1 //===- CBuffer.cpp - HLSL constant buffer handling ------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "llvm/Frontend/HLSL/CBuffer.h" 10 #include "llvm/Frontend/HLSL/HLSLResource.h" 11 #include "llvm/IR/DerivedTypes.h" 12 #include "llvm/IR/Metadata.h" 13 #include "llvm/IR/Module.h" 14 15 using namespace llvm; 16 using namespace llvm::hlsl; 17 18 static size_t getMemberOffset(GlobalVariable *Handle, size_t Index) { 19 auto *HandleTy = cast<TargetExtType>(Handle->getValueType()); 20 assert(HandleTy->getName().ends_with(".CBuffer") && "Not a cbuffer type"); 21 assert(HandleTy->getNumTypeParameters() == 1 && "Expected layout type"); 22 23 auto *LayoutTy = cast<TargetExtType>(HandleTy->getTypeParameter(0)); 24 assert(LayoutTy->getName().ends_with(".Layout") && "Not a layout type"); 25 26 // Skip the "size" parameter. 27 size_t ParamIndex = Index + 1; 28 assert(LayoutTy->getNumIntParameters() > ParamIndex && 29 "Not enough parameters"); 30 31 return LayoutTy->getIntParameter(ParamIndex); 32 } 33 34 std::optional<CBufferMetadata> CBufferMetadata::get(Module &M) { 35 NamedMDNode *CBufMD = M.getNamedMetadata("hlsl.cbs"); 36 if (!CBufMD) 37 return std::nullopt; 38 39 std::optional<CBufferMetadata> Result({CBufMD}); 40 41 for (const MDNode *MD : CBufMD->operands()) { 42 assert(MD->getNumOperands() && "Invalid cbuffer metadata"); 43 44 auto *Handle = cast<GlobalVariable>( 45 cast<ValueAsMetadata>(MD->getOperand(0))->getValue()); 46 CBufferMapping &Mapping = Result->Mappings.emplace_back(Handle); 47 48 for (int I = 1, E = MD->getNumOperands(); I < E; ++I) { 49 Metadata *OpMD = MD->getOperand(I); 50 // Some members may be null if they've been optimized out. 51 if (!OpMD) 52 continue; 53 auto *V = cast<GlobalVariable>(cast<ValueAsMetadata>(OpMD)->getValue()); 54 Mapping.Members.emplace_back(V, getMemberOffset(Handle, I - 1)); 55 } 56 } 57 58 return Result; 59 } 60 61 void CBufferMetadata::eraseFromModule() { 62 // Remove the cbs named metadata 63 MD->eraseFromParent(); 64 } 65 66 APInt hlsl::translateCBufArrayOffset(const DataLayout &DL, APInt Offset, 67 ArrayType *Ty) { 68 int64_t TypeSize = DL.getTypeSizeInBits(Ty->getElementType()) / 8; 69 int64_t RoundUp = alignTo(TypeSize, Align(CBufferRowSizeInBytes)); 70 return Offset.udiv(TypeSize) * RoundUp; 71 } 72