// A a;
// } B;
//
-// For an acess to B.a.s, we attach !5 (a path tag node) to the load/store
+// For an access to B.a.s, we attach !5 (a path tag node) to the load/store
// instruction. The base type is !4 (struct B), the access type is !2 (scalar
// type short) and the offset is 4.
//
//
//===----------------------------------------------------------------------===//
-#include "llvm/Analysis/Passes.h"
-#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/TypeBasedAliasAnalysis.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/ADT/SetVector.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
-#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
static cl::opt<bool> EnableTBAA("enable-tbaa", cl::init(true));
namespace {
- /// TBAANode - This is a simple wrapper around an MDNode which provides a
- /// higher-level interface by hiding the details of how alias analysis
- /// information is encoded in its operands.
- class TBAANode {
- const MDNode *Node;
-
- public:
- TBAANode() : Node(0) {}
- explicit TBAANode(const MDNode *N) : Node(N) {}
-
- /// getNode - Get the MDNode for this TBAANode.
- const MDNode *getNode() const { return Node; }
-
- /// getParent - Get this TBAANode's Alias tree parent.
- TBAANode getParent() const {
- if (Node->getNumOperands() < 2)
- return TBAANode();
- MDNode *P = dyn_cast_or_null<MDNode>(Node->getOperand(1));
- if (!P)
- return TBAANode();
- // Ok, this node has a valid parent. Return it.
- return TBAANode(P);
- }
+/// TBAANode - This is a simple wrapper around an MDNode which provides a
+/// higher-level interface by hiding the details of how alias analysis
+/// information is encoded in its operands.
+class TBAANode {
+ const MDNode *Node;
+
+public:
+ TBAANode() : Node(nullptr) {}
+ explicit TBAANode(const MDNode *N) : Node(N) {}
+
+ /// getNode - Get the MDNode for this TBAANode.
+ const MDNode *getNode() const { return Node; }
+
+ /// getParent - Get this TBAANode's Alias tree parent.
+ TBAANode getParent() const {
+ if (Node->getNumOperands() < 2)
+ return TBAANode();
+ MDNode *P = dyn_cast_or_null<MDNode>(Node->getOperand(1));
+ if (!P)
+ return TBAANode();
+ // Ok, this node has a valid parent. Return it.
+ return TBAANode(P);
+ }
- /// TypeIsImmutable - Test if this TBAANode represents a type for objects
- /// which are not modified (by any means) in the context where this
- /// AliasAnalysis is relevant.
- bool TypeIsImmutable() const {
- if (Node->getNumOperands() < 3)
- return false;
- ConstantInt *CI = dyn_cast<ConstantInt>(Node->getOperand(2));
- if (!CI)
- return false;
- return CI->getValue()[0];
- }
- };
+ /// TypeIsImmutable - Test if this TBAANode represents a type for objects
+ /// which are not modified (by any means) in the context where this
+ /// AliasAnalysis is relevant.
+ bool TypeIsImmutable() const {
+ if (Node->getNumOperands() < 3)
+ return false;
+ ConstantInt *CI = mdconst::dyn_extract<ConstantInt>(Node->getOperand(2));
+ if (!CI)
+ return false;
+ return CI->getValue()[0];
+ }
+};
- /// This is a simple wrapper around an MDNode which provides a
- /// higher-level interface by hiding the details of how alias analysis
- /// information is encoded in its operands.
- class TBAAStructTagNode {
- /// This node should be created with createTBAAStructTagNode.
- const MDNode *Node;
+/// This is a simple wrapper around an MDNode which provides a
+/// higher-level interface by hiding the details of how alias analysis
+/// information is encoded in its operands.
+class TBAAStructTagNode {
+ /// This node should be created with createTBAAStructTagNode.
+ const MDNode *Node;
- public:
- TBAAStructTagNode() : Node(0) {}
- explicit TBAAStructTagNode(const MDNode *N) : Node(N) {}
+public:
+ explicit TBAAStructTagNode(const MDNode *N) : Node(N) {}
- /// Get the MDNode for this TBAAStructTagNode.
- const MDNode *getNode() const { return Node; }
+ /// Get the MDNode for this TBAAStructTagNode.
+ const MDNode *getNode() const { return Node; }
- const MDNode *getBaseType() const {
- return dyn_cast_or_null<MDNode>(Node->getOperand(0));
- }
- const MDNode *getAccessType() const {
- return dyn_cast_or_null<MDNode>(Node->getOperand(1));
- }
- uint64_t getOffset() const {
- return cast<ConstantInt>(Node->getOperand(2))->getZExtValue();
- }
- /// TypeIsImmutable - Test if this TBAAStructTagNode represents a type for
- /// objects which are not modified (by any means) in the context where this
- /// AliasAnalysis is relevant.
- bool TypeIsImmutable() const {
- if (Node->getNumOperands() < 4)
- return false;
- ConstantInt *CI = dyn_cast<ConstantInt>(Node->getOperand(3));
- if (!CI)
- return false;
- return CI->getValue()[0];
- }
- };
-
- /// This is a simple wrapper around an MDNode which provides a
- /// higher-level interface by hiding the details of how alias analysis
- /// information is encoded in its operands.
- class TBAAStructTypeNode {
- /// This node should be created with createTBAAStructTypeNode.
- const MDNode *Node;
-
- public:
- TBAAStructTypeNode() : Node(0) {}
- explicit TBAAStructTypeNode(const MDNode *N) : Node(N) {}
-
- /// Get the MDNode for this TBAAStructTypeNode.
- const MDNode *getNode() const { return Node; }
-
- /// Get this TBAAStructTypeNode's field in the type DAG with
- /// given offset. Update the offset to be relative to the field type.
- TBAAStructTypeNode getParent(uint64_t &Offset) const {
- // Parent can be omitted for the root node.
- if (Node->getNumOperands() < 2)
- return TBAAStructTypeNode();
-
- // Fast path for a scalar type node and a struct type node with a single
- // field.
- if (Node->getNumOperands() <= 3) {
- uint64_t Cur = Node->getNumOperands() == 2 ? 0 :
- cast<ConstantInt>(Node->getOperand(2))->getZExtValue();
- Offset -= Cur;
- MDNode *P = dyn_cast_or_null<MDNode>(Node->getOperand(1));
- if (!P)
- return TBAAStructTypeNode();
- return TBAAStructTypeNode(P);
- }
-
- // Assume the offsets are in order. We return the previous field if
- // the current offset is bigger than the given offset.
- unsigned TheIdx = 0;
- for (unsigned Idx = 1; Idx < Node->getNumOperands(); Idx += 2) {
- uint64_t Cur = cast<ConstantInt>(Node->getOperand(Idx + 1))->
- getZExtValue();
- if (Cur > Offset) {
- assert(Idx >= 3 &&
- "TBAAStructTypeNode::getParent should have an offset match!");
- TheIdx = Idx - 2;
- break;
- }
- }
- // Move along the last field.
- if (TheIdx == 0)
- TheIdx = Node->getNumOperands() - 2;
- uint64_t Cur = cast<ConstantInt>(Node->getOperand(TheIdx + 1))->
- getZExtValue();
+ const MDNode *getBaseType() const {
+ return dyn_cast_or_null<MDNode>(Node->getOperand(0));
+ }
+ const MDNode *getAccessType() const {
+ return dyn_cast_or_null<MDNode>(Node->getOperand(1));
+ }
+ uint64_t getOffset() const {
+ return mdconst::extract<ConstantInt>(Node->getOperand(2))->getZExtValue();
+ }
+ /// TypeIsImmutable - Test if this TBAAStructTagNode represents a type for
+ /// objects which are not modified (by any means) in the context where this
+ /// AliasAnalysis is relevant.
+ bool TypeIsImmutable() const {
+ if (Node->getNumOperands() < 4)
+ return false;
+ ConstantInt *CI = mdconst::dyn_extract<ConstantInt>(Node->getOperand(3));
+ if (!CI)
+ return false;
+ return CI->getValue()[0];
+ }
+};
+
+/// This is a simple wrapper around an MDNode which provides a
+/// higher-level interface by hiding the details of how alias analysis
+/// information is encoded in its operands.
+class TBAAStructTypeNode {
+ /// This node should be created with createTBAAStructTypeNode.
+ const MDNode *Node;
+
+public:
+ TBAAStructTypeNode() : Node(nullptr) {}
+ explicit TBAAStructTypeNode(const MDNode *N) : Node(N) {}
+
+ /// Get the MDNode for this TBAAStructTypeNode.
+ const MDNode *getNode() const { return Node; }
+
+ /// Get this TBAAStructTypeNode's field in the type DAG with
+ /// given offset. Update the offset to be relative to the field type.
+ TBAAStructTypeNode getParent(uint64_t &Offset) const {
+ // Parent can be omitted for the root node.
+ if (Node->getNumOperands() < 2)
+ return TBAAStructTypeNode();
+
+ // Fast path for a scalar type node and a struct type node with a single
+ // field.
+ if (Node->getNumOperands() <= 3) {
+ uint64_t Cur = Node->getNumOperands() == 2
+ ? 0
+ : mdconst::extract<ConstantInt>(Node->getOperand(2))
+ ->getZExtValue();
Offset -= Cur;
- MDNode *P = dyn_cast_or_null<MDNode>(Node->getOperand(TheIdx));
+ MDNode *P = dyn_cast_or_null<MDNode>(Node->getOperand(1));
if (!P)
return TBAAStructTypeNode();
return TBAAStructTypeNode(P);
}
- };
-}
-namespace {
- /// TypeBasedAliasAnalysis - This is a simple alias analysis
- /// implementation that uses TypeBased to answer queries.
- class TypeBasedAliasAnalysis : public ImmutablePass,
- public AliasAnalysis {
- public:
- static char ID; // Class identification, replacement for typeinfo
- TypeBasedAliasAnalysis() : ImmutablePass(ID) {
- initializeTypeBasedAliasAnalysisPass(*PassRegistry::getPassRegistry());
- }
-
- virtual void initializePass() {
- InitializeAliasAnalysis(this);
- }
-
- /// getAdjustedAnalysisPointer - This method is used when a pass implements
- /// an analysis interface through multiple inheritance. If needed, it
- /// should override this to adjust the this pointer as needed for the
- /// specified pass info.
- virtual void *getAdjustedAnalysisPointer(const void *PI) {
- if (PI == &AliasAnalysis::ID)
- return (AliasAnalysis*)this;
- return this;
+ // Assume the offsets are in order. We return the previous field if
+ // the current offset is bigger than the given offset.
+ unsigned TheIdx = 0;
+ for (unsigned Idx = 1; Idx < Node->getNumOperands(); Idx += 2) {
+ uint64_t Cur = mdconst::extract<ConstantInt>(Node->getOperand(Idx + 1))
+ ->getZExtValue();
+ if (Cur > Offset) {
+ assert(Idx >= 3 &&
+ "TBAAStructTypeNode::getParent should have an offset match!");
+ TheIdx = Idx - 2;
+ break;
+ }
}
-
- bool Aliases(const MDNode *A, const MDNode *B) const;
- bool PathAliases(const MDNode *A, const MDNode *B) const;
-
- private:
- virtual void getAnalysisUsage(AnalysisUsage &AU) const;
- virtual AliasResult alias(const Location &LocA, const Location &LocB);
- virtual bool pointsToConstantMemory(const Location &Loc, bool OrLocal);
- virtual ModRefBehavior getModRefBehavior(ImmutableCallSite CS);
- virtual ModRefBehavior getModRefBehavior(const Function *F);
- virtual ModRefResult getModRefInfo(ImmutableCallSite CS,
- const Location &Loc);
- virtual ModRefResult getModRefInfo(ImmutableCallSite CS1,
- ImmutableCallSite CS2);
- };
-} // End of anonymous namespace
-
-// Register this pass...
-char TypeBasedAliasAnalysis::ID = 0;
-INITIALIZE_AG_PASS(TypeBasedAliasAnalysis, AliasAnalysis, "tbaa",
- "Type-Based Alias Analysis", false, true, false)
-
-ImmutablePass *llvm::createTypeBasedAliasAnalysisPass() {
- return new TypeBasedAliasAnalysis();
-}
-
-void
-TypeBasedAliasAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesAll();
- AliasAnalysis::getAnalysisUsage(AU);
+ // Move along the last field.
+ if (TheIdx == 0)
+ TheIdx = Node->getNumOperands() - 2;
+ uint64_t Cur = mdconst::extract<ConstantInt>(Node->getOperand(TheIdx + 1))
+ ->getZExtValue();
+ Offset -= Cur;
+ MDNode *P = dyn_cast_or_null<MDNode>(Node->getOperand(TheIdx));
+ if (!P)
+ return TBAAStructTypeNode();
+ return TBAAStructTypeNode(P);
+ }
+};
}
/// Check the first operand of the tbaa tag node, if it is a MDNode, we treat
return isa<MDNode>(MD->getOperand(0)) && MD->getNumOperands() >= 3;
}
+AliasResult TypeBasedAAResult::alias(const MemoryLocation &LocA,
+ const MemoryLocation &LocB) {
+ if (!EnableTBAA)
+ return AAResultBase::alias(LocA, LocB);
+
+ // Get the attached MDNodes. If either value lacks a tbaa MDNode, we must
+ // be conservative.
+ const MDNode *AM = LocA.AATags.TBAA;
+ if (!AM)
+ return AAResultBase::alias(LocA, LocB);
+ const MDNode *BM = LocB.AATags.TBAA;
+ if (!BM)
+ return AAResultBase::alias(LocA, LocB);
+
+ // If they may alias, chain to the next AliasAnalysis.
+ if (Aliases(AM, BM))
+ return AAResultBase::alias(LocA, LocB);
+
+ // Otherwise return a definitive result.
+ return NoAlias;
+}
+
+bool TypeBasedAAResult::pointsToConstantMemory(const MemoryLocation &Loc,
+ bool OrLocal) {
+ if (!EnableTBAA)
+ return AAResultBase::pointsToConstantMemory(Loc, OrLocal);
+
+ const MDNode *M = Loc.AATags.TBAA;
+ if (!M)
+ return AAResultBase::pointsToConstantMemory(Loc, OrLocal);
+
+ // If this is an "immutable" type, we can assume the pointer is pointing
+ // to constant memory.
+ if ((!isStructPathTBAA(M) && TBAANode(M).TypeIsImmutable()) ||
+ (isStructPathTBAA(M) && TBAAStructTagNode(M).TypeIsImmutable()))
+ return true;
+
+ return AAResultBase::pointsToConstantMemory(Loc, OrLocal);
+}
+
+FunctionModRefBehavior
+TypeBasedAAResult::getModRefBehavior(ImmutableCallSite CS) {
+ if (!EnableTBAA)
+ return AAResultBase::getModRefBehavior(CS);
+
+ FunctionModRefBehavior Min = FMRB_UnknownModRefBehavior;
+
+ // If this is an "immutable" type, we can assume the call doesn't write
+ // to memory.
+ if (const MDNode *M = CS.getInstruction()->getMetadata(LLVMContext::MD_tbaa))
+ if ((!isStructPathTBAA(M) && TBAANode(M).TypeIsImmutable()) ||
+ (isStructPathTBAA(M) && TBAAStructTagNode(M).TypeIsImmutable()))
+ Min = FMRB_OnlyReadsMemory;
+
+ return FunctionModRefBehavior(AAResultBase::getModRefBehavior(CS) & Min);
+}
+
+FunctionModRefBehavior TypeBasedAAResult::getModRefBehavior(const Function *F) {
+ // Functions don't have metadata. Just chain to the next implementation.
+ return AAResultBase::getModRefBehavior(F);
+}
+
+ModRefInfo TypeBasedAAResult::getModRefInfo(ImmutableCallSite CS,
+ const MemoryLocation &Loc) {
+ if (!EnableTBAA)
+ return AAResultBase::getModRefInfo(CS, Loc);
+
+ if (const MDNode *L = Loc.AATags.TBAA)
+ if (const MDNode *M =
+ CS.getInstruction()->getMetadata(LLVMContext::MD_tbaa))
+ if (!Aliases(L, M))
+ return MRI_NoModRef;
+
+ return AAResultBase::getModRefInfo(CS, Loc);
+}
+
+ModRefInfo TypeBasedAAResult::getModRefInfo(ImmutableCallSite CS1,
+ ImmutableCallSite CS2) {
+ if (!EnableTBAA)
+ return AAResultBase::getModRefInfo(CS1, CS2);
+
+ if (const MDNode *M1 =
+ CS1.getInstruction()->getMetadata(LLVMContext::MD_tbaa))
+ if (const MDNode *M2 =
+ CS2.getInstruction()->getMetadata(LLVMContext::MD_tbaa))
+ if (!Aliases(M1, M2))
+ return MRI_NoModRef;
+
+ return AAResultBase::getModRefInfo(CS1, CS2);
+}
+
+bool MDNode::isTBAAVtableAccess() const {
+ if (!isStructPathTBAA(this)) {
+ if (getNumOperands() < 1)
+ return false;
+ if (MDString *Tag1 = dyn_cast<MDString>(getOperand(0))) {
+ if (Tag1->getString() == "vtable pointer")
+ return true;
+ }
+ return false;
+ }
+
+ // For struct-path aware TBAA, we use the access type of the tag.
+ if (getNumOperands() < 2)
+ return false;
+ MDNode *Tag = cast_or_null<MDNode>(getOperand(1));
+ if (!Tag)
+ return false;
+ if (MDString *Tag1 = dyn_cast<MDString>(Tag->getOperand(0))) {
+ if (Tag1->getString() == "vtable pointer")
+ return true;
+ }
+ return false;
+}
+
+MDNode *MDNode::getMostGenericTBAA(MDNode *A, MDNode *B) {
+ if (!A || !B)
+ return nullptr;
+
+ if (A == B)
+ return A;
+
+ // For struct-path aware TBAA, we use the access type of the tag.
+ bool StructPath = isStructPathTBAA(A) && isStructPathTBAA(B);
+ if (StructPath) {
+ A = cast_or_null<MDNode>(A->getOperand(1));
+ if (!A)
+ return nullptr;
+ B = cast_or_null<MDNode>(B->getOperand(1));
+ if (!B)
+ return nullptr;
+ }
+
+ SmallSetVector<MDNode *, 4> PathA;
+ MDNode *T = A;
+ while (T) {
+ if (PathA.count(T))
+ report_fatal_error("Cycle found in TBAA metadata.");
+ PathA.insert(T);
+ T = T->getNumOperands() >= 2 ? cast_or_null<MDNode>(T->getOperand(1))
+ : nullptr;
+ }
+
+ SmallSetVector<MDNode *, 4> PathB;
+ T = B;
+ while (T) {
+ if (PathB.count(T))
+ report_fatal_error("Cycle found in TBAA metadata.");
+ PathB.insert(T);
+ T = T->getNumOperands() >= 2 ? cast_or_null<MDNode>(T->getOperand(1))
+ : nullptr;
+ }
+
+ int IA = PathA.size() - 1;
+ int IB = PathB.size() - 1;
+
+ MDNode *Ret = nullptr;
+ while (IA >= 0 && IB >= 0) {
+ if (PathA[IA] == PathB[IB])
+ Ret = PathA[IA];
+ else
+ break;
+ --IA;
+ --IB;
+ }
+ if (!StructPath)
+ return Ret;
+
+ if (!Ret)
+ return nullptr;
+ // We need to convert from a type node to a tag node.
+ Type *Int64 = IntegerType::get(A->getContext(), 64);
+ Metadata *Ops[3] = {Ret, Ret,
+ ConstantAsMetadata::get(ConstantInt::get(Int64, 0))};
+ return MDNode::get(A->getContext(), Ops);
+}
+
+void Instruction::getAAMetadata(AAMDNodes &N, bool Merge) const {
+ if (Merge)
+ N.TBAA =
+ MDNode::getMostGenericTBAA(N.TBAA, getMetadata(LLVMContext::MD_tbaa));
+ else
+ N.TBAA = getMetadata(LLVMContext::MD_tbaa);
+
+ if (Merge)
+ N.Scope = MDNode::getMostGenericAliasScope(
+ N.Scope, getMetadata(LLVMContext::MD_alias_scope));
+ else
+ N.Scope = getMetadata(LLVMContext::MD_alias_scope);
+
+ if (Merge)
+ N.NoAlias =
+ MDNode::intersect(N.NoAlias, getMetadata(LLVMContext::MD_noalias));
+ else
+ N.NoAlias = getMetadata(LLVMContext::MD_noalias);
+}
+
/// Aliases - Test whether the type represented by A may alias the
/// type represented by B.
-bool
-TypeBasedAliasAnalysis::Aliases(const MDNode *A,
- const MDNode *B) const {
- if (isStructPathTBAA(A))
+bool TypeBasedAAResult::Aliases(const MDNode *A, const MDNode *B) const {
+ // Make sure that both MDNodes are struct-path aware.
+ if (isStructPathTBAA(A) && isStructPathTBAA(B))
return PathAliases(A, B);
// Keep track of the root node for A and B.
TBAANode RootA, RootB;
// Climb the tree from A to see if we reach B.
- for (TBAANode T(A); ; ) {
+ for (TBAANode T(A);;) {
if (T.getNode() == B)
// B is an ancestor of A.
return true;
}
// Climb the tree from B to see if we reach A.
- for (TBAANode T(B); ; ) {
+ for (TBAANode T(B);;) {
if (T.getNode() == A)
// A is an ancestor of B.
return true;
}
// Neither node is an ancestor of the other.
-
+
// If they have different roots, they're part of different potentially
// unrelated type systems, so we must be conservative.
if (RootA.getNode() != RootB.getNode())
/// Test whether the struct-path tag represented by A may alias the
/// struct-path tag represented by B.
-bool
-TypeBasedAliasAnalysis::PathAliases(const MDNode *A,
- const MDNode *B) const {
+bool TypeBasedAAResult::PathAliases(const MDNode *A, const MDNode *B) const {
+ // Verify that both input nodes are struct-path aware.
+ assert(isStructPathTBAA(A) && "MDNode A is not struct-path aware.");
+ assert(isStructPathTBAA(B) && "MDNode B is not struct-path aware.");
+
// Keep track of the root node for A and B.
TBAAStructTypeNode RootA, RootB;
TBAAStructTagNode TagA(A), TagB(B);
const MDNode *BaseA = TagA.getBaseType();
const MDNode *BaseB = TagB.getBaseType();
uint64_t OffsetA = TagA.getOffset(), OffsetB = TagB.getOffset();
- for (TBAAStructTypeNode T(BaseA); ; ) {
+ for (TBAAStructTypeNode T(BaseA);;) {
if (T.getNode() == BaseB)
// Base type of A encloses base type of B, check if the offsets match.
return OffsetA == OffsetB;
// Reset OffsetA and climb the type DAG from base type of B to see if we reach
// base type of A.
OffsetA = TagA.getOffset();
- for (TBAAStructTypeNode T(BaseB); ; ) {
+ for (TBAAStructTypeNode T(BaseB);;) {
if (T.getNode() == BaseA)
// Base type of B encloses base type of A, check if the offsets match.
return OffsetA == OffsetB;
return false;
}
-AliasAnalysis::AliasResult
-TypeBasedAliasAnalysis::alias(const Location &LocA,
- const Location &LocB) {
- if (!EnableTBAA)
- return AliasAnalysis::alias(LocA, LocB);
-
- // Get the attached MDNodes. If either value lacks a tbaa MDNode, we must
- // be conservative.
- const MDNode *AM = LocA.TBAATag;
- if (!AM) return AliasAnalysis::alias(LocA, LocB);
- const MDNode *BM = LocB.TBAATag;
- if (!BM) return AliasAnalysis::alias(LocA, LocB);
-
- // If they may alias, chain to the next AliasAnalysis.
- if (Aliases(AM, BM))
- return AliasAnalysis::alias(LocA, LocB);
-
- // Otherwise return a definitive result.
- return NoAlias;
+TypeBasedAAResult TypeBasedAA::run(Function &F, AnalysisManager<Function> *AM) {
+ return TypeBasedAAResult(AM->getResult<TargetLibraryAnalysis>(F));
}
-bool TypeBasedAliasAnalysis::pointsToConstantMemory(const Location &Loc,
- bool OrLocal) {
- if (!EnableTBAA)
- return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal);
+char TypeBasedAA::PassID;
- const MDNode *M = Loc.TBAATag;
- if (!M) return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal);
+char TypeBasedAAWrapperPass::ID = 0;
+INITIALIZE_PASS_BEGIN(TypeBasedAAWrapperPass, "tbaa",
+ "Type-Based Alias Analysis", false, true)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
+INITIALIZE_PASS_END(TypeBasedAAWrapperPass, "tbaa", "Type-Based Alias Analysis",
+ false, true)
- // If this is an "immutable" type, we can assume the pointer is pointing
- // to constant memory.
- if ((!isStructPathTBAA(M) && TBAANode(M).TypeIsImmutable()) ||
- (isStructPathTBAA(M) && TBAAStructTagNode(M).TypeIsImmutable()))
- return true;
-
- return AliasAnalysis::pointsToConstantMemory(Loc, OrLocal);
+ImmutablePass *llvm::createTypeBasedAAWrapperPass() {
+ return new TypeBasedAAWrapperPass();
}
-AliasAnalysis::ModRefBehavior
-TypeBasedAliasAnalysis::getModRefBehavior(ImmutableCallSite CS) {
- if (!EnableTBAA)
- return AliasAnalysis::getModRefBehavior(CS);
-
- ModRefBehavior Min = UnknownModRefBehavior;
-
- // If this is an "immutable" type, we can assume the call doesn't write
- // to memory.
- if (const MDNode *M = CS.getInstruction()->getMetadata(LLVMContext::MD_tbaa))
- if ((!isStructPathTBAA(M) && TBAANode(M).TypeIsImmutable()) ||
- (isStructPathTBAA(M) && TBAAStructTagNode(M).TypeIsImmutable()))
- Min = OnlyReadsMemory;
-
- return ModRefBehavior(AliasAnalysis::getModRefBehavior(CS) & Min);
-}
-
-AliasAnalysis::ModRefBehavior
-TypeBasedAliasAnalysis::getModRefBehavior(const Function *F) {
- // Functions don't have metadata. Just chain to the next implementation.
- return AliasAnalysis::getModRefBehavior(F);
-}
-
-AliasAnalysis::ModRefResult
-TypeBasedAliasAnalysis::getModRefInfo(ImmutableCallSite CS,
- const Location &Loc) {
- if (!EnableTBAA)
- return AliasAnalysis::getModRefInfo(CS, Loc);
-
- if (const MDNode *L = Loc.TBAATag)
- if (const MDNode *M =
- CS.getInstruction()->getMetadata(LLVMContext::MD_tbaa))
- if (!Aliases(L, M))
- return NoModRef;
-
- return AliasAnalysis::getModRefInfo(CS, Loc);
+TypeBasedAAWrapperPass::TypeBasedAAWrapperPass() : ImmutablePass(ID) {
+ initializeTypeBasedAAWrapperPassPass(*PassRegistry::getPassRegistry());
}
-AliasAnalysis::ModRefResult
-TypeBasedAliasAnalysis::getModRefInfo(ImmutableCallSite CS1,
- ImmutableCallSite CS2) {
- if (!EnableTBAA)
- return AliasAnalysis::getModRefInfo(CS1, CS2);
-
- if (const MDNode *M1 =
- CS1.getInstruction()->getMetadata(LLVMContext::MD_tbaa))
- if (const MDNode *M2 =
- CS2.getInstruction()->getMetadata(LLVMContext::MD_tbaa))
- if (!Aliases(M1, M2))
- return NoModRef;
-
- return AliasAnalysis::getModRefInfo(CS1, CS2);
+bool TypeBasedAAWrapperPass::doInitialization(Module &M) {
+ Result.reset(new TypeBasedAAResult(
+ getAnalysis<TargetLibraryInfoWrapperPass>().getTLI()));
+ return false;
}
-bool MDNode::isTBAAVtableAccess() const {
- if (!isStructPathTBAA(this)) {
- if (getNumOperands() < 1) return false;
- if (MDString *Tag1 = dyn_cast<MDString>(getOperand(0))) {
- if (Tag1->getString() == "vtable pointer") return true;
- }
- return false;
- }
-
- // For struct-path aware TBAA, we use the access type of the tag.
- if (getNumOperands() < 2) return false;
- MDNode *Tag = cast_or_null<MDNode>(getOperand(1));
- if (!Tag) return false;
- if (MDString *Tag1 = dyn_cast<MDString>(Tag->getOperand(0))) {
- if (Tag1->getString() == "vtable pointer") return true;
- }
- return false;
+bool TypeBasedAAWrapperPass::doFinalization(Module &M) {
+ Result.reset();
+ return false;
}
-MDNode *MDNode::getMostGenericTBAA(MDNode *A, MDNode *B) {
- if (!A || !B)
- return NULL;
-
- if (A == B)
- return A;
-
- // For struct-path aware TBAA, we use the access type of the tag.
- bool StructPath = isStructPathTBAA(A);
- if (StructPath) {
- A = cast_or_null<MDNode>(A->getOperand(1));
- if (!A) return 0;
- B = cast_or_null<MDNode>(B->getOperand(1));
- if (!B) return 0;
- }
-
- SmallVector<MDNode *, 4> PathA;
- MDNode *T = A;
- while (T) {
- PathA.push_back(T);
- T = T->getNumOperands() >= 2 ? cast_or_null<MDNode>(T->getOperand(1)) : 0;
- }
-
- SmallVector<MDNode *, 4> PathB;
- T = B;
- while (T) {
- PathB.push_back(T);
- T = T->getNumOperands() >= 2 ? cast_or_null<MDNode>(T->getOperand(1)) : 0;
- }
-
- int IA = PathA.size() - 1;
- int IB = PathB.size() - 1;
-
- MDNode *Ret = 0;
- while (IA >= 0 && IB >=0) {
- if (PathA[IA] == PathB[IB])
- Ret = PathA[IA];
- else
- break;
- --IA;
- --IB;
- }
- if (!StructPath)
- return Ret;
-
- if (!Ret)
- return 0;
- // We need to convert from a type node to a tag node.
- Type *Int64 = IntegerType::get(A->getContext(), 64);
- Value *Ops[3] = { Ret, Ret, ConstantInt::get(Int64, 0) };
- return MDNode::get(A->getContext(), Ops);
+void TypeBasedAAWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesAll();
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
}
projects / oota-llvm.git / blobdiff