https://github.com/dsandersllvm updated
https://github.com/llvm/llvm-project/pull/150732
>From bd27929645928939f319dc915da1a4636e4d317d Mon Sep 17 00:00:00 2001
From: Daniel Sanders <daniel_l_sand...@apple.com>
Date: Wed, 28 Aug 2024 19:02:21 -0700
Subject: [PATCH 1/6] [lldb] Implement DW_CFA_val_offset and
DW_CFA_val_offset_sf
The test for this is artificial as I'm not aware of any upstream targets
that use DW_CFA_val_offset
RegisterContextUnwind::ReadFrameAddress now reports how it's attempting to
obtain the CFA unless all success/failure cases emit logs that clearly
identify the method it was attempting. Previously several of the existing
failure paths emit no message or a message that's indistinguishable from
those on other paths.
---
lldb/include/lldb/Symbol/UnwindPlan.h | 20 +++
lldb/include/lldb/Target/UnwindLLDB.h | 8 ++
lldb/source/Symbol/DWARFCallFrameInfo.cpp | 28 +++-
lldb/source/Symbol/UnwindPlan.cpp | 17 +++
lldb/source/Target/RegisterContextUnwind.cpp | 54 +++++++-
.../Symbol/TestDWARFCallFrameInfo.cpp | 124 ++++++++++++++++++
6 files changed, 248 insertions(+), 3 deletions(-)
diff --git a/lldb/include/lldb/Symbol/UnwindPlan.h
b/lldb/include/lldb/Symbol/UnwindPlan.h
index fe8081f83c590..9587f1312aa2e 100644
--- a/lldb/include/lldb/Symbol/UnwindPlan.h
+++ b/lldb/include/lldb/Symbol/UnwindPlan.h
@@ -67,6 +67,7 @@ class UnwindPlan {
atAFAPlusOffset, // reg = deref(AFA + offset)
isAFAPlusOffset, // reg = AFA + offset
inOtherRegister, // reg = other reg
+ isOtherRegisterPlusOffset, // reg = other reg + offset
atDWARFExpression, // reg = deref(eval(dwarf_expr))
isDWARFExpression, // reg = eval(dwarf_expr)
isConstant // reg = constant
@@ -102,6 +103,10 @@ class UnwindPlan {
bool IsInOtherRegister() const { return m_type == inOtherRegister; }
+ bool IsOtherRegisterPlusOffset() const {
+ return m_type == isOtherRegisterPlusOffset;
+ }
+
bool IsAtDWARFExpression() const { return m_type == atDWARFExpression; }
bool IsDWARFExpression() const { return m_type == isDWARFExpression; }
@@ -140,9 +145,17 @@ class UnwindPlan {
m_location.reg_num = reg_num;
}
+ void SetIsRegisterPlusOffset(uint32_t reg_num, int32_t offset = 0) {
+ m_type = isOtherRegisterPlusOffset;
+ m_location.reg_plus_offset.reg_num = reg_num;
+ m_location.reg_plus_offset.offset = offset;
+ }
+
uint32_t GetRegisterNumber() const {
if (m_type == inOtherRegister)
return m_location.reg_num;
+ if (m_type == isOtherRegisterPlusOffset)
+ return m_location.reg_plus_offset.reg_num;
return LLDB_INVALID_REGNUM;
}
@@ -156,6 +169,8 @@ class UnwindPlan {
case atAFAPlusOffset:
case isAFAPlusOffset:
return m_location.offset;
+ case inOtherRegister:
+ return m_location.reg_plus_offset.offset;
default:
return 0;
}
@@ -204,6 +219,11 @@ class UnwindPlan {
} expr;
// For m_type == isConstant
uint64_t constant_value;
+ // For m_type == inOtherRegisterPlusOffset
+ struct {
+ uint32_t reg_num;
+ int32_t offset;
+ } reg_plus_offset;
} m_location;
};
diff --git a/lldb/include/lldb/Target/UnwindLLDB.h
b/lldb/include/lldb/Target/UnwindLLDB.h
index f2f65e67a7640..88180b37fd93a 100644
--- a/lldb/include/lldb/Target/UnwindLLDB.h
+++ b/lldb/include/lldb/Target/UnwindLLDB.h
@@ -49,6 +49,9 @@ class UnwindLLDB : public lldb_private::Unwind {
// target mem (target_memory_location)
eRegisterInRegister, // register is available in a (possible other)
// register (register_number)
+ eRegisterIsRegisterPlusOffset, // register is available in a (possible
+ // other) register (register_number) with
+ // an offset applied
eRegisterSavedAtHostMemoryLocation, // register is saved at a word in
// lldb's address space
eRegisterValueInferred, // register val was computed (and is in
@@ -64,6 +67,11 @@ class UnwindLLDB : public lldb_private::Unwind {
void *host_memory_location;
uint64_t inferred_value; // eRegisterValueInferred - e.g. stack pointer
==
// cfa + offset
+ struct {
+ uint32_t
+ register_number; // in eRegisterKindLLDB register numbering system
+ uint64_t offset;
+ } reg_plus_offset;
} location;
};
diff --git a/lldb/source/Symbol/DWARFCallFrameInfo.cpp
b/lldb/source/Symbol/DWARFCallFrameInfo.cpp
index a2d748adad64a..2f8f9e9182fb2 100644
--- a/lldb/source/Symbol/DWARFCallFrameInfo.cpp
+++ b/lldb/source/Symbol/DWARFCallFrameInfo.cpp
@@ -766,8 +766,32 @@ DWARFCallFrameInfo::ParseFDE(dw_offset_t dwarf_offset,
break;
}
- case DW_CFA_val_offset: // 0x14
- case DW_CFA_val_offset_sf: // 0x15
+ case DW_CFA_val_offset: { // 0x14
+ // takes two unsigned LEB128 operands representing a register number
+ // and a factored offset. The required action is to change the rule
+ // for the register indicated by the register number to be a
+ // val_offset(N) rule where the value of N is factored_offset*
+ // data_alignment_factor
+ uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
+ int32_t op_offset =
+ (int32_t)m_cfi_data.GetULEB128(&offset) * data_align;
+ reg_location.SetIsCFAPlusOffset(op_offset);
+ row.SetRegisterInfo(reg_num, reg_location);
+ break;
+ }
+ case DW_CFA_val_offset_sf: { // 0x15
+ // takes two operands: an unsigned LEB128 value representing a
+ // register number and a signed LEB128 factored offset. This
+ // instruction is identical to DW_CFA_val_offset except that the
+ // second operand is signed and factored. The resulting offset is
+ // factored_offset* data_alignment_factor.
+ uint32_t reg_num = (uint32_t)m_cfi_data.GetULEB128(&offset);
+ int32_t op_offset =
+ (int32_t)m_cfi_data.GetSLEB128(&offset) * data_align;
+ reg_location.SetIsCFAPlusOffset(op_offset);
+ row.SetRegisterInfo(reg_num, reg_location);
+ break;
+ }
default:
break;
}
diff --git a/lldb/source/Symbol/UnwindPlan.cpp
b/lldb/source/Symbol/UnwindPlan.cpp
index 9245e52732061..93587568a7e64 100644
--- a/lldb/source/Symbol/UnwindPlan.cpp
+++ b/lldb/source/Symbol/UnwindPlan.cpp
@@ -42,6 +42,12 @@ bool UnwindPlan::Row::AbstractRegisterLocation::operator==(
case inOtherRegister:
return m_location.reg_num == rhs.m_location.reg_num;
+ case isOtherRegisterPlusOffset:
+ return m_location.reg_plus_offset.reg_num ==
+ rhs.m_location.reg_plus_offset.reg_num &&
+ m_location.reg_plus_offset.offset ==
+ rhs.m_location.reg_plus_offset.offset;
+
case atDWARFExpression:
case isDWARFExpression:
if (m_location.expr.length == rhs.m_location.expr.length)
@@ -145,6 +151,17 @@ void UnwindPlan::Row::AbstractRegisterLocation::Dump(
s.Printf("=reg(%u)", m_location.reg_num);
} break;
+ case isOtherRegisterPlusOffset: {
+ const RegisterInfo *other_reg_info = nullptr;
+ if (unwind_plan)
+ other_reg_info = unwind_plan->GetRegisterInfo(thread,
m_location.reg_num);
+ if (other_reg_info)
+ s.Printf("=%s", other_reg_info->name);
+ else
+ s.Printf("=reg(%u)+%u", m_location.reg_plus_offset.reg_num,
+ m_location.reg_plus_offset.offset);
+ } break;
+
case atDWARFExpression:
case isDWARFExpression: {
s.PutChar('=');
diff --git a/lldb/source/Target/RegisterContextUnwind.cpp
b/lldb/source/Target/RegisterContextUnwind.cpp
index 880300d0637fb..80345e6d3588c 100644
--- a/lldb/source/Target/RegisterContextUnwind.cpp
+++ b/lldb/source/Target/RegisterContextUnwind.cpp
@@ -1118,6 +1118,27 @@ bool
RegisterContextUnwind::ReadRegisterValueFromRegisterLocation(
success = GetNextFrame()->ReadRegister(other_reg_info, value);
}
} break;
+ case UnwindLLDB::ConcreteRegisterLocation::eRegisterIsRegisterPlusOffset: {
+ auto regnum = regloc.location.reg_plus_offset.register_number;
+ const RegisterInfo *other_reg_info =
+
GetRegisterInfoAtIndex(regloc.location.reg_plus_offset.register_number);
+
+ if (!other_reg_info)
+ return false;
+
+ if (IsFrameZero()) {
+ success =
+ m_thread.GetRegisterContext()->ReadRegister(other_reg_info, value);
+ } else {
+ success = GetNextFrame()->ReadRegister(other_reg_info, value);
+ }
+ if (success) {
+ UnwindLogMsg("read (%d)'s location", regnum);
+ value = value.GetAsUInt64(~0ull, &success) +
+ regloc.location.reg_plus_offset.offset;
+ UnwindLogMsg("success %s", success ? "yes" : "no");
+ }
+ } break;
case UnwindLLDB::ConcreteRegisterLocation::eRegisterValueInferred:
success =
value.SetUInt(regloc.location.inferred_value, reg_info->byte_size);
@@ -1164,6 +1185,7 @@ bool
RegisterContextUnwind::WriteRegisterValueToRegisterLocation(
success = GetNextFrame()->WriteRegister(other_reg_info, value);
}
} break;
+ case UnwindLLDB::ConcreteRegisterLocation::eRegisterIsRegisterPlusOffset:
case UnwindLLDB::ConcreteRegisterLocation::eRegisterValueInferred:
case UnwindLLDB::ConcreteRegisterLocation::eRegisterNotSaved:
break;
@@ -1633,6 +1655,30 @@ RegisterContextUnwind::SavedLocationForRegister(
return UnwindLLDB::RegisterSearchResult::eRegisterFound;
}
+ if (abs_regloc->IsOtherRegisterPlusOffset()) {
+ uint32_t unwindplan_regnum = abs_regloc->GetRegisterNumber();
+ int unwindplan_offset = abs_regloc->GetOffset();
+ RegisterNumber row_regnum(m_thread, abs_regkind, unwindplan_regnum);
+ if (row_regnum.GetAsKind(eRegisterKindLLDB) == LLDB_INVALID_REGNUM) {
+ UnwindLogMsg("could not supply caller's %s (%d) location - was saved in "
+ "another reg+offset but couldn't convert that regnum",
+ regnum.GetName(), regnum.GetAsKind(eRegisterKindLLDB));
+ return UnwindLLDB::RegisterSearchResult::eRegisterNotFound;
+ }
+ regloc.type =
+ UnwindLLDB::ConcreteRegisterLocation::eRegisterIsRegisterPlusOffset;
+ regloc.location.reg_plus_offset.register_number =
+ row_regnum.GetAsKind(eRegisterKindLLDB);
+ regloc.location.reg_plus_offset.offset = unwindplan_offset;
+ m_registers[regnum.GetAsKind(eRegisterKindLLDB)] = regloc;
+ UnwindLogMsg("supplying caller's register %s (%d), "
+ "from register %s (%d) plus offset %u",
+ regnum.GetName(), regnum.GetAsKind(eRegisterKindLLDB),
+ row_regnum.GetName(), row_regnum.GetAsKind(eRegisterKindLLDB),
+ unwindplan_offset);
+ return UnwindLLDB::RegisterSearchResult::eRegisterFound;
+ }
+
if (abs_regloc->IsDWARFExpression() || abs_regloc->IsAtDWARFExpression()) {
DataExtractor dwarfdata(abs_regloc->GetDWARFExpressionBytes(),
abs_regloc->GetDWARFExpressionLength(),
@@ -1959,6 +2005,7 @@ bool RegisterContextUnwind::ReadFrameAddress(
switch (fa.GetValueType()) {
case UnwindPlan::Row::FAValue::isRegisterDereferenced: {
+ UnwindLogMsg("CFA value via dereferencing reg");
RegisterNumber cfa_reg(m_thread, row_register_kind,
fa.GetRegisterNumber());
if (ReadGPRValue(cfa_reg, cfa_reg_contents)) {
@@ -1991,6 +2038,7 @@ bool RegisterContextUnwind::ReadFrameAddress(
break;
}
case UnwindPlan::Row::FAValue::isRegisterPlusOffset: {
+ UnwindLogMsg("CFA value via register plus offset");
RegisterNumber cfa_reg(m_thread, row_register_kind,
fa.GetRegisterNumber());
if (ReadGPRValue(cfa_reg, cfa_reg_contents)) {
@@ -2012,10 +2060,13 @@ bool RegisterContextUnwind::ReadFrameAddress(
address, cfa_reg.GetName(), cfa_reg.GetAsKind(eRegisterKindLLDB),
cfa_reg_contents, fa.GetOffset());
return true;
- }
+ } else
+ UnwindLogMsg("unable to read CFA register %s (%d)", cfa_reg.GetName(),
+ cfa_reg.GetAsKind(eRegisterKindLLDB));
break;
}
case UnwindPlan::Row::FAValue::isDWARFExpression: {
+ UnwindLogMsg("CFA value via DWARF expression");
ExecutionContext exe_ctx(m_thread.shared_from_this());
Process *process = exe_ctx.GetProcessPtr();
DataExtractor dwarfdata(fa.GetDWARFExpressionBytes(),
@@ -2042,6 +2093,7 @@ bool RegisterContextUnwind::ReadFrameAddress(
break;
}
case UnwindPlan::Row::FAValue::isRaSearch: {
+ UnwindLogMsg("CFA value via heuristic search");
Process &process = *m_thread.GetProcess();
lldb::addr_t return_address_hint = GetReturnAddressHint(fa.GetOffset());
if (return_address_hint == LLDB_INVALID_ADDRESS)
diff --git a/lldb/unittests/Symbol/TestDWARFCallFrameInfo.cpp
b/lldb/unittests/Symbol/TestDWARFCallFrameInfo.cpp
index c1dcab02227da..a75a4acd304b2 100644
--- a/lldb/unittests/Symbol/TestDWARFCallFrameInfo.cpp
+++ b/lldb/unittests/Symbol/TestDWARFCallFrameInfo.cpp
@@ -39,6 +39,7 @@ class DWARFCallFrameInfoTest : public testing::Test {
protected:
void TestBasic(DWARFCallFrameInfo::Type type, llvm::StringRef symbol);
+ void TestValOffset(DWARFCallFrameInfo::Type type, llvm::StringRef symbol);
};
namespace lldb_private {
@@ -256,3 +257,126 @@ TEST_F(DWARFCallFrameInfoTest, Basic_dwarf4) {
TEST_F(DWARFCallFrameInfoTest, Basic_eh) {
TestBasic(DWARFCallFrameInfo::EH, "eh_frame");
}
+
+static UnwindPlan::Row GetValOffsetExpectedRow0() {
+ UnwindPlan::Row row;
+ row.SetOffset(0);
+ row.GetCFAValue().SetIsRegisterPlusOffset(dwarf_rsp_x86_64, 16);
+ row.SetRegisterLocationToAtCFAPlusOffset(dwarf_rip_x86_64, -8, false);
+ row.SetRegisterLocationToIsCFAPlusOffset(dwarf_rbp_x86_64, -16, false);
+ return row;
+}
+
+void DWARFCallFrameInfoTest::TestValOffset(DWARFCallFrameInfo::Type type,
+ llvm::StringRef symbol) {
+ // This test is artificial as X86 does not use DW_CFA_val_offset but this
+ // test verifies that we can successfully interpret them if they do occur.
+ // Note the distinction between RBP and RIP in this part of the DWARF dump:
+ // 0x0: CFA=RSP+16: RBP=CFA-16, RIP=[CFA-8]
+ // Whereas RIP is stored in the memory CFA-8 points at, RBP is reconstructed
+ // from the CFA without any memory access.
+ auto ExpectedFile = TestFile::fromYaml(R"(
+--- !ELF
+FileHeader:
+ Class: ELFCLASS64
+ Data: ELFDATA2LSB
+ Type: ET_REL
+ Machine: EM_X86_64
+ SectionHeaderStringTable: .strtab
+Sections:
+ - Name: .text
+ Type: SHT_PROGBITS
+ Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
+ AddressAlign: 0x4
+ Content: 0F1F00
+ - Name: .debug_frame
+ Type: SHT_PROGBITS
+ AddressAlign: 0x8
+#00000000 00000014 ffffffff CIE
+# Format: DWARF32
+# Version: 4
+# Augmentation: ""
+# Address size: 8
+# Segment desc size: 0
+# Code alignment factor: 1
+# Data alignment factor: -8
+# Return address column: 16
+#
+# DW_CFA_def_cfa: RSP +8
+# DW_CFA_offset: RIP -8
+# DW_CFA_nop:
+# DW_CFA_nop:
+# DW_CFA_nop:
+# DW_CFA_nop:
+#
+# CFA=RSP+8: RIP=[CFA-8]
+#
+#00000018 0000001c 00000000 FDE cie=00000000 pc=00000000...00000003
+# Format: DWARF32
+# DW_CFA_def_cfa_offset: +16
+# DW_CFA_val_offset: RBP -16
+# DW_CFA_nop:
+# DW_CFA_nop:
+# DW_CFA_nop:
+#
+# 0x0: CFA=RSP+16: RBP=CFA-16, RIP=[CFA-8]
+ Content:
14000000FFFFFFFF040008000178100C07089001000000001C00000000000000000000000000000003000000000000000E10140602000000
+ - Name: .rela.debug_frame
+ Type: SHT_RELA
+ Flags: [ SHF_INFO_LINK ]
+ Link: .symtab
+ AddressAlign: 0x8
+ Info: .debug_frame
+ Relocations:
+ - Offset: 0x1C
+ Symbol: .debug_frame
+ Type: R_X86_64_32
+ - Offset: 0x20
+ Symbol: .text
+ Type: R_X86_64_64
+ - Type: SectionHeaderTable
+ Sections:
+ - Name: .strtab
+ - Name: .text
+ - Name: .debug_frame
+ - Name: .rela.debug_frame
+ - Name: .symtab
+Symbols:
+ - Name: .text
+ Type: STT_SECTION
+ Section: .text
+ - Name: debug_frame3
+ Section: .text
+ - Name: .debug_frame
+ Type: STT_SECTION
+ Section: .debug_frame
+...
+)");
+ ASSERT_THAT_EXPECTED(ExpectedFile, llvm::Succeeded());
+
+ auto module_sp = std::make_shared<Module>(ExpectedFile->moduleSpec());
+ SectionList *list = module_sp->GetSectionList();
+ ASSERT_NE(nullptr, list);
+
+ auto section_sp = list->FindSectionByType(type == DWARFCallFrameInfo::EH
+ ? eSectionTypeEHFrame
+ : eSectionTypeDWARFDebugFrame,
+ false);
+ ASSERT_NE(nullptr, section_sp);
+
+ DWARFCallFrameInfo cfi(*module_sp->GetObjectFile(), section_sp, type);
+
+ const Symbol *sym = module_sp->FindFirstSymbolWithNameAndType(
+ ConstString(symbol), eSymbolTypeAny);
+ ASSERT_NE(nullptr, sym);
+
+ std::unique_ptr<UnwindPlan> plan_up = cfi.GetUnwindPlan(sym->GetAddress());
+ ASSERT_TRUE(plan_up);
+ ASSERT_EQ(1, plan_up->GetRowCount());
+ EXPECT_THAT(plan_up->GetRowAtIndex(0),
testing::Pointee(GetValOffsetExpectedRow0()));
+}
+
+TEST_F(DWARFCallFrameInfoTest, ValOffset_dwarf3) {
+ TestValOffset(DWARFCallFrameInfo::DWARF, "debug_frame3");
+}
+
>From c9e9bbfbfca5a2221bf5bb0be32789a705241a50 Mon Sep 17 00:00:00 2001
From: Daniel Sanders <daniel_l_sand...@apple.com>
Date: Mon, 28 Jul 2025 09:06:34 -0700
Subject: [PATCH 2/6] fixup: formatting
---
lldb/include/lldb/Symbol/UnwindPlan.h | 26 +++++++++----------
.../Symbol/TestDWARFCallFrameInfo.cpp | 4 +--
2 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/lldb/include/lldb/Symbol/UnwindPlan.h
b/lldb/include/lldb/Symbol/UnwindPlan.h
index 9587f1312aa2e..7c562e6686023 100644
--- a/lldb/include/lldb/Symbol/UnwindPlan.h
+++ b/lldb/include/lldb/Symbol/UnwindPlan.h
@@ -57,20 +57,20 @@ class UnwindPlan {
class AbstractRegisterLocation {
public:
enum RestoreType {
- unspecified, // not specified, we may be able to assume this
- // is the same register. gcc doesn't specify all
- // initial values so we really don't know...
- undefined, // reg is not available, e.g. volatile reg
- same, // reg is unchanged
- atCFAPlusOffset, // reg = deref(CFA + offset)
- isCFAPlusOffset, // reg = CFA + offset
- atAFAPlusOffset, // reg = deref(AFA + offset)
- isAFAPlusOffset, // reg = AFA + offset
- inOtherRegister, // reg = other reg
+ unspecified, // not specified, we may be able to assume this
+ // is the same register. gcc doesn't specify all
+ // initial values so we really don't know...
+ undefined, // reg is not available, e.g. volatile reg
+ same, // reg is unchanged
+ atCFAPlusOffset, // reg = deref(CFA + offset)
+ isCFAPlusOffset, // reg = CFA + offset
+ atAFAPlusOffset, // reg = deref(AFA + offset)
+ isAFAPlusOffset, // reg = AFA + offset
+ inOtherRegister, // reg = other reg
isOtherRegisterPlusOffset, // reg = other reg + offset
- atDWARFExpression, // reg = deref(eval(dwarf_expr))
- isDWARFExpression, // reg = eval(dwarf_expr)
- isConstant // reg = constant
+ atDWARFExpression, // reg = deref(eval(dwarf_expr))
+ isDWARFExpression, // reg = eval(dwarf_expr)
+ isConstant // reg = constant
};
AbstractRegisterLocation() : m_location() {}
diff --git a/lldb/unittests/Symbol/TestDWARFCallFrameInfo.cpp
b/lldb/unittests/Symbol/TestDWARFCallFrameInfo.cpp
index a75a4acd304b2..e113b8ca99341 100644
--- a/lldb/unittests/Symbol/TestDWARFCallFrameInfo.cpp
+++ b/lldb/unittests/Symbol/TestDWARFCallFrameInfo.cpp
@@ -373,10 +373,10 @@ void
DWARFCallFrameInfoTest::TestValOffset(DWARFCallFrameInfo::Type type,
std::unique_ptr<UnwindPlan> plan_up = cfi.GetUnwindPlan(sym->GetAddress());
ASSERT_TRUE(plan_up);
ASSERT_EQ(1, plan_up->GetRowCount());
- EXPECT_THAT(plan_up->GetRowAtIndex(0),
testing::Pointee(GetValOffsetExpectedRow0()));
+ EXPECT_THAT(plan_up->GetRowAtIndex(0),
+ testing::Pointee(GetValOffsetExpectedRow0()));
}
TEST_F(DWARFCallFrameInfoTest, ValOffset_dwarf3) {
TestValOffset(DWARFCallFrameInfo::DWARF, "debug_frame3");
}
-
>From 7a0329fe6cc02f1ea057dccd09336b18968474b2 Mon Sep 17 00:00:00 2001
From: Daniel Sanders <daniel_l_sand...@apple.com>
Date: Mon, 28 Jul 2025 10:25:29 -0700
Subject: [PATCH 3/6] fixup: Remove unused code
---
lldb/include/lldb/Symbol/UnwindPlan.h | 20 ----------------
lldb/source/Symbol/UnwindPlan.cpp | 17 --------------
lldb/source/Target/RegisterContextUnwind.cpp | 24 --------------------
3 files changed, 61 deletions(-)
diff --git a/lldb/include/lldb/Symbol/UnwindPlan.h
b/lldb/include/lldb/Symbol/UnwindPlan.h
index 7c562e6686023..a38d36a69302d 100644
--- a/lldb/include/lldb/Symbol/UnwindPlan.h
+++ b/lldb/include/lldb/Symbol/UnwindPlan.h
@@ -67,7 +67,6 @@ class UnwindPlan {
atAFAPlusOffset, // reg = deref(AFA + offset)
isAFAPlusOffset, // reg = AFA + offset
inOtherRegister, // reg = other reg
- isOtherRegisterPlusOffset, // reg = other reg + offset
atDWARFExpression, // reg = deref(eval(dwarf_expr))
isDWARFExpression, // reg = eval(dwarf_expr)
isConstant // reg = constant
@@ -103,10 +102,6 @@ class UnwindPlan {
bool IsInOtherRegister() const { return m_type == inOtherRegister; }
- bool IsOtherRegisterPlusOffset() const {
- return m_type == isOtherRegisterPlusOffset;
- }
-
bool IsAtDWARFExpression() const { return m_type == atDWARFExpression; }
bool IsDWARFExpression() const { return m_type == isDWARFExpression; }
@@ -145,17 +140,9 @@ class UnwindPlan {
m_location.reg_num = reg_num;
}
- void SetIsRegisterPlusOffset(uint32_t reg_num, int32_t offset = 0) {
- m_type = isOtherRegisterPlusOffset;
- m_location.reg_plus_offset.reg_num = reg_num;
- m_location.reg_plus_offset.offset = offset;
- }
-
uint32_t GetRegisterNumber() const {
if (m_type == inOtherRegister)
return m_location.reg_num;
- if (m_type == isOtherRegisterPlusOffset)
- return m_location.reg_plus_offset.reg_num;
return LLDB_INVALID_REGNUM;
}
@@ -169,8 +156,6 @@ class UnwindPlan {
case atAFAPlusOffset:
case isAFAPlusOffset:
return m_location.offset;
- case inOtherRegister:
- return m_location.reg_plus_offset.offset;
default:
return 0;
}
@@ -219,11 +204,6 @@ class UnwindPlan {
} expr;
// For m_type == isConstant
uint64_t constant_value;
- // For m_type == inOtherRegisterPlusOffset
- struct {
- uint32_t reg_num;
- int32_t offset;
- } reg_plus_offset;
} m_location;
};
diff --git a/lldb/source/Symbol/UnwindPlan.cpp
b/lldb/source/Symbol/UnwindPlan.cpp
index 93587568a7e64..9245e52732061 100644
--- a/lldb/source/Symbol/UnwindPlan.cpp
+++ b/lldb/source/Symbol/UnwindPlan.cpp
@@ -42,12 +42,6 @@ bool UnwindPlan::Row::AbstractRegisterLocation::operator==(
case inOtherRegister:
return m_location.reg_num == rhs.m_location.reg_num;
- case isOtherRegisterPlusOffset:
- return m_location.reg_plus_offset.reg_num ==
- rhs.m_location.reg_plus_offset.reg_num &&
- m_location.reg_plus_offset.offset ==
- rhs.m_location.reg_plus_offset.offset;
-
case atDWARFExpression:
case isDWARFExpression:
if (m_location.expr.length == rhs.m_location.expr.length)
@@ -151,17 +145,6 @@ void UnwindPlan::Row::AbstractRegisterLocation::Dump(
s.Printf("=reg(%u)", m_location.reg_num);
} break;
- case isOtherRegisterPlusOffset: {
- const RegisterInfo *other_reg_info = nullptr;
- if (unwind_plan)
- other_reg_info = unwind_plan->GetRegisterInfo(thread,
m_location.reg_num);
- if (other_reg_info)
- s.Printf("=%s", other_reg_info->name);
- else
- s.Printf("=reg(%u)+%u", m_location.reg_plus_offset.reg_num,
- m_location.reg_plus_offset.offset);
- } break;
-
case atDWARFExpression:
case isDWARFExpression: {
s.PutChar('=');
diff --git a/lldb/source/Target/RegisterContextUnwind.cpp
b/lldb/source/Target/RegisterContextUnwind.cpp
index 80345e6d3588c..9e9e2d86958f3 100644
--- a/lldb/source/Target/RegisterContextUnwind.cpp
+++ b/lldb/source/Target/RegisterContextUnwind.cpp
@@ -1655,30 +1655,6 @@ RegisterContextUnwind::SavedLocationForRegister(
return UnwindLLDB::RegisterSearchResult::eRegisterFound;
}
- if (abs_regloc->IsOtherRegisterPlusOffset()) {
- uint32_t unwindplan_regnum = abs_regloc->GetRegisterNumber();
- int unwindplan_offset = abs_regloc->GetOffset();
- RegisterNumber row_regnum(m_thread, abs_regkind, unwindplan_regnum);
- if (row_regnum.GetAsKind(eRegisterKindLLDB) == LLDB_INVALID_REGNUM) {
- UnwindLogMsg("could not supply caller's %s (%d) location - was saved in "
- "another reg+offset but couldn't convert that regnum",
- regnum.GetName(), regnum.GetAsKind(eRegisterKindLLDB));
- return UnwindLLDB::RegisterSearchResult::eRegisterNotFound;
- }
- regloc.type =
- UnwindLLDB::ConcreteRegisterLocation::eRegisterIsRegisterPlusOffset;
- regloc.location.reg_plus_offset.register_number =
- row_regnum.GetAsKind(eRegisterKindLLDB);
- regloc.location.reg_plus_offset.offset = unwindplan_offset;
- m_registers[regnum.GetAsKind(eRegisterKindLLDB)] = regloc;
- UnwindLogMsg("supplying caller's register %s (%d), "
- "from register %s (%d) plus offset %u",
- regnum.GetName(), regnum.GetAsKind(eRegisterKindLLDB),
- row_regnum.GetName(), row_regnum.GetAsKind(eRegisterKindLLDB),
- unwindplan_offset);
- return UnwindLLDB::RegisterSearchResult::eRegisterFound;
- }
-
if (abs_regloc->IsDWARFExpression() || abs_regloc->IsAtDWARFExpression()) {
DataExtractor dwarfdata(abs_regloc->GetDWARFExpressionBytes(),
abs_regloc->GetDWARFExpressionLength(),
>From 321b51671a9a2d492cc40d5d146f6a4e13776886 Mon Sep 17 00:00:00 2001
From: Daniel Sanders <daniel_l_sand...@apple.com>
Date: Mon, 28 Jul 2025 12:58:48 -0700
Subject: [PATCH 4/6] fixup: formatting
---
lldb/include/lldb/Symbol/UnwindPlan.h | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff --git a/lldb/include/lldb/Symbol/UnwindPlan.h
b/lldb/include/lldb/Symbol/UnwindPlan.h
index a38d36a69302d..fe8081f83c590 100644
--- a/lldb/include/lldb/Symbol/UnwindPlan.h
+++ b/lldb/include/lldb/Symbol/UnwindPlan.h
@@ -57,19 +57,19 @@ class UnwindPlan {
class AbstractRegisterLocation {
public:
enum RestoreType {
- unspecified, // not specified, we may be able to assume this
- // is the same register. gcc doesn't specify all
- // initial values so we really don't know...
- undefined, // reg is not available, e.g. volatile reg
- same, // reg is unchanged
- atCFAPlusOffset, // reg = deref(CFA + offset)
- isCFAPlusOffset, // reg = CFA + offset
- atAFAPlusOffset, // reg = deref(AFA + offset)
- isAFAPlusOffset, // reg = AFA + offset
- inOtherRegister, // reg = other reg
- atDWARFExpression, // reg = deref(eval(dwarf_expr))
- isDWARFExpression, // reg = eval(dwarf_expr)
- isConstant // reg = constant
+ unspecified, // not specified, we may be able to assume this
+ // is the same register. gcc doesn't specify all
+ // initial values so we really don't know...
+ undefined, // reg is not available, e.g. volatile reg
+ same, // reg is unchanged
+ atCFAPlusOffset, // reg = deref(CFA + offset)
+ isCFAPlusOffset, // reg = CFA + offset
+ atAFAPlusOffset, // reg = deref(AFA + offset)
+ isAFAPlusOffset, // reg = AFA + offset
+ inOtherRegister, // reg = other reg
+ atDWARFExpression, // reg = deref(eval(dwarf_expr))
+ isDWARFExpression, // reg = eval(dwarf_expr)
+ isConstant // reg = constant
};
AbstractRegisterLocation() : m_location() {}
>From 2092e5660273141aa3abda9f297a1017d8d135f2 Mon Sep 17 00:00:00 2001
From: Daniel Sanders <daniel_l_sand...@apple.com>
Date: Wed, 30 Jul 2025 19:19:49 -0700
Subject: [PATCH 5/6] fixup: Additional test case
---
.../Inputs/eh-frame-dwarf-unwind-val-offset.s | 46 +++++++++++++++
.../eh-frame-dwarf-unwind-val-offset.test | 58 +++++++++++++++++++
2 files changed, 104 insertions(+)
create mode 100644
lldb/test/Shell/Unwind/Inputs/eh-frame-dwarf-unwind-val-offset.s
create mode 100644 lldb/test/Shell/Unwind/eh-frame-dwarf-unwind-val-offset.test
diff --git a/lldb/test/Shell/Unwind/Inputs/eh-frame-dwarf-unwind-val-offset.s
b/lldb/test/Shell/Unwind/Inputs/eh-frame-dwarf-unwind-val-offset.s
new file mode 100644
index 0000000000000..b0ce2c29c9991
--- /dev/null
+++ b/lldb/test/Shell/Unwind/Inputs/eh-frame-dwarf-unwind-val-offset.s
@@ -0,0 +1,46 @@
+ .text
+ .globl bar
+bar:
+ .cfi_startproc
+ leal (%edi, %edi), %eax
+ ret
+ .cfi_endproc
+
+ .globl foo
+foo:
+ .cfi_startproc
+ .cfi_escape 0x16, 0x10, 0x06, 0x38, 0x1c, 0x06, 0x08, 0x47, 0x1c
+ # Clobber r12 and record that it's reconstructable from CFA
+ .cfi_val_offset %r12, 0
+ movq $0x456, %r12
+ call bar
+ addl $1, %eax
+ # Reconstruct %r12
+ movq %rsp, %r12
+ addq %r12, 8
+ popq %rdi
+ subq $0x47, %rdi
+ jmp *%rdi # Return
+ .cfi_endproc
+
+ .globl asm_main
+asm_main:
+ .cfi_startproc
+ pushq %rbp
+ .cfi_def_cfa_offset 16
+ .cfi_offset %rbp, -16
+ movq %rsp, %rbp
+ movq %rsp, %r12
+ .cfi_def_cfa_register %rbp
+ movl $47, %edi
+
+ # Non-standard calling convention. The real return address must be
+ # decremented by 0x47.
+ leaq 0x47+1f(%rip), %rax
+ pushq %rax
+ jmp foo # call
+1:
+ popq %rbp
+ .cfi_def_cfa %rsp, 8
+ ret
+ .cfi_endproc
diff --git a/lldb/test/Shell/Unwind/eh-frame-dwarf-unwind-val-offset.test
b/lldb/test/Shell/Unwind/eh-frame-dwarf-unwind-val-offset.test
new file mode 100644
index 0000000000000..00b5fd31113b8
--- /dev/null
+++ b/lldb/test/Shell/Unwind/eh-frame-dwarf-unwind-val-offset.test
@@ -0,0 +1,58 @@
+# Test handing of the dwarf val_offset() rule which can be used to reconstruct
+# the value of a register that is neither in a live register or saved on the
+# stack but is computable with CFA + offset.
+
+# UNSUPPORTED: system-windows, ld_new-bug
+# REQUIRES: target-x86_64, native
+
+# RUN: %clang_host %p/Inputs/call-asm.c
%p/Inputs/eh-frame-dwarf-unwind-val-offset.s -o %t
+# RUN: %lldb %t -s %s -o exit | FileCheck %s
+
+breakpoint set -n asm_main
+# CHECK: Breakpoint 1: where = {{.*}}`asm_main
+
+breakpoint set -n bar
+# CHECK: Breakpoint 2: where = {{.*}}`bar
+
+process launch
+# CHECK: stop reason = breakpoint 1.1
+
+stepi
+stepi
+stepi
+print/x $r12
+# CHECK: (unsigned long) 0x[[#%.16x,R12:]]{{$}}
+
+continue
+# CHECK: stop reason = breakpoint 2.1
+
+thread backtrace
+# CHECK: frame #0: {{.*}}`bar
+# CHECK: frame #1: {{.*}}`foo + 12
+# CHECK: frame #2: {{.*}}`asm_main + 25
+
+target modules show-unwind -n bar
+# CHECK: eh_frame UnwindPlan:
+# CHECK: row[0]: 0: CFA=rsp +8 => rip=[CFA-8]
+
+target modules show-unwind -n foo
+# CHECK: eh_frame UnwindPlan:
+# CHECK: row[0]: 0: CFA=rsp +8 => r12=CFA+0 rip=DW_OP_lit8, DW_OP_minus,
DW_OP_deref, DW_OP_const1u 0x47, DW_OP_minus
+
+target modules show-unwind -n asm_main
+# CHECK: eh_frame UnwindPlan:
+# CHECK: row[0]: 0: CFA=rsp +8 => rip=[CFA-8]
+# CHECK: row[1]: 1: CFA=rsp+16 => rbp=[CFA-16] rip=[CFA-8]
+# CHECK: row[2]: 7: CFA=rbp+16 => rbp=[CFA-16] rip=[CFA-8]
+# CHECK: row[3]: 26: CFA=rsp +8 => rbp=[CFA-16] rip=[CFA-8]
+
+print/x $r12
+# CHECK: (unsigned long) 0x0000000000000456
+
+frame select 1
+print/x $r12
+# CHECK: (unsigned long) 0x0000000000000456
+
+frame select 2
+print/x $r12
+# CHECK: (unsigned long) 0x[[#R12]]
>From ed7dea3a7b9afcc11bdf4f6356f24205e1afaa81 Mon Sep 17 00:00:00 2001
From: Daniel Sanders <daniel_l_sand...@apple.com>
Date: Wed, 30 Jul 2025 19:31:24 -0700
Subject: [PATCH 6/6] fixup: Use a non-zero offset for the .cfi_val_offset
---
.../Unwind/Inputs/eh-frame-dwarf-unwind-val-offset.s | 3 ++-
.../Shell/Unwind/eh-frame-dwarf-unwind-val-offset.test | 10 +++++-----
2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/lldb/test/Shell/Unwind/Inputs/eh-frame-dwarf-unwind-val-offset.s
b/lldb/test/Shell/Unwind/Inputs/eh-frame-dwarf-unwind-val-offset.s
index b0ce2c29c9991..cd67114498bb8 100644
--- a/lldb/test/Shell/Unwind/Inputs/eh-frame-dwarf-unwind-val-offset.s
+++ b/lldb/test/Shell/Unwind/Inputs/eh-frame-dwarf-unwind-val-offset.s
@@ -11,7 +11,7 @@ foo:
.cfi_startproc
.cfi_escape 0x16, 0x10, 0x06, 0x38, 0x1c, 0x06, 0x08, 0x47, 0x1c
# Clobber r12 and record that it's reconstructable from CFA
- .cfi_val_offset %r12, 0
+ .cfi_val_offset %r12, 32
movq $0x456, %r12
call bar
addl $1, %eax
@@ -31,6 +31,7 @@ asm_main:
.cfi_offset %rbp, -16
movq %rsp, %rbp
movq %rsp, %r12
+ addq $32, %r12
.cfi_def_cfa_register %rbp
movl $47, %edi
diff --git a/lldb/test/Shell/Unwind/eh-frame-dwarf-unwind-val-offset.test
b/lldb/test/Shell/Unwind/eh-frame-dwarf-unwind-val-offset.test
index 00b5fd31113b8..64811e6196326 100644
--- a/lldb/test/Shell/Unwind/eh-frame-dwarf-unwind-val-offset.test
+++ b/lldb/test/Shell/Unwind/eh-frame-dwarf-unwind-val-offset.test
@@ -29,7 +29,7 @@ continue
thread backtrace
# CHECK: frame #0: {{.*}}`bar
# CHECK: frame #1: {{.*}}`foo + 12
-# CHECK: frame #2: {{.*}}`asm_main + 25
+# CHECK: frame #2: {{.*}}`asm_main + 29
target modules show-unwind -n bar
# CHECK: eh_frame UnwindPlan:
@@ -37,14 +37,14 @@ target modules show-unwind -n bar
target modules show-unwind -n foo
# CHECK: eh_frame UnwindPlan:
-# CHECK: row[0]: 0: CFA=rsp +8 => r12=CFA+0 rip=DW_OP_lit8, DW_OP_minus,
DW_OP_deref, DW_OP_const1u 0x47, DW_OP_minus
+# CHECK: row[0]: 0: CFA=rsp +8 => r12=CFA+32 rip=DW_OP_lit8, DW_OP_minus,
DW_OP_deref, DW_OP_const1u 0x47, DW_OP_minus
target modules show-unwind -n asm_main
# CHECK: eh_frame UnwindPlan:
# CHECK: row[0]: 0: CFA=rsp +8 => rip=[CFA-8]
# CHECK: row[1]: 1: CFA=rsp+16 => rbp=[CFA-16] rip=[CFA-8]
-# CHECK: row[2]: 7: CFA=rbp+16 => rbp=[CFA-16] rip=[CFA-8]
-# CHECK: row[3]: 26: CFA=rsp +8 => rbp=[CFA-16] rip=[CFA-8]
+# CHECK: row[2]: 11: CFA=rbp+16 => rbp=[CFA-16] rip=[CFA-8]
+# CHECK: row[3]: 30: CFA=rsp +8 => rbp=[CFA-16] rip=[CFA-8]
print/x $r12
# CHECK: (unsigned long) 0x0000000000000456
@@ -55,4 +55,4 @@ print/x $r12
frame select 2
print/x $r12
-# CHECK: (unsigned long) 0x[[#R12]]
+# CHECK: (unsigned long) 0x[[#R12 + 32]]
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