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
19using namespace llvm;
20
21#define DEBUG_TYPE "faultmaps"
22
23static const int FaultMapVersion = 1;
24const char *FaultMaps::WFMP = "Fault Maps: ";
25
26FaultMaps::FaultMaps(AsmPrinter &AP) : AP(AP) {}
27
28void 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 LHS: MCSymbolRefExpr::create(Symbol: FaultingLabel, Ctx&: OutContext),
35 RHS: MCSymbolRefExpr::create(Symbol: AP.CurrentFnSymForSize, Ctx&: OutContext), Ctx&: OutContext);
36
37 const MCExpr *HandlerOffset = MCBinaryExpr::createSub(
38 LHS: MCSymbolRefExpr::create(Symbol: HandlerLabel, Ctx&: OutContext),
39 RHS: MCSymbolRefExpr::create(Symbol: AP.CurrentFnSymForSize, Ctx&: OutContext), Ctx&: OutContext);
40
41 FunctionInfos[AP.CurrentFnSym].emplace_back(args&: FaultTy, args&: FaultingOffset,
42 args&: HandlerOffset);
43}
44
45void 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(Section: FaultMapSection);
56
57 // Emit a dummy symbol to force section inclusion.
58 OS.emitLabel(Symbol: OutContext.getOrCreateSymbol(Name: Twine("__LLVM_FaultMaps")));
59
60 LLVM_DEBUG(dbgs() << "********** Fault Map Output **********\n");
61
62 // Header
63 OS.emitIntValue(Value: FaultMapVersion, Size: 1); // Version.
64 OS.emitIntValue(Value: 0, Size: 1); // Reserved.
65 OS.emitInt16(Value: 0); // Reserved.
66
67 LLVM_DEBUG(dbgs() << WFMP << "#functions = " << FunctionInfos.size() << "\n");
68 OS.emitInt32(Value: FunctionInfos.size());
69
70 LLVM_DEBUG(dbgs() << WFMP << "functions:\n");
71
72 for (const auto &FFI : FunctionInfos)
73 emitFunctionInfo(FnLabel: FFI.first, FFI: FFI.second);
74}
75
76void 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(Sym: FnLabel, Size: 8);
82
83 LLVM_DEBUG(dbgs() << WFMP << " #faulting PCs: " << FFI.size() << "\n");
84 OS.emitInt32(Value: FFI.size());
85
86 OS.emitInt32(Value: 0); // Reserved
87
88 for (const auto &Fault : FFI) {
89 OS.emitInt32(Value: Fault.Kind);
90 OS.emitValue(Value: Fault.FaultingOffsetExpr, Size: 4);
91 OS.emitValue(Value: Fault.HandlerOffsetExpr, Size: 4);
92 }
93}
94
95const char *FaultMaps::faultTypeToString(FaultMaps::FaultKind FT) {
96 switch (FT) {
97 default:
98 llvm_unreachable("unhandled fault type!");
99 case FaultMaps::FaultingLoad:
100 return "FaultingLoad";
101 case FaultMaps::FaultingLoadStore:
102 return "FaultingLoadStore";
103 case FaultMaps::FaultingStore:
104 return "FaultingStore";
105 }
106}
107