bb1765179e
Replace "concept based polymorphism" with simpler PImpl idiom. This pursues two goals: * Enforce static type checking. Previously, target implementations hid base class methods and type checking was impossible. Now that they override the methods, the compiler will complain on mismatched signatures. * Make the code easier to navigate. Previously, if you asked your favorite LSP server to show a method (e.g. `getInstructionCost()`), it would show you methods from `TTI`, `TTI::Concept`, `TTI::Model`, `TTIImplBase`, and target overrides. Now it is two less :) There are three commits to hopefully simplify the review. The first commit removes `TTI::Model`. This is done by deriving `TargetTransformInfoImplBase` from `TTI::Concept`. This is possible because they implement the same set of interfaces with identical signatures. The first commit makes `TargetTransformImplBase` polymorphic, which means all derived classes should `override` its methods. This is done in second commit to make the first one smaller. It appeared infeasible to extract this into a separate PR because the first commit landed separately would result in tons of `-Woverloaded-virtual` warnings (and break `-Werror` builds). The third commit eliminates `TTI::Concept` by merging it with the only derived class `TargetTransformImplBase`. This commit could be extracted into a separate PR, but it touches the same lines in `TargetTransformInfoImpl.h` (removes `override` added by the second commit and adds `virtual`), so I thought it may make sense to land these two commits together. Pull Request: https://github.com/llvm/llvm-project/pull/136674
56 lines
2.1 KiB
C++
56 lines
2.1 KiB
C++
//===- SPIRVTargetTransformInfo.h - SPIR-V specific TTI ---------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// \file
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// This file contains a TargetTransformInfoImplBase conforming object specific
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// to the SPIRV target machine. It uses the target's detailed information to
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// provide more precise answers to certain TTI queries, while letting the
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// target independent and default TTI implementations handle the rest.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_TARGET_SPIRV_SPIRVTARGETTRANSFORMINFO_H
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#define LLVM_LIB_TARGET_SPIRV_SPIRVTARGETTRANSFORMINFO_H
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#include "SPIRV.h"
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#include "SPIRVTargetMachine.h"
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#include "llvm/Analysis/TargetTransformInfo.h"
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#include "llvm/CodeGen/BasicTTIImpl.h"
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namespace llvm {
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class SPIRVTTIImpl : public BasicTTIImplBase<SPIRVTTIImpl> {
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using BaseT = BasicTTIImplBase<SPIRVTTIImpl>;
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using TTI = TargetTransformInfo;
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friend BaseT;
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const SPIRVSubtarget *ST;
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const SPIRVTargetLowering *TLI;
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const TargetSubtargetInfo *getST() const { return ST; }
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const SPIRVTargetLowering *getTLI() const { return TLI; }
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public:
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explicit SPIRVTTIImpl(const SPIRVTargetMachine *TM, const Function &F)
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: BaseT(TM, F.getDataLayout()), ST(TM->getSubtargetImpl(F)),
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TLI(ST->getTargetLowering()) {}
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TTI::PopcntSupportKind getPopcntSupport(unsigned TyWidth) const override {
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// SPIR-V natively supports OpBitcount, per 3.53.14 in the spec, as such it
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// is reasonable to assume the Op is fast / preferable to the expanded loop.
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// Furthermore, this prevents information being lost if transforms are
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// applied to SPIR-V before lowering to a concrete target.
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if (!isPowerOf2_32(TyWidth) || TyWidth > 64)
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return TTI::PSK_Software; // Arbitrary bit-width INT is not core SPIR-V.
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return TTI::PSK_FastHardware;
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}
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};
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} // namespace llvm
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#endif // LLVM_LIB_TARGET_SPIRV_SPIRVTARGETTRANSFORMINFO_H
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