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llvm-project/lldb/source/Expression/ClangFunction.cpp
Sean Callanan 5a1af4e63a Factored out memory access into the target process 
from IRExecutionUnit into a superclass called
IRMemoryMap.  IRMemoryMap handles all reading and
writing, ensuring that areas are kept track of and
memory is properly cached (and deleted).

Also fixed several cases where we would simply leak
binary data in the target process over time.  Now
the expression objects explicitly own their
IRExecutionUnit and delete it when they go away.  This
is why I had to modify ClangUserExpression,
ClangUtilityFunction, and ClangFunction.

As a side effect of this, I am removing the JIT
mutex for an IRMemoryMap.  If it turns out that we
need this mutex, I'll add it in then, but right now
it's just adding complexity.

This is part of a more general project to make
expressions fully reusable.  The next step is to
make materialization and dematerialization use
the IRMemoryMap API rather than writing and
reading directly from the process's memory. 
This will allow the IR interpreter to use the
same data, but in the host's memory, without having
to use a different set of pointers.

llvm-svn: 178832
2013-04-05 02:22:57 +00:00

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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/ADT/Triple.h"
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/IR/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/Target.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
(
ExecutionContextScope &exe_scope,
ClangASTContext *ast_context,
void *return_qualtype,
const Address& functionAddress,
const ValueList &arg_value_list
) :
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_args_addrs (),
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 ClangFunction without a process.
assert (m_jit_process_wp.lock());
}
ClangFunction::ClangFunction
(
ExecutionContextScope &exe_scope,
Function &function,
ClangASTContext *ast_context,
const ValueList &arg_value_list
) :
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_args_addrs (),
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 ClangFunction without a process.
assert (m_jit_process_wp.lock());
m_function_addr = m_function_ptr->GetAddressRange().GetBaseAddress();
m_function_return_qual_type = m_function_ptr->GetReturnClangType();
}
//----------------------------------------------------------------------
// 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 (ClangASTType::GetTypeNameForOpaqueQualType (m_clang_ast_context->getASTContext(),
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.
size_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++)
{
std::string type_name;
if (trust_function)
{
lldb::clang_type_t arg_clang_type = m_function_ptr->GetArgumentTypeAtIndex(i);
type_name = ClangASTType::GetTypeNameForOpaqueQualType (m_clang_ast_context->getASTContext(),
arg_clang_type);
}
else
{
Value *arg_value = m_arg_values.GetValueAtIndex(i);
lldb::clang_type_t clang_qual_type = arg_value->GetClangType ();
if (clang_qual_type != NULL)
{
type_name = ClangASTType::GetTypeNameForOpaqueQualType (m_clang_ast_context->getASTContext(),
clang_qual_type);
}
else
{
errors.Printf("Could not determine type of input value %lu.", i);
return 1;
}
}
m_wrapper_function_text.append (type_name);
if (i < num_args - 1)
m_wrapper_function_text.append (", ");
char arg_buf[32];
args_buffer.append (" ");
args_buffer.append (type_name);
snprintf(arg_buf, 31, "arg_%" PRIu64, (uint64_t)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");
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_EXPRESSIONS));
if (log)
log->Printf ("Expression: \n\n%s\n\n", m_wrapper_function_text.c_str());
// Okay, now compile this expression
lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
if (jit_process_sp)
{
m_parser.reset(new ClangExpressionParser(jit_process_sp.get(), *this));
num_errors = m_parser->Parse (errors);
}
else
{
errors.Printf("no process - unable to inject function");
num_errors = 1;
}
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.GetProcessPtr();
if (!process)
return false;
lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
if (process != jit_process_sp.get())
return false;
if (!m_compiled)
return false;
if (m_JITted)
return true;
lldb::ClangExpressionVariableSP const_result;
bool evaluated_statically = false; // should stay that way
Error jit_error (m_parser->PrepareForExecution (m_jit_start_addr,
m_jit_end_addr,
m_execution_unit_ap,
exe_ctx,
evaluated_statically,
const_result,
eExecutionPolicyAlways));
if (!jit_error.Success())
return false;
if (process && m_jit_start_addr)
m_jit_process_wp = lldb::ProcessWP(process->shared_from_this());
m_JITted = true;
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.GetProcessPtr();
if (process == NULL)
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 (function_address.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.
Error value_error;
size_t num_args = arg_values.GetSize();
if (num_args != m_arg_values.GetSize())
{
errors.Printf ("Wrong number of arguments - was: %lu should be: %lu", num_args, 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::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());
if (!process->WriteScalarToMemory(args_addr_ref + offset, arg_scalar, arg_scalar.GetByteSize(), error))
return false;
}
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;
Log *log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_STEP));
if (log)
log->Printf ("Call Address: 0x%" PRIx64 " Struct Address: 0x%" PRIx64 ".\n", m_jit_start_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 unwind_on_error,
bool ignore_breakpoints,
lldb::addr_t *this_arg,
lldb::addr_t *cmd_arg)
{
Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_EXPRESSIONS | LIBLLDB_LOG_STEP));
if (log)
log->Printf("-- [ClangFunction::GetThreadPlanToCallFunction] Creating thread plan to call function --");
// FIXME: Use the errors Stream for better error reporting.
Thread *thread = exe_ctx.GetThreadPtr();
if (thread == NULL)
{
errors.Printf("Can't call a function without a valid thread.");
return NULL;
}
// Okay, now run the function:
Address wrapper_address (func_addr);
ThreadPlan *new_plan = new ThreadPlanCallFunction (*thread,
wrapper_address,
ClangASTType(),
args_addr,
stop_others,
unwind_on_error,
ignore_breakpoints,
this_arg,
cmd_arg);
new_plan->SetIsMasterPlan(true);
new_plan->SetOkayToDiscard (false);
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.
// FIXME: Create our ThreadPlanCallFunction with the return ClangASTType, and then use GetReturnValueObject
// to fetch the value. That way we can fetch any values we need.
Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_EXPRESSIONS | LIBLLDB_LOG_STEP));
if (log)
log->Printf("-- [ClangFunction::FetchFunctionResults] Fetching function results --");
Process *process = exe_ctx.GetProcessPtr();
if (process == NULL)
return false;
lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
if (process != jit_process_sp.get())
return false;
Error error;
ret_value.GetScalar() = process->ReadUnsignedIntegerFromMemory (args_addr + m_return_offset, m_return_size, 0, error);
if (error.Fail())
return false;
ret_value.SetContext (Value::eContextTypeClangType, m_function_return_qual_type);
ret_value.SetValueType(Value::eValueTypeScalar);
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.GetProcessRef().DeallocateMemory(args_addr);
}
ExecutionResults
ClangFunction::ExecuteFunction(ExecutionContext &exe_ctx, Stream &errors, Value &results)
{
return ExecuteFunction (exe_ctx, errors, 1000, true, results);
}
ExecutionResults
ClangFunction::ExecuteFunction(ExecutionContext &exe_ctx, Stream &errors, bool stop_others, Value &results)
{
const bool try_all_threads = false;
const bool unwind_on_error = true;
const bool ignore_breakpoints = true;
return ExecuteFunction (exe_ctx, NULL, errors, stop_others, 0UL, try_all_threads,
unwind_on_error, ignore_breakpoints, results);
}
ExecutionResults
ClangFunction::ExecuteFunction(
ExecutionContext &exe_ctx,
Stream &errors,
uint32_t timeout_usec,
bool try_all_threads,
Value &results)
{
const bool stop_others = true;
const bool unwind_on_error = true;
const bool ignore_breakpoints = true;
return ExecuteFunction (exe_ctx, NULL, errors, stop_others, timeout_usec,
try_all_threads, unwind_on_error, ignore_breakpoints, results);
}
// This is the static function
ExecutionResults
ClangFunction::ExecuteFunction (
ExecutionContext &exe_ctx,
lldb::addr_t function_address,
lldb::addr_t &void_arg,
bool stop_others,
bool try_all_threads,
bool unwind_on_error,
bool ignore_breakpoints,
uint32_t timeout_usec,
Stream &errors,
lldb::addr_t *this_arg)
{
Log *log(lldb_private::GetLogIfAnyCategoriesSet (LIBLLDB_LOG_EXPRESSIONS | LIBLLDB_LOG_STEP));
if (log)
log->Printf("== [ClangFunction::ExecuteFunction] Executing function ==");
lldb::ThreadPlanSP call_plan_sp (ClangFunction::GetThreadPlanToCallFunction (exe_ctx,
function_address,
void_arg,
errors,
stop_others,
unwind_on_error,
ignore_breakpoints,
this_arg));
if (!call_plan_sp)
return eExecutionSetupError;
// <rdar://problem/12027563> 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);
ExecutionResults results = exe_ctx.GetProcessRef().RunThreadPlan (exe_ctx, call_plan_sp,
stop_others,
try_all_threads,
unwind_on_error,
ignore_breakpoints,
timeout_usec,
errors);
if (log)
{
if (results != eExecutionCompleted)
{
log->Printf("== [ClangFunction::ExecuteFunction] Execution completed abnormally ==");
}
else
{
log->Printf("== [ClangFunction::ExecuteFunction] Execution completed normally ==");
}
}
if (exe_ctx.GetProcessPtr())
exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
return results;
}
ExecutionResults
ClangFunction::ExecuteFunction(
ExecutionContext &exe_ctx,
lldb::addr_t *args_addr_ptr,
Stream &errors,
bool stop_others,
uint32_t timeout_usec,
bool try_all_threads,
bool unwind_on_error,
bool ignore_breakpoints,
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_jit_start_addr,
args_addr,
stop_others,
try_all_threads,
unwind_on_error,
ignore_breakpoints,
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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