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llvm-project/lldb/source/Expression/ClangFunction.cpp

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//===-- ClangFunction.cpp ---------------------------------------*- 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 "clang/AST/ASTContext.h"
#include "clang/AST/RecordLayout.h"
#include "clang/CodeGen/CodeGenAction.h"
#include "clang/CodeGen/ModuleBuilder.h"
#include "clang/Frontend/CompilerInstance.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/Module.h"
// Project includes
#include "lldb/Expression/ASTStructExtractor.h"
#include "lldb/Expression/ClangExpressionParser.h"
#include "lldb/Expression/ClangFunction.h"
#include "lldb/Symbol/Type.h"
#include "lldb/Core/DataExtractor.h"
#include "lldb/Core/State.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Core/ValueObjectList.h"
#include "lldb/Interpreter/CommandReturnObject.h"
#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Symbol/Function.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/StopInfo.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlan.h"
#include "lldb/Target/ThreadPlanCallFunction.h"
#include "lldb/Core/Log.h"
using namespace lldb_private;
//----------------------------------------------------------------------
// ClangFunction constructor
//----------------------------------------------------------------------
ClangFunction::ClangFunction
(
const char *target_triple,
ClangASTContext *ast_context,
void *return_qualtype,
const Address& functionAddress,
const ValueList &arg_value_list
) :
m_target_triple (target_triple),
m_function_ptr (NULL),
m_function_addr (functionAddress),
m_function_return_qual_type(return_qualtype),
m_clang_ast_context (ast_context),
m_wrapper_function_name ("__lldb_caller_function"),
m_wrapper_struct_name ("__lldb_caller_struct"),
m_wrapper_function_addr (),
m_wrapper_args_addrs (),
m_arg_values (arg_value_list),
m_compiled (false),
m_JITted (false)
{
}
ClangFunction::ClangFunction
(
const char *target_triple,
Function &function,
ClangASTContext *ast_context,
const ValueList &arg_value_list
) :
m_target_triple (target_triple),
m_function_ptr (&function),
m_function_addr (),
m_function_return_qual_type (),
m_clang_ast_context (ast_context),
m_wrapper_function_name ("__lldb_function_caller"),
m_wrapper_struct_name ("__lldb_caller_struct"),
m_wrapper_function_addr (),
m_wrapper_args_addrs (),
m_arg_values (arg_value_list),
m_compiled (false),
m_JITted (false)
{
m_function_addr = m_function_ptr->GetAddressRange().GetBaseAddress();
m_function_return_qual_type = m_function_ptr->GetReturnType().GetClangType();
}
//----------------------------------------------------------------------
// Destructor
//----------------------------------------------------------------------
ClangFunction::~ClangFunction()
{
}
unsigned
ClangFunction::CompileFunction (Stream &errors)
{
if (m_compiled)
return 0;
// FIXME: How does clang tell us there's no return value? We need to handle that case.
unsigned num_errors = 0;
std::string return_type_str = ClangASTContext::GetTypeName(m_function_return_qual_type);
// Cons up the function we're going to wrap our call in, then compile it...
// We declare the function "extern "C"" because the compiler might be in C++
// mode which would mangle the name and then we couldn't find it again...
m_wrapper_function_text.clear();
m_wrapper_function_text.append ("extern \"C\" void ");
m_wrapper_function_text.append (m_wrapper_function_name);
m_wrapper_function_text.append (" (void *input)\n{\n struct ");
m_wrapper_function_text.append (m_wrapper_struct_name);
m_wrapper_function_text.append (" \n {\n");
m_wrapper_function_text.append (" ");
m_wrapper_function_text.append (return_type_str);
m_wrapper_function_text.append (" (*fn_ptr) (");
// Get the number of arguments. If we have a function type and it is prototyped,
// trust that, otherwise use the values we were given.
// FIXME: This will need to be extended to handle Variadic functions. We'll need
// to pull the defined arguments out of the function, then add the types from the
// arguments list for the variable arguments.
uint32_t num_args = UINT32_MAX;
bool trust_function = false;
// GetArgumentCount returns -1 for an unprototyped function.
if (m_function_ptr)
{
int num_func_args = m_function_ptr->GetArgumentCount();
if (num_func_args >= 0)
trust_function = true;
else
num_args = num_func_args;
}
if (num_args == UINT32_MAX)
num_args = m_arg_values.GetSize();
std::string args_buffer; // This one stores the definition of all the args in "struct caller".
std::string args_list_buffer; // This one stores the argument list called from the structure.
for (size_t i = 0; i < num_args; i++)
{
const char *type_string;
std::string type_stdstr;
if (trust_function)
{
type_string = m_function_ptr->GetArgumentTypeAtIndex(i).GetName().AsCString();
}
else
{
Value *arg_value = m_arg_values.GetValueAtIndex(i);
void *clang_qual_type = arg_value->GetClangType ();
if (clang_qual_type != NULL)
{
type_stdstr = ClangASTContext::GetTypeName(clang_qual_type);
type_string = type_stdstr.c_str();
}
else
{
errors.Printf("Could not determine type of input value %d.", i);
return 1;
}
}
m_wrapper_function_text.append (type_string);
if (i < num_args - 1)
m_wrapper_function_text.append (", ");
char arg_buf[32];
args_buffer.append (" ");
args_buffer.append (type_string);
snprintf(arg_buf, 31, "arg_%zd", i);
args_buffer.push_back (' ');
args_buffer.append (arg_buf);
args_buffer.append (";\n");
args_list_buffer.append ("__lldb_fn_data->");
args_list_buffer.append (arg_buf);
if (i < num_args - 1)
args_list_buffer.append (", ");
}
m_wrapper_function_text.append (");\n"); // Close off the function calling prototype.
m_wrapper_function_text.append (args_buffer);
m_wrapper_function_text.append (" ");
m_wrapper_function_text.append (return_type_str);
m_wrapper_function_text.append (" return_value;");
m_wrapper_function_text.append ("\n };\n struct ");
m_wrapper_function_text.append (m_wrapper_struct_name);
m_wrapper_function_text.append ("* __lldb_fn_data = (struct ");
m_wrapper_function_text.append (m_wrapper_struct_name);
m_wrapper_function_text.append (" *) input;\n");
m_wrapper_function_text.append (" __lldb_fn_data->return_value = __lldb_fn_data->fn_ptr (");
m_wrapper_function_text.append (args_list_buffer);
m_wrapper_function_text.append (");\n}\n");
lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
if (log)
log->Printf ("Expression: \n\n%s\n\n", m_wrapper_function_text.c_str());
// Okay, now compile this expression
m_parser.reset(new ClangExpressionParser(m_target_triple.c_str(), *this));
num_errors = m_parser->Parse (errors);
m_compiled = (num_errors == 0);
if (!m_compiled)
return num_errors;
return num_errors;
}
bool
ClangFunction::WriteFunctionWrapper (ExecutionContext &exe_ctx, Stream &errors)
{
Process *process = exe_ctx.process;
if (!process)
return false;
if (!m_compiled)
return false;
if (m_JITted)
return true;
lldb::addr_t wrapper_function_end;
Error jit_error = m_parser->MakeJIT(m_wrapper_function_addr, wrapper_function_end, exe_ctx);
if (!jit_error.Success())
return false;
return true;
}
bool
ClangFunction::WriteFunctionArguments (ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref, Stream &errors)
{
return WriteFunctionArguments(exe_ctx, args_addr_ref, m_function_addr, m_arg_values, errors);
}
// FIXME: Assure that the ValueList we were passed in is consistent with the one that defined this function.
bool
ClangFunction::WriteFunctionArguments (ExecutionContext &exe_ctx,
lldb::addr_t &args_addr_ref,
Address function_address,
ValueList &arg_values,
Stream &errors)
{
// All the information to reconstruct the struct is provided by the
// StructExtractor.
if (!m_struct_valid)
{
errors.Printf("Argument information was not correctly parsed, so the function cannot be called.");
return false;
}
Error error;
using namespace clang;
ExecutionResults return_value = eExecutionSetupError;
Process *process = exe_ctx.process;
if (process == NULL)
return return_value;
if (args_addr_ref == LLDB_INVALID_ADDRESS)
{
args_addr_ref = process->AllocateMemory(m_struct_size, lldb::ePermissionsReadable|lldb::ePermissionsWritable, error);
if (args_addr_ref == LLDB_INVALID_ADDRESS)
return false;
m_wrapper_args_addrs.push_back (args_addr_ref);
}
else
{
// Make sure this is an address that we've already handed out.
if (find (m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(), args_addr_ref) == m_wrapper_args_addrs.end())
{
return false;
}
}
// FIXME: This is fake, and just assumes that it matches that architecture.
// Make a data extractor and put the address into the right byte order & size.
uint64_t fun_addr = function_address.GetLoadAddress(exe_ctx.target);
int first_offset = m_member_offsets[0];
process->WriteMemory(args_addr_ref + first_offset, &fun_addr, 8, error);
// FIXME: We will need to extend this for Variadic functions.
Error value_error;
size_t num_args = arg_values.GetSize();
if (num_args != m_arg_values.GetSize())
{
errors.Printf ("Wrong number of arguments - was: %d should be: %d", num_args, m_arg_values.GetSize());
return false;
}
for (size_t i = 0; i < num_args; i++)
{
// FIXME: We should sanity check sizes.
int offset = m_member_offsets[i+1]; // Clang sizes are in bytes.
Value *arg_value = arg_values.GetValueAtIndex(i);
// FIXME: For now just do scalars:
// Special case: if it's a pointer, don't do anything (the ABI supports passing cstrings)
if (arg_value->GetValueType() == Value::eValueTypeHostAddress &&
arg_value->GetContextType() == Value::eContextTypeClangType &&
ClangASTContext::IsPointerType(arg_value->GetClangType()))
continue;
const Scalar &arg_scalar = arg_value->ResolveValue(&exe_ctx, m_clang_ast_context->getASTContext());
int byte_size = arg_scalar.GetByteSize();
std::vector<uint8_t> buffer;
buffer.resize(byte_size);
DataExtractor value_data;
arg_scalar.GetData (value_data);
value_data.ExtractBytes(0, byte_size, process->GetByteOrder(), &buffer.front());
process->WriteMemory(args_addr_ref + offset, &buffer.front(), byte_size, error);
}
return true;
}
bool
ClangFunction::InsertFunction (ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref, Stream &errors)
{
using namespace clang;
if (CompileFunction(errors) != 0)
return false;
if (!WriteFunctionWrapper(exe_ctx, errors))
return false;
if (!WriteFunctionArguments(exe_ctx, args_addr_ref, errors))
return false;
lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
if (log)
log->Printf ("Call Address: 0x%llx Struct Address: 0x%llx.\n", m_wrapper_function_addr, args_addr_ref);
return true;
}
ThreadPlan *
ClangFunction::GetThreadPlanToCallFunction (ExecutionContext &exe_ctx,
lldb::addr_t func_addr,
lldb::addr_t &args_addr,
Stream &errors,
bool stop_others,
bool discard_on_error,
lldb::addr_t *this_arg)
{
// FIXME: Use the errors Stream for better error reporting.
Process *process = exe_ctx.process;
if (process == NULL)
{
errors.Printf("Can't call a function without a process.");
return NULL;
}
// Okay, now run the function:
Address wrapper_address (NULL, func_addr);
ThreadPlan *new_plan = new ThreadPlanCallFunction (*exe_ctx.thread,
wrapper_address,
args_addr,
stop_others,
discard_on_error,
this_arg);
return new_plan;
}
bool
ClangFunction::FetchFunctionResults (ExecutionContext &exe_ctx, lldb::addr_t args_addr, Value &ret_value)
{
// Read the return value - it is the last field in the struct:
// FIXME: How does clang tell us there's no return value? We need to handle that case.
std::vector<uint8_t> data_buffer;
data_buffer.resize(m_return_size);
Process *process = exe_ctx.process;
Error error;
size_t bytes_read = process->ReadMemory(args_addr + m_return_offset, &data_buffer.front(), m_return_size, error);
if (bytes_read == 0)
{
return false;
}
if (bytes_read < m_return_size)
return false;
DataExtractor data(&data_buffer.front(), m_return_size, process->GetByteOrder(), process->GetAddressByteSize());
// FIXME: Assuming an integer scalar for now:
uint32_t offset = 0;
uint64_t return_integer = data.GetMaxU64(&offset, m_return_size);
ret_value.SetContext (Value::eContextTypeClangType, m_function_return_qual_type);
ret_value.SetValueType(Value::eValueTypeScalar);
ret_value.GetScalar() = return_integer;
return true;
}
void
ClangFunction::DeallocateFunctionResults (ExecutionContext &exe_ctx, lldb::addr_t args_addr)
{
std::list<lldb::addr_t>::iterator pos;
pos = std::find(m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(), args_addr);
if (pos != m_wrapper_args_addrs.end())
m_wrapper_args_addrs.erase(pos);
exe_ctx.process->DeallocateMemory(args_addr);
}
ClangFunction::ExecutionResults
ClangFunction::ExecuteFunction(ExecutionContext &exe_ctx, Stream &errors, Value &results)
{
return ExecuteFunction (exe_ctx, errors, 1000, true, results);
}
ClangFunction::ExecutionResults
ClangFunction::ExecuteFunction(ExecutionContext &exe_ctx, Stream &errors, bool stop_others, Value &results)
{
const bool try_all_threads = false;
const bool discard_on_error = true;
return ExecuteFunction (exe_ctx, NULL, errors, stop_others, NULL, try_all_threads, discard_on_error, results);
}
ClangFunction::ExecutionResults
ClangFunction::ExecuteFunction(
ExecutionContext &exe_ctx,
Stream &errors,
uint32_t single_thread_timeout_usec,
bool try_all_threads,
Value &results)
{
const bool stop_others = true;
const bool discard_on_error = true;
return ExecuteFunction (exe_ctx, NULL, errors, stop_others, single_thread_timeout_usec,
try_all_threads, discard_on_error, results);
}
// This is the static function
ClangFunction::ExecutionResults
ClangFunction::ExecuteFunction (
ExecutionContext &exe_ctx,
lldb::addr_t function_address,
lldb::addr_t &void_arg,
bool stop_others,
bool try_all_threads,
bool discard_on_error,
uint32_t single_thread_timeout_usec,
Stream &errors,
lldb::addr_t *this_arg)
{
// Save this value for restoration of the execution context after we run
uint32_t tid = exe_ctx.thread->GetIndexID();
// N.B. Running the target may unset the currently selected thread and frame. We don't want to do that either,
// so we should arrange to reset them as well.
lldb::ThreadSP selected_thread_sp = exe_ctx.process->GetThreadList().GetSelectedThread();
lldb::StackFrameSP selected_frame_sp;
uint32_t selected_tid;
if (selected_thread_sp != NULL)
{
selected_tid = selected_thread_sp->GetIndexID();
selected_frame_sp = selected_thread_sp->GetSelectedFrame();
}
else
{
selected_tid = LLDB_INVALID_THREAD_ID;
}
ClangFunction::ExecutionResults return_value = eExecutionSetupError;
lldb::ThreadPlanSP call_plan_sp(ClangFunction::GetThreadPlanToCallFunction(exe_ctx, function_address, void_arg,
errors, stop_others, discard_on_error,
this_arg));
ThreadPlanCallFunction *call_plan_ptr = static_cast<ThreadPlanCallFunction *> (call_plan_sp.get());
if (call_plan_sp == NULL)
return eExecutionSetupError;
call_plan_sp->SetPrivate(true);
exe_ctx.thread->QueueThreadPlan(call_plan_sp, true);
Listener listener("ClangFunction temporary listener");
exe_ctx.process->HijackProcessEvents(&listener);
Error resume_error = exe_ctx.process->Resume ();
if (!resume_error.Success())
{
errors.Printf("Error resuming inferior: \"%s\".\n", resume_error.AsCString());
exe_ctx.process->RestoreProcessEvents();
return eExecutionSetupError;
}
// We need to call the function synchronously, so spin waiting for it to return.
// If we get interrupted while executing, we're going to lose our context, and
// won't be able to gather the result at this point.
// We set the timeout AFTER the resume, since the resume takes some time and we
// don't want to charge that to the timeout.
TimeValue* timeout_ptr = NULL;
TimeValue real_timeout;
if (single_thread_timeout_usec != 0)
{
real_timeout = TimeValue::Now();
real_timeout.OffsetWithMicroSeconds(single_thread_timeout_usec);
timeout_ptr = &real_timeout;
}
lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
while (1)
{
lldb::EventSP event_sp;
lldb::StateType stop_state = lldb::eStateInvalid;
// Now wait for the process to stop again:
bool got_event = listener.WaitForEvent (timeout_ptr, event_sp);
if (!got_event)
{
// Right now this is the only way to tell we've timed out...
// We should interrupt the process here...
// Not really sure what to do if Halt fails here...
if (log)
if (try_all_threads)
log->Printf ("Running function with timeout: %d timed out, trying with all threads enabled.",
single_thread_timeout_usec);
else
log->Printf ("Running function with timeout: %d timed out, abandoning execution.",
single_thread_timeout_usec);
if (exe_ctx.process->Halt().Success())
{
timeout_ptr = NULL;
if (log)
log->Printf ("Halt succeeded.");
// Between the time that we got the timeout and the time we halted, but target
// might have actually completed the plan. If so, we're done. Note, I call WFE here with a short
// timeout to
got_event = listener.WaitForEvent(NULL, event_sp);
if (got_event)
{
stop_state = Process::ProcessEventData::GetStateFromEvent(event_sp.get());
if (log)
{
log->Printf ("Stopped with event: %s", StateAsCString(stop_state));
if (stop_state == lldb::eStateStopped && Process::ProcessEventData::GetInterruptedFromEvent(event_sp.get()))
log->Printf (" Event was the Halt interruption event.");
}
if (exe_ctx.thread->IsThreadPlanDone (call_plan_sp.get()))
{
if (log)
log->Printf ("Even though we timed out, the call plan was done. Exiting wait loop.");
return_value = eExecutionCompleted;
break;
}
if (try_all_threads
&& (stop_state == lldb::eStateStopped && Process::ProcessEventData::GetInterruptedFromEvent (event_sp.get())))
{
call_plan_ptr->SetStopOthers (false);
if (log)
log->Printf ("About to resume.");
exe_ctx.process->Resume();
continue;
}
else
{
exe_ctx.process->RestoreProcessEvents ();
return eExecutionInterrupted;
}
}
}
}
stop_state = Process::ProcessEventData::GetStateFromEvent(event_sp.get());
if (log)
log->Printf("Got event: %s.", StateAsCString(stop_state));
if (stop_state == lldb::eStateRunning || stop_state == lldb::eStateStepping)
continue;
if (exe_ctx.thread->IsThreadPlanDone (call_plan_sp.get()))
{
return_value = eExecutionCompleted;
break;
}
else if (exe_ctx.thread->WasThreadPlanDiscarded (call_plan_sp.get()))
{
return_value = eExecutionDiscarded;
break;
}
else
{
if (log)
{
StreamString s;
event_sp->Dump (&s);
StreamString ts;
const char *event_explanation;
do
{
const Process::ProcessEventData *event_data = Process::ProcessEventData::GetEventDataFromEvent (event_sp.get());
if (!event_data)
{
event_explanation = "<no event data>";
break;
}
Process *process = event_data->GetProcessSP().get();
if (!process)
{
event_explanation = "<no process>";
break;
}
ThreadList &thread_list = process->GetThreadList();
uint32_t num_threads = thread_list.GetSize();
uint32_t thread_index;
ts.Printf("<%u threads> ", num_threads);
for (thread_index = 0;
thread_index < num_threads;
++thread_index)
{
Thread *thread = thread_list.GetThreadAtIndex(thread_index).get();
if (!thread)
{
ts.Printf("<?> ");
continue;
}
ts.Printf("<");
RegisterContext *register_context = thread->GetRegisterContext();
if (register_context)
ts.Printf("[ip 0x%llx] ", register_context->GetPC());
else
ts.Printf("[ip unknown] ");
lldb::StopInfoSP stop_info_sp = thread->GetStopInfo();
if (stop_info_sp)
{
const char *stop_desc = stop_info_sp->GetDescription();
if (stop_desc)
ts.PutCString (stop_desc);
}
ts.Printf(">");
}
event_explanation = ts.GetData();
} while (0);
if (log)
log->Printf("Execution interrupted: %s %s", s.GetData(), event_explanation);
}
if (discard_on_error && call_plan_sp)
{
exe_ctx.thread->DiscardThreadPlansUpToPlan (call_plan_sp);
}
return_value = eExecutionInterrupted;
break;
}
}
if (exe_ctx.process)
exe_ctx.process->RestoreProcessEvents ();
// Thread we ran the function in may have gone away because we ran the target
// Check that it's still there.
exe_ctx.thread = exe_ctx.process->GetThreadList().FindThreadByIndexID(tid, true).get();
if (exe_ctx.thread)
exe_ctx.frame = exe_ctx.thread->GetStackFrameAtIndex(0).get();
// Also restore the current process'es selected frame & thread, since this function calling may
// be done behind the user's back.
if (selected_tid != LLDB_INVALID_THREAD_ID)
{
if (exe_ctx.process->GetThreadList().SetSelectedThreadByIndexID (selected_tid))
{
// We were able to restore the selected thread, now restore the frame:
exe_ctx.process->GetThreadList().GetSelectedThread()->SetSelectedFrame(selected_frame_sp.get());
}
}
return return_value;
}
ClangFunction::ExecutionResults
ClangFunction::ExecuteFunction(
ExecutionContext &exe_ctx,
lldb::addr_t *args_addr_ptr,
Stream &errors,
bool stop_others,
uint32_t single_thread_timeout_usec,
bool try_all_threads,
bool discard_on_error,
Value &results)
{
using namespace clang;
ExecutionResults return_value = eExecutionSetupError;
lldb::addr_t args_addr;
if (args_addr_ptr != NULL)
args_addr = *args_addr_ptr;
else
args_addr = LLDB_INVALID_ADDRESS;
if (CompileFunction(errors) != 0)
return eExecutionSetupError;
if (args_addr == LLDB_INVALID_ADDRESS)
{
if (!InsertFunction(exe_ctx, args_addr, errors))
return eExecutionSetupError;
}
return_value = ClangFunction::ExecuteFunction(exe_ctx, m_wrapper_function_addr, args_addr, stop_others,
try_all_threads, discard_on_error, single_thread_timeout_usec, errors);
if (args_addr_ptr != NULL)
*args_addr_ptr = args_addr;
if (return_value != eExecutionCompleted)
return return_value;
FetchFunctionResults(exe_ctx, args_addr, results);
if (args_addr_ptr == NULL)
DeallocateFunctionResults(exe_ctx, args_addr);
return eExecutionCompleted;
}
clang::ASTConsumer *
ClangFunction::ASTTransformer (clang::ASTConsumer *passthrough)
{
return new ASTStructExtractor(passthrough, m_wrapper_struct_name.c_str(), *this);
}
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