1 //===-- RuntimeDyldCOFF.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-==//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Implementation of COFF support for the MC-JIT runtime dynamic linker.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "RuntimeDyldCOFF.h"
14 #include "Targets/RuntimeDyldCOFFAArch64.h"
15 #include "Targets/RuntimeDyldCOFFI386.h"
16 #include "Targets/RuntimeDyldCOFFThumb.h"
17 #include "Targets/RuntimeDyldCOFFX86_64.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/Object/ObjectFile.h"
20 #include "llvm/Support/FormatVariadic.h"
21 #include "llvm/TargetParser/Triple.h"
22 
23 using namespace llvm;
24 using namespace llvm::object;
25 
26 #define DEBUG_TYPE "dyld"
27 
28 namespace {
29 
30 class LoadedCOFFObjectInfo final
31     : public LoadedObjectInfoHelper<LoadedCOFFObjectInfo,
32                                     RuntimeDyld::LoadedObjectInfo> {
33 public:
34   LoadedCOFFObjectInfo(
35       RuntimeDyldImpl &RTDyld,
36       RuntimeDyld::LoadedObjectInfo::ObjSectionToIDMap ObjSecToIDMap)
37       : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
38 
39   OwningBinary<ObjectFile>
40   getObjectForDebug(const ObjectFile &Obj) const override {
41     return OwningBinary<ObjectFile>();
42   }
43 };
44 }
45 
46 namespace llvm {
47 
48 std::unique_ptr<RuntimeDyldCOFF>
49 llvm::RuntimeDyldCOFF::create(Triple::ArchType Arch,
50                               RuntimeDyld::MemoryManager &MemMgr,
51                               JITSymbolResolver &Resolver) {
52   switch (Arch) {
53   default: llvm_unreachable("Unsupported target for RuntimeDyldCOFF.");
54   case Triple::x86:
55     return std::make_unique<RuntimeDyldCOFFI386>(MemMgr, Resolver);
56   case Triple::thumb:
57     return std::make_unique<RuntimeDyldCOFFThumb>(MemMgr, Resolver);
58   case Triple::x86_64:
59     return std::make_unique<RuntimeDyldCOFFX86_64>(MemMgr, Resolver);
60   case Triple::aarch64:
61     return std::make_unique<RuntimeDyldCOFFAArch64>(MemMgr, Resolver);
62   }
63 }
64 
65 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
66 RuntimeDyldCOFF::loadObject(const object::ObjectFile &O) {
67   if (auto ObjSectionToIDOrErr = loadObjectImpl(O)) {
68     return std::make_unique<LoadedCOFFObjectInfo>(*this, *ObjSectionToIDOrErr);
69   } else {
70     HasError = true;
71     raw_string_ostream ErrStream(ErrorStr);
72     logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream);
73     return nullptr;
74   }
75 }
76 
77 uint64_t RuntimeDyldCOFF::getSymbolOffset(const SymbolRef &Sym) {
78   // The value in a relocatable COFF object is the offset.
79   return cantFail(Sym.getValue());
80 }
81 
82 uint64_t RuntimeDyldCOFF::getDLLImportOffset(unsigned SectionID, StubMap &Stubs,
83                                              StringRef Name,
84                                              bool SetSectionIDMinus1) {
85   LLVM_DEBUG(dbgs() << "Getting DLLImport entry for " << Name << "... ");
86   assert(Name.startswith(getImportSymbolPrefix()) && "Not a DLLImport symbol?");
87   RelocationValueRef Reloc;
88   Reloc.SymbolName = Name.data();
89   auto I = Stubs.find(Reloc);
90   if (I != Stubs.end()) {
91     LLVM_DEBUG(dbgs() << format("{0:x8}", I->second) << "\n");
92     return I->second;
93   }
94 
95   assert(SectionID < Sections.size() && "SectionID out of range");
96   auto &Sec = Sections[SectionID];
97   auto EntryOffset = alignTo(Sec.getStubOffset(), PointerSize);
98   Sec.advanceStubOffset(EntryOffset + PointerSize - Sec.getStubOffset());
99   Stubs[Reloc] = EntryOffset;
100 
101   RelocationEntry RE(SectionID, EntryOffset, PointerReloc, 0, false,
102                      Log2_64(PointerSize));
103   // Hack to tell I386/Thumb resolveRelocation that this isn't section relative.
104   if (SetSectionIDMinus1)
105     RE.Sections.SectionA = -1;
106   addRelocationForSymbol(RE, Name.drop_front(getImportSymbolPrefix().size()));
107 
108   LLVM_DEBUG({
109     dbgs() << "Creating entry at "
110            << formatv("{0:x16} + {1:x8} ( {2:x16} )", Sec.getLoadAddress(),
111                       EntryOffset, Sec.getLoadAddress() + EntryOffset)
112            << "\n";
113   });
114   return EntryOffset;
115 }
116 
117 bool RuntimeDyldCOFF::isCompatibleFile(const object::ObjectFile &Obj) const {
118   return Obj.isCOFF();
119 }
120 
121 } // namespace llvm
122