1 //===- Win64EHDumper.cpp - Win64 EH Printer ---------------------*- 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 #include "Win64EHDumper.h"
11 #include "llvm-readobj.h"
12 #include "llvm/Object/COFF.h"
13 #include "llvm/Support/ErrorHandling.h"
14 #include "llvm/Support/Format.h"
15 
16 using namespace llvm;
17 using namespace llvm::object;
18 using namespace llvm::Win64EH;
19 
20 static const EnumEntry<unsigned> UnwindFlags[] = {
21   { "ExceptionHandler", UNW_ExceptionHandler },
22   { "TerminateHandler", UNW_TerminateHandler },
23   { "ChainInfo"       , UNW_ChainInfo        }
24 };
25 
26 static const EnumEntry<unsigned> UnwindOpInfo[] = {
27   { "RAX",  0 },
28   { "RCX",  1 },
29   { "RDX",  2 },
30   { "RBX",  3 },
31   { "RSP",  4 },
32   { "RBP",  5 },
33   { "RSI",  6 },
34   { "RDI",  7 },
35   { "R8",   8 },
36   { "R9",   9 },
37   { "R10", 10 },
38   { "R11", 11 },
39   { "R12", 12 },
40   { "R13", 13 },
41   { "R14", 14 },
42   { "R15", 15 }
43 };
44 
45 static uint64_t getOffsetOfLSDA(const UnwindInfo& UI) {
46   return static_cast<const char*>(UI.getLanguageSpecificData())
47          - reinterpret_cast<const char*>(&UI);
48 }
49 
50 static uint32_t getLargeSlotValue(ArrayRef<UnwindCode> UC) {
51   if (UC.size() < 3)
52     return 0;
53   return UC[1].FrameOffset + (static_cast<uint32_t>(UC[2].FrameOffset) << 16);
54 }
55 
56 // Returns the name of the unwind code.
57 static StringRef getUnwindCodeTypeName(uint8_t Code) {
58   switch (Code) {
59   default: llvm_unreachable("Invalid unwind code");
60   case UOP_PushNonVol: return "PUSH_NONVOL";
61   case UOP_AllocLarge: return "ALLOC_LARGE";
62   case UOP_AllocSmall: return "ALLOC_SMALL";
63   case UOP_SetFPReg: return "SET_FPREG";
64   case UOP_SaveNonVol: return "SAVE_NONVOL";
65   case UOP_SaveNonVolBig: return "SAVE_NONVOL_FAR";
66   case UOP_SaveXMM128: return "SAVE_XMM128";
67   case UOP_SaveXMM128Big: return "SAVE_XMM128_FAR";
68   case UOP_PushMachFrame: return "PUSH_MACHFRAME";
69   }
70 }
71 
72 // Returns the name of a referenced register.
73 static StringRef getUnwindRegisterName(uint8_t Reg) {
74   switch (Reg) {
75   default: llvm_unreachable("Invalid register");
76   case 0: return "RAX";
77   case 1: return "RCX";
78   case 2: return "RDX";
79   case 3: return "RBX";
80   case 4: return "RSP";
81   case 5: return "RBP";
82   case 6: return "RSI";
83   case 7: return "RDI";
84   case 8: return "R8";
85   case 9: return "R9";
86   case 10: return "R10";
87   case 11: return "R11";
88   case 12: return "R12";
89   case 13: return "R13";
90   case 14: return "R14";
91   case 15: return "R15";
92   }
93 }
94 
95 // Calculates the number of array slots required for the unwind code.
96 static unsigned getNumUsedSlots(const UnwindCode &UnwindCode) {
97   switch (UnwindCode.getUnwindOp()) {
98   default: llvm_unreachable("Invalid unwind code");
99   case UOP_PushNonVol:
100   case UOP_AllocSmall:
101   case UOP_SetFPReg:
102   case UOP_PushMachFrame:
103     return 1;
104   case UOP_SaveNonVol:
105   case UOP_SaveXMM128:
106     return 2;
107   case UOP_SaveNonVolBig:
108   case UOP_SaveXMM128Big:
109     return 3;
110   case UOP_AllocLarge:
111     return (UnwindCode.getOpInfo() == 0) ? 2 : 3;
112   }
113 }
114 
115 static std::string formatSymbol(const Dumper::Context &Ctx,
116                                 const coff_section *Section, uint64_t Offset,
117                                 uint32_t Displacement) {
118   std::string Buffer;
119   raw_string_ostream OS(Buffer);
120 
121   SymbolRef Symbol;
122   if (!Ctx.ResolveSymbol(Section, Offset, Symbol, Ctx.UserData)) {
123     if (ErrorOr<StringRef> Name = Symbol.getName()) {
124       OS << *Name;
125       if (Displacement > 0)
126         OS << format(" +0x%X (0x%" PRIX64 ")", Displacement, Offset);
127       else
128         OS << format(" (0x%" PRIX64 ")", Offset);
129       return OS.str();
130     }
131   }
132 
133   OS << format(" (0x%" PRIX64 ")", Offset);
134   return OS.str();
135 }
136 
137 static std::error_code resolveRelocation(const Dumper::Context &Ctx,
138                                          const coff_section *Section,
139                                          uint64_t Offset,
140                                          const coff_section *&ResolvedSection,
141                                          uint64_t &ResolvedAddress) {
142   SymbolRef Symbol;
143   if (std::error_code EC =
144           Ctx.ResolveSymbol(Section, Offset, Symbol, Ctx.UserData))
145     return EC;
146 
147   ErrorOr<uint64_t> ResolvedAddressOrErr = Symbol.getAddress();
148   if (std::error_code EC = ResolvedAddressOrErr.getError())
149     return EC;
150   ResolvedAddress = *ResolvedAddressOrErr;
151 
152   section_iterator SI = Ctx.COFF.section_begin();
153   if (std::error_code EC = Symbol.getSection(SI))
154     return EC;
155 
156   ResolvedSection = Ctx.COFF.getCOFFSection(*SI);
157   return std::error_code();
158 }
159 
160 namespace llvm {
161 namespace Win64EH {
162 void Dumper::printRuntimeFunctionEntry(const Context &Ctx,
163                                        const coff_section *Section,
164                                        uint64_t Offset,
165                                        const RuntimeFunction &RF) {
166   SW.printString("StartAddress",
167                  formatSymbol(Ctx, Section, Offset + 0, RF.StartAddress));
168   SW.printString("EndAddress",
169                  formatSymbol(Ctx, Section, Offset + 4, RF.EndAddress));
170   SW.printString("UnwindInfoAddress",
171                  formatSymbol(Ctx, Section, Offset + 8, RF.UnwindInfoOffset));
172 }
173 
174 // Prints one unwind code. Because an unwind code can occupy up to 3 slots in
175 // the unwind codes array, this function requires that the correct number of
176 // slots is provided.
177 void Dumper::printUnwindCode(const UnwindInfo& UI, ArrayRef<UnwindCode> UC) {
178   assert(UC.size() >= getNumUsedSlots(UC[0]));
179 
180   SW.startLine() << format("0x%02X: ", unsigned(UC[0].u.CodeOffset))
181                  << getUnwindCodeTypeName(UC[0].getUnwindOp());
182 
183   switch (UC[0].getUnwindOp()) {
184   case UOP_PushNonVol:
185     OS << " reg=" << getUnwindRegisterName(UC[0].getOpInfo());
186     break;
187 
188   case UOP_AllocLarge:
189     OS << " size="
190        << ((UC[0].getOpInfo() == 0) ? UC[1].FrameOffset * 8
191                                     : getLargeSlotValue(UC));
192     break;
193 
194   case UOP_AllocSmall:
195     OS << " size=" << (UC[0].getOpInfo() + 1) * 8;
196     break;
197 
198   case UOP_SetFPReg:
199     if (UI.getFrameRegister() == 0)
200       OS << " reg=<invalid>";
201     else
202       OS << " reg=" << getUnwindRegisterName(UI.getFrameRegister())
203          << format(", offset=0x%X", UI.getFrameOffset() * 16);
204     break;
205 
206   case UOP_SaveNonVol:
207     OS << " reg=" << getUnwindRegisterName(UC[0].getOpInfo())
208        << format(", offset=0x%X", UC[1].FrameOffset * 8);
209     break;
210 
211   case UOP_SaveNonVolBig:
212     OS << " reg=" << getUnwindRegisterName(UC[0].getOpInfo())
213        << format(", offset=0x%X", getLargeSlotValue(UC));
214     break;
215 
216   case UOP_SaveXMM128:
217     OS << " reg=XMM" << static_cast<uint32_t>(UC[0].getOpInfo())
218        << format(", offset=0x%X", UC[1].FrameOffset * 16);
219     break;
220 
221   case UOP_SaveXMM128Big:
222     OS << " reg=XMM" << static_cast<uint32_t>(UC[0].getOpInfo())
223        << format(", offset=0x%X", getLargeSlotValue(UC));
224     break;
225 
226   case UOP_PushMachFrame:
227     OS << " errcode=" << (UC[0].getOpInfo() == 0 ? "no" : "yes");
228     break;
229   }
230 
231   OS << "\n";
232 }
233 
234 void Dumper::printUnwindInfo(const Context &Ctx, const coff_section *Section,
235                              off_t Offset, const UnwindInfo &UI) {
236   DictScope UIS(SW, "UnwindInfo");
237   SW.printNumber("Version", UI.getVersion());
238   SW.printFlags("Flags", UI.getFlags(), makeArrayRef(UnwindFlags));
239   SW.printNumber("PrologSize", UI.PrologSize);
240   if (UI.getFrameRegister()) {
241     SW.printEnum("FrameRegister", UI.getFrameRegister(),
242                  makeArrayRef(UnwindOpInfo));
243     SW.printHex("FrameOffset", UI.getFrameOffset());
244   } else {
245     SW.printString("FrameRegister", StringRef("-"));
246     SW.printString("FrameOffset", StringRef("-"));
247   }
248 
249   SW.printNumber("UnwindCodeCount", UI.NumCodes);
250   {
251     ListScope UCS(SW, "UnwindCodes");
252     ArrayRef<UnwindCode> UC(&UI.UnwindCodes[0], UI.NumCodes);
253     for (const UnwindCode *UCI = UC.begin(), *UCE = UC.end(); UCI < UCE; ++UCI) {
254       unsigned UsedSlots = getNumUsedSlots(*UCI);
255       if (UsedSlots > UC.size()) {
256         errs() << "corrupt unwind data";
257         return;
258       }
259 
260       printUnwindCode(UI, ArrayRef<UnwindCode>(UCI, UCE));
261       UCI = UCI + UsedSlots - 1;
262     }
263   }
264 
265   uint64_t LSDAOffset = Offset + getOffsetOfLSDA(UI);
266   if (UI.getFlags() & (UNW_ExceptionHandler | UNW_TerminateHandler)) {
267     SW.printString("Handler",
268                    formatSymbol(Ctx, Section, LSDAOffset,
269                                 UI.getLanguageSpecificHandlerOffset()));
270   } else if (UI.getFlags() & UNW_ChainInfo) {
271     if (const RuntimeFunction *Chained = UI.getChainedFunctionEntry()) {
272       DictScope CS(SW, "Chained");
273       printRuntimeFunctionEntry(Ctx, Section, LSDAOffset, *Chained);
274     }
275   }
276 }
277 
278 void Dumper::printRuntimeFunction(const Context &Ctx,
279                                   const coff_section *Section,
280                                   uint64_t SectionOffset,
281                                   const RuntimeFunction &RF) {
282   DictScope RFS(SW, "RuntimeFunction");
283   printRuntimeFunctionEntry(Ctx, Section, SectionOffset, RF);
284 
285   const coff_section *XData;
286   uint64_t Offset;
287   if (error(resolveRelocation(Ctx, Section, SectionOffset + 8, XData, Offset)))
288     return;
289 
290   ArrayRef<uint8_t> Contents;
291   if (error(Ctx.COFF.getSectionContents(XData, Contents)) || Contents.empty())
292     return;
293 
294   Offset = Offset + RF.UnwindInfoOffset;
295   if (Offset > Contents.size())
296     return;
297 
298   const auto UI = reinterpret_cast<const UnwindInfo*>(Contents.data() + Offset);
299   printUnwindInfo(Ctx, XData, Offset, *UI);
300 }
301 
302 void Dumper::printData(const Context &Ctx) {
303   for (const auto &Section : Ctx.COFF.sections()) {
304     StringRef Name;
305     if (error(Section.getName(Name)))
306       continue;
307 
308     if (Name != ".pdata" && !Name.startswith(".pdata$"))
309       continue;
310 
311     const coff_section *PData = Ctx.COFF.getCOFFSection(Section);
312     ArrayRef<uint8_t> Contents;
313     if (error(Ctx.COFF.getSectionContents(PData, Contents)) || Contents.empty())
314       continue;
315 
316     const RuntimeFunction *Entries =
317       reinterpret_cast<const RuntimeFunction *>(Contents.data());
318     const size_t Count = Contents.size() / sizeof(RuntimeFunction);
319     ArrayRef<RuntimeFunction> RuntimeFunctions(Entries, Count);
320 
321     size_t Index = 0;
322     for (const auto &RF : RuntimeFunctions) {
323       printRuntimeFunction(Ctx, Ctx.COFF.getCOFFSection(Section),
324                            Index * sizeof(RuntimeFunction), RF);
325       ++Index;
326     }
327   }
328 }
329 }
330 }
331 
332