1*9880d681SAndroid Build Coastguard Worker //===-- MCExternalSymbolizer.cpp - External symbolizer --------------------===//
2*9880d681SAndroid Build Coastguard Worker //
3*9880d681SAndroid Build Coastguard Worker // The LLVM Compiler Infrastructure
4*9880d681SAndroid Build Coastguard Worker //
5*9880d681SAndroid Build Coastguard Worker // This file is distributed under the University of Illinois Open Source
6*9880d681SAndroid Build Coastguard Worker // License. See LICENSE.TXT for details.
7*9880d681SAndroid Build Coastguard Worker //
8*9880d681SAndroid Build Coastguard Worker //===----------------------------------------------------------------------===//
9*9880d681SAndroid Build Coastguard Worker
10*9880d681SAndroid Build Coastguard Worker #include "llvm/MC/MCDisassembler/MCExternalSymbolizer.h"
11*9880d681SAndroid Build Coastguard Worker #include "llvm/MC/MCContext.h"
12*9880d681SAndroid Build Coastguard Worker #include "llvm/MC/MCExpr.h"
13*9880d681SAndroid Build Coastguard Worker #include "llvm/MC/MCInst.h"
14*9880d681SAndroid Build Coastguard Worker #include "llvm/Support/raw_ostream.h"
15*9880d681SAndroid Build Coastguard Worker #include <cstring>
16*9880d681SAndroid Build Coastguard Worker
17*9880d681SAndroid Build Coastguard Worker using namespace llvm;
18*9880d681SAndroid Build Coastguard Worker
19*9880d681SAndroid Build Coastguard Worker namespace llvm {
20*9880d681SAndroid Build Coastguard Worker class Triple;
21*9880d681SAndroid Build Coastguard Worker }
22*9880d681SAndroid Build Coastguard Worker
23*9880d681SAndroid Build Coastguard Worker // This function tries to add a symbolic operand in place of the immediate
24*9880d681SAndroid Build Coastguard Worker // Value in the MCInst. The immediate Value has had any PC adjustment made by
25*9880d681SAndroid Build Coastguard Worker // the caller. If the instruction is a branch instruction then IsBranch is true,
26*9880d681SAndroid Build Coastguard Worker // else false. If the getOpInfo() function was set as part of the
27*9880d681SAndroid Build Coastguard Worker // setupForSymbolicDisassembly() call then that function is called to get any
28*9880d681SAndroid Build Coastguard Worker // symbolic information at the Address for this instruction. If that returns
29*9880d681SAndroid Build Coastguard Worker // non-zero then the symbolic information it returns is used to create an MCExpr
30*9880d681SAndroid Build Coastguard Worker // and that is added as an operand to the MCInst. If getOpInfo() returns zero
31*9880d681SAndroid Build Coastguard Worker // and IsBranch is true then a symbol look up for Value is done and if a symbol
32*9880d681SAndroid Build Coastguard Worker // is found an MCExpr is created with that, else an MCExpr with Value is
33*9880d681SAndroid Build Coastguard Worker // created. This function returns true if it adds an operand to the MCInst and
34*9880d681SAndroid Build Coastguard Worker // false otherwise.
tryAddingSymbolicOperand(MCInst & MI,raw_ostream & cStream,int64_t Value,uint64_t Address,bool IsBranch,uint64_t Offset,uint64_t InstSize)35*9880d681SAndroid Build Coastguard Worker bool MCExternalSymbolizer::tryAddingSymbolicOperand(MCInst &MI,
36*9880d681SAndroid Build Coastguard Worker raw_ostream &cStream,
37*9880d681SAndroid Build Coastguard Worker int64_t Value,
38*9880d681SAndroid Build Coastguard Worker uint64_t Address,
39*9880d681SAndroid Build Coastguard Worker bool IsBranch,
40*9880d681SAndroid Build Coastguard Worker uint64_t Offset,
41*9880d681SAndroid Build Coastguard Worker uint64_t InstSize) {
42*9880d681SAndroid Build Coastguard Worker struct LLVMOpInfo1 SymbolicOp;
43*9880d681SAndroid Build Coastguard Worker std::memset(&SymbolicOp, '\0', sizeof(struct LLVMOpInfo1));
44*9880d681SAndroid Build Coastguard Worker SymbolicOp.Value = Value;
45*9880d681SAndroid Build Coastguard Worker
46*9880d681SAndroid Build Coastguard Worker if (!GetOpInfo ||
47*9880d681SAndroid Build Coastguard Worker !GetOpInfo(DisInfo, Address, Offset, InstSize, 1, &SymbolicOp)) {
48*9880d681SAndroid Build Coastguard Worker // Clear SymbolicOp.Value from above and also all other fields.
49*9880d681SAndroid Build Coastguard Worker std::memset(&SymbolicOp, '\0', sizeof(struct LLVMOpInfo1));
50*9880d681SAndroid Build Coastguard Worker
51*9880d681SAndroid Build Coastguard Worker // At this point, GetOpInfo() did not find any relocation information about
52*9880d681SAndroid Build Coastguard Worker // this operand and we are left to use the SymbolLookUp() call back to guess
53*9880d681SAndroid Build Coastguard Worker // if the Value is the address of a symbol. In the case this is a branch
54*9880d681SAndroid Build Coastguard Worker // that always makes sense to guess. But in the case of an immediate it is
55*9880d681SAndroid Build Coastguard Worker // a bit more questionable if it is an address of a symbol or some other
56*9880d681SAndroid Build Coastguard Worker // reference. So if the immediate Value comes from a width of 1 byte,
57*9880d681SAndroid Build Coastguard Worker // InstSize, we will not guess it is an address of a symbol. Because in
58*9880d681SAndroid Build Coastguard Worker // object files assembled starting at address 0 this usually leads to
59*9880d681SAndroid Build Coastguard Worker // incorrect symbolication.
60*9880d681SAndroid Build Coastguard Worker if (!SymbolLookUp || (InstSize == 1 && !IsBranch))
61*9880d681SAndroid Build Coastguard Worker return false;
62*9880d681SAndroid Build Coastguard Worker
63*9880d681SAndroid Build Coastguard Worker uint64_t ReferenceType;
64*9880d681SAndroid Build Coastguard Worker if (IsBranch)
65*9880d681SAndroid Build Coastguard Worker ReferenceType = LLVMDisassembler_ReferenceType_In_Branch;
66*9880d681SAndroid Build Coastguard Worker else
67*9880d681SAndroid Build Coastguard Worker ReferenceType = LLVMDisassembler_ReferenceType_InOut_None;
68*9880d681SAndroid Build Coastguard Worker const char *ReferenceName;
69*9880d681SAndroid Build Coastguard Worker const char *Name = SymbolLookUp(DisInfo, Value, &ReferenceType, Address,
70*9880d681SAndroid Build Coastguard Worker &ReferenceName);
71*9880d681SAndroid Build Coastguard Worker if (Name) {
72*9880d681SAndroid Build Coastguard Worker SymbolicOp.AddSymbol.Name = Name;
73*9880d681SAndroid Build Coastguard Worker SymbolicOp.AddSymbol.Present = true;
74*9880d681SAndroid Build Coastguard Worker // If Name is a C++ symbol name put the human readable name in a comment.
75*9880d681SAndroid Build Coastguard Worker if(ReferenceType == LLVMDisassembler_ReferenceType_DeMangled_Name)
76*9880d681SAndroid Build Coastguard Worker cStream << ReferenceName;
77*9880d681SAndroid Build Coastguard Worker }
78*9880d681SAndroid Build Coastguard Worker // For branches always create an MCExpr so it gets printed as hex address.
79*9880d681SAndroid Build Coastguard Worker else if (IsBranch) {
80*9880d681SAndroid Build Coastguard Worker SymbolicOp.Value = Value;
81*9880d681SAndroid Build Coastguard Worker }
82*9880d681SAndroid Build Coastguard Worker if(ReferenceType == LLVMDisassembler_ReferenceType_Out_SymbolStub)
83*9880d681SAndroid Build Coastguard Worker cStream << "symbol stub for: " << ReferenceName;
84*9880d681SAndroid Build Coastguard Worker else if(ReferenceType == LLVMDisassembler_ReferenceType_Out_Objc_Message)
85*9880d681SAndroid Build Coastguard Worker cStream << "Objc message: " << ReferenceName;
86*9880d681SAndroid Build Coastguard Worker if (!Name && !IsBranch)
87*9880d681SAndroid Build Coastguard Worker return false;
88*9880d681SAndroid Build Coastguard Worker }
89*9880d681SAndroid Build Coastguard Worker
90*9880d681SAndroid Build Coastguard Worker const MCExpr *Add = nullptr;
91*9880d681SAndroid Build Coastguard Worker if (SymbolicOp.AddSymbol.Present) {
92*9880d681SAndroid Build Coastguard Worker if (SymbolicOp.AddSymbol.Name) {
93*9880d681SAndroid Build Coastguard Worker StringRef Name(SymbolicOp.AddSymbol.Name);
94*9880d681SAndroid Build Coastguard Worker MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
95*9880d681SAndroid Build Coastguard Worker Add = MCSymbolRefExpr::create(Sym, Ctx);
96*9880d681SAndroid Build Coastguard Worker } else {
97*9880d681SAndroid Build Coastguard Worker Add = MCConstantExpr::create((int)SymbolicOp.AddSymbol.Value, Ctx);
98*9880d681SAndroid Build Coastguard Worker }
99*9880d681SAndroid Build Coastguard Worker }
100*9880d681SAndroid Build Coastguard Worker
101*9880d681SAndroid Build Coastguard Worker const MCExpr *Sub = nullptr;
102*9880d681SAndroid Build Coastguard Worker if (SymbolicOp.SubtractSymbol.Present) {
103*9880d681SAndroid Build Coastguard Worker if (SymbolicOp.SubtractSymbol.Name) {
104*9880d681SAndroid Build Coastguard Worker StringRef Name(SymbolicOp.SubtractSymbol.Name);
105*9880d681SAndroid Build Coastguard Worker MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
106*9880d681SAndroid Build Coastguard Worker Sub = MCSymbolRefExpr::create(Sym, Ctx);
107*9880d681SAndroid Build Coastguard Worker } else {
108*9880d681SAndroid Build Coastguard Worker Sub = MCConstantExpr::create((int)SymbolicOp.SubtractSymbol.Value, Ctx);
109*9880d681SAndroid Build Coastguard Worker }
110*9880d681SAndroid Build Coastguard Worker }
111*9880d681SAndroid Build Coastguard Worker
112*9880d681SAndroid Build Coastguard Worker const MCExpr *Off = nullptr;
113*9880d681SAndroid Build Coastguard Worker if (SymbolicOp.Value != 0)
114*9880d681SAndroid Build Coastguard Worker Off = MCConstantExpr::create(SymbolicOp.Value, Ctx);
115*9880d681SAndroid Build Coastguard Worker
116*9880d681SAndroid Build Coastguard Worker const MCExpr *Expr;
117*9880d681SAndroid Build Coastguard Worker if (Sub) {
118*9880d681SAndroid Build Coastguard Worker const MCExpr *LHS;
119*9880d681SAndroid Build Coastguard Worker if (Add)
120*9880d681SAndroid Build Coastguard Worker LHS = MCBinaryExpr::createSub(Add, Sub, Ctx);
121*9880d681SAndroid Build Coastguard Worker else
122*9880d681SAndroid Build Coastguard Worker LHS = MCUnaryExpr::createMinus(Sub, Ctx);
123*9880d681SAndroid Build Coastguard Worker if (Off)
124*9880d681SAndroid Build Coastguard Worker Expr = MCBinaryExpr::createAdd(LHS, Off, Ctx);
125*9880d681SAndroid Build Coastguard Worker else
126*9880d681SAndroid Build Coastguard Worker Expr = LHS;
127*9880d681SAndroid Build Coastguard Worker } else if (Add) {
128*9880d681SAndroid Build Coastguard Worker if (Off)
129*9880d681SAndroid Build Coastguard Worker Expr = MCBinaryExpr::createAdd(Add, Off, Ctx);
130*9880d681SAndroid Build Coastguard Worker else
131*9880d681SAndroid Build Coastguard Worker Expr = Add;
132*9880d681SAndroid Build Coastguard Worker } else {
133*9880d681SAndroid Build Coastguard Worker if (Off)
134*9880d681SAndroid Build Coastguard Worker Expr = Off;
135*9880d681SAndroid Build Coastguard Worker else
136*9880d681SAndroid Build Coastguard Worker Expr = MCConstantExpr::create(0, Ctx);
137*9880d681SAndroid Build Coastguard Worker }
138*9880d681SAndroid Build Coastguard Worker
139*9880d681SAndroid Build Coastguard Worker Expr = RelInfo->createExprForCAPIVariantKind(Expr, SymbolicOp.VariantKind);
140*9880d681SAndroid Build Coastguard Worker if (!Expr)
141*9880d681SAndroid Build Coastguard Worker return false;
142*9880d681SAndroid Build Coastguard Worker
143*9880d681SAndroid Build Coastguard Worker MI.addOperand(MCOperand::createExpr(Expr));
144*9880d681SAndroid Build Coastguard Worker return true;
145*9880d681SAndroid Build Coastguard Worker }
146*9880d681SAndroid Build Coastguard Worker
147*9880d681SAndroid Build Coastguard Worker // This function tries to add a comment as to what is being referenced by a load
148*9880d681SAndroid Build Coastguard Worker // instruction with the base register that is the Pc. These can often be values
149*9880d681SAndroid Build Coastguard Worker // in a literal pool near the Address of the instruction. The Address of the
150*9880d681SAndroid Build Coastguard Worker // instruction and its immediate Value are used as a possible literal pool entry.
151*9880d681SAndroid Build Coastguard Worker // The SymbolLookUp call back will return the name of a symbol referenced by the
152*9880d681SAndroid Build Coastguard Worker // literal pool's entry if the referenced address is that of a symbol. Or it
153*9880d681SAndroid Build Coastguard Worker // will return a pointer to a literal 'C' string if the referenced address of
154*9880d681SAndroid Build Coastguard Worker // the literal pool's entry is an address into a section with C string literals.
155*9880d681SAndroid Build Coastguard Worker // Or if the reference is to an Objective-C data structure it will return a
156*9880d681SAndroid Build Coastguard Worker // specific reference type for it and a string.
tryAddingPcLoadReferenceComment(raw_ostream & cStream,int64_t Value,uint64_t Address)157*9880d681SAndroid Build Coastguard Worker void MCExternalSymbolizer::tryAddingPcLoadReferenceComment(raw_ostream &cStream,
158*9880d681SAndroid Build Coastguard Worker int64_t Value,
159*9880d681SAndroid Build Coastguard Worker uint64_t Address) {
160*9880d681SAndroid Build Coastguard Worker if (SymbolLookUp) {
161*9880d681SAndroid Build Coastguard Worker uint64_t ReferenceType = LLVMDisassembler_ReferenceType_In_PCrel_Load;
162*9880d681SAndroid Build Coastguard Worker const char *ReferenceName;
163*9880d681SAndroid Build Coastguard Worker (void)SymbolLookUp(DisInfo, Value, &ReferenceType, Address, &ReferenceName);
164*9880d681SAndroid Build Coastguard Worker if(ReferenceType == LLVMDisassembler_ReferenceType_Out_LitPool_SymAddr)
165*9880d681SAndroid Build Coastguard Worker cStream << "literal pool symbol address: " << ReferenceName;
166*9880d681SAndroid Build Coastguard Worker else if(ReferenceType ==
167*9880d681SAndroid Build Coastguard Worker LLVMDisassembler_ReferenceType_Out_LitPool_CstrAddr) {
168*9880d681SAndroid Build Coastguard Worker cStream << "literal pool for: \"";
169*9880d681SAndroid Build Coastguard Worker cStream.write_escaped(ReferenceName);
170*9880d681SAndroid Build Coastguard Worker cStream << "\"";
171*9880d681SAndroid Build Coastguard Worker }
172*9880d681SAndroid Build Coastguard Worker else if(ReferenceType ==
173*9880d681SAndroid Build Coastguard Worker LLVMDisassembler_ReferenceType_Out_Objc_CFString_Ref)
174*9880d681SAndroid Build Coastguard Worker cStream << "Objc cfstring ref: @\"" << ReferenceName << "\"";
175*9880d681SAndroid Build Coastguard Worker else if(ReferenceType ==
176*9880d681SAndroid Build Coastguard Worker LLVMDisassembler_ReferenceType_Out_Objc_Message)
177*9880d681SAndroid Build Coastguard Worker cStream << "Objc message: " << ReferenceName;
178*9880d681SAndroid Build Coastguard Worker else if(ReferenceType ==
179*9880d681SAndroid Build Coastguard Worker LLVMDisassembler_ReferenceType_Out_Objc_Message_Ref)
180*9880d681SAndroid Build Coastguard Worker cStream << "Objc message ref: " << ReferenceName;
181*9880d681SAndroid Build Coastguard Worker else if(ReferenceType ==
182*9880d681SAndroid Build Coastguard Worker LLVMDisassembler_ReferenceType_Out_Objc_Selector_Ref)
183*9880d681SAndroid Build Coastguard Worker cStream << "Objc selector ref: " << ReferenceName;
184*9880d681SAndroid Build Coastguard Worker else if(ReferenceType ==
185*9880d681SAndroid Build Coastguard Worker LLVMDisassembler_ReferenceType_Out_Objc_Class_Ref)
186*9880d681SAndroid Build Coastguard Worker cStream << "Objc class ref: " << ReferenceName;
187*9880d681SAndroid Build Coastguard Worker }
188*9880d681SAndroid Build Coastguard Worker }
189*9880d681SAndroid Build Coastguard Worker
190*9880d681SAndroid Build Coastguard Worker namespace llvm {
createMCSymbolizer(const Triple & TT,LLVMOpInfoCallback GetOpInfo,LLVMSymbolLookupCallback SymbolLookUp,void * DisInfo,MCContext * Ctx,std::unique_ptr<MCRelocationInfo> && RelInfo)191*9880d681SAndroid Build Coastguard Worker MCSymbolizer *createMCSymbolizer(const Triple &TT, LLVMOpInfoCallback GetOpInfo,
192*9880d681SAndroid Build Coastguard Worker LLVMSymbolLookupCallback SymbolLookUp,
193*9880d681SAndroid Build Coastguard Worker void *DisInfo, MCContext *Ctx,
194*9880d681SAndroid Build Coastguard Worker std::unique_ptr<MCRelocationInfo> &&RelInfo) {
195*9880d681SAndroid Build Coastguard Worker assert(Ctx && "No MCContext given for symbolic disassembly");
196*9880d681SAndroid Build Coastguard Worker
197*9880d681SAndroid Build Coastguard Worker return new MCExternalSymbolizer(*Ctx, std::move(RelInfo), GetOpInfo,
198*9880d681SAndroid Build Coastguard Worker SymbolLookUp, DisInfo);
199*9880d681SAndroid Build Coastguard Worker }
200*9880d681SAndroid Build Coastguard Worker }
201