removes a few "const" qualifiers

[oota-llvm.git] / lib / Analysis / MemoryDependenceAnalysis.cpp

diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index f80b4f8cdf2c84ee59f8e6c8f38b024af38ed688..9872890494556e61a132acce9e0defcd736c29f9 100644 (file)
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -30,7 +30,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/PredIteratorCache.h"
 #include "llvm/Support/Debug.h"
-#include "llvm/Target/TargetData.h"
+#include "llvm/DataLayout.h"
 using namespace llvm;
 
 STATISTIC(NumCacheNonLocal, "Number of fully cached non-local responses");
@@ -89,7 +89,7 @@ void MemoryDependenceAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
 
 bool MemoryDependenceAnalysis::runOnFunction(Function &) {
   AA = &getAnalysis<AliasAnalysis>();
-  TD = getAnalysisIfAvailable<TargetData>();
+  TD = getAnalysisIfAvailable<DataLayout>();
   DT = getAnalysisIfAvailable<DominatorTree>();
   if (PredCache == 0)
     PredCache.reset(new PredIteratorCache());
@@ -148,7 +148,7 @@ AliasAnalysis::ModRefResult GetLocation(const Instruction *Inst,
     return AliasAnalysis::ModRef;
   }
 
-  if (const CallInst *CI = isFreeCall(Inst)) {
+  if (const CallInst *CI = isFreeCall(Inst, AA->getTargetLibraryInfo())) {
     // calls to free() deallocate the entire structure
     Loc = AliasAnalysis::Location(CI->getArgOperand(0));
     return AliasAnalysis::Mod;
@@ -227,13 +227,18 @@ getCallSiteDependencyFrom(CallSite CS, bool isReadOnlyCall,
 
         // Otherwise if the two calls don't interact (e.g. InstCS is readnone)
         // keep scanning.
-        break;
+        continue;
       default:
         return MemDepResult::getClobber(Inst);
       }
     }
+
+    // If we could not obtain a pointer for the instruction and the instruction
+    // touches memory then assume that this is a dependency.
+    if (MR != AliasAnalysis::NoModRef)
+      return MemDepResult::getClobber(Inst);
   }
-  
+
   // No dependence found.  If this is the entry block of the function, it is
   // unknown, otherwise it is non-local.
   if (BB != &BB->getParent()->getEntryBlock())
@@ -251,7 +256,7 @@ isLoadLoadClobberIfExtendedToFullWidth(const AliasAnalysis::Location &MemLoc,
                                        const Value *&MemLocBase,
                                        int64_t &MemLocOffs,
                                        const LoadInst *LI,
-                                       const TargetData *TD) {
+                                       const DataLayout *TD) {
   // If we have no target data, we can't do this.
   if (TD == 0) return false;
 
@@ -275,7 +280,7 @@ isLoadLoadClobberIfExtendedToFullWidth(const AliasAnalysis::Location &MemLoc,
 unsigned MemoryDependenceAnalysis::
 getLoadLoadClobberFullWidthSize(const Value *MemLocBase, int64_t MemLocOffs,
                                 unsigned MemLocSize, const LoadInst *LI,
-                                const TargetData &TD) {
+                                const DataLayout &TD) {
   // We can only extend simple integer loads.
   if (!isa<IntegerType>(LI->getType()) || !LI->isSimple()) return 0;
   
@@ -322,12 +327,12 @@ getLoadLoadClobberFullWidthSize(const Value *MemLocBase, int64_t MemLocOffs,
       return 0;
 
     if (LIOffs+NewLoadByteSize > MemLocEnd &&
-        LI->getParent()->getParent()->hasFnAttr(Attribute::AddressSafety)) {
+        LI->getParent()->getParent()->getFnAttributes().
+          hasAttribute(Attributes::AddressSafety))
       // We will be reading past the location accessed by the original program.
       // While this is safe in a regular build, Address Safety analysis tools
       // may start reporting false warnings. So, don't do widening.
       return 0;
-    }
 
     // If a load of this width would include all of MemLoc, then we succeed.
     if (LIOffs+NewLoadByteSize >= MemLocEnd)
@@ -474,13 +479,20 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad,
     // a subsequent bitcast of the malloc call result.  There can be stores to
     // the malloced memory between the malloc call and its bitcast uses, and we
     // need to continue scanning until the malloc call.
-    if (isa<AllocaInst>(Inst) ||
-        (isa<CallInst>(Inst) && extractMallocCall(Inst))) {
+    const TargetLibraryInfo *TLI = AA->getTargetLibraryInfo();
+    if (isa<AllocaInst>(Inst) || isNoAliasFn(Inst, TLI)) {
       const Value *AccessPtr = GetUnderlyingObject(MemLoc.Ptr, TD);
       
       if (AccessPtr == Inst || AA->isMustAlias(Inst, AccessPtr))
         return MemDepResult::getDef(Inst);
-      continue;
+      // Be conservative if the accessed pointer may alias the allocation.
+      if (AA->alias(Inst, AccessPtr) != AliasAnalysis::NoAlias)
+        return MemDepResult::getClobber(Inst);
+      // If the allocation is not aliased and does not read memory (like
+      // strdup), it is safe to ignore.
+      if (isa<AllocaInst>(Inst) ||
+          isMallocLikeFn(Inst, TLI) || isCallocLikeFn(Inst, TLI))
+        continue;
     }
 
     // See if this instruction (e.g. a call or vaarg) mod/ref's the pointer.
@@ -906,7 +918,7 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer,
   if (!Pair.second) {
     if (CacheInfo->Size < Loc.Size) {
       // The query's Size is greater than the cached one. Throw out the
-      // cached data and procede with the query at the greater size.
+      // cached data and proceed with the query at the greater size.
       CacheInfo->Pair = BBSkipFirstBlockPair();
       CacheInfo->Size = Loc.Size;
       for (NonLocalDepInfo::iterator DI = CacheInfo->NonLocalDeps.begin(),
@@ -971,7 +983,7 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer,
     for (NonLocalDepInfo::iterator I = Cache->begin(), E = Cache->end();
          I != E; ++I) {
       Visited.insert(std::make_pair(I->getBB(), Addr));
-      if (!I->getResult().isNonLocal())
+      if (!I->getResult().isNonLocal() && DT->isReachableFromEntry(I->getBB()))
         Result.push_back(NonLocalDepResult(I->getBB(), I->getResult(), Addr));
     }
     ++NumCacheCompleteNonLocalPtr;
@@ -1017,7 +1029,7 @@ getNonLocalPointerDepFromBB(const PHITransAddr &Pointer,
                                                  NumSortedEntries);
       
       // If we got a Def or Clobber, add this to the list of results.
-      if (!Dep.isNonLocal()) {
+      if (!Dep.isNonLocal() && DT->isReachableFromEntry(BB)) {
         Result.push_back(NonLocalDepResult(BB, Dep, Pointer.getAddr()));
         continue;
       }