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llvm-project/lldb/source/Plugins/DynamicLoader/Hexagon-DYLD/DynamicLoaderHexagonDYLD.cpp

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//===-- DynamicLoaderHexagon.h ----------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// C Includes
// C++ Includes
// Other libraries and framework includes
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleSpec.h"
#include "lldb/Core/Section.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlanRunToAddress.h"
#include "lldb/Breakpoint/BreakpointLocation.h"
#include "DynamicLoaderHexagonDYLD.h"
using namespace lldb;
using namespace lldb_private;
// Aidan 21/05/2014
//
// Notes about hexagon dynamic loading:
//
// When we connect to a target we find the dyld breakpoint address. We put a
// breakpoint there with a callback 'RendezvousBreakpointHit()'.
//
// It is possible to find the dyld structure address from the ELF symbol table,
// but in the case of the simulator it has not been initialized before the
// target calls dlinit().
//
// We can only safely parse the dyld structure after we hit the dyld breakpoint
// since at that time we know dlinit() must have been called.
//
// Find the load address of a symbol
static lldb::addr_t findSymbolAddress( Process *proc, ConstString findName )
{
assert( proc != nullptr );
ModuleSP module = proc->GetTarget().GetExecutableModule();
assert( module.get() != nullptr );
ObjectFile *exe = module->GetObjectFile();
assert( exe != nullptr );
lldb_private::Symtab *symtab = exe->GetSymtab( );
assert( symtab != nullptr );
for ( size_t i = 0; i < symtab->GetNumSymbols( ); i++ )
{
const Symbol* sym = symtab->SymbolAtIndex( i );
assert( sym != nullptr );
const ConstString &symName = sym->GetName( );
if ( ConstString::Compare( findName, symName ) == 0 )
{
Address addr = sym->GetAddress( );
return addr.GetLoadAddress( & proc->GetTarget() );
}
}
return LLDB_INVALID_ADDRESS;
}
void
DynamicLoaderHexagonDYLD::Initialize()
{
PluginManager::RegisterPlugin(GetPluginNameStatic(),
GetPluginDescriptionStatic(),
CreateInstance);
}
void
DynamicLoaderHexagonDYLD::Terminate()
{
}
lldb_private::ConstString
DynamicLoaderHexagonDYLD::GetPluginName()
{
return GetPluginNameStatic();
}
lldb_private::ConstString
DynamicLoaderHexagonDYLD::GetPluginNameStatic()
{
static ConstString g_name("hexagon-dyld");
return g_name;
}
const char *
DynamicLoaderHexagonDYLD::GetPluginDescriptionStatic()
{
return "Dynamic loader plug-in that watches for shared library "
"loads/unloads in Hexagon processes.";
}
void
DynamicLoaderHexagonDYLD::GetPluginCommandHelp(const char *command, Stream *strm)
{
}
uint32_t
DynamicLoaderHexagonDYLD::GetPluginVersion()
{
return 1;
}
DynamicLoader *
DynamicLoaderHexagonDYLD::CreateInstance(Process *process, bool force)
{
bool create = force;
if (!create)
{
const llvm::Triple &triple_ref = process->GetTarget().GetArchitecture().GetTriple();
if (triple_ref.getArch() == llvm::Triple::hexagon)
create = true;
}
if (create)
return new DynamicLoaderHexagonDYLD(process);
return NULL;
}
DynamicLoaderHexagonDYLD::DynamicLoaderHexagonDYLD(Process *process)
: DynamicLoader(process)
, m_rendezvous (process)
, m_load_offset(LLDB_INVALID_ADDRESS)
, m_entry_point(LLDB_INVALID_ADDRESS)
, m_dyld_bid (LLDB_INVALID_BREAK_ID)
{
}
DynamicLoaderHexagonDYLD::~DynamicLoaderHexagonDYLD()
{
if (m_dyld_bid != LLDB_INVALID_BREAK_ID)
{
m_process->GetTarget().RemoveBreakpointByID (m_dyld_bid);
m_dyld_bid = LLDB_INVALID_BREAK_ID;
}
}
void
DynamicLoaderHexagonDYLD::DidAttach()
{
ModuleSP executable;
addr_t load_offset;
executable = GetTargetExecutable();
// Find the difference between the desired load address in the elf file
// and the real load address in memory
load_offset = ComputeLoadOffset();
// Check that there is a valid executable
if ( executable.get( ) == nullptr )
return;
// Disable JIT for hexagon targets because its not supported
m_process->SetCanJIT(false);
// Add the current executable to the module list
ModuleList module_list;
module_list.Append(executable);
// Map the loaded sections of this executable
if ( load_offset != LLDB_INVALID_ADDRESS )
UpdateLoadedSections(executable, LLDB_INVALID_ADDRESS, load_offset);
// AD: confirm this?
// Load into LLDB all of the currently loaded executables in the stub
LoadAllCurrentModules();
// AD: confirm this?
// Callback for the target to give it the loaded module list
m_process->GetTarget().ModulesDidLoad(module_list);
// Try to set a breakpoint at the rendezvous breakpoint.
// DidLaunch uses ProbeEntry() instead. That sets a breakpoint,
// at the dyld breakpoint address, with a callback so that when hit,
// the dyld structure can be parsed.
if (! SetRendezvousBreakpoint() )
{
// fail
}
}
void
DynamicLoaderHexagonDYLD::DidLaunch()
{
}
/// Checks to see if the target module has changed, updates the target
/// accordingly and returns the target executable module.
ModuleSP
DynamicLoaderHexagonDYLD::GetTargetExecutable()
{
Target &target = m_process->GetTarget();
ModuleSP executable = target.GetExecutableModule();
// There is no executable
if (! executable.get())
return executable;
// The target executable file does not exits
if (! executable->GetFileSpec().Exists())
return executable;
// Prep module for loading
ModuleSpec module_spec(executable->GetFileSpec(), executable->GetArchitecture());
ModuleSP module_sp (new Module (module_spec));
// Check if the executable has changed and set it to the target executable if they differ.
if (module_sp.get() && module_sp->GetUUID().IsValid() && executable->GetUUID().IsValid())
{
// if the executable has changed ??
if (module_sp->GetUUID() != executable->GetUUID())
executable.reset();
}
else if (executable->FileHasChanged())
executable.reset();
if ( executable.get( ) )
return executable;
// TODO: What case is this code used?
executable = target.GetSharedModule(module_spec);
if (executable.get() != target.GetExecutableModulePointer())
{
// Don't load dependent images since we are in dyld where we will know
// and find out about all images that are loaded
const bool get_dependent_images = false;
target.SetExecutableModule(executable, get_dependent_images);
}
return executable;
}
Error
DynamicLoaderHexagonDYLD::ExecutePluginCommand(Args &command, Stream *strm)
{
return Error();
}
Log *
DynamicLoaderHexagonDYLD::EnablePluginLogging(Stream *strm, Args &command)
{
return NULL;
}
//AD: Needs to be updated?
Error
DynamicLoaderHexagonDYLD::CanLoadImage()
{
return Error();
}
void
DynamicLoaderHexagonDYLD::UpdateLoadedSections(ModuleSP module, addr_t link_map_addr, addr_t base_addr)
{
Target &target = m_process->GetTarget();
const SectionList *sections = GetSectionListFromModule(module);
assert(sections && "SectionList missing from loaded module.");
m_loaded_modules[module] = link_map_addr;
const size_t num_sections = sections->GetSize();
for (unsigned i = 0; i < num_sections; ++i)
{
SectionSP section_sp (sections->GetSectionAtIndex(i));
lldb::addr_t new_load_addr = section_sp->GetFileAddress() + base_addr;
// AD: 02/05/14
// since our memory map starts from address 0, we must not ignore
// sections that load to address 0. This violates the reference
// ELF spec, however is used for Hexagon.
// If the file address of the section is zero then this is not an
// allocatable/loadable section (property of ELF sh_addr). Skip it.
// if (new_load_addr == base_addr)
// continue;
target.SetSectionLoadAddress(section_sp, new_load_addr);
}
}
/// Removes the loaded sections from the target in @p module.
///
/// @param module The module to traverse.
void
DynamicLoaderHexagonDYLD::UnloadSections(const ModuleSP module)
{
Target &target = m_process->GetTarget();
const SectionList *sections = GetSectionListFromModule(module);
assert(sections && "SectionList missing from unloaded module.");
m_loaded_modules.erase(module);
const size_t num_sections = sections->GetSize();
for (size_t i = 0; i < num_sections; ++i)
{
SectionSP section_sp (sections->GetSectionAtIndex(i));
target.SetSectionUnloaded(section_sp);
}
}
// Place a breakpoint on <_rtld_debug_state>
bool
DynamicLoaderHexagonDYLD::SetRendezvousBreakpoint()
{
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
// This is the original code, which want to look in the rendezvous structure
// to find the breakpoint address. Its backwards for us, since we can easily
// find the breakpoint address, since it is exported in our executable.
// We however know that we cant read the Rendezvous structure until we have hit
// the breakpoint once.
const ConstString dyldBpName( "_rtld_debug_state" );
addr_t break_addr = findSymbolAddress( m_process, dyldBpName );
Target &target = m_process->GetTarget();
// Do not try to set the breakpoint if we don't know where to put it
if ( break_addr == LLDB_INVALID_ADDRESS )
{
if ( log )
log->Printf( "Unable to locate _rtld_debug_state breakpoint address" );
return false;
}
// Save the address of the rendezvous structure
m_rendezvous.SetBreakAddress( break_addr );
// If we haven't set the breakpoint before then set it
if (m_dyld_bid == LLDB_INVALID_BREAK_ID)
{
Breakpoint *dyld_break = target.CreateBreakpoint (break_addr, true, false).get();
dyld_break->SetCallback(RendezvousBreakpointHit, this, true);
dyld_break->SetBreakpointKind ("shared-library-event");
m_dyld_bid = dyld_break->GetID();
// Make sure our breakpoint is at the right address.
assert
(
target.GetBreakpointByID(m_dyld_bid)->
FindLocationByAddress(break_addr)->
GetBreakpoint().GetID()
== m_dyld_bid
);
if ( log && dyld_break == nullptr )
log->Printf( "Failed to create _rtld_debug_state breakpoint" );
// check we have successfully set bp
return (dyld_break != nullptr);
}
else
// rendezvous already set
return true;
}
// We have just hit our breakpoint at <_rtld_debug_state>
bool
DynamicLoaderHexagonDYLD::RendezvousBreakpointHit(void *baton,
StoppointCallbackContext *context,
user_id_t break_id,
user_id_t break_loc_id)
{
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
if ( log )
log->Printf( "Rendezvous breakpoint hit!" );
DynamicLoaderHexagonDYLD* dyld_instance = nullptr;
dyld_instance = static_cast<DynamicLoaderHexagonDYLD*>(baton);
// if the dyld_instance is still not valid then
// try to locate it on the symbol table
if ( !dyld_instance->m_rendezvous.IsValid( ) )
{
Process *proc = dyld_instance->m_process;
const ConstString dyldStructName( "_rtld_debug" );
addr_t structAddr = findSymbolAddress( proc, dyldStructName );
if ( structAddr != LLDB_INVALID_ADDRESS )
{
dyld_instance->m_rendezvous.SetRendezvousAddress( structAddr );
if ( log )
log->Printf( "Found _rtld_debug structure @ 0x%08lx", structAddr );
}
else
{
if ( log )
log->Printf( "Unable to resolve the _rtld_debug structure" );
}
}
dyld_instance->RefreshModules();
// Return true to stop the target, false to just let the target run.
return dyld_instance->GetStopWhenImagesChange();
}
/// Helper method for RendezvousBreakpointHit. Updates LLDB's current set
/// of loaded modules.
void
DynamicLoaderHexagonDYLD::RefreshModules()
{
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
if (!m_rendezvous.Resolve())
return;
HexagonDYLDRendezvous::iterator I;
HexagonDYLDRendezvous::iterator E;
ModuleList &loaded_modules = m_process->GetTarget().GetImages();
if (m_rendezvous.ModulesDidLoad())
{
ModuleList new_modules;
E = m_rendezvous.loaded_end();
for (I = m_rendezvous.loaded_begin(); I != E; ++I)
{
FileSpec file(I->path.c_str(), true);
ModuleSP module_sp = LoadModuleAtAddress(file, I->link_addr, I->base_addr);
if (module_sp.get())
{
loaded_modules.AppendIfNeeded( module_sp );
new_modules.Append(module_sp);
}
if (log)
{
log->Printf( "Target is loading '%s'", I->path.c_str() );
if (! module_sp.get() )
log->Printf( "LLDB failed to load '%s'", I->path.c_str() );
else
log->Printf( "LLDB successfully loaded '%s'", I->path.c_str() );
}
}
m_process->GetTarget().ModulesDidLoad(new_modules);
}
if (m_rendezvous.ModulesDidUnload())
{
ModuleList old_modules;
E = m_rendezvous.unloaded_end();
for (I = m_rendezvous.unloaded_begin(); I != E; ++I)
{
FileSpec file(I->path.c_str(), true);
ModuleSpec module_spec(file);
ModuleSP module_sp = loaded_modules.FindFirstModule (module_spec);
if (module_sp.get())
{
old_modules.Append(module_sp);
UnloadSections(module_sp);
}
if (log)
log->Printf( "Target is unloading '%s'", I->path.c_str() );
}
loaded_modules.Remove(old_modules);
m_process->GetTarget().ModulesDidUnload(old_modules, false);
}
}
//AD: This is very different to the Static Loader code.
// It may be wise to look over this and its relation to stack
// unwinding.
ThreadPlanSP
DynamicLoaderHexagonDYLD::GetStepThroughTrampolinePlan(Thread &thread, bool stop)
{
ThreadPlanSP thread_plan_sp;
StackFrame *frame = thread.GetStackFrameAtIndex(0).get();
const SymbolContext &context = frame->GetSymbolContext(eSymbolContextSymbol);
Symbol *sym = context.symbol;
if (sym == NULL || !sym->IsTrampoline())
return thread_plan_sp;
const ConstString &sym_name = sym->GetMangled().GetName(Mangled::ePreferMangled);
if (!sym_name)
return thread_plan_sp;
SymbolContextList target_symbols;
Target &target = thread.GetProcess()->GetTarget();
const ModuleList &images = target.GetImages();
images.FindSymbolsWithNameAndType(sym_name, eSymbolTypeCode, target_symbols);
size_t num_targets = target_symbols.GetSize();
if (!num_targets)
return thread_plan_sp;
typedef std::vector<lldb::addr_t> AddressVector;
AddressVector addrs;
for (size_t i = 0; i < num_targets; ++i)
{
SymbolContext context;
AddressRange range;
if (target_symbols.GetContextAtIndex(i, context))
{
context.GetAddressRange(eSymbolContextEverything, 0, false, range);
lldb::addr_t addr = range.GetBaseAddress().GetLoadAddress(&target);
if (addr != LLDB_INVALID_ADDRESS)
addrs.push_back(addr);
}
}
if (addrs.size() > 0)
{
AddressVector::iterator start = addrs.begin();
AddressVector::iterator end = addrs.end();
std::sort(start, end);
addrs.erase(std::unique(start, end), end);
thread_plan_sp.reset(new ThreadPlanRunToAddress(thread, addrs, stop));
}
return thread_plan_sp;
}
/// Helper for the entry breakpoint callback. Resolves the load addresses
/// of all dependent modules.
void
DynamicLoaderHexagonDYLD::LoadAllCurrentModules()
{
HexagonDYLDRendezvous::iterator I;
HexagonDYLDRendezvous::iterator E;
ModuleList module_list;
if (!m_rendezvous.Resolve())
{
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
if (log)
log->Printf("DynamicLoaderHexagonDYLD::%s unable to resolve rendezvous address", __FUNCTION__);
return;
}
// The rendezvous class doesn't enumerate the main module, so track
// that ourselves here.
ModuleSP executable = GetTargetExecutable();
m_loaded_modules[executable] = m_rendezvous.GetLinkMapAddress();
for (I = m_rendezvous.begin(), E = m_rendezvous.end(); I != E; ++I)
{
const char *module_path = I->path.c_str();
FileSpec file(module_path, false);
ModuleSP module_sp = LoadModuleAtAddress(file, I->link_addr, I->base_addr);
if (module_sp.get())
{
module_list.Append(module_sp);
}
else
{
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
if (log)
log->Printf("DynamicLoaderHexagonDYLD::%s failed loading module %s at 0x%" PRIx64,
__FUNCTION__, module_path, I->base_addr);
}
}
m_process->GetTarget().ModulesDidLoad(module_list);
}
/// Helper for the entry breakpoint callback. Resolves the load addresses
/// of all dependent modules.
ModuleSP
DynamicLoaderHexagonDYLD::LoadModuleAtAddress(const FileSpec &file, addr_t link_map_addr, addr_t base_addr)
{
Target &target = m_process->GetTarget();
ModuleList &modules = target.GetImages();
ModuleSP module_sp;
ModuleSpec module_spec (file, target.GetArchitecture());
// check if module is currently loaded
if ((module_sp = modules.FindFirstModule (module_spec)))
{
UpdateLoadedSections(module_sp, link_map_addr, base_addr);
}
// try to load this module from disk
else if ((module_sp = target.GetSharedModule(module_spec)))
{
UpdateLoadedSections(module_sp, link_map_addr, base_addr);
}
return module_sp;
}
/// Computes a value for m_load_offset returning the computed address on
/// success and LLDB_INVALID_ADDRESS on failure.
addr_t
DynamicLoaderHexagonDYLD::ComputeLoadOffset()
{
// Here we could send a GDB packet to know the load offset
//
// send: $qOffsets#4b
// get: Text=0;Data=0;Bss=0
//
// Currently qOffsets is not supported by pluginProcessGDBRemote
//
return 0;
}
// Here we must try to read the entry point directly from
// the elf header. This is possible if the process is not
// relocatable or dynamically linked.
//
// an alternative is to look at the PC if we can be sure
// that we have connected when the process is at the entry point.
// I dont think that is reliable for us.
addr_t
DynamicLoaderHexagonDYLD::GetEntryPoint()
{
if (m_entry_point != LLDB_INVALID_ADDRESS)
return m_entry_point;
// check we have a valid process
if ( m_process == nullptr )
return LLDB_INVALID_ADDRESS;
// Get the current executable module
Module & module = *( m_process->GetTarget( ).GetExecutableModule( ).get( ) );
// Get the object file (elf file) for this module
lldb_private::ObjectFile &object = *( module.GetObjectFile( ) );
// Check if the file is executable (ie, not shared object or relocatable)
if ( object.IsExecutable() )
{
// Get the entry point address for this object
lldb_private::Address entry = object.GetEntryPointAddress( );
// Return the entry point address
return entry.GetFileAddress( );
}
// No idea so back out
return LLDB_INVALID_ADDRESS;
}
const SectionList *
DynamicLoaderHexagonDYLD::GetSectionListFromModule(const ModuleSP module) const
{
SectionList *sections = nullptr;
if (module.get())
{
ObjectFile *obj_file = module->GetObjectFile();
if (obj_file)
{
sections = obj_file->GetSectionList();
}
}
return sections;
}
static int ReadInt(Process *process, addr_t addr)
{
Error error;
int value = (int)process->ReadUnsignedIntegerFromMemory(addr, sizeof(uint32_t), 0, error);
if (error.Fail())
return -1;
else
return value;
}
lldb::addr_t
DynamicLoaderHexagonDYLD::GetThreadLocalData (const lldb::ModuleSP module, const lldb::ThreadSP thread)
{
auto it = m_loaded_modules.find (module);
if (it == m_loaded_modules.end())
return LLDB_INVALID_ADDRESS;
addr_t link_map = it->second;
if (link_map == LLDB_INVALID_ADDRESS)
return LLDB_INVALID_ADDRESS;
const HexagonDYLDRendezvous::ThreadInfo &metadata = m_rendezvous.GetThreadInfo();
if (!metadata.valid)
return LLDB_INVALID_ADDRESS;
// Get the thread pointer.
addr_t tp = thread->GetThreadPointer ();
if (tp == LLDB_INVALID_ADDRESS)
return LLDB_INVALID_ADDRESS;
// Find the module's modid.
int modid = ReadInt (m_process, link_map + metadata.modid_offset);
if (modid == -1)
return LLDB_INVALID_ADDRESS;
// Lookup the DTV stucture for this thread.
addr_t dtv_ptr = tp + metadata.dtv_offset;
addr_t dtv = ReadPointer (dtv_ptr);
if (dtv == LLDB_INVALID_ADDRESS)
return LLDB_INVALID_ADDRESS;
// Find the TLS block for this module.
addr_t dtv_slot = dtv + metadata.dtv_slot_size*modid;
addr_t tls_block = ReadPointer (dtv_slot + metadata.tls_offset);
Module *mod = module.get();
Log *log(GetLogIfAnyCategoriesSet(LIBLLDB_LOG_DYNAMIC_LOADER));
if (log)
log->Printf("DynamicLoaderHexagonDYLD::Performed TLS lookup: "
"module=%s, link_map=0x%" PRIx64 ", tp=0x%" PRIx64 ", modid=%i, tls_block=0x%" PRIx64,
mod->GetObjectName().AsCString(""), link_map, tp, modid, tls_block);
return tls_block;
}
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