| //===- TypeMetadataUtils.h - Utilities related to type metadata --*- 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 contains functions that make it easier to manipulate type metadata |
| // for devirtualization. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_ANALYSIS_TYPEMETADATAUTILS_H |
| #define LLVM_ANALYSIS_TYPEMETADATAUTILS_H |
| |
| #include "llvm/ADT/SmallVector.h" |
| #include <cstdint> |
| |
| namespace llvm { |
| |
| class CallBase; |
| class CallInst; |
| class Constant; |
| class Function; |
| class DominatorTree; |
| class Instruction; |
| class Module; |
| |
| /// The type of CFI jumptable needed for a function. |
| enum CfiFunctionLinkage { |
| CFL_Definition = 0, |
| CFL_Declaration = 1, |
| CFL_WeakDeclaration = 2 |
| }; |
| |
| /// A call site that could be devirtualized. |
| struct DevirtCallSite { |
| /// The offset from the address point to the virtual function. |
| uint64_t Offset; |
| /// The call site itself. |
| CallBase &CB; |
| }; |
| |
| /// Given a call to the intrinsic \@llvm.type.test, find all devirtualizable |
| /// call sites based on the call and return them in DevirtCalls. |
| void findDevirtualizableCallsForTypeTest( |
| SmallVectorImpl<DevirtCallSite> &DevirtCalls, |
| SmallVectorImpl<CallInst *> &Assumes, const CallInst *CI, |
| DominatorTree &DT); |
| |
| /// Given a call to the intrinsic \@llvm.type.checked.load, find all |
| /// devirtualizable call sites based on the call and return them in DevirtCalls. |
| void findDevirtualizableCallsForTypeCheckedLoad( |
| SmallVectorImpl<DevirtCallSite> &DevirtCalls, |
| SmallVectorImpl<Instruction *> &LoadedPtrs, |
| SmallVectorImpl<Instruction *> &Preds, bool &HasNonCallUses, |
| const CallInst *CI, DominatorTree &DT); |
| |
| /// Processes a Constant recursively looking into elements of arrays, structs |
| /// and expressions to find a trivial pointer element that is located at the |
| /// given offset (relative to the beginning of the whole outer Constant). |
| /// |
| /// Used for example from GlobalDCE to find an entry in a C++ vtable that |
| /// matches a vcall offset. |
| /// |
| /// To support Swift vtables, getPointerAtOffset can see through "relative |
| /// pointers", i.e. (sub-)expressions of the form of: |
| /// |
| /// @symbol = ... { |
| /// i32 trunc (i64 sub ( |
| /// i64 ptrtoint (<type> @target to i64), i64 ptrtoint (... @symbol to i64) |
| /// ) to i32) |
| /// } |
| /// |
| /// For such (sub-)expressions, getPointerAtOffset returns the @target pointer. |
| Constant *getPointerAtOffset(Constant *I, uint64_t Offset, Module &M, |
| Constant *TopLevelGlobal = nullptr); |
| |
| /// Finds the same "relative pointer" pattern as described above, where the |
| /// target is `F`, and replaces the entire pattern with a constant zero. |
| void replaceRelativePointerUsersWithZero(Function *F); |
| |
| } // namespace llvm |
| |
| #endif |