X86MachORelocationInfo.cpp revision 2c94d0faa0e1c268893d5e04dc77e8a35889db00 
1//===-- X86MachORelocationInfo.cpp ----------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "MCTargetDesc/X86MCTargetDesc.h"
11#include "llvm/MC/MCContext.h"
12#include "llvm/MC/MCExpr.h"
13#include "llvm/MC/MCInst.h"
14#include "llvm/MC/MCSymbol.h"
15#include "llvm/MC/MCRelocationInfo.h"
16#include "llvm/Object/MachO.h"
17
18using namespace llvm;
19using namespace object;
20using namespace macho;
21
22namespace {
23class X86_64MachORelocationInfo : public MCRelocationInfo {
24public:
25  X86_64MachORelocationInfo(MCContext &Ctx) : MCRelocationInfo(Ctx) {}
26
27  const MCExpr *createExprForRelocation(RelocationRef Rel) {
28    const MachOObjectFile *Obj = cast<MachOObjectFile>(Rel.getObjectFile());
29
30    uint64_t RelType; Rel.getType(RelType);
31    SymbolRef SymRef; Rel.getSymbol(SymRef);
32
33    StringRef SymName; SymRef.getName(SymName);
34    uint64_t  SymAddr; SymRef.getAddress(SymAddr);
35
36    RelocationEntry RE = Obj->getRelocation(Rel.getRawDataRefImpl());
37    bool isPCRel = Obj->getAnyRelocationPCRel(RE);
38
39    MCSymbol *Sym = Ctx.GetOrCreateSymbol(SymName);
40    // FIXME: check that the value is actually the same.
41    if (Sym->isVariable() == false)
42      Sym->setVariableValue(MCConstantExpr::Create(SymAddr, Ctx));
43    const MCExpr *Expr = 0;
44
45    switch(RelType) {
46    case RIT_X86_64_TLV:
47      Expr = MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_TLVP, Ctx);
48      break;
49    case RIT_X86_64_Signed4:
50      Expr = MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Sym, Ctx),
51                                     MCConstantExpr::Create(4, Ctx),
52                                     Ctx);
53      break;
54    case RIT_X86_64_Signed2:
55      Expr = MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Sym, Ctx),
56                                     MCConstantExpr::Create(2, Ctx),
57                                     Ctx);
58      break;
59    case RIT_X86_64_Signed1:
60      Expr = MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(Sym, Ctx),
61                                     MCConstantExpr::Create(1, Ctx),
62                                     Ctx);
63      break;
64    case RIT_X86_64_GOTLoad:
65      Expr = MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_GOTPCREL, Ctx);
66      break;
67    case RIT_X86_64_GOT:
68      Expr = MCSymbolRefExpr::Create(Sym, isPCRel ?
69                                     MCSymbolRefExpr::VK_GOTPCREL :
70                                     MCSymbolRefExpr::VK_GOT,
71                                     Ctx);
72      break;
73    case RIT_X86_64_Subtractor:
74      {
75        RelocationRef RelNext;
76        Obj->getRelocationNext(Rel.getRawDataRefImpl(), RelNext);
77        RelocationEntry RENext = Obj->getRelocation(RelNext.getRawDataRefImpl());
78
79        // X86_64_SUBTRACTOR must be followed by a relocation of type
80        // X86_64_RELOC_UNSIGNED    .
81        // NOTE: Scattered relocations don't exist on x86_64.
82        unsigned RType = Obj->getAnyRelocationType(RENext);
83        if (RType != RIT_X86_64_Unsigned)
84          report_fatal_error("Expected X86_64_RELOC_UNSIGNED after "
85                             "X86_64_RELOC_SUBTRACTOR.");
86
87        const MCExpr *LHS = MCSymbolRefExpr::Create(Sym, Ctx);
88
89        SymbolRef RSymRef;
90        RelNext.getSymbol(RSymRef);
91        uint64_t RSymAddr;
92        RSymRef.getAddress(RSymAddr);
93        StringRef RSymName;
94        RSymRef.getName(RSymName);
95
96        MCSymbol *RSym = Ctx.GetOrCreateSymbol(RSymName);
97        if (RSym->isVariable() == false)
98          RSym->setVariableValue(MCConstantExpr::Create(RSymAddr, Ctx));
99
100        const MCExpr *RHS = MCSymbolRefExpr::Create(RSym, Ctx);
101
102        Expr = MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
103        break;
104      }
105    default:
106      Expr = MCSymbolRefExpr::Create(Sym, Ctx);
107      break;
108    }
109    return Expr;
110  }
111};
112} // End unnamed namespace
113
114/// createX86_64MachORelocationInfo - Construct an X86-64 Mach-O RelocationInfo.
115MCRelocationInfo *llvm::createX86_64MachORelocationInfo(MCContext &Ctx) {
116  return new X86_64MachORelocationInfo(Ctx);
117}
118