| //===- CallPromotionUtils.h - Utilities for call promotion ------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file declares utilities useful for promoting indirect call sites to |
| // direct call sites. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_TRANSFORMS_UTILS_CALLPROMOTIONUTILS_H |
| #define LLVM_TRANSFORMS_UTILS_CALLPROMOTIONUTILS_H |
| |
| namespace llvm { |
| class CallBase; |
| class CastInst; |
| class Function; |
| class MDNode; |
| |
| /// Return true if the given indirect call site can be made to call \p Callee. |
| /// |
| /// This function ensures that the number and type of the call site's arguments |
| /// and return value match those of the given function. If the types do not |
| /// match exactly, they must at least be bitcast compatible. If \p FailureReason |
| /// is non-null and the indirect call cannot be promoted, the failure reason |
| /// will be stored in it. |
| bool isLegalToPromote(const CallBase &CB, Function *Callee, |
| const char **FailureReason = nullptr); |
| |
| /// Promote the given indirect call site to unconditionally call \p Callee. |
| /// |
| /// This function promotes the given call site, returning the direct call or |
| /// invoke instruction. If the function type of the call site doesn't match that |
| /// of the callee, bitcast instructions are inserted where appropriate. If \p |
| /// RetBitCast is non-null, it will be used to store the return value bitcast, |
| /// if created. |
| CallBase &promoteCall(CallBase &CB, Function *Callee, |
| CastInst **RetBitCast = nullptr); |
| |
| /// Promote the given indirect call site to conditionally call \p Callee. |
| /// |
| /// This function creates an if-then-else structure at the location of the call |
| /// site. The original call site is moved into the "else" block. A clone of the |
| /// indirect call site is promoted, placed in the "then" block, and returned. If |
| /// \p BranchWeights is non-null, it will be used to set !prof metadata on the |
| /// new conditional branch. |
| CallBase &promoteCallWithIfThenElse(CallBase &CB, Function *Callee, |
| MDNode *BranchWeights = nullptr); |
| |
| /// Try to promote (devirtualize) a virtual call on an Alloca. Return true on |
| /// success. |
| /// |
| /// Look for a pattern like: |
| /// |
| /// %o = alloca %class.Impl |
| /// %1 = getelementptr %class.Impl, %class.Impl* %o, i64 0, i32 0, i32 0 |
| /// store i32 (...)** bitcast (i8** getelementptr inbounds |
| /// ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV4Impl, i64 0, inrange i32 0, i64 2) |
| /// to i32 (...)**), i32 (...)*** %1 |
| /// %2 = getelementptr inbounds %class.Impl, %class.Impl* %o, i64 0, i32 0 |
| /// %3 = bitcast %class.Interface* %2 to void (%class.Interface*)*** |
| /// %vtable.i = load void (%class.Interface*)**, void (%class.Interface*)*** %3 |
| /// %4 = load void (%class.Interface*)*, void (%class.Interface*)** %vtable.i |
| /// call void %4(%class.Interface* nonnull %2) |
| /// |
| /// @_ZTV4Impl = linkonce_odr dso_local unnamed_addr constant { [3 x i8*] } |
| /// { [3 x i8*] |
| /// [i8* null, i8* bitcast ({ i8*, i8*, i8* }* @_ZTI4Impl to i8*), |
| /// i8* bitcast (void (%class.Impl*)* @_ZN4Impl3RunEv to i8*)] } |
| /// |
| bool tryPromoteCall(CallBase &CB); |
| |
| } // end namespace llvm |
| |
| #endif // LLVM_TRANSFORMS_UTILS_CALLPROMOTIONUTILS_H |