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//===-- FunctionCaller.h ----------------------------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLDB_EXPRESSION_FUNCTIONCALLER_H
#define LLDB_EXPRESSION_FUNCTIONCALLER_H
#include <list>
#include <memory>
#include <string>
#include <vector>
#include "lldb/Core/Address.h"
#include "lldb/Core/Value.h"
#include "lldb/Expression/Expression.h"
#include "lldb/Expression/ExpressionParser.h"
#include "lldb/Symbol/CompilerType.h"
namespace lldb_private {
/// \class FunctionCaller FunctionCaller.h "lldb/Expression/FunctionCaller.h"
/// Encapsulates a function that can be called.
///
/// A given FunctionCaller object can handle a single function signature.
/// Once constructed, it can set up any number of concurrent calls to
/// functions with that signature.
///
/// It performs the call by synthesizing a structure that contains the pointer
/// to the function and the arguments that should be passed to that function,
/// and producing a special-purpose JIT-compiled function that accepts a void*
/// pointing to this struct as its only argument and calls the function in the
/// struct with the written arguments. This method lets Clang handle the
/// vagaries of function calling conventions.
///
/// The simplest use of the FunctionCaller is to construct it with a function
/// representative of the signature you want to use, then call
/// ExecuteFunction(ExecutionContext &, Stream &, Value &).
///
/// If you need to reuse the arguments for several calls, you can call
/// InsertFunction() followed by WriteFunctionArguments(), which will return
/// the location of the args struct for the wrapper function in args_addr_ref.
///
/// If you need to call the function on the thread plan stack, you can also
/// call InsertFunction() followed by GetThreadPlanToCallFunction().
///
/// Any of the methods that take arg_addr_ptr or arg_addr_ref can be passed a
/// pointer set to LLDB_INVALID_ADDRESS and new structure will be allocated
/// and its address returned in that variable.
///
/// Any of the methods that take arg_addr_ptr can be passed nullptr, and the
/// argument space will be managed for you.
class FunctionCaller : public Expression {
// LLVM RTTI support
static char ID;
public:
bool isA(const void *ClassID) const override { return ClassID == &ID; }
static bool classof(const Expression *obj) { return obj->isA(&ID); }
/// Constructor
///
/// \param[in] exe_scope
/// An execution context scope that gets us at least a target and
/// process.
///
/// \param[in] return_type
/// An opaque Clang QualType for the function result. Should be
/// defined in ast_context.
///
/// \param[in] function_address
/// The address of the function to call.
///
/// \param[in] arg_value_list
/// The default values to use when calling this function. Can
/// be overridden using WriteFunctionArguments().
FunctionCaller(ExecutionContextScope &exe_scope,
const CompilerType &return_type,
const Address &function_address,
const ValueList &arg_value_list, const char *name);
/// Destructor
~FunctionCaller() override;
/// Compile the wrapper function
///
/// \param[in] thread_to_use_sp
/// Compilation might end up calling functions. Pass in the thread you
/// want the compilation to use. If you pass in an empty ThreadSP it will
/// use the currently selected thread.
///
/// \param[in] diagnostic_manager
/// The diagnostic manager to report parser errors to.
///
/// \return
/// The number of errors.
virtual unsigned CompileFunction(lldb::ThreadSP thread_to_use_sp,
DiagnosticManager &diagnostic_manager) = 0;
/// Insert the default function wrapper and its default argument struct
///
/// \param[in] exe_ctx
/// The execution context to insert the function and its arguments
/// into.
///
/// \param[in,out] args_addr_ref
/// The address of the structure to write the arguments into. May
/// be LLDB_INVALID_ADDRESS; if it is, a new structure is allocated
/// and args_addr_ref is pointed to it.
///
/// \param[in] diagnostic_manager
/// The diagnostic manager to report errors to.
///
/// \return
/// True on success; false otherwise.
bool InsertFunction(ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
DiagnosticManager &diagnostic_manager);
/// Insert the default function wrapper (using the JIT)
///
/// \param[in] exe_ctx
/// The execution context to insert the function and its arguments
/// into.
///
/// \param[in] diagnostic_manager
/// The diagnostic manager to report errors to.
///
/// \return
/// True on success; false otherwise.
bool WriteFunctionWrapper(ExecutionContext &exe_ctx,
DiagnosticManager &diagnostic_manager);
/// Insert the default function argument struct
///
/// \param[in] exe_ctx
/// The execution context to insert the function and its arguments
/// into.
///
/// \param[in,out] args_addr_ref
/// The address of the structure to write the arguments into. May
/// be LLDB_INVALID_ADDRESS; if it is, a new structure is allocated
/// and args_addr_ref is pointed to it.
///
/// \param[in] diagnostic_manager
/// The diagnostic manager to report errors to.
///
/// \return
/// True on success; false otherwise.
bool WriteFunctionArguments(ExecutionContext &exe_ctx,
lldb::addr_t &args_addr_ref,
DiagnosticManager &diagnostic_manager);
/// Insert an argument struct with a non-default function address and non-
/// default argument values
///
/// \param[in] exe_ctx
/// The execution context to insert the function and its arguments
/// into.
///
/// \param[in,out] args_addr_ref
/// The address of the structure to write the arguments into. May
/// be LLDB_INVALID_ADDRESS; if it is, a new structure is allocated
/// and args_addr_ref is pointed at it.
///
/// \param[in] arg_values
/// The values of the function's arguments.
///
/// \param[in] diagnostic_manager
/// The diagnostic manager to report errors to.
///
/// \return
/// True on success; false otherwise.
bool WriteFunctionArguments(ExecutionContext &exe_ctx,
lldb::addr_t &args_addr_ref,
ValueList &arg_values,
DiagnosticManager &diagnostic_manager);
/// Run the function this FunctionCaller was created with.
///
/// This is the full version.
///
/// \param[in] exe_ctx
/// The thread & process in which this function will run.
///
/// \param[in] args_addr_ptr
/// If nullptr, the function will take care of allocating & deallocating
/// the wrapper
/// args structure. Otherwise, if set to LLDB_INVALID_ADDRESS, a new
/// structure
/// will be allocated, filled and the address returned to you. You are
/// responsible
/// for deallocating it. And if passed in with a value other than
/// LLDB_INVALID_ADDRESS,
/// this should point to an already allocated structure with the values
/// already written.
///
/// \param[in] diagnostic_manager
/// The diagnostic manager to report errors to.
///
/// \param[in] options
/// The options for this expression execution.
///
/// \param[out] results
/// The result value will be put here after running the function.
///
/// \return
/// Returns one of the ExpressionResults enum indicating function call
/// status.
lldb::ExpressionResults
ExecuteFunction(ExecutionContext &exe_ctx, lldb::addr_t *args_addr_ptr,
const EvaluateExpressionOptions &options,
DiagnosticManager &diagnostic_manager, Value &results);
/// Get a thread plan to run the function this FunctionCaller was created
/// with.
///
/// \param[in] exe_ctx
/// The execution context to insert the function and its arguments
/// into.
///
/// \param[in] args_addr
/// The address of the argument struct.
///
/// \param[in] diagnostic_manager
/// The diagnostic manager to report errors to.
///
/// \return
/// A ThreadPlan shared pointer for executing the function.
lldb::ThreadPlanSP
GetThreadPlanToCallFunction(ExecutionContext &exe_ctx, lldb::addr_t args_addr,
const EvaluateExpressionOptions &options,
DiagnosticManager &diagnostic_manager);
/// Get the result of the function from its struct
///
/// \param[in] exe_ctx
/// The execution context to retrieve the result from.
///
/// \param[in] args_addr
/// The address of the argument struct.
///
/// \param[out] ret_value
/// The value returned by the function.
///
/// \return
/// True on success; false otherwise.
bool FetchFunctionResults(ExecutionContext &exe_ctx, lldb::addr_t args_addr,
Value &ret_value);
/// Deallocate the arguments structure
///
/// \param[in] exe_ctx
/// The execution context to insert the function and its arguments
/// into.
///
/// \param[in] args_addr
/// The address of the argument struct.
void DeallocateFunctionResults(ExecutionContext &exe_ctx,
lldb::addr_t args_addr);
/// Interface for ClangExpression
/// Return the string that the parser should parse. Must be a full
/// translation unit.
const char *Text() override { return m_wrapper_function_text.c_str(); }
/// Return the function name that should be used for executing the
/// expression. Text() should contain the definition of this function.
const char *FunctionName() override {
return m_wrapper_function_name.c_str();
}
/// Return the object that the parser should use when registering local
/// variables. May be nullptr if the Expression doesn't care.
ExpressionVariableList *LocalVariables() { return nullptr; }
/// Return true if validation code should be inserted into the expression.
bool NeedsValidation() override { return false; }
/// Return true if external variables in the expression should be resolved.
bool NeedsVariableResolution() override { return false; }
ValueList GetArgumentValues() const { return m_arg_values; }
protected:
// Note: the parser needs to be destructed before the execution unit, so
// declare the execution unit first.
std::shared_ptr<IRExecutionUnit> m_execution_unit_sp;
std::unique_ptr<ExpressionParser>
m_parser; ///< The parser responsible for compiling the function.
///< This will get made in CompileFunction, so it is
///< safe to access it after that.
lldb::ModuleWP m_jit_module_wp;
std::string
m_name; ///< The name of this clang function - for debugging purposes.
Function *m_function_ptr; ///< The function we're going to call. May be
///nullptr if we don't have debug info for the
///function.
Address m_function_addr; ///< If we don't have the FunctionSP, we at least
///need the address & return type.
CompilerType m_function_return_type; ///< The opaque clang qual type for the
///function return type.
std::string m_wrapper_function_name; ///< The name of the wrapper function.
std::string
m_wrapper_function_text; ///< The contents of the wrapper function.
std::string m_wrapper_struct_name; ///< The name of the struct that contains
///the target function address, arguments,
///and result.
std::list<lldb::addr_t> m_wrapper_args_addrs; ///< The addresses of the
///arguments to the wrapper
///function.
bool m_struct_valid; ///< True if the ASTStructExtractor has populated the
///variables below.
/// These values are populated by the ASTStructExtractor
size_t m_struct_size; ///< The size of the argument struct, in bytes.
std::vector<uint64_t>
m_member_offsets; ///< The offset of each member in the struct, in bytes.
uint64_t m_return_size; ///< The size of the result variable, in bytes.
uint64_t m_return_offset; ///< The offset of the result variable in the
///struct, in bytes.
ValueList m_arg_values; ///< The default values of the arguments.
bool m_compiled; ///< True if the wrapper function has already been parsed.
bool
m_JITted; ///< True if the wrapper function has already been JIT-compiled.
};
} // namespace lldb_private
#endif // LLDB_EXPRESSION_FUNCTIONCALLER_H