// which automatically provides functionality for the entire suite of client
// APIs.
//
-// This API identifies memory regions with the Location class. The pointer
+// 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 UnknownSize if
-// the size is not known. The TBAA tag identifies the "type" of the memory
-// reference; see the TypeBasedAliasAnalysis class for details.
+// 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
class MemTransferInst;
class MemIntrinsic;
class DominatorTree;
+class OrderedBasicBlock;
+
+/// The possible results of an alias query.
+///
+/// These results are always computed between two MemoryLocation objects as
+/// a query to some alias analysis.
+///
+/// Note that these are unscoped enumerations because we would like to support
+/// implicitly testing a result for the existence of any possible aliasing with
+/// a conversion to bool, but an "enum class" doesn't support this. The
+/// canonical names from the literature are suffixed and unique anyways, and so
+/// they serve as global constants in LLVM for these results.
+///
+/// See docs/AliasAnalysis.html for more information on the specific meanings
+/// of these values.
+enum AliasResult {
+ /// The two locations do not alias at all.
+ ///
+ /// This value is arranged to convert to false, while all other values
+ /// convert to true. This allows a boolean context to convert the result to
+ /// a binary flag indicating whether there is the possibility of aliasing.
+ NoAlias = 0,
+ /// The two locations may or may not alias. This is the least precise result.
+ MayAlias,
+ /// The two locations alias, but only due to a partial overlap.
+ PartialAlias,
+ /// The two locations precisely alias each other.
+ MustAlias,
+};
+
+/// Flags indicating whether a memory access modifies or references memory.
+///
+/// This is no access at all, a modification, a reference, or both
+/// a modification and a reference. These are specifically structured such that
+/// they form a two bit matrix and bit-tests for 'mod' or 'ref' work with any
+/// of the possible values.
+enum ModRefInfo {
+ /// The access neither references nor modifies the value stored in memory.
+ MRI_NoModRef = 0,
+ /// The access references the value stored in memory.
+ MRI_Ref = 1,
+ /// The access modifies the value stored in memory.
+ MRI_Mod = 2,
+ /// The access both references and modifies the value stored in memory.
+ MRI_ModRef = MRI_Ref | MRI_Mod
+};
+
+/// The locations at which a function might access memory.
+///
+/// These are primarily used in conjunction with the \c AccessKind bits to
+/// describe both the nature of access and the locations of access for a
+/// function call.
+enum FunctionModRefLocation {
+ /// Base case is no access to memory.
+ FMRL_Nowhere = 0,
+ /// Access to memory via argument pointers.
+ FMRL_ArgumentPointees = 4,
+ /// Access to any memory.
+ FMRL_Anywhere = 8 | FMRL_ArgumentPointees
+};
+
+/// Summary of how a function affects memory in the program.
+///
+/// Loads from constant globals are not considered memory accesses for this
+/// interface. Also, functions may freely modify stack space local to their
+/// invocation without having to report it through these interfaces.
+enum FunctionModRefBehavior {
+ /// This function does not perform any non-local loads or stores to memory.
+ ///
+ /// This property corresponds to the GCC 'const' attribute.
+ /// This property corresponds to the LLVM IR 'readnone' attribute.
+ /// This property corresponds to the IntrNoMem LLVM intrinsic flag.
+ FMRB_DoesNotAccessMemory = FMRL_Nowhere | MRI_NoModRef,
+
+ /// 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.
+ FMRB_OnlyReadsArgumentPointees = FMRL_ArgumentPointees | MRI_Ref,
+
+ /// 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.
+ FMRB_OnlyAccessesArgumentPointees = FMRL_ArgumentPointees | MRI_ModRef,
+
+ /// This function does not perform any non-local stores or volatile loads,
+ /// but may read from any memory location.
+ ///
+ /// This property corresponds to the GCC 'pure' attribute.
+ /// This property corresponds to the LLVM IR 'readonly' attribute.
+ /// This property corresponds to the IntrReadMem LLVM intrinsic flag.
+ FMRB_OnlyReadsMemory = FMRL_Anywhere | MRI_Ref,
+
+ /// This indicates that the function could not be classified into one of the
+ /// behaviors above.
+ FMRB_UnknownModRefBehavior = FMRL_Anywhere | MRI_ModRef
+};
class AliasAnalysis {
protected:
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 = MemoryLocation::UnknownSize;
-
/// getTargetLibraryInfo - Return a pointer to the current TargetLibraryInfo
/// object, or null if no TargetLibraryInfo object is available.
///
const TargetLibraryInfo *getTargetLibraryInfo() const { return TLI; }
- /// getTypeStoreSize - Return the DataLayout store size for the given type,
- /// if known, or a conservative value otherwise.
- ///
- uint64_t getTypeStoreSize(Type *Ty);
-
//===--------------------------------------------------------------------===//
- /// Alias Queries...
- ///
+ /// \name Alias Queries
+ /// @{
- /// Legacy typedef for the AA location object. New code should use \c
- /// MemoryLocation directly.
- typedef MemoryLocation Location;
-
- /// 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:
- /// if (AA.alias(P1, P2)) { ... }
- /// to check to see if two pointers might alias.
- ///
- /// See docs/AliasAnalysis.html for more information on the specific meanings
- /// of these values.
- ///
- 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.
+ /// 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
+ /// 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));
+ /// A convenience wrapper around the primary \c alias interface.
+ AliasResult alias(const Value *V1, uint64_t V1Size, const Value *V2,
+ uint64_t V2Size) {
+ return alias(MemoryLocation(V1, V1Size), MemoryLocation(V2, V2Size));
}
- /// alias - A convenience wrapper.
+ /// A convenience wrapper around the primary \c alias interface.
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) {
+ /// A trivial helper function to check to see if the specified pointers are
+ /// no-alias.
+ 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));
+ /// A convenience wrapper around the \c isNoAlias helper interface.
+ bool isNoAlias(const Value *V1, uint64_t V1Size, const Value *V2,
+ uint64_t V2Size) {
+ return isNoAlias(MemoryLocation(V1, V1Size), MemoryLocation(V2, V2Size));
}
-
- /// isNoAlias - A convenience wrapper.
+
+ /// A convenience wrapper around the \c isNoAlias helper interface.
bool isNoAlias(const Value *V1, const Value *V2) {
- return isNoAlias(Location(V1), Location(V2));
+ return isNoAlias(MemoryLocation(V1), MemoryLocation(V2));
}
-
- /// isMustAlias - A convenience wrapper.
- bool isMustAlias(const Location &LocA, const Location &LocB) {
+
+ /// A trivial helper function to check to see if the specified pointers are
+ /// must-alias.
+ bool isMustAlias(const MemoryLocation &LocA, const MemoryLocation &LocB) {
return alias(LocA, LocB) == MustAlias;
}
- /// isMustAlias - A convenience wrapper.
+ /// A convenience wrapper around the \c isMustAlias helper interface.
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,
+
+ /// Checks whether the given location points to constant memory, or if
+ /// \p OrLocal is true whether it points to a local alloca.
+ virtual bool pointsToConstantMemory(const MemoryLocation &Loc,
bool OrLocal = false);
- /// pointsToConstantMemory - A convenient wrapper.
+ /// A convenience wrapper around the primary \c pointsToConstantMemory
+ /// interface.
bool pointsToConstantMemory(const Value *P, bool OrLocal = false) {
- return pointsToConstantMemory(Location(P), OrLocal);
+ return pointsToConstantMemory(MemoryLocation(P), OrLocal);
}
+ /// @}
//===--------------------------------------------------------------------===//
- /// Simple mod/ref information...
- ///
-
- /// ModRefResult - Represent the result of a mod/ref query. Mod and Ref are
- /// bits which may be or'd together.
- ///
- enum ModRefResult { NoModRef = 0, Ref = 1, Mod = 2, ModRef = 3 };
-
- /// These values define additional bits used to define the
- /// ModRefBehavior values.
- enum { Nowhere = 0, ArgumentPointees = 4, Anywhere = 8 | ArgumentPointees };
-
- /// ModRefBehavior - Summary of how a function affects memory in the program.
- /// Loads from constant globals are not considered memory accesses for this
- /// interface. Also, functions may freely modify stack space local to their
- /// invocation without having to report it through these interfaces.
- enum ModRefBehavior {
- /// DoesNotAccessMemory - This function does not perform any non-local loads
- /// or stores to memory.
- ///
- /// This property corresponds to the GCC 'const' attribute.
- /// This property corresponds to the LLVM IR 'readnone' attribute.
- /// This property corresponds to the IntrNoMem LLVM intrinsic flag.
- DoesNotAccessMemory = Nowhere | NoModRef,
-
- /// 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.
- OnlyReadsArgumentPointees = ArgumentPointees | Ref,
-
- /// 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.
- OnlyAccessesArgumentPointees = ArgumentPointees | ModRef,
-
- /// OnlyReadsMemory - This function does not perform any non-local stores or
- /// volatile loads, but may read from any memory location.
- ///
- /// This property corresponds to the GCC 'pure' attribute.
- /// This property corresponds to the LLVM IR 'readonly' attribute.
- /// This property corresponds to the IntrReadMem LLVM intrinsic flag.
- OnlyReadsMemory = Anywhere | Ref,
-
- /// UnknownModRefBehavior - This indicates that the function could not be
- /// classified into one of the behaviors above.
- UnknownModRefBehavior = Anywhere | ModRef
- };
+ /// \name Simple mod/ref information
+ /// @{
/// 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);
+ virtual ModRefInfo getArgModRefInfo(ImmutableCallSite CS, unsigned ArgIdx);
- /// getModRefBehavior - Return the behavior when calling the given call site.
- virtual ModRefBehavior getModRefBehavior(ImmutableCallSite CS);
+ /// Return the behavior of the given call site.
+ virtual FunctionModRefBehavior getModRefBehavior(ImmutableCallSite CS);
- /// getModRefBehavior - Return the behavior when calling the given function.
- /// For use when the call site is not known.
- virtual ModRefBehavior getModRefBehavior(const Function *F);
+ /// Return the behavior when calling the given function.
+ virtual FunctionModRefBehavior getModRefBehavior(const Function *F);
- /// doesNotAccessMemory - If the specified call is known to never read or
- /// write memory, return true. If the call only reads from known-constant
- /// memory, it is also legal to return true. Calls that unwind the stack
- /// are legal for this predicate.
+ /// Checks if the specified call is known to never read or write memory.
+ ///
+ /// Note that if the call only reads from known-constant memory, it is also
+ /// legal to return true. Also, calls that unwind the stack are legal for
+ /// this predicate.
///
/// Many optimizations (such as CSE and LICM) can be performed on such calls
/// without worrying about aliasing properties, and many calls have this
/// property (e.g. calls to 'sin' and 'cos').
///
/// This property corresponds to the GCC 'const' attribute.
- ///
bool doesNotAccessMemory(ImmutableCallSite CS) {
- return getModRefBehavior(CS) == DoesNotAccessMemory;
+ return getModRefBehavior(CS) == FMRB_DoesNotAccessMemory;
}
- /// doesNotAccessMemory - If the specified function is known to never read or
- /// write memory, return true. For use when the call site is not known.
+ /// Checks if the specified function is known to never read or write memory.
///
+ /// Note that if the function only reads from known-constant memory, it is
+ /// also legal to return true. Also, function that unwind the stack are legal
+ /// for this predicate.
+ ///
+ /// Many optimizations (such as CSE and LICM) can be performed on such calls
+ /// to such functions without worrying about aliasing properties, and many
+ /// functions have this property (e.g. 'sin' and 'cos').
+ ///
+ /// This property corresponds to the GCC 'const' attribute.
bool doesNotAccessMemory(const Function *F) {
- return getModRefBehavior(F) == DoesNotAccessMemory;
+ return getModRefBehavior(F) == FMRB_DoesNotAccessMemory;
}
- /// onlyReadsMemory - If the specified call is known to only read from
- /// non-volatile memory (or not access memory at all), return true. Calls
- /// that unwind the stack are legal for this predicate.
+ /// Checks if the specified call is known to only read from non-volatile
+ /// memory (or not access memory at all).
+ ///
+ /// Calls that unwind the stack are legal for this predicate.
///
/// This property allows many common optimizations to be performed in the
/// absence of interfering store instructions, such as CSE of strlen calls.
///
/// This property corresponds to the GCC 'pure' attribute.
- ///
bool onlyReadsMemory(ImmutableCallSite CS) {
return onlyReadsMemory(getModRefBehavior(CS));
}
- /// onlyReadsMemory - If the specified function is known to only read from
- /// non-volatile memory (or not access memory at all), return true. For use
- /// when the call site is not known.
+ /// Checks if the specified function is known to only read from non-volatile
+ /// memory (or not access memory at all).
///
- bool onlyReadsMemory(const Function *F) {
- return onlyReadsMemory(getModRefBehavior(F));
- }
-
- /// onlyReadsMemory - Return true if functions with the specified behavior are
- /// known to only read from non-volatile memory (or not access memory at all).
- ///
- static bool onlyReadsMemory(ModRefBehavior MRB) {
- return !(MRB & Mod);
- }
-
- /// onlyAccessesArgPointees - Return true if functions with the specified
- /// behavior are known to read and write at most from objects pointed to by
- /// their pointer-typed arguments (with arbitrary offsets).
+ /// Functions that unwind the stack are legal for this predicate.
///
- 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).
+ /// This property allows many common optimizations to be performed in the
+ /// absence of interfering store instructions, such as CSE of strlen calls.
///
- static bool doesAccessArgPointees(ModRefBehavior MRB) {
- return (MRB & ModRef) && (MRB & ArgumentPointees);
+ /// This property corresponds to the GCC 'pure' attribute.
+ bool onlyReadsMemory(const Function *F) {
+ return onlyReadsMemory(getModRefBehavior(F));
}
- /// 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, Location());
+ /// Checks if functions with the specified behavior are known to only read
+ /// from non-volatile memory (or not access memory at all).
+ static bool onlyReadsMemory(FunctionModRefBehavior MRB) {
+ return !(MRB & MRI_Mod);
}
- /// 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) {
- 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;
- }
+ /// Checks if functions with the specified behavior are known to read and
+ /// write at most from objects pointed to by their pointer-typed arguments
+ /// (with arbitrary offsets).
+ static bool onlyAccessesArgPointees(FunctionModRefBehavior MRB) {
+ return !(MRB & FMRL_Anywhere & ~FMRL_ArgumentPointees);
}
- /// getModRefInfo - A convenience wrapper.
- ModRefResult getModRefInfo(const Instruction *I,
- const Value *P, uint64_t Size) {
- return getModRefInfo(I, Location(P, Size));
+ /// Checks 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(FunctionModRefBehavior MRB) {
+ return (MRB & MRI_ModRef) && (MRB & FMRL_ArgumentPointees);
}
/// 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);
+ virtual ModRefInfo getModRefInfo(ImmutableCallSite CS,
+ 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));
+ ModRefInfo getModRefInfo(ImmutableCallSite CS, const Value *P,
+ uint64_t Size) {
+ return getModRefInfo(CS, MemoryLocation(P, Size));
}
/// 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) {
+ ModRefInfo 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));
+ ModRefInfo getModRefInfo(const CallInst *C, const Value *P, uint64_t Size) {
+ return getModRefInfo(C, MemoryLocation(P, Size));
}
/// 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) {
+ ModRefInfo 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));
+ ModRefInfo getModRefInfo(const InvokeInst *I, const Value *P, uint64_t Size) {
+ return getModRefInfo(I, MemoryLocation(P, Size));
}
/// 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);
+ ModRefInfo 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));
+ ModRefInfo getModRefInfo(const LoadInst *L, const Value *P, uint64_t Size) {
+ return getModRefInfo(L, MemoryLocation(P, Size));
}
/// 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);
+ ModRefInfo 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));
+ ModRefInfo 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 Location &Loc) {
+ ModRefInfo 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;
+ return MRI_ModRef;
}
/// getModRefInfo (for fences) - A convenience wrapper.
- ModRefResult getModRefInfo(const FenceInst *S, const Value *P, uint64_t Size){
- return getModRefInfo(S, Location(P, Size));
+ ModRefInfo 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 Location &Loc);
+ ModRefInfo 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, Location(P, Size));
+ ModRefInfo 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 Location &Loc);
+ ModRefInfo 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, Location(P, Size));
+ ModRefInfo getModRefInfo(const AtomicRMWInst *RMW, const Value *P,
+ unsigned Size) {
+ return getModRefInfo(RMW, MemoryLocation(P, Size));
}
/// 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);
+ ModRefInfo 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));
+ ModRefInfo 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
- /// http://llvm.org/docs/AliasAnalysis.html#ModRefInfo
- /// for details.
- 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 AliasAnalysis::Location &MemLoc,
- DominatorTree *DT);
+ /// Check whether or not an instruction may read or write memory (without
+ /// regard to a specific location).
+ ///
+ /// For function calls, this delegates to the alias-analysis specific
+ /// call-site mod-ref behavior queries. Otherwise it delegates to the generic
+ /// mod ref information query without a location.
+ ModRefInfo getModRefInfo(const Instruction *I) {
+ if (auto CS = ImmutableCallSite(I)) {
+ auto MRB = getModRefBehavior(CS);
+ if (MRB & MRI_ModRef)
+ return MRI_ModRef;
+ else if (MRB & MRI_Ref)
+ return MRI_Ref;
+ else if (MRB & MRI_Mod)
+ return MRI_Mod;
+ return MRI_NoModRef;
+ }
- /// callCapturesBefore - A convenience wrapper.
- ModRefResult callCapturesBefore(const Instruction *I, const Value *P,
- uint64_t Size, DominatorTree *DT) {
- return callCapturesBefore(I, Location(P, Size), DT);
+ return getModRefInfo(I, MemoryLocation());
}
- //===--------------------------------------------------------------------===//
- /// Higher level methods for querying mod/ref information.
+ /// Check 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.
+ ///
+ /// This primarily delegates to specific helpers above.
+ ModRefInfo 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 MRI_NoModRef;
+ }
+ }
- /// canBasicBlockModify - Return true if it is possible for execution of the
- /// specified basic block to modify the location Loc.
- bool canBasicBlockModify(const BasicBlock &BB, const Location &Loc);
-
- /// canBasicBlockModify - A convenience wrapper.
- bool canBasicBlockModify(const BasicBlock &BB, const Value *P, uint64_t Size){
- return canBasicBlockModify(BB, Location(P, Size));
+ /// A convenience wrapper for constructing the memory location.
+ ModRefInfo getModRefInfo(const Instruction *I, const Value *P,
+ uint64_t Size) {
+ return getModRefInfo(I, MemoryLocation(P, 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 Location &Loc,
- const ModRefResult Mode);
+ /// Return information about whether a call and an instruction may refer to
+ /// the same memory locations.
+ ModRefInfo getModRefInfo(Instruction *I, ImmutableCallSite Call);
+
+ /// Return information about whether two call sites may refer to the same set
+ /// of memory locations. See the AA documentation for details:
+ /// http://llvm.org/docs/AliasAnalysis.html#ModRefInfo
+ virtual ModRefInfo getModRefInfo(ImmutableCallSite CS1,
+ ImmutableCallSite CS2);
- /// 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, Location(Ptr, Size), Mode);
+ /// \brief Return information about whether a particular call site modifies
+ /// or reads the specified memory location \p MemLoc before instruction \p I
+ /// in a BasicBlock. A ordered basic block \p OBB can be used to speed up
+ /// instruction ordering queries inside the BasicBlock containing \p I.
+ ModRefInfo callCapturesBefore(const Instruction *I,
+ const MemoryLocation &MemLoc, DominatorTree *DT,
+ OrderedBasicBlock *OBB = nullptr);
+
+ /// \brief A convenience wrapper to synthesize a memory location.
+ ModRefInfo callCapturesBefore(const Instruction *I, const Value *P,
+ uint64_t Size, DominatorTree *DT,
+ OrderedBasicBlock *OBB = nullptr) {
+ return callCapturesBefore(I, MemoryLocation(P, Size), DT, OBB);
}
+ /// @}
//===--------------------------------------------------------------------===//
- /// Methods that clients should call when they transform the program to allow
- /// alias analyses to update their internal data structures. Note that these
- /// methods may be called on any instruction, regardless of whether or not
- /// they have pointer-analysis implications.
- ///
+ /// \name Higher level methods for querying mod/ref information.
+ /// @{
- /// deleteValue - This method should be called whenever an LLVM Value is
- /// deleted from the program, for example when an instruction is found to be
- /// redundant and is eliminated.
- ///
- virtual void deleteValue(Value *V);
+ /// Check if it is possible for execution of the specified basic block to
+ /// modify the location Loc.
+ bool canBasicBlockModify(const BasicBlock &BB, const MemoryLocation &Loc);
- /// copyValue - This method should be used whenever a preexisting value in the
- /// program is copied or cloned, introducing a new value. Note that analysis
- /// implementations should tolerate clients that use this method to introduce
- /// the same value multiple times: if the analysis already knows about a
- /// value, it should ignore the request.
- ///
- virtual void copyValue(Value *From, Value *To);
+ /// A convenience wrapper synthesizing a memory location.
+ bool canBasicBlockModify(const BasicBlock &BB, const Value *P,
+ uint64_t Size) {
+ return canBasicBlockModify(BB, MemoryLocation(P, Size));
+ }
- /// 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.
+ /// Check if it is possible for the execution of the specified instructions
+ /// to mod\ref (according to the mode) the location Loc.
///
- void replaceWithNewValue(Value *Old, Value *New) {
- copyValue(Old, New);
- deleteValue(Old);
+ /// 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 ModRefInfo Mode);
+
+ /// A convenience wrapper synthesizing a memory location.
+ bool canInstructionRangeModRef(const Instruction &I1, const Instruction &I2,
+ const Value *Ptr, uint64_t Size,
+ const ModRefInfo Mode) {
+ return canInstructionRangeModRef(I1, I2, MemoryLocation(Ptr, Size), Mode);
}
};
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