mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-10-25 14:02:52 +02:00
2e896f4f08
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 llvm-svn: 242963
93 lines
3.2 KiB
C++
93 lines
3.2 KiB
C++
//===- NoAliasAnalysis.cpp - Minimal Alias Analysis Impl ------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file defines the default implementation of the Alias Analysis interface
|
|
// that simply returns "I don't know" for all queries.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Analysis/Passes.h"
|
|
#include "llvm/Analysis/AliasAnalysis.h"
|
|
#include "llvm/IR/DataLayout.h"
|
|
#include "llvm/IR/LLVMContext.h"
|
|
#include "llvm/IR/Module.h"
|
|
#include "llvm/Pass.h"
|
|
using namespace llvm;
|
|
|
|
namespace {
|
|
/// NoAA - This class implements the -no-aa pass, which always returns "I
|
|
/// don't know" for alias queries. NoAA is unlike other alias analysis
|
|
/// implementations, in that it does not chain to a previous analysis. As
|
|
/// such it doesn't follow many of the rules that other alias analyses must.
|
|
///
|
|
struct NoAA : public ImmutablePass, public AliasAnalysis {
|
|
static char ID; // Class identification, replacement for typeinfo
|
|
NoAA() : ImmutablePass(ID) {
|
|
initializeNoAAPass(*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
void getAnalysisUsage(AnalysisUsage &AU) const override {}
|
|
|
|
bool doInitialization(Module &M) override {
|
|
// Note: NoAA does not call InitializeAliasAnalysis because it's
|
|
// special and does not support chaining.
|
|
DL = &M.getDataLayout();
|
|
return true;
|
|
}
|
|
|
|
AliasResult alias(const MemoryLocation &LocA,
|
|
const MemoryLocation &LocB) override {
|
|
return MayAlias;
|
|
}
|
|
|
|
FunctionModRefBehavior getModRefBehavior(ImmutableCallSite CS) override {
|
|
return FMRB_UnknownModRefBehavior;
|
|
}
|
|
FunctionModRefBehavior getModRefBehavior(const Function *F) override {
|
|
return FMRB_UnknownModRefBehavior;
|
|
}
|
|
|
|
bool pointsToConstantMemory(const MemoryLocation &Loc,
|
|
bool OrLocal) override {
|
|
return false;
|
|
}
|
|
ModRefInfo getArgModRefInfo(ImmutableCallSite CS,
|
|
unsigned ArgIdx) override {
|
|
return MRI_ModRef;
|
|
}
|
|
|
|
ModRefInfo getModRefInfo(ImmutableCallSite CS,
|
|
const MemoryLocation &Loc) override {
|
|
return MRI_ModRef;
|
|
}
|
|
ModRefInfo getModRefInfo(ImmutableCallSite CS1,
|
|
ImmutableCallSite CS2) override {
|
|
return MRI_ModRef;
|
|
}
|
|
|
|
/// getAdjustedAnalysisPointer - 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 *ID) override {
|
|
if (ID == &AliasAnalysis::ID)
|
|
return (AliasAnalysis*)this;
|
|
return this;
|
|
}
|
|
};
|
|
} // End of anonymous namespace
|
|
|
|
// Register this pass...
|
|
char NoAA::ID = 0;
|
|
INITIALIZE_AG_PASS(NoAA, AliasAnalysis, "no-aa",
|
|
"No Alias Analysis (always returns 'may' alias)",
|
|
true, true, true)
|
|
|
|
ImmutablePass *llvm::createNoAAPass() { return new NoAA(); }
|