// which automatically provides functionality for the entire suite of client
// APIs.
//
-// This API represents memory as a (Pointer, Size) pair. The Pointer component
-// specifies the base memory address of the region, the Size specifies how large
-// of an area is being queried, or UnknownSize if the size is not known.
-// Pointers that point to two completely different objects in memory never
-// alias, regardless of the value of the Size component.
+// This API identifies memory regions with the MemoryLocation class. The pointer
+// component specifies the base memory address of the region. The Size specifies
+// the maximum size (in address units) of the memory region, or
+// MemoryLocation::UnknownSize if the size is not known. The TBAA tag
+// identifies the "type" of the memory reference; see the
+// TypeBasedAliasAnalysis class for details.
+//
+// Some non-obvious details include:
+// - Pointers that point to two completely different objects in memory never
+// alias, regardless of the value of the Size component.
+// - NoAlias doesn't imply inequal pointers. The most obvious example of this
+// is two pointers to constant memory. Even if they are equal, constant
+// memory is never stored to, so there will never be any dependencies.
+// In this and other situations, the pointers may be both NoAlias and
+// MustAlias at the same time. The current API can only return one result,
+// though this is rarely a problem in practice.
//
//===----------------------------------------------------------------------===//
-#ifndef LLVM_ANALYSIS_ALIAS_ANALYSIS_H
-#define LLVM_ANALYSIS_ALIAS_ANALYSIS_H
+#ifndef LLVM_ANALYSIS_ALIASANALYSIS_H
+#define LLVM_ANALYSIS_ALIASANALYSIS_H
-#include "llvm/Support/CallSite.h"
-#include <vector>
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/IR/CallSite.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/Analysis/MemoryLocation.h"
namespace llvm {
class LoadInst;
class StoreInst;
class VAArgInst;
-class TargetData;
+class DataLayout;
+class TargetLibraryInfo;
class Pass;
class AnalysisUsage;
+class MemTransferInst;
+class MemIntrinsic;
+class DominatorTree;
class AliasAnalysis {
protected:
- const TargetData *TD;
+ const DataLayout *DL;
+ const TargetLibraryInfo *TLI;
private:
AliasAnalysis *AA; // Previous Alias Analysis to chain to.
/// typically called by the run* methods of these subclasses. This may be
/// called multiple times.
///
- void InitializeAliasAnalysis(Pass *P);
+ void InitializeAliasAnalysis(Pass *P, const DataLayout *DL);
/// getAnalysisUsage - All alias analysis implementations should invoke this
/// directly (using AliasAnalysis::getAnalysisUsage(AU)).
public:
static char ID; // Class identification, replacement for typeinfo
- AliasAnalysis() : TD(0), AA(0) {}
+ AliasAnalysis() : DL(nullptr), TLI(nullptr), AA(nullptr) {}
virtual ~AliasAnalysis(); // We want to be subclassed
- /// UnknownSize - This is a special value which can be used with the
- /// size arguments in alias queries to indicate that the caller does not
- /// know the sizes of the potential memory references.
- static uint64_t const UnknownSize = ~UINT64_C(0);
-
- /// getTargetData - Return a pointer to the current TargetData object, or
- /// null if no TargetData object is available.
+ /// getTargetLibraryInfo - Return a pointer to the current TargetLibraryInfo
+ /// object, or null if no TargetLibraryInfo object is available.
///
- const TargetData *getTargetData() const { return TD; }
+ const TargetLibraryInfo *getTargetLibraryInfo() const { return TLI; }
- /// getTypeStoreSize - Return the TargetData store size for the given type,
+ /// getTypeStoreSize - Return the DataLayout store size for the given type,
/// if known, or a conservative value otherwise.
///
- uint64_t getTypeStoreSize(const Type *Ty);
+ uint64_t getTypeStoreSize(Type *Ty);
//===--------------------------------------------------------------------===//
/// Alias Queries...
///
- /// Location - A description of a memory location.
- struct Location {
- /// Ptr - The address of the start of the location.
- const Value *Ptr;
- /// Size - The maximum size of the location, or UnknownSize if the size is
- /// not known. Note that an unknown size does not mean the pointer aliases
- /// the entire virtual address space, because there are restrictions on
- /// stepping out of one object and into another.
- /// See http://llvm.org/docs/LangRef.html#pointeraliasing
- uint64_t Size;
- /// TBAATag - The metadata node which describes the TBAA type of
- /// the location, or null if there is no known unique tag.
- const MDNode *TBAATag;
-
- explicit Location(const Value *P = 0,
- uint64_t S = UnknownSize,
- const MDNode *N = 0)
- : Ptr(P), Size(S), TBAATag(N) {}
-
- Location getWithNewPtr(const Value *NewPtr) const {
- Location Copy(*this);
- Copy.Ptr = NewPtr;
- return Copy;
- }
-
- Location getWithoutTBAATag() const {
- Location Copy(*this);
- Copy.TBAATag = 0;
- return Copy;
- }
- };
-
/// Alias analysis result - Either we know for sure that it does not alias, we
/// know for sure it must alias, or we don't know anything: The two pointers
/// _might_ alias. This enum is designed so you can do things like:
/// See docs/AliasAnalysis.html for more information on the specific meanings
/// of these values.
///
- enum AliasResult { NoAlias = 0, MayAlias = 1, MustAlias = 2 };
+ enum AliasResult {
+ NoAlias = 0, ///< No dependencies.
+ MayAlias, ///< Anything goes.
+ PartialAlias, ///< Pointers differ, but pointees overlap.
+ MustAlias ///< Pointers are equal.
+ };
/// alias - The main low level interface to the alias analysis implementation.
/// Returns an AliasResult indicating whether the two pointers are aliased to
/// each other. This is the interface that must be implemented by specific
/// alias analysis implementations.
- virtual AliasResult alias(const Location &LocA, const Location &LocB);
+ virtual AliasResult alias(const MemoryLocation &LocA,
+ const MemoryLocation &LocB);
/// alias - A convenience wrapper.
AliasResult alias(const Value *V1, uint64_t V1Size,
const Value *V2, uint64_t V2Size) {
- return alias(Location(V1, V1Size), Location(V2, V2Size));
+ return alias(MemoryLocation(V1, V1Size), MemoryLocation(V2, V2Size));
}
/// alias - A convenience wrapper.
AliasResult alias(const Value *V1, const Value *V2) {
- return alias(V1, UnknownSize, V2, UnknownSize);
+ return alias(V1, MemoryLocation::UnknownSize, V2,
+ MemoryLocation::UnknownSize);
}
/// isNoAlias - A trivial helper function to check to see if the specified
/// pointers are no-alias.
- bool isNoAlias(const Location &LocA, const Location &LocB) {
+ bool isNoAlias(const MemoryLocation &LocA, const MemoryLocation &LocB) {
return alias(LocA, LocB) == NoAlias;
}
/// isNoAlias - A convenience wrapper.
bool isNoAlias(const Value *V1, uint64_t V1Size,
const Value *V2, uint64_t V2Size) {
- return isNoAlias(Location(V1, V1Size), Location(V2, V2Size));
+ return isNoAlias(MemoryLocation(V1, V1Size), MemoryLocation(V2, V2Size));
+ }
+
+ /// isNoAlias - A convenience wrapper.
+ bool isNoAlias(const Value *V1, const Value *V2) {
+ return isNoAlias(MemoryLocation(V1), MemoryLocation(V2));
+ }
+
+ /// isMustAlias - A convenience wrapper.
+ bool isMustAlias(const MemoryLocation &LocA, const MemoryLocation &LocB) {
+ return alias(LocA, LocB) == MustAlias;
}
+ /// isMustAlias - A convenience wrapper.
+ bool isMustAlias(const Value *V1, const Value *V2) {
+ return alias(V1, 1, V2, 1) == MustAlias;
+ }
+
/// pointsToConstantMemory - If the specified memory location is
/// known to be constant, return true. If OrLocal is true and the
/// specified memory location is known to be "local" (derived from
/// an alloca), return true. Otherwise return false.
- virtual bool pointsToConstantMemory(const Location &Loc,
+ virtual bool pointsToConstantMemory(const MemoryLocation &Loc,
bool OrLocal = false);
/// pointsToConstantMemory - A convenient wrapper.
bool pointsToConstantMemory(const Value *P, bool OrLocal = false) {
- return pointsToConstantMemory(Location(P), OrLocal);
+ return pointsToConstantMemory(MemoryLocation(P), OrLocal);
}
//===--------------------------------------------------------------------===//
/// This property corresponds to the IntrNoMem LLVM intrinsic flag.
DoesNotAccessMemory = Nowhere | NoModRef,
- /// AccessesArgumentsReadonly - This function loads through function
- /// arguments and does not perform any non-local stores or volatile
- /// loads.
+ /// OnlyReadsArgumentPointees - The only memory references in this function
+ /// (if it has any) are non-volatile loads from objects pointed to by its
+ /// pointer-typed arguments, with arbitrary offsets.
///
/// This property corresponds to the IntrReadArgMem LLVM intrinsic flag.
- AccessesArgumentsReadonly = ArgumentPointees | Ref,
+ OnlyReadsArgumentPointees = ArgumentPointees | Ref,
- /// AccessesArguments - This function accesses function arguments in well
- /// known (possibly volatile) ways, but does not access any other memory.
+ /// OnlyAccessesArgumentPointees - The only memory references in this
+ /// function (if it has any) are non-volatile loads and stores from objects
+ /// pointed to by its pointer-typed arguments, with arbitrary offsets.
///
/// This property corresponds to the IntrReadWriteArgMem LLVM intrinsic flag.
- AccessesArguments = ArgumentPointees | ModRef,
+ OnlyAccessesArgumentPointees = ArgumentPointees | ModRef,
/// OnlyReadsMemory - This function does not perform any non-local stores or
/// volatile loads, but may read from any memory location.
UnknownModRefBehavior = Anywhere | ModRef
};
+ /// Get the ModRef info associated with a pointer argument of a callsite. The
+ /// result's bits are set to indicate the allowed aliasing ModRef kinds. Note
+ /// that these bits do not necessarily account for the overall behavior of
+ /// the function, but rather only provide additional per-argument
+ /// information.
+ virtual ModRefResult getArgModRefInfo(ImmutableCallSite CS, unsigned ArgIdx);
+
/// getModRefBehavior - Return the behavior when calling the given call site.
virtual ModRefBehavior getModRefBehavior(ImmutableCallSite CS);
}
/// onlyAccessesArgPointees - Return true if functions with the specified
- /// behavior are known to read at most from objects pointed to by their
- /// pointer-typed arguments (with arbitrary offsets).
+ /// behavior are known to read and write at most from objects pointed to by
+ /// their pointer-typed arguments (with arbitrary offsets).
///
static bool onlyAccessesArgPointees(ModRefBehavior MRB) {
return !(MRB & Anywhere & ~ArgumentPointees);
}
+ /// doesAccessArgPointees - Return true if functions with the specified
+ /// behavior are known to potentially read or write from objects pointed
+ /// to be their pointer-typed arguments (with arbitrary offsets).
+ ///
+ static bool doesAccessArgPointees(ModRefBehavior MRB) {
+ return (MRB & ModRef) && (MRB & ArgumentPointees);
+ }
+
+ /// getModRefInfo - Return information about whether or not an
+ /// instruction may read or write memory (without regard to a
+ /// specific location)
+ ModRefResult getModRefInfo(const Instruction *I) {
+ if (auto CS = ImmutableCallSite(I)) {
+ auto MRB = getModRefBehavior(CS);
+ if (MRB & ModRef)
+ return ModRef;
+ else if (MRB & Ref)
+ return Ref;
+ else if (MRB & Mod)
+ return Mod;
+ return NoModRef;
+ }
+
+ return getModRefInfo(I, MemoryLocation());
+ }
+
/// getModRefInfo - Return information about whether or not an instruction may
/// read or write the specified memory location. An instruction
/// that doesn't read or write memory may be trivially LICM'd for example.
- ModRefResult getModRefInfo(const Instruction *I,
- const Location &Loc) {
+ ModRefResult getModRefInfo(const Instruction *I, const MemoryLocation &Loc) {
switch (I->getOpcode()) {
case Instruction::VAArg: return getModRefInfo((const VAArgInst*)I, Loc);
case Instruction::Load: return getModRefInfo((const LoadInst*)I, Loc);
case Instruction::Store: return getModRefInfo((const StoreInst*)I, Loc);
+ case Instruction::Fence: return getModRefInfo((const FenceInst*)I, Loc);
+ case Instruction::AtomicCmpXchg:
+ return getModRefInfo((const AtomicCmpXchgInst*)I, Loc);
+ case Instruction::AtomicRMW:
+ return getModRefInfo((const AtomicRMWInst*)I, Loc);
case Instruction::Call: return getModRefInfo((const CallInst*)I, Loc);
case Instruction::Invoke: return getModRefInfo((const InvokeInst*)I,Loc);
default: return NoModRef;
/// getModRefInfo - A convenience wrapper.
ModRefResult getModRefInfo(const Instruction *I,
const Value *P, uint64_t Size) {
- return getModRefInfo(I, Location(P, Size));
+ return getModRefInfo(I, MemoryLocation(P, Size));
}
- /// getModRefInfo (for call sites) - Return whether information about whether
+ /// getModRefInfo (for call sites) - Return information about whether
/// a particular call site modifies or reads the specified memory location.
virtual ModRefResult getModRefInfo(ImmutableCallSite CS,
- const Location &Loc);
+ const MemoryLocation &Loc);
/// getModRefInfo (for call sites) - A convenience wrapper.
ModRefResult getModRefInfo(ImmutableCallSite CS,
const Value *P, uint64_t Size) {
- return getModRefInfo(CS, Location(P, Size));
+ return getModRefInfo(CS, MemoryLocation(P, Size));
}
- /// getModRefInfo (for calls) - Return whether information about whether
+ /// getModRefInfo (for calls) - Return information about whether
/// a particular call modifies or reads the specified memory location.
- ModRefResult getModRefInfo(const CallInst *C, const Location &Loc) {
+ ModRefResult getModRefInfo(const CallInst *C, const MemoryLocation &Loc) {
return getModRefInfo(ImmutableCallSite(C), Loc);
}
/// getModRefInfo (for calls) - A convenience wrapper.
ModRefResult getModRefInfo(const CallInst *C, const Value *P, uint64_t Size) {
- return getModRefInfo(C, Location(P, Size));
+ return getModRefInfo(C, MemoryLocation(P, Size));
}
- /// getModRefInfo (for invokes) - Return whether information about whether
+ /// getModRefInfo (for invokes) - Return information about whether
/// a particular invoke modifies or reads the specified memory location.
- ModRefResult getModRefInfo(const InvokeInst *I,
- const Location &Loc) {
+ ModRefResult getModRefInfo(const InvokeInst *I, const MemoryLocation &Loc) {
return getModRefInfo(ImmutableCallSite(I), Loc);
}
/// getModRefInfo (for invokes) - A convenience wrapper.
ModRefResult getModRefInfo(const InvokeInst *I,
const Value *P, uint64_t Size) {
- return getModRefInfo(I, Location(P, Size));
+ return getModRefInfo(I, MemoryLocation(P, Size));
}
- /// getModRefInfo (for loads) - Return whether information about whether
+ /// getModRefInfo (for loads) - Return information about whether
/// a particular load modifies or reads the specified memory location.
- ModRefResult getModRefInfo(const LoadInst *L, const Location &Loc);
+ ModRefResult getModRefInfo(const LoadInst *L, const MemoryLocation &Loc);
/// getModRefInfo (for loads) - A convenience wrapper.
ModRefResult getModRefInfo(const LoadInst *L, const Value *P, uint64_t Size) {
- return getModRefInfo(L, Location(P, Size));
+ return getModRefInfo(L, MemoryLocation(P, Size));
}
- /// getModRefInfo (for stores) - Return whether information about whether
+ /// getModRefInfo (for stores) - Return information about whether
/// a particular store modifies or reads the specified memory location.
- ModRefResult getModRefInfo(const StoreInst *S, const Location &Loc);
+ ModRefResult getModRefInfo(const StoreInst *S, const MemoryLocation &Loc);
/// getModRefInfo (for stores) - A convenience wrapper.
- ModRefResult getModRefInfo(const StoreInst *S, const Value *P, uint64_t Size) {
- return getModRefInfo(S, Location(P, Size));
+ ModRefResult getModRefInfo(const StoreInst *S, const Value *P, uint64_t Size){
+ return getModRefInfo(S, MemoryLocation(P, Size));
+ }
+
+ /// getModRefInfo (for fences) - Return information about whether
+ /// a particular store modifies or reads the specified memory location.
+ ModRefResult getModRefInfo(const FenceInst *S, const MemoryLocation &Loc) {
+ // Conservatively correct. (We could possibly be a bit smarter if
+ // Loc is a alloca that doesn't escape.)
+ return ModRef;
+ }
+
+ /// getModRefInfo (for fences) - A convenience wrapper.
+ ModRefResult getModRefInfo(const FenceInst *S, const Value *P, uint64_t Size){
+ return getModRefInfo(S, MemoryLocation(P, Size));
+ }
+
+ /// getModRefInfo (for cmpxchges) - Return information about whether
+ /// a particular cmpxchg modifies or reads the specified memory location.
+ ModRefResult getModRefInfo(const AtomicCmpXchgInst *CX,
+ const MemoryLocation &Loc);
+
+ /// getModRefInfo (for cmpxchges) - A convenience wrapper.
+ ModRefResult getModRefInfo(const AtomicCmpXchgInst *CX,
+ const Value *P, unsigned Size) {
+ return getModRefInfo(CX, MemoryLocation(P, Size));
+ }
+
+ /// getModRefInfo (for atomicrmws) - Return information about whether
+ /// a particular atomicrmw modifies or reads the specified memory location.
+ ModRefResult getModRefInfo(const AtomicRMWInst *RMW,
+ const MemoryLocation &Loc);
+
+ /// getModRefInfo (for atomicrmws) - A convenience wrapper.
+ ModRefResult getModRefInfo(const AtomicRMWInst *RMW,
+ const Value *P, unsigned Size) {
+ return getModRefInfo(RMW, MemoryLocation(P, Size));
}
- /// getModRefInfo (for va_args) - Return whether information about whether
+ /// getModRefInfo (for va_args) - Return information about whether
/// a particular va_arg modifies or reads the specified memory location.
- ModRefResult getModRefInfo(const VAArgInst* I, const Location &Loc);
+ ModRefResult getModRefInfo(const VAArgInst *I, const MemoryLocation &Loc);
/// getModRefInfo (for va_args) - A convenience wrapper.
- ModRefResult getModRefInfo(const VAArgInst* I, const Value* P, uint64_t Size) {
- return getModRefInfo(I, Location(P, Size));
+ ModRefResult getModRefInfo(const VAArgInst* I, const Value* P, uint64_t Size){
+ return getModRefInfo(I, MemoryLocation(P, Size));
}
+ /// getModRefInfo - Return information about whether a call and an instruction
+ /// may refer to the same memory locations.
+ ModRefResult getModRefInfo(Instruction *I,
+ ImmutableCallSite Call);
/// getModRefInfo - Return information about whether two call sites may refer
/// to the same set of memory locations. See
virtual ModRefResult getModRefInfo(ImmutableCallSite CS1,
ImmutableCallSite CS2);
+ /// callCapturesBefore - Return information about whether a particular call
+ /// site modifies or reads the specified memory location.
+ ModRefResult callCapturesBefore(const Instruction *I,
+ const MemoryLocation &MemLoc,
+ DominatorTree *DT);
+
+ /// callCapturesBefore - A convenience wrapper.
+ ModRefResult callCapturesBefore(const Instruction *I, const Value *P,
+ uint64_t Size, DominatorTree *DT) {
+ return callCapturesBefore(I, MemoryLocation(P, Size), DT);
+ }
+
//===--------------------------------------------------------------------===//
/// Higher level methods for querying mod/ref information.
///
/// canBasicBlockModify - Return true if it is possible for execution of the
- /// specified basic block to modify the value pointed to by Ptr.
- bool canBasicBlockModify(const BasicBlock &BB, const Location &Loc);
+ /// specified basic block to modify the location Loc.
+ bool canBasicBlockModify(const BasicBlock &BB, const MemoryLocation &Loc);
/// canBasicBlockModify - A convenience wrapper.
bool canBasicBlockModify(const BasicBlock &BB, const Value *P, uint64_t Size){
- return canBasicBlockModify(BB, Location(P, Size));
+ return canBasicBlockModify(BB, MemoryLocation(P, 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 canInstructionRangeModify(const Instruction &I1, const Instruction &I2,
- const Location &Loc);
-
- /// canInstructionRangeModify - A convenience wrapper.
- bool canInstructionRangeModify(const Instruction &I1, const Instruction &I2,
- const Value *Ptr, uint64_t Size) {
- return canInstructionRangeModify(I1, I2, Location(Ptr, Size));
+ /// canInstructionRangeModRef - Return true if it is possible for the
+ /// execution of the specified instructions to mod\ref (according to the
+ /// mode) the location Loc. 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 canInstructionRangeModRef(const Instruction &I1, const Instruction &I2,
+ const MemoryLocation &Loc,
+ const ModRefResult Mode);
+
+ /// canInstructionRangeModRef - A convenience wrapper.
+ bool canInstructionRangeModRef(const Instruction &I1,
+ const Instruction &I2, const Value *Ptr,
+ uint64_t Size, const ModRefResult Mode) {
+ return canInstructionRangeModRef(I1, I2, MemoryLocation(Ptr, Size), Mode);
}
//===--------------------------------------------------------------------===//
///
virtual void copyValue(Value *From, Value *To);
+ /// addEscapingUse - This method should be used whenever an escaping use is
+ /// added to a pointer value. Analysis implementations may either return
+ /// conservative responses for that value in the future, or may recompute
+ /// some or all internal state to continue providing precise responses.
+ ///
+ /// Escaping uses are considered by anything _except_ the following:
+ /// - GEPs or bitcasts of the pointer
+ /// - Loads through the pointer
+ /// - Stores through (but not of) the pointer
+ virtual void addEscapingUse(Use &U);
+
/// replaceWithNewValue - This method is the obvious combination of the two
/// above, and it provided as a helper to simplify client code.
///
/// function.
bool isNoAliasCall(const Value *V);
+/// isNoAliasArgument - Return true if this is an argument with the noalias
+/// attribute.
+bool isNoAliasArgument(const Value *V);
+
/// 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
+/// Allocas
/// ByVal and NoAlias Arguments
-/// NoAlias returns
+/// NoAlias returns (e.g. calls to malloc)
///
bool isIdentifiedObject(const Value *V);
-} // End llvm namespace
+/// isIdentifiedFunctionLocal - Return true if V is umabigously identified
+/// at the function-level. Different IdentifiedFunctionLocals can't alias.
+/// Further, an IdentifiedFunctionLocal can not alias with any function
+/// arguments other than itself, which is not necessarily true for
+/// IdentifiedObjects.
+bool isIdentifiedFunctionLocal(const Value *V);
+
+} // namespace llvm
#endif