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llvm-project/lldb/source/Symbol/Symbol.cpp

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//===-- Symbol.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 "lldb/Symbol/Symbol.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/Section.h"
#include "lldb/Symbol/Function.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Symbol/SymbolVendor.h"
#include "lldb/Symbol/Symtab.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/Stream.h"
using namespace lldb;
using namespace lldb_private;
Symbol::Symbol()
: SymbolContextScope(), m_type_data_resolved(false), m_is_synthetic(false),
m_is_debug(false), m_is_external(false), m_size_is_sibling(false),
m_size_is_synthesized(false), m_size_is_valid(false),
m_demangled_is_synthesized(false), m_contains_linker_annotations(false),
m_is_weak(false), m_type(eSymbolTypeInvalid), m_mangled(),
m_addr_range() {}
Symbol::Symbol(uint32_t symID, llvm::StringRef name, SymbolType type, bool external,
bool is_debug, bool is_trampoline, bool is_artificial,
const lldb::SectionSP &section_sp, addr_t offset, addr_t size,
bool size_is_valid, bool contains_linker_annotations,
uint32_t flags)
: SymbolContextScope(), m_uid(symID), m_type_data(0),
m_type_data_resolved(false), m_is_synthetic(is_artificial),
m_is_debug(is_debug), m_is_external(external), m_size_is_sibling(false),
m_size_is_synthesized(false), m_size_is_valid(size_is_valid || size > 0),
m_demangled_is_synthesized(false),
m_contains_linker_annotations(contains_linker_annotations),
m_is_weak(false), m_type(type),
m_mangled(name),
m_addr_range(section_sp, offset, size), m_flags(flags) {}
Symbol::Symbol(uint32_t symID, const Mangled &mangled, SymbolType type,
bool external, bool is_debug, bool is_trampoline,
bool is_artificial, const AddressRange &range,
bool size_is_valid, bool contains_linker_annotations,
uint32_t flags)
: SymbolContextScope(), m_uid(symID), m_type_data(0),
m_type_data_resolved(false), m_is_synthetic(is_artificial),
m_is_debug(is_debug), m_is_external(external), m_size_is_sibling(false),
m_size_is_synthesized(false),
m_size_is_valid(size_is_valid || range.GetByteSize() > 0),
m_demangled_is_synthesized(false),
m_contains_linker_annotations(contains_linker_annotations),
m_is_weak(false), m_type(type), m_mangled(mangled), m_addr_range(range),
m_flags(flags) {}
Symbol::Symbol(const Symbol &rhs)
: SymbolContextScope(rhs), m_uid(rhs.m_uid), m_type_data(rhs.m_type_data),
m_type_data_resolved(rhs.m_type_data_resolved),
m_is_synthetic(rhs.m_is_synthetic), m_is_debug(rhs.m_is_debug),
m_is_external(rhs.m_is_external),
m_size_is_sibling(rhs.m_size_is_sibling), m_size_is_synthesized(false),
m_size_is_valid(rhs.m_size_is_valid),
m_demangled_is_synthesized(rhs.m_demangled_is_synthesized),
m_contains_linker_annotations(rhs.m_contains_linker_annotations),
m_is_weak(rhs.m_is_weak), m_type(rhs.m_type), m_mangled(rhs.m_mangled),
m_addr_range(rhs.m_addr_range), m_flags(rhs.m_flags) {}
const Symbol &Symbol::operator=(const Symbol &rhs) {
if (this != &rhs) {
SymbolContextScope::operator=(rhs);
m_uid = rhs.m_uid;
m_type_data = rhs.m_type_data;
m_type_data_resolved = rhs.m_type_data_resolved;
m_is_synthetic = rhs.m_is_synthetic;
m_is_debug = rhs.m_is_debug;
m_is_external = rhs.m_is_external;
m_size_is_sibling = rhs.m_size_is_sibling;
m_size_is_synthesized = rhs.m_size_is_sibling;
m_size_is_valid = rhs.m_size_is_valid;
m_demangled_is_synthesized = rhs.m_demangled_is_synthesized;
m_contains_linker_annotations = rhs.m_contains_linker_annotations;
m_is_weak = rhs.m_is_weak;
m_type = rhs.m_type;
m_mangled = rhs.m_mangled;
m_addr_range = rhs.m_addr_range;
m_flags = rhs.m_flags;
}
return *this;
}
void Symbol::Clear() {
m_uid = UINT32_MAX;
m_mangled.Clear();
m_type_data = 0;
m_type_data_resolved = false;
m_is_synthetic = false;
m_is_debug = false;
m_is_external = false;
m_size_is_sibling = false;
m_size_is_synthesized = false;
m_size_is_valid = false;
m_demangled_is_synthesized = false;
m_contains_linker_annotations = false;
m_is_weak = false;
m_type = eSymbolTypeInvalid;
m_flags = 0;
m_addr_range.Clear();
}
bool Symbol::ValueIsAddress() const {
return m_addr_range.GetBaseAddress().GetSection().get() != nullptr ||
m_type == eSymbolTypeAbsolute;
}
ConstString Symbol::GetDisplayName() const {
return GetMangled().GetDisplayDemangledName();
}
ConstString Symbol::GetReExportedSymbolName() const {
if (m_type == eSymbolTypeReExported) {
// For eSymbolTypeReExported, the "const char *" from a ConstString is used
// as the offset in the address range base address. We can then make this
// back into a string that is the re-exported name.
intptr_t str_ptr = m_addr_range.GetBaseAddress().GetOffset();
if (str_ptr != 0)
return ConstString((const char *)str_ptr);
else
return GetName();
}
return ConstString();
}
FileSpec Symbol::GetReExportedSymbolSharedLibrary() const {
if (m_type == eSymbolTypeReExported) {
// For eSymbolTypeReExported, the "const char *" from a ConstString is used
// as the offset in the address range base address. We can then make this
// back into a string that is the re-exported name.
intptr_t str_ptr = m_addr_range.GetByteSize();
if (str_ptr != 0)
return FileSpec((const char *)str_ptr);
}
return FileSpec();
}
void Symbol::SetReExportedSymbolName(ConstString name) {
SetType(eSymbolTypeReExported);
// For eSymbolTypeReExported, the "const char *" from a ConstString is used
// as the offset in the address range base address.
m_addr_range.GetBaseAddress().SetOffset((uintptr_t)name.GetCString());
}
bool Symbol::SetReExportedSymbolSharedLibrary(const FileSpec &fspec) {
if (m_type == eSymbolTypeReExported) {
// For eSymbolTypeReExported, the "const char *" from a ConstString is used
// as the offset in the address range base address.
m_addr_range.SetByteSize(
(uintptr_t)ConstString(fspec.GetPath().c_str()).GetCString());
return true;
}
return false;
}
uint32_t Symbol::GetSiblingIndex() const {
return m_size_is_sibling ? m_addr_range.GetByteSize() : UINT32_MAX;
}
bool Symbol::IsTrampoline() const { return m_type == eSymbolTypeTrampoline; }
bool Symbol::IsIndirect() const { return m_type == eSymbolTypeResolver; }
void Symbol::GetDescription(Stream *s, lldb::DescriptionLevel level,
Target *target) const {
s->Printf("id = {0x%8.8x}", m_uid);
if (m_addr_range.GetBaseAddress().GetSection()) {
if (ValueIsAddress()) {
const lldb::addr_t byte_size = GetByteSize();
if (byte_size > 0) {
s->PutCString(", range = ");
m_addr_range.Dump(s, target, Address::DumpStyleLoadAddress,
Address::DumpStyleFileAddress);
} else {
s->PutCString(", address = ");
m_addr_range.GetBaseAddress().Dump(s, target,
Address::DumpStyleLoadAddress,
Address::DumpStyleFileAddress);
}
} else
s->Printf(", value = 0x%16.16" PRIx64,
m_addr_range.GetBaseAddress().GetOffset());
} else {
if (m_size_is_sibling)
s->Printf(", sibling = %5" PRIu64,
m_addr_range.GetBaseAddress().GetOffset());
else
s->Printf(", value = 0x%16.16" PRIx64,
m_addr_range.GetBaseAddress().GetOffset());
}
ConstString demangled = GetMangled().GetDemangledName();
if (demangled)
s->Printf(", name=\"%s\"", demangled.AsCString());
if (m_mangled.GetMangledName())
s->Printf(", mangled=\"%s\"", m_mangled.GetMangledName().AsCString());
}
void Symbol::Dump(Stream *s, Target *target, uint32_t index,
Mangled::NamePreference name_preference) const {
s->Printf("[%5u] %6u %c%c%c %-15s ", index, GetID(), m_is_debug ? 'D' : ' ',
m_is_synthetic ? 'S' : ' ', m_is_external ? 'X' : ' ',
GetTypeAsString());
// Make sure the size of the symbol is up to date before dumping
GetByteSize();
ConstString name = GetMangled().GetName(name_preference);
if (ValueIsAddress()) {
if (!m_addr_range.GetBaseAddress().Dump(s, nullptr,
Address::DumpStyleFileAddress))
s->Printf("%*s", 18, "");
s->PutChar(' ');
if (!m_addr_range.GetBaseAddress().Dump(s, target,
Address::DumpStyleLoadAddress))
s->Printf("%*s", 18, "");
const char *format = m_size_is_sibling ? " Sibling -> [%5llu] 0x%8.8x %s\n"
: " 0x%16.16" PRIx64 " 0x%8.8x %s\n";
s->Printf(format, GetByteSize(), m_flags, name.AsCString(""));
} else if (m_type == eSymbolTypeReExported) {
s->Printf(
" 0x%8.8x %s",
m_flags, name.AsCString(""));
ConstString reexport_name = GetReExportedSymbolName();
intptr_t shlib = m_addr_range.GetByteSize();
if (shlib)
s->Printf(" -> %s`%s\n", (const char *)shlib, reexport_name.GetCString());
else
s->Printf(" -> %s\n", reexport_name.GetCString());
} else {
const char *format =
m_size_is_sibling
? "0x%16.16" PRIx64
" Sibling -> [%5llu] 0x%8.8x %s\n"
: "0x%16.16" PRIx64 " 0x%16.16" PRIx64
" 0x%8.8x %s\n";
s->Printf(format, m_addr_range.GetBaseAddress().GetOffset(), GetByteSize(),
m_flags, name.AsCString(""));
}
}
uint32_t Symbol::GetPrologueByteSize() {
if (m_type == eSymbolTypeCode || m_type == eSymbolTypeResolver) {
if (!m_type_data_resolved) {
m_type_data_resolved = true;
const Address &base_address = m_addr_range.GetBaseAddress();
Function *function = base_address.CalculateSymbolContextFunction();
if (function) {
// Functions have line entries which can also potentially have end of
// prologue information. So if this symbol points to a function, use
// the prologue information from there.
m_type_data = function->GetPrologueByteSize();
} else {
ModuleSP module_sp(base_address.GetModule());
SymbolContext sc;
if (module_sp) {
uint32_t resolved_flags = module_sp->ResolveSymbolContextForAddress(
base_address, eSymbolContextLineEntry, sc);
if (resolved_flags & eSymbolContextLineEntry) {
// Default to the end of the first line entry.
m_type_data = sc.line_entry.range.GetByteSize();
// Set address for next line.
Address addr(base_address);
addr.Slide(m_type_data);
// Check the first few instructions and look for one that has a
// line number that is different than the first entry. This is also
// done in Function::GetPrologueByteSize().
uint16_t total_offset = m_type_data;
for (int idx = 0; idx < 6; ++idx) {
SymbolContext sc_temp;
resolved_flags = module_sp->ResolveSymbolContextForAddress(
addr, eSymbolContextLineEntry, sc_temp);
// Make sure we got line number information...
if (!(resolved_flags & eSymbolContextLineEntry))
break;
// If this line number is different than our first one, use it
// and we're done.
if (sc_temp.line_entry.line != sc.line_entry.line) {
m_type_data = total_offset;
break;
}
// Slide addr up to the next line address.
addr.Slide(sc_temp.line_entry.range.GetByteSize());
total_offset += sc_temp.line_entry.range.GetByteSize();
// If we've gone too far, bail out.
if (total_offset >= m_addr_range.GetByteSize())
break;
}
// Sanity check - this may be a function in the middle of code that
// has debug information, but not for this symbol. So the line
// entries surrounding us won't lie inside our function. In that
// case, the line entry will be bigger than we are, so we do that
// quick check and if that is true, we just return 0.
if (m_type_data >= m_addr_range.GetByteSize())
m_type_data = 0;
} else {
// TODO: expose something in Process to figure out the
// size of a function prologue.
m_type_data = 0;
}
}
}
}
return m_type_data;
}
return 0;
}
bool Symbol::Compare(ConstString name, SymbolType type) const {
if (type == eSymbolTypeAny || m_type == type) {
const Mangled &mangled = GetMangled();
return mangled.GetMangledName() == name ||
mangled.GetDemangledName() == name;
}
return false;
}
#define ENUM_TO_CSTRING(x) \
case eSymbolType##x: \
return #x;
const char *Symbol::GetTypeAsString() const {
switch (m_type) {
ENUM_TO_CSTRING(Invalid);
ENUM_TO_CSTRING(Absolute);
ENUM_TO_CSTRING(Code);
ENUM_TO_CSTRING(Resolver);
ENUM_TO_CSTRING(Data);
ENUM_TO_CSTRING(Trampoline);
ENUM_TO_CSTRING(Runtime);
ENUM_TO_CSTRING(Exception);
ENUM_TO_CSTRING(SourceFile);
ENUM_TO_CSTRING(HeaderFile);
ENUM_TO_CSTRING(ObjectFile);
ENUM_TO_CSTRING(CommonBlock);
ENUM_TO_CSTRING(Block);
ENUM_TO_CSTRING(Local);
ENUM_TO_CSTRING(Param);
ENUM_TO_CSTRING(Variable);
ENUM_TO_CSTRING(VariableType);
ENUM_TO_CSTRING(LineEntry);
ENUM_TO_CSTRING(LineHeader);
ENUM_TO_CSTRING(ScopeBegin);
ENUM_TO_CSTRING(ScopeEnd);
ENUM_TO_CSTRING(Additional);
ENUM_TO_CSTRING(Compiler);
ENUM_TO_CSTRING(Instrumentation);
ENUM_TO_CSTRING(Undefined);
ENUM_TO_CSTRING(ObjCClass);
ENUM_TO_CSTRING(ObjCMetaClass);
ENUM_TO_CSTRING(ObjCIVar);
ENUM_TO_CSTRING(ReExported);
default:
break;
}
return "<unknown SymbolType>";
}
void Symbol::CalculateSymbolContext(SymbolContext *sc) {
// Symbols can reconstruct the symbol and the module in the symbol context
sc->symbol = this;
if (ValueIsAddress())
sc->module_sp = GetAddressRef().GetModule();
else
sc->module_sp.reset();
}
ModuleSP Symbol::CalculateSymbolContextModule() {
if (ValueIsAddress())
return GetAddressRef().GetModule();
return ModuleSP();
}
Symbol *Symbol::CalculateSymbolContextSymbol() { return this; }
void Symbol::DumpSymbolContext(Stream *s) {
bool dumped_module = false;
if (ValueIsAddress()) {
ModuleSP module_sp(GetAddressRef().GetModule());
if (module_sp) {
dumped_module = true;
module_sp->DumpSymbolContext(s);
}
}
if (dumped_module)
s->PutCString(", ");
s->Printf("Symbol{0x%8.8x}", GetID());
}
lldb::addr_t Symbol::GetByteSize() const { return m_addr_range.GetByteSize(); }
Symbol *Symbol::ResolveReExportedSymbolInModuleSpec(
Target &target, ConstString &reexport_name, ModuleSpec &module_spec,
ModuleList &seen_modules) const {
ModuleSP module_sp;
if (module_spec.GetFileSpec()) {
// Try searching for the module file spec first using the full path
module_sp = target.GetImages().FindFirstModule(module_spec);
if (!module_sp) {
// Next try and find the module by basename in case environment variables
// or other runtime trickery causes shared libraries to be loaded from
// alternate paths
module_spec.GetFileSpec().GetDirectory().Clear();
module_sp = target.GetImages().FindFirstModule(module_spec);
}
}
if (module_sp) {
// There should not be cycles in the reexport list, but we don't want to
// crash if there are so make sure we haven't seen this before:
if (!seen_modules.AppendIfNeeded(module_sp))
return nullptr;
lldb_private::SymbolContextList sc_list;
module_sp->FindSymbolsWithNameAndType(reexport_name, eSymbolTypeAny,
sc_list);
const size_t num_scs = sc_list.GetSize();
if (num_scs > 0) {
for (size_t i = 0; i < num_scs; ++i) {
lldb_private::SymbolContext sc;
if (sc_list.GetContextAtIndex(i, sc)) {
if (sc.symbol->IsExternal())
return sc.symbol;
}
}
}
// If we didn't find the symbol in this module, it may be because this
// module re-exports some whole other library. We have to search those as
// well:
seen_modules.Append(module_sp);
FileSpecList reexported_libraries =
module_sp->GetObjectFile()->GetReExportedLibraries();
size_t num_reexported_libraries = reexported_libraries.GetSize();
for (size_t idx = 0; idx < num_reexported_libraries; idx++) {
ModuleSpec reexported_module_spec;
reexported_module_spec.GetFileSpec() =
reexported_libraries.GetFileSpecAtIndex(idx);
Symbol *result_symbol = ResolveReExportedSymbolInModuleSpec(
target, reexport_name, reexported_module_spec, seen_modules);
if (result_symbol)
return result_symbol;
}
}
return nullptr;
}
Symbol *Symbol::ResolveReExportedSymbol(Target &target) const {
ConstString reexport_name(GetReExportedSymbolName());
if (reexport_name) {
ModuleSpec module_spec;
ModuleList seen_modules;
module_spec.GetFileSpec() = GetReExportedSymbolSharedLibrary();
if (module_spec.GetFileSpec()) {
return ResolveReExportedSymbolInModuleSpec(target, reexport_name,
module_spec, seen_modules);
}
}
return nullptr;
}
lldb::addr_t Symbol::GetFileAddress() const {
if (ValueIsAddress())
return GetAddressRef().GetFileAddress();
else
return LLDB_INVALID_ADDRESS;
}
lldb::addr_t Symbol::GetLoadAddress(Target *target) const {
if (ValueIsAddress())
return GetAddressRef().GetLoadAddress(target);
else
return LLDB_INVALID_ADDRESS;
}
ConstString Symbol::GetName() const { return GetMangled().GetName(); }
ConstString Symbol::GetNameNoArguments() const {
return GetMangled().GetName(Mangled::ePreferDemangledWithoutArguments);
}
lldb::addr_t Symbol::ResolveCallableAddress(Target &target) const {
if (GetType() == lldb::eSymbolTypeUndefined)
return LLDB_INVALID_ADDRESS;
Address func_so_addr;
bool is_indirect = IsIndirect();
if (GetType() == eSymbolTypeReExported) {
Symbol *reexported_symbol = ResolveReExportedSymbol(target);
if (reexported_symbol) {
func_so_addr = reexported_symbol->GetAddress();
is_indirect = reexported_symbol->IsIndirect();
}
} else {
func_so_addr = GetAddress();
is_indirect = IsIndirect();
}
if (func_so_addr.IsValid()) {
if (!target.GetProcessSP() && is_indirect) {
// can't resolve indirect symbols without calling a function...
return LLDB_INVALID_ADDRESS;
}
lldb::addr_t load_addr =
func_so_addr.GetCallableLoadAddress(&target, is_indirect);
if (load_addr != LLDB_INVALID_ADDRESS) {
return load_addr;
}
}
return LLDB_INVALID_ADDRESS;
}
lldb::DisassemblerSP Symbol::GetInstructions(const ExecutionContext &exe_ctx,
const char *flavor,
bool prefer_file_cache) {
ModuleSP module_sp(m_addr_range.GetBaseAddress().GetModule());
if (module_sp && exe_ctx.HasTargetScope()) {
return Disassembler::DisassembleRange(module_sp->GetArchitecture(), nullptr,
flavor, exe_ctx.GetTargetRef(),
m_addr_range, !prefer_file_cache);
}
return lldb::DisassemblerSP();
}
bool Symbol::GetDisassembly(const ExecutionContext &exe_ctx, const char *flavor,
bool prefer_file_cache, Stream &strm) {
lldb::DisassemblerSP disassembler_sp =
GetInstructions(exe_ctx, flavor, prefer_file_cache);
if (disassembler_sp) {
const bool show_address = true;
const bool show_bytes = false;
disassembler_sp->GetInstructionList().Dump(&strm, show_address, show_bytes,
&exe_ctx);
return true;
}
return false;
}
bool Symbol::ContainsFileAddress(lldb::addr_t file_addr) const {
return m_addr_range.ContainsFileAddress(file_addr);
}
bool Symbol::IsSyntheticWithAutoGeneratedName() const {
if (!IsSynthetic())
return false;
if (!m_mangled)
return true;
ConstString demangled = m_mangled.GetDemangledName();
return demangled.GetStringRef().startswith(GetSyntheticSymbolPrefix());
}
void Symbol::SynthesizeNameIfNeeded() const {
if (m_is_synthetic && !m_mangled) {
// Synthetic symbol names don't mean anything, but they do uniquely
// identify individual symbols so we give them a unique name. The name
// starts with the synthetic symbol prefix, followed by a unique number.
// Typically the UserID of a real symbol is the symbol table index of the
// symbol in the object file's symbol table(s), so it will be the same
// every time you read in the object file. We want the same persistence for
// synthetic symbols so that users can identify them across multiple debug
// sessions, to understand crashes in those symbols and to reliably set
// breakpoints on them.
llvm::SmallString<256> name;
llvm::raw_svector_ostream os(name);
os << GetSyntheticSymbolPrefix() << GetID();
m_mangled.SetDemangledName(ConstString(os.str()));
}
}
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