llvm/lib/ExecutionEngine/JITLink/EHFrameSupportImpl.h

   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
  21 namespace llvm {
  22 namespace jitlink {
  23
  24 /// A LinkGraph pass that adds missing FDE-to-CIE, FDE-to-PC and FDE-to-LSDA
  25 /// edges.
  26 class EHFrameEdgeFixer {
  27 public:
  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
  37 private:
  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(Address);
  75       if (I == CIEInfos.end())
  76         return make_error<JITLinkError>("No CIE found at address " +
  77                                         formatv("{0:x16}", 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.
 118 class EHFrameNullTerminator {
 119 public:
 120   EHFrameNullTerminator(StringRef EHFrameSectionName);
 121   Error operator()(LinkGraph &G);
 122
 123 private:
 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