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[lldb] Modernize ABI-based unwind plan creation #128505

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Feb 26, 2025
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[lldb] Modernize ABI-based unwind plan creation #128505

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5 changes: 5 additions & 0 deletions lldb/include/lldb/Symbol/UnwindPlan.h
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Original file line number Diff line number Diff line change
Expand Up @@ -450,6 +450,11 @@ class UnwindPlan {
for (const RowSP &row_sp : rhs.m_row_list)
m_row_list.emplace_back(new Row(*row_sp));
}
UnwindPlan(UnwindPlan &&rhs) = default;
UnwindPlan &operator=(const UnwindPlan &rhs) {
return *this = UnwindPlan(rhs); // NB: moving from a temporary (deep) copy
}
UnwindPlan &operator=(UnwindPlan &&) = default;

~UnwindPlan() = default;

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5 changes: 3 additions & 2 deletions lldb/include/lldb/Target/ABI.h
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Expand Up @@ -13,6 +13,7 @@
#include "lldb/Symbol/UnwindPlan.h"
#include "lldb/Target/DynamicRegisterInfo.h"
#include "lldb/Utility/Status.h"
#include "lldb/lldb-forward.h"
#include "lldb/lldb-private.h"

#include "llvm/ADT/ArrayRef.h"
Expand Down Expand Up @@ -96,9 +97,9 @@ class ABI : public PluginInterface {
lldb::ProcessSP GetProcessSP() const { return m_process_wp.lock(); }

public:
virtual bool CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) = 0;
virtual lldb::UnwindPlanSP CreateFunctionEntryUnwindPlan() = 0;

virtual bool CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) = 0;
virtual lldb::UnwindPlanSP CreateDefaultUnwindPlan() = 0;

virtual bool RegisterIsVolatile(const RegisterInfo *reg_info) = 0;

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14 changes: 6 additions & 8 deletions lldb/source/Commands/CommandObjectTarget.cpp
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Expand Up @@ -3763,20 +3763,18 @@ class CommandObjectTargetModulesShowUnwind : public CommandObjectParsed {

ABISP abi_sp = process->GetABI();
if (abi_sp) {
UnwindPlan arch_default(lldb::eRegisterKindGeneric);
if (abi_sp->CreateDefaultUnwindPlan(arch_default)) {
if (UnwindPlanSP plan_sp = abi_sp->CreateDefaultUnwindPlan()) {
result.GetOutputStream().Printf("Arch default UnwindPlan:\n");
arch_default.Dump(result.GetOutputStream(), thread.get(),
LLDB_INVALID_ADDRESS);
plan_sp->Dump(result.GetOutputStream(), thread.get(),
LLDB_INVALID_ADDRESS);
result.GetOutputStream().Printf("\n");
}

UnwindPlan arch_entry(lldb::eRegisterKindGeneric);
if (abi_sp->CreateFunctionEntryUnwindPlan(arch_entry)) {
if (UnwindPlanSP plan_sp = abi_sp->CreateFunctionEntryUnwindPlan()) {
result.GetOutputStream().Printf(
"Arch default at entry point UnwindPlan:\n");
arch_entry.Dump(result.GetOutputStream(), thread.get(),
LLDB_INVALID_ADDRESS);
plan_sp->Dump(result.GetOutputStream(), thread.get(),
LLDB_INVALID_ADDRESS);
result.GetOutputStream().Printf("\n");
}
}
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38 changes: 15 additions & 23 deletions lldb/source/Plugins/ABI/AArch64/ABIMacOSX_arm64.cpp
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Expand Up @@ -343,10 +343,7 @@ ABIMacOSX_arm64::SetReturnValueObject(lldb::StackFrameSP &frame_sp,
return error;
}

bool ABIMacOSX_arm64::CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) {
unwind_plan.Clear();
unwind_plan.SetRegisterKind(eRegisterKindDWARF);

UnwindPlanSP ABIMacOSX_arm64::CreateFunctionEntryUnwindPlan() {
uint32_t lr_reg_num = arm64_dwarf::lr;
uint32_t sp_reg_num = arm64_dwarf::sp;
uint32_t pc_reg_num = arm64_dwarf::pc;
Expand All @@ -356,23 +353,17 @@ bool ABIMacOSX_arm64::CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) {
// Our previous Call Frame Address is the stack pointer
row->GetCFAValue().SetIsRegisterPlusOffset(sp_reg_num, 0);

// Our previous PC is in the LR
// Our previous PC is in the LR, all other registers are the same.
row->SetRegisterLocationToRegister(pc_reg_num, lr_reg_num, true);

unwind_plan.AppendRow(row);

// All other registers are the same.

unwind_plan.SetSourceName("arm64 at-func-entry default");
unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);

return true;
auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindDWARF);
plan_sp->AppendRow(row);
plan_sp->SetSourceName("arm64 at-func-entry default");
plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
return plan_sp;
}

bool ABIMacOSX_arm64::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
unwind_plan.Clear();
unwind_plan.SetRegisterKind(eRegisterKindDWARF);

UnwindPlanSP ABIMacOSX_arm64::CreateDefaultUnwindPlan() {
uint32_t fp_reg_num = arm64_dwarf::fp;
uint32_t pc_reg_num = arm64_dwarf::pc;

Expand All @@ -386,12 +377,13 @@ bool ABIMacOSX_arm64::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
row->SetRegisterLocationToAtCFAPlusOffset(fp_reg_num, ptr_size * -2, true);
row->SetRegisterLocationToAtCFAPlusOffset(pc_reg_num, ptr_size * -1, true);

unwind_plan.AppendRow(row);
unwind_plan.SetSourceName("arm64-apple-darwin default unwind plan");
unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);
unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
unwind_plan.SetUnwindPlanForSignalTrap(eLazyBoolNo);
return true;
auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindDWARF);
plan_sp->AppendRow(row);
plan_sp->SetSourceName("arm64-apple-darwin default unwind plan");
plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
plan_sp->SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
plan_sp->SetUnwindPlanForSignalTrap(eLazyBoolNo);
return plan_sp;
}

// AAPCS64 (Procedure Call Standard for the ARM 64-bit Architecture) says
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5 changes: 2 additions & 3 deletions lldb/source/Plugins/ABI/AArch64/ABIMacOSX_arm64.h
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Expand Up @@ -27,10 +27,9 @@ class ABIMacOSX_arm64 : public ABIAArch64 {
bool GetArgumentValues(lldb_private::Thread &thread,
lldb_private::ValueList &values) const override;

bool
CreateFunctionEntryUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
lldb::UnwindPlanSP CreateFunctionEntryUnwindPlan() override;

bool CreateDefaultUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
lldb::UnwindPlanSP CreateDefaultUnwindPlan() override;

bool RegisterIsVolatile(const lldb_private::RegisterInfo *reg_info) override;

Expand Down
46 changes: 19 additions & 27 deletions lldb/source/Plugins/ABI/AArch64/ABISysV_arm64.cpp
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Expand Up @@ -391,35 +391,27 @@ Status ABISysV_arm64::SetReturnValueObject(lldb::StackFrameSP &frame_sp,
return error;
}

bool ABISysV_arm64::CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) {
unwind_plan.Clear();
unwind_plan.SetRegisterKind(eRegisterKindDWARF);

UnwindPlanSP ABISysV_arm64::CreateFunctionEntryUnwindPlan() {
uint32_t lr_reg_num = arm64_dwarf::lr;
uint32_t sp_reg_num = arm64_dwarf::sp;

UnwindPlan::RowSP row(new UnwindPlan::Row);

// Our previous Call Frame Address is the stack pointer
// Our previous Call Frame Address is the stack pointer, all other registers
// are the same.
row->GetCFAValue().SetIsRegisterPlusOffset(sp_reg_num, 0);

unwind_plan.AppendRow(row);
unwind_plan.SetReturnAddressRegister(lr_reg_num);

// All other registers are the same.

unwind_plan.SetSourceName("arm64 at-func-entry default");
unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);
unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
unwind_plan.SetUnwindPlanForSignalTrap(eLazyBoolNo);

return true;
auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindDWARF);
plan_sp->AppendRow(row);
plan_sp->SetReturnAddressRegister(lr_reg_num);
plan_sp->SetSourceName("arm64 at-func-entry default");
plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
plan_sp->SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
plan_sp->SetUnwindPlanForSignalTrap(eLazyBoolNo);
return plan_sp;
}

bool ABISysV_arm64::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
unwind_plan.Clear();
unwind_plan.SetRegisterKind(eRegisterKindDWARF);

UnwindPlanSP ABISysV_arm64::CreateDefaultUnwindPlan() {
uint32_t fp_reg_num = arm64_dwarf::fp;
uint32_t pc_reg_num = arm64_dwarf::pc;

Expand All @@ -433,13 +425,13 @@ bool ABISysV_arm64::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
row->SetRegisterLocationToAtCFAPlusOffset(fp_reg_num, ptr_size * -2, true);
row->SetRegisterLocationToAtCFAPlusOffset(pc_reg_num, ptr_size * -1, true);

unwind_plan.AppendRow(row);
unwind_plan.SetSourceName("arm64 default unwind plan");
unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);
unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
unwind_plan.SetUnwindPlanForSignalTrap(eLazyBoolNo);

return true;
auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindDWARF);
plan_sp->AppendRow(row);
plan_sp->SetSourceName("arm64 default unwind plan");
plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
plan_sp->SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
plan_sp->SetUnwindPlanForSignalTrap(eLazyBoolNo);
return plan_sp;
}

// AAPCS64 (Procedure Call Standard for the ARM 64-bit Architecture) says
Expand Down
5 changes: 2 additions & 3 deletions lldb/source/Plugins/ABI/AArch64/ABISysV_arm64.h
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Expand Up @@ -30,10 +30,9 @@ class ABISysV_arm64 : public ABIAArch64 {
SetReturnValueObject(lldb::StackFrameSP &frame_sp,
lldb::ValueObjectSP &new_value) override;

bool
CreateFunctionEntryUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
lldb::UnwindPlanSP CreateFunctionEntryUnwindPlan() override;

bool CreateDefaultUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
lldb::UnwindPlanSP CreateDefaultUnwindPlan() override;

bool RegisterIsVolatile(const lldb_private::RegisterInfo *reg_info) override;

Expand Down
22 changes: 8 additions & 14 deletions lldb/source/Plugins/ABI/ARC/ABISysV_arc.cpp
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Expand Up @@ -555,29 +555,23 @@ ValueObjectSP ABISysV_arc::GetReturnValueObjectImpl(Thread &thread,
value, ConstString(""));
}

bool ABISysV_arc::CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) {
unwind_plan.Clear();
unwind_plan.SetRegisterKind(eRegisterKindDWARF);

UnwindPlanSP ABISysV_arc::CreateFunctionEntryUnwindPlan() {
UnwindPlan::RowSP row(new UnwindPlan::Row);

// Our Call Frame Address is the stack pointer value.
row->GetCFAValue().SetIsRegisterPlusOffset(dwarf::sp, 0);

// The previous PC is in the BLINK.
// The previous PC is in the BLINK, all other registers are the same.
row->SetRegisterLocationToRegister(dwarf::pc, dwarf::blink, true);
unwind_plan.AppendRow(row);

// All other registers are the same.
unwind_plan.SetSourceName("arc at-func-entry default");
unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);

return true;
auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindDWARF);
plan_sp->AppendRow(row);
plan_sp->SetSourceName("arc at-func-entry default");
plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
return plan_sp;
}

bool ABISysV_arc::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
return false;
}
UnwindPlanSP ABISysV_arc::CreateDefaultUnwindPlan() { return nullptr; }

bool ABISysV_arc::RegisterIsVolatile(const RegisterInfo *reg_info) {
if (nullptr == reg_info)
Expand Down
5 changes: 2 additions & 3 deletions lldb/source/Plugins/ABI/ARC/ABISysV_arc.h
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Expand Up @@ -49,10 +49,9 @@ class ABISysV_arc : public lldb_private::RegInfoBasedABI {
lldb::ValueObjectSP GetReturnValueObjectImpl(lldb_private::Thread &thread,
llvm::Type &type) const override;

bool
CreateFunctionEntryUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
lldb::UnwindPlanSP CreateFunctionEntryUnwindPlan() override;

bool CreateDefaultUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
lldb::UnwindPlanSP CreateDefaultUnwindPlan() override;

bool RegisterIsVolatile(const lldb_private::RegisterInfo *reg_info) override;

Expand Down
38 changes: 15 additions & 23 deletions lldb/source/Plugins/ABI/ARM/ABIMacOSX_arm.cpp
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Expand Up @@ -1781,10 +1781,7 @@ Status ABIMacOSX_arm::SetReturnValueObject(lldb::StackFrameSP &frame_sp,
return error;
}

bool ABIMacOSX_arm::CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) {
unwind_plan.Clear();
unwind_plan.SetRegisterKind(eRegisterKindDWARF);

UnwindPlanSP ABIMacOSX_arm::CreateFunctionEntryUnwindPlan() {
uint32_t lr_reg_num = dwarf_lr;
uint32_t sp_reg_num = dwarf_sp;
uint32_t pc_reg_num = dwarf_pc;
Expand All @@ -1794,22 +1791,17 @@ bool ABIMacOSX_arm::CreateFunctionEntryUnwindPlan(UnwindPlan &unwind_plan) {
// Our Call Frame Address is the stack pointer value
row->GetCFAValue().SetIsRegisterPlusOffset(sp_reg_num, 0);

// The previous PC is in the LR
// The previous PC is in the LR, all other registers are the same.
row->SetRegisterLocationToRegister(pc_reg_num, lr_reg_num, true);
unwind_plan.AppendRow(row);

// All other registers are the same.

unwind_plan.SetSourceName("arm at-func-entry default");
unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);

return true;
auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindDWARF);
plan_sp->AppendRow(row);
plan_sp->SetSourceName("arm at-func-entry default");
plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
return plan_sp;
}

bool ABIMacOSX_arm::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
unwind_plan.Clear();
unwind_plan.SetRegisterKind(eRegisterKindDWARF);

UnwindPlanSP ABIMacOSX_arm::CreateDefaultUnwindPlan() {
uint32_t fp_reg_num =
dwarf_r7; // apple uses r7 for all frames. Normal arm uses r11
uint32_t pc_reg_num = dwarf_pc;
Expand All @@ -1824,13 +1816,13 @@ bool ABIMacOSX_arm::CreateDefaultUnwindPlan(UnwindPlan &unwind_plan) {
row->SetRegisterLocationToAtCFAPlusOffset(fp_reg_num, ptr_size * -2, true);
row->SetRegisterLocationToAtCFAPlusOffset(pc_reg_num, ptr_size * -1, true);

unwind_plan.AppendRow(row);
unwind_plan.SetSourceName("arm-apple-ios default unwind plan");
unwind_plan.SetSourcedFromCompiler(eLazyBoolNo);
unwind_plan.SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
unwind_plan.SetUnwindPlanForSignalTrap(eLazyBoolNo);

return true;
auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindDWARF);
plan_sp->AppendRow(row);
plan_sp->SetSourceName("arm-apple-ios default unwind plan");
plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
plan_sp->SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
plan_sp->SetUnwindPlanForSignalTrap(eLazyBoolNo);
return plan_sp;
}

// cf. "ARMv6 Function Calling Conventions"
Expand Down
5 changes: 2 additions & 3 deletions lldb/source/Plugins/ABI/ARM/ABIMacOSX_arm.h
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Expand Up @@ -29,10 +29,9 @@ class ABIMacOSX_arm : public lldb_private::RegInfoBasedABI {
SetReturnValueObject(lldb::StackFrameSP &frame_sp,
lldb::ValueObjectSP &new_value) override;

bool
CreateFunctionEntryUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
lldb::UnwindPlanSP CreateFunctionEntryUnwindPlan() override;

bool CreateDefaultUnwindPlan(lldb_private::UnwindPlan &unwind_plan) override;
lldb::UnwindPlanSP CreateDefaultUnwindPlan() override;

bool RegisterIsVolatile(const lldb_private::RegisterInfo *reg_info) override;

Expand Down
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