A shim over other AA impls to catch incorrect uses

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31724 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 125 insertions, 0 deletions

diff --git a/lib/Analysis/AliasDebugger.cpp b/lib/Analysis/AliasDebugger.cpp
new file mode 100644
index 0000000000..ddbb7bde4c
--- /dev/null
+++ b/lib/Analysis/AliasDebugger.cpp
@@ -0,0 +1,125 @@
+//===- AliasDebugger.cpp - Simple Alias Analysis Use Checker --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Andrew Lenharth and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This simple pass checks alias analysis users to ensure that if they
+// create a new value, they do not query AA without informing it of the value.
+// It acts as a shim over any other AA pass you want.
+//
+// Yes keeping track of every value in the program is expensive, but this is 
+// a debugging pass.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/Passes.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Instructions.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include <set>
+using namespace llvm;
+
+namespace {
+  
+  class AliasDebugger : public ModulePass, public AliasAnalysis {
+
+    //What we do is simple.  Keep track of every value the AA could
+    //know about, and verify that queries are one of those.
+    //A query to a value that didn't exist when the AA was created
+    //means someone forgot to update the AA when creating new values
+
+    std::set<const Value*> Vals;
+    
+  public:
+    bool runOnModule(Module &M) {
+      InitializeAliasAnalysis(this);                 // set up super class
+
+      for(Module::global_iterator I = M.global_begin(),
+            E = M.global_end(); I != E; ++I)
+        Vals.insert(&*I);
+
+      for(Module::iterator I = M.begin(),
+            E = M.end(); I != E; ++I){
+        Vals.insert(&*I);
+        if(!I->isExternal()) {
+          for (Function::arg_iterator AI = I->arg_begin(), AE = I->arg_end();
+               AI != AE; ++AI) 
+            Vals.insert(&*AI);     
+          for (Function::const_iterator FI = I->begin(), FE = I->end();
+               FI != FE; ++FI) 
+            for (BasicBlock::const_iterator BI = FI->begin(), BE = FI->end();
+                 BI != BE; ++BI)
+              Vals.insert(&*BI);
+        }
+        
+      }
+      return false;
+    }
+
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AliasAnalysis::getAnalysisUsage(AU);
+      AU.setPreservesAll();                         // Does not transform code
+    }
+
+    //------------------------------------------------
+    // Implement the AliasAnalysis API
+    //
+    AliasResult alias(const Value *V1, unsigned V1Size,
+                      const Value *V2, unsigned V2Size) {
+      assert(Vals.find(V1) != Vals.end() && "Never seen value in AA before");
+      assert(Vals.find(V2) != Vals.end() && "Never seen value in AA before");    
+      return AliasAnalysis::alias(V1, V1Size, V2, V2Size);
+    }
+
+    ModRefResult getModRefInfo(CallSite CS, Value *P, unsigned Size) {
+      assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
+      return AliasAnalysis::getModRefInfo(CS, P, Size);
+    }
+
+    ModRefResult getModRefInfo(CallSite CS1, CallSite CS2) {
+      return AliasAnalysis::getModRefInfo(CS1,CS2);
+    }
+    
+    void getMustAliases(Value *P, std::vector<Value*> &RetVals) {
+      assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
+      return AliasAnalysis::getMustAliases(P, RetVals);
+    }
+
+    bool pointsToConstantMemory(const Value *P) {
+      assert(Vals.find(P) != Vals.end() && "Never seen value in AA before");
+      return AliasAnalysis::pointsToConstantMemory(P);
+    }
+
+    /// getModRefBehavior - Return the behavior of the specified function if
+    /// called from the specified call site.  The call site may be null in which
+    /// case the most generic behavior of this function should be returned.
+    virtual ModRefBehavior getModRefBehavior(Function *F, CallSite CS,
+                                         std::vector<PointerAccessInfo> *Info) {
+      assert(Vals.find(F) != Vals.end() && "Never seen value in AA before");
+      return AliasAnalysis::getModRefBehavior(F, CS, Info);
+    }
+
+    virtual void deleteValue(Value *V) {
+      assert(Vals.find(V) != Vals.end() && "Never seen value in AA before");
+      AliasAnalysis::deleteValue(V);
+    }
+    virtual void copyValue(Value *From, Value *To) {
+      Vals.insert(To);
+      AliasAnalysis::copyValue(From, To);
+    }
+
+  };
+
+  RegisterPass<AliasDebugger> X("debug-aa", "AA use debugger");
+  RegisterAnalysisGroup<AliasAnalysis> Y(X);
+}
+
+Pass *llvm::createAliasDebugger() { return new AliasDebugger(); }
+