1 //===- FaultMaps.cpp ------------------------------------------------------===// 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/CodeGen/FaultMaps.h" 10 #include "llvm/ADT/Twine.h" 11 #include "llvm/CodeGen/AsmPrinter.h" 12 #include "llvm/MC/MCContext.h" 13 #include "llvm/MC/MCExpr.h" 14 #include "llvm/MC/MCObjectFileInfo.h" 15 #include "llvm/MC/MCStreamer.h" 16 #include "llvm/Support/Debug.h" 17 #include "llvm/Support/ErrorHandling.h" 18 19 using namespace llvm; 20 21 #define DEBUG_TYPE "faultmaps" 22 23 static const int FaultMapVersion = 1; 24 const char *FaultMaps::WFMP = "Fault Maps: "; 25 26 FaultMaps::FaultMaps(AsmPrinter &AP) : AP(AP) {} 27 28 void FaultMaps::recordFaultingOp(FaultKind FaultTy, 29 const MCSymbol *FaultingLabel, 30 const MCSymbol *HandlerLabel) { 31 MCContext &OutContext = AP.OutStreamer->getContext(); 32 33 const MCExpr *FaultingOffset = MCBinaryExpr::createSub( 34 MCSymbolRefExpr::create(FaultingLabel, OutContext), 35 MCSymbolRefExpr::create(AP.CurrentFnSymForSize, OutContext), OutContext); 36 37 const MCExpr *HandlerOffset = MCBinaryExpr::createSub( 38 MCSymbolRefExpr::create(HandlerLabel, OutContext), 39 MCSymbolRefExpr::create(AP.CurrentFnSymForSize, OutContext), OutContext); 40 41 FunctionInfos[AP.CurrentFnSym].emplace_back(FaultTy, FaultingOffset, 42 HandlerOffset); 43 } 44 45 void FaultMaps::serializeToFaultMapSection() { 46 if (FunctionInfos.empty()) 47 return; 48 49 MCContext &OutContext = AP.OutStreamer->getContext(); 50 MCStreamer &OS = *AP.OutStreamer; 51 52 // Create the section. 53 MCSection *FaultMapSection = 54 OutContext.getObjectFileInfo()->getFaultMapSection(); 55 OS.switchSection(FaultMapSection); 56 57 // Emit a dummy symbol to force section inclusion. 58 OS.emitLabel(OutContext.getOrCreateSymbol(Twine("__LLVM_FaultMaps"))); 59 60 LLVM_DEBUG(dbgs() << "********** Fault Map Output **********\n"); 61 62 // Header 63 OS.emitIntValue(FaultMapVersion, 1); // Version. 64 OS.emitIntValue(0, 1); // Reserved. 65 OS.emitInt16(0); // Reserved. 66 67 LLVM_DEBUG(dbgs() << WFMP << "#functions = " << FunctionInfos.size() << "\n"); 68 OS.emitInt32(FunctionInfos.size()); 69 70 LLVM_DEBUG(dbgs() << WFMP << "functions:\n"); 71 72 for (const auto &FFI : FunctionInfos) 73 emitFunctionInfo(FFI.first, FFI.second); 74 } 75 76 void FaultMaps::emitFunctionInfo(const MCSymbol *FnLabel, 77 const FunctionFaultInfos &FFI) { 78 MCStreamer &OS = *AP.OutStreamer; 79 80 LLVM_DEBUG(dbgs() << WFMP << " function addr: " << *FnLabel << "\n"); 81 OS.emitSymbolValue(FnLabel, 8); 82 83 LLVM_DEBUG(dbgs() << WFMP << " #faulting PCs: " << FFI.size() << "\n"); 84 OS.emitInt32(FFI.size()); 85 86 OS.emitInt32(0); // Reserved 87 88 for (const auto &Fault : FFI) { 89 LLVM_DEBUG(dbgs() << WFMP << " fault type: " 90 << faultTypeToString(Fault.Kind) << "\n"); 91 OS.emitInt32(Fault.Kind); 92 93 LLVM_DEBUG(dbgs() << WFMP << " faulting PC offset: " 94 << *Fault.FaultingOffsetExpr << "\n"); 95 OS.emitValue(Fault.FaultingOffsetExpr, 4); 96 97 LLVM_DEBUG(dbgs() << WFMP << " fault handler PC offset: " 98 << *Fault.HandlerOffsetExpr << "\n"); 99 OS.emitValue(Fault.HandlerOffsetExpr, 4); 100 } 101 } 102 103 const char *FaultMaps::faultTypeToString(FaultMaps::FaultKind FT) { 104 switch (FT) { 105 default: 106 llvm_unreachable("unhandled fault type!"); 107 case FaultMaps::FaultingLoad: 108 return "FaultingLoad"; 109 case FaultMaps::FaultingLoadStore: 110 return "FaultingLoadStore"; 111 case FaultMaps::FaultingStore: 112 return "FaultingStore"; 113 } 114 } 115