1 //===--- ARMEHABIPrinter.h - ARM EHABI Unwind Information Printer ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef LLVM_READOBJ_ARMEHABI_PRINTER_H
11 #define LLVM_READOBJ_ARMEHABI_PRINTER_H
13 #include "StreamWriter.h"
14 #include "llvm/Object/ELF.h"
15 #include "llvm/Object/ELFTypes.h"
16 #include "llvm/Support/ARMEHABI.h"
17 #include "llvm/Support/Endian.h"
18 #include "llvm/Support/type_traits.h"
23 template <typename ET>
24 class PrinterContext {
26 const object::ELFFile<ET> *ELF;
28 typedef typename object::ELFFile<ET>::Elf_Sym Elf_Sym;
29 typedef typename object::ELFFile<ET>::Elf_Shdr Elf_Shdr;
31 typedef typename object::ELFFile<ET>::Elf_Rel_Iter Elf_Rel_iterator;
32 typedef typename object::ELFFile<ET>::Elf_Sym_Iter Elf_Sym_iterator;
33 typedef typename object::ELFFile<ET>::Elf_Shdr_Iter Elf_Shdr_iterator;
35 static const size_t IndexTableEntrySize;
37 static uint64_t PREL31(uint32_t Address, uint32_t Place) {
38 uint64_t Location = Address & 0x7fffffff;
39 if (Location & 0x04000000)
40 Location |= (uint64_t) ~0x7fffffff;
41 return Location + Place;
44 ErrorOr<StringRef> FunctionAtAddress(unsigned Section, uint64_t Address) const;
45 const Elf_Shdr *FindExceptionTable(unsigned IndexTableIndex,
46 off_t IndexTableOffset) const;
48 void PrintIndexTable(unsigned SectionIndex, const Elf_Shdr *IT) const;
49 void PrintExceptionTable(const Elf_Shdr *IT, const Elf_Shdr *EHT,
50 uint64_t TableEntryOffset) const;
51 void PrintOpcodes(const uint8_t *Entry, size_t Length, off_t Offset) const;
54 PrinterContext(StreamWriter &Writer, const object::ELFFile<ET> *File)
55 : SW(Writer), ELF(File) {}
57 void PrintUnwindInformation() const;
60 template <typename ET>
61 const size_t PrinterContext<ET>::IndexTableEntrySize = 8;
63 template <typename ET>
64 ErrorOr<StringRef> PrinterContext<ET>::FunctionAtAddress(unsigned Section,
65 uint64_t Address) const {
66 for (Elf_Sym_iterator SI = ELF->begin_symbols(), SE = ELF->end_symbols();
68 if (SI->st_shndx == Section && SI->st_value == Address &&
69 SI->getType() == ELF::STT_FUNC)
70 return ELF->getSymbolName(SI);
71 return readobj_error::unknown_symbol;
74 template <typename ET>
75 const typename object::ELFFile<ET>::Elf_Shdr *
76 PrinterContext<ET>::FindExceptionTable(unsigned IndexSectionIndex,
77 off_t IndexTableOffset) const {
78 /// Iterate through the sections, searching for the relocation section
79 /// associated with the unwind index table section specified by
80 /// IndexSectionIndex. Iterate the associated section searching for the
81 /// relocation associated with the index table entry specified by
82 /// IndexTableOffset. The symbol is the section symbol for the exception
83 /// handling table. Use this symbol to recover the actual exception handling
86 for (Elf_Shdr_iterator SI = ELF->begin_sections(), SE = ELF->end_sections();
88 if (SI->sh_type == ELF::SHT_REL && SI->sh_info == IndexSectionIndex) {
89 for (Elf_Rel_iterator RI = ELF->begin_rel(&*SI), RE = ELF->end_rel(&*SI);
91 if (RI->r_offset == IndexTableOffset) {
92 typename object::ELFFile<ET>::Elf_Rela RelA;
93 RelA.r_offset = RI->r_offset;
94 RelA.r_info = RI->r_info;
97 std::pair<const Elf_Shdr *, const Elf_Sym *> Symbol =
98 ELF->getRelocationSymbol(&(*SI), &RelA);
100 return ELF->getSection(Symbol.second);
108 template <typename ET>
109 void PrinterContext<ET>::PrintExceptionTable(const Elf_Shdr *IT,
111 uint64_t TableEntryOffset) const {
112 ErrorOr<ArrayRef<uint8_t> > Contents = ELF->getSectionContents(EHT);
116 /// ARM EHABI Section 6.2 - The generic model
118 /// An exception-handling table entry for the generic model is laid out as:
122 /// +-+------------------------------+
123 /// |0| personality routine offset |
124 /// +-+------------------------------+
125 /// | personality routine data ... |
128 /// ARM EHABI Section 6.3 - The ARM-defined compact model
130 /// An exception-handling table entry for the compact model looks like:
134 /// +-+---+----+-----------------------+
135 /// |1| 0 | Ix | data for pers routine |
136 /// +-+---+----+-----------------------+
137 /// | more personality routine data |
139 const support::ulittle32_t Word =
140 *reinterpret_cast<const support::ulittle32_t *>(Contents->data() + TableEntryOffset);
142 if (Word & 0x80000000) {
143 SW.printString("Model", StringRef("Compact"));
145 unsigned PersonalityIndex = (Word & 0x0f000000) >> 24;
146 SW.printNumber("PersonalityIndex", PersonalityIndex);
148 switch (PersonalityIndex) {
149 case AEABI_UNWIND_CPP_PR0:
150 llvm_unreachable("Personality 0 should be compact inline!");
152 case AEABI_UNWIND_CPP_PR1:
153 case AEABI_UNWIND_CPP_PR2:
154 unsigned AdditionalWords = (Word & 0x00ff0000) >> 16;
155 PrintOpcodes(Contents->data() + TableEntryOffset, 2 + 4 * AdditionalWords,
160 SW.printString("Model", StringRef("Generic"));
162 uint64_t Address = PREL31(Word, EHT->sh_addr);
163 SW.printHex("PersonalityRoutineAddress", Address);
164 if (ErrorOr<StringRef> Name = FunctionAtAddress(EHT->sh_link, Address))
165 SW.printString("PersonalityRoutineName", *Name);
169 template <typename ET>
170 void PrinterContext<ET>::PrintOpcodes(const uint8_t *Entry,
171 size_t Length, off_t Offset) const {
172 ListScope OCC(SW, "Opcodes");
173 for (unsigned OCI = Offset; OCI < Length + Offset; OCI++)
174 SW.printHex("Opcode", Entry[OCI ^ 0x3]);
177 template <typename ET>
178 void PrinterContext<ET>::PrintIndexTable(unsigned SectionIndex,
179 const Elf_Shdr *IT) const {
180 ErrorOr<ArrayRef<uint8_t> > Contents = ELF->getSectionContents(IT);
184 /// ARM EHABI Section 5 - Index Table Entries
185 /// * The first word contains a PREL31 offset to the start of a function with
187 /// * The second word contains one of:
188 /// - The PREL31 offset of the start of the table entry for the function,
189 /// with bit 31 clear
190 /// - The exception-handling table entry itself with bit 31 set
191 /// - The special bit pattern EXIDX_CANTUNWIND, indicating that associated
192 /// frames cannot be unwound
194 const support::ulittle32_t *Data =
195 reinterpret_cast<const support::ulittle32_t *>(Contents->data());
196 const unsigned Entries = IT->sh_size / IndexTableEntrySize;
198 ListScope E(SW, "Entries");
199 for (unsigned Entry = 0; Entry < Entries; ++Entry) {
200 DictScope E(SW, "Entry");
202 const support::ulittle32_t Word0 =
203 Data[Entry * (IndexTableEntrySize / sizeof(*Data)) + 0];
204 const support::ulittle32_t Word1 =
205 Data[Entry * (IndexTableEntrySize / sizeof(*Data)) + 1];
207 if (Word0 & 0x80000000) {
208 errs() << "corrupt unwind data in section " << SectionIndex << "\n";
212 const uint64_t Offset = PREL31(Word0, IT->sh_addr);
213 SW.printHex("FunctionAddress", Offset);
214 if (ErrorOr<StringRef> Name = FunctionAtAddress(IT->sh_link, Offset))
215 SW.printString("FunctionName", *Name);
217 if (Word1 == EXIDX_CANTUNWIND) {
218 SW.printString("Model", StringRef("CantUnwind"));
222 if (Word1 & 0x80000000) {
223 SW.printString("Model", StringRef("Compact (Inline)"));
225 unsigned PersonalityIndex = (Word1 & 0x0f000000) >> 24;
226 SW.printNumber("PersonalityIndex", PersonalityIndex);
228 PrintOpcodes(Contents->data() + Entry * IndexTableEntrySize + 4, 3, 1);
230 const Elf_Shdr *EHT =
231 FindExceptionTable(SectionIndex, Entry * IndexTableEntrySize + 4);
233 if (ErrorOr<StringRef> Name = ELF->getSectionName(EHT))
234 SW.printString("ExceptionHandlingTable", *Name);
236 uint64_t TableEntryOffset = PREL31(Word1, IT->sh_addr);
237 SW.printHex("TableEntryOffset", TableEntryOffset);
239 PrintExceptionTable(IT, EHT, TableEntryOffset);
244 template <typename ET>
245 void PrinterContext<ET>::PrintUnwindInformation() const {
246 DictScope UI(SW, "UnwindInformation");
248 int SectionIndex = 0;
249 for (Elf_Shdr_iterator SI = ELF->begin_sections(), SE = ELF->end_sections();
250 SI != SE; ++SI, ++SectionIndex) {
251 if (SI->sh_type == ELF::SHT_ARM_EXIDX) {
252 const Elf_Shdr *IT = &(*SI);
254 DictScope UIT(SW, "UnwindIndexTable");
256 SW.printNumber("SectionIndex", SectionIndex);
257 if (ErrorOr<StringRef> SectionName = ELF->getSectionName(IT))
258 SW.printString("SectionName", *SectionName);
259 SW.printHex("SectionOffset", IT->sh_offset);
261 PrintIndexTable(SectionIndex, IT);