xref: /aosp_15_r20/external/llvm/lib/MC/MCDisassembler/MCExternalSymbolizer.cpp (revision 9880d6810fe72a1726cb53787c6711e909410d58)
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