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      1 //===-- ARMUnwindOpAsm.h - ARM Unwind Opcodes Assembler ---------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file declares the unwind opcode assmebler for ARM exception handling
     11 // table.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #ifndef LLVM_LIB_TARGET_ARM_MCTARGETDESC_ARMUNWINDOPASM_H
     16 #define LLVM_LIB_TARGET_ARM_MCTARGETDESC_ARMUNWINDOPASM_H
     17 
     18 #include "llvm/ADT/SmallVector.h"
     19 #include "llvm/Support/ARMEHABI.h"
     20 #include "llvm/Support/DataTypes.h"
     21 
     22 namespace llvm {
     23 
     24 class MCSymbol;
     25 
     26 class UnwindOpcodeAssembler {
     27 private:
     28   llvm::SmallVector<uint8_t, 32> Ops;
     29   llvm::SmallVector<unsigned, 8> OpBegins;
     30   bool HasPersonality;
     31 
     32 public:
     33   UnwindOpcodeAssembler()
     34       : HasPersonality(0) {
     35     OpBegins.push_back(0);
     36   }
     37 
     38   /// Reset the unwind opcode assembler.
     39   void Reset() {
     40     Ops.clear();
     41     OpBegins.clear();
     42     OpBegins.push_back(0);
     43     HasPersonality = 0;
     44   }
     45 
     46   /// Set the personality
     47   void setPersonality(const MCSymbol *Per) {
     48     HasPersonality = 1;
     49   }
     50 
     51   /// Emit unwind opcodes for .save directives
     52   void EmitRegSave(uint32_t RegSave);
     53 
     54   /// Emit unwind opcodes for .vsave directives
     55   void EmitVFPRegSave(uint32_t VFPRegSave);
     56 
     57   /// Emit unwind opcodes to copy address from source register to $sp.
     58   void EmitSetSP(uint16_t Reg);
     59 
     60   /// Emit unwind opcodes to add $sp with an offset.
     61   void EmitSPOffset(int64_t Offset);
     62 
     63   /// Emit unwind raw opcodes
     64   void EmitRaw(const SmallVectorImpl<uint8_t> &Opcodes) {
     65     Ops.insert(Ops.end(), Opcodes.begin(), Opcodes.end());
     66     OpBegins.push_back(OpBegins.back() + Opcodes.size());
     67   }
     68 
     69   /// Finalize the unwind opcode sequence for EmitBytes()
     70   void Finalize(unsigned &PersonalityIndex,
     71                 SmallVectorImpl<uint8_t> &Result);
     72 
     73 private:
     74   void EmitInt8(unsigned Opcode) {
     75     Ops.push_back(Opcode & 0xff);
     76     OpBegins.push_back(OpBegins.back() + 1);
     77   }
     78 
     79   void EmitInt16(unsigned Opcode) {
     80     Ops.push_back((Opcode >> 8) & 0xff);
     81     Ops.push_back(Opcode & 0xff);
     82     OpBegins.push_back(OpBegins.back() + 2);
     83   }
     84 
     85   void EmitBytes(const uint8_t *Opcode, size_t Size) {
     86     Ops.insert(Ops.end(), Opcode, Opcode + Size);
     87     OpBegins.push_back(OpBegins.back() + Size);
     88   }
     89 };
     90 
     91 } // namespace llvm
     92 
     93 #endif
     94