1 //===-- TBAABuilder.cpp -- TBAA builder definitions -----------------------===// 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 // Coding style: https://mlir.llvm.org/getting_started/DeveloperGuide/ 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "flang/Optimizer/CodeGen/TBAABuilder.h" 14 #include "flang/Optimizer/Dialect/FIRType.h" 15 #include "llvm/ADT/TypeSwitch.h" 16 #include "llvm/Support/CommandLine.h" 17 #include "llvm/Support/Debug.h" 18 19 #define DEBUG_TYPE "flang-tbaa-builder" 20 21 using namespace mlir; 22 using namespace mlir::LLVM; 23 24 static llvm::cl::opt<bool> disableTBAA( 25 "disable-tbaa", 26 llvm::cl::desc("disable attaching TBAA tags to memory accessing operations " 27 "to override default Flang behavior"), 28 llvm::cl::init(false)); 29 30 // tagAttachmentLimit is a debugging option that allows limiting 31 // the number of TBAA access tag attributes attached to operations. 32 // It is set to kTagAttachmentUnlimited by default denoting "no limit". 33 static constexpr unsigned kTagAttachmentUnlimited = 34 std::numeric_limits<unsigned>::max(); 35 static llvm::cl::opt<unsigned> 36 tagAttachmentLimit("tbaa-attach-tag-max", llvm::cl::desc(""), 37 llvm::cl::init(kTagAttachmentUnlimited)); 38 39 namespace fir { 40 41 TBAABuilder::TBAABuilder(MLIRContext *context, bool applyTBAA) 42 : enableTBAA(applyTBAA && !disableTBAA) { 43 if (!enableTBAA) 44 return; 45 46 // Root node. 47 flangTBAARoot = 48 TBAARootAttr::get(context, StringAttr::get(context, flangTBAARootId)); 49 50 // Any access node. 51 anyAccessTypeDesc = TBAATypeDescriptorAttr::get( 52 context, anyAccessTypeDescId, TBAAMemberAttr::get(flangTBAARoot, 0)); 53 54 // Any data access node. 55 anyDataAccessTypeDesc = 56 TBAATypeDescriptorAttr::get(context, anyDataAccessTypeDescId, 57 TBAAMemberAttr::get(anyAccessTypeDesc, 0)); 58 59 // Box member access node. 60 boxMemberTypeDesc = TBAATypeDescriptorAttr::get( 61 context, boxMemberTypeDescId, TBAAMemberAttr::get(anyAccessTypeDesc, 0)); 62 } 63 64 TBAATagAttr TBAABuilder::getAccessTag(TBAATypeDescriptorAttr baseTypeDesc, 65 TBAATypeDescriptorAttr accessTypeDesc, 66 int64_t offset) { 67 TBAATagAttr &tag = tagsMap[{baseTypeDesc, accessTypeDesc, offset}]; 68 if (tag) 69 return tag; 70 71 // Initialize new tag. 72 tag = TBAATagAttr::get(baseTypeDesc, accessTypeDesc, offset); 73 return tag; 74 } 75 76 TBAATagAttr TBAABuilder::getAnyBoxAccessTag() { 77 return getAccessTag(boxMemberTypeDesc, boxMemberTypeDesc, /*offset=*/0); 78 } 79 80 TBAATagAttr TBAABuilder::getBoxAccessTag(Type baseFIRType, Type accessFIRType, 81 GEPOp gep) { 82 return getAnyBoxAccessTag(); 83 } 84 85 TBAATagAttr TBAABuilder::getAnyDataAccessTag() { 86 return getAccessTag(anyDataAccessTypeDesc, anyDataAccessTypeDesc, 87 /*offset=*/0); 88 } 89 90 TBAATagAttr TBAABuilder::getDataAccessTag(Type baseFIRType, Type accessFIRType, 91 GEPOp gep) { 92 return getAnyDataAccessTag(); 93 } 94 95 TBAATagAttr TBAABuilder::getAnyAccessTag() { 96 return getAccessTag(anyAccessTypeDesc, anyAccessTypeDesc, /*offset=*/0); 97 } 98 99 void TBAABuilder::attachTBAATag(AliasAnalysisOpInterface op, Type baseFIRType, 100 Type accessFIRType, GEPOp gep) { 101 if (!enableTBAA) 102 return; 103 104 ++tagAttachmentCounter; 105 if (tagAttachmentLimit != kTagAttachmentUnlimited && 106 tagAttachmentCounter > tagAttachmentLimit) 107 return; 108 109 LLVM_DEBUG(llvm::dbgs() << "Attaching TBAA tag #" << tagAttachmentCounter 110 << "\n"); 111 112 TBAATagAttr tbaaTagSym; 113 if (fir::isRecordWithDescriptorMember(baseFIRType)) { 114 // A memory access that addresses an aggregate that contains 115 // a mix of data members and descriptor members may alias 116 // with both data and descriptor accesses. 117 // Conservatively set any-access tag if there is any descriptor member. 118 tbaaTagSym = getAnyAccessTag(); 119 } else if (baseFIRType.isa<fir::BaseBoxType>()) { 120 tbaaTagSym = getBoxAccessTag(baseFIRType, accessFIRType, gep); 121 } else { 122 tbaaTagSym = getDataAccessTag(baseFIRType, accessFIRType, gep); 123 } 124 125 if (!tbaaTagSym) 126 return; 127 128 op.setTBAATags(ArrayAttr::get(op->getContext(), tbaaTagSym)); 129 } 130 131 } // namespace fir 132