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llvm/lldb/source/Expression/IRExecutionUnit.cpp
Michael Buch 332b4deb0d [lldb][IRExecutionUnit] Return error on failure to resolve function address (#161363) 
Starting with https://github.com/llvm/llvm-project/pull/148877 we
started encoding the module ID of the function DIE we are currently
parsing into its `AsmLabel` in the AST. When the JIT asks LLDB to
resolve our special mangled name, we would locate the module and resolve
the function/symbol we found in it.

If we are debugging with a `SymbolFileDWARFDebugMap`, the module ID we
encode is that of the `.o` file that is tracked by the debug-map. To
resolve the address of the DIE in that `.o` file, we have to ask
`SymbolFileDWARFDebugMap::LinkOSOAddress` to turn the address of the
`.o` DIE into a real address in the linked executable. This will only
work if the `.o` address was actually tracked by the debug-map. However,
if the function definition appears in multiple `.o` files (which is the
case for functions defined in headers), the linker will most likely
de-deuplicate that definition. So most `.o`'s definition DIEs for that
function won't have a contribution in the debug-map, and thus we fail to
resolve the address.

When debugging Clang on Darwin, e.g., you'd see:
```
(lldb) expr CXXDecl->getName()

error: Couldn't look up symbols:
  $__lldb_func::0x1:0x4000d000002359da:_ZNK5clang9NamedDecl7getNameEv
Hint: The expression tried to call a function that is not present in the target, perhaps because it was optimized out by the compiler.
```
unless you were stopped in the `.o` file whose definition of `getName`
made it into the final executable.

The fix here is to error out if we fail to resolve the address, causing
us to fall back on the old flow which did a lookup by mangled name,
which the `SymbolFileDWARFDebugMap` will handle correctly.

An alternative fix to this would be to encode the
`SymbolFileDWARFDebugMap`'s module-id. And implement
`SymbolFileDWARFDebugMap::ResolveFunctionCallLabel` by doing a mangled
name lookup. The proposed approach doesn't stop us from implementing
that, so we could choose to do it in a follow-up.

rdar://161393045
2025-10-01 08:37:15 +01:00

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//===-- IRExecutionUnit.cpp -----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/ExecutionEngine/ObjectCache.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DiagnosticHandler.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/raw_ostream.h"
#include "lldb/Core/Debugger.h"
#include "lldb/Core/Disassembler.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/Section.h"
#include "lldb/Expression/Expression.h"
#include "lldb/Expression/IRExecutionUnit.h"
#include "lldb/Expression/ObjectFileJIT.h"
#include "lldb/Host/HostInfo.h"
#include "lldb/Symbol/CompileUnit.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Symbol/SymbolFile.h"
#include "lldb/Symbol/SymbolVendor.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Language.h"
#include "lldb/Target/LanguageRuntime.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/DataBufferHeap.h"
#include "lldb/Utility/DataExtractor.h"
#include "lldb/Utility/LLDBAssert.h"
#include "lldb/Utility/LLDBLog.h"
#include "lldb/Utility/Log.h"
#include "lldb/lldb-defines.h"
#include <optional>
using namespace lldb_private;
IRExecutionUnit::IRExecutionUnit(std::unique_ptr<llvm::LLVMContext> &context_up,
std::unique_ptr<llvm::Module> &module_up,
ConstString &name,
const lldb::TargetSP &target_sp,
const SymbolContext &sym_ctx,
std::vector<std::string> &cpu_features)
: IRMemoryMap(target_sp), m_context_up(context_up.release()),
m_module_up(module_up.release()), m_module(m_module_up.get()),
m_cpu_features(cpu_features), m_name(name), m_sym_ctx(sym_ctx),
m_did_jit(false), m_function_load_addr(LLDB_INVALID_ADDRESS),
m_function_end_load_addr(LLDB_INVALID_ADDRESS),
m_reported_allocations(false), m_preferred_modules() {}
lldb::addr_t IRExecutionUnit::WriteNow(const uint8_t *bytes, size_t size,
Status &error) {
const bool zero_memory = false;
auto address_or_error =
Malloc(size, 8, lldb::ePermissionsWritable | lldb::ePermissionsReadable,
eAllocationPolicyMirror, zero_memory);
if (!address_or_error) {
error = Status::FromError(address_or_error.takeError());
return LLDB_INVALID_ADDRESS;
}
lldb::addr_t allocation_process_addr = *address_or_error;
WriteMemory(allocation_process_addr, bytes, size, error);
if (!error.Success()) {
Status err;
Free(allocation_process_addr, err);
return LLDB_INVALID_ADDRESS;
}
if (Log *log = GetLog(LLDBLog::Expressions)) {
DataBufferHeap my_buffer(size, 0);
Status err;
ReadMemory(my_buffer.GetBytes(), allocation_process_addr, size, err);
if (err.Success()) {
DataExtractor my_extractor(my_buffer.GetBytes(), my_buffer.GetByteSize(),
lldb::eByteOrderBig, 8);
my_extractor.PutToLog(log, 0, my_buffer.GetByteSize(),
allocation_process_addr, 16,
DataExtractor::TypeUInt8);
}
}
return allocation_process_addr;
}
void IRExecutionUnit::FreeNow(lldb::addr_t allocation) {
if (allocation == LLDB_INVALID_ADDRESS)
return;
Status err;
Free(allocation, err);
}
Status IRExecutionUnit::DisassembleFunction(Stream &stream,
lldb::ProcessSP &process_wp) {
Log *log = GetLog(LLDBLog::Expressions);
ExecutionContext exe_ctx(process_wp);
Status ret;
ret.Clear();
lldb::addr_t func_local_addr = LLDB_INVALID_ADDRESS;
lldb::addr_t func_remote_addr = LLDB_INVALID_ADDRESS;
for (JittedFunction &function : m_jitted_functions) {
if (function.m_name == m_name) {
func_local_addr = function.m_local_addr;
func_remote_addr = function.m_remote_addr;
}
}
if (func_local_addr == LLDB_INVALID_ADDRESS) {
ret = Status::FromErrorStringWithFormat(
"Couldn't find function %s for disassembly", m_name.AsCString());
return ret;
}
LLDB_LOGF(log,
"Found function, has local address 0x%" PRIx64
" and remote address 0x%" PRIx64,
(uint64_t)func_local_addr, (uint64_t)func_remote_addr);
std::pair<lldb::addr_t, lldb::addr_t> func_range;
func_range = GetRemoteRangeForLocal(func_local_addr);
if (func_range.first == 0 && func_range.second == 0) {
ret = Status::FromErrorStringWithFormat(
"Couldn't find code range for function %s", m_name.AsCString());
return ret;
}
LLDB_LOGF(log, "Function's code range is [0x%" PRIx64 "+0x%" PRIx64 "]",
func_range.first, func_range.second);
Target *target = exe_ctx.GetTargetPtr();
if (!target) {
ret = Status::FromErrorString("Couldn't find the target");
return ret;
}
lldb::WritableDataBufferSP buffer_sp(
new DataBufferHeap(func_range.second, 0));
Process *process = exe_ctx.GetProcessPtr();
Status err;
process->ReadMemory(func_remote_addr, buffer_sp->GetBytes(),
buffer_sp->GetByteSize(), err);
if (!err.Success()) {
ret = Status::FromErrorStringWithFormat("Couldn't read from process: %s",
err.AsCString("unknown error"));
return ret;
}
ArchSpec arch(target->GetArchitecture());
const char *plugin_name = nullptr;
const char *flavor_string = nullptr;
const char *cpu_string = nullptr;
const char *features_string = nullptr;
lldb::DisassemblerSP disassembler_sp = Disassembler::FindPlugin(
arch, flavor_string, cpu_string, features_string, plugin_name);
if (!disassembler_sp) {
ret = Status::FromErrorStringWithFormat(
"Unable to find disassembler plug-in for %s architecture.",
arch.GetArchitectureName());
return ret;
}
if (!process) {
ret = Status::FromErrorString("Couldn't find the process");
return ret;
}
DataExtractor extractor(buffer_sp, process->GetByteOrder(),
target->GetArchitecture().GetAddressByteSize());
if (log) {
LLDB_LOGF(log, "Function data has contents:");
extractor.PutToLog(log, 0, extractor.GetByteSize(), func_remote_addr, 16,
DataExtractor::TypeUInt8);
}
disassembler_sp->DecodeInstructions(Address(func_remote_addr), extractor, 0,
UINT32_MAX, false, false);
InstructionList &instruction_list = disassembler_sp->GetInstructionList();
instruction_list.Dump(&stream, true, true, /*show_control_flow_kind=*/false,
&exe_ctx);
return ret;
}
namespace {
struct IRExecDiagnosticHandler : public llvm::DiagnosticHandler {
Status *err;
IRExecDiagnosticHandler(Status *err) : err(err) {}
bool handleDiagnostics(const llvm::DiagnosticInfo &DI) override {
if (DI.getSeverity() == llvm::DS_Error) {
const auto &DISM = llvm::cast<llvm::DiagnosticInfoSrcMgr>(DI);
if (err && err->Success()) {
*err = Status::FromErrorStringWithFormat(
"IRExecution error: %s",
DISM.getSMDiag().getMessage().str().c_str());
}
}
return true;
}
};
} // namespace
void IRExecutionUnit::ReportSymbolLookupError(ConstString name) {
m_failed_lookups.push_back(name);
}
void IRExecutionUnit::GetRunnableInfo(Status &error, lldb::addr_t &func_addr,
lldb::addr_t &func_end) {
lldb::ProcessSP process_sp(GetProcessWP().lock());
static std::recursive_mutex s_runnable_info_mutex;
func_addr = LLDB_INVALID_ADDRESS;
func_end = LLDB_INVALID_ADDRESS;
if (!process_sp) {
error =
Status::FromErrorString("Couldn't write the JIT compiled code into the "
"process because the process is invalid");
return;
}
if (m_did_jit) {
func_addr = m_function_load_addr;
func_end = m_function_end_load_addr;
return;
};
std::lock_guard<std::recursive_mutex> guard(s_runnable_info_mutex);
m_did_jit = true;
Log *log = GetLog(LLDBLog::Expressions);
std::string error_string;
if (log) {
std::string s;
llvm::raw_string_ostream oss(s);
m_module->print(oss, nullptr);
LLDB_LOGF(log, "Module being sent to JIT: \n%s", s.c_str());
}
m_module_up->getContext().setDiagnosticHandler(
std::make_unique<IRExecDiagnosticHandler>(&error));
llvm::EngineBuilder builder(std::move(m_module_up));
llvm::Triple triple(m_module->getTargetTriple());
builder.setEngineKind(llvm::EngineKind::JIT)
.setErrorStr(&error_string)
.setRelocationModel(triple.isOSBinFormatMachO() ? llvm::Reloc::PIC_
: llvm::Reloc::Static)
.setMCJITMemoryManager(std::make_unique<MemoryManager>(*this))
.setOptLevel(llvm::CodeGenOptLevel::Less);
// Resulted jitted code can be placed too far from the code in the binary
// and thus can contain more than +-2GB jumps, that are not available
// in RISC-V without large code model.
if (triple.isRISCV64())
builder.setCodeModel(llvm::CodeModel::Large);
llvm::StringRef mArch;
llvm::StringRef mCPU;
llvm::SmallVector<std::string, 0> mAttrs;
for (std::string &feature : m_cpu_features)
mAttrs.push_back(feature);
llvm::TargetMachine *target_machine =
builder.selectTarget(triple, mArch, mCPU, mAttrs);
m_execution_engine_up.reset(builder.create(target_machine));
if (!m_execution_engine_up) {
error = Status::FromErrorStringWithFormat("Couldn't JIT the function: %s",
error_string.c_str());
return;
}
m_strip_underscore =
(m_execution_engine_up->getDataLayout().getGlobalPrefix() == '_');
class ObjectDumper : public llvm::ObjectCache {
public:
ObjectDumper(FileSpec output_dir) : m_out_dir(output_dir) {}
void notifyObjectCompiled(const llvm::Module *module,
llvm::MemoryBufferRef object) override {
int fd = 0;
llvm::SmallVector<char, 256> result_path;
std::string object_name_model =
"jit-object-" + module->getModuleIdentifier() + "-%%%.o";
FileSpec model_spec
= m_out_dir.CopyByAppendingPathComponent(object_name_model);
std::string model_path = model_spec.GetPath();
std::error_code result
= llvm::sys::fs::createUniqueFile(model_path, fd, result_path);
if (!result) {
llvm::raw_fd_ostream fds(fd, true);
fds.write(object.getBufferStart(), object.getBufferSize());
}
}
std::unique_ptr<llvm::MemoryBuffer>
getObject(const llvm::Module *module) override {
// Return nothing - we're just abusing the object-cache mechanism to dump
// objects.
return nullptr;
}
private:
FileSpec m_out_dir;
};
FileSpec save_objects_dir = process_sp->GetTarget().GetSaveJITObjectsDir();
if (save_objects_dir) {
m_object_cache_up = std::make_unique<ObjectDumper>(save_objects_dir);
m_execution_engine_up->setObjectCache(m_object_cache_up.get());
}
// Make sure we see all sections, including ones that don't have
// relocations...
m_execution_engine_up->setProcessAllSections(true);
m_execution_engine_up->DisableLazyCompilation();
for (llvm::Function &function : *m_module) {
if (function.isDeclaration() || function.hasPrivateLinkage())
continue;
const bool external = !function.hasLocalLinkage();
void *fun_ptr = m_execution_engine_up->getPointerToFunction(&function);
if (!error.Success()) {
// We got an error through our callback!
return;
}
if (!fun_ptr) {
error = Status::FromErrorStringWithFormat(
"'%s' was in the JITted module but wasn't lowered",
function.getName().str().c_str());
return;
}
m_jitted_functions.push_back(JittedFunction(
function.getName().str().c_str(), external, reinterpret_cast<uintptr_t>(fun_ptr)));
}
CommitAllocations(process_sp);
ReportAllocations(*m_execution_engine_up);
// We have to do this after calling ReportAllocations because for the MCJIT,
// getGlobalValueAddress will cause the JIT to perform all relocations. That
// can only be done once, and has to happen after we do the remapping from
// local -> remote. That means we don't know the local address of the
// Variables, but we don't need that for anything, so that's okay.
std::function<void(llvm::GlobalValue &)> RegisterOneValue = [this](
llvm::GlobalValue &val) {
if (val.hasExternalLinkage() && !val.isDeclaration()) {
uint64_t var_ptr_addr =
m_execution_engine_up->getGlobalValueAddress(val.getName().str());
lldb::addr_t remote_addr = GetRemoteAddressForLocal(var_ptr_addr);
// This is a really unfortunae API that sometimes returns local addresses
// and sometimes returns remote addresses, based on whether the variable
// was relocated during ReportAllocations or not.
if (remote_addr == LLDB_INVALID_ADDRESS) {
remote_addr = var_ptr_addr;
}
if (var_ptr_addr != 0)
m_jitted_global_variables.push_back(JittedGlobalVariable(
val.getName().str().c_str(), LLDB_INVALID_ADDRESS, remote_addr));
}
};
for (llvm::GlobalVariable &global_var : m_module->globals()) {
RegisterOneValue(global_var);
}
for (llvm::GlobalAlias &global_alias : m_module->aliases()) {
RegisterOneValue(global_alias);
}
WriteData(process_sp);
if (m_failed_lookups.size()) {
StreamString ss;
ss.PutCString("Couldn't look up symbols:\n");
bool emitNewLine = false;
for (ConstString failed_lookup : m_failed_lookups) {
if (emitNewLine)
ss.PutCString("\n");
emitNewLine = true;
ss.PutCString(" ");
ss.PutCString(Mangled(failed_lookup).GetDemangledName().GetStringRef());
}
m_failed_lookups.clear();
ss.PutCString(
"\nHint: The expression tried to call a function that is not present "
"in the target, perhaps because it was optimized out by the compiler.");
error = Status(ss.GetString().str());
return;
}
m_function_load_addr = LLDB_INVALID_ADDRESS;
m_function_end_load_addr = LLDB_INVALID_ADDRESS;
for (JittedFunction &jitted_function : m_jitted_functions) {
jitted_function.m_remote_addr =
GetRemoteAddressForLocal(jitted_function.m_local_addr);
if (!m_name.IsEmpty() && jitted_function.m_name == m_name) {
AddrRange func_range =
GetRemoteRangeForLocal(jitted_function.m_local_addr);
m_function_end_load_addr = func_range.first + func_range.second;
m_function_load_addr = jitted_function.m_remote_addr;
}
}
if (log) {
LLDB_LOGF(log, "Code can be run in the target.");
StreamString disassembly_stream;
Status err = DisassembleFunction(disassembly_stream, process_sp);
if (!err.Success()) {
LLDB_LOGF(log, "Couldn't disassemble function : %s",
err.AsCString("unknown error"));
} else {
LLDB_LOGF(log, "Function disassembly:\n%s", disassembly_stream.GetData());
}
LLDB_LOGF(log, "Sections: ");
for (AllocationRecord &record : m_records) {
if (record.m_process_address != LLDB_INVALID_ADDRESS) {
record.dump(log);
DataBufferHeap my_buffer(record.m_size, 0);
Status err;
ReadMemory(my_buffer.GetBytes(), record.m_process_address,
record.m_size, err);
if (err.Success()) {
DataExtractor my_extractor(my_buffer.GetBytes(),
my_buffer.GetByteSize(),
lldb::eByteOrderBig, 8);
my_extractor.PutToLog(log, 0, my_buffer.GetByteSize(),
record.m_process_address, 16,
DataExtractor::TypeUInt8);
}
} else {
record.dump(log);
DataExtractor my_extractor((const void *)record.m_host_address,
record.m_size, lldb::eByteOrderBig, 8);
my_extractor.PutToLog(log, 0, record.m_size, record.m_host_address, 16,
DataExtractor::TypeUInt8);
}
}
}
func_addr = m_function_load_addr;
func_end = m_function_end_load_addr;
}
IRExecutionUnit::~IRExecutionUnit() {
m_module_up.reset();
m_execution_engine_up.reset();
m_context_up.reset();
}
IRExecutionUnit::MemoryManager::MemoryManager(IRExecutionUnit &parent)
: m_default_mm_up(new llvm::SectionMemoryManager()), m_parent(parent) {}
IRExecutionUnit::MemoryManager::~MemoryManager() = default;
lldb::SectionType IRExecutionUnit::GetSectionTypeFromSectionName(
const llvm::StringRef &name, IRExecutionUnit::AllocationKind alloc_kind) {
lldb::SectionType sect_type = lldb::eSectionTypeCode;
switch (alloc_kind) {
case AllocationKind::Stub:
sect_type = lldb::eSectionTypeCode;
break;
case AllocationKind::Code:
sect_type = lldb::eSectionTypeCode;
break;
case AllocationKind::Data:
sect_type = lldb::eSectionTypeData;
break;
case AllocationKind::Global:
sect_type = lldb::eSectionTypeData;
break;
case AllocationKind::Bytes:
sect_type = lldb::eSectionTypeOther;
break;
}
if (!name.empty()) {
if (name == "__text" || name == ".text")
sect_type = lldb::eSectionTypeCode;
else if (name == "__data" || name == ".data")
sect_type = lldb::eSectionTypeCode;
else if (name.starts_with("__debug_") || name.starts_with(".debug_")) {
const uint32_t name_idx = name[0] == '_' ? 8 : 7;
llvm::StringRef dwarf_name(name.substr(name_idx));
sect_type = ObjectFile::GetDWARFSectionTypeFromName(dwarf_name);
} else if (name.starts_with("__apple_") || name.starts_with(".apple_"))
sect_type = lldb::eSectionTypeInvalid;
else if (name == "__objc_imageinfo")
sect_type = lldb::eSectionTypeOther;
}
return sect_type;
}
uint8_t *IRExecutionUnit::MemoryManager::allocateCodeSection(
uintptr_t Size, unsigned Alignment, unsigned SectionID,
llvm::StringRef SectionName) {
Log *log = GetLog(LLDBLog::Expressions);
uint8_t *return_value = m_default_mm_up->allocateCodeSection(
Size, Alignment, SectionID, SectionName);
m_parent.m_records.push_back(AllocationRecord(
(uintptr_t)return_value,
lldb::ePermissionsReadable | lldb::ePermissionsExecutable,
GetSectionTypeFromSectionName(SectionName, AllocationKind::Code), Size,
Alignment, SectionID, SectionName.str().c_str()));
LLDB_LOGF(log,
"IRExecutionUnit::allocateCodeSection(Size=0x%" PRIx64
", Alignment=%u, SectionID=%u) = %p",
(uint64_t)Size, Alignment, SectionID, (void *)return_value);
if (m_parent.m_reported_allocations) {
Status err;
lldb::ProcessSP process_sp =
m_parent.GetBestExecutionContextScope()->CalculateProcess();
m_parent.CommitOneAllocation(process_sp, err, m_parent.m_records.back());
}
return return_value;
}
uint8_t *IRExecutionUnit::MemoryManager::allocateDataSection(
uintptr_t Size, unsigned Alignment, unsigned SectionID,
llvm::StringRef SectionName, bool IsReadOnly) {
Log *log = GetLog(LLDBLog::Expressions);
uint8_t *return_value = m_default_mm_up->allocateDataSection(
Size, Alignment, SectionID, SectionName, IsReadOnly);
uint32_t permissions = lldb::ePermissionsReadable;
if (!IsReadOnly)
permissions |= lldb::ePermissionsWritable;
m_parent.m_records.push_back(AllocationRecord(
(uintptr_t)return_value, permissions,
GetSectionTypeFromSectionName(SectionName, AllocationKind::Data), Size,
Alignment, SectionID, SectionName.str().c_str()));
LLDB_LOGF(log,
"IRExecutionUnit::allocateDataSection(Size=0x%" PRIx64
", Alignment=%u, SectionID=%u) = %p",
(uint64_t)Size, Alignment, SectionID, (void *)return_value);
if (m_parent.m_reported_allocations) {
Status err;
lldb::ProcessSP process_sp =
m_parent.GetBestExecutionContextScope()->CalculateProcess();
m_parent.CommitOneAllocation(process_sp, err, m_parent.m_records.back());
}
return return_value;
}
void IRExecutionUnit::CollectCandidateCNames(std::vector<ConstString> &C_names,
ConstString name) {
if (m_strip_underscore && name.AsCString()[0] == '_')
C_names.insert(C_names.begin(), ConstString(&name.AsCString()[1]));
C_names.push_back(name);
}
void IRExecutionUnit::CollectCandidateCPlusPlusNames(
std::vector<ConstString> &CPP_names,
const std::vector<ConstString> &C_names, const SymbolContext &sc) {
if (auto *cpp_lang = Language::FindPlugin(lldb::eLanguageTypeC_plus_plus)) {
for (const ConstString &name : C_names) {
Mangled mangled(name);
if (cpp_lang->SymbolNameFitsToLanguage(mangled)) {
if (ConstString best_alternate =
cpp_lang->FindBestAlternateFunctionMangledName(mangled, sc)) {
CPP_names.push_back(best_alternate);
}
}
std::vector<ConstString> alternates =
cpp_lang->GenerateAlternateFunctionManglings(name);
CPP_names.insert(CPP_names.end(), alternates.begin(), alternates.end());
// As a last-ditch fallback, try the base name for C++ names. It's
// terrible, but the DWARF doesn't always encode "extern C" correctly.
ConstString basename =
cpp_lang->GetDemangledFunctionNameWithoutArguments(mangled);
CPP_names.push_back(basename);
}
}
}
class LoadAddressResolver {
public:
LoadAddressResolver(Target &target, bool &symbol_was_missing_weak)
: m_target(target), m_symbol_was_missing_weak(symbol_was_missing_weak) {}
std::optional<lldb::addr_t> Resolve(SymbolContextList &sc_list) {
if (sc_list.IsEmpty())
return std::nullopt;
lldb::addr_t load_address = LLDB_INVALID_ADDRESS;
// Missing_weak_symbol will be true only if we found only weak undefined
// references to this symbol.
m_symbol_was_missing_weak = true;
for (auto candidate_sc : sc_list.SymbolContexts()) {
// Only symbols can be weak undefined.
if (!candidate_sc.symbol ||
candidate_sc.symbol->GetType() != lldb::eSymbolTypeUndefined ||
!candidate_sc.symbol->IsWeak())
m_symbol_was_missing_weak = false;
// First try the symbol.
if (candidate_sc.symbol) {
load_address = candidate_sc.symbol->ResolveCallableAddress(m_target);
if (load_address == LLDB_INVALID_ADDRESS) {
Address addr = candidate_sc.symbol->GetAddress();
load_address = m_target.GetProcessSP()
? addr.GetLoadAddress(&m_target)
: addr.GetFileAddress();
}
}
// If that didn't work, try the function.
if (load_address == LLDB_INVALID_ADDRESS && candidate_sc.function) {
Address addr = candidate_sc.function->GetAddress();
load_address = m_target.GetProcessSP()
? addr.GetCallableLoadAddress(&m_target)
: addr.GetFileAddress();
}
// We found a load address.
if (load_address != LLDB_INVALID_ADDRESS) {
// If the load address is external, we're done.
const bool is_external =
(candidate_sc.function) ||
(candidate_sc.symbol && candidate_sc.symbol->IsExternal());
if (is_external)
return load_address;
// Otherwise, remember the best internal load address.
if (m_best_internal_load_address == LLDB_INVALID_ADDRESS)
m_best_internal_load_address = load_address;
}
}
// You test the address of a weak symbol against NULL to see if it is
// present. So we should return 0 for a missing weak symbol.
if (m_symbol_was_missing_weak)
return 0;
return std::nullopt;
}
lldb::addr_t GetBestInternalLoadAddress() const {
return m_best_internal_load_address;
}
private:
Target &m_target;
bool &m_symbol_was_missing_weak;
lldb::addr_t m_best_internal_load_address = LLDB_INVALID_ADDRESS;
};
/// Returns address of the function referred to by the special function call
/// label \c label.
static llvm::Expected<lldb::addr_t>
ResolveFunctionCallLabel(FunctionCallLabel &label,
const lldb_private::SymbolContext &sc,
bool &symbol_was_missing_weak) {
symbol_was_missing_weak = false;
if (!sc.target_sp)
return llvm::createStringError("target not available.");
auto module_sp = sc.target_sp->GetImages().FindModule(label.module_id);
if (!module_sp)
return llvm::createStringError(
llvm::formatv("failed to find module by UID {0}", label.module_id));
auto *symbol_file = module_sp->GetSymbolFile();
if (!symbol_file)
return llvm::createStringError(
llvm::formatv("no SymbolFile found on module {0:x}.", module_sp.get()));
auto sc_or_err = symbol_file->ResolveFunctionCallLabel(label);
if (!sc_or_err)
return llvm::joinErrors(
llvm::createStringError("failed to resolve function by UID:"),
sc_or_err.takeError());
SymbolContextList sc_list;
sc_list.Append(*sc_or_err);
LoadAddressResolver resolver(*sc.target_sp, symbol_was_missing_weak);
lldb::addr_t resolved_addr =
resolver.Resolve(sc_list).value_or(LLDB_INVALID_ADDRESS);
if (resolved_addr == LLDB_INVALID_ADDRESS)
return llvm::createStringError("couldn't resolve address for function");
return resolved_addr;
}
lldb::addr_t
IRExecutionUnit::FindInSymbols(const std::vector<ConstString> &names,
const lldb_private::SymbolContext &sc,
bool &symbol_was_missing_weak) {
symbol_was_missing_weak = false;
Target *target = sc.target_sp.get();
if (!target) {
// We shouldn't be doing any symbol lookup at all without a target.
return LLDB_INVALID_ADDRESS;
}
ModuleList non_local_images = target->GetImages();
// We'll process module_sp and any preferred modules separately, before the
// other modules.
non_local_images.Remove(sc.module_sp);
for (size_t i = 0; i < m_preferred_modules.GetSize(); ++i)
non_local_images.Remove(m_preferred_modules.GetModuleAtIndex(i));
LoadAddressResolver resolver(*target, symbol_was_missing_weak);
ModuleFunctionSearchOptions function_options;
function_options.include_symbols = true;
function_options.include_inlines = false;
for (const ConstString &name : names) {
// The lookup order here is as follows:
// 1) Functions in `sc.module_sp`
// 2) Functions in the preferred modules list
// 3) Functions in the other modules
// 4) Symbols in `sc.module_sp`
// 5) Symbols in the preferred modules list
// 6) Symbols in the other modules
if (sc.module_sp) {
SymbolContextList sc_list;
sc.module_sp->FindFunctions(name, CompilerDeclContext(),
lldb::eFunctionNameTypeFull, function_options,
sc_list);
if (auto load_addr = resolver.Resolve(sc_list))
return *load_addr;
}
{
SymbolContextList sc_list;
m_preferred_modules.FindFunctions(name, lldb::eFunctionNameTypeFull,
function_options, sc_list);
if (auto load_addr = resolver.Resolve(sc_list))
return *load_addr;
}
{
SymbolContextList sc_list;
non_local_images.FindFunctions(name, lldb::eFunctionNameTypeFull,
function_options, sc_list);
if (auto load_addr = resolver.Resolve(sc_list))
return *load_addr;
}
if (sc.module_sp) {
SymbolContextList sc_list;
sc.module_sp->FindSymbolsWithNameAndType(name, lldb::eSymbolTypeAny,
sc_list);
if (auto load_addr = resolver.Resolve(sc_list))
return *load_addr;
}
{
SymbolContextList sc_list;
m_preferred_modules.FindSymbolsWithNameAndType(name, lldb::eSymbolTypeAny,
sc_list);
if (auto load_addr = resolver.Resolve(sc_list))
return *load_addr;
}
{
SymbolContextList sc_list;
non_local_images.FindSymbolsWithNameAndType(name, lldb::eSymbolTypeAny,
sc_list);
if (auto load_addr = resolver.Resolve(sc_list))
return *load_addr;
}
lldb::addr_t best_internal_load_address =
resolver.GetBestInternalLoadAddress();
if (best_internal_load_address != LLDB_INVALID_ADDRESS)
return best_internal_load_address;
}
return LLDB_INVALID_ADDRESS;
}
lldb::addr_t
IRExecutionUnit::FindInRuntimes(const std::vector<ConstString> &names,
const lldb_private::SymbolContext &sc) {
lldb::TargetSP target_sp = sc.target_sp;
if (!target_sp) {
return LLDB_INVALID_ADDRESS;
}
lldb::ProcessSP process_sp = sc.target_sp->GetProcessSP();
if (!process_sp) {
return LLDB_INVALID_ADDRESS;
}
for (const ConstString &name : names) {
for (LanguageRuntime *runtime : process_sp->GetLanguageRuntimes()) {
lldb::addr_t symbol_load_addr = runtime->LookupRuntimeSymbol(name);
if (symbol_load_addr != LLDB_INVALID_ADDRESS)
return symbol_load_addr;
}
}
return LLDB_INVALID_ADDRESS;
}
lldb::addr_t IRExecutionUnit::FindInUserDefinedSymbols(
const std::vector<ConstString> &names,
const lldb_private::SymbolContext &sc) {
lldb::TargetSP target_sp = sc.target_sp;
for (const ConstString &name : names) {
lldb::addr_t symbol_load_addr = target_sp->GetPersistentSymbol(name);
if (symbol_load_addr != LLDB_INVALID_ADDRESS)
return symbol_load_addr;
}
return LLDB_INVALID_ADDRESS;
}
lldb::addr_t IRExecutionUnit::FindSymbol(lldb_private::ConstString name,
bool &missing_weak) {
if (name.GetStringRef().starts_with(FunctionCallLabelPrefix)) {
auto label_or_err = FunctionCallLabel::fromString(name);
if (!label_or_err) {
LLDB_LOG_ERROR(GetLog(LLDBLog::Expressions), label_or_err.takeError(),
"failed to create FunctionCallLabel from '{1}': {0}",
name.GetStringRef());
return LLDB_INVALID_ADDRESS;
}
if (auto addr_or_err =
ResolveFunctionCallLabel(*label_or_err, m_sym_ctx, missing_weak)) {
return *addr_or_err;
} else {
LLDB_LOG_ERROR(GetLog(LLDBLog::Expressions), addr_or_err.takeError(),
"Failed to resolve function call label '{1}': {0}",
name.GetStringRef());
// Fall back to lookup by name despite error in resolving the label.
// May happen in practice if the definition of a function lives in
// a different lldb_private::Module than it's declaration. Meaning
// we couldn't pin-point it using the information encoded in the label.
name.SetString(label_or_err->lookup_name);
}
}
// TODO: now with function call labels, do we still need to
// generate alternate manglings?
std::vector<ConstString> candidate_C_names;
std::vector<ConstString> candidate_CPlusPlus_names;
CollectCandidateCNames(candidate_C_names, name);
lldb::addr_t ret = FindInSymbols(candidate_C_names, m_sym_ctx, missing_weak);
if (ret != LLDB_INVALID_ADDRESS)
return ret;
// If we find the symbol in runtimes or user defined symbols it can't be
// a missing weak symbol.
missing_weak = false;
ret = FindInRuntimes(candidate_C_names, m_sym_ctx);
if (ret != LLDB_INVALID_ADDRESS)
return ret;
ret = FindInUserDefinedSymbols(candidate_C_names, m_sym_ctx);
if (ret != LLDB_INVALID_ADDRESS)
return ret;
CollectCandidateCPlusPlusNames(candidate_CPlusPlus_names, candidate_C_names,
m_sym_ctx);
ret = FindInSymbols(candidate_CPlusPlus_names, m_sym_ctx, missing_weak);
return ret;
}
void IRExecutionUnit::GetStaticInitializers(
std::vector<lldb::addr_t> &static_initializers) {
Log *log = GetLog(LLDBLog::Expressions);
llvm::GlobalVariable *global_ctors =
m_module->getNamedGlobal("llvm.global_ctors");
if (!global_ctors) {
LLDB_LOG(log, "Couldn't find llvm.global_ctors.");
return;
}
auto *ctor_array =
llvm::dyn_cast<llvm::ConstantArray>(global_ctors->getInitializer());
if (!ctor_array) {
LLDB_LOG(log, "llvm.global_ctors not a ConstantArray.");
return;
}
for (llvm::Use &ctor_use : ctor_array->operands()) {
auto *ctor_struct = llvm::dyn_cast<llvm::ConstantStruct>(ctor_use);
if (!ctor_struct)
continue;
// this is standardized
lldbassert(ctor_struct->getNumOperands() == 3);
auto *ctor_function =
llvm::dyn_cast<llvm::Function>(ctor_struct->getOperand(1));
if (!ctor_function) {
LLDB_LOG(log, "global_ctor doesn't contain an llvm::Function");
continue;
}
ConstString ctor_function_name(ctor_function->getName().str());
LLDB_LOG(log, "Looking for callable jitted function with name {0}.",
ctor_function_name);
for (JittedFunction &jitted_function : m_jitted_functions) {
if (ctor_function_name != jitted_function.m_name)
continue;
if (jitted_function.m_remote_addr == LLDB_INVALID_ADDRESS) {
LLDB_LOG(log, "Found jitted function with invalid address.");
continue;
}
static_initializers.push_back(jitted_function.m_remote_addr);
LLDB_LOG(log, "Calling function at address {0:x}.",
jitted_function.m_remote_addr);
break;
}
}
}
llvm::JITSymbol
IRExecutionUnit::MemoryManager::findSymbol(const std::string &Name) {
bool missing_weak = false;
uint64_t addr = GetSymbolAddressAndPresence(Name, missing_weak);
// This is a weak symbol:
if (missing_weak)
return llvm::JITSymbol(addr,
llvm::JITSymbolFlags::Exported | llvm::JITSymbolFlags::Weak);
else
return llvm::JITSymbol(addr, llvm::JITSymbolFlags::Exported);
}
uint64_t
IRExecutionUnit::MemoryManager::getSymbolAddress(const std::string &Name) {
bool missing_weak = false;
return GetSymbolAddressAndPresence(Name, missing_weak);
}
uint64_t
IRExecutionUnit::MemoryManager::GetSymbolAddressAndPresence(
const std::string &Name, bool &missing_weak) {
Log *log = GetLog(LLDBLog::Expressions);
ConstString name_cs(Name.c_str());
lldb::addr_t ret = m_parent.FindSymbol(name_cs, missing_weak);
if (ret == LLDB_INVALID_ADDRESS) {
LLDB_LOGF(log,
"IRExecutionUnit::getSymbolAddress(Name=\"%s\") = <not found>",
Name.c_str());
m_parent.ReportSymbolLookupError(name_cs);
return 0;
} else {
LLDB_LOGF(log, "IRExecutionUnit::getSymbolAddress(Name=\"%s\") = %" PRIx64,
Name.c_str(), ret);
return ret;
}
}
void *IRExecutionUnit::MemoryManager::getPointerToNamedFunction(
const std::string &Name, bool AbortOnFailure) {
return (void *)getSymbolAddress(Name);
}
lldb::addr_t
IRExecutionUnit::GetRemoteAddressForLocal(lldb::addr_t local_address) {
Log *log = GetLog(LLDBLog::Expressions);
for (AllocationRecord &record : m_records) {
if (local_address >= record.m_host_address &&
local_address < record.m_host_address + record.m_size) {
if (record.m_process_address == LLDB_INVALID_ADDRESS)
return LLDB_INVALID_ADDRESS;
lldb::addr_t ret =
record.m_process_address + (local_address - record.m_host_address);
LLDB_LOGF(log,
"IRExecutionUnit::GetRemoteAddressForLocal() found 0x%" PRIx64
" in [0x%" PRIx64 "..0x%" PRIx64 "], and returned 0x%" PRIx64
" from [0x%" PRIx64 "..0x%" PRIx64 "].",
local_address, (uint64_t)record.m_host_address,
(uint64_t)record.m_host_address + (uint64_t)record.m_size, ret,
record.m_process_address,
record.m_process_address + record.m_size);
return ret;
}
}
return LLDB_INVALID_ADDRESS;
}
IRExecutionUnit::AddrRange
IRExecutionUnit::GetRemoteRangeForLocal(lldb::addr_t local_address) {
for (AllocationRecord &record : m_records) {
if (local_address >= record.m_host_address &&
local_address < record.m_host_address + record.m_size) {
if (record.m_process_address == LLDB_INVALID_ADDRESS)
return AddrRange(0, 0);
return AddrRange(record.m_process_address, record.m_size);
}
}
return AddrRange(0, 0);
}
bool IRExecutionUnit::CommitOneAllocation(lldb::ProcessSP &process_sp,
Status &error,
AllocationRecord &record) {
if (record.m_process_address != LLDB_INVALID_ADDRESS) {
return true;
}
switch (record.m_sect_type) {
case lldb::eSectionTypeInvalid:
case lldb::eSectionTypeDWARFDebugAbbrev:
case lldb::eSectionTypeDWARFDebugAddr:
case lldb::eSectionTypeDWARFDebugAranges:
case lldb::eSectionTypeDWARFDebugCuIndex:
case lldb::eSectionTypeDWARFDebugFrame:
case lldb::eSectionTypeDWARFDebugInfo:
case lldb::eSectionTypeDWARFDebugLine:
case lldb::eSectionTypeDWARFDebugLoc:
case lldb::eSectionTypeDWARFDebugLocLists:
case lldb::eSectionTypeDWARFDebugMacInfo:
case lldb::eSectionTypeDWARFDebugPubNames:
case lldb::eSectionTypeDWARFDebugPubTypes:
case lldb::eSectionTypeDWARFDebugRanges:
case lldb::eSectionTypeDWARFDebugStr:
case lldb::eSectionTypeDWARFDebugStrOffsets:
case lldb::eSectionTypeDWARFAppleNames:
case lldb::eSectionTypeDWARFAppleTypes:
case lldb::eSectionTypeDWARFAppleNamespaces:
case lldb::eSectionTypeDWARFAppleObjC:
case lldb::eSectionTypeDWARFGNUDebugAltLink:
error.Clear();
break;
default:
const bool zero_memory = false;
if (auto address_or_error =
Malloc(record.m_size, record.m_alignment, record.m_permissions,
eAllocationPolicyProcessOnly, zero_memory))
record.m_process_address = *address_or_error;
else
error = Status::FromError(address_or_error.takeError());
break;
}
return error.Success();
}
bool IRExecutionUnit::CommitAllocations(lldb::ProcessSP &process_sp) {
bool ret = true;
lldb_private::Status err;
for (AllocationRecord &record : m_records) {
ret = CommitOneAllocation(process_sp, err, record);
if (!ret) {
break;
}
}
if (!ret) {
for (AllocationRecord &record : m_records) {
if (record.m_process_address != LLDB_INVALID_ADDRESS) {
Free(record.m_process_address, err);
record.m_process_address = LLDB_INVALID_ADDRESS;
}
}
}
return ret;
}
void IRExecutionUnit::ReportAllocations(llvm::ExecutionEngine &engine) {
m_reported_allocations = true;
for (AllocationRecord &record : m_records) {
if (record.m_process_address == LLDB_INVALID_ADDRESS)
continue;
if (record.m_section_id == eSectionIDInvalid)
continue;
engine.mapSectionAddress((void *)record.m_host_address,
record.m_process_address);
}
// Trigger re-application of relocations.
engine.finalizeObject();
}
bool IRExecutionUnit::WriteData(lldb::ProcessSP &process_sp) {
bool wrote_something = false;
for (AllocationRecord &record : m_records) {
if (record.m_process_address != LLDB_INVALID_ADDRESS) {
lldb_private::Status err;
WriteMemory(record.m_process_address, (uint8_t *)record.m_host_address,
record.m_size, err);
if (err.Success())
wrote_something = true;
}
}
return wrote_something;
}
void IRExecutionUnit::AllocationRecord::dump(Log *log) {
if (!log)
return;
LLDB_LOGF(log,
"[0x%llx+0x%llx]->0x%llx (alignment %d, section ID %d, name %s)",
(unsigned long long)m_host_address, (unsigned long long)m_size,
(unsigned long long)m_process_address, (unsigned)m_alignment,
(unsigned)m_section_id, m_name.c_str());
}
lldb::ByteOrder IRExecutionUnit::GetByteOrder() const {
ExecutionContext exe_ctx(GetBestExecutionContextScope());
return exe_ctx.GetByteOrder();
}
uint32_t IRExecutionUnit::GetAddressByteSize() const {
ExecutionContext exe_ctx(GetBestExecutionContextScope());
return exe_ctx.GetAddressByteSize();
}
void IRExecutionUnit::PopulateSymtab(lldb_private::ObjectFile *obj_file,
lldb_private::Symtab &symtab) {
// No symbols yet...
}
void IRExecutionUnit::PopulateSectionList(
lldb_private::ObjectFile *obj_file,
lldb_private::SectionList &section_list) {
for (AllocationRecord &record : m_records) {
if (record.m_size > 0) {
lldb::SectionSP section_sp(new lldb_private::Section(
obj_file->GetModule(), obj_file, record.m_section_id,
ConstString(record.m_name), record.m_sect_type,
record.m_process_address, record.m_size,
record.m_host_address, // file_offset (which is the host address for
// the data)
record.m_size, // file_size
0,
record.m_permissions)); // flags
section_list.AddSection(section_sp);
}
}
}
ArchSpec IRExecutionUnit::GetArchitecture() {
ExecutionContext exe_ctx(GetBestExecutionContextScope());
if(Target *target = exe_ctx.GetTargetPtr())
return target->GetArchitecture();
return ArchSpec();
}
lldb::ModuleSP IRExecutionUnit::GetJITModule() {
ExecutionContext exe_ctx(GetBestExecutionContextScope());
Target *target = exe_ctx.GetTargetPtr();
if (!target)
return nullptr;
auto Delegate = std::static_pointer_cast<lldb_private::ObjectFileJITDelegate>(
shared_from_this());
lldb::ModuleSP jit_module_sp =
lldb_private::Module::CreateModuleFromObjectFile<ObjectFileJIT>(Delegate);
if (!jit_module_sp)
return nullptr;
bool changed = false;
jit_module_sp->SetLoadAddress(*target, 0, true, changed);
return jit_module_sp;
}
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