New general purpose alias analysis result auditor

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5503 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/AliasAnalysisCounter.cpp

@@ -0,0 +1,64 @@
+//===- AliasAnalysisCounter.cpp - Alias Analysis Query Counter ------------===//
+//
+// This file implements a pass which can be used to count how many alias queries
+// are being made and how the alias analysis implementation being used responds.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Pass.h"
+#include <iostream>
+
+namespace {
+  unsigned No = 0, May = 0, Must = 0;
+
+  struct AliasAnalysisCounter : public Pass, public AliasAnalysis {
+    bool run(Module &M) { return false; }
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.addRequired<AliasAnalysis>();
+      AU.setPreservesAll();
+    }
+
+    Result count(Result R) {
+      switch (R) {
+      default: assert(0 && "Unknown alias type!");
+      case NoAlias:   No++; return NoAlias;
+      case MayAlias:  May++; return MayAlias;
+      case MustAlias: Must++; return MustAlias;
+      }
+    }
+    
+    // Forwarding functions: just delegate to a real AA implementation, counting
+    // the number of responses...
+    Result alias(const Value *V1, const Value *V2) {
+      return count(getAnalysis<AliasAnalysis>().alias(V1, V2));
+    }
+    Result canCallModify(const CallInst &CI, const Value *Ptr) {
+      return count(getAnalysis<AliasAnalysis>().canCallModify(CI, Ptr));
+    }
+    Result canInvokeModify(const InvokeInst &I, const Value *Ptr) {
+      return count(getAnalysis<AliasAnalysis>().canInvokeModify(I, Ptr));
+    }
+  };
+
+  RegisterOpt<AliasAnalysisCounter>
+  X("count-aa", "Count Alias Analysis Query Responses");
+  RegisterAnalysisGroup<AliasAnalysis, AliasAnalysisCounter> Y;
+
+
+  struct ResultPrinter {
+    ~ResultPrinter() {
+      unsigned Sum = No+May+Must;
+      if (Sum) {            // Print a report if any counted queries occurred...
+        std::cerr
+          << "\n===== Alias Analysis Counter Report =====\n"
+          << "  " << Sum << " Total Alias Queries Performed\n"
+          << "  " << No << " no alias responses (" << No*100/Sum << "%)\n"
+          << "  " << May << " may alias responses (" << May*100/Sum << "%)\n"
+          << "  " << Must << " must alias responses (" <<Must*100/Sum<<"%)\n"
+          << "  Alias Analysis Counter Summary: " << No*100/Sum << "%/"
+          << May*100/Sum << "%/" << Must*100/Sum<<"%\n\n";
+      }
+    }
+  } RP;
+}