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/Core/ValueObjectConstResult.h"
17#include "lldb/Core/ValueObjectMemory.h"
18#include "lldb/Core/ValueObjectRegister.h"
19#include "lldb/Symbol/UnwindPlan.h"
20#include "lldb/Target/Process.h"
21#include "lldb/Target/RegisterContext.h"
22#include "lldb/Target/StackFrame.h"
23#include "lldb/Target/Target.h"
24#include "lldb/Target/Thread.h"
25#include "lldb/Utility/ConstString.h"
26#include "lldb/Utility/DataExtractor.h"
27#include "lldb/Utility/Log.h"
28#include "lldb/Utility/RegisterValue.h"
29#include "lldb/Utility/Status.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 = compiler_type.GetBitSize(exe_scope: &thread);
186 if (bit_size) {
187 bool is_signed;
188 if (compiler_type.IsIntegerOrEnumerationType(is_signed)) {
189 ReadIntegerArgument(scalar&: value->GetScalar(), bit_width: *bit_size, is_signed,
190 process: thread.GetProcess().get(), current_stack_argument);
191 } else if (compiler_type.IsPointerType()) {
192 ReadIntegerArgument(scalar&: value->GetScalar(), bit_width: *bit_size, is_signed: false,
193 process: thread.GetProcess().get(), current_stack_argument);
194 }
195 }
196 }
197 return true;
198}
199
200Status ABISysV_i386::SetReturnValueObject(lldb::StackFrameSP &frame_sp,
201 lldb::ValueObjectSP &new_value_sp) {
202 Status error;
203 if (!new_value_sp) {
204 error.SetErrorString("Empty value object for return value.");
205 return error;
206 }
207
208 CompilerType compiler_type = new_value_sp->GetCompilerType();
209 if (!compiler_type) {
210 error.SetErrorString("Null clang type for return value.");
211 return error;
212 }
213
214 const uint32_t type_flags = compiler_type.GetTypeInfo();
215 Thread *thread = frame_sp->GetThread().get();
216 RegisterContext *reg_ctx = thread->GetRegisterContext().get();
217 DataExtractor data;
218 Status data_error;
219 size_t num_bytes = new_value_sp->GetData(data, error&: data_error);
220 bool register_write_successful = true;
221
222 if (data_error.Fail()) {
223 error.SetErrorStringWithFormat(
224 "Couldn't convert return value to raw data: %s",
225 data_error.AsCString());
226 return error;
227 }
228
229 // Following "IF ELSE" block categorizes various 'Fundamental Data Types'.
230 // The terminology 'Fundamental Data Types' used here is adopted from Table
231 // 2.1 of the reference document (specified on top of this file)
232
233 if (type_flags & eTypeIsPointer) // 'Pointer'
234 {
235 if (num_bytes != sizeof(uint32_t)) {
236 error.SetErrorString("Pointer to be returned is not 4 bytes wide");
237 return error;
238 }
239 lldb::offset_t offset = 0;
240 const RegisterInfo *eax_info = reg_ctx->GetRegisterInfoByName(reg_name: "eax", start_idx: 0);
241 uint32_t raw_value = data.GetMaxU32(offset_ptr: &offset, byte_size: num_bytes);
242 register_write_successful =
243 reg_ctx->WriteRegisterFromUnsigned(reg_info: eax_info, uval: raw_value);
244 } else if ((type_flags & eTypeIsScalar) ||
245 (type_flags & eTypeIsEnumeration)) //'Integral' + 'Floating Point'
246 {
247 lldb::offset_t offset = 0;
248 const RegisterInfo *eax_info = reg_ctx->GetRegisterInfoByName(reg_name: "eax", start_idx: 0);
249
250 if (type_flags & eTypeIsInteger) // 'Integral' except enum
251 {
252 switch (num_bytes) {
253 default:
254 break;
255 case 16:
256 // For clang::BuiltinType::UInt128 & Int128 ToDo: Need to decide how to
257 // handle it
258 break;
259 case 8: {
260 uint32_t raw_value_low = data.GetMaxU32(offset_ptr: &offset, byte_size: 4);
261 const RegisterInfo *edx_info = reg_ctx->GetRegisterInfoByName(reg_name: "edx", start_idx: 0);
262 uint32_t raw_value_high = data.GetMaxU32(offset_ptr: &offset, byte_size: num_bytes - offset);
263 register_write_successful =
264 (reg_ctx->WriteRegisterFromUnsigned(reg_info: eax_info, uval: raw_value_low) &&
265 reg_ctx->WriteRegisterFromUnsigned(reg_info: edx_info, uval: raw_value_high));
266 break;
267 }
268 case 4:
269 case 2:
270 case 1: {
271 uint32_t raw_value = data.GetMaxU32(offset_ptr: &offset, byte_size: num_bytes);
272 register_write_successful =
273 reg_ctx->WriteRegisterFromUnsigned(reg_info: eax_info, uval: raw_value);
274 break;
275 }
276 }
277 } else if (type_flags & eTypeIsEnumeration) // handles enum
278 {
279 uint32_t raw_value = data.GetMaxU32(offset_ptr: &offset, byte_size: num_bytes);
280 register_write_successful =
281 reg_ctx->WriteRegisterFromUnsigned(reg_info: eax_info, uval: raw_value);
282 } else if (type_flags & eTypeIsFloat) // 'Floating Point'
283 {
284 RegisterValue st0_value, fstat_value, ftag_value;
285 const RegisterInfo *st0_info = reg_ctx->GetRegisterInfoByName(reg_name: "st0", start_idx: 0);
286 const RegisterInfo *fstat_info =
287 reg_ctx->GetRegisterInfoByName(reg_name: "fstat", start_idx: 0);
288 const RegisterInfo *ftag_info = reg_ctx->GetRegisterInfoByName(reg_name: "ftag", start_idx: 0);
289
290 /* According to Page 3-12 of document
291 System V Application Binary Interface, Intel386 Architecture Processor
292 Supplement, Fourth Edition
293 To return Floating Point values, all st% registers except st0 should be
294 empty after exiting from
295 a function. This requires setting fstat and ftag registers to specific
296 values.
297 fstat: The TOP field of fstat should be set to a value [0,7]. ABI doesn't
298 specify the specific
299 value of TOP in case of function return. Hence, we set the TOP field to 7
300 by our choice. */
301 uint32_t value_fstat_u32 = 0x00003800;
302
303 /* ftag: Implication of setting TOP to 7 and indicating all st% registers
304 empty except st0 is to set
305 7th bit of 4th byte of FXSAVE area to 1 and all other bits of this byte to
306 0. This is in accordance
307 with the document Intel 64 and IA-32 Architectures Software Developer's
308 Manual, January 2015 */
309 uint32_t value_ftag_u32 = 0x00000080;
310
311 if (num_bytes <= 12) // handles float, double, long double, __float80
312 {
313 long double value_long_dbl = 0.0;
314 if (num_bytes == 4)
315 value_long_dbl = data.GetFloat(offset_ptr: &offset);
316 else if (num_bytes == 8)
317 value_long_dbl = data.GetDouble(offset_ptr: &offset);
318 else if (num_bytes == 12)
319 value_long_dbl = data.GetLongDouble(offset_ptr: &offset);
320 else {
321 error.SetErrorString("Invalid number of bytes for this return type");
322 return error;
323 }
324 st0_value.SetLongDouble(value_long_dbl);
325 fstat_value.SetUInt32(uint: value_fstat_u32);
326 ftag_value.SetUInt32(uint: value_ftag_u32);
327 register_write_successful =
328 reg_ctx->WriteRegister(reg_info: st0_info, reg_value: st0_value) &&
329 reg_ctx->WriteRegister(reg_info: fstat_info, reg_value: fstat_value) &&
330 reg_ctx->WriteRegister(reg_info: ftag_info, reg_value: ftag_value);
331 } else if (num_bytes == 16) // handles __float128
332 {
333 error.SetErrorString("Implementation is missing for this clang type.");
334 }
335 } else {
336 // Neither 'Integral' nor 'Floating Point'. If flow reaches here then
337 // check type_flags. This type_flags is not a valid type.
338 error.SetErrorString("Invalid clang type");
339 }
340 } else {
341 /* 'Complex Floating Point', 'Packed', 'Decimal Floating Point' and
342 'Aggregate' data types
343 are yet to be implemented */
344 error.SetErrorString("Currently only Integral and Floating Point clang "
345 "types are supported.");
346 }
347 if (!register_write_successful)
348 error.SetErrorString("Register writing failed");
349 return error;
350}
351
352ValueObjectSP ABISysV_i386::GetReturnValueObjectSimple(
353 Thread &thread, CompilerType &return_compiler_type) const {
354 ValueObjectSP return_valobj_sp;
355 Value value;
356
357 if (!return_compiler_type)
358 return return_valobj_sp;
359
360 value.SetCompilerType(return_compiler_type);
361
362 RegisterContext *reg_ctx = thread.GetRegisterContext().get();
363 if (!reg_ctx)
364 return return_valobj_sp;
365
366 const uint32_t type_flags = return_compiler_type.GetTypeInfo();
367
368 unsigned eax_id =
369 reg_ctx->GetRegisterInfoByName(reg_name: "eax", start_idx: 0)->kinds[eRegisterKindLLDB];
370 unsigned edx_id =
371 reg_ctx->GetRegisterInfoByName(reg_name: "edx", start_idx: 0)->kinds[eRegisterKindLLDB];
372
373 // Following "IF ELSE" block categorizes various 'Fundamental Data Types'.
374 // The terminology 'Fundamental Data Types' used here is adopted from Table
375 // 2.1 of the reference document (specified on top of this file)
376
377 if (type_flags & eTypeIsPointer) // 'Pointer'
378 {
379 uint32_t ptr =
380 thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg: eax_id, fail_value: 0) &
381 0xffffffff;
382 value.SetValueType(Value::ValueType::Scalar);
383 value.GetScalar() = ptr;
384 return_valobj_sp = ValueObjectConstResult::Create(
385 exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(), value, name: ConstString(""));
386 } else if ((type_flags & eTypeIsScalar) ||
387 (type_flags & eTypeIsEnumeration)) //'Integral' + 'Floating Point'
388 {
389 value.SetValueType(Value::ValueType::Scalar);
390 std::optional<uint64_t> byte_size =
391 return_compiler_type.GetByteSize(exe_scope: &thread);
392 if (!byte_size)
393 return return_valobj_sp;
394 bool success = false;
395
396 if (type_flags & eTypeIsInteger) // 'Integral' except enum
397 {
398 const bool is_signed = ((type_flags & eTypeIsSigned) != 0);
399 uint64_t raw_value =
400 thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg: eax_id, fail_value: 0) &
401 0xffffffff;
402 raw_value |=
403 (thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg: edx_id, fail_value: 0) &
404 0xffffffff)
405 << 32;
406
407 switch (*byte_size) {
408 default:
409 break;
410
411 case 16:
412 // For clang::BuiltinType::UInt128 & Int128 ToDo: Need to decide how to
413 // handle it
414 break;
415
416 case 8:
417 if (is_signed)
418 value.GetScalar() = (int64_t)(raw_value);
419 else
420 value.GetScalar() = (uint64_t)(raw_value);
421 success = true;
422 break;
423
424 case 4:
425 if (is_signed)
426 value.GetScalar() = (int32_t)(raw_value & UINT32_MAX);
427 else
428 value.GetScalar() = (uint32_t)(raw_value & UINT32_MAX);
429 success = true;
430 break;
431
432 case 2:
433 if (is_signed)
434 value.GetScalar() = (int16_t)(raw_value & UINT16_MAX);
435 else
436 value.GetScalar() = (uint16_t)(raw_value & UINT16_MAX);
437 success = true;
438 break;
439
440 case 1:
441 if (is_signed)
442 value.GetScalar() = (int8_t)(raw_value & UINT8_MAX);
443 else
444 value.GetScalar() = (uint8_t)(raw_value & UINT8_MAX);
445 success = true;
446 break;
447 }
448
449 if (success)
450 return_valobj_sp = ValueObjectConstResult::Create(
451 exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(), value, name: ConstString(""));
452 } else if (type_flags & eTypeIsEnumeration) // handles enum
453 {
454 uint32_t enm =
455 thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg: eax_id, fail_value: 0) &
456 0xffffffff;
457 value.SetValueType(Value::ValueType::Scalar);
458 value.GetScalar() = enm;
459 return_valobj_sp = ValueObjectConstResult::Create(
460 exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(), value, name: ConstString(""));
461 } else if (type_flags & eTypeIsFloat) // 'Floating Point'
462 {
463 if (*byte_size <= 12) // handles float, double, long double, __float80
464 {
465 const RegisterInfo *st0_info = reg_ctx->GetRegisterInfoByName(reg_name: "st0", start_idx: 0);
466 RegisterValue st0_value;
467
468 if (reg_ctx->ReadRegister(reg_info: st0_info, reg_value&: st0_value)) {
469 DataExtractor data;
470 if (st0_value.GetData(data)) {
471 lldb::offset_t offset = 0;
472 long double value_long_double = data.GetLongDouble(offset_ptr: &offset);
473
474 // float is 4 bytes.
475 if (*byte_size == 4) {
476 float value_float = (float)value_long_double;
477 value.GetScalar() = value_float;
478 success = true;
479 } else if (*byte_size == 8) {
480 // double is 8 bytes
481 // On Android Platform: long double is also 8 bytes It will be
482 // handled here only.
483 double value_double = (double)value_long_double;
484 value.GetScalar() = value_double;
485 success = true;
486 } else if (*byte_size == 12) {
487 // long double and __float80 are 12 bytes on i386.
488 value.GetScalar() = value_long_double;
489 success = true;
490 }
491 }
492 }
493
494 if (success)
495 return_valobj_sp = ValueObjectConstResult::Create(
496 exe_scope: thread.GetStackFrameAtIndex(idx: 0).get(), value, name: ConstString(""));
497 } else if (*byte_size == 16) // handles __float128
498 {
499 lldb::addr_t storage_addr = (uint32_t)(
500 thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg: eax_id, fail_value: 0) &
501 0xffffffff);
502 return_valobj_sp = ValueObjectMemory::Create(
503 exe_scope: &thread, name: "", address: Address(storage_addr, nullptr), ast_type: return_compiler_type);
504 }
505 } else // Neither 'Integral' nor 'Floating Point'
506 {
507 // If flow reaches here then check type_flags This type_flags is
508 // unhandled
509 }
510 } else if (type_flags & eTypeIsComplex) // 'Complex Floating Point'
511 {
512 // ToDo: Yet to be implemented
513 } else if (type_flags & eTypeIsVector) // 'Packed'
514 {
515 std::optional<uint64_t> byte_size =
516 return_compiler_type.GetByteSize(exe_scope: &thread);
517 if (byte_size && *byte_size > 0) {
518 const RegisterInfo *vec_reg = reg_ctx->GetRegisterInfoByName(reg_name: "xmm0", start_idx: 0);
519 if (vec_reg == nullptr)
520 vec_reg = reg_ctx->GetRegisterInfoByName(reg_name: "mm0", start_idx: 0);
521
522 if (vec_reg) {
523 if (*byte_size <= vec_reg->byte_size) {
524 ProcessSP process_sp(thread.GetProcess());
525 if (process_sp) {
526 std::unique_ptr<DataBufferHeap> heap_data_up(
527 new DataBufferHeap(*byte_size, 0));
528 const ByteOrder byte_order = process_sp->GetByteOrder();
529 RegisterValue reg_value;
530 if (reg_ctx->ReadRegister(reg_info: vec_reg, reg_value)) {
531 Status error;
532 if (reg_value.GetAsMemoryData(reg_info: *vec_reg, dst: heap_data_up->GetBytes(),
533 dst_len: heap_data_up->GetByteSize(),
534 dst_byte_order: byte_order, error)) {
535 DataExtractor data(DataBufferSP(heap_data_up.release()),
536 byte_order,
537 process_sp->GetTarget()
538 .GetArchitecture()
539 .GetAddressByteSize());
540 return_valobj_sp = ValueObjectConstResult::Create(
541 exe_scope: &thread, compiler_type: return_compiler_type, name: ConstString(""), data);
542 }
543 }
544 }
545 } else if (*byte_size <= vec_reg->byte_size * 2) {
546 const RegisterInfo *vec_reg2 =
547 reg_ctx->GetRegisterInfoByName(reg_name: "xmm1", start_idx: 0);
548 if (vec_reg2) {
549 ProcessSP process_sp(thread.GetProcess());
550 if (process_sp) {
551 std::unique_ptr<DataBufferHeap> heap_data_up(
552 new DataBufferHeap(*byte_size, 0));
553 const ByteOrder byte_order = process_sp->GetByteOrder();
554 RegisterValue reg_value;
555 RegisterValue reg_value2;
556 if (reg_ctx->ReadRegister(reg_info: vec_reg, reg_value) &&
557 reg_ctx->ReadRegister(reg_info: vec_reg2, reg_value&: reg_value2)) {
558
559 Status error;
560 if (reg_value.GetAsMemoryData(
561 reg_info: *vec_reg, dst: heap_data_up->GetBytes(), dst_len: vec_reg->byte_size,
562 dst_byte_order: byte_order, error) &&
563 reg_value2.GetAsMemoryData(
564 reg_info: *vec_reg2,
565 dst: heap_data_up->GetBytes() + vec_reg->byte_size,
566 dst_len: heap_data_up->GetByteSize() - vec_reg->byte_size,
567 dst_byte_order: byte_order, error)) {
568 DataExtractor data(DataBufferSP(heap_data_up.release()),
569 byte_order,
570 process_sp->GetTarget()
571 .GetArchitecture()
572 .GetAddressByteSize());
573 return_valobj_sp = ValueObjectConstResult::Create(
574 exe_scope: &thread, compiler_type: return_compiler_type, name: ConstString(""), data);
575 }
576 }
577 }
578 }
579 }
580 }
581 }
582 } else // 'Decimal Floating Point'
583 {
584 // ToDo: Yet to be implemented
585 }
586 return return_valobj_sp;
587}
588
589ValueObjectSP ABISysV_i386::GetReturnValueObjectImpl(
590 Thread &thread, CompilerType &return_compiler_type) const {
591 ValueObjectSP return_valobj_sp;
592
593 if (!return_compiler_type)
594 return return_valobj_sp;
595
596 ExecutionContext exe_ctx(thread.shared_from_this());
597 return_valobj_sp = GetReturnValueObjectSimple(thread, return_compiler_type);
598 if (return_valobj_sp)
599 return return_valobj_sp;
600
601 RegisterContextSP reg_ctx_sp = thread.GetRegisterContext();
602 if (!reg_ctx_sp)
603 return return_valobj_sp;
604
605 if (return_compiler_type.IsAggregateType()) {
606 unsigned eax_id =
607 reg_ctx_sp->GetRegisterInfoByName(reg_name: "eax", start_idx: 0)->kinds[eRegisterKindLLDB];
608 lldb::addr_t storage_addr = (uint32_t)(
609 thread.GetRegisterContext()->ReadRegisterAsUnsigned(reg: eax_id, fail_value: 0) &
610 0xffffffff);
611 return_valobj_sp = ValueObjectMemory::Create(
612 exe_scope: &thread, name: "", address: Address(storage_addr, nullptr), ast_type: return_compiler_type);
613 }
614
615 return return_valobj_sp;
616}
617
618// This defines CFA as esp+4
619// The saved pc is at CFA-4 (i.e. esp+0)
620// The saved esp is CFA+0
621
622bool ABISysV_i386::CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) {
623 unwind_plan.Clear();
624 unwind_plan.SetRegisterKind(eRegisterKindDWARF);
625
626 uint32_t sp_reg_num = dwarf_esp;
627 uint32_t pc_reg_num = dwarf_eip;
628
629 UnwindPlan::RowSP row(new UnwindPlan::Row);
630 row->GetCFAValue().SetIsRegisterPlusOffset(reg_num: sp_reg_num, offset: 4);
631 row->SetRegisterLocationToAtCFAPlusOffset(reg_num: pc_reg_num, offset: -4, can_replace: false);
632 row->SetRegisterLocationToIsCFAPlusOffset(reg_num: sp_reg_num, offset: 0, can_replace: true);
633 unwind_plan.AppendRow(row_sp: row);
634 unwind_plan.SetSourceName("i386 at-func-entry default");
635 unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);
636 return true;
637}
638
639// This defines CFA as ebp+8
640// The saved pc is at CFA-4 (i.e. ebp+4)
641// The saved ebp is at CFA-8 (i.e. ebp+0)
642// The saved esp is CFA+0
643
644bool ABISysV_i386::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
645 unwind_plan.Clear();
646 unwind_plan.SetRegisterKind(eRegisterKindDWARF);
647
648 uint32_t fp_reg_num = dwarf_ebp;
649 uint32_t sp_reg_num = dwarf_esp;
650 uint32_t pc_reg_num = dwarf_eip;
651
652 UnwindPlan::RowSP row(new UnwindPlan::Row);
653 const int32_t ptr_size = 4;
654
655 row->GetCFAValue().SetIsRegisterPlusOffset(reg_num: fp_reg_num, offset: 2 * ptr_size);
656 row->SetOffset(0);
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 unwind_plan.AppendRow(row_sp: row);
664 unwind_plan.SetSourceName("i386 default unwind plan");
665 unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);
666 unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
667 unwind_plan.SetUnwindPlanForSignalTrap(eLazyBoolNo);
668 return true;
669}
670
671// According to "Register Usage" in reference document (specified on top of
672// this source file) ebx, ebp, esi, edi and esp registers are preserved i.e.
673// non-volatile i.e. callee-saved on i386
674bool ABISysV_i386::RegisterIsCalleeSaved(const RegisterInfo *reg_info) {
675 if (!reg_info)
676 return false;
677
678 // Saved registers are ebx, ebp, esi, edi, esp, eip
679 const char *name = reg_info->name;
680 if (name[0] == 'e') {
681 switch (name[1]) {
682 case 'b':
683 if (name[2] == 'x' || name[2] == 'p')
684 return name[3] == '\0';
685 break;
686 case 'd':
687 if (name[2] == 'i')
688 return name[3] == '\0';
689 break;
690 case 'i':
691 if (name[2] == 'p')
692 return name[3] == '\0';
693 break;
694 case 's':
695 if (name[2] == 'i' || name[2] == 'p')
696 return name[3] == '\0';
697 break;
698 }
699 }
700
701 if (name[0] == 's' && name[1] == 'p' && name[2] == '\0') // sp
702 return true;
703 if (name[0] == 'f' && name[1] == 'p' && name[2] == '\0') // fp
704 return true;
705 if (name[0] == 'p' && name[1] == 'c' && name[2] == '\0') // pc
706 return true;
707
708 return false;
709}
710
711void ABISysV_i386::Initialize() {
712 PluginManager::RegisterPlugin(
713 name: GetPluginNameStatic(), description: "System V ABI for i386 targets", create_callback: CreateInstance);
714}
715
716void ABISysV_i386::Terminate() {
717 PluginManager::UnregisterPlugin(create_callback: CreateInstance);
718}
719

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