Files
clang-p2996/lldb/source/Plugins/LanguageRuntime/CPlusPlus/ItaniumABI/ItaniumABILanguageRuntime.cpp
Greg Clayton c226778768 We have many radars showing that stepping through C++ code can result in slow steps.
One of the things slowing us down is that ItaniumABILanguageRuntime class doesn't cache vtable to types in a map. This causes us, on every step, for every variable, to read the first pointer in a C++ type that could be dynamic and lookup the symbol, possibly in every symbol file (some symbols files on Darwin can end up having thousands of .o files when using DWARF in .o files, so thousands of .o files are searched each time). 

This fix caches lldb_private::Address (the resolved vtable symbol address in section + offset format) to TypeAndOrName instances inside the one ItaniumABILanguageRuntime in a process. This allows caching of dynamic types and stops us from always doing deep searches in each file.

<rdar://problem/18890778>

llvm-svn: 270488
2016-05-23 20:37:24 +00:00

621 lines
25 KiB
C++

//===-- ItaniumABILanguageRuntime.cpp --------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "ItaniumABILanguageRuntime.h"
#include "lldb/Breakpoint/BreakpointLocation.h"
#include "lldb/Core/ConstString.h"
#include "lldb/Core/Error.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Mangled.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/Scalar.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Core/ValueObjectMemory.h"
#include "lldb/Interpreter/CommandObject.h"
#include "lldb/Interpreter/CommandObjectMultiword.h"
#include "lldb/Interpreter/CommandReturnObject.h"
#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Symbol/Symbol.h"
#include "lldb/Symbol/SymbolFile.h"
#include "lldb/Symbol/TypeList.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/SectionLoadList.h"
#include "lldb/Target/StopInfo.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include <vector>
using namespace lldb;
using namespace lldb_private;
static const char *vtable_demangled_prefix = "vtable for ";
bool
ItaniumABILanguageRuntime::CouldHaveDynamicValue (ValueObject &in_value)
{
const bool check_cxx = true;
const bool check_objc = false;
return in_value.GetCompilerType().IsPossibleDynamicType (NULL, check_cxx, check_objc);
}
TypeAndOrName
ItaniumABILanguageRuntime::GetTypeInfoFromVTableAddress(ValueObject &in_value, lldb::addr_t original_ptr,
lldb::addr_t vtable_load_addr)
{
if (m_process && vtable_load_addr != LLDB_INVALID_ADDRESS)
{
// Find the symbol that contains the "vtable_load_addr" address
Address vtable_addr;
Target &target = m_process->GetTarget();
if (!target.GetSectionLoadList().IsEmpty())
{
if (target.GetSectionLoadList().ResolveLoadAddress(vtable_load_addr, vtable_addr))
{
// See if we have cached info for this type already
TypeAndOrName type_info = GetDynamicTypeInfo(vtable_addr);
if (type_info)
return type_info;
SymbolContext sc;
target.GetImages().ResolveSymbolContextForAddress(vtable_addr, eSymbolContextSymbol, sc);
Symbol *symbol = sc.symbol;
if (symbol != NULL)
{
const char *name = symbol->GetMangled().GetDemangledName(lldb::eLanguageTypeC_plus_plus).AsCString();
if (name && strstr(name, vtable_demangled_prefix) == name)
{
Log *log (lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_OBJECT));
if (log)
log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has vtable symbol '%s'\n",
original_ptr,
in_value.GetTypeName().GetCString(),
name);
// We are a C++ class, that's good. Get the class name and look it up:
const char *class_name = name + strlen(vtable_demangled_prefix);
type_info.SetName(class_name);
const bool exact_match = true;
TypeList class_types;
uint32_t num_matches = 0;
// First look in the module that the vtable symbol came from
// and look for a single exact match.
llvm::DenseSet<SymbolFile *> searched_symbol_files;
if (sc.module_sp)
{
num_matches = sc.module_sp->FindTypes (sc,
ConstString(class_name),
exact_match,
1,
searched_symbol_files,
class_types);
}
// If we didn't find a symbol, then move on to the entire
// module list in the target and get as many unique matches
// as possible
if (num_matches == 0)
{
num_matches = target.GetImages().FindTypes(sc, ConstString(class_name), exact_match,
UINT32_MAX, searched_symbol_files, class_types);
}
lldb::TypeSP type_sp;
if (num_matches == 0)
{
if (log)
log->Printf("0x%16.16" PRIx64 ": is not dynamic\n", original_ptr);
return TypeAndOrName();
}
if (num_matches == 1)
{
type_sp = class_types.GetTypeAtIndex(0);
if (type_sp)
{
if (ClangASTContext::IsCXXClassType(type_sp->GetForwardCompilerType()))
{
if (log)
log->Printf("0x%16.16" PRIx64
": static-type = '%s' has dynamic type: uid={0x%" PRIx64
"}, type-name='%s'\n",
original_ptr, in_value.GetTypeName().AsCString(), type_sp->GetID(),
type_sp->GetName().GetCString());
type_info.SetTypeSP(type_sp);
}
}
}
else if (num_matches > 1)
{
size_t i;
if (log)
{
for (i = 0; i < num_matches; i++)
{
type_sp = class_types.GetTypeAtIndex(i);
if (type_sp)
{
if (log)
log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has multiple matching dynamic types: uid={0x%" PRIx64 "}, type-name='%s'\n",
original_ptr,
in_value.GetTypeName().AsCString(),
type_sp->GetID(),
type_sp->GetName().GetCString());
}
}
}
for (i = 0; i < num_matches; i++)
{
type_sp = class_types.GetTypeAtIndex(i);
if (type_sp)
{
if (ClangASTContext::IsCXXClassType(type_sp->GetForwardCompilerType()))
{
if (log)
log->Printf ("0x%16.16" PRIx64 ": static-type = '%s' has multiple matching dynamic types, picking this one: uid={0x%" PRIx64 "}, type-name='%s'\n",
original_ptr,
in_value.GetTypeName().AsCString(),
type_sp->GetID(),
type_sp->GetName().GetCString());
type_info.SetTypeSP(type_sp);
}
}
}
if (log && i == num_matches)
{
log->Printf("0x%16.16" PRIx64 ": static-type = '%s' has multiple matching dynamic "
"types, didn't find a C++ match\n",
original_ptr, in_value.GetTypeName().AsCString());
}
}
if (type_info)
SetDynamicTypeInfo(vtable_addr, type_info);
return type_info;
}
}
}
}
}
return TypeAndOrName();
}
bool
ItaniumABILanguageRuntime::GetDynamicTypeAndAddress(ValueObject &in_value, lldb::DynamicValueType use_dynamic,
TypeAndOrName &class_type_or_name, Address &dynamic_address,
Value::ValueType &value_type)
{
// For Itanium, if the type has a vtable pointer in the object, it will be at offset 0
// in the object. That will point to the "address point" within the vtable (not the beginning of the
// vtable.) We can then look up the symbol containing this "address point" and that symbol's name
// demangled will contain the full class name.
// The second pointer above the "address point" is the "offset_to_top". We'll use that to get the
// start of the value object which holds the dynamic type.
//
class_type_or_name.Clear();
value_type = Value::ValueType::eValueTypeScalar;
// Only a pointer or reference type can have a different dynamic and static type:
if (CouldHaveDynamicValue(in_value))
{
// First job, pull out the address at 0 offset from the object.
AddressType address_type;
lldb::addr_t original_ptr = in_value.GetPointerValue(&address_type);
if (original_ptr == LLDB_INVALID_ADDRESS)
return false;
ExecutionContext exe_ctx(in_value.GetExecutionContextRef());
Process *process = exe_ctx.GetProcessPtr();
if (process == nullptr)
return false;
Error error;
const lldb::addr_t vtable_address_point = process->ReadPointerFromMemory(original_ptr, error);
if (!error.Success() || vtable_address_point == LLDB_INVALID_ADDRESS)
{
return false;
}
class_type_or_name = GetTypeInfoFromVTableAddress(in_value, original_ptr, vtable_address_point);
if (class_type_or_name)
{
TypeSP type_sp = class_type_or_name.GetTypeSP();
// There can only be one type with a given name,
// so we've just found duplicate definitions, and this
// one will do as well as any other.
// We don't consider something to have a dynamic type if
// it is the same as the static type. So compare against
// the value we were handed.
if (type_sp)
{
if (ClangASTContext::AreTypesSame(in_value.GetCompilerType(), type_sp->GetForwardCompilerType()))
{
// The dynamic type we found was the same type,
// so we don't have a dynamic type here...
return false;
}
// The offset_to_top is two pointers above the vtable pointer.
const uint32_t addr_byte_size = process->GetAddressByteSize();
const lldb::addr_t offset_to_top_location = vtable_address_point - 2 * addr_byte_size;
// Watch for underflow, offset_to_top_location should be less than vtable_address_point
if (offset_to_top_location >= vtable_address_point)
return false;
const int64_t offset_to_top =
process->ReadSignedIntegerFromMemory(offset_to_top_location, addr_byte_size, INT64_MIN, error);
if (offset_to_top == INT64_MIN)
return false;
// So the dynamic type is a value that starts at offset_to_top
// above the original address.
lldb::addr_t dynamic_addr = original_ptr + offset_to_top;
if (!process->GetTarget().GetSectionLoadList().ResolveLoadAddress(dynamic_addr, dynamic_address))
{
dynamic_address.SetRawAddress(dynamic_addr);
}
return true;
}
}
}
return class_type_or_name.IsEmpty() == false;
}
TypeAndOrName
ItaniumABILanguageRuntime::FixUpDynamicType(const TypeAndOrName& type_and_or_name,
ValueObject& static_value)
{
CompilerType static_type(static_value.GetCompilerType());
Flags static_type_flags(static_type.GetTypeInfo());
TypeAndOrName ret(type_and_or_name);
if (type_and_or_name.HasType())
{
// The type will always be the type of the dynamic object. If our parent's type was a pointer,
// then our type should be a pointer to the type of the dynamic object. If a reference, then the original type
// should be okay...
CompilerType orig_type = type_and_or_name.GetCompilerType();
CompilerType corrected_type = orig_type;
if (static_type_flags.AllSet(eTypeIsPointer))
corrected_type = orig_type.GetPointerType ();
else if (static_type_flags.AllSet(eTypeIsReference))
corrected_type = orig_type.GetLValueReferenceType();
ret.SetCompilerType(corrected_type);
}
else
{
// If we are here we need to adjust our dynamic type name to include the correct & or * symbol
std::string corrected_name (type_and_or_name.GetName().GetCString());
if (static_type_flags.AllSet(eTypeIsPointer))
corrected_name.append(" *");
else if (static_type_flags.AllSet(eTypeIsReference))
corrected_name.append(" &");
// the parent type should be a correctly pointer'ed or referenc'ed type
ret.SetCompilerType(static_type);
ret.SetName(corrected_name.c_str());
}
return ret;
}
bool
ItaniumABILanguageRuntime::IsVTableName (const char *name)
{
if (name == NULL)
return false;
// Can we maybe ask Clang about this?
if (strstr (name, "_vptr$") == name)
return true;
else
return false;
}
//------------------------------------------------------------------
// Static Functions
//------------------------------------------------------------------
LanguageRuntime *
ItaniumABILanguageRuntime::CreateInstance (Process *process, lldb::LanguageType language)
{
// FIXME: We have to check the process and make sure we actually know that this process supports
// the Itanium ABI.
if (language == eLanguageTypeC_plus_plus ||
language == eLanguageTypeC_plus_plus_03 ||
language == eLanguageTypeC_plus_plus_11 ||
language == eLanguageTypeC_plus_plus_14)
return new ItaniumABILanguageRuntime (process);
else
return NULL;
}
class CommandObjectMultiwordItaniumABI_Demangle : public CommandObjectParsed
{
public:
CommandObjectMultiwordItaniumABI_Demangle (CommandInterpreter &interpreter) :
CommandObjectParsed (interpreter,
"demangle",
"Demangle a C++ mangled name.",
"language cplusplus demangle")
{
CommandArgumentEntry arg;
CommandArgumentData index_arg;
// Define the first (and only) variant of this arg.
index_arg.arg_type = eArgTypeSymbol;
index_arg.arg_repetition = eArgRepeatPlus;
// There is only one variant this argument could be; put it into the argument entry.
arg.push_back (index_arg);
// Push the data for the first argument into the m_arguments vector.
m_arguments.push_back (arg);
}
~CommandObjectMultiwordItaniumABI_Demangle() override = default;
protected:
bool
DoExecute(Args& command, CommandReturnObject &result) override
{
bool demangled_any = false;
bool error_any = false;
for (size_t i = 0; i < command.GetArgumentCount(); i++)
{
auto arg = command.GetArgumentAtIndex(i);
if (arg && *arg)
{
ConstString mangled_cs(arg);
// the actual Mangled class should be strict about this, but on the command line
// if you're copying mangled names out of 'nm' on Darwin, they will come out with
// an extra underscore - be willing to strip this on behalf of the user
// This is the moral equivalent of the -_/-n options to c++filt
if (mangled_cs.GetStringRef().startswith("__Z"))
mangled_cs.SetCString(arg+1);
Mangled mangled(mangled_cs, true);
if (mangled.GuessLanguage() == lldb::eLanguageTypeC_plus_plus)
{
ConstString demangled(mangled.GetDisplayDemangledName(lldb::eLanguageTypeC_plus_plus));
demangled_any = true;
result.AppendMessageWithFormat("%s ---> %s\n", arg, demangled.GetCString());
}
else
{
error_any = true;
result.AppendErrorWithFormat("%s is not a valid C++ mangled name\n", arg);
}
}
}
result.SetStatus(error_any ? lldb::eReturnStatusFailed :
(demangled_any ? lldb::eReturnStatusSuccessFinishResult : lldb::eReturnStatusSuccessFinishNoResult));
return result.Succeeded();
}
};
class CommandObjectMultiwordItaniumABI : public CommandObjectMultiword
{
public:
CommandObjectMultiwordItaniumABI (CommandInterpreter &interpreter) :
CommandObjectMultiword (interpreter,
"cplusplus",
"A set of commands for operating on the C++ Language Runtime.",
"cplusplus <subcommand> [<subcommand-options>]")
{
LoadSubCommand ("demangle", CommandObjectSP (new CommandObjectMultiwordItaniumABI_Demangle (interpreter)));
}
~CommandObjectMultiwordItaniumABI() override = default;
};
void
ItaniumABILanguageRuntime::Initialize()
{
PluginManager::RegisterPlugin (GetPluginNameStatic(),
"Itanium ABI for the C++ language",
CreateInstance,
[] (CommandInterpreter& interpreter) -> lldb::CommandObjectSP {
return CommandObjectSP(new CommandObjectMultiwordItaniumABI(interpreter));
});
}
void
ItaniumABILanguageRuntime::Terminate()
{
PluginManager::UnregisterPlugin (CreateInstance);
}
lldb_private::ConstString
ItaniumABILanguageRuntime::GetPluginNameStatic()
{
static ConstString g_name("itanium");
return g_name;
}
//------------------------------------------------------------------
// PluginInterface protocol
//------------------------------------------------------------------
lldb_private::ConstString
ItaniumABILanguageRuntime::GetPluginName()
{
return GetPluginNameStatic();
}
uint32_t
ItaniumABILanguageRuntime::GetPluginVersion()
{
return 1;
}
BreakpointResolverSP
ItaniumABILanguageRuntime::CreateExceptionResolver (Breakpoint *bkpt, bool catch_bp, bool throw_bp)
{
return CreateExceptionResolver (bkpt, catch_bp, throw_bp, false);
}
BreakpointResolverSP
ItaniumABILanguageRuntime::CreateExceptionResolver (Breakpoint *bkpt, bool catch_bp, bool throw_bp, bool for_expressions)
{
// One complication here is that most users DON'T want to stop at __cxa_allocate_expression, but until we can do
// anything better with predicting unwinding the expression parser does. So we have two forms of the exception
// breakpoints, one for expressions that leaves out __cxa_allocate_exception, and one that includes it.
// The SetExceptionBreakpoints does the latter, the CreateExceptionBreakpoint in the runtime the former.
static const char *g_catch_name = "__cxa_begin_catch";
static const char *g_throw_name1 = "__cxa_throw";
static const char *g_throw_name2 = "__cxa_rethrow";
static const char *g_exception_throw_name = "__cxa_allocate_exception";
std::vector<const char *> exception_names;
exception_names.reserve(4);
if (catch_bp)
exception_names.push_back(g_catch_name);
if (throw_bp)
{
exception_names.push_back(g_throw_name1);
exception_names.push_back(g_throw_name2);
}
if (for_expressions)
exception_names.push_back(g_exception_throw_name);
BreakpointResolverSP resolver_sp (new BreakpointResolverName (bkpt,
exception_names.data(),
exception_names.size(),
eFunctionNameTypeBase,
eLanguageTypeUnknown,
0,
eLazyBoolNo));
return resolver_sp;
}
lldb::SearchFilterSP
ItaniumABILanguageRuntime::CreateExceptionSearchFilter ()
{
Target &target = m_process->GetTarget();
if (target.GetArchitecture().GetTriple().getVendor() == llvm::Triple::Apple)
{
// Limit the number of modules that are searched for these breakpoints for
// Apple binaries.
FileSpecList filter_modules;
filter_modules.Append(FileSpec("libc++abi.dylib", false));
filter_modules.Append(FileSpec("libSystem.B.dylib", false));
return target.GetSearchFilterForModuleList(&filter_modules);
}
else
{
return LanguageRuntime::CreateExceptionSearchFilter();
}
}
lldb::BreakpointSP
ItaniumABILanguageRuntime::CreateExceptionBreakpoint (bool catch_bp,
bool throw_bp,
bool for_expressions,
bool is_internal)
{
Target &target = m_process->GetTarget();
FileSpecList filter_modules;
BreakpointResolverSP exception_resolver_sp = CreateExceptionResolver (NULL, catch_bp, throw_bp, for_expressions);
SearchFilterSP filter_sp (CreateExceptionSearchFilter ());
const bool hardware = false;
const bool resolve_indirect_functions = false;
return target.CreateBreakpoint (filter_sp, exception_resolver_sp, is_internal, hardware, resolve_indirect_functions);
}
void
ItaniumABILanguageRuntime::SetExceptionBreakpoints ()
{
if (!m_process)
return;
const bool catch_bp = false;
const bool throw_bp = true;
const bool is_internal = true;
const bool for_expressions = true;
// For the exception breakpoints set by the Expression parser, we'll be a little more aggressive and
// stop at exception allocation as well.
if (m_cxx_exception_bp_sp)
{
m_cxx_exception_bp_sp->SetEnabled (true);
}
else
{
m_cxx_exception_bp_sp = CreateExceptionBreakpoint (catch_bp, throw_bp, for_expressions, is_internal);
if (m_cxx_exception_bp_sp)
m_cxx_exception_bp_sp->SetBreakpointKind("c++ exception");
}
}
void
ItaniumABILanguageRuntime::ClearExceptionBreakpoints ()
{
if (!m_process)
return;
if (m_cxx_exception_bp_sp)
{
m_cxx_exception_bp_sp->SetEnabled (false);
}
}
bool
ItaniumABILanguageRuntime::ExceptionBreakpointsAreSet ()
{
return m_cxx_exception_bp_sp && m_cxx_exception_bp_sp->IsEnabled();
}
bool
ItaniumABILanguageRuntime::ExceptionBreakpointsExplainStop (lldb::StopInfoSP stop_reason)
{
if (!m_process)
return false;
if (!stop_reason ||
stop_reason->GetStopReason() != eStopReasonBreakpoint)
return false;
uint64_t break_site_id = stop_reason->GetValue();
return m_process->GetBreakpointSiteList().BreakpointSiteContainsBreakpoint(break_site_id,
m_cxx_exception_bp_sp->GetID());
}
TypeAndOrName
ItaniumABILanguageRuntime::GetDynamicTypeInfo(const lldb_private::Address &vtable_addr)
{
std::lock_guard<std::mutex> locker(m_dynamic_type_map_mutex);
DynamicTypeCache::const_iterator pos = m_dynamic_type_map.find(vtable_addr);
if (pos == m_dynamic_type_map.end())
return TypeAndOrName();
else
return pos->second;
}
void
ItaniumABILanguageRuntime::SetDynamicTypeInfo(const lldb_private::Address &vtable_addr, const TypeAndOrName &type_info)
{
std::lock_guard<std::mutex> locker(m_dynamic_type_map_mutex);
m_dynamic_type_map[vtable_addr] = type_info;
}