1 files changed, 249 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Analysis/AliasAnalysis.cpp b/contrib/llvm/lib/Analysis/AliasAnalysis.cpp
new file mode 100644
index 0000000..371dcaf
--- /dev/null
+++ b/contrib/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -0,0 +1,249 @@
+//===- AliasAnalysis.cpp - Generic Alias Analysis Interface Implementation -==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the generic AliasAnalysis interface which is used as the
+// common interface used by all clients and implementations of alias analysis.
+//
+// This file also implements the default version of the AliasAnalysis interface
+// that is to be used when no other implementation is specified.  This does some
+// simple tests that detect obvious cases: two different global pointers cannot
+// alias, a global cannot alias a malloc, two different mallocs cannot alias,
+// etc.
+//
+// This alias analysis implementation really isn't very good for anything, but
+// it is very fast, and makes a nice clean default implementation.  Because it
+// handles lots of little corner cases, other, more complex, alias analysis
+// implementations may choose to rely on this pass to resolve these simple and
+// easy cases.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Pass.h"
+#include "llvm/BasicBlock.h"
+#include "llvm/Function.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/Instructions.h"
+#include "llvm/Type.h"
+#include "llvm/Target/TargetData.h"
+using namespace llvm;
+
+// Register the AliasAnalysis interface, providing a nice name to refer to.
+static RegisterAnalysisGroup<AliasAnalysis> Z("Alias Analysis");
+char AliasAnalysis::ID = 0;
+
+//===----------------------------------------------------------------------===//
+// Default chaining methods
+//===----------------------------------------------------------------------===//
+
+AliasAnalysis::AliasResult
+AliasAnalysis::alias(const Value *V1, unsigned V1Size,
+                     const Value *V2, unsigned V2Size) {
+  assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+  return AA->alias(V1, V1Size, V2, V2Size);
+}
+
+bool AliasAnalysis::pointsToConstantMemory(const Value *P) {
+  assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+  return AA->pointsToConstantMemory(P);
+}
+
+void AliasAnalysis::deleteValue(Value *V) {
+  assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+  AA->deleteValue(V);
+}
+
+void AliasAnalysis::copyValue(Value *From, Value *To) {
+  assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+  AA->copyValue(From, To);
+}
+
+AliasAnalysis::ModRefResult
+AliasAnalysis::getModRefInfo(CallSite CS1, CallSite CS2) {
+  // FIXME: we can do better.
+  assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+  return AA->getModRefInfo(CS1, CS2);
+}
+
+
+//===----------------------------------------------------------------------===//
+// AliasAnalysis non-virtual helper method implementation
+//===----------------------------------------------------------------------===//
+
+AliasAnalysis::ModRefResult
+AliasAnalysis::getModRefInfo(LoadInst *L, Value *P, unsigned Size) {
+  return alias(L->getOperand(0), getTypeStoreSize(L->getType()),
+               P, Size) ? Ref : NoModRef;
+}
+
+AliasAnalysis::ModRefResult
+AliasAnalysis::getModRefInfo(StoreInst *S, Value *P, unsigned Size) {
+  // If the stored address cannot alias the pointer in question, then the
+  // pointer cannot be modified by the store.
+  if (!alias(S->getOperand(1),
+             getTypeStoreSize(S->getOperand(0)->getType()), P, Size))
+    return NoModRef;
+
+  // If the pointer is a pointer to constant memory, then it could not have been
+  // modified by this store.
+  return pointsToConstantMemory(P) ? NoModRef : Mod;
+}
+
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(CallSite CS,
+                                 std::vector<PointerAccessInfo> *Info) {
+  if (CS.doesNotAccessMemory())
+    // Can't do better than this.
+    return DoesNotAccessMemory;
+  ModRefBehavior MRB = getModRefBehavior(CS.getCalledFunction(), Info);
+  if (MRB != DoesNotAccessMemory && CS.onlyReadsMemory())
+    return OnlyReadsMemory;
+  return MRB;
+}
+
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(Function *F,
+                                 std::vector<PointerAccessInfo> *Info) {
+  if (F) {
+    if (F->doesNotAccessMemory())
+      // Can't do better than this.
+      return DoesNotAccessMemory;
+    if (F->onlyReadsMemory())
+      return OnlyReadsMemory;
+    if (unsigned id = F->getIntrinsicID())
+      return getModRefBehavior(id);
+  }
+  return UnknownModRefBehavior;
+}
+
+AliasAnalysis::ModRefBehavior AliasAnalysis::getModRefBehavior(unsigned iid) {
+#define GET_INTRINSIC_MODREF_BEHAVIOR
+#include "llvm/Intrinsics.gen"
+#undef GET_INTRINSIC_MODREF_BEHAVIOR
+}
+
+AliasAnalysis::ModRefResult
+AliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
+  ModRefBehavior MRB = getModRefBehavior(CS);
+  if (MRB == DoesNotAccessMemory)
+    return NoModRef;
+  
+  ModRefResult Mask = ModRef;
+  if (MRB == OnlyReadsMemory)
+    Mask = Ref;
+  else if (MRB == AliasAnalysis::AccessesArguments) {
+    bool doesAlias = false;
+    for (CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
+         AI != AE; ++AI)
+      if (!isNoAlias(*AI, ~0U, P, Size)) {
+        doesAlias = true;
+        break;
+      }
+
+    if (!doesAlias)
+      return NoModRef;
+  }
+
+  if (!AA) return Mask;
+
+  // If P points to a constant memory location, the call definitely could not
+  // modify the memory location.
+  if ((Mask & Mod) && AA->pointsToConstantMemory(P))
+    Mask = ModRefResult(Mask & ~Mod);
+
+  return ModRefResult(Mask & AA->getModRefInfo(CS, P, Size));
+}
+
+// AliasAnalysis destructor: DO NOT move this to the header file for
+// AliasAnalysis or else clients of the AliasAnalysis class may not depend on
+// the AliasAnalysis.o file in the current .a file, causing alias analysis
+// support to not be included in the tool correctly!
+//
+AliasAnalysis::~AliasAnalysis() {}
+
+/// InitializeAliasAnalysis - Subclasses must call this method to initialize the
+/// AliasAnalysis interface before any other methods are called.
+///
+void AliasAnalysis::InitializeAliasAnalysis(Pass *P) {
+  TD = P->getAnalysisIfAvailable<TargetData>();
+  AA = &P->getAnalysis<AliasAnalysis>();
+}
+
+// getAnalysisUsage - All alias analysis implementations should invoke this
+// directly (using AliasAnalysis::getAnalysisUsage(AU)).
+void AliasAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<AliasAnalysis>();         // All AA's chain
+}
+
+/// getTypeStoreSize - Return the TargetData store size for the given type,
+/// if known, or a conservative value otherwise.
+///
+unsigned AliasAnalysis::getTypeStoreSize(const Type *Ty) {
+  return TD ? TD->getTypeStoreSize(Ty) : ~0u;
+}
+
+/// canBasicBlockModify - Return true if it is possible for execution of the
+/// specified basic block to modify the value pointed to by Ptr.
+///
+bool AliasAnalysis::canBasicBlockModify(const BasicBlock &BB,
+                                        const Value *Ptr, unsigned Size) {
+  return canInstructionRangeModify(BB.front(), BB.back(), Ptr, Size);
+}
+
+/// canInstructionRangeModify - Return true if it is possible for the execution
+/// of the specified instructions to modify the value pointed to by Ptr.  The
+/// instructions to consider are all of the instructions in the range of [I1,I2]
+/// INCLUSIVE.  I1 and I2 must be in the same basic block.
+///
+bool AliasAnalysis::canInstructionRangeModify(const Instruction &I1,
+                                              const Instruction &I2,
+                                              const Value *Ptr, unsigned Size) {
+  assert(I1.getParent() == I2.getParent() &&
+         "Instructions not in same basic block!");
+  BasicBlock::iterator I = const_cast<Instruction*>(&I1);
+  BasicBlock::iterator E = const_cast<Instruction*>(&I2);
+  ++E;  // Convert from inclusive to exclusive range.
+
+  for (; I != E; ++I) // Check every instruction in range
+    if (getModRefInfo(I, const_cast<Value*>(Ptr), Size) & Mod)
+      return true;
+  return false;
+}
+
+/// isNoAliasCall - Return true if this pointer is returned by a noalias
+/// function.
+bool llvm::isNoAliasCall(const Value *V) {
+  if (isa<CallInst>(V) || isa<InvokeInst>(V))
+    return CallSite(const_cast<Instruction*>(cast<Instruction>(V)))
+      .paramHasAttr(0, Attribute::NoAlias);
+  return false;
+}
+
+/// isIdentifiedObject - Return true if this pointer refers to a distinct and
+/// identifiable object.  This returns true for:
+///    Global Variables and Functions (but not Global Aliases)
+///    Allocas and Mallocs
+///    ByVal and NoAlias Arguments
+///    NoAlias returns
+///
+bool llvm::isIdentifiedObject(const Value *V) {
+  if (isa<AllocaInst>(V) || isNoAliasCall(V))
+    return true;
+  if (isa<GlobalValue>(V) && !isa<GlobalAlias>(V))
+    return true;
+  if (const Argument *A = dyn_cast<Argument>(V))
+    return A->hasNoAliasAttr() || A->hasByValAttr();
+  return false;
+}
+
+// Because of the way .a files work, we must force the BasicAA implementation to
+// be pulled in if the AliasAnalysis classes are pulled in.  Otherwise we run
+// the risk of AliasAnalysis being used, but the default implementation not
+// being linked into the tool that uses it.
+DEFINING_FILE_FOR(AliasAnalysis)