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[lldb] Fix offset computation in RegisterContextUnwind #137155

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Merged
merged 1 commit into from
May 15, 2025
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[lldb] Fix offset computation in RegisterContextUnwind #137155

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13 changes: 3 additions & 10 deletions lldb/include/lldb/Core/Address.h
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Original file line number Diff line number Diff line change
Expand Up @@ -371,22 +371,15 @@ class Address {
bool ResolveAddressUsingFileSections(lldb::addr_t addr,
const SectionList *sections);

/// Resolve this address to its containing function and optionally get
/// that function's address range.
/// Resolve this address to its containing function.
///
/// \param[out] sym_ctx
/// The symbol context describing the function in which this address lies
///
/// \parm[out] addr_range_ptr
/// Pointer to the AddressRange to fill in with the function's address
/// range. Caller may pass null if they don't need the address range.
///
/// \return
/// Returns \b false if the function/symbol could not be resolved
/// or if the address range was requested and could not be resolved;
/// Returns \b false if the function/symbol could not be resolved;
/// returns \b true otherwise.
bool ResolveFunctionScope(lldb_private::SymbolContext &sym_ctx,
lldb_private::AddressRange *addr_range_ptr = nullptr);
bool ResolveFunctionScope(lldb_private::SymbolContext &sym_ctx);

/// Set the address to represent \a load_addr.
///
Expand Down
15 changes: 2 additions & 13 deletions lldb/source/Core/Address.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -263,22 +263,11 @@ bool Address::ResolveAddressUsingFileSections(addr_t file_addr,
return false; // Failed to resolve this address to a section offset value
}

/// if "addr_range_ptr" is not NULL, then fill in with the address range of the function.
bool Address::ResolveFunctionScope(SymbolContext &sym_ctx,
AddressRange *addr_range_ptr) {
bool Address::ResolveFunctionScope(SymbolContext &sym_ctx) {
constexpr SymbolContextItem resolve_scope =
eSymbolContextFunction | eSymbolContextSymbol;

if (!(CalculateSymbolContext(&sym_ctx, resolve_scope) & resolve_scope)) {
if (addr_range_ptr)
addr_range_ptr->Clear();
return false;
}

if (!addr_range_ptr)
return true;

return sym_ctx.GetAddressRange(resolve_scope, 0, false, *addr_range_ptr);
return CalculateSymbolContext(&sym_ctx, resolve_scope) & resolve_scope;
}

ModuleSP Address::GetModule() const {
Expand Down
40 changes: 16 additions & 24 deletions lldb/source/Target/RegisterContextUnwind.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -160,8 +160,7 @@ void RegisterContextUnwind::InitializeZerothFrame() {
UnwindLogMsg("using architectural default unwind method");
}

AddressRange addr_range;
m_sym_ctx_valid = m_current_pc.ResolveFunctionScope(m_sym_ctx, &addr_range);
m_sym_ctx_valid = m_current_pc.ResolveFunctionScope(m_sym_ctx);

if (m_sym_ctx.symbol) {
UnwindLogMsg("with pc value of 0x%" PRIx64 ", symbol name is '%s'",
Expand All @@ -185,15 +184,9 @@ void RegisterContextUnwind::InitializeZerothFrame() {
// If we were able to find a symbol/function, set addr_range to the bounds of
// that symbol/function. else treat the current pc value as the start_pc and
// record no offset.
if (addr_range.GetBaseAddress().IsValid()) {
m_start_pc = addr_range.GetBaseAddress();
if (m_current_pc.GetSection() == m_start_pc.GetSection()) {
m_current_offset = m_current_pc.GetOffset() - m_start_pc.GetOffset();
} else if (m_current_pc.GetModule() == m_start_pc.GetModule()) {
// This means that whatever symbol we kicked up isn't really correct ---
// we should not cross section boundaries ... We really should NULL out
// the function/symbol in this case unless there is a bad assumption here
// due to inlined functions?
if (m_sym_ctx_valid) {
m_start_pc = m_sym_ctx.GetFunctionOrSymbolAddress();
if (m_current_pc.GetModule() == m_start_pc.GetModule()) {
m_current_offset =
m_current_pc.GetFileAddress() - m_start_pc.GetFileAddress();
}
Expand Down Expand Up @@ -498,8 +491,7 @@ void RegisterContextUnwind::InitializeNonZerothFrame() {
return;
}

AddressRange addr_range;
m_sym_ctx_valid = m_current_pc.ResolveFunctionScope(m_sym_ctx, &addr_range);
m_sym_ctx_valid = m_current_pc.ResolveFunctionScope(m_sym_ctx);

if (m_sym_ctx.symbol) {
UnwindLogMsg("with pc value of 0x%" PRIx64 ", symbol name is '%s'", pc,
Expand All @@ -523,9 +515,8 @@ void RegisterContextUnwind::InitializeNonZerothFrame() {
// Don't decrement if we're "above" an asynchronous event like
// sigtramp.
decr_pc_and_recompute_addr_range = false;
} else if (!addr_range.GetBaseAddress().IsValid() ||
addr_range.GetBaseAddress().GetSection() != m_current_pc.GetSection() ||
addr_range.GetBaseAddress().GetOffset() != m_current_pc.GetOffset()) {
} else if (Address addr = m_sym_ctx.GetFunctionOrSymbolAddress();
addr != m_current_pc) {
// If our "current" pc isn't the start of a function, decrement the pc
// if we're up the stack.
if (m_behaves_like_zeroth_frame)
Expand Down Expand Up @@ -558,7 +549,7 @@ void RegisterContextUnwind::InitializeNonZerothFrame() {
Address temporary_pc;
temporary_pc.SetLoadAddress(pc - 1, &process->GetTarget());
m_sym_ctx.Clear(false);
m_sym_ctx_valid = temporary_pc.ResolveFunctionScope(m_sym_ctx, &addr_range);
m_sym_ctx_valid = temporary_pc.ResolveFunctionScope(m_sym_ctx);

UnwindLogMsg("Symbol is now %s",
GetSymbolOrFunctionName(m_sym_ctx).AsCString(""));
Expand All @@ -567,8 +558,8 @@ void RegisterContextUnwind::InitializeNonZerothFrame() {
// If we were able to find a symbol/function, set addr_range_ptr to the
// bounds of that symbol/function. else treat the current pc value as the
// start_pc and record no offset.
if (addr_range.GetBaseAddress().IsValid()) {
m_start_pc = addr_range.GetBaseAddress();
if (m_sym_ctx_valid) {
m_start_pc = m_sym_ctx.GetFunctionOrSymbolAddress();
m_current_offset = pc - m_start_pc.GetLoadAddress(&process->GetTarget());
m_current_offset_backed_up_one = m_current_offset;
if (decr_pc_and_recompute_addr_range &&
Expand Down Expand Up @@ -1939,8 +1930,7 @@ void RegisterContextUnwind::PropagateTrapHandlerFlagFromUnwindPlan(
GetSymbolOrFunctionName(m_sym_ctx).AsCString(""));
m_current_offset_backed_up_one = m_current_offset;

AddressRange addr_range;
m_sym_ctx_valid = m_current_pc.ResolveFunctionScope(m_sym_ctx, &addr_range);
m_sym_ctx_valid = m_current_pc.ResolveFunctionScope(m_sym_ctx);

UnwindLogMsg("Symbol is now %s",
GetSymbolOrFunctionName(m_sym_ctx).AsCString(""));
Expand All @@ -1949,9 +1939,11 @@ void RegisterContextUnwind::PropagateTrapHandlerFlagFromUnwindPlan(
Process *process = exe_ctx.GetProcessPtr();
Target *target = &process->GetTarget();

m_start_pc = addr_range.GetBaseAddress();
m_current_offset =
m_current_pc.GetLoadAddress(target) - m_start_pc.GetLoadAddress(target);
if (m_sym_ctx_valid) {
m_start_pc = m_sym_ctx.GetFunctionOrSymbolAddress();
m_current_offset = m_current_pc.GetLoadAddress(target) -
m_start_pc.GetLoadAddress(target);
}
}
}

Expand Down
59 changes: 31 additions & 28 deletions lldb/test/Shell/Unwind/Inputs/basic-block-sections-with-dwarf.s
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Original file line number Diff line number Diff line change
Expand Up @@ -19,19 +19,16 @@ baz:
.Lbaz_end:
.size baz, .Lbaz_end-baz

.type foo,@function
foo:
foo.__part.3:
.cfi_startproc
pushq %rbx
.cfi_def_cfa_offset 16
.cfi_def_cfa_offset 32
.cfi_offset %rbx, -16
movl %edi, %ebx
cmpl $0, %ebx
je foo.__part.2
jmp foo.__part.1
addq $24, %rsp
.cfi_def_cfa %rsp, 8
retq
.Lfoo.__part.3_end:
.size foo.__part.3, .Lfoo.__part.3_end-foo.__part.3
.cfi_endproc
.Lfoo_end:
.size foo, .Lfoo_end-foo

# NB: Deliberately inserting padding to separate the two parts of the function
# as we're currently only parsing a single FDE entry from a (coalesced) address
Expand All @@ -40,58 +37,64 @@ foo:

foo.__part.1:
.cfi_startproc
.cfi_def_cfa_offset 16
.cfi_def_cfa_offset 32
.cfi_offset %rbx, -16
subq $16, %rsp
.cfi_def_cfa_offset 32
.cfi_def_cfa_offset 48
callq bar
addq $16, %rsp
.cfi_def_cfa_offset 32
jmp foo.__part.3
.Lfoo.__part.1_end:
.size foo.__part.1, .Lfoo.__part.1_end-foo.__part.1
.cfi_endproc

bar:
.cfi_startproc
subq $24, %rsp
.cfi_def_cfa_offset 32
subq $88, %rsp
.cfi_def_cfa_offset 96
xorl %edi, %edi
callq foo
addq $24, %rsp
addq $88, %rsp
.cfi_def_cfa %rsp, 8
retq
.cfi_endproc
.Lbar_end:
.size bar, .Lbar_end-bar

foo.__part.2:
.type foo,@function
foo:
.cfi_startproc
pushq %rbx
.cfi_def_cfa_offset 16
.cfi_offset %rbx, -16
movl %edi, %ebx
cmpl $0, %ebx
je foo.__part.2
subq $16, %rsp
.cfi_def_cfa_offset 32
callq baz
jmp foo.__part.3
.Lfoo.__part.2_end:
.size foo.__part.2, .Lfoo.__part.2_end-foo.__part.2
jmp foo.__part.1
.cfi_endproc
.Lfoo_end:
.size foo, .Lfoo_end-foo

# NB: Deliberately inserting padding to separate the two parts of the function
# as we're currently only parsing a single FDE entry from a (coalesced) address
# range.
nop

foo.__part.3:
foo.__part.2:
.cfi_startproc
.cfi_def_cfa_offset 32
.cfi_def_cfa_offset 16
.cfi_offset %rbx, -16
addq $24, %rsp
.cfi_def_cfa %rsp, 8
retq
.Lfoo.__part.3_end:
.size foo.__part.3, .Lfoo.__part.3_end-foo.__part.3
subq $16, %rsp
.cfi_def_cfa_offset 32
callq baz
jmp foo.__part.3
.Lfoo.__part.2_end:
.size foo.__part.2, .Lfoo.__part.2_end-foo.__part.2
.cfi_endproc


.globl main
.type main,@function
main:
Expand Down
24 changes: 13 additions & 11 deletions lldb/test/Shell/Unwind/basic-block-sections-with-dwarf-static.test
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Original file line number Diff line number Diff line change
Expand Up @@ -22,15 +22,17 @@ image show-unwind --cached true -n foo
# CHECK-NEXT: This UnwindPlan is sourced from the compiler: yes.
# CHECK-NEXT: This UnwindPlan is valid at all instruction locations: no.
# CHECK-NEXT: This UnwindPlan is for a trap handler function: no.
# CHECK-NEXT: Address range of this UnwindPlan: [{{.*}}.text + 6-0x0000000000000010)[{{.*}}.text + 17-0x000000000000001c)[{{.*}}.text + 44-0x0000000000000037)[{{.*}}.text + 56-0x000000000000003d)
# CHECK-NEXT: row[0]: 0: CFA=rsp +8 => rip=[CFA-8]
# CHECK-NEXT: row[1]: 1: CFA=rsp+16 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[2]: 11: CFA=rsp+16 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[3]: 15: CFA=rsp+32 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[4]: 38: CFA=rsp+16 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[5]: 42: CFA=rsp+32 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[6]: 50: CFA=rsp+32 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[7]: 54: CFA=rsp +8 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: Address range of this UnwindPlan: [{{.*}}.text + 6-0x000000000000000b)[{{.*}}.text + 12-0x000000000000001b)[{{.*}}.text + 43-0x0000000000000039)[{{.*}}.text + 58-0x0000000000000045)
# CHECK-NEXT: row[0]: -37: CFA=rsp+32 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[1]: -33: CFA=rsp +8 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[2]: -31: CFA=rsp+32 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[3]: -27: CFA=rsp+48 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[4]: -18: CFA=rsp+32 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[5]: 0: CFA=rsp +8 => rip=[CFA-8]
# CHECK-NEXT: row[6]: 1: CFA=rsp+16 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[7]: 12: CFA=rsp+32 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[8]: 15: CFA=rsp+16 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-NEXT: row[9]: 19: CFA=rsp+32 => rbx=[CFA-16] rip=[CFA-8]
# CHECK-EMPTY:

image show-unwind --cached true -n bar
Expand All @@ -41,8 +43,8 @@ image show-unwind --cached true -n bar
# CHECK-NEXT: This UnwindPlan is sourced from the compiler: yes.
# CHECK-NEXT: This UnwindPlan is valid at all instruction locations: no.
# CHECK-NEXT: This UnwindPlan is for a trap handler function: no.
# CHECK-NEXT: Address range of this UnwindPlan: [{{.*}}.text + 28-0x000000000000002c)
# CHECK-NEXT: Address range of this UnwindPlan: [{{.*}}.text + 27-0x000000000000002b)
# CHECK-NEXT: row[0]: 0: CFA=rsp +8 => rip=[CFA-8]
# CHECK-NEXT: row[1]: 4: CFA=rsp+32 => rip=[CFA-8]
# CHECK-NEXT: row[1]: 4: CFA=rsp+96 => rip=[CFA-8]
# CHECK-NEXT: row[2]: 15: CFA=rsp +8 => rip=[CFA-8]
# CHECK-EMPTY:
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