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[lldb] Implement (SB)Function::GetInstructions for discontinuous functions #122933

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Merged
merged 2 commits into from
Jan 15, 2025
Merged

[lldb] Implement (SB)Function::GetInstructions for discontinuous functions #122933

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dd5dba7
[lldb] Implement (SB)Function::GetInstructions for discontinuous func…
labath Jan 14, 2025
49a7bd2
deref optional
labath Jan 15, 2025
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11 changes: 9 additions & 2 deletions lldb/include/lldb/Core/Disassembler.h
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Original file line number Diff line number Diff line change
Expand Up @@ -428,7 +428,7 @@ class Disassembler : public std::enable_shared_from_this<Disassembler>,
static lldb::DisassemblerSP
DisassembleRange(const ArchSpec &arch, const char *plugin_name,
const char *flavor, const char *cpu, const char *features,
Target &target, const AddressRange &disasm_range,
Target &target, llvm::ArrayRef<AddressRange> disasm_ranges,
bool force_live_memory = false);

static lldb::DisassemblerSP
Expand Down Expand Up @@ -460,7 +460,11 @@ class Disassembler : public std::enable_shared_from_this<Disassembler>,

size_t ParseInstructions(Target &target, Address address, Limit limit,
Stream *error_strm_ptr,
bool force_live_memory = false);
bool force_live_memory = false) {
m_instruction_list.Clear();
return AppendInstructions(target, address, limit, error_strm_ptr,
force_live_memory);
}

virtual size_t DecodeInstructions(const Address &base_addr,
const DataExtractor &data,
Expand All @@ -480,6 +484,9 @@ class Disassembler : public std::enable_shared_from_this<Disassembler>,
const char *flavor) = 0;

protected:
size_t AppendInstructions(Target &target, Address address, Limit limit,
Stream *error_strm_ptr, bool force_live_memory);

// SourceLine and SourceLinesToDisplay structures are only used in the mixed
// source and assembly display methods internal to this class.

Expand Down
2 changes: 1 addition & 1 deletion lldb/source/API/SBFunction.cpp
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Expand Up @@ -127,7 +127,7 @@ SBInstructionList SBFunction::GetInstructions(SBTarget target,
sb_instructions.SetDisassembler(Disassembler::DisassembleRange(
module_sp->GetArchitecture(), nullptr, flavor,
target_sp->GetDisassemblyCPU(), target_sp->GetDisassemblyFeatures(),
*target_sp, m_opaque_ptr->GetAddressRange(), force_live_memory));
*target_sp, m_opaque_ptr->GetAddressRanges(), force_live_memory));
}
}
return sb_instructions;
Expand Down
8 changes: 8 additions & 0 deletions lldb/source/API/SBInstructionList.cpp
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Expand Up @@ -151,6 +151,10 @@ bool SBInstructionList::GetDescription(Stream &sref) {
FormatEntity::Parse("${addr}: ", format);
SymbolContext sc;
SymbolContext prev_sc;

// Expected address of the next instruction. Used to print an empty line
// for non-contiguous blocks of insns.
std::optional<Address> next_addr;
for (size_t i = 0; i < num_instructions; ++i) {
Instruction *inst =
m_opaque_sp->GetInstructionList().GetInstructionAtIndex(i).get();
Expand All @@ -165,10 +169,14 @@ bool SBInstructionList::GetDescription(Stream &sref) {
addr, eSymbolContextEverything, sc);
}

if (next_addr && addr != next_addr)
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I'm not the most experienced with optionals, doesn't the second next_addr need to be *next_addr?

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It doesn't need to be because std::optional<T> defines an operator== for comparison with plain Ts (which treats an empty optional as different from all values of T), but yes, it would be better to compare the T directly since that's not the behavior I want (I basically want to treat the empty optional as equal to any address).

sref.EOL();
inst->Dump(&sref, max_opcode_byte_size, true, false,
/*show_control_flow_kind=*/false, nullptr, &sc, &prev_sc,
&format, 0);
sref.EOL();
next_addr = addr;
next_addr->Slide(inst->GetOpcode().GetByteSize());
}
return true;
}
Expand Down
27 changes: 11 additions & 16 deletions lldb/source/Core/Disassembler.cpp
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Expand Up @@ -123,22 +123,19 @@ static Address ResolveAddress(Target &target, const Address &addr) {
lldb::DisassemblerSP Disassembler::DisassembleRange(
const ArchSpec &arch, const char *plugin_name, const char *flavor,
const char *cpu, const char *features, Target &target,
const AddressRange &range, bool force_live_memory) {
if (range.GetByteSize() <= 0)
return {};

if (!range.GetBaseAddress().IsValid())
return {};

llvm::ArrayRef<AddressRange> disasm_ranges, bool force_live_memory) {
lldb::DisassemblerSP disasm_sp = Disassembler::FindPluginForTarget(
target, arch, flavor, cpu, features, plugin_name);

if (!disasm_sp)
return {};

const size_t bytes_disassembled = disasm_sp->ParseInstructions(
target, range.GetBaseAddress(), {Limit::Bytes, range.GetByteSize()},
nullptr, force_live_memory);
size_t bytes_disassembled = 0;
for (const AddressRange &range : disasm_ranges) {
bytes_disassembled += disasm_sp->AppendInstructions(
target, range.GetBaseAddress(), {Limit::Bytes, range.GetByteSize()},
nullptr, force_live_memory);
}
if (bytes_disassembled == 0)
return {};

Expand Down Expand Up @@ -1092,11 +1089,9 @@ InstructionList::GetIndexOfInstructionAtLoadAddress(lldb::addr_t load_addr,
return GetIndexOfInstructionAtAddress(address);
}

size_t Disassembler::ParseInstructions(Target &target, Address start,
Limit limit, Stream *error_strm_ptr,
bool force_live_memory) {
m_instruction_list.Clear();

size_t Disassembler::AppendInstructions(Target &target, Address start,
Limit limit, Stream *error_strm_ptr,
bool force_live_memory) {
if (!start.IsValid())
return 0;

Expand Down Expand Up @@ -1129,7 +1124,7 @@ size_t Disassembler::ParseInstructions(Target &target, Address start,
return DecodeInstructions(start, data, 0,
limit.kind == Limit::Instructions ? limit.value
: UINT32_MAX,
false, data_from_file);
/*append=*/true, data_from_file);
}

// Disassembler copy constructor
Expand Down
2 changes: 1 addition & 1 deletion lldb/source/Symbol/Function.cpp
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Expand Up @@ -488,7 +488,7 @@ lldb::DisassemblerSP Function::GetInstructions(const ExecutionContext &exe_ctx,
if (module_sp && exe_ctx.HasTargetScope()) {
return Disassembler::DisassembleRange(
module_sp->GetArchitecture(), nullptr, nullptr, nullptr, flavor,
exe_ctx.GetTargetRef(), GetAddressRange(), !prefer_file_cache);
exe_ctx.GetTargetRef(), GetAddressRanges(), !prefer_file_cache);
}
return lldb::DisassemblerSP();
}
Expand Down
11 changes: 11 additions & 0 deletions lldb/test/Shell/ScriptInterpreter/Python/sb_function_ranges.s
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Expand Up @@ -6,6 +6,16 @@

# CHECK: Found 1 function(s).
# CHECK: foo: [input.o[0x0-0xe), input.o[0x14-0x1c)]
# CHECK-NEXT: input.o[0x0]: cmpl $0x0, %edi
# CHECK-NEXT: input.o[0x3]: je 0x14
# CHECK-NEXT: input.o[0x5]: jmp 0x7
# CHECK-NEXT: input.o[0x7]: callq 0xe
# CHECK-NEXT: input.o[0xc]: jmp 0x1b
# CHECK-EMPTY:
# CHECK-NEXT: input.o[0x14]: callq 0x19
# CHECK-NEXT: input.o[0x19]: jmp 0x1b
# CHECK-NEXT: input.o[0x1b]: retq


#--- script.py
import lldb
Expand All @@ -17,6 +27,7 @@ def __lldb_init_module(debugger, internal_dict):
for ctx in sym_ctxs:
fn = ctx.function
print(f"{fn.name}: {fn.GetRanges()}")
print(fn.GetInstructions(target))

#--- input.s
# An example of a function which has been split into two parts. Roughly
Expand Down
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