// 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 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:
- 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.
- ///
- const TargetData *getTargetData() const { return TD; }
-
- /// getTypeStoreSize - Return the TargetData store size for the given type,
- /// if known, or a conservative value otherwise.
+ /// getTargetLibraryInfo - Return a pointer to the current TargetLibraryInfo
+ /// object, or null if no TargetLibraryInfo object is available.
///
- uint64_t getTypeStoreSize(const Type *Ty);
+ const TargetLibraryInfo *getTargetLibraryInfo() const { return TLI; }
//===--------------------------------------------------------------------===//
- /// Alias Queries...
- ///
+ /// \name 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:
- /// 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, MayAlias = 1, MustAlias = 2 };
-
- /// 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));
+ }
+
+ /// A convenience wrapper around the \c isNoAlias helper interface.
+ bool isNoAlias(const Value *V1, const Value *V2) {
+ return isNoAlias(MemoryLocation(V1), MemoryLocation(V2));
}
- /// 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,
+ /// 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;
+ }
+
+ /// A convenience wrapper around the \c isMustAlias helper interface.
+ bool isMustAlias(const Value *V1, const Value *V2) {
+ return alias(V1, 1, V2, 1) == MustAlias;
+ }
+
+ /// 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...
- ///
+ /// \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 ModRefInfo getArgModRefInfo(ImmutableCallSite CS, unsigned ArgIdx);
- /// ModRefResult - Represent the result of a mod/ref query. Mod and Ref are
- /// bits which may be or'd together.
+ /// Return the behavior of the given call site.
+ virtual FunctionModRefBehavior getModRefBehavior(ImmutableCallSite CS);
+
+ /// Return the behavior when calling the given function.
+ virtual FunctionModRefBehavior getModRefBehavior(const Function *F);
+
+ /// Checks if the specified call is known to never read or write memory.
///
- enum ModRefResult { NoModRef = 0, Ref = 1, Mod = 2, ModRef = 3 };
-
-
- /// 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,
-
- // AccessesArgumentsReadonly - This function loads through function
- // arguments and does not perform any non-local stores or volatile
- // loads.
- //
- // This property corresponds to the IntrReadArgMem LLVM intrinsic flag.
- AccessesArgumentsReadonly,
-
- // AccessesArguments - This function accesses function arguments in well
- // known (possibly volatile) ways, but does not access any other memory.
- //
- // This property corresponds to the IntrReadWriteArgMem LLVM intrinsic flag.
- AccessesArguments,
-
- // 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,
-
- // UnknownModRefBehavior - This indicates that the function could not be
- // classified into one of the behaviors above.
- UnknownModRefBehavior
- };
-
- /// getModRefBehavior - Return the behavior when calling the given call site.
- virtual ModRefBehavior 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);
-
- /// 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.
+ /// 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).
+ ///
+ /// Functions 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(const Function *F) {
return onlyReadsMemory(getModRefBehavior(F));
}
- /// onlyReadsMemory - If the functions with the specified behavior are 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.
- ///
- static bool onlyReadsMemory(ModRefBehavior MRB) {
- return MRB == DoesNotAccessMemory ||
- MRB == AccessesArgumentsReadonly ||
- MRB == OnlyReadsMemory;
+ /// 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::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 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);
+ 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 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) {
+ 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 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) {
+ 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 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);
+ 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 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);
+ 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.
+ 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 MRI_ModRef;
}
- /// getModRefInfo (for va_args) - Return whether information about whether
+ /// getModRefInfo (for fences) - A convenience wrapper.
+ 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.
+ ModRefInfo getModRefInfo(const AtomicCmpXchgInst *CX,
+ const MemoryLocation &Loc);
+
+ /// getModRefInfo (for cmpxchges) - A convenience wrapper.
+ 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.
+ ModRefInfo getModRefInfo(const AtomicRMWInst *RMW, const MemoryLocation &Loc);
+
+ /// getModRefInfo (for atomicrmws) - A convenience wrapper.
+ 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 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);
-
- //===--------------------------------------------------------------------===//
- /// Higher level methods for querying mod/ref information.
+ /// 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;
+ }
- /// 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);
+ return getModRefInfo(I, MemoryLocation());
+ }
- /// canBasicBlockModify - A convenience wrapper.
- bool canBasicBlockModify(const BasicBlock &BB, const Value *P, uint64_t Size){
- return canBasicBlockModify(BB, Location(P, Size));
+ /// 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;
+ }
}
- /// 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);
+ /// 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));
+ }
+
+ /// Return information about whether a call and an instruction may refer to
+ /// the same memory locations.
+ ModRefInfo getModRefInfo(Instruction *I, ImmutableCallSite Call);
- /// 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));
+ /// 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);
+
+ /// \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));
+ }
- /// 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);
}
};
/// 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);
+/// 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);
+
} // End llvm namespace
#endif
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