[PATCH] D70233: [WIP][Attributor] AAReachability Attribute

[pankaj gode via Phabricator via llvm-commits]

pgode updated this revision to Diff 230372.
pgode added a comment.

Updated the patch as per review comments.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D70233/new/

https://reviews.llvm.org/D70233

Files:
  llvm/include/llvm/Transforms/IPO/Attributor.h
  llvm/lib/Transforms/IPO/Attributor.cpp


Index: llvm/lib/Transforms/IPO/Attributor.cpp
===================================================================
--- llvm/lib/Transforms/IPO/Attributor.cpp
+++ llvm/lib/Transforms/IPO/Attributor.cpp
@@ -2051,6 +2051,34 @@
   void trackStatistics() const override { STATS_DECLTRACK_CS_ATTR(willreturn); }
 };
 
+/// -------------------AAReachability Attribute--------------------------
+
+struct AAReachabilityImpl : AAReachability {
+  AAReachabilityImpl(const IRPosition &IRP) : AAReachability(IRP) {}
+
+  const std::string getAsStr() const override {
+    // TODO: Return the number of reachable queries.
+    return "reachable";
+  }
+
+  /// See AbstractAttribute::initialize(...).
+  void initialize(Attributor &A) override {
+    indicatePessimisticFixpoint();
+  }
+
+  /// See AbstractAttribute::updateImpl(...).
+  ChangeStatus updateImpl(Attributor &A) override {
+    return indicatePessimisticFixpoint();
+  }
+};
+
+struct AAReachabilityFunction final : public AAReachabilityImpl {
+  AAReachabilityFunction(const IRPosition &IRP) : AAReachabilityImpl(IRP) {}
+
+  /// See AbstractAttribute::trackStatistics()
+  void trackStatistics() const override { STATS_DECLTRACK_FN_ATTR(reachable); }
+};
+
 /// ------------------------ NoAlias Argument Attribute ------------------------
 
 struct AANoAliasImpl : AANoAlias {
@@ -5684,6 +5712,7 @@
 const char AANoRecurse::ID = 0;
 const char AAWillReturn::ID = 0;
 const char AANoAlias::ID = 0;
+const char AAReachability::ID = 0;
 const char AANoReturn::ID = 0;
 const char AAIsDead::ID = 0;
 const char AADereferenceable::ID = 0;
@@ -5803,6 +5832,7 @@
 CREATE_ALL_ABSTRACT_ATTRIBUTE_FOR_POSITION(AANoFree)
 
 CREATE_FUNCTION_ONLY_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAHeapToStack)
+CREATE_FUNCTION_ONLY_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAReachability)
 
 CREATE_NON_RET_ABSTRACT_ATTRIBUTE_FOR_POSITION(AAMemoryBehavior)
 
Index: llvm/include/llvm/Transforms/IPO/Attributor.h
===================================================================
--- llvm/include/llvm/Transforms/IPO/Attributor.h
+++ llvm/include/llvm/Transforms/IPO/Attributor.h
@@ -1682,6 +1682,37 @@
   static const char ID;
 };
 
+/// An abstract interface to determine reachability of point A to B.
+struct AAReachability : public StateWrapper<BooleanState, AbstractAttribute>,
+                        public IRPosition {
+  AAReachability(const IRPosition &IRP) : IRPosition(IRP) {}
+
+  /// Returns true if 'From' instruction is assumed to reach, 'To' instruction.
+  /// Users should provide two positions they are interested in, and the class
+  /// determines (and caches) reachability.
+  bool isAssumedReachable(const Instruction *From,
+                          const Instruction *To) const {
+    return true;
+  }
+
+  /// Returns true if 'From' instruction is known to reach, 'To' instruction.
+  /// Users should provide two positions they are interested in, and the class
+  /// determines (and caches) reachability.
+  bool isKnownReachable(const Instruction *From, const Instruction *To) const {
+    return true;
+  }
+
+  /// Return an IR position, see struct IRPosition.
+  const IRPosition &getIRPosition() const override { return *this; }
+
+  /// Create an abstract attribute view for the position \p IRP.
+  static AAReachability &createForPosition(const IRPosition &IRP,
+                                           Attributor &A);
+
+  /// Unique ID (due to the unique address)
+  static const char ID;
+};
+
 /// An abstract interface for all noalias attributes.
 struct AANoAlias
     : public IRAttribute<Attribute::NoAlias,


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