Files
llvm-6502/lib/Transforms/ObjCARC/ObjCARCAliasAnalysis.h
Chandler Carruth 52ab0bc417 [PM/AA] Extract the ModRef enums from the AliasAnalysis class in
preparation for de-coupling the AA implementations.

In order to do this, they had to become fake-scoped using the
traditional LLVM pattern of a leading initialism. These can't be actual
scoped enumerations because they're bitfields and thus inherently we use
them as integers.

I've also renamed the behavior enums that are specific to reasoning
about the mod/ref behavior of functions when called. This makes it more
clear that they have a very narrow domain of applicability.

I think there is a significantly cleaner API for all of this, but
I don't want to try to do really substantive changes for now, I just
want to refactor the things away from analysis groups so I'm preserving
the exact original design and just cleaning up the names, style, and
lifting out of the class.

Differential Revision: http://reviews.llvm.org/D10564

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@242963 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-22 23:15:57 +00:00

75 lines
3.0 KiB
C++

//===- ObjCARCAliasAnalysis.h - ObjC ARC Optimization -*- C++ -*-----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
/// This file declares a simple ARC-aware AliasAnalysis using special knowledge
/// of Objective C to enhance other optimization passes which rely on the Alias
/// Analysis infrastructure.
///
/// WARNING: This file knows about certain library functions. It recognizes them
/// by name, and hardwires knowledge of their semantics.
///
/// WARNING: This file knows about how certain Objective-C library functions are
/// used. Naive LLVM IR transformations which would otherwise be
/// behavior-preserving may break these assumptions.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARCALIASANALYSIS_H
#define LLVM_LIB_TRANSFORMS_OBJCARC_OBJCARCALIASANALYSIS_H
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Pass.h"
namespace llvm {
namespace objcarc {
/// \brief This is a simple alias analysis implementation that uses knowledge
/// of ARC constructs to answer queries.
///
/// TODO: This class could be generalized to know about other ObjC-specific
/// tricks. Such as knowing that ivars in the non-fragile ABI are non-aliasing
/// even though their offsets are dynamic.
class ObjCARCAliasAnalysis : public ImmutablePass,
public AliasAnalysis {
public:
static char ID; // Class identification, replacement for typeinfo
ObjCARCAliasAnalysis() : ImmutablePass(ID) {
initializeObjCARCAliasAnalysisPass(*PassRegistry::getPassRegistry());
}
private:
bool doInitialization(Module &M) override;
/// This method is used when a pass implements an analysis interface through
/// multiple inheritance. If needed, it should override this to adjust the
/// this pointer as needed for the specified pass info.
void *getAdjustedAnalysisPointer(const void *PI) override {
if (PI == &AliasAnalysis::ID)
return static_cast<AliasAnalysis *>(this);
return this;
}
void getAnalysisUsage(AnalysisUsage &AU) const override;
AliasResult alias(const MemoryLocation &LocA,
const MemoryLocation &LocB) override;
bool pointsToConstantMemory(const MemoryLocation &Loc,
bool OrLocal) override;
FunctionModRefBehavior getModRefBehavior(ImmutableCallSite CS) override;
FunctionModRefBehavior getModRefBehavior(const Function *F) override;
ModRefInfo getModRefInfo(ImmutableCallSite CS,
const MemoryLocation &Loc) override;
ModRefInfo getModRefInfo(ImmutableCallSite CS1,
ImmutableCallSite CS2) override;
};
} // namespace objcarc
} // namespace llvm
#endif