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//===- AArch64ExternalSymbolizer.cpp - Symbolizer for AArch64 ---*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "AArch64ExternalSymbolizer.h"
#include "MCTargetDesc/AArch64AddressingModes.h"
#include "Utils/AArch64BaseInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DEBUG_TYPE "aarch64-disassembler"
static MCSymbolRefExpr::VariantKind
getVariant(uint64_t LLVMDisassembler_VariantKind) {
switch (LLVMDisassembler_VariantKind) {
case LLVMDisassembler_VariantKind_None:
return MCSymbolRefExpr::VK_None;
case LLVMDisassembler_VariantKind_ARM64_PAGE:
return MCSymbolRefExpr::VK_PAGE;
case LLVMDisassembler_VariantKind_ARM64_PAGEOFF:
return MCSymbolRefExpr::VK_PAGEOFF;
case LLVMDisassembler_VariantKind_ARM64_GOTPAGE:
return MCSymbolRefExpr::VK_GOTPAGE;
case LLVMDisassembler_VariantKind_ARM64_GOTPAGEOFF:
return MCSymbolRefExpr::VK_GOTPAGEOFF;
case LLVMDisassembler_VariantKind_ARM64_TLVP:
return MCSymbolRefExpr::VK_TLVPPAGE;
case LLVMDisassembler_VariantKind_ARM64_TLVOFF:
return MCSymbolRefExpr::VK_TLVPPAGEOFF;
default:
llvm_unreachable("bad LLVMDisassembler_VariantKind");
}
}
/// tryAddingSymbolicOperand - tryAddingSymbolicOperand trys to add a symbolic
/// operand in place of the immediate Value in the MCInst. The immediate
/// Value has not had any PC adjustment made by the caller. If the instruction
/// is a branch that adds the PC to the immediate Value then isBranch is
/// Success, else Fail. If GetOpInfo is non-null, then it is called to get any
/// symbolic information at the Address for this instrution. If that returns
/// non-zero then the symbolic information it returns is used to create an
/// MCExpr and that is added as an operand to the MCInst. If GetOpInfo()
/// returns zero and isBranch is Success then a symbol look up for
/// Address + Value is done and if a symbol is found an MCExpr is created with
/// that, else an MCExpr with Address + Value is created. If GetOpInfo()
/// returns zero and isBranch is Fail then the Opcode of the MCInst is
/// tested and for ADRP an other instructions that help to load of pointers
/// a symbol look up is done to see it is returns a specific reference type
/// to add to the comment stream. This function returns Success if it adds
/// an operand to the MCInst and Fail otherwise.
bool AArch64ExternalSymbolizer::tryAddingSymbolicOperand(
MCInst &MI, raw_ostream &CommentStream, int64_t Value, uint64_t Address,
bool IsBranch, uint64_t Offset, uint64_t OpSize, uint64_t InstSize) {
if (!SymbolLookUp)
return false;
// FIXME: This method shares a lot of code with
// MCExternalSymbolizer::tryAddingSymbolicOperand. It may be possible
// refactor the MCExternalSymbolizer interface to allow more of this
// implementation to be shared.
//
struct LLVMOpInfo1 SymbolicOp;
memset(&SymbolicOp, '\0', sizeof(struct LLVMOpInfo1));
SymbolicOp.Value = Value;
uint64_t ReferenceType;
const char *ReferenceName;
if (!GetOpInfo || !GetOpInfo(DisInfo, Address, /*Offset=*/0, OpSize, InstSize,
1, &SymbolicOp)) {
if (IsBranch) {
ReferenceType = LLVMDisassembler_ReferenceType_In_Branch;
const char *Name = SymbolLookUp(DisInfo, Address + Value, &ReferenceType,
Address, &ReferenceName);
if (Name) {
SymbolicOp.AddSymbol.Name = Name;
SymbolicOp.AddSymbol.Present = true;
SymbolicOp.Value = 0;
} else {
SymbolicOp.Value = Address + Value;
}
if (ReferenceType == LLVMDisassembler_ReferenceType_Out_SymbolStub)
CommentStream << "symbol stub for: " << ReferenceName;
else if (ReferenceType ==
LLVMDisassembler_ReferenceType_Out_Objc_Message)
CommentStream << "Objc message: " << ReferenceName;
} else if (MI.getOpcode() == AArch64::ADRP) {
ReferenceType = LLVMDisassembler_ReferenceType_In_ARM64_ADRP;
// otool expects the fully encoded ADRP instruction to be passed in as
// the value here, so reconstruct it:
const MCRegisterInfo &MCRI = *Ctx.getRegisterInfo();
uint32_t EncodedInst = 0x90000000;
EncodedInst |= (Value & 0x3) << 29; // immlo
EncodedInst |= ((Value >> 2) & 0x7FFFF) << 5; // immhi
EncodedInst |= MCRI.getEncodingValue(MI.getOperand(0).getReg()); // reg
SymbolLookUp(DisInfo, EncodedInst, &ReferenceType, Address,
&ReferenceName);
CommentStream << format("0x%llx", (0xfffffffffffff000LL & Address) +
Value * 0x1000);
} else if (MI.getOpcode() == AArch64::ADDXri ||
MI.getOpcode() == AArch64::LDRXui ||
MI.getOpcode() == AArch64::LDRXl ||
MI.getOpcode() == AArch64::ADR) {
if (MI.getOpcode() == AArch64::ADDXri)
ReferenceType = LLVMDisassembler_ReferenceType_In_ARM64_ADDXri;
else if (MI.getOpcode() == AArch64::LDRXui)
ReferenceType = LLVMDisassembler_ReferenceType_In_ARM64_LDRXui;
if (MI.getOpcode() == AArch64::LDRXl) {
ReferenceType = LLVMDisassembler_ReferenceType_In_ARM64_LDRXl;
SymbolLookUp(DisInfo, Address + Value, &ReferenceType, Address,
&ReferenceName);
} else if (MI.getOpcode() == AArch64::ADR) {
ReferenceType = LLVMDisassembler_ReferenceType_In_ARM64_ADR;
SymbolLookUp(DisInfo, Address + Value, &ReferenceType, Address,
&ReferenceName);
} else {
const MCRegisterInfo &MCRI = *Ctx.getRegisterInfo();
// otool expects the fully encoded ADD/LDR instruction to be passed in
// as the value here, so reconstruct it:
unsigned EncodedInst =
MI.getOpcode() == AArch64::ADDXri ? 0x91000000: 0xF9400000;
EncodedInst |= Value << 10; // imm12 [+ shift:2 for ADD]
EncodedInst |=
MCRI.getEncodingValue(MI.getOperand(1).getReg()) << 5; // Rn
EncodedInst |= MCRI.getEncodingValue(MI.getOperand(0).getReg()); // Rd
SymbolLookUp(DisInfo, EncodedInst, &ReferenceType, Address,
&ReferenceName);
}
if (ReferenceType == LLVMDisassembler_ReferenceType_Out_LitPool_SymAddr)
CommentStream << "literal pool symbol address: " << ReferenceName;
else if (ReferenceType ==
LLVMDisassembler_ReferenceType_Out_LitPool_CstrAddr) {
CommentStream << "literal pool for: \"";
CommentStream.write_escaped(ReferenceName);
CommentStream << "\"";
} else if (ReferenceType ==
LLVMDisassembler_ReferenceType_Out_Objc_CFString_Ref)
CommentStream << "Objc cfstring ref: @\"" << ReferenceName << "\"";
else if (ReferenceType ==
LLVMDisassembler_ReferenceType_Out_Objc_Message)
CommentStream << "Objc message: " << ReferenceName;
else if (ReferenceType ==
LLVMDisassembler_ReferenceType_Out_Objc_Message_Ref)
CommentStream << "Objc message ref: " << ReferenceName;
else if (ReferenceType ==
LLVMDisassembler_ReferenceType_Out_Objc_Selector_Ref)
CommentStream << "Objc selector ref: " << ReferenceName;
else if (ReferenceType ==
LLVMDisassembler_ReferenceType_Out_Objc_Class_Ref)
CommentStream << "Objc class ref: " << ReferenceName;
// For these instructions, the SymbolLookUp() above is just to get the
// ReferenceType and ReferenceName. We want to make sure not to
// fall through so we don't build an MCExpr to leave the disassembly
// of the immediate values of these instructions to the InstPrinter.
return false;
} else {
return false;
}
}
const MCExpr *Add = nullptr;
if (SymbolicOp.AddSymbol.Present) {
if (SymbolicOp.AddSymbol.Name) {
StringRef Name(SymbolicOp.AddSymbol.Name);
MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
MCSymbolRefExpr::VariantKind Variant = getVariant(SymbolicOp.VariantKind);
if (Variant != MCSymbolRefExpr::VK_None)
Add = MCSymbolRefExpr::create(Sym, Variant, Ctx);
else
Add = MCSymbolRefExpr::create(Sym, Ctx);
} else {
Add = MCConstantExpr::create(SymbolicOp.AddSymbol.Value, Ctx);
}
}
const MCExpr *Sub = nullptr;
if (SymbolicOp.SubtractSymbol.Present) {
if (SymbolicOp.SubtractSymbol.Name) {
StringRef Name(SymbolicOp.SubtractSymbol.Name);
MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
Sub = MCSymbolRefExpr::create(Sym, Ctx);
} else {
Sub = MCConstantExpr::create(SymbolicOp.SubtractSymbol.Value, Ctx);
}
}
const MCExpr *Off = nullptr;
if (SymbolicOp.Value != 0)
Off = MCConstantExpr::create(SymbolicOp.Value, Ctx);
const MCExpr *Expr;
if (Sub) {
const MCExpr *LHS;
if (Add)
LHS = MCBinaryExpr::createSub(Add, Sub, Ctx);
else
LHS = MCUnaryExpr::createMinus(Sub, Ctx);
if (Off)
Expr = MCBinaryExpr::createAdd(LHS, Off, Ctx);
else
Expr = LHS;
} else if (Add) {
if (Off)
Expr = MCBinaryExpr::createAdd(Add, Off, Ctx);
else
Expr = Add;
} else {
if (Off)
Expr = Off;
else
Expr = MCConstantExpr::create(0, Ctx);
}
MI.addOperand(MCOperand::createExpr(Expr));
return true;
}
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