+ /// These values define additional bits used to define the
+ /// ModRefBehavior values.
+ enum { Nowhere = 0, ArgumentPointees = 4, Anywhere = 8 | ArgumentPointees };
+
+ /// ModRefBehavior - Summary of how a function affects memory in the program.
+ /// Loads from constant globals are not considered memory accesses for this
+ /// interface. Also, functions may freely modify stack space local to their
+ /// invocation without having to report it through these interfaces.
+ enum ModRefBehavior {
+ /// DoesNotAccessMemory - This function does not perform any non-local loads
+ /// or stores to memory.
+ ///
+ /// This property corresponds to the GCC 'const' attribute.
+ /// This property corresponds to the LLVM IR 'readnone' attribute.
+ /// This property corresponds to the IntrNoMem LLVM intrinsic flag.
+ DoesNotAccessMemory = Nowhere | NoModRef,
+
+ /// OnlyReadsArgumentPointees - The only memory references in this function
+ /// (if it has any) are non-volatile loads from objects pointed to by its
+ /// pointer-typed arguments, with arbitrary offsets.
+ ///
+ /// This property corresponds to the IntrReadArgMem LLVM intrinsic flag.
+ OnlyReadsArgumentPointees = ArgumentPointees | Ref,
+
+ /// OnlyAccessesArgumentPointees - The only memory references in this
+ /// function (if it has any) are non-volatile loads and stores from objects
+ /// pointed to by its pointer-typed arguments, with arbitrary offsets.
+ ///
+ /// This property corresponds to the IntrReadWriteArgMem LLVM intrinsic flag.
+ OnlyAccessesArgumentPointees = ArgumentPointees | ModRef,
+
+ /// OnlyReadsMemory - This function does not perform any non-local stores or
+ /// volatile loads, but may read from any memory location.
+ ///
+ /// This property corresponds to the GCC 'pure' attribute.
+ /// This property corresponds to the LLVM IR 'readonly' attribute.
+ /// This property corresponds to the IntrReadMem LLVM intrinsic flag.
+ OnlyReadsMemory = Anywhere | Ref,
+
+ /// UnknownModRefBehavior - This indicates that the function could not be
+ /// classified into one of the behaviors above.
+ UnknownModRefBehavior = Anywhere | ModRef
+ };
+
+ /// getModRefBehavior - Return the behavior when calling the given call site.
+ virtual ModRefBehavior getModRefBehavior(ImmutableCallSite CS);
+
+ /// getModRefBehavior - Return the behavior when calling the given function.
+ /// For use when the call site is not known.
+ virtual ModRefBehavior getModRefBehavior(const Function *F);
+
+ /// doesNotAccessMemory - If the specified call is known to never read or
+ /// write memory, return true. If the call only reads from known-constant
+ /// memory, it is also legal to return true. Calls that unwind the stack
+ /// are legal for this predicate.