1 //===-- COFFDump.cpp - COFF-specific dumper ---------------------*- C++ -*-===//
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 /// \file
11 /// \brief This file implements the COFF-specific dumper for llvm-objdump.
12 /// It outputs the Win64 EH data structures as plain text.
13 /// The encoding of the unwind codes is described in MSDN:
14 /// http://msdn.microsoft.com/en-us/library/ck9asaa9.aspx
15 ///
16 //===----------------------------------------------------------------------===//
17 
18 #include "llvm-objdump.h"
19 #include "llvm/Object/COFF.h"
20 #include "llvm/Object/ObjectFile.h"
21 #include "llvm/Support/Format.h"
22 #include "llvm/Support/SourceMgr.h"
23 #include "llvm/Support/Win64EH.h"
24 #include "llvm/Support/raw_ostream.h"
25 #include "llvm/Support/system_error.h"
26 #include <algorithm>
27 #include <cstring>
28 
29 using namespace llvm;
30 using namespace object;
31 using namespace llvm::Win64EH;
32 
33 // Returns the name of the unwind code.
34 static StringRef getUnwindCodeTypeName(uint8_t Code) {
35   switch(Code) {
36   default: llvm_unreachable("Invalid unwind code");
37   case UOP_PushNonVol: return "UOP_PushNonVol";
38   case UOP_AllocLarge: return "UOP_AllocLarge";
39   case UOP_AllocSmall: return "UOP_AllocSmall";
40   case UOP_SetFPReg: return "UOP_SetFPReg";
41   case UOP_SaveNonVol: return "UOP_SaveNonVol";
42   case UOP_SaveNonVolBig: return "UOP_SaveNonVolBig";
43   case UOP_SaveXMM128: return "UOP_SaveXMM128";
44   case UOP_SaveXMM128Big: return "UOP_SaveXMM128Big";
45   case UOP_PushMachFrame: return "UOP_PushMachFrame";
46   }
47 }
48 
49 // Returns the name of a referenced register.
50 static StringRef getUnwindRegisterName(uint8_t Reg) {
51   switch(Reg) {
52   default: llvm_unreachable("Invalid register");
53   case 0: return "RAX";
54   case 1: return "RCX";
55   case 2: return "RDX";
56   case 3: return "RBX";
57   case 4: return "RSP";
58   case 5: return "RBP";
59   case 6: return "RSI";
60   case 7: return "RDI";
61   case 8: return "R8";
62   case 9: return "R9";
63   case 10: return "R10";
64   case 11: return "R11";
65   case 12: return "R12";
66   case 13: return "R13";
67   case 14: return "R14";
68   case 15: return "R15";
69   }
70 }
71 
72 // Calculates the number of array slots required for the unwind code.
73 static unsigned getNumUsedSlots(const UnwindCode &UnwindCode) {
74   switch (UnwindCode.getUnwindOp()) {
75   default: llvm_unreachable("Invalid unwind code");
76   case UOP_PushNonVol:
77   case UOP_AllocSmall:
78   case UOP_SetFPReg:
79   case UOP_PushMachFrame:
80     return 1;
81   case UOP_SaveNonVol:
82   case UOP_SaveXMM128:
83     return 2;
84   case UOP_SaveNonVolBig:
85   case UOP_SaveXMM128Big:
86     return 3;
87   case UOP_AllocLarge:
88     return (UnwindCode.getOpInfo() == 0) ? 2 : 3;
89   }
90 }
91 
92 // Prints one unwind code. Because an unwind code can occupy up to 3 slots in
93 // the unwind codes array, this function requires that the correct number of
94 // slots is provided.
95 static void printUnwindCode(ArrayRef<UnwindCode> UCs) {
96   assert(UCs.size() >= getNumUsedSlots(UCs[0]));
97   outs() <<  format("    0x%02x: ", unsigned(UCs[0].u.CodeOffset))
98          << getUnwindCodeTypeName(UCs[0].getUnwindOp());
99   switch (UCs[0].getUnwindOp()) {
100   case UOP_PushNonVol:
101     outs() << " " << getUnwindRegisterName(UCs[0].getOpInfo());
102     break;
103   case UOP_AllocLarge:
104     if (UCs[0].getOpInfo() == 0) {
105       outs() << " " << UCs[1].FrameOffset;
106     } else {
107       outs() << " " << UCs[1].FrameOffset
108                        + (static_cast<uint32_t>(UCs[2].FrameOffset) << 16);
109     }
110     break;
111   case UOP_AllocSmall:
112     outs() << " " << ((UCs[0].getOpInfo() + 1) * 8);
113     break;
114   case UOP_SetFPReg:
115     outs() << " ";
116     break;
117   case UOP_SaveNonVol:
118     outs() << " " << getUnwindRegisterName(UCs[0].getOpInfo())
119            << format(" [0x%04x]", 8 * UCs[1].FrameOffset);
120     break;
121   case UOP_SaveNonVolBig:
122     outs() << " " << getUnwindRegisterName(UCs[0].getOpInfo())
123            << format(" [0x%08x]", UCs[1].FrameOffset
124                     + (static_cast<uint32_t>(UCs[2].FrameOffset) << 16));
125     break;
126   case UOP_SaveXMM128:
127     outs() << " XMM" << static_cast<uint32_t>(UCs[0].getOpInfo())
128            << format(" [0x%04x]", 16 * UCs[1].FrameOffset);
129     break;
130   case UOP_SaveXMM128Big:
131     outs() << " XMM" << UCs[0].getOpInfo()
132            << format(" [0x%08x]", UCs[1].FrameOffset
133                            + (static_cast<uint32_t>(UCs[2].FrameOffset) << 16));
134     break;
135   case UOP_PushMachFrame:
136     outs() << " " << (UCs[0].getOpInfo() ? "w/o" : "w")
137            << " error code";
138     break;
139   }
140   outs() << "\n";
141 }
142 
143 static void printAllUnwindCodes(ArrayRef<UnwindCode> UCs) {
144   for (const UnwindCode *I = UCs.begin(), *E = UCs.end(); I < E; ) {
145     unsigned UsedSlots = getNumUsedSlots(*I);
146     if (UsedSlots > UCs.size()) {
147       outs() << "Unwind data corrupted: Encountered unwind op "
148              << getUnwindCodeTypeName((*I).getUnwindOp())
149              << " which requires " << UsedSlots
150              << " slots, but only " << UCs.size()
151              << " remaining in buffer";
152       return ;
153     }
154     printUnwindCode(ArrayRef<UnwindCode>(I, E));
155     I += UsedSlots;
156   }
157 }
158 
159 // Given a symbol sym this functions returns the address and section of it.
160 static error_code resolveSectionAndAddress(const COFFObjectFile *Obj,
161                                            const SymbolRef &Sym,
162                                            const coff_section *&ResolvedSection,
163                                            uint64_t &ResolvedAddr) {
164   if (error_code EC = Sym.getAddress(ResolvedAddr))
165     return EC;
166   section_iterator iter(Obj->section_begin());
167   if (error_code EC = Sym.getSection(iter))
168     return EC;
169   ResolvedSection = Obj->getCOFFSection(iter);
170   return object_error::success;
171 }
172 
173 // Given a vector of relocations for a section and an offset into this section
174 // the function returns the symbol used for the relocation at the offset.
175 static error_code resolveSymbol(const std::vector<RelocationRef> &Rels,
176                                 uint64_t Offset, SymbolRef &Sym) {
177   for (std::vector<RelocationRef>::const_iterator I = Rels.begin(),
178                                                   E = Rels.end();
179                                                   I != E; ++I) {
180     uint64_t Ofs;
181     if (error_code EC = I->getOffset(Ofs))
182       return EC;
183     if (Ofs == Offset) {
184       Sym = *I->getSymbol();
185       break;
186     }
187   }
188   return object_error::success;
189 }
190 
191 // Given a vector of relocations for a section and an offset into this section
192 // the function resolves the symbol used for the relocation at the offset and
193 // returns the section content and the address inside the content pointed to
194 // by the symbol.
195 static error_code getSectionContents(const COFFObjectFile *Obj,
196                                      const std::vector<RelocationRef> &Rels,
197                                      uint64_t Offset,
198                                      ArrayRef<uint8_t> &Contents,
199                                      uint64_t &Addr) {
200   SymbolRef Sym;
201   if (error_code ec = resolveSymbol(Rels, Offset, Sym)) return ec;
202   const coff_section *Section;
203   if (error_code EC = resolveSectionAndAddress(Obj, Sym, Section, Addr))
204     return EC;
205   if (error_code EC = Obj->getSectionContents(Section, Contents))
206     return EC;
207   return object_error::success;
208 }
209 
210 // Given a vector of relocations for a section and an offset into this section
211 // the function returns the name of the symbol used for the relocation at the
212 // offset.
213 static error_code resolveSymbolName(const std::vector<RelocationRef> &Rels,
214                                     uint64_t Offset, StringRef &Name) {
215   SymbolRef Sym;
216   if (error_code EC = resolveSymbol(Rels, Offset, Sym))
217     return EC;
218   if (error_code EC = Sym.getName(Name))
219     return EC;
220   return object_error::success;
221 }
222 
223 static void printCOFFSymbolAddress(llvm::raw_ostream &Out,
224                                    const std::vector<RelocationRef> &Rels,
225                                    uint64_t Offset, uint32_t Disp) {
226   StringRef Sym;
227   if (error_code EC = resolveSymbolName(Rels, Offset, Sym)) {
228     error(EC);
229     return ;
230   }
231   Out << Sym;
232   if (Disp > 0)
233     Out << format(" + 0x%04x", Disp);
234 }
235 
236 // Prints import tables. The import table is a table containing the list of
237 // DLL name and symbol names which will be linked by the loader.
238 static void printImportTables(const COFFObjectFile *Obj) {
239   import_directory_iterator I = Obj->import_directory_begin();
240   import_directory_iterator E = Obj->import_directory_end();
241   if (I == E)
242     return;
243   outs() << "The Import Tables:\n";
244   for (; I != E; I = ++I) {
245     const import_directory_table_entry *Dir;
246     StringRef Name;
247     if (I->getImportTableEntry(Dir)) return;
248     if (I->getName(Name)) return;
249 
250     outs() << format("  lookup %08x time %08x fwd %08x name %08x addr %08x\n\n",
251                      static_cast<uint32_t>(Dir->ImportLookupTableRVA),
252                      static_cast<uint32_t>(Dir->TimeDateStamp),
253                      static_cast<uint32_t>(Dir->ForwarderChain),
254                      static_cast<uint32_t>(Dir->NameRVA),
255                      static_cast<uint32_t>(Dir->ImportAddressTableRVA));
256     outs() << "    DLL Name: " << Name << "\n";
257     outs() << "    Hint/Ord  Name\n";
258     const import_lookup_table_entry32 *entry;
259     if (I->getImportLookupEntry(entry))
260       return;
261     for (; entry->data; ++entry) {
262       if (entry->isOrdinal()) {
263         outs() << format("      % 6d\n", entry->getOrdinal());
264         continue;
265       }
266       uint16_t Hint;
267       StringRef Name;
268       if (Obj->getHintName(entry->getHintNameRVA(), Hint, Name))
269         return;
270       outs() << format("      % 6d  ", Hint) << Name << "\n";
271     }
272     outs() << "\n";
273   }
274 }
275 
276 // Prints export tables. The export table is a table containing the list of
277 // exported symbol from the DLL.
278 static void printExportTable(const COFFObjectFile *Obj) {
279   outs() << "Export Table:\n";
280   export_directory_iterator I = Obj->export_directory_begin();
281   export_directory_iterator E = Obj->export_directory_end();
282   if (I == E)
283     return;
284   StringRef DllName;
285   uint32_t OrdinalBase;
286   if (I->getDllName(DllName))
287     return;
288   if (I->getOrdinalBase(OrdinalBase))
289     return;
290   outs() << " DLL name: " << DllName << "\n";
291   outs() << " Ordinal base: " << OrdinalBase << "\n";
292   outs() << " Ordinal      RVA  Name\n";
293   for (; I != E; I = ++I) {
294     uint32_t Ordinal;
295     if (I->getOrdinal(Ordinal))
296       return;
297     uint32_t RVA;
298     if (I->getExportRVA(RVA))
299       return;
300     outs() << format("    % 4d %# 8x", Ordinal, RVA);
301 
302     StringRef Name;
303     if (I->getSymbolName(Name))
304       continue;
305     if (!Name.empty())
306       outs() << "  " << Name;
307     outs() << "\n";
308   }
309 }
310 
311 void llvm::printCOFFUnwindInfo(const COFFObjectFile *Obj) {
312   const coff_file_header *Header;
313   if (error(Obj->getCOFFHeader(Header))) return;
314 
315   if (Header->Machine != COFF::IMAGE_FILE_MACHINE_AMD64) {
316     errs() << "Unsupported image machine type "
317               "(currently only AMD64 is supported).\n";
318     return;
319   }
320 
321   const coff_section *Pdata = 0;
322 
323   for (section_iterator SI = Obj->section_begin(), SE = Obj->section_end();
324        SI != SE; ++SI) {
325     StringRef Name;
326     if (error(SI->getName(Name))) continue;
327 
328     if (Name != ".pdata") continue;
329 
330     Pdata = Obj->getCOFFSection(SI);
331     std::vector<RelocationRef> Rels;
332     for (relocation_iterator RI = SI->relocation_begin(),
333                              RE = SI->relocation_end();
334          RI != RE; ++RI)
335       Rels.push_back(*RI);
336 
337     // Sort relocations by address.
338     std::sort(Rels.begin(), Rels.end(), RelocAddressLess);
339 
340     ArrayRef<uint8_t> Contents;
341     if (error(Obj->getSectionContents(Pdata, Contents))) continue;
342     if (Contents.empty()) continue;
343 
344     ArrayRef<RuntimeFunction> RFs(
345                   reinterpret_cast<const RuntimeFunction *>(Contents.data()),
346                                   Contents.size() / sizeof(RuntimeFunction));
347     for (const RuntimeFunction *I = RFs.begin(), *E = RFs.end(); I < E; ++I) {
348       const uint64_t SectionOffset = std::distance(RFs.begin(), I)
349                                      * sizeof(RuntimeFunction);
350 
351       outs() << "Function Table:\n";
352 
353       outs() << "  Start Address: ";
354       printCOFFSymbolAddress(outs(), Rels, SectionOffset +
355                              /*offsetof(RuntimeFunction, StartAddress)*/ 0,
356                              I->StartAddress);
357       outs() << "\n";
358 
359       outs() << "  End Address: ";
360       printCOFFSymbolAddress(outs(), Rels, SectionOffset +
361                              /*offsetof(RuntimeFunction, EndAddress)*/ 4,
362                              I->EndAddress);
363       outs() << "\n";
364 
365       outs() << "  Unwind Info Address: ";
366       printCOFFSymbolAddress(outs(), Rels, SectionOffset +
367                              /*offsetof(RuntimeFunction, UnwindInfoOffset)*/ 8,
368                              I->UnwindInfoOffset);
369       outs() << "\n";
370 
371       ArrayRef<uint8_t> XContents;
372       uint64_t UnwindInfoOffset = 0;
373       if (error(getSectionContents(Obj, Rels, SectionOffset +
374                               /*offsetof(RuntimeFunction, UnwindInfoOffset)*/ 8,
375                                    XContents, UnwindInfoOffset))) continue;
376       if (XContents.empty()) continue;
377 
378       UnwindInfoOffset += I->UnwindInfoOffset;
379       if (UnwindInfoOffset > XContents.size()) continue;
380 
381       const Win64EH::UnwindInfo *UI =
382                             reinterpret_cast<const Win64EH::UnwindInfo *>
383                               (XContents.data() + UnwindInfoOffset);
384 
385       // The casts to int are required in order to output the value as number.
386       // Without the casts the value would be interpreted as char data (which
387       // results in garbage output).
388       outs() << "  Version: " << static_cast<int>(UI->getVersion()) << "\n";
389       outs() << "  Flags: " << static_cast<int>(UI->getFlags());
390       if (UI->getFlags()) {
391           if (UI->getFlags() & UNW_ExceptionHandler)
392             outs() << " UNW_ExceptionHandler";
393           if (UI->getFlags() & UNW_TerminateHandler)
394             outs() << " UNW_TerminateHandler";
395           if (UI->getFlags() & UNW_ChainInfo)
396             outs() << " UNW_ChainInfo";
397       }
398       outs() << "\n";
399       outs() << "  Size of prolog: "
400              << static_cast<int>(UI->PrologSize) << "\n";
401       outs() << "  Number of Codes: "
402              << static_cast<int>(UI->NumCodes) << "\n";
403       // Maybe this should move to output of UOP_SetFPReg?
404       if (UI->getFrameRegister()) {
405         outs() << "  Frame register: "
406                 << getUnwindRegisterName(UI->getFrameRegister())
407                 << "\n";
408         outs() << "  Frame offset: "
409                 << 16 * UI->getFrameOffset()
410                 << "\n";
411       } else {
412         outs() << "  No frame pointer used\n";
413       }
414       if (UI->getFlags() & (UNW_ExceptionHandler | UNW_TerminateHandler)) {
415         // FIXME: Output exception handler data
416       } else if (UI->getFlags() & UNW_ChainInfo) {
417         // FIXME: Output chained unwind info
418       }
419 
420       if (UI->NumCodes)
421         outs() << "  Unwind Codes:\n";
422 
423       printAllUnwindCodes(ArrayRef<UnwindCode>(&UI->UnwindCodes[0],
424                           UI->NumCodes));
425 
426       outs() << "\n\n";
427       outs().flush();
428     }
429   }
430 }
431 
432 void llvm::printCOFFFileHeader(const object::ObjectFile *Obj) {
433   const COFFObjectFile *file = dyn_cast<const COFFObjectFile>(Obj);
434   printImportTables(file);
435   printExportTable(file);
436 }
437