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llvm-project/lldb/source/Plugins/LanguageRuntime/CPlusPlus/ItaniumABI/ItaniumABILanguageRuntime.cpp

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//===-- 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/Module.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/Scalar.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Core/ValueObjectMemory.h"
#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.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 *pluginName = "ItaniumABILanguageRuntime";
static const char *pluginDesc = "Itanium ABI for the C++ language";
static const char *pluginShort = "language.itanium";
static const char *vtable_demangled_prefix = "vtable for ";
bool
ItaniumABILanguageRuntime::CouldHaveDynamicValue (ValueObject &in_value)
{
return in_value.IsPossibleCPlusPlusDynamicType();
}
bool
ItaniumABILanguageRuntime::GetDynamicTypeAndAddress (ValueObject &in_value,
lldb::DynamicValueType use_dynamic,
TypeAndOrName &class_type_or_name,
Address &dynamic_address)
{
// 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.
//
// 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());
Target *target = exe_ctx.GetTargetPtr();
Process *process = exe_ctx.GetProcessPtr();
char memory_buffer[16];
DataExtractor data(memory_buffer, sizeof(memory_buffer),
process->GetByteOrder(),
process->GetAddressByteSize());
size_t address_byte_size = process->GetAddressByteSize();
Error error;
size_t bytes_read = process->ReadMemory (original_ptr,
memory_buffer,
address_byte_size,
error);
if (!error.Success() || (bytes_read != address_byte_size))
{
return false;
}
uint32_t offset_ptr = 0;
lldb::addr_t vtable_address_point = data.GetAddress (&offset_ptr);
if (offset_ptr == 0)
return false;
// Now find the symbol that contains this address:
SymbolContext sc;
Address address_point_address;
if (target && !target->GetSectionLoadList().IsEmpty())
{
if (target->GetSectionLoadList().ResolveLoadAddress (vtable_address_point, address_point_address))
{
target->GetImages().ResolveSymbolContextForAddress (address_point_address, eSymbolContextSymbol, sc);
Symbol *symbol = sc.symbol;
if (symbol != NULL)
{
const char *name = symbol->GetMangled().GetDemangledName().AsCString();
if (strstr(name, vtable_demangled_prefix) == name)
{
LogSP log (lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_OBJECT));
if (log)
log->Printf ("0x%16.16llx: 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);
class_type_or_name.SetName (class_name);
const bool exact_match = true;
TypeList class_types;
uint32_t num_matches = target->GetImages().FindTypes (sc,
ConstString(class_name),
exact_match,
UINT32_MAX,
class_types);
lldb::TypeSP type_sp;
if (num_matches == 0)
{
if (log)
log->Printf("0x%16.16llx: is not dynamic\n", original_ptr);
return false;
}
if (num_matches == 1)
{
type_sp = class_types.GetTypeAtIndex(0);
if (log)
log->Printf ("0x%16.16llx: static-type = '%s' has dynamic type: uid={0x%llx}, type-name='%s'\n",
original_ptr,
in_value.GetTypeName().AsCString(),
type_sp->GetID(),
type_sp->GetName().GetCString());
class_type_or_name.SetTypeSP(class_types.GetTypeAtIndex(0));
}
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%16.16llx: static-type = '%s' has multiple matching dynamic types: uid={0x%llx}, 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->GetClangFullType()))
{
if (log)
log->Printf ("0x%16.16llx: static-type = '%s' has multiple matching dynamic types, picking this one: uid={0x%llx}, type-name='%s'\n",
original_ptr,
in_value.GetTypeName().AsCString(),
type_sp->GetID(),
type_sp->GetName().GetCString());
class_type_or_name.SetTypeSP(type_sp);
break;
}
}
}
if (i == num_matches)
{
if (log)
log->Printf ("0x%16.16llx: static-type = '%s' has multiple matching dynamic types, didn't find a C++ match\n",
original_ptr,
in_value.GetTypeName().AsCString());
return false;
}
}
// 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)
{
clang::ASTContext *in_ast_ctx = in_value.GetClangAST ();
clang::ASTContext *this_ast_ctx = type_sp->GetClangAST ();
if (in_ast_ctx == this_ast_ctx)
{
if (ClangASTContext::AreTypesSame (in_ast_ctx,
in_value.GetClangType(),
type_sp->GetClangFullType()))
{
// 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 address.
Address offset_to_top_address = address_point_address;
int64_t slide = -2 * ((int64_t) target->GetArchitecture().GetAddressByteSize());
offset_to_top_address.Slide (slide);
Error error;
lldb::addr_t offset_to_top_location = offset_to_top_address.GetLoadAddress(target);
size_t bytes_read = process->ReadMemory (offset_to_top_location,
memory_buffer,
address_byte_size,
error);
if (!error.Success() || (bytes_read != address_byte_size))
{
return false;
}
offset_ptr = 0;
int64_t offset_to_top = data.GetMaxS64(&offset_ptr, process->GetAddressByteSize());
// 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 (!target->GetSectionLoadList().ResolveLoadAddress (dynamic_addr, dynamic_address))
{
dynamic_address.SetRawAddress(dynamic_addr);
}
return true;
}
}
}
}
}
}
return false;
}
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)
return new ItaniumABILanguageRuntime (process);
else
return NULL;
}
void
ItaniumABILanguageRuntime::Initialize()
{
PluginManager::RegisterPlugin (pluginName,
pluginDesc,
CreateInstance);
}
void
ItaniumABILanguageRuntime::Terminate()
{
PluginManager::UnregisterPlugin (CreateInstance);
}
//------------------------------------------------------------------
// PluginInterface protocol
//------------------------------------------------------------------
const char *
ItaniumABILanguageRuntime::GetPluginName()
{
return pluginName;
}
const char *
ItaniumABILanguageRuntime::GetShortPluginName()
{
return pluginShort;
}
uint32_t
ItaniumABILanguageRuntime::GetPluginVersion()
{
return 1;
}
static const char *exception_names[] = { "__cxa_begin_catch", "__cxa_throw", "__cxa_rethrow", "__cxa_allocate_exception"};
static const int num_throw_names = 3;
static const int num_expression_throw_names = 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)
{
BreakpointResolverSP resolver_sp;
static const int total_expressions = sizeof (exception_names)/sizeof (char *);
// 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.
uint32_t num_expressions;
if (catch_bp && throw_bp)
{
if (for_expressions)
num_expressions = total_expressions;
else
num_expressions = total_expressions - num_expression_throw_names;
resolver_sp.reset (new BreakpointResolverName (bkpt,
exception_names,
num_expressions,
eFunctionNameTypeBase,
eLazyBoolNo));
}
else if (throw_bp)
{
if (for_expressions)
num_expressions = num_throw_names - num_expression_throw_names;
else
num_expressions = num_throw_names;
resolver_sp.reset (new BreakpointResolverName (bkpt,
exception_names + 1,
num_expressions,
eFunctionNameTypeBase,
eLazyBoolNo));
}
else if (catch_bp)
resolver_sp.reset (new BreakpointResolverName (bkpt,
exception_names,
total_expressions - num_throw_names,
eFunctionNameTypeBase,
eLazyBoolNo));
return resolver_sp;
}
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)
{
Target &target = m_process->GetTarget();
BreakpointResolverSP exception_resolver_sp = CreateExceptionResolver (NULL, catch_bp, throw_bp, for_expressions);
SearchFilterSP filter_sp = target.GetSearchFilterForModule(NULL);
m_cxx_exception_bp_sp = target.CreateBreakpoint (filter_sp, exception_resolver_sp, is_internal);
}
else
m_cxx_exception_bp_sp->SetEnabled (true);
}
void
ItaniumABILanguageRuntime::ClearExceptionBreakpoints ()
{
if (!m_process)
return;
if (m_cxx_exception_bp_sp.get())
{
m_cxx_exception_bp_sp->SetEnabled (false);
}
}
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());
}
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