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| 14 | pmbaty | 1 | //===--------- EHFrameSupport.h - JITLink eh-frame utils --------*- C++ -*-===// |
| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // |
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| 9 | // EHFrame registration support for JITLink. |
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| 10 | // |
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| 11 | //===----------------------------------------------------------------------===// |
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| 12 | |||
| 13 | #ifndef LLVM_EXECUTIONENGINE_JITLINK_EHFRAMESUPPORT_H |
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| 14 | #define LLVM_EXECUTIONENGINE_JITLINK_EHFRAMESUPPORT_H |
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| 15 | |||
| 16 | #include "llvm/ADT/Triple.h" |
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| 17 | #include "llvm/ExecutionEngine/JITLink/JITLink.h" |
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| 18 | #include "llvm/ExecutionEngine/JITSymbol.h" |
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| 19 | #include "llvm/Support/Error.h" |
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| 20 | |||
| 21 | namespace llvm { |
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| 22 | namespace jitlink { |
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| 23 | |||
| 24 | /// Inspect an eh-frame CFI record. |
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| 25 | class EHFrameCFIBlockInspector { |
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| 26 | public: |
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| 27 | /// Identify CFI record type and edges based on number and order of edges |
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| 28 | /// in the given block only. This assumes that the block contains one CFI |
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| 29 | /// record that has already been split out and fixed by the |
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| 30 | /// DWARFRecordSplitter and EHFrameEdgeFixer passes. |
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| 31 | /// |
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| 32 | /// Zero or one outgoing edges: Record is CIE. If present, edge points to |
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| 33 | /// personality. |
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| 34 | /// |
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| 35 | /// Two or three outgoing edges: Record is an FDE. First edge points to CIE, |
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| 36 | /// second to PC-begin, third (if present) to LSDA. |
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| 37 | /// |
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| 38 | /// It is illegal to call this function on a block with four or more edges. |
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| 39 | static EHFrameCFIBlockInspector FromEdgeScan(Block &B); |
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| 40 | |||
| 41 | /// Returns true if this frame is an FDE, false for a CIE. |
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| 42 | bool isFDE() const { return CIEEdge != nullptr; } |
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| 43 | |||
| 44 | /// Returns true if this frame is a CIE, false for an FDE. |
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| 45 | bool isCIE() const { return CIEEdge == nullptr; } |
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| 46 | |||
| 47 | /// If this is a CIE record, returns the Edge pointing at the personality |
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| 48 | /// function, if any. |
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| 49 | /// It is illegal to call this method on FDE records. |
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| 50 | Edge *getPersonalityEdge() const { |
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| 51 | assert(isCIE() && "CFI record is not a CIE"); |
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| 52 | return PersonalityEdge; |
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| 53 | } |
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| 54 | |||
| 55 | /// If this is an FDE record, returns the Edge pointing to the CIE. |
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| 56 | /// If this is a CIE record, returns null. |
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| 57 | /// |
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| 58 | /// The result is not valid if any modification has been made to the block |
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| 59 | /// after parsing. |
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| 60 | Edge *getCIEEdge() const { return CIEEdge; } |
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| 61 | |||
| 62 | /// If this is an FDE record, returns the Edge pointing at the PC-begin |
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| 63 | /// symbol. |
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| 64 | /// If this a CIE record, returns null. |
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| 65 | Edge *getPCBeginEdge() const { return PCBeginEdge; } |
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| 66 | |||
| 67 | /// If this is an FDE record, returns the Edge pointing at the LSDA, if any. |
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| 68 | /// It is illegal to call this method on CIE records. |
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| 69 | Edge *getLSDAEdge() const { |
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| 70 | assert(isFDE() && "CFI record is not an FDE"); |
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| 71 | return LSDAEdge; |
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| 72 | } |
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| 73 | |||
| 74 | private: |
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| 75 | EHFrameCFIBlockInspector(Edge *PersonalityEdge); |
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| 76 | EHFrameCFIBlockInspector(Edge &CIEEdge, Edge &PCBeginEdge, Edge *LSDAEdge); |
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| 77 | |||
| 78 | Edge *CIEEdge = nullptr; |
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| 79 | Edge *PCBeginEdge = nullptr; |
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| 80 | union { |
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| 81 | Edge *PersonalityEdge; |
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| 82 | Edge *LSDAEdge; |
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| 83 | }; |
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| 84 | }; |
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| 85 | |||
| 86 | /// Supports registration/deregistration of EH-frames in a target process. |
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| 87 | class EHFrameRegistrar { |
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| 88 | public: |
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| 89 | virtual ~EHFrameRegistrar(); |
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| 90 | virtual Error registerEHFrames(orc::ExecutorAddrRange EHFrameSection) = 0; |
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| 91 | virtual Error deregisterEHFrames(orc::ExecutorAddrRange EHFrameSection) = 0; |
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| 92 | }; |
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| 93 | |||
| 94 | /// Registers / Deregisters EH-frames in the current process. |
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| 95 | class InProcessEHFrameRegistrar final : public EHFrameRegistrar { |
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| 96 | public: |
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| 97 | Error registerEHFrames(orc::ExecutorAddrRange EHFrameSection) override; |
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| 98 | |||
| 99 | Error deregisterEHFrames(orc::ExecutorAddrRange EHFrameSection) override; |
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| 100 | }; |
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| 101 | |||
| 102 | using StoreFrameRangeFunction = std::function<void( |
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| 103 | orc::ExecutorAddr EHFrameSectionAddr, size_t EHFrameSectionSize)>; |
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| 104 | |||
| 105 | /// Creates a pass that records the address and size of the EH frame section. |
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| 106 | /// If no eh-frame section is found then the address and size will both be given |
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| 107 | /// as zero. |
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| 108 | /// |
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| 109 | /// Authors of JITLinkContexts can use this function to register a post-fixup |
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| 110 | /// pass that records the range of the eh-frame section. This range can |
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| 111 | /// be used after finalization to register and deregister the frame. |
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| 112 | LinkGraphPassFunction |
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| 113 | createEHFrameRecorderPass(const Triple &TT, |
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| 114 | StoreFrameRangeFunction StoreFrameRange); |
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| 115 | |||
| 116 | } // end namespace jitlink |
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| 117 | } // end namespace llvm |
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| 118 | |||
| 119 | #endif // LLVM_EXECUTIONENGINE_JITLINK_EHFRAMESUPPORT_H |