1 | //===--------- EHFrameSupport.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_EXECUTIONENGINE_JITLINK_EHFRAMESUPPORT_H |
14 | #define LLVM_EXECUTIONENGINE_JITLINK_EHFRAMESUPPORT_H |
15 | |
16 | #include "llvm/ExecutionEngine/JITLink/JITLink.h" |
17 | #include "llvm/ExecutionEngine/JITSymbol.h" |
18 | #include "llvm/Support/Error.h" |
19 | #include "llvm/TargetParser/Triple.h" |
20 | |
21 | namespace llvm { |
22 | namespace jitlink { |
23 | |
24 | /// Inspect an eh-frame CFI record. |
25 | class EHFrameCFIBlockInspector { |
26 | public: |
27 | /// Identify CFI record type and edges based on number and order of edges |
28 | /// in the given block only. This assumes that the block contains one CFI |
29 | /// record that has already been split out and fixed by the |
30 | /// DWARFRecordSplitter and EHFrameEdgeFixer passes. |
31 | /// |
32 | /// Zero or one outgoing edges: Record is CIE. If present, edge points to |
33 | /// personality. |
34 | /// |
35 | /// Two or three outgoing edges: Record is an FDE. First edge points to CIE, |
36 | /// second to PC-begin, third (if present) to LSDA. |
37 | /// |
38 | /// It is illegal to call this function on a block with four or more edges. |
39 | static EHFrameCFIBlockInspector FromEdgeScan(Block &B); |
40 | |
41 | /// Returns true if this frame is an FDE, false for a CIE. |
42 | bool isFDE() const { return CIEEdge != nullptr; } |
43 | |
44 | /// Returns true if this frame is a CIE, false for an FDE. |
45 | bool isCIE() const { return CIEEdge == nullptr; } |
46 | |
47 | /// If this is a CIE record, returns the Edge pointing at the personality |
48 | /// function, if any. |
49 | /// It is illegal to call this method on FDE records. |
50 | Edge *getPersonalityEdge() const { |
51 | assert(isCIE() && "CFI record is not a CIE" ); |
52 | return PersonalityEdge; |
53 | } |
54 | |
55 | /// If this is an FDE record, returns the Edge pointing to the CIE. |
56 | /// If this is a CIE record, returns null. |
57 | /// |
58 | /// The result is not valid if any modification has been made to the block |
59 | /// after parsing. |
60 | Edge *getCIEEdge() const { return CIEEdge; } |
61 | |
62 | /// If this is an FDE record, returns the Edge pointing at the PC-begin |
63 | /// symbol. |
64 | /// If this a CIE record, returns null. |
65 | Edge *getPCBeginEdge() const { return PCBeginEdge; } |
66 | |
67 | /// If this is an FDE record, returns the Edge pointing at the LSDA, if any. |
68 | /// It is illegal to call this method on CIE records. |
69 | Edge *getLSDAEdge() const { |
70 | assert(isFDE() && "CFI record is not an FDE" ); |
71 | return LSDAEdge; |
72 | } |
73 | |
74 | private: |
75 | EHFrameCFIBlockInspector(Edge *PersonalityEdge); |
76 | EHFrameCFIBlockInspector(Edge &CIEEdge, Edge &PCBeginEdge, Edge *LSDAEdge); |
77 | |
78 | Edge *CIEEdge = nullptr; |
79 | Edge *PCBeginEdge = nullptr; |
80 | union { |
81 | Edge *PersonalityEdge; |
82 | Edge *LSDAEdge; |
83 | }; |
84 | }; |
85 | |
86 | /// Supports registration/deregistration of EH-frames in a target process. |
87 | class EHFrameRegistrar { |
88 | public: |
89 | virtual ~EHFrameRegistrar(); |
90 | virtual Error registerEHFrames(orc::ExecutorAddrRange EHFrameSection) = 0; |
91 | virtual Error deregisterEHFrames(orc::ExecutorAddrRange EHFrameSection) = 0; |
92 | }; |
93 | |
94 | /// Registers / Deregisters EH-frames in the current process. |
95 | class InProcessEHFrameRegistrar final : public EHFrameRegistrar { |
96 | public: |
97 | Error registerEHFrames(orc::ExecutorAddrRange EHFrameSection) override; |
98 | |
99 | Error deregisterEHFrames(orc::ExecutorAddrRange EHFrameSection) override; |
100 | }; |
101 | |
102 | using StoreFrameRangeFunction = std::function<void( |
103 | orc::ExecutorAddr EHFrameSectionAddr, size_t EHFrameSectionSize)>; |
104 | |
105 | /// Creates a pass that records the address and size of the EH frame section. |
106 | /// If no eh-frame section is found then the address and size will both be given |
107 | /// as zero. |
108 | /// |
109 | /// Authors of JITLinkContexts can use this function to register a post-fixup |
110 | /// pass that records the range of the eh-frame section. This range can |
111 | /// be used after finalization to register and deregister the frame. |
112 | LinkGraphPassFunction |
113 | createEHFrameRecorderPass(const Triple &TT, |
114 | StoreFrameRangeFunction StoreFrameRange); |
115 | |
116 | } // end namespace jitlink |
117 | } // end namespace llvm |
118 | |
119 | #endif // LLVM_EXECUTIONENGINE_JITLINK_EHFRAMESUPPORT_H |
120 | |