lldb/source/Plugins/ExpressionParser/Clang/ClangFunctionCaller.cpp

//===-- ClangFunctionCallerCaller.cpp ---------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "ClangFunctionCaller.h"

#include "ASTStructExtractor.h"
#include "ClangExpressionParser.h"

// 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/Core/DataExtractor.h"
#include "lldb/Core/Log.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/State.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Core/ValueObjectList.h"
#include "lldb/Expression/IRExecutionUnit.h"
#include "lldb/Interpreter/CommandReturnObject.h"
#include "lldb/Symbol/ClangASTContext.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"

using namespace lldb_private;

//----------------------------------------------------------------------
// ClangFunctionCaller constructor
//----------------------------------------------------------------------
ClangFunctionCaller::ClangFunctionCaller 
(
    ExecutionContextScope &exe_scope,
    const CompilerType &return_type, 
    const Address& functionAddress, 
    const ValueList &arg_value_list,
    const char *name
) :
    FunctionCaller(exe_scope, return_type, functionAddress, arg_value_list, name),
    m_type_system_helper (*this)
{
    m_jit_process_wp = lldb::ProcessWP(exe_scope.CalculateProcess());
    // Can't make a ClangFunctionCaller without a process.
    assert (m_jit_process_wp.lock());
}

//----------------------------------------------------------------------
// Destructor
//----------------------------------------------------------------------
ClangFunctionCaller::~ClangFunctionCaller()
{
}

unsigned
ClangFunctionCaller::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 (m_function_return_type.GetTypeName().AsCString(""));
    
    // 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.
    CompilerType function_clang_type;
    if (m_function_ptr)
    {
        function_clang_type = m_function_ptr->GetCompilerType();
        if (function_clang_type)
        {
            int num_func_args = function_clang_type.GetFunctionArgumentCount();
            if (num_func_args >= 0)
            {
                trust_function = true;
                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)
        {
            type_name = function_clang_type.GetFunctionArgumentTypeAtIndex(i).GetTypeName().AsCString("");
        }
        else
        {
            CompilerType clang_qual_type = m_arg_values.GetValueAtIndex(i)->GetCompilerType ();
            if (clang_qual_type)
            {
                type_name = clang_qual_type.GetTypeName().AsCString("");
            }
            else
            {   
                errors.Printf("Could not determine type of input value %" PRIu64 ".", (uint64_t)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)
    {
        const bool generate_debug_info = true;
        m_parser.reset(new ClangExpressionParser(jit_process_sp.get(), *this, generate_debug_info));
        
        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;
}

clang::ASTConsumer *
ClangFunctionCaller::ClangFunctionCallerHelper::ASTTransformer (clang::ASTConsumer *passthrough)
{
    m_struct_extractor.reset(new ASTStructExtractor(passthrough, m_owner.GetWrapperStructName(), m_owner));
    
    return m_struct_extractor.get();
}