    // Check if one offset point is in the other interval [offset, offset+size].
-    return OAS.getOffset() + OAS.getSize() > getOffset() &&
-           OAS.getOffset() < getOffset() + getSize();
-  }
-
-  /// Constant used to represent unknown offset or sizes.
-  static constexpr int64_t Unknown = 1 << 31;
-};
-
 /// Implementation of the DenseMapInfo.
 ///
 ///{
@@ -988,14 +953,14 @@ struct AA::PointerInfo::State : public AbstractState {
   using Accesses = DenseSet<AAPointerInfo::Access, AccessAsInstructionInfo>;
 
   /// We store all accesses in bins denoted by their offset and size.
-  using AccessBinsTy = DenseMap<OffsetAndSize, Accesses>;
+  using AccessBinsTy = DenseMap<AAPointerInfo::OffsetAndSize, Accesses>;
 
   AccessBinsTy::const_iterator begin() const { return AccessBins.begin(); }
   AccessBinsTy::const_iterator end() const { return AccessBins.end(); }
 
 protected:
   /// The bins with all the accesses for the associated pointer.
-  DenseMap<OffsetAndSize, Accesses> AccessBins;
+  DenseMap<AAPointerInfo::OffsetAndSize, Accesses> AccessBins;
 
   /// Add a new access to the state at offset \p Offset and with size \p Size.
   /// The access is associated with \p I, writes \p Content (if anything), and
@@ -1006,7 +971,7 @@ struct AA::PointerInfo::State : public AbstractState {
                          AAPointerInfo::AccessKind Kind, Type *Ty,
                          Instruction *RemoteI = nullptr,
                          Accesses *BinPtr = nullptr) {
-    OffsetAndSize Key{Offset, Size};
+    AAPointerInfo::OffsetAndSize Key{Offset, Size};
     Accesses &Bin = BinPtr ? *BinPtr : AccessBins[Key];
     AAPointerInfo::Access Acc(&I, RemoteI ? RemoteI : &I, Content, Kind, Ty);
     // Check if we have an access for this instruction in this bin, if not,
@@ -1023,14 +988,34 @@ struct AA::PointerInfo::State : public AbstractState {
     return *It == Before ? ChangeStatus::UNCHANGED : ChangeStatus::CHANGED;
   }
 
+  /// See AAPointerInfo::forallInterferingAccesses.
+  bool forallInterferingAccesses(
+      AAPointerInfo::OffsetAndSize OAS,
+      function_ref<bool(const AAPointerInfo::Access &, bool)> CB) const {
+    if (!isValidState())
+      return false;
+
+    for (auto &It : AccessBins) {
+      AAPointerInfo::OffsetAndSize ItOAS = It.getFirst();
+      if (!OAS.mayOverlap(ItOAS))
+        continue;
+      bool IsExact = OAS == ItOAS && !OAS.offsetOrSizeAreUnknown();
+      for (auto &Access : It.getSecond())
+        if (!CB(Access, IsExact))
+          return false;
+    }
+    return true;
+  }
+
   /// See AAPointerInfo::forallInterferingAccesses.
   bool forallInterferingAccesses(
       Instruction &I,
       function_ref<bool(const AAPointerInfo::Access &, bool)> CB) const {
     if (!isValidState())
       return false;
+
     // First find the offset and size of I.
-    OffsetAndSize OAS(-1, -1);
+    AAPointerInfo::OffsetAndSize OAS(-1, -1);
     for (auto &It : AccessBins) {
       for (auto &Access : It.getSecond()) {
         if (Access.getRemoteInst() == &I) {
@@ -1041,21 +1026,13 @@ struct AA::PointerInfo::State : public AbstractState {
       if (OAS.getSize() != -1)
         break;
     }
+    // No access for I was found, we are done.
     if (OAS.getSize() == -1)
       return true;
 
     // Now that we have an offset and size, find all overlapping ones and use
     // the callback on the accesses.
-    for (auto &It : AccessBins) {
-      OffsetAndSize ItOAS = It.getFirst();
-      if (!OAS.mayOverlap(ItOAS))
-        continue;
-      bool IsExact = OAS == ItOAS && !OAS.offsetOrSizeAreUnknown();
-      for (auto &Access : It.getSecond())
-        if (!CB(Access, IsExact))
-          return false;
-    }
-    return true;
+    return forallInterferingAccesses(OAS, CB);
   }
 
 private:
@@ -1084,6 +1061,12 @@ struct AAPointerInfoImpl
     return AAPointerInfo::manifest(A);
   }
 
+  bool forallInterferingAccesses(
+      OffsetAndSize OAS,
+      function_ref<bool(const AAPointerInfo::Access &, bool)> CB)
+      const override {
+    return State::forallInterferingAccesses(OAS, CB);
+  }
   bool forallInterferingAccesses(
       LoadInst &LI, function_ref<bool(const AAPointerInfo::Access &, bool)> CB)
       const override {
@@ -1306,7 +1289,7 @@ struct AAPointerInfoFloating : public AAPointerInfoImpl {
   bool handleAccess(Attributor &A, Instruction &I, Value &Ptr,
                     Optional<Value *> Content, AccessKind Kind, int64_t Offset,
                     ChangeStatus &Changed, Type *Ty,
-                    int64_t Size = AA::PointerInfo::OffsetAndSize::Unknown) {
+                    int64_t Size = OffsetAndSize::Unknown) {
     using namespace AA::PointerInfo;
     // No need to find a size if one is given or the offset is unknown.
     if (Offset != OffsetAndSize::Unknown && Size == OffsetAndSize::Unknown &&
@@ -1322,7 +1305,7 @@ struct AAPointerInfoFloating : public AAPointerInfoImpl {
 
   /// Helper struct, will support ranges eventually.
   struct OffsetInfo {
-    int64_t Offset = AA::PointerInfo::OffsetAndSize::Unknown;
+    int64_t Offset = OffsetAndSize::Unknown;
 
     bool operator==(const OffsetInfo &OI) const { return Offset == OI.Offset; }
   };