1 //===-- ArmUnwindInfo.cpp ---------------------------------------*- C++ -*-===//
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 //===----------------------------------------------------------------------===//
12 #include "Utility/ARM_DWARF_Registers.h"
13 #include "lldb/Core/Module.h"
14 #include "lldb/Core/Section.h"
15 #include "lldb/Symbol/ArmUnwindInfo.h"
16 #include "lldb/Symbol/SymbolVendor.h"
17 #include "lldb/Symbol/UnwindPlan.h"
18 #include "lldb/Utility/Endian.h"
21 * Unwind information reader and parser for the ARM exception handling ABI
23 * Implemented based on:
24 * Exception Handling ABI for the ARM Architecture
25 * Document number: ARM IHI 0038A (current through ABI r2.09)
26 * Date of Issue: 25th January 2007, reissued 30th November 2012
27 * http://infocenter.arm.com/help/topic/com.arm.doc.ihi0038a/IHI0038A_ehabi.pdf
31 using namespace lldb_private;
33 // Converts a prel31 avlue to lldb::addr_t with sign extension
34 static addr_t Prel31ToAddr(uint32_t prel31) {
36 if (prel31 & (1 << 30))
37 res |= 0xffffffff80000000ULL;
41 ArmUnwindInfo::ArmExidxEntry::ArmExidxEntry(uint32_t f, lldb::addr_t a,
43 : file_address(f), address(a), data(d) {}
45 bool ArmUnwindInfo::ArmExidxEntry::operator<(const ArmExidxEntry &other) const {
46 return address < other.address;
49 ArmUnwindInfo::ArmUnwindInfo(ObjectFile &objfile, SectionSP &arm_exidx,
51 : m_byte_order(objfile.GetByteOrder()), m_arm_exidx_sp(arm_exidx),
52 m_arm_extab_sp(arm_extab) {
53 objfile.ReadSectionData(arm_exidx.get(), m_arm_exidx_data);
54 objfile.ReadSectionData(arm_extab.get(), m_arm_extab_data);
56 addr_t exidx_base_addr = m_arm_exidx_sp->GetFileAddress();
59 while (m_arm_exidx_data.ValidOffset(offset)) {
60 lldb::addr_t file_addr = exidx_base_addr + offset;
61 lldb::addr_t addr = exidx_base_addr + (addr_t)offset +
62 Prel31ToAddr(m_arm_exidx_data.GetU32(&offset));
63 uint32_t data = m_arm_exidx_data.GetU32(&offset);
64 m_exidx_entries.emplace_back(file_addr, addr, data);
67 // Sort the entries in the exidx section. The entries should be sorted inside
69 // some old compiler isn't sorted them.
70 std::sort(m_exidx_entries.begin(), m_exidx_entries.end());
73 ArmUnwindInfo::~ArmUnwindInfo() {}
75 // Read a byte from the unwind instruction stream with the given offset.
76 // Custom function is required because have to red in order of significance
77 // within their containing
78 // word (most significant byte first) and in increasing word address order.
79 uint8_t ArmUnwindInfo::GetByteAtOffset(const uint32_t *data,
80 uint16_t offset) const {
81 uint32_t value = data[offset / 4];
82 if (m_byte_order != endian::InlHostByteOrder())
83 value = llvm::ByteSwap_32(value);
84 return (value >> ((3 - (offset % 4)) * 8)) & 0xff;
87 uint64_t ArmUnwindInfo::GetULEB128(const uint32_t *data, uint16_t &offset,
88 uint16_t max_offset) const {
91 while (offset < max_offset) {
92 uint8_t byte = GetByteAtOffset(data, offset++);
93 result |= (uint64_t)(byte & 0x7f) << shift;
94 if ((byte & 0x80) == 0)
101 bool ArmUnwindInfo::GetUnwindPlan(Target &target, const Address &addr,
102 UnwindPlan &unwind_plan) {
103 const uint32_t *data = (const uint32_t *)GetExceptionHandlingTableEntry(addr);
105 return false; // No unwind information for the function
108 return false; // EXIDX_CANTUNWIND
110 uint16_t byte_count = 0;
111 uint16_t byte_offset = 0;
112 if (data[0] & 0x80000000) {
113 switch ((data[0] >> 24) & 0x0f) {
120 byte_count = 4 * ((data[0] >> 16) & 0xff) + 4;
124 // Unhandled personality routine index
128 byte_count = 4 * ((data[1] >> 24) & 0xff) + 8;
132 uint8_t vsp_reg = dwarf_sp;
134 std::vector<std::pair<uint32_t, int32_t>>
135 register_offsets; // register -> (offset from vsp_reg)
137 while (byte_offset < byte_count) {
138 uint8_t byte1 = GetByteAtOffset(data, byte_offset++);
139 if ((byte1 & 0xc0) == 0x00) {
141 // vsp = vsp + (xxxxxx << 2) + 4. Covers range 0x04-0x100 inclusive
142 vsp += ((byte1 & 0x3f) << 2) + 4;
143 } else if ((byte1 & 0xc0) == 0x40) {
145 // vsp = vsp – (xxxxxx << 2) - 4. Covers range 0x04-0x100 inclusive
146 vsp -= ((byte1 & 0x3f) << 2) + 4;
147 } else if ((byte1 & 0xf0) == 0x80) {
148 if (byte_offset >= byte_count)
151 uint8_t byte2 = GetByteAtOffset(data, byte_offset++);
152 if (byte1 == 0x80 && byte2 == 0) {
154 // Refuse to unwind (for example, out of a cleanup) (see remark a)
157 // 1000iiii iiiiiiii (i not all 0)
158 // Pop up to 12 integer registers under masks {r15-r12}, {r11-r4} (see
160 uint16_t regs = ((byte1 & 0x0f) << 8) | byte2;
161 for (uint8_t i = 0; i < 12; ++i) {
162 if (regs & (1 << i)) {
163 register_offsets.emplace_back(dwarf_r4 + i, vsp);
168 } else if ((byte1 & 0xff) == 0x9d) {
170 // Reserved as prefix for ARM register to register moves
172 } else if ((byte1 & 0xff) == 0x9f) {
174 // Reserved as prefix for Intel Wireless MMX register to register moves
176 } else if ((byte1 & 0xf0) == 0x90) {
177 // 1001nnnn (nnnn != 13,15)
179 vsp_reg = dwarf_r0 + (byte1 & 0x0f);
180 } else if ((byte1 & 0xf8) == 0xa0) {
183 uint8_t n = byte1 & 0x7;
184 for (uint8_t i = 0; i <= n; ++i) {
185 register_offsets.emplace_back(dwarf_r4 + i, vsp);
188 } else if ((byte1 & 0xf8) == 0xa8) {
190 // Pop r4-r[4+nnn], r14
191 uint8_t n = byte1 & 0x7;
192 for (uint8_t i = 0; i <= n; ++i) {
193 register_offsets.emplace_back(dwarf_r4 + i, vsp);
197 register_offsets.emplace_back(dwarf_lr, vsp);
199 } else if ((byte1 & 0xff) == 0xb0) {
201 // Finish (see remark c)
203 } else if ((byte1 & 0xff) == 0xb1) {
204 if (byte_offset >= byte_count)
207 uint8_t byte2 = GetByteAtOffset(data, byte_offset++);
208 if ((byte2 & 0xff) == 0x00) {
210 // Spare (see remark f)
212 } else if ((byte2 & 0xf0) == 0x00) {
213 // 10110001 0000iiii (i not all 0)
214 // Pop integer registers under mask {r3, r2, r1, r0}
215 for (uint8_t i = 0; i < 4; ++i) {
216 if (byte2 & (1 << i)) {
217 register_offsets.emplace_back(dwarf_r0 + i, vsp);
223 // Spare (xxxx != 0000)
226 } else if ((byte1 & 0xff) == 0xb2) {
228 // vsp = vsp + 0x204+ (uleb128 << 2)
229 uint64_t uleb128 = GetULEB128(data, byte_offset, byte_count);
230 vsp += 0x204 + (uleb128 << 2);
231 } else if ((byte1 & 0xff) == 0xb3) {
233 // Pop VFP double-precision registers D[ssss]-D[ssss+cccc] saved (as if)
234 // by FSTMFDX (see remark d)
235 if (byte_offset >= byte_count)
238 uint8_t byte2 = GetByteAtOffset(data, byte_offset++);
239 uint8_t s = (byte2 & 0xf0) >> 4;
240 uint8_t c = (byte2 & 0x0f) >> 0;
241 for (uint8_t i = 0; i <= c; ++i) {
242 register_offsets.emplace_back(dwarf_d0 + s + i, vsp);
246 } else if ((byte1 & 0xfc) == 0xb4) {
248 // Spare (was Pop FPA)
250 } else if ((byte1 & 0xf8) == 0xb8) {
252 // Pop VFP double-precision registers D[8]-D[8+nnn] saved (as if) by
253 // FSTMFDX (see remark d)
254 uint8_t n = byte1 & 0x07;
255 for (uint8_t i = 0; i <= n; ++i) {
256 register_offsets.emplace_back(dwarf_d8 + i, vsp);
260 } else if ((byte1 & 0xf8) == 0xc0) {
261 // 11000nnn (nnn != 6,7)
262 // Intel Wireless MMX pop wR[10]-wR[10+nnn]
265 // Intel Wireless MMX pop wR[ssss]-wR[ssss+cccc] (see remark e)
271 // Intel Wireless MMX pop wCGR registers under mask {wCGR3,2,1,0}
274 // Spare (xxxx != 0000)
277 } else if ((byte1 & 0xff) == 0xc8) {
279 // Pop VFP double precision registers D[16+ssss]-D[16+ssss+cccc] saved (as
280 // if) by FSTMFDD (see remarks d,e)
281 if (byte_offset >= byte_count)
284 uint8_t byte2 = GetByteAtOffset(data, byte_offset++);
285 uint8_t s = (byte2 & 0xf0) >> 4;
286 uint8_t c = (byte2 & 0x0f) >> 0;
287 for (uint8_t i = 0; i <= c; ++i) {
288 register_offsets.emplace_back(dwarf_d16 + s + i, vsp);
291 } else if ((byte1 & 0xff) == 0xc9) {
293 // Pop VFP double precision registers D[ssss]-D[ssss+cccc] saved (as if)
294 // by FSTMFDD (see remark d)
295 if (byte_offset >= byte_count)
298 uint8_t byte2 = GetByteAtOffset(data, byte_offset++);
299 uint8_t s = (byte2 & 0xf0) >> 4;
300 uint8_t c = (byte2 & 0x0f) >> 0;
301 for (uint8_t i = 0; i <= c; ++i) {
302 register_offsets.emplace_back(dwarf_d0 + s + i, vsp);
305 } else if ((byte1 & 0xf8) == 0xc8) {
307 // Spare (yyy != 000, 001)
309 } else if ((byte1 & 0xf8) == 0xc0) {
311 // Pop VFP double-precision registers D[8]-D[8+nnn] saved (as if) by
312 // FSTMFDD (see remark d)
313 uint8_t n = byte1 & 0x07;
314 for (uint8_t i = 0; i <= n; ++i) {
315 register_offsets.emplace_back(dwarf_d8 + i, vsp);
318 } else if ((byte1 & 0xc0) == 0xc0) {
319 // 11xxxyyy Spare (xxx != 000, 001, 010)
326 UnwindPlan::RowSP row = std::make_shared<UnwindPlan::Row>();
328 row->GetCFAValue().SetIsRegisterPlusOffset(vsp_reg, vsp);
330 bool have_location_for_pc = false;
331 for (const auto &offset : register_offsets) {
332 have_location_for_pc |= offset.first == dwarf_pc;
333 row->SetRegisterLocationToAtCFAPlusOffset(offset.first, offset.second - vsp,
337 if (!have_location_for_pc) {
338 UnwindPlan::Row::RegisterLocation lr_location;
339 if (row->GetRegisterInfo(dwarf_lr, lr_location))
340 row->SetRegisterInfo(dwarf_pc, lr_location);
342 row->SetRegisterLocationToRegister(dwarf_pc, dwarf_lr, false);
345 unwind_plan.AppendRow(row);
346 unwind_plan.SetSourceName("ARM.exidx unwind info");
347 unwind_plan.SetSourcedFromCompiler(eLazyBoolYes);
348 unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
349 unwind_plan.SetRegisterKind(eRegisterKindDWARF);
355 ArmUnwindInfo::GetExceptionHandlingTableEntry(const Address &addr) {
356 auto it = std::upper_bound(m_exidx_entries.begin(), m_exidx_entries.end(),
357 ArmExidxEntry{0, addr.GetFileAddress(), 0});
358 if (it == m_exidx_entries.begin())
363 return nullptr; // EXIDX_CANTUNWIND
365 if (it->data & 0x80000000)
366 return (const uint8_t *)&it->data;
368 addr_t data_file_addr = it->file_address + 4 + Prel31ToAddr(it->data);
369 return m_arm_extab_data.GetDataStart() +
370 (data_file_addr - m_arm_extab_sp->GetFileAddress());