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Implement getModRefInfo() for DSA to calculate whether a function modifies or

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references a pointer.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12330 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Misha Brukman 2004-03-12 06:14:22 +00:00
parent 8e18789ede
commit a975a9ab80
1 changed files with 39 additions and 5 deletions
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44
lib/Analysis/DataStructure/DataStructureAA.cpp
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@ -12,15 +12,16 @@
//
//===----------------------------------------------------------------------===//
#include "llvm/Module.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/DataStructure.h"
#include "llvm/Analysis/DSGraph.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Module.h"
using namespace llvm;
namespace {
class DSAA : public Pass, public AliasAnalysis {
TDDataStructures *TD;
BUDataStructures *BU;
public:
DSAA() : TD(0) {}
@ -34,14 +35,16 @@ namespace {
bool run(Module &M) {
InitializeAliasAnalysis(this);
TD = &getAnalysis<TDDataStructures>();
BU = &getAnalysis<BUDataStructures>();
return false;
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AliasAnalysis::getAnalysisUsage(AU);
AU.setPreservesAll(); // Does not transform code...
AU.addRequired<TDDataStructures>(); // Uses TD Datastructures
AU.addRequired<AliasAnalysis>(); // Chains to another AA impl...
AU.setPreservesAll(); // Does not transform code
AU.addRequiredTransitive<TDDataStructures>(); // Uses TD Datastructures
AU.addRequiredTransitive<BUDataStructures>(); // Uses BU Datastructures
AU.addRequired<AliasAnalysis>(); // Chains to another AA impl
}
//------------------------------------------------
@ -56,6 +59,9 @@ namespace {
bool pointsToConstantMemory(const Value *P) {
return getAnalysis<AliasAnalysis>().pointsToConstantMemory(P);
}
AliasAnalysis::ModRefResult
getModRefInfo(CallSite CS, Value *P, unsigned Size);
private:
DSGraph *getGraphForValue(const Value *V);
@ -152,6 +158,34 @@ AliasAnalysis::AliasResult DSAA::alias(const Value *V1, unsigned V1Size,
return getAnalysis<AliasAnalysis>().alias(V1, V1Size, V2, V2Size);
}
/// getModRefInfo - does a callsite modify or reference a value?
///
AliasAnalysis::ModRefResult
DSAA::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
Function *F = CS.getCalledFunction();
if (!F) return pointsToConstantMemory(P) ? Ref : ModRef;
if (F->isExternal()) return ModRef;
// Clone the function TD graph, clearing off Mod/Ref flags
const Function *csParent = CS.getInstruction()->getParent()->getParent();
DSGraph TDGraph(TD->getDSGraph(*csParent));
TDGraph.maskNodeTypes(0);
// Insert the callee's BU graph into the TD graph
const DSGraph &BUGraph = BU->getDSGraph(*F);
TDGraph.mergeInGraph(TDGraph.getDSCallSiteForCallSite(CS),
*F, BUGraph, 0);
// Report the flags that have been added
const DSNodeHandle &DSH = TDGraph.getNodeForValue(P);
if (const DSNode *N = DSH.getNode())
if (N->isModified())
return N->isRead() ? ModRef : Mod;
else
return N->isRead() ? Ref : NoModRef;
return NoModRef;
}
/// getMustAliases - If there are any pointers known that must alias this
/// pointer, return them now. This allows alias-set based alias analyses to