[Lldb-commits] [lldb] [lldb] Merge/unify ABI-provided AArch64 unwind plans (PR #139545)
Pavel Labath via lldb-commits
lldb-commits at lists.llvm.org
Mon May 12 07:10:22 PDT 2025
https://github.com/labath updated https://github.com/llvm/llvm-project/pull/139545
>From 2aa2fd0d0777bd0bcdd1b627c2c3d306b79512c4 Mon Sep 17 00:00:00 2001
From: Pavel Labath <pavel at labath.sk>
Date: Mon, 12 May 2025 04:38:05 -0700
Subject: [PATCH] [lldb] Merge/unify ABI-provided AArch64 unwind plans
The macos and sysv ABIs return functionally equivalent unwind plans, so they
can be implemented in the base AArch64 class. The only difference between them
was that the macos plan provided a "pc=lr" rule whereas the sysv plan called
SetReturnAddressRegister (which causes the unwind machinery to act as if that
rule was present). This difference was enough to cause
`CompareUnwindPlansForIdenticalInitialPCLocation` to return a different value
and break the (temporarily reverted) TestUnwindFramelessFaulted test.
While merging the two functions, I couldn't help myself from simplifying them
to use the generic register number schemes -- which exposed another bug in
CompareUnwindPlansForIdenticalInitialPCLocation, namely that it was expecting
all unwind plans to use the LLDB numbering scheme. This patch fixes that as
well.
---
.../source/Plugins/ABI/AArch64/ABIAArch64.cpp | 42 +++++++++++++++++
lldb/source/Plugins/ABI/AArch64/ABIAArch64.h | 3 ++
.../Plugins/ABI/AArch64/ABIMacOSX_arm64.cpp | 45 -------------------
.../Plugins/ABI/AArch64/ABIMacOSX_arm64.h | 4 --
.../Plugins/ABI/AArch64/ABISysV_arm64.cpp | 44 ------------------
.../Plugins/ABI/AArch64/ABISysV_arm64.h | 4 --
lldb/source/Symbol/FuncUnwinders.cpp | 39 ++++++++--------
7 files changed, 63 insertions(+), 118 deletions(-)
diff --git a/lldb/source/Plugins/ABI/AArch64/ABIAArch64.cpp b/lldb/source/Plugins/ABI/AArch64/ABIAArch64.cpp
index 7d8d0a4d3d671..3bafb21f7c33a 100644
--- a/lldb/source/Plugins/ABI/AArch64/ABIAArch64.cpp
+++ b/lldb/source/Plugins/ABI/AArch64/ABIAArch64.cpp
@@ -19,6 +19,7 @@
#include <optional>
using namespace lldb;
+using namespace lldb_private;
LLDB_PLUGIN_DEFINE(ABIAArch64)
@@ -200,3 +201,44 @@ void ABIAArch64::AugmentRegisterInfo(
lldb::eEncodingIEEE754, lldb::eFormatFloat);
}
}
+
+UnwindPlanSP ABIAArch64::CreateFunctionEntryUnwindPlan() {
+ UnwindPlan::Row row;
+
+ // Our previous Call Frame Address is the stack pointer
+ row.GetCFAValue().SetIsRegisterPlusOffset(LLDB_REGNUM_GENERIC_SP, 0);
+
+ // Our previous PC is in the LR, all other registers are the same.
+ row.SetRegisterLocationToRegister(LLDB_REGNUM_GENERIC_PC,
+ LLDB_REGNUM_GENERIC_RA, true);
+
+ auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindGeneric);
+ plan_sp->AppendRow(std::move(row));
+ plan_sp->SetSourceName("arm64 at-func-entry default");
+ plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
+ plan_sp->SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
+ plan_sp->SetUnwindPlanForSignalTrap(eLazyBoolNo);
+ return plan_sp;
+}
+
+UnwindPlanSP ABIAArch64::CreateDefaultUnwindPlan() {
+ UnwindPlan::Row row;
+ const int32_t ptr_size = 8;
+
+ row.GetCFAValue().SetIsRegisterPlusOffset(LLDB_REGNUM_GENERIC_FP,
+ 2 * ptr_size);
+ row.SetUnspecifiedRegistersAreUndefined(true);
+
+ row.SetRegisterLocationToAtCFAPlusOffset(LLDB_REGNUM_GENERIC_FP,
+ ptr_size * -2, true);
+ row.SetRegisterLocationToAtCFAPlusOffset(LLDB_REGNUM_GENERIC_PC,
+ ptr_size * -1, true);
+
+ auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindGeneric);
+ plan_sp->AppendRow(std::move(row));
+ plan_sp->SetSourceName("arm64 default unwind plan");
+ plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
+ plan_sp->SetUnwindPlanValidAtAllInstructions(eLazyBoolNo);
+ plan_sp->SetUnwindPlanForSignalTrap(eLazyBoolNo);
+ return plan_sp;
+}
diff --git a/lldb/source/Plugins/ABI/AArch64/ABIAArch64.h b/lldb/source/Plugins/ABI/AArch64/ABIAArch64.h
index 52e42f1260a83..53702f4da580d 100644
--- a/lldb/source/Plugins/ABI/AArch64/ABIAArch64.h
+++ b/lldb/source/Plugins/ABI/AArch64/ABIAArch64.h
@@ -19,6 +19,9 @@ class ABIAArch64 : public lldb_private::MCBasedABI {
lldb::addr_t FixCodeAddress(lldb::addr_t pc) override;
lldb::addr_t FixDataAddress(lldb::addr_t pc) override;
+ lldb::UnwindPlanSP CreateFunctionEntryUnwindPlan() override;
+ lldb::UnwindPlanSP CreateDefaultUnwindPlan() override;
+
protected:
virtual lldb::addr_t FixAddress(lldb::addr_t pc, lldb::addr_t mask) {
return pc;
diff --git a/lldb/source/Plugins/ABI/AArch64/ABIMacOSX_arm64.cpp b/lldb/source/Plugins/ABI/AArch64/ABIMacOSX_arm64.cpp
index f86ab8cbb1195..094e0523a4edf 100644
--- a/lldb/source/Plugins/ABI/AArch64/ABIMacOSX_arm64.cpp
+++ b/lldb/source/Plugins/ABI/AArch64/ABIMacOSX_arm64.cpp
@@ -17,7 +17,6 @@
#include "lldb/Core/Module.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/Value.h"
-#include "lldb/Symbol/UnwindPlan.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/Target.h"
@@ -30,8 +29,6 @@
#include "lldb/Utility/Status.h"
#include "lldb/ValueObject/ValueObjectConstResult.h"
-#include "Utility/ARM64_DWARF_Registers.h"
-
using namespace lldb;
using namespace lldb_private;
@@ -344,48 +341,6 @@ ABIMacOSX_arm64::SetReturnValueObject(lldb::StackFrameSP &frame_sp,
return error;
}
-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;
-
- UnwindPlan::Row row;
-
- // Our previous Call Frame Address is the stack pointer
- row.GetCFAValue().SetIsRegisterPlusOffset(sp_reg_num, 0);
-
- // Our previous PC is in the LR, all other registers are the same.
- row.SetRegisterLocationToRegister(pc_reg_num, lr_reg_num, true);
-
- auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindDWARF);
- plan_sp->AppendRow(std::move(row));
- plan_sp->SetSourceName("arm64 at-func-entry default");
- plan_sp->SetSourcedFromCompiler(eLazyBoolNo);
- return plan_sp;
-}
-
-UnwindPlanSP ABIMacOSX_arm64::CreateDefaultUnwindPlan() {
- uint32_t fp_reg_num = arm64_dwarf::fp;
- uint32_t pc_reg_num = arm64_dwarf::pc;
-
- UnwindPlan::Row row;
- const int32_t ptr_size = 8;
-
- row.GetCFAValue().SetIsRegisterPlusOffset(fp_reg_num, 2 * ptr_size);
- row.SetUnspecifiedRegistersAreUndefined(true);
-
- row.SetRegisterLocationToAtCFAPlusOffset(fp_reg_num, ptr_size * -2, true);
- row.SetRegisterLocationToAtCFAPlusOffset(pc_reg_num, ptr_size * -1, true);
-
- auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindDWARF);
- plan_sp->AppendRow(std::move(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
// registers x19 through x28 and sp are callee preserved. v8-v15 are non-
// volatile (and specifically only the lower 8 bytes of these regs), the rest
diff --git a/lldb/source/Plugins/ABI/AArch64/ABIMacOSX_arm64.h b/lldb/source/Plugins/ABI/AArch64/ABIMacOSX_arm64.h
index 94a60327c6181..c8851709f50ad 100644
--- a/lldb/source/Plugins/ABI/AArch64/ABIMacOSX_arm64.h
+++ b/lldb/source/Plugins/ABI/AArch64/ABIMacOSX_arm64.h
@@ -27,10 +27,6 @@ class ABIMacOSX_arm64 : public ABIAArch64 {
bool GetArgumentValues(lldb_private::Thread &thread,
lldb_private::ValueList &values) const override;
- lldb::UnwindPlanSP CreateFunctionEntryUnwindPlan() override;
-
- lldb::UnwindPlanSP CreateDefaultUnwindPlan() override;
-
bool RegisterIsVolatile(const lldb_private::RegisterInfo *reg_info) override;
// The arm64 ABI requires that stack frames be 16 byte aligned.
diff --git a/lldb/source/Plugins/ABI/AArch64/ABISysV_arm64.cpp b/lldb/source/Plugins/ABI/AArch64/ABISysV_arm64.cpp
index 6e07c0982be0e..aa9c20b6bb2cf 100644
--- a/lldb/source/Plugins/ABI/AArch64/ABISysV_arm64.cpp
+++ b/lldb/source/Plugins/ABI/AArch64/ABISysV_arm64.cpp
@@ -30,8 +30,6 @@
#include "lldb/Utility/Status.h"
#include "lldb/ValueObject/ValueObjectConstResult.h"
-#include "Utility/ARM64_DWARF_Registers.h"
-
using namespace lldb;
using namespace lldb_private;
@@ -385,48 +383,6 @@ Status ABISysV_arm64::SetReturnValueObject(lldb::StackFrameSP &frame_sp,
return error;
}
-UnwindPlanSP ABISysV_arm64::CreateFunctionEntryUnwindPlan() {
- uint32_t lr_reg_num = arm64_dwarf::lr;
- uint32_t sp_reg_num = arm64_dwarf::sp;
-
- UnwindPlan::Row row;
-
- // Our previous Call Frame Address is the stack pointer, all other registers
- // are the same.
- row.GetCFAValue().SetIsRegisterPlusOffset(sp_reg_num, 0);
-
- auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindDWARF);
- plan_sp->AppendRow(std::move(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;
-}
-
-UnwindPlanSP ABISysV_arm64::CreateDefaultUnwindPlan() {
- uint32_t fp_reg_num = arm64_dwarf::fp;
- uint32_t pc_reg_num = arm64_dwarf::pc;
-
- UnwindPlan::Row row;
- const int32_t ptr_size = 8;
-
- row.GetCFAValue().SetIsRegisterPlusOffset(fp_reg_num, 2 * ptr_size);
- row.SetUnspecifiedRegistersAreUndefined(true);
-
- row.SetRegisterLocationToAtCFAPlusOffset(fp_reg_num, ptr_size * -2, true);
- row.SetRegisterLocationToAtCFAPlusOffset(pc_reg_num, ptr_size * -1, true);
-
- auto plan_sp = std::make_shared<UnwindPlan>(eRegisterKindDWARF);
- plan_sp->AppendRow(std::move(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
// registers x19 through x28 and sp are callee preserved. v8-v15 are non-
// volatile (and specifically only the lower 8 bytes of these regs), the rest
diff --git a/lldb/source/Plugins/ABI/AArch64/ABISysV_arm64.h b/lldb/source/Plugins/ABI/AArch64/ABISysV_arm64.h
index 2b8e608d4caab..213fbf7417b2c 100644
--- a/lldb/source/Plugins/ABI/AArch64/ABISysV_arm64.h
+++ b/lldb/source/Plugins/ABI/AArch64/ABISysV_arm64.h
@@ -30,10 +30,6 @@ class ABISysV_arm64 : public ABIAArch64 {
SetReturnValueObject(lldb::StackFrameSP &frame_sp,
lldb::ValueObjectSP &new_value) override;
- lldb::UnwindPlanSP CreateFunctionEntryUnwindPlan() override;
-
- lldb::UnwindPlanSP CreateDefaultUnwindPlan() override;
-
bool RegisterIsVolatile(const lldb_private::RegisterInfo *reg_info) override;
// The arm64 ABI requires that stack frames be 16 byte aligned.
diff --git a/lldb/source/Symbol/FuncUnwinders.cpp b/lldb/source/Symbol/FuncUnwinders.cpp
index faec24cde7fdd..12a6d101d9930 100644
--- a/lldb/source/Symbol/FuncUnwinders.cpp
+++ b/lldb/source/Symbol/FuncUnwinders.cpp
@@ -365,33 +365,30 @@ FuncUnwinders::GetAssemblyUnwindPlan(Target &target, Thread &thread) {
LazyBool FuncUnwinders::CompareUnwindPlansForIdenticalInitialPCLocation(
Thread &thread, const std::shared_ptr<const UnwindPlan> &a,
const std::shared_ptr<const UnwindPlan> &b) {
- LazyBool plans_are_identical = eLazyBoolCalculate;
+ if (!a || !b)
+ return eLazyBoolCalculate;
- RegisterNumber pc_reg(thread, eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
- uint32_t pc_reg_lldb_regnum = pc_reg.GetAsKind(eRegisterKindLLDB);
+ const UnwindPlan::Row *a_first_row = a->GetRowAtIndex(0);
+ const UnwindPlan::Row *b_first_row = b->GetRowAtIndex(0);
+ if (!a_first_row || !b_first_row)
+ return eLazyBoolCalculate;
- if (a && b) {
- const UnwindPlan::Row *a_first_row = a->GetRowAtIndex(0);
- const UnwindPlan::Row *b_first_row = b->GetRowAtIndex(0);
+ RegisterNumber pc_reg(thread, eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC);
+ uint32_t a_pc_regnum = pc_reg.GetAsKind(a->GetRegisterKind());
+ uint32_t b_pc_regnum = pc_reg.GetAsKind(b->GetRegisterKind());
- if (a_first_row && b_first_row) {
- UnwindPlan::Row::AbstractRegisterLocation a_pc_regloc;
- UnwindPlan::Row::AbstractRegisterLocation b_pc_regloc;
+ UnwindPlan::Row::AbstractRegisterLocation a_pc_regloc;
+ UnwindPlan::Row::AbstractRegisterLocation b_pc_regloc;
- a_first_row->GetRegisterInfo(pc_reg_lldb_regnum, a_pc_regloc);
- b_first_row->GetRegisterInfo(pc_reg_lldb_regnum, b_pc_regloc);
+ a_first_row->GetRegisterInfo(a_pc_regnum, a_pc_regloc);
+ b_first_row->GetRegisterInfo(b_pc_regnum, b_pc_regloc);
- plans_are_identical = eLazyBoolYes;
+ if (a_first_row->GetCFAValue() != b_first_row->GetCFAValue())
+ return eLazyBoolNo;
+ if (a_pc_regloc != b_pc_regloc)
+ return eLazyBoolNo;
- if (a_first_row->GetCFAValue() != b_first_row->GetCFAValue()) {
- plans_are_identical = eLazyBoolNo;
- }
- if (a_pc_regloc != b_pc_regloc) {
- plans_are_identical = eLazyBoolNo;
- }
- }
- }
- return plans_are_identical;
+ return eLazyBoolYes;
}
std::shared_ptr<const UnwindPlan>
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