1//===-- ABISysV_i386.cpp --------------------------------------------------===//
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#include "ABISysV_i386.h"
9
10#include "llvm/ADT/STLExtras.h"
11#include "llvm/TargetParser/Triple.h"
12
13#include "lldb/Core/Module.h"
14#include "lldb/Core/PluginManager.h"
15#include "lldb/Core/Value.h"
16#include "lldb/Symbol/UnwindPlan.h"
17#include "lldb/Target/Process.h"
18#include "lldb/Target/RegisterContext.h"
19#include "lldb/Target/StackFrame.h"
20#include "lldb/Target/Target.h"
21#include "lldb/Target/Thread.h"
22#include "lldb/Utility/ConstString.h"
23#include "lldb/Utility/DataExtractor.h"
24#include "lldb/Utility/Log.h"
25#include "lldb/Utility/RegisterValue.h"
26#include "lldb/Utility/Status.h"
27#include "lldb/ValueObject/ValueObjectConstResult.h"
28#include "lldb/ValueObject/ValueObjectMemory.h"
29#include "lldb/ValueObject/ValueObjectRegister.h"
30#include <optional>
31
32using namespace lldb;
33using namespace lldb_private;
34
35LLDB_PLUGIN_DEFINE(ABISysV_i386)
36
37// This source file uses the following document as a reference:
38//====================================================================
39// System V Application Binary Interface
40// Intel386 Architecture Processor Supplement, Version 1.0
41// Edited by
42// H.J. Lu, David L Kreitzer, Milind Girkar, Zia Ansari
43//
44// (Based on
45// System V Application Binary Interface,
46// AMD64 Architecture Processor Supplement,
47// Edited by
48// H.J. Lu, Michael Matz, Milind Girkar, Jan Hubicka,
49// Andreas Jaeger, Mark Mitchell)
50//
51// February 3, 2015
52//====================================================================
53
54// DWARF Register Number Mapping
55// See Table 2.14 of the reference document (specified on top of this file)
56// Comment: Table 2.14 is followed till 'mm' entries. After that, all entries
57// are ignored here.
58
59enum dwarf_regnums {
60 dwarf_eax = 0,
61 dwarf_ecx,
62 dwarf_edx,
63 dwarf_ebx,
64 dwarf_esp,
65 dwarf_ebp,
66 dwarf_esi,
67 dwarf_edi,
68 dwarf_eip,
69};
70
71// Static Functions
72
73ABISP
74ABISysV_i386::CreateInstance(lldb::ProcessSP process_sp, const ArchSpec &arch) {
75 if (arch.GetTriple().getVendor() != llvm::Triple::Apple) {
76 if (arch.GetTriple().getArch() == llvm::Triple::x86) {
77 return ABISP(
78 new ABISysV_i386(std::move(process_sp), MakeMCRegisterInfo(arch)));
79 }
80 }
81 return ABISP();
82}
83
84bool ABISysV_i386::PrepareTrivialCall(Thread &thread, addr_t sp,
85 addr_t func_addr, addr_t return_addr,
86 llvm::ArrayRef<addr_t> args) const {
87 RegisterContext *reg_ctx = thread.GetRegisterContext().get();
88
89 if (!reg_ctx)
90 return false;
91
92 uint32_t pc_reg_num = reg_ctx->ConvertRegisterKindToRegisterNumber(
93 kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
94 uint32_t sp_reg_num = reg_ctx->ConvertRegisterKindToRegisterNumber(
95 kind: eRegisterKindGeneric, LLDB_REGNUM_GENERIC_SP);
96
97 // While using register info to write a register value to memory, the
98 // register info just needs to have the correct size of a 32 bit register,
99 // the actual register it pertains to is not important, just the size needs
100 // to be correct. "eax" is used here for this purpose.
101 const RegisterInfo *reg_info_32 = reg_ctx->GetRegisterInfoByName(reg_name: "eax");
102 if (!reg_info_32)
103 return false; // TODO this should actually never happen
104
105 Status error;
106 RegisterValue reg_value;
107
108 // Make room for the argument(s) on the stack
109 sp -= 4 * args.size();
110
111 // SP Alignment
112 sp &= ~(16ull - 1ull); // 16-byte alignment
113
114 // Write arguments onto the stack
115 addr_t arg_pos = sp;
116 for (addr_t arg : args) {
117 reg_value.SetUInt32(uint: arg);
118 error = reg_ctx->WriteRegisterValueToMemory(
119 reg_info: reg_info_32, dst_addr: arg_pos, dst_len: reg_info_32->byte_size, reg_value);
120 if (error.Fail())
121 return false;
122 arg_pos += 4;
123 }
124
125 // The return address is pushed onto the stack
126 sp -= 4;
127 reg_value.SetUInt32(uint: return_addr);
128 error = reg_ctx->WriteRegisterValueToMemory(
129 reg_info: reg_info_32, dst_addr: sp, dst_len: reg_info_32->byte_size, reg_value);
130 if (error.Fail())
131 return false;
132
133 // Setting %esp to the actual stack value.
134 if (!reg_ctx->WriteRegisterFromUnsigned(reg: sp_reg_num, uval: sp))
135 return false;
136
137 // Setting %eip to the address of the called function.
138 if (!reg_ctx->WriteRegisterFromUnsigned(reg: pc_reg_num, uval: func_addr))
139 return false;
140
141 return true;
142}
143
144static bool ReadIntegerArgument(Scalar &scalar, unsigned int bit_width,
145 bool is_signed, Process *process,
146 addr_t &current_stack_argument) {
147 uint32_t byte_size = (bit_width + (8 - 1)) / 8;
148 Status error;
149
150 if (!process)
151 return false;
152
153 if (process->ReadScalarIntegerFromMemory(addr: current_stack_argument, byte_size,
154 is_signed, scalar, error)) {
155 current_stack_argument += byte_size;
156 return true;
157 }
158 return false;
159}
160
161bool ABISysV_i386::GetArgumentValues(Thread &thread, ValueList &values) const {
162 unsigned int num_values = values.GetSize();
163 unsigned int value_index;
164
165 RegisterContext *reg_ctx = thread.GetRegisterContext().get();
166
167 if (!reg_ctx)
168 return false;
169
170 // Get pointer to the first stack argument
171 addr_t sp = reg_ctx->GetSP(fail_value: 0);
172 if (!sp)
173 return false;
174
175 addr_t current_stack_argument = sp + 4; // jump over return address
176
177 for (value_index = 0; value_index < num_values; ++value_index) {
178 Value *value = values.GetValueAtIndex(idx: value_index);
179
180 if (!value)
181 return false;
182
183 // Currently: Support for extracting values with Clang QualTypes only.
184 CompilerType compiler_type(value->GetCompilerType());
185 std::optional<uint64_t> bit_size =
186 llvm::expectedToOptional(E: compiler_type.GetBitSize(exe_scope: &thread));
187 if (bit_size) {
188 bool is_signed;
189 if (compiler_type.IsIntegerOrEnumerationType(is_signed)) {
190 ReadIntegerArgument(scalar&: value->GetScalar(), bit_width: *bit_size, is_signed,
191 process: thread.GetProcess().get(), current_stack_argument);
192 } else if (compiler_type.IsPointerType()) {
193 ReadIntegerArgument(scalar&: value->GetScalar(), bit_width: *bit_size, is_signed: false,
194 process: thread.GetProcess().get(), current_stack_argument);
195 }
196 }
197 }
198 return true;
199}
200
201Status ABISysV_i386::SetReturnValueObject(lldb::StackFrameSP &frame_sp,
202 lldb::ValueObjectSP &new_value_sp) {
203 Status error;
204 if (!new_value_sp) {
205 error = Status::FromErrorString(str: "Empty value object for return value.");
206 return error;
207 }
208
209 CompilerType compiler_type = new_value_sp->GetCompilerType();
210 if (!compiler_type) {
211 error = Status::FromErrorString(str: "Null clang type for return value.");
212 return error;
213 }
214
215 const uint32_t type_flags = compiler_type.GetTypeInfo();
216 Thread *thread = frame_sp->GetThread().get();
217 RegisterContext *reg_ctx = thread->GetRegisterContext().get();
218 DataExtractor data;
219 Status data_error;
220 size_t num_bytes = new_value_sp->GetData(data, error&: data_error);
221 bool register_write_successful = true;
222
223 if (data_error.Fail()) {
224 error = Status::FromErrorStringWithFormat(
225 format: "Couldn't convert return value to raw data: %s",
226 data_error.AsCString());
227 return error;
228 }
229
230 // Following "IF ELSE" block categorizes various 'Fundamental Data Types'.
231 // The terminology 'Fundamental Data Types' used here is adopted from Table
232 // 2.1 of the reference document (specified on top of this file)
233
234 if (type_flags & eTypeIsPointer) // 'Pointer'
235 {
236 if (num_bytes != sizeof(uint32_t)) {
237 error =
238 Status::FromErrorString(str: "Pointer to be returned is not 4 bytes wide");
239 return error;
240 }
241 lldb::offset_t offset = 0;
242 const RegisterInfo *eax_info = reg_ctx->GetRegisterInfoByName(reg_name: "eax", start_idx: 0);
243 uint32_t raw_value = data.GetMaxU32(offset_ptr: &offset, byte_size: num_bytes);
244 register_write_successful =
245 reg_ctx->WriteRegisterFromUnsigned(reg_info: eax_info, uval: raw_value);
246 } else if ((type_flags & eTypeIsScalar) ||
247 (type_flags & eTypeIsEnumeration)) //'Integral' + 'Floating Point'
248 {
249 lldb::offset_t offset = 0;
250 const RegisterInfo *eax_info = reg_ctx->GetRegisterInfoByName(reg_name: "eax", start_idx: 0);
251
252 if (type_flags & eTypeIsInteger) // 'Integral' except enum
253 {
254 switch (num_bytes) {
255 default:
256 break;
257 case 16:
258 // For clang::BuiltinType::UInt128 & Int128 ToDo: Need to decide how to
259 // handle it
260 break;
261 case 8: {
262 uint32_t raw_value_low = data.GetMaxU32(offset_ptr: &offset, byte_size: 4);
263 const RegisterInfo *edx_info = reg_ctx->GetRegisterInfoByName(reg_name: "edx", start_idx: 0);
264 uint32_t raw_value_high = data.GetMaxU32(offset_ptr: &offset, byte_size: num_bytes - offset);
265 register_write_successful =
266 (reg_ctx->WriteRegisterFromUnsigned(reg_info: eax_info, uval: raw_value_low) &&
267 reg_ctx->WriteRegisterFromUnsigned(reg_info: edx_info, uval: raw_value_high));
268 break;
269 }
270 case 4:
271 case 2:
272 case 1: {
273 uint32_t raw_value = data.GetMaxU32(offset_ptr: &offset, byte_size: num_bytes);
274 register_write_successful =
275 reg_ctx->WriteRegisterFromUnsigned(reg_info: eax_info, uval: raw_value);
276 break;
277 }
278 }
279 } else if (type_flags & eTypeIsEnumeration) // handles enum
280 {
281 uint32_t raw_value = data.GetMaxU32(offset_ptr: &offset, byte_size: num_bytes);
282 register_write_successful =
283 reg_ctx->WriteRegisterFromUnsigned(reg_info: eax_info, uval: raw_value);
284 } else if (type_flags & eTypeIsFloat) // 'Floating Point'
285 {
286 RegisterValue st0_value, fstat_value, ftag_value;
287 const RegisterInfo *st0_info = reg_ctx->GetRegisterInfoByName(reg_name: "st0", start_idx: 0);
288 const RegisterInfo *fstat_info =
289 reg_ctx->GetRegisterInfoByName(reg_name: "fstat", start_idx: 0);
290 const RegisterInfo *ftag_info = reg_ctx->GetRegisterInfoByName(reg_name: "ftag", start_idx: 0);
291
292 /* According to Page 3-12 of document
293 System V Application Binary Interface, Intel386 Architecture Processor
294 Supplement, Fourth Edition
295 To return Floating Point values, all st% registers except st0 should be
296 empty after exiting from
297 a function. This requires setting fstat and ftag registers to specific
298 values.
299 fstat: The TOP field of fstat should be set to a value [0,7]. ABI doesn't
300 specify the specific
301 value of TOP in case of function return. Hence, we set the TOP field to 7
302 by our choice. */
303 uint32_t value_fstat_u32 = 0x00003800;
304
305 /* ftag: Implication of setting TOP to 7 and indicating all st% registers
306 empty except st0 is to set
307 7th bit of 4th byte of FXSAVE area to 1 and all other bits of this byte to
308 0. This is in accordance
309 with the document Intel 64 and IA-32 Architectures Software Developer's
310 Manual, January 2015 */
311 uint32_t value_ftag_u32 = 0x00000080;
312
313 if (num_bytes <= 12) // handles float, double, long double, __float80
314 {
315 long double value_long_dbl = 0.0;
316 if (num_bytes == 4)
317 value_long_dbl = data.GetFloat(offset_ptr: &offset);
318 else if (num_bytes == 8)
319 value_long_dbl = data.GetDouble(offset_ptr: &offset);
320 else if (num_bytes == 12)
321 value_long_dbl = data.GetLongDouble(offset_ptr: &offset);
322 else {
323 error = Status::FromErrorString(
324 str: "Invalid number of bytes for this return type");
325 return error;
326 }
327 st0_value.SetLongDouble(value_long_dbl);
328 fstat_value.SetUInt32(uint: value_fstat_u32);
329 ftag_value.SetUInt32(uint: value_ftag_u32);
330 register_write_successful =
331 reg_ctx->WriteRegister(reg_info: st0_info, reg_value: st0_value) &&
332 reg_ctx->WriteRegister(reg_info: fstat_info, reg_value: fstat_value) &&
333 reg_ctx->WriteRegister(reg_info: ftag_info, reg_value: ftag_value);
334 } else if (num_bytes == 16) // handles __float128
335 {
336 error = Status::FromErrorString(
337 str: "Implementation is missing for this clang type.");
338 }
339 } else {
340 // Neither 'Integral' nor 'Floating Point'. If flow reaches here then
341 // check type_flags. This type_flags is not a valid type.
342 error = Status::FromErrorString(str: "Invalid clang type");
343 }
344 } else {
345 /* 'Complex Floating Point', 'Packed', 'Decimal Floating Point' and
346 'Aggregate' data types
347 are yet to be implemented */
348 error = Status::FromErrorString(
349 str: "Currently only Integral and Floating Point clang "
350 "types are supported.");
351 }
352 if (!register_write_successful)
353 error = Status::FromErrorString(str: "Register writing failed");
354 return error;
355}
356
357ValueObjectSP ABISysV_i386::GetReturnValueObjectSimple(
358 Thread &thread, CompilerType &return_compiler_type) const {
359 ValueObjectSP return_valobj_sp;
360 Value value;
361
362 if (!return_compiler_type)
363 return return_valobj_sp;
364
365 value.SetCompilerType(return_compiler_type);
366
367 RegisterContext *reg_ctx = thread.GetRegisterContext().get();
368 if (!reg_ctx)
369 return return_valobj_sp;
370
371 const uint32_t type_flags = return_compiler_type.GetTypeInfo();
372
373 unsigned eax_id =
374 reg_ctx->GetRegisterInfoByName(reg_name: "eax", start_idx: 0)->kinds[eRegisterKindLLDB];
375 unsigned edx_id =
376 reg_ctx->GetRegisterInfoByName(reg_name: "edx", start_idx: 0)->kinds[eRegisterKindLLDB];
377
378 // Following "IF ELSE" block categorizes various 'Fundamental Data Types'.
379 // The terminology 'Fundamental Data Types' used here is adopted from Table
380 // 2.1 of the reference document (specified on top of this file)
381
382 if (type_flags & eTypeIsPointer) // 'Pointer'
383 {
384 uint32_t ptr =
385 thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg: eax_id, fail_value: 0) &
386 0xffffffff;
387 value.SetValueType(Value::ValueType::Scalar);
388 value.GetScalar() = ptr;
389 return_valobj_sp = ValueObjectConstResult::Create(
390 exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(), value, name: ConstString(""));
391 } else if ((type_flags & eTypeIsScalar) ||
392 (type_flags & eTypeIsEnumeration)) //'Integral' + 'Floating Point'
393 {
394 value.SetValueType(Value::ValueType::Scalar);
395 std::optional<uint64_t> byte_size =
396 llvm::expectedToOptional(E: return_compiler_type.GetByteSize(exe_scope: &thread));
397 if (!byte_size)
398 return return_valobj_sp;
399 bool success = false;
400
401 if (type_flags & eTypeIsInteger) // 'Integral' except enum
402 {
403 const bool is_signed = ((type_flags & eTypeIsSigned) != 0);
404 uint64_t raw_value =
405 thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg: eax_id, fail_value: 0) &
406 0xffffffff;
407 raw_value |=
408 (thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg: edx_id, fail_value: 0) &
409 0xffffffff)
410 << 32;
411
412 switch (*byte_size) {
413 default:
414 break;
415
416 case 16:
417 // For clang::BuiltinType::UInt128 & Int128 ToDo: Need to decide how to
418 // handle it
419 break;
420
421 case 8:
422 if (is_signed)
423 value.GetScalar() = (int64_t)(raw_value);
424 else
425 value.GetScalar() = (uint64_t)(raw_value);
426 success = true;
427 break;
428
429 case 4:
430 if (is_signed)
431 value.GetScalar() = (int32_t)(raw_value & UINT32_MAX);
432 else
433 value.GetScalar() = (uint32_t)(raw_value & UINT32_MAX);
434 success = true;
435 break;
436
437 case 2:
438 if (is_signed)
439 value.GetScalar() = (int16_t)(raw_value & UINT16_MAX);
440 else
441 value.GetScalar() = (uint16_t)(raw_value & UINT16_MAX);
442 success = true;
443 break;
444
445 case 1:
446 if (is_signed)
447 value.GetScalar() = (int8_t)(raw_value & UINT8_MAX);
448 else
449 value.GetScalar() = (uint8_t)(raw_value & UINT8_MAX);
450 success = true;
451 break;
452 }
453
454 if (success)
455 return_valobj_sp = ValueObjectConstResult::Create(
456 exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(), value, name: ConstString(""));
457 } else if (type_flags & eTypeIsEnumeration) // handles enum
458 {
459 uint32_t enm =
460 thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg: eax_id, fail_value: 0) &
461 0xffffffff;
462 value.SetValueType(Value::ValueType::Scalar);
463 value.GetScalar() = enm;
464 return_valobj_sp = ValueObjectConstResult::Create(
465 exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(), value, name: ConstString(""));
466 } else if (type_flags & eTypeIsFloat) // 'Floating Point'
467 {
468 if (*byte_size <= 12) // handles float, double, long double, __float80
469 {
470 const RegisterInfo *st0_info = reg_ctx->GetRegisterInfoByName(reg_name: "st0", start_idx: 0);
471 RegisterValue st0_value;
472
473 if (reg_ctx->ReadRegister(reg_info: st0_info, reg_value&: st0_value)) {
474 DataExtractor data;
475 if (st0_value.GetData(data)) {
476 lldb::offset_t offset = 0;
477 long double value_long_double = data.GetLongDouble(offset_ptr: &offset);
478
479 // float is 4 bytes.
480 if (*byte_size == 4) {
481 float value_float = (float)value_long_double;
482 value.GetScalar() = value_float;
483 success = true;
484 } else if (*byte_size == 8) {
485 // double is 8 bytes
486 // On Android Platform: long double is also 8 bytes It will be
487 // handled here only.
488 double value_double = (double)value_long_double;
489 value.GetScalar() = value_double;
490 success = true;
491 } else if (*byte_size == 12) {
492 // long double and __float80 are 12 bytes on i386.
493 value.GetScalar() = value_long_double;
494 success = true;
495 }
496 }
497 }
498
499 if (success)
500 return_valobj_sp = ValueObjectConstResult::Create(
501 exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(), value, name: ConstString(""));
502 } else if (*byte_size == 16) // handles __float128
503 {
504 lldb::addr_t storage_addr = (uint32_t)(
505 thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg: eax_id, fail_value: 0) &
506 0xffffffff);
507 return_valobj_sp = ValueObjectMemory::Create(
508 exe_scope: &thread, name: "", address: Address(storage_addr, nullptr), ast_type: return_compiler_type);
509 }
510 } else // Neither 'Integral' nor 'Floating Point'
511 {
512 // If flow reaches here then check type_flags This type_flags is
513 // unhandled
514 }
515 } else if (type_flags & eTypeIsComplex) // 'Complex Floating Point'
516 {
517 // ToDo: Yet to be implemented
518 } else if (type_flags & eTypeIsVector) // 'Packed'
519 {
520 std::optional<uint64_t> byte_size =
521 llvm::expectedToOptional(E: return_compiler_type.GetByteSize(exe_scope: &thread));
522 if (byte_size && *byte_size > 0) {
523 const RegisterInfo *vec_reg = reg_ctx->GetRegisterInfoByName(reg_name: "xmm0", start_idx: 0);
524 if (vec_reg == nullptr)
525 vec_reg = reg_ctx->GetRegisterInfoByName(reg_name: "mm0", start_idx: 0);
526
527 if (vec_reg) {
528 if (*byte_size <= vec_reg->byte_size) {
529 ProcessSP process_sp(thread.GetProcess());
530 if (process_sp) {
531 std::unique_ptr<DataBufferHeap> heap_data_up(
532 new DataBufferHeap(*byte_size, 0));
533 const ByteOrder byte_order = process_sp->GetByteOrder();
534 RegisterValue reg_value;
535 if (reg_ctx->ReadRegister(reg_info: vec_reg, reg_value)) {
536 Status error;
537 if (reg_value.GetAsMemoryData(reg_info: *vec_reg, dst: heap_data_up->GetBytes(),
538 dst_len: heap_data_up->GetByteSize(),
539 dst_byte_order: byte_order, error)) {
540 DataExtractor data(DataBufferSP(heap_data_up.release()),
541 byte_order,
542 process_sp->GetTarget()
543 .GetArchitecture()
544 .GetAddressByteSize());
545 return_valobj_sp = ValueObjectConstResult::Create(
546 exe_scope: &thread, compiler_type: return_compiler_type, name: ConstString(""), data);
547 }
548 }
549 }
550 } else if (*byte_size <= vec_reg->byte_size * 2) {
551 const RegisterInfo *vec_reg2 =
552 reg_ctx->GetRegisterInfoByName(reg_name: "xmm1", start_idx: 0);
553 if (vec_reg2) {
554 ProcessSP process_sp(thread.GetProcess());
555 if (process_sp) {
556 std::unique_ptr<DataBufferHeap> heap_data_up(
557 new DataBufferHeap(*byte_size, 0));
558 const ByteOrder byte_order = process_sp->GetByteOrder();
559 RegisterValue reg_value;
560 RegisterValue reg_value2;
561 if (reg_ctx->ReadRegister(reg_info: vec_reg, reg_value) &&
562 reg_ctx->ReadRegister(reg_info: vec_reg2, reg_value&: reg_value2)) {
563
564 Status error;
565 if (reg_value.GetAsMemoryData(
566 reg_info: *vec_reg, dst: heap_data_up->GetBytes(), dst_len: vec_reg->byte_size,
567 dst_byte_order: byte_order, error) &&
568 reg_value2.GetAsMemoryData(
569 reg_info: *vec_reg2,
570 dst: heap_data_up->GetBytes() + vec_reg->byte_size,
571 dst_len: heap_data_up->GetByteSize() - vec_reg->byte_size,
572 dst_byte_order: byte_order, error)) {
573 DataExtractor data(DataBufferSP(heap_data_up.release()),
574 byte_order,
575 process_sp->GetTarget()
576 .GetArchitecture()
577 .GetAddressByteSize());
578 return_valobj_sp = ValueObjectConstResult::Create(
579 exe_scope: &thread, compiler_type: return_compiler_type, name: ConstString(""), data);
580 }
581 }
582 }
583 }
584 }
585 }
586 }
587 } else // 'Decimal Floating Point'
588 {
589 // ToDo: Yet to be implemented
590 }
591 return return_valobj_sp;
592}
593
594ValueObjectSP ABISysV_i386::GetReturnValueObjectImpl(
595 Thread &thread, CompilerType &return_compiler_type) const {
596 ValueObjectSP return_valobj_sp;
597
598 if (!return_compiler_type)
599 return return_valobj_sp;
600
601 ExecutionContext exe_ctx(thread.shared_from_this());
602 return_valobj_sp = GetReturnValueObjectSimple(thread, return_compiler_type);
603 if (return_valobj_sp)
604 return return_valobj_sp;
605
606 RegisterContextSP reg_ctx_sp = thread.GetRegisterContext();
607 if (!reg_ctx_sp)
608 return return_valobj_sp;
609
610 if (return_compiler_type.IsAggregateType()) {
611 unsigned eax_id =
612 reg_ctx_sp->GetRegisterInfoByName(reg_name: "eax", start_idx: 0)->kinds[eRegisterKindLLDB];
613 lldb::addr_t storage_addr = (uint32_t)(
614 thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg: eax_id, fail_value: 0) &
615 0xffffffff);
616 return_valobj_sp = ValueObjectMemory::Create(
617 exe_scope: &thread, name: "", address: Address(storage_addr, nullptr), ast_type: return_compiler_type);
618 }
619
620 return return_valobj_sp;
621}
622
623// This defines CFA as esp+4
624// The saved pc is at CFA-4 (i.e. esp+0)
625// The saved esp is CFA+0
626
627UnwindPlanSP ABISysV_i386::CreateFunctionEntryUnwindPlan() {
628 uint32_t sp_reg_num = dwarf_esp;
629 uint32_t pc_reg_num = dwarf_eip;
630
631 UnwindPlan::Row row;
632 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num: sp_reg_num, offset: 4);
633 row.SetRegisterLocationToAtCFAPlusOffset(reg_num: pc_reg_num, offset: -4, can_replace: false);
634 row.SetRegisterLocationToIsCFAPlusOffset(reg_num: sp_reg_num, offset: 0, can_replace: true);
635
636 auto plan_sp = std::make_shared<UnwindPlan>(args: eRegisterKindDWARF);
637 plan_sp->AppendRow(row: std::move(row));
638 plan_sp->SetSourceName("i386 at-func-entry default");
639 plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
640 return plan_sp;
641}
642
643// This defines CFA as ebp+8
644// The saved pc is at CFA-4 (i.e. ebp+4)
645// The saved ebp is at CFA-8 (i.e. ebp+0)
646// The saved esp is CFA+0
647
648UnwindPlanSP ABISysV_i386::CreateDefaultUnwindPlan() {
649 uint32_t fp_reg_num = dwarf_ebp;
650 uint32_t sp_reg_num = dwarf_esp;
651 uint32_t pc_reg_num = dwarf_eip;
652
653 UnwindPlan::Row row;
654 const int32_t ptr_size = 4;
655
656 row.GetCFAValue().SetIsRegisterPlusOffset(reg_num: fp_reg_num, offset: 2 * ptr_size);
657 row.SetUnspecifiedRegistersAreUndefined(true);
658
659 row.SetRegisterLocationToAtCFAPlusOffset(reg_num: fp_reg_num, offset: ptr_size * -2, can_replace: true);
660 row.SetRegisterLocationToAtCFAPlusOffset(reg_num: pc_reg_num, offset: ptr_size * -1, can_replace: true);
661 row.SetRegisterLocationToIsCFAPlusOffset(reg_num: sp_reg_num, offset: 0, can_replace: true);
662
663 auto plan_sp = std::make_shared<UnwindPlan>(args: eRegisterKindDWARF);
664 plan_sp->AppendRow(row: std::move(row));
665 plan_sp->SetSourceName("i386 default unwind plan");
666 plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
667 plan_sp->SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
668 plan_sp->SetUnwindPlanForSignalTrap(eLazyBoolNo);
669 return plan_sp;
670}
671
672// According to "Register Usage" in reference document (specified on top of
673// this source file) ebx, ebp, esi, edi and esp registers are preserved i.e.
674// non-volatile i.e. callee-saved on i386
675bool ABISysV_i386::RegisterIsCalleeSaved(const RegisterInfo *reg_info) {
676 if (!reg_info)
677 return false;
678
679 // Saved registers are ebx, ebp, esi, edi, esp, eip
680 const char *name = reg_info->name;
681 if (name[0] == 'e') {
682 switch (name[1]) {
683 case 'b':
684 if (name[2] == 'x' || name[2] == 'p')
685 return name[3] == '\0';
686 break;
687 case 'd':
688 if (name[2] == 'i')
689 return name[3] == '\0';
690 break;
691 case 'i':
692 if (name[2] == 'p')
693 return name[3] == '\0';
694 break;
695 case 's':
696 if (name[2] == 'i' || name[2] == 'p')
697 return name[3] == '\0';
698 break;
699 }
700 }
701
702 if (name[0] == 's' && name[1] == 'p' && name[2] == '\0') // sp
703 return true;
704 if (name[0] == 'f' && name[1] == 'p' && name[2] == '\0') // fp
705 return true;
706 if (name[0] == 'p' && name[1] == 'c' && name[2] == '\0') // pc
707 return true;
708
709 return false;
710}
711
712void ABISysV_i386::Initialize() {
713 PluginManager::RegisterPlugin(
714 name: GetPluginNameStatic(), description: "System V ABI for i386 targets", create_callback: CreateInstance);
715}
716
717void ABISysV_i386::Terminate() {
718 PluginManager::UnregisterPlugin(create_callback: CreateInstance);
719}
720

source code of lldb/source/Plugins/ABI/X86/ABISysV_i386.cpp