Implement getModRefInfo() for DSA to calculate whether a function modifies or
references a pointer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12330 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/DataStructure/DataStructureAA.cpp b/lib/Analysis/DataStructure/DataStructureAA.cpp
index 1f24470..152e53c 100644
--- a/lib/Analysis/DataStructure/DataStructureAA.cpp
+++ b/lib/Analysis/DataStructure/DataStructureAA.cpp
@@ -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 @@
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 @@
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 @@
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