lib/Target/AArch64/Disassembler/AArch64ExternalSymbolizer.cpp

   1 //===- AArch64ExternalSymbolizer.cpp - Symbolizer for AArch64 ---*- 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 #include "AArch64ExternalSymbolizer.h"
  10 #include "MCTargetDesc/AArch64AddressingModes.h"
  11 #include "Utils/AArch64BaseInfo.h"
  12 #include "llvm/MC/MCContext.h"
  13 #include "llvm/MC/MCExpr.h"
  14 #include "llvm/MC/MCInst.h"
  15 #include "llvm/MC/MCRegisterInfo.h"
  16 #include "llvm/Support/Format.h"
  17 #include "llvm/Support/raw_ostream.h"
  18
  19 using namespace llvm;
  20
  21 #define DEBUG_TYPE "aarch64-disassembler"
  22
  23 static MCSymbolRefExpr::VariantKind
  24 getVariant(uint64_t LLVMDisassembler_VariantKind) {
  25   switch (LLVMDisassembler_VariantKind) {
  26   case LLVMDisassembler_VariantKind_None:
  27     return MCSymbolRefExpr::VK_None;
  28   case LLVMDisassembler_VariantKind_ARM64_PAGE:
  29     return MCSymbolRefExpr::VK_PAGE;
  30   case LLVMDisassembler_VariantKind_ARM64_PAGEOFF:
  31     return MCSymbolRefExpr::VK_PAGEOFF;
  32   case LLVMDisassembler_VariantKind_ARM64_GOTPAGE:
  33     return MCSymbolRefExpr::VK_GOTPAGE;
  34   case LLVMDisassembler_VariantKind_ARM64_GOTPAGEOFF:
  35     return MCSymbolRefExpr::VK_GOTPAGEOFF;
  36   case LLVMDisassembler_VariantKind_ARM64_TLVP:
  37   case LLVMDisassembler_VariantKind_ARM64_TLVOFF:
  38   default:
  39     llvm_unreachable("bad LLVMDisassembler_VariantKind");
  40   }
  41 }
  42
  43 /// tryAddingSymbolicOperand - tryAddingSymbolicOperand trys to add a symbolic
  44 /// operand in place of the immediate Value in the MCInst.  The immediate
  45 /// Value has not had any PC adjustment made by the caller. If the instruction
  46 /// is a branch that adds the PC to the immediate Value then isBranch is
  47 /// Success, else Fail. If GetOpInfo is non-null, then it is called to get any
  48 /// symbolic information at the Address for this instrution.  If that returns
  49 /// non-zero then the symbolic information it returns is used to create an
  50 /// MCExpr and that is added as an operand to the MCInst.  If GetOpInfo()
  51 /// returns zero and isBranch is Success then a symbol look up for
  52 /// Address + Value is done and if a symbol is found an MCExpr is created with
  53 /// that, else an MCExpr with Address + Value is created.  If GetOpInfo()
  54 /// returns zero and isBranch is Fail then the Opcode of the MCInst is
  55 /// tested and for ADRP an other instructions that help to load of pointers
  56 /// a symbol look up is done to see it is returns a specific reference type
  57 /// to add to the comment stream.  This function returns Success if it adds
  58 /// an operand to the MCInst and Fail otherwise.
  59 bool AArch64ExternalSymbolizer::tryAddingSymbolicOperand(
  60     MCInst &MI, raw_ostream &CommentStream, int64_t Value, uint64_t Address,
  61     bool IsBranch, uint64_t Offset, uint64_t InstSize) {
  62   if (!SymbolLookUp)
  63     return false;
  64   // FIXME: This method shares a lot of code with
  65   //        MCExternalSymbolizer::tryAddingSymbolicOperand. It may be possible
  66   //        refactor the MCExternalSymbolizer interface to allow more of this
  67   //        implementation to be shared.
  68   //
  69   struct LLVMOpInfo1 SymbolicOp;
  70   memset(&SymbolicOp, '\0', sizeof(struct LLVMOpInfo1));
  71   SymbolicOp.Value = Value;
  72   uint64_t ReferenceType;
  73   const char *ReferenceName;
  74   if (!GetOpInfo ||
  75       !GetOpInfo(DisInfo, Address, 0 /* Offset */, InstSize, 1, &SymbolicOp)) {
  76     if (IsBranch) {
  77       ReferenceType = LLVMDisassembler_ReferenceType_In_Branch;
  78       const char *Name = SymbolLookUp(DisInfo, Address + Value, &ReferenceType,
  79                                       Address, &ReferenceName);
  80       if (Name) {
  81         SymbolicOp.AddSymbol.Name = Name;
  82         SymbolicOp.AddSymbol.Present = true;
  83         SymbolicOp.Value = 0;
  84       } else {
  85         SymbolicOp.Value = Address + Value;
  86       }
  87       if (ReferenceType == LLVMDisassembler_ReferenceType_Out_SymbolStub)
  88         CommentStream << "symbol stub for: " << ReferenceName;
  89       else if (ReferenceType ==
  90                LLVMDisassembler_ReferenceType_Out_Objc_Message)
  91         CommentStream << "Objc message: " << ReferenceName;
  92     } else if (MI.getOpcode() == AArch64::ADRP) {
  93         ReferenceType = LLVMDisassembler_ReferenceType_In_ARM64_ADRP;
  94         // otool expects the fully encoded ADRP instruction to be passed in as
  95         // the value here, so reconstruct it:
  96         const MCRegisterInfo &MCRI = *Ctx.getRegisterInfo();
  97         uint32_t EncodedInst = 0x90000000;
  98         EncodedInst |= (Value & 0x3) << 29; // immlo
  99         EncodedInst |= ((Value >> 2) & 0x7FFFF) << 5; // immhi
 100         EncodedInst |= MCRI.getEncodingValue(MI.getOperand(0).getReg()); // reg
 101         SymbolLookUp(DisInfo, EncodedInst, &ReferenceType, Address,
 102                      &ReferenceName);
 103         CommentStream << format("0x%llx", (0xfffffffffffff000LL & Address) +
 104                                               Value * 0x1000);
 105     } else if (MI.getOpcode() == AArch64::ADDXri ||
 106                MI.getOpcode() == AArch64::LDRXui ||
 107                MI.getOpcode() == AArch64::LDRXl ||
 108                MI.getOpcode() == AArch64::ADR) {
 109       if (MI.getOpcode() == AArch64::ADDXri)
 110         ReferenceType = LLVMDisassembler_ReferenceType_In_ARM64_ADDXri;
 111       else if (MI.getOpcode() == AArch64::LDRXui)
 112         ReferenceType = LLVMDisassembler_ReferenceType_In_ARM64_LDRXui;
 113       if (MI.getOpcode() == AArch64::LDRXl) {
 114         ReferenceType = LLVMDisassembler_ReferenceType_In_ARM64_LDRXl;
 115         SymbolLookUp(DisInfo, Address + Value, &ReferenceType, Address,
 116                      &ReferenceName);
 117       } else if (MI.getOpcode() == AArch64::ADR) {
 118         ReferenceType = LLVMDisassembler_ReferenceType_In_ARM64_ADR;
 119         SymbolLookUp(DisInfo, Address + Value, &ReferenceType, Address,
 120                             &ReferenceName);
 121       } else {
 122         const MCRegisterInfo &MCRI = *Ctx.getRegisterInfo();
 123         // otool expects the fully encoded ADD/LDR instruction to be passed in
 124         // as the value here, so reconstruct it:
 125         unsigned EncodedInst =
 126           MI.getOpcode() == AArch64::ADDXri ? 0x91000000: 0xF9400000;
 127         EncodedInst |= Value << 10; // imm12 [+ shift:2 for ADD]
 128         EncodedInst |=
 129           MCRI.getEncodingValue(MI.getOperand(1).getReg()) << 5; // Rn
 130         EncodedInst |= MCRI.getEncodingValue(MI.getOperand(0).getReg()); // Rd
 131
 132         SymbolLookUp(DisInfo, EncodedInst, &ReferenceType, Address,
 133                      &ReferenceName);
 134       }
 135       if (ReferenceType == LLVMDisassembler_ReferenceType_Out_LitPool_SymAddr)
 136         CommentStream << "literal pool symbol address: " << ReferenceName;
 137       else if (ReferenceType ==
 138                LLVMDisassembler_ReferenceType_Out_LitPool_CstrAddr) {
 139         CommentStream << "literal pool for: \"";
 140         CommentStream.write_escaped(ReferenceName);
 141         CommentStream << "\"";
 142       } else if (ReferenceType ==
 143                LLVMDisassembler_ReferenceType_Out_Objc_CFString_Ref)
 144         CommentStream << "Objc cfstring ref: @\"" << ReferenceName << "\"";
 145       else if (ReferenceType ==
 146                LLVMDisassembler_ReferenceType_Out_Objc_Message)
 147         CommentStream << "Objc message: " << ReferenceName;
 148       else if (ReferenceType ==
 149                LLVMDisassembler_ReferenceType_Out_Objc_Message_Ref)
 150         CommentStream << "Objc message ref: " << ReferenceName;
 151       else if (ReferenceType ==
 152                LLVMDisassembler_ReferenceType_Out_Objc_Selector_Ref)
 153         CommentStream << "Objc selector ref: " << ReferenceName;
 154       else if (ReferenceType ==
 155                LLVMDisassembler_ReferenceType_Out_Objc_Class_Ref)
 156         CommentStream << "Objc class ref: " << ReferenceName;
 157       // For these instructions, the SymbolLookUp() above is just to get the
 158       // ReferenceType and ReferenceName.  We want to make sure not to
 159       // fall through so we don't build an MCExpr to leave the disassembly
 160       // of the immediate values of these instructions to the InstPrinter.
 161       return false;
 162     } else {
 163       return false;
 164     }
 165   }
 166
 167   const MCExpr *Add = nullptr;
 168   if (SymbolicOp.AddSymbol.Present) {
 169     if (SymbolicOp.AddSymbol.Name) {
 170       StringRef Name(SymbolicOp.AddSymbol.Name);
 171       MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
 172       MCSymbolRefExpr::VariantKind Variant = getVariant(SymbolicOp.VariantKind);
 173       if (Variant != MCSymbolRefExpr::VK_None)
 174         Add = MCSymbolRefExpr::create(Sym, Variant, Ctx);
 175       else
 176         Add = MCSymbolRefExpr::create(Sym, Ctx);
 177     } else {
 178       Add = MCConstantExpr::create(SymbolicOp.AddSymbol.Value, Ctx);
 179     }
 180   }
 181
 182   const MCExpr *Sub = nullptr;
 183   if (SymbolicOp.SubtractSymbol.Present) {
 184     if (SymbolicOp.SubtractSymbol.Name) {
 185       StringRef Name(SymbolicOp.SubtractSymbol.Name);
 186       MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
 187       Sub = MCSymbolRefExpr::create(Sym, Ctx);
 188     } else {
 189       Sub = MCConstantExpr::create(SymbolicOp.SubtractSymbol.Value, Ctx);
 190     }
 191   }
 192
 193   const MCExpr *Off = nullptr;
 194   if (SymbolicOp.Value != 0)
 195     Off = MCConstantExpr::create(SymbolicOp.Value, Ctx);
 196
 197   const MCExpr *Expr;
 198   if (Sub) {
 199     const MCExpr *LHS;
 200     if (Add)
 201       LHS = MCBinaryExpr::createSub(Add, Sub, Ctx);
 202     else
 203       LHS = MCUnaryExpr::createMinus(Sub, Ctx);
 204     if (Off)
 205       Expr = MCBinaryExpr::createAdd(LHS, Off, Ctx);
 206     else
 207       Expr = LHS;
 208   } else if (Add) {
 209     if (Off)
 210       Expr = MCBinaryExpr::createAdd(Add, Off, Ctx);
 211     else
 212       Expr = Add;
 213   } else {
 214     if (Off)
 215       Expr = Off;
 216     else
 217       Expr = MCConstantExpr::create(0, Ctx);
 218   }
 219
 220   MI.addOperand(MCOperand::createExpr(Expr));
 221
 222   return true;
 223 }