Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

Rev

Blame | Last modification | View Log | Download | RSS feed

  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/ADT/Triple.h"
  17. #include "llvm/ExecutionEngine/JITLink/JITLink.h"
  18. #include "llvm/ExecutionEngine/JITSymbol.h"
  19. #include "llvm/Support/Error.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.