Integrate the readonly/readnone logic more deeply
into alias analysis. This meant updating the API
which now has versions of the getModRefBehavior,
doesNotAccessMemory and onlyReadsMemory methods
which take a callsite parameter. These should be
used unless the callsite is not known, since in
general they can do a better job than the versions
that take a function. Also, users should no longer
call the version of getModRefBehavior that takes
both a function and a callsite. To reduce the
chance of misuse it is now protected.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44487 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/AliasAnalysis.cpp b/lib/Analysis/AliasAnalysis.cpp
index 2a3ac5a..9e1ae2a 100644
--- a/lib/Analysis/AliasAnalysis.cpp
+++ b/lib/Analysis/AliasAnalysis.cpp
@@ -27,6 +27,7 @@
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Pass.h"
#include "llvm/BasicBlock.h"
+#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/Type.h"
#include "llvm/Target/TargetData.h"
@@ -112,16 +113,40 @@
return pointsToConstantMemory(P) ? NoModRef : Mod;
}
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(CallSite CS,
+ std::vector<PointerAccessInfo> *Info) {
+ if (CS.paramHasAttr(0, ParamAttr::ReadNone))
+ // Can't do better than this.
+ return DoesNotAccessMemory;
+ ModRefBehavior MRB = UnknownModRefBehavior;
+ if (Function *F = CS.getCalledFunction())
+ MRB = getModRefBehavior(F, CS, Info);
+ if (MRB != DoesNotAccessMemory && CS.paramHasAttr(0, ParamAttr::ReadOnly))
+ return OnlyReadsMemory;
+ return MRB;
+}
+
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(Function *F,
+ std::vector<PointerAccessInfo> *Info) {
+ if (F->paramHasAttr(0, ParamAttr::ReadNone))
+ // Can't do better than this.
+ return DoesNotAccessMemory;
+ ModRefBehavior MRB = getModRefBehavior(F, CallSite(), Info);
+ if (MRB != DoesNotAccessMemory && F->paramHasAttr(0, ParamAttr::ReadOnly))
+ return OnlyReadsMemory;
+ return MRB;
+}
+
AliasAnalysis::ModRefResult
AliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
ModRefResult Mask = ModRef;
- if (Function *F = CS.getCalledFunction()) {
- ModRefBehavior MRB = getModRefBehavior(F, CallSite());
- if (MRB == OnlyReadsMemory)
- Mask = Ref;
- else if (MRB == DoesNotAccessMemory)
- return NoModRef;
- }
+ ModRefBehavior MRB = getModRefBehavior(CS);
+ if (MRB == OnlyReadsMemory)
+ Mask = Ref;
+ else if (MRB == DoesNotAccessMemory)
+ return NoModRef;
if (!AA) return Mask;