SIL: improve comments for the mayRead/mayWrite APIs in SILInstruction and AliasAnalysis

Author: eeckstein

include/swift/SIL/SILInstruction.h

@@ -622,14 +622,19 @@ class SILInstruction
 
   /// Returns true if the instruction may write to memory, deinitialize memory,
   /// or have other unknown side effects.
+  ///
+  /// For details see SILInstruction::MemoryBehavior.
   bool mayWriteToMemory() const {
     MemoryBehavior B = getMemoryBehavior();
     return B == MemoryBehavior::MayWrite ||
       B == MemoryBehavior::MayReadWrite ||
       B == MemoryBehavior::MayHaveSideEffects;
   }
 
-  /// Returns true if the instruction may read from memory.
+  /// Returns true if the instruction may read from memory, or have other
+  /// unknown side effects.
+  ///
+  /// For details see SILInstruction::MemoryBehavior.
   bool mayReadFromMemory() const {
     MemoryBehavior B = getMemoryBehavior();
     return B == MemoryBehavior::MayRead ||
@@ -639,6 +644,8 @@ class SILInstruction
 
   /// Returns true if the instruction may read from memory, write to memory,
   /// deinitialize memory, or have other unknown side effects.
+  ///
+  /// For details see SILInstruction::MemoryBehavior.
   bool mayReadOrWriteMemory() const {
     return getMemoryBehavior() != MemoryBehavior::None;
   }

include/swift/SILOptimizer/Analysis/AliasAnalysis.h

@@ -215,26 +215,31 @@ class AliasAnalysis : public SILAnalysis {
   /// respect to V.
   MemoryBehavior computeMemoryBehaviorInner(SILInstruction *Inst, SILValue V);
 
-  /// Returns true if \p Inst may read from memory in a manner that
-  /// affects V.
+  /// Returns true if \p Inst may read from memory at address \p V.
+  ///
+  /// For details see SILInstruction::MemoryBehavior::MayRead.
   bool mayReadFromMemory(SILInstruction *Inst, SILValue V) {
     auto B = computeMemoryBehavior(Inst, V);
     return B == MemoryBehavior::MayRead ||
            B == MemoryBehavior::MayReadWrite ||
            B == MemoryBehavior::MayHaveSideEffects;
   }
 
-  /// Returns true if \p Inst may write to memory, deinitialize memory, or have
-  /// other side effects that may affect V.
+  /// Returns true if \p Inst may write to memory or deinitialize memory at
+  /// address \p V.
+  ///
+  /// For details see SILInstruction::MemoryBehavior::MayWrite.
   bool mayWriteToMemory(SILInstruction *Inst, SILValue V) {
     auto B = computeMemoryBehavior(Inst, V);
     return B == MemoryBehavior::MayWrite ||
            B == MemoryBehavior::MayReadWrite ||
            B == MemoryBehavior::MayHaveSideEffects;
   }
 
-  /// Returns true if \p Inst may read to memory, write to memory, deinitialize
-  /// memory, or have other side effects that may affect V.
+  /// Returns true if \p Inst may read from memory, write to memory or
+  /// deinitialize memory at address \p V.
+  ///
+  /// For details see SILInstruction::MemoryBehavior.
   bool mayReadOrWriteMemory(SILInstruction *Inst, SILValue V) {
     auto B = computeMemoryBehavior(Inst, V);
     return MemoryBehavior::None != B;