1//===------- EHFrameSupportImpl.h - JITLink eh-frame utils ------*- C++ -*-===//
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// EHFrame registration support for JITLink.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_LIB_EXECUTIONENGINE_JITLINK_EHFRAMESUPPORTIMPL_H
14#define LLVM_LIB_EXECUTIONENGINE_JITLINK_EHFRAMESUPPORTIMPL_H
15
16#include "llvm/ExecutionEngine/JITLink/EHFrameSupport.h"
17
18#include "llvm/ExecutionEngine/JITLink/JITLink.h"
19#include "llvm/Support/BinaryStreamReader.h"
20
21namespace llvm {
22namespace jitlink {
23
24/// A LinkGraph pass that adds missing FDE-to-CIE, FDE-to-PC and FDE-to-LSDA
25/// edges.
26class EHFrameEdgeFixer {
27public:
28 /// Create an eh-frame edge fixer.
29 /// If a given edge-kind is not supported on the target architecture then
30 /// Edge::Invalid should be used.
31 EHFrameEdgeFixer(StringRef EHFrameSectionName, unsigned PointerSize,
32 Edge::Kind Pointer32, Edge::Kind Pointer64,
33 Edge::Kind Delta32, Edge::Kind Delta64,
34 Edge::Kind NegDelta32);
35 Error operator()(LinkGraph &G);
36
37private:
38
39 struct AugmentationInfo {
40 bool AugmentationDataPresent = false;
41 bool EHDataFieldPresent = false;
42 uint8_t Fields[4] = {0x0, 0x0, 0x0, 0x0};
43 };
44
45 struct CIEInformation {
46 CIEInformation() = default;
47 CIEInformation(Symbol &CIESymbol) : CIESymbol(&CIESymbol) {}
48 Symbol *CIESymbol = nullptr;
49 bool AugmentationDataPresent = false;
50 bool LSDAPresent = false;
51 uint8_t LSDAEncoding = 0;
52 uint8_t AddressEncoding = 0;
53 };
54
55 struct EdgeTarget {
56 EdgeTarget() = default;
57 EdgeTarget(const Edge &E) : Target(&E.getTarget()), Addend(E.getAddend()) {}
58
59 Symbol *Target = nullptr;
60 Edge::AddendT Addend = 0;
61 };
62
63 struct BlockEdgesInfo {
64 DenseMap<Edge::OffsetT, EdgeTarget> TargetMap;
65 DenseSet<Edge::OffsetT> Multiple;
66 };
67
68 using CIEInfosMap = DenseMap<orc::ExecutorAddr, CIEInformation>;
69
70 struct ParseContext {
71 ParseContext(LinkGraph &G) : G(G) {}
72
73 Expected<CIEInformation *> findCIEInfo(orc::ExecutorAddr Address) {
74 auto I = CIEInfos.find(Val: Address);
75 if (I == CIEInfos.end())
76 return make_error<JITLinkError>(Args: "No CIE found at address " +
77 formatv(Fmt: "{0:x16}", Vals&: Address));
78 return &I->second;
79 }
80
81 LinkGraph &G;
82 CIEInfosMap CIEInfos;
83 BlockAddressMap AddrToBlock;
84 DenseMap<orc::ExecutorAddr, Symbol *> AddrToSym;
85 };
86
87 Error processBlock(ParseContext &PC, Block &B);
88 Error processCIE(ParseContext &PC, Block &B, size_t CIEDeltaFieldOffset,
89 const BlockEdgesInfo &BlockEdges);
90 Error processFDE(ParseContext &PC, Block &B, size_t CIEDeltaFieldOffset,
91 uint32_t CIEDelta, const BlockEdgesInfo &BlockEdges);
92
93 Expected<AugmentationInfo>
94 parseAugmentationString(BinaryStreamReader &RecordReader);
95
96 Expected<uint8_t> readPointerEncoding(BinaryStreamReader &RecordReader,
97 Block &InBlock, const char *FieldName);
98 Error skipEncodedPointer(uint8_t PointerEncoding,
99 BinaryStreamReader &RecordReader);
100 Expected<Symbol *> getOrCreateEncodedPointerEdge(
101 ParseContext &PC, const BlockEdgesInfo &BlockEdges,
102 uint8_t PointerEncoding, BinaryStreamReader &RecordReader,
103 Block &BlockToFix, size_t PointerFieldOffset, const char *FieldName);
104
105 Expected<Symbol &> getOrCreateSymbol(ParseContext &PC,
106 orc::ExecutorAddr Addr);
107
108 StringRef EHFrameSectionName;
109 unsigned PointerSize;
110 Edge::Kind Pointer32;
111 Edge::Kind Pointer64;
112 Edge::Kind Delta32;
113 Edge::Kind Delta64;
114 Edge::Kind NegDelta32;
115};
116
117/// Add a 32-bit null-terminator to the end of the eh-frame section.
118class EHFrameNullTerminator {
119public:
120 EHFrameNullTerminator(StringRef EHFrameSectionName);
121 Error operator()(LinkGraph &G);
122
123private:
124 static char NullTerminatorBlockContent[];
125 StringRef EHFrameSectionName;
126};
127
128} // end namespace jitlink
129} // end namespace llvm
130
131#endif // LLVM_LIB_EXECUTIONENGINE_JITLINK_EHFRAMESUPPORTIMPL_H
132