You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
200 lines
8.3 KiB
200 lines
8.3 KiB
//===-- MCExternalSymbolizer.cpp - External symbolizer --------------------===//
|
|
//
|
|
// 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 "llvm/MC/MCDisassembler/MCExternalSymbolizer.h"
|
|
#include "llvm/MC/MCContext.h"
|
|
#include "llvm/MC/MCExpr.h"
|
|
#include "llvm/MC/MCInst.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
#include <cstring>
|
|
|
|
using namespace llvm;
|
|
|
|
namespace llvm {
|
|
class Triple;
|
|
}
|
|
|
|
// This function tries to add a symbolic operand in place of the immediate
|
|
// Value in the MCInst. The immediate Value has had any PC adjustment made by
|
|
// the caller. If the instruction is a branch instruction then IsBranch is true,
|
|
// else false. If the getOpInfo() function was set as part of the
|
|
// setupForSymbolicDisassembly() call then that function is called to get any
|
|
// symbolic information at the Address for this instruction. 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 true then a symbol look up for Value is done and if a symbol
|
|
// is found an MCExpr is created with that, else an MCExpr with Value is
|
|
// created. This function returns true if it adds an operand to the MCInst and
|
|
// false otherwise.
|
|
bool MCExternalSymbolizer::tryAddingSymbolicOperand(MCInst &MI,
|
|
raw_ostream &cStream,
|
|
int64_t Value,
|
|
uint64_t Address,
|
|
bool IsBranch,
|
|
uint64_t Offset,
|
|
uint64_t InstSize) {
|
|
struct LLVMOpInfo1 SymbolicOp;
|
|
std::memset(&SymbolicOp, '\0', sizeof(struct LLVMOpInfo1));
|
|
SymbolicOp.Value = Value;
|
|
|
|
if (!GetOpInfo ||
|
|
!GetOpInfo(DisInfo, Address, Offset, InstSize, 1, &SymbolicOp)) {
|
|
// Clear SymbolicOp.Value from above and also all other fields.
|
|
std::memset(&SymbolicOp, '\0', sizeof(struct LLVMOpInfo1));
|
|
|
|
// At this point, GetOpInfo() did not find any relocation information about
|
|
// this operand and we are left to use the SymbolLookUp() call back to guess
|
|
// if the Value is the address of a symbol. In the case this is a branch
|
|
// that always makes sense to guess. But in the case of an immediate it is
|
|
// a bit more questionable if it is an address of a symbol or some other
|
|
// reference. So if the immediate Value comes from a width of 1 byte,
|
|
// InstSize, we will not guess it is an address of a symbol. Because in
|
|
// object files assembled starting at address 0 this usually leads to
|
|
// incorrect symbolication.
|
|
if (!SymbolLookUp || (InstSize == 1 && !IsBranch))
|
|
return false;
|
|
|
|
uint64_t ReferenceType;
|
|
if (IsBranch)
|
|
ReferenceType = LLVMDisassembler_ReferenceType_In_Branch;
|
|
else
|
|
ReferenceType = LLVMDisassembler_ReferenceType_InOut_None;
|
|
const char *ReferenceName;
|
|
const char *Name = SymbolLookUp(DisInfo, Value, &ReferenceType, Address,
|
|
&ReferenceName);
|
|
if (Name) {
|
|
SymbolicOp.AddSymbol.Name = Name;
|
|
SymbolicOp.AddSymbol.Present = true;
|
|
// If Name is a C++ symbol name put the human readable name in a comment.
|
|
if(ReferenceType == LLVMDisassembler_ReferenceType_DeMangled_Name)
|
|
cStream << ReferenceName;
|
|
}
|
|
// For branches always create an MCExpr so it gets printed as hex address.
|
|
else if (IsBranch) {
|
|
SymbolicOp.Value = Value;
|
|
}
|
|
if(ReferenceType == LLVMDisassembler_ReferenceType_Out_SymbolStub)
|
|
cStream << "symbol stub for: " << ReferenceName;
|
|
else if(ReferenceType == LLVMDisassembler_ReferenceType_Out_Objc_Message)
|
|
cStream << "Objc message: " << ReferenceName;
|
|
if (!Name && !IsBranch)
|
|
return false;
|
|
}
|
|
|
|
const MCExpr *Add = nullptr;
|
|
if (SymbolicOp.AddSymbol.Present) {
|
|
if (SymbolicOp.AddSymbol.Name) {
|
|
StringRef Name(SymbolicOp.AddSymbol.Name);
|
|
MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
|
|
Add = MCSymbolRefExpr::create(Sym, Ctx);
|
|
} else {
|
|
Add = MCConstantExpr::create((int)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((int)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);
|
|
}
|
|
|
|
Expr = RelInfo->createExprForCAPIVariantKind(Expr, SymbolicOp.VariantKind);
|
|
if (!Expr)
|
|
return false;
|
|
|
|
MI.addOperand(MCOperand::createExpr(Expr));
|
|
return true;
|
|
}
|
|
|
|
// This function tries to add a comment as to what is being referenced by a load
|
|
// instruction with the base register that is the Pc. These can often be values
|
|
// in a literal pool near the Address of the instruction. The Address of the
|
|
// instruction and its immediate Value are used as a possible literal pool entry.
|
|
// The SymbolLookUp call back will return the name of a symbol referenced by the
|
|
// literal pool's entry if the referenced address is that of a symbol. Or it
|
|
// will return a pointer to a literal 'C' string if the referenced address of
|
|
// the literal pool's entry is an address into a section with C string literals.
|
|
// Or if the reference is to an Objective-C data structure it will return a
|
|
// specific reference type for it and a string.
|
|
void MCExternalSymbolizer::tryAddingPcLoadReferenceComment(raw_ostream &cStream,
|
|
int64_t Value,
|
|
uint64_t Address) {
|
|
if (SymbolLookUp) {
|
|
uint64_t ReferenceType = LLVMDisassembler_ReferenceType_In_PCrel_Load;
|
|
const char *ReferenceName;
|
|
(void)SymbolLookUp(DisInfo, Value, &ReferenceType, Address, &ReferenceName);
|
|
if(ReferenceType == LLVMDisassembler_ReferenceType_Out_LitPool_SymAddr)
|
|
cStream << "literal pool symbol address: " << ReferenceName;
|
|
else if(ReferenceType ==
|
|
LLVMDisassembler_ReferenceType_Out_LitPool_CstrAddr) {
|
|
cStream << "literal pool for: \"";
|
|
cStream.write_escaped(ReferenceName);
|
|
cStream << "\"";
|
|
}
|
|
else if(ReferenceType ==
|
|
LLVMDisassembler_ReferenceType_Out_Objc_CFString_Ref)
|
|
cStream << "Objc cfstring ref: @\"" << ReferenceName << "\"";
|
|
else if(ReferenceType ==
|
|
LLVMDisassembler_ReferenceType_Out_Objc_Message)
|
|
cStream << "Objc message: " << ReferenceName;
|
|
else if(ReferenceType ==
|
|
LLVMDisassembler_ReferenceType_Out_Objc_Message_Ref)
|
|
cStream << "Objc message ref: " << ReferenceName;
|
|
else if(ReferenceType ==
|
|
LLVMDisassembler_ReferenceType_Out_Objc_Selector_Ref)
|
|
cStream << "Objc selector ref: " << ReferenceName;
|
|
else if(ReferenceType ==
|
|
LLVMDisassembler_ReferenceType_Out_Objc_Class_Ref)
|
|
cStream << "Objc class ref: " << ReferenceName;
|
|
}
|
|
}
|
|
|
|
namespace llvm {
|
|
MCSymbolizer *createMCSymbolizer(const Triple &TT, LLVMOpInfoCallback GetOpInfo,
|
|
LLVMSymbolLookupCallback SymbolLookUp,
|
|
void *DisInfo, MCContext *Ctx,
|
|
std::unique_ptr<MCRelocationInfo> &&RelInfo) {
|
|
assert(Ctx && "No MCContext given for symbolic disassembly");
|
|
|
|
return new MCExternalSymbolizer(*Ctx, std::move(RelInfo), GetOpInfo,
|
|
SymbolLookUp, DisInfo);
|
|
}
|
|
}
|