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bolt/deps/llvm-18.1.8/lldb/source/Plugins/ABI/X86/ABIMacOSX_i386.cpp
Sam Vervaeck 174b6f4d4e
Embed LLVM 18.1.8
2025-02-14 19:21:04 +01:00

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//===-- ABIMacOSX_i386.cpp ------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "ABIMacOSX_i386.h"
#include <optional>
#include <vector>
#include "llvm/ADT/STLExtras.h"
#include "llvm/TargetParser/Triple.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/ValueObjectConstResult.h"
#include "lldb/Symbol/UnwindPlan.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Utility/ConstString.h"
#include "lldb/Utility/RegisterValue.h"
#include "lldb/Utility/Scalar.h"
#include "lldb/Utility/Status.h"
using namespace lldb;
using namespace lldb_private;
LLDB_PLUGIN_DEFINE(ABIMacOSX_i386)
enum {
dwarf_eax = 0,
dwarf_ecx,
dwarf_edx,
dwarf_ebx,
dwarf_esp,
dwarf_ebp,
dwarf_esi,
dwarf_edi,
dwarf_eip,
};
size_t ABIMacOSX_i386::GetRedZoneSize() const { return 0; }
// Static Functions
ABISP
ABIMacOSX_i386::CreateInstance(lldb::ProcessSP process_sp, const ArchSpec &arch) {
if ((arch.GetTriple().getArch() == llvm::Triple::x86) &&
(arch.GetTriple().isMacOSX() || arch.GetTriple().isiOS() ||
arch.GetTriple().isWatchOS())) {
return ABISP(
new ABIMacOSX_i386(std::move(process_sp), MakeMCRegisterInfo(arch)));
}
return ABISP();
}
bool ABIMacOSX_i386::PrepareTrivialCall(Thread &thread, addr_t sp,
addr_t func_addr, addr_t return_addr,
llvm::ArrayRef<addr_t> args) const {
RegisterContext *reg_ctx = thread.GetRegisterContext().get();
if (!reg_ctx)
return false;
uint32_t pc_reg_num = reg_ctx->ConvertRegisterKindToRegisterNumber(
eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
uint32_t sp_reg_num = reg_ctx->ConvertRegisterKindToRegisterNumber(
eRegisterKindGeneric, LLDB_REGNUM_GENERIC_SP);
// When writing a register value down to memory, the register info used to
// write memory just needs to have the correct size of a 32 bit register, the
// actual register it pertains to is not important, just the size needs to be
// correct. Here we use "eax"...
const RegisterInfo *reg_info_32 = reg_ctx->GetRegisterInfoByName("eax");
if (!reg_info_32)
return false; // TODO this should actually never happen
// Make room for the argument(s) on the stack
Status error;
RegisterValue reg_value;
// Write any arguments onto the stack
sp -= 4 * args.size();
// Align the SP
sp &= ~(16ull - 1ull); // 16-byte alignment
addr_t arg_pos = sp;
for (addr_t arg : args) {
reg_value.SetUInt32(arg);
error = reg_ctx->WriteRegisterValueToMemory(
reg_info_32, arg_pos, reg_info_32->byte_size, reg_value);
if (error.Fail())
return false;
arg_pos += 4;
}
// The return address is pushed onto the stack (yes after we just set the
// alignment above!).
sp -= 4;
reg_value.SetUInt32(return_addr);
error = reg_ctx->WriteRegisterValueToMemory(
reg_info_32, sp, reg_info_32->byte_size, reg_value);
if (error.Fail())
return false;
// %esp is set to the actual stack value.
if (!reg_ctx->WriteRegisterFromUnsigned(sp_reg_num, sp))
return false;
// %eip is set to the address of the called function.
if (!reg_ctx->WriteRegisterFromUnsigned(pc_reg_num, func_addr))
return false;
return true;
}
static bool ReadIntegerArgument(Scalar &scalar, unsigned int bit_width,
bool is_signed, Process *process,
addr_t &current_stack_argument) {
uint32_t byte_size = (bit_width + (8 - 1)) / 8;
Status error;
if (process->ReadScalarIntegerFromMemory(current_stack_argument, byte_size,
is_signed, scalar, error)) {
current_stack_argument += byte_size;
return true;
}
return false;
}
bool ABIMacOSX_i386::GetArgumentValues(Thread &thread,
ValueList &values) const {
unsigned int num_values = values.GetSize();
unsigned int value_index;
// Get the pointer to the first stack argument so we have a place to start
// when reading data
RegisterContext *reg_ctx = thread.GetRegisterContext().get();
if (!reg_ctx)
return false;
addr_t sp = reg_ctx->GetSP(0);
if (!sp)
return false;
addr_t current_stack_argument = sp + 4; // jump over return address
for (value_index = 0; value_index < num_values; ++value_index) {
Value *value = values.GetValueAtIndex(value_index);
if (!value)
return false;
// We currently only support extracting values with Clang QualTypes. Do we
// care about others?
CompilerType compiler_type(value->GetCompilerType());
std::optional<uint64_t> bit_size = compiler_type.GetBitSize(&thread);
if (bit_size) {
bool is_signed;
if (compiler_type.IsIntegerOrEnumerationType(is_signed))
ReadIntegerArgument(value->GetScalar(), *bit_size, is_signed,
thread.GetProcess().get(), current_stack_argument);
else if (compiler_type.IsPointerType())
ReadIntegerArgument(value->GetScalar(), *bit_size, false,
thread.GetProcess().get(), current_stack_argument);
}
}
return true;
}
Status ABIMacOSX_i386::SetReturnValueObject(lldb::StackFrameSP &frame_sp,
lldb::ValueObjectSP &new_value_sp) {
Status error;
if (!new_value_sp) {
error.SetErrorString("Empty value object for return value.");
return error;
}
CompilerType compiler_type = new_value_sp->GetCompilerType();
if (!compiler_type) {
error.SetErrorString("Null clang type for return value.");
return error;
}
Thread *thread = frame_sp->GetThread().get();
bool is_signed;
uint32_t count;
bool is_complex;
RegisterContext *reg_ctx = thread->GetRegisterContext().get();
bool set_it_simple = false;
if (compiler_type.IsIntegerOrEnumerationType(is_signed) ||
compiler_type.IsPointerType()) {
DataExtractor data;
Status data_error;
size_t num_bytes = new_value_sp->GetData(data, data_error);
if (data_error.Fail()) {
error.SetErrorStringWithFormat(
"Couldn't convert return value to raw data: %s",
data_error.AsCString());
return error;
}
lldb::offset_t offset = 0;
if (num_bytes <= 8) {
const RegisterInfo *eax_info = reg_ctx->GetRegisterInfoByName("eax", 0);
if (num_bytes <= 4) {
uint32_t raw_value = data.GetMaxU32(&offset, num_bytes);
if (reg_ctx->WriteRegisterFromUnsigned(eax_info, raw_value))
set_it_simple = true;
} else {
uint32_t raw_value = data.GetMaxU32(&offset, 4);
if (reg_ctx->WriteRegisterFromUnsigned(eax_info, raw_value)) {
const RegisterInfo *edx_info =
reg_ctx->GetRegisterInfoByName("edx", 0);
uint32_t raw_value = data.GetMaxU32(&offset, num_bytes - offset);
if (reg_ctx->WriteRegisterFromUnsigned(edx_info, raw_value))
set_it_simple = true;
}
}
} else {
error.SetErrorString("We don't support returning longer than 64 bit "
"integer values at present.");
}
} else if (compiler_type.IsFloatingPointType(count, is_complex)) {
if (is_complex)
error.SetErrorString(
"We don't support returning complex values at present");
else
error.SetErrorString(
"We don't support returning float values at present");
}
if (!set_it_simple)
error.SetErrorString(
"We only support setting simple integer return types at present.");
return error;
}
ValueObjectSP
ABIMacOSX_i386::GetReturnValueObjectImpl(Thread &thread,
CompilerType &compiler_type) const {
Value value;
ValueObjectSP return_valobj_sp;
if (!compiler_type)
return return_valobj_sp;
// value.SetContext (Value::eContextTypeClangType,
// compiler_type.GetOpaqueQualType());
value.SetCompilerType(compiler_type);
RegisterContext *reg_ctx = thread.GetRegisterContext().get();
if (!reg_ctx)
return return_valobj_sp;
bool is_signed;
if (compiler_type.IsIntegerOrEnumerationType(is_signed)) {
std::optional<uint64_t> bit_width = compiler_type.GetBitSize(&thread);
if (!bit_width)
return return_valobj_sp;
unsigned eax_id =
reg_ctx->GetRegisterInfoByName("eax", 0)->kinds[eRegisterKindLLDB];
unsigned edx_id =
reg_ctx->GetRegisterInfoByName("edx", 0)->kinds[eRegisterKindLLDB];
switch (*bit_width) {
default:
case 128:
// Scalar can't hold 128-bit literals, so we don't handle this
return return_valobj_sp;
case 64:
uint64_t raw_value;
raw_value =
thread.GetRegisterContext()->ReadRegisterAsUnsigned(eax_id, 0) &
0xffffffff;
raw_value |=
(thread.GetRegisterContext()->ReadRegisterAsUnsigned(edx_id, 0) &
0xffffffff)
<< 32;
if (is_signed)
value.GetScalar() = (int64_t)raw_value;
else
value.GetScalar() = (uint64_t)raw_value;
break;
case 32:
if (is_signed)
value.GetScalar() = (int32_t)(
thread.GetRegisterContext()->ReadRegisterAsUnsigned(eax_id, 0) &
0xffffffff);
else
value.GetScalar() = (uint32_t)(
thread.GetRegisterContext()->ReadRegisterAsUnsigned(eax_id, 0) &
0xffffffff);
break;
case 16:
if (is_signed)
value.GetScalar() = (int16_t)(
thread.GetRegisterContext()->ReadRegisterAsUnsigned(eax_id, 0) &
0xffff);
else
value.GetScalar() = (uint16_t)(
thread.GetRegisterContext()->ReadRegisterAsUnsigned(eax_id, 0) &
0xffff);
break;
case 8:
if (is_signed)
value.GetScalar() = (int8_t)(
thread.GetRegisterContext()->ReadRegisterAsUnsigned(eax_id, 0) &
0xff);
else
value.GetScalar() = (uint8_t)(
thread.GetRegisterContext()->ReadRegisterAsUnsigned(eax_id, 0) &
0xff);
break;
}
} else if (compiler_type.IsPointerType()) {
unsigned eax_id =
reg_ctx->GetRegisterInfoByName("eax", 0)->kinds[eRegisterKindLLDB];
uint32_t ptr =
thread.GetRegisterContext()->ReadRegisterAsUnsigned(eax_id, 0) &
0xffffffff;
value.GetScalar() = ptr;
} else {
// not handled yet
return return_valobj_sp;
}
// If we get here, we have a valid Value, so make our ValueObject out of it:
return_valobj_sp = ValueObjectConstResult::Create(
thread.GetStackFrameAtIndex(0).get(), value, ConstString(""));
return return_valobj_sp;
}
// This defines the CFA as esp+4
// the saved pc is at CFA-4 (i.e. esp+0)
// The saved esp is CFA+0
bool ABIMacOSX_i386::CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) {
unwind_plan.Clear();
unwind_plan.SetRegisterKind(eRegisterKindDWARF);
uint32_t sp_reg_num = dwarf_esp;
uint32_t pc_reg_num = dwarf_eip;
UnwindPlan::RowSP row(new UnwindPlan::Row);
row->GetCFAValue().SetIsRegisterPlusOffset(sp_reg_num, 4);
row->SetRegisterLocationToAtCFAPlusOffset(pc_reg_num, -4, false);
row->SetRegisterLocationToIsCFAPlusOffset(sp_reg_num, 0, true);
unwind_plan.AppendRow(row);
unwind_plan.SetSourceName("i386 at-func-entry default");
unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);
return true;
}
// This defines the CFA as ebp+8
// The saved pc is at CFA-4 (i.e. ebp+4)
// The saved ebp is at CFA-8 (i.e. ebp+0)
// The saved esp is CFA+0
bool ABIMacOSX_i386::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
unwind_plan.Clear();
unwind_plan.SetRegisterKind(eRegisterKindDWARF);
uint32_t fp_reg_num = dwarf_ebp;
uint32_t sp_reg_num = dwarf_esp;
uint32_t pc_reg_num = dwarf_eip;
UnwindPlan::RowSP row(new UnwindPlan::Row);
const int32_t ptr_size = 4;
row->GetCFAValue().SetIsRegisterPlusOffset(fp_reg_num, 2 * ptr_size);
row->SetOffset(0);
row->SetUnspecifiedRegistersAreUndefined(true);
row->SetRegisterLocationToAtCFAPlusOffset(fp_reg_num, ptr_size * -2, true);
row->SetRegisterLocationToAtCFAPlusOffset(pc_reg_num, ptr_size * -1, true);
row->SetRegisterLocationToIsCFAPlusOffset(sp_reg_num, 0, true);
unwind_plan.AppendRow(row);
unwind_plan.SetSourceName("i386 default unwind plan");
unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);
unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
unwind_plan.SetUnwindPlanForSignalTrap(eLazyBoolNo);
return true;
}
bool ABIMacOSX_i386::RegisterIsVolatile(const RegisterInfo *reg_info) {
return !RegisterIsCalleeSaved(reg_info);
}
// v.
// http://developer.apple.com/library/mac/#documentation/developertools/Conceptual/LowLevelABI/130
// -IA-
// 32_Function_Calling_Conventions/IA32.html#//apple_ref/doc/uid/TP40002492-SW4
//
// This document ("OS X ABI Function Call Guide", chapter "IA-32 Function
// Calling Conventions") says that the following registers on i386 are
// preserved aka non-volatile aka callee-saved:
//
// ebx, ebp, esi, edi, esp
bool ABIMacOSX_i386::RegisterIsCalleeSaved(const RegisterInfo *reg_info) {
if (reg_info) {
// Saved registers are ebx, ebp, esi, edi, esp, eip
const char *name = reg_info->name;
if (name[0] == 'e') {
switch (name[1]) {
case 'b':
if (name[2] == 'x' || name[2] == 'p')
return name[3] == '\0';
break;
case 'd':
if (name[2] == 'i')
return name[3] == '\0';
break;
case 'i':
if (name[2] == 'p')
return name[3] == '\0';
break;
case 's':
if (name[2] == 'i' || name[2] == 'p')
return name[3] == '\0';
break;
}
}
if (name[0] == 's' && name[1] == 'p' && name[2] == '\0') // sp
return true;
if (name[0] == 'f' && name[1] == 'p' && name[2] == '\0') // fp
return true;
if (name[0] == 'p' && name[1] == 'c' && name[2] == '\0') // pc
return true;
}
return false;
}
void ABIMacOSX_i386::Initialize() {
PluginManager::RegisterPlugin(
GetPluginNameStatic(), "Mac OS X ABI for i386 targets", CreateInstance);
}
void ABIMacOSX_i386::Terminate() {
PluginManager::UnregisterPlugin(CreateInstance);
}
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