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llvm-project/lldb/source/Expression/FunctionCaller.cpp
Jim Ingham b565e7f0c4 Don't try to create Expressions when the process is running. 
We generally prohibit this at a higher level - for instance requiring
the process to be stopped for "expr".  But when we trigger an expression
for internal purposes (e.g. to fetch types from the ObjC runtime) we weren't
checking the process state.  Now we explicitly check this at the very start
of the job so we don't get into bad states.

Differential Revision: https://reviews.llvm.org/D137684
2022-11-09 10:07:09 -08:00

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//===-- FunctionCaller.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/Expression/FunctionCaller.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Core/ValueObjectList.h"
#include "lldb/Expression/DiagnosticManager.h"
#include "lldb/Expression/IRExecutionUnit.h"
#include "lldb/Interpreter/CommandReturnObject.h"
#include "lldb/Symbol/Function.h"
#include "lldb/Symbol/Type.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "lldb/Target/ThreadPlan.h"
#include "lldb/Target/ThreadPlanCallFunction.h"
#include "lldb/Utility/DataExtractor.h"
#include "lldb/Utility/LLDBLog.h"
#include "lldb/Utility/Log.h"
#include "lldb/Utility/State.h"
using namespace lldb_private;
char FunctionCaller::ID;
// FunctionCaller constructor
FunctionCaller::FunctionCaller(ExecutionContextScope &exe_scope,
const CompilerType &return_type,
const Address &functionAddress,
const ValueList &arg_value_list,
const char *name)
: Expression(exe_scope), m_execution_unit_sp(), m_parser(),
m_jit_module_wp(), m_name(name ? name : "<unknown>"),
m_function_ptr(nullptr), m_function_addr(functionAddress),
m_function_return_type(return_type),
m_wrapper_function_name("__lldb_caller_function"),
m_wrapper_struct_name("__lldb_caller_struct"), m_wrapper_args_addrs(),
m_struct_valid(false), m_struct_size(0), m_return_size(0),
m_return_offset(0), m_arg_values(arg_value_list), m_compiled(false),
m_JITted(false) {
m_jit_process_wp = lldb::ProcessWP(exe_scope.CalculateProcess());
// Can't make a FunctionCaller without a process.
assert(m_jit_process_wp.lock());
}
// Destructor
FunctionCaller::~FunctionCaller() {
lldb::ProcessSP process_sp(m_jit_process_wp.lock());
if (process_sp) {
lldb::ModuleSP jit_module_sp(m_jit_module_wp.lock());
if (jit_module_sp)
process_sp->GetTarget().GetImages().Remove(jit_module_sp);
}
}
bool FunctionCaller::WriteFunctionWrapper(
ExecutionContext &exe_ctx, DiagnosticManager &diagnostic_manager) {
Process *process = exe_ctx.GetProcessPtr();
if (!process) {
diagnostic_manager.Printf(eDiagnosticSeverityError, "no process.");
return false;
}
lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
if (process != jit_process_sp.get()) {
diagnostic_manager.Printf(eDiagnosticSeverityError,
"process does not match the stored process.");
return false;
}
if (process->GetState() != lldb::eStateStopped) {
diagnostic_manager.Printf(eDiagnosticSeverityError,
"process is not stopped");
return false;
}
if (!m_compiled) {
diagnostic_manager.Printf(eDiagnosticSeverityError,
"function not compiled");
return false;
}
if (m_JITted)
return true;
bool can_interpret = false; // should stay that way
Status jit_error(m_parser->PrepareForExecution(
m_jit_start_addr, m_jit_end_addr, m_execution_unit_sp, exe_ctx,
can_interpret, eExecutionPolicyAlways));
if (!jit_error.Success()) {
diagnostic_manager.Printf(eDiagnosticSeverityError,
"Error in PrepareForExecution: %s.",
jit_error.AsCString());
return false;
}
if (m_parser->GetGenerateDebugInfo()) {
lldb::ModuleSP jit_module_sp(m_execution_unit_sp->GetJITModule());
if (jit_module_sp) {
ConstString const_func_name(FunctionName());
FileSpec jit_file;
jit_file.SetFilename(const_func_name);
jit_module_sp->SetFileSpecAndObjectName(jit_file, ConstString());
m_jit_module_wp = jit_module_sp;
process->GetTarget().GetImages().Append(jit_module_sp,
true /* notify */);
}
}
if (process && m_jit_start_addr)
m_jit_process_wp = process->shared_from_this();
m_JITted = true;
return true;
}
bool FunctionCaller::WriteFunctionArguments(
ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
DiagnosticManager &diagnostic_manager) {
return WriteFunctionArguments(exe_ctx, args_addr_ref, m_arg_values,
diagnostic_manager);
}
// FIXME: Assure that the ValueList we were passed in is consistent with the one
// that defined this function.
bool FunctionCaller::WriteFunctionArguments(
ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
ValueList &arg_values, DiagnosticManager &diagnostic_manager) {
// All the information to reconstruct the struct is provided by the
// StructExtractor.
if (!m_struct_valid) {
diagnostic_manager.PutString(eDiagnosticSeverityError,
"Argument information was not correctly "
"parsed, so the function cannot be called.");
return false;
}
Status error;
lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
Process *process = exe_ctx.GetProcessPtr();
if (process == nullptr)
return return_value;
lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
if (process != jit_process_sp.get())
return false;
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;
}
}
// TODO: verify fun_addr needs to be a callable address
Scalar fun_addr(
m_function_addr.GetCallableLoadAddress(exe_ctx.GetTargetPtr()));
uint64_t first_offset = m_member_offsets[0];
process->WriteScalarToMemory(args_addr_ref + first_offset, fun_addr,
process->GetAddressByteSize(), error);
// FIXME: We will need to extend this for Variadic functions.
Status value_error;
size_t num_args = arg_values.GetSize();
if (num_args != m_arg_values.GetSize()) {
diagnostic_manager.Printf(
eDiagnosticSeverityError,
"Wrong number of arguments - was: %" PRIu64 " should be: %" PRIu64 "",
(uint64_t)num_args, (uint64_t)m_arg_values.GetSize());
return false;
}
for (size_t i = 0; i < num_args; i++) {
// FIXME: We should sanity check sizes.
uint64_t 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::ValueType::HostAddress &&
arg_value->GetContextType() == Value::ContextType::Invalid &&
arg_value->GetCompilerType().IsPointerType())
continue;
const Scalar &arg_scalar = arg_value->ResolveValue(&exe_ctx);
if (!process->WriteScalarToMemory(args_addr_ref + offset, arg_scalar,
arg_scalar.GetByteSize(), error))
return false;
}
return true;
}
bool FunctionCaller::InsertFunction(ExecutionContext &exe_ctx,
lldb::addr_t &args_addr_ref,
DiagnosticManager &diagnostic_manager) {
// Since we might need to call allocate memory and maybe call code to make
// the caller, we need to be stopped.
Process *process = exe_ctx.GetProcessPtr();
if (!process) {
diagnostic_manager.PutString(eDiagnosticSeverityError, "no process");
return false;
}
if (process->GetState() != lldb::eStateStopped) {
diagnostic_manager.PutString(eDiagnosticSeverityError, "process running");
return false;
}
if (CompileFunction(exe_ctx.GetThreadSP(), diagnostic_manager) != 0)
return false;
if (!WriteFunctionWrapper(exe_ctx, diagnostic_manager))
return false;
if (!WriteFunctionArguments(exe_ctx, args_addr_ref, diagnostic_manager))
return false;
Log *log = GetLog(LLDBLog::Step);
LLDB_LOGF(log, "Call Address: 0x%" PRIx64 " Struct Address: 0x%" PRIx64 ".\n",
m_jit_start_addr, args_addr_ref);
return true;
}
lldb::ThreadPlanSP FunctionCaller::GetThreadPlanToCallFunction(
ExecutionContext &exe_ctx, lldb::addr_t args_addr,
const EvaluateExpressionOptions &options,
DiagnosticManager &diagnostic_manager) {
Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step));
LLDB_LOGF(log,
"-- [FunctionCaller::GetThreadPlanToCallFunction] Creating "
"thread plan to call function \"%s\" --",
m_name.c_str());
// FIXME: Use the errors Stream for better error reporting.
Thread *thread = exe_ctx.GetThreadPtr();
if (thread == nullptr) {
diagnostic_manager.PutString(
eDiagnosticSeverityError,
"Can't call a function without a valid thread.");
return nullptr;
}
// Okay, now run the function:
Address wrapper_address(m_jit_start_addr);
lldb::addr_t args = {args_addr};
lldb::ThreadPlanSP new_plan_sp(new ThreadPlanCallFunction(
*thread, wrapper_address, CompilerType(), args, options));
new_plan_sp->SetIsControllingPlan(true);
new_plan_sp->SetOkayToDiscard(false);
return new_plan_sp;
}
bool FunctionCaller::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.
// FIXME: Create our ThreadPlanCallFunction with the return CompilerType, and
// then use GetReturnValueObject
// to fetch the value. That way we can fetch any values we need.
Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step));
LLDB_LOGF(log,
"-- [FunctionCaller::FetchFunctionResults] Fetching function "
"results for \"%s\"--",
m_name.c_str());
Process *process = exe_ctx.GetProcessPtr();
if (process == nullptr)
return false;
lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
if (process != jit_process_sp.get())
return false;
Status error;
ret_value.GetScalar() = process->ReadUnsignedIntegerFromMemory(
args_addr + m_return_offset, m_return_size, 0, error);
if (error.Fail())
return false;
ret_value.SetCompilerType(m_function_return_type);
ret_value.SetValueType(Value::ValueType::Scalar);
return true;
}
void FunctionCaller::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.GetProcessRef().DeallocateMemory(args_addr);
}
lldb::ExpressionResults FunctionCaller::ExecuteFunction(
ExecutionContext &exe_ctx, lldb::addr_t *args_addr_ptr,
const EvaluateExpressionOptions &options,
DiagnosticManager &diagnostic_manager, Value &results) {
lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
// FunctionCaller::ExecuteFunction execution is always just to get the
// result. Unless explicitly asked for, ignore breakpoints and unwind on
// error.
const bool enable_debugging =
exe_ctx.GetTargetPtr() &&
exe_ctx.GetTargetPtr()->GetDebugUtilityExpression();
EvaluateExpressionOptions real_options = options;
real_options.SetDebug(false); // This halts the expression for debugging.
real_options.SetGenerateDebugInfo(enable_debugging);
real_options.SetUnwindOnError(!enable_debugging);
real_options.SetIgnoreBreakpoints(!enable_debugging);
lldb::addr_t args_addr;
if (args_addr_ptr != nullptr)
args_addr = *args_addr_ptr;
else
args_addr = LLDB_INVALID_ADDRESS;
if (CompileFunction(exe_ctx.GetThreadSP(), diagnostic_manager) != 0)
return lldb::eExpressionSetupError;
if (args_addr == LLDB_INVALID_ADDRESS) {
if (!InsertFunction(exe_ctx, args_addr, diagnostic_manager))
return lldb::eExpressionSetupError;
}
Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step));
LLDB_LOGF(log,
"== [FunctionCaller::ExecuteFunction] Executing function \"%s\" ==",
m_name.c_str());
lldb::ThreadPlanSP call_plan_sp = GetThreadPlanToCallFunction(
exe_ctx, args_addr, real_options, diagnostic_manager);
if (!call_plan_sp)
return lldb::eExpressionSetupError;
// We need to make sure we record the fact that we are running an expression
// here otherwise this fact will fail to be recorded when fetching an
// Objective-C object description
if (exe_ctx.GetProcessPtr())
exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
return_value = exe_ctx.GetProcessRef().RunThreadPlan(
exe_ctx, call_plan_sp, real_options, diagnostic_manager);
if (log) {
if (return_value != lldb::eExpressionCompleted) {
LLDB_LOGF(log,
"== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
"completed abnormally: %s ==",
m_name.c_str(),
Process::ExecutionResultAsCString(return_value));
} else {
LLDB_LOGF(log,
"== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
"completed normally ==",
m_name.c_str());
}
}
if (exe_ctx.GetProcessPtr())
exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
if (args_addr_ptr != nullptr)
*args_addr_ptr = args_addr;
if (return_value != lldb::eExpressionCompleted)
return return_value;
FetchFunctionResults(exe_ctx, args_addr, results);
if (args_addr_ptr == nullptr)
DeallocateFunctionResults(exe_ctx, args_addr);
return lldb::eExpressionCompleted;
}
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