make clients have to know how to call getCallSiteDependencyFrom

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

diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index 44119d7b6b782399ebeb24c6eae8ea49c21e7f7f..415766a5a15c4f31a6c862f4f2d2f6c5bce64bbd 100644 (file)
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -52,10 +52,11 @@ bool MemoryDependenceAnalysis::runOnFunction(Function &) {
 }
 
 
-/// getCallSiteDependency - Private helper for finding the local dependencies
-/// of a call site.
+/// getCallSiteDependencyFrom - Private helper for finding the local
+/// dependencies of a call site.
 MemDepResult MemoryDependenceAnalysis::
-getCallSiteDependency(CallSite CS, BasicBlock::iterator ScanIt, BasicBlock *BB) {
+getCallSiteDependencyFrom(CallSite CS, BasicBlock::iterator ScanIt,
+                          BasicBlock *BB) {
   // Walk backwards through the block, looking for dependencies
   while (ScanIt != BB->begin()) {
     Instruction *Inst = --ScanIt;
@@ -109,30 +110,41 @@ getCallSiteDependency(CallSite CS, BasicBlock::iterator ScanIt, BasicBlock *BB)
 MemDepResult MemoryDependenceAnalysis::
 getDependencyFrom(Instruction *QueryInst, BasicBlock::iterator ScanIt, 
                   BasicBlock *BB) {
+  // The first instruction in a block is always non-local.
+  if (ScanIt == BB->begin())
+    return MemDepResult::getNonLocal();
+  
   // Get the pointer value for which dependence will be determined
   Value *MemPtr = 0;
   uint64_t MemSize = 0;
-  bool MemVolatile = false;
   
-  if (StoreInst* S = dyn_cast<StoreInst>(QueryInst)) {
-    MemPtr = S->getPointerOperand();
-    MemSize = TD->getTypeStoreSize(S->getOperand(0)->getType());
-    MemVolatile = S->isVolatile();
-  } else if (LoadInst* LI = dyn_cast<LoadInst>(QueryInst)) {
+  if (StoreInst *SI = dyn_cast<StoreInst>(QueryInst)) {
+    // If this is a volatile store, don't mess around with it.  Just return the
+    // previous instruction as a clobber.
+    if (SI->isVolatile())
+      return MemDepResult::getClobber(--ScanIt);
+
+    MemPtr = SI->getPointerOperand();
+    MemSize = TD->getTypeStoreSize(SI->getOperand(0)->getType());
+  } else if (LoadInst *LI = dyn_cast<LoadInst>(QueryInst)) {
+    // If this is a volatile load, don't mess around with it.  Just return the
+    // previous instruction as a clobber.
+    if (LI->isVolatile())
+      return MemDepResult::getClobber(--ScanIt);
+    
     MemPtr = LI->getPointerOperand();
     MemSize = TD->getTypeStoreSize(LI->getType());
-    MemVolatile = LI->isVolatile();
-  } else if (VAArgInst* V = dyn_cast<VAArgInst>(QueryInst)) {
-    MemPtr = V->getOperand(0);
-    MemSize = TD->getTypeStoreSize(V->getType());
-  } else if (FreeInst* F = dyn_cast<FreeInst>(QueryInst)) {
-    MemPtr = F->getPointerOperand();
+  } else if (FreeInst *FI = dyn_cast<FreeInst>(QueryInst)) {
+    MemPtr = FI->getPointerOperand();
     // FreeInsts erase the entire structure, not just a field.
     MemSize = ~0UL;
+  } else if (isa<CallInst>(QueryInst) || isa<InvokeInst>(QueryInst)) {
+    assert(0 && "Should use getCallSiteDependencyFrom!");
+    return getCallSiteDependencyFrom(CallSite::get(QueryInst), ScanIt, BB);
   } else {
-    assert((isa<CallInst>(QueryInst) || isa<InvokeInst>(QueryInst)) &&
-            "Can only get dependency info for memory instructions!");
-    return getCallSiteDependency(CallSite::get(QueryInst), ScanIt, BB);
+    // Otherwise, this is a vaarg or non-memory instruction, just return a
+    // clobber dependency on the previous inst.
+    return MemDepResult::getClobber(--ScanIt);
   }
   
   // Walk backwards through the basic block, looking for dependencies
@@ -142,10 +154,6 @@ getDependencyFrom(Instruction *QueryInst, BasicBlock::iterator ScanIt,
     // Values depend on loads if the pointers are must aliased.  This means that
     // a load depends on another must aliased load from the same value.
     if (LoadInst *LI = dyn_cast<LoadInst>(Inst)) {
-      // If the access is volatile and this is volatile, return a dependence.
-      if (MemVolatile && LI->isVolatile())
-        return MemDepResult::getClobber(LI);
-      
       Value *Pointer = LI->getPointerOperand();
       uint64_t PointerSize = TD->getTypeStoreSize(LI->getType());
       
@@ -162,10 +170,6 @@ getDependencyFrom(Instruction *QueryInst, BasicBlock::iterator ScanIt,
     }
     
     if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) {
-      // If the access is volatile and this is volatile, return a dependence.
-      if (MemVolatile && SI->isVolatile())
-        return MemDepResult::getClobber(SI);
-      
       Value *Pointer = SI->getPointerOperand();
       uint64_t PointerSize = TD->getTypeStoreSize(SI->getOperand(0)->getType());
 
@@ -230,7 +234,11 @@ MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) {
   }
   
   // Do the scan.
-  LocalCache = getDependencyFrom(QueryInst, ScanPos, QueryInst->getParent());
+  if (!isa<CallInst>(QueryInst) && !isa<InvokeInst>(QueryInst))
+    LocalCache = getDependencyFrom(QueryInst, ScanPos, QueryInst->getParent());
+  else 
+    LocalCache = getCallSiteDependencyFrom(CallSite::get(QueryInst), ScanPos,
+                                           QueryInst->getParent());
   
   // Remember the result!
   if (Instruction *I = LocalCache.getInst())
@@ -338,7 +346,12 @@ MemoryDependenceAnalysis::getNonLocalDependency(Instruction *QueryInst) {
     }
     
     // Find out if this block has a local dependency for QueryInst.
-    MemDepResult Dep = getDependencyFrom(QueryInst, ScanPos, DirtyBB);
+    MemDepResult Dep;
+    if (!isa<CallInst>(QueryInst) && !isa<InvokeInst>(QueryInst))
+      Dep = getDependencyFrom(QueryInst, ScanPos, DirtyBB);
+    else 
+      Dep = getCallSiteDependencyFrom(CallSite::get(QueryInst), ScanPos,
+                                      DirtyBB);
     
     // If we had a dirty entry for the block, update it.  Otherwise, just add
     // a new entry.
@@ -365,6 +378,7 @@ MemoryDependenceAnalysis::getNonLocalDependency(Instruction *QueryInst) {
   return Cache;
 }
 
+
 /// removeInstruction - Remove an instruction from the dependence analysis,
 /// updating the dependence of instructions that previously depended on it.
 /// This method attempts to keep the cache coherent using the reverse map.