Hack of the day #1: Decompiling selected functions

Intended audience

IDA 7.2 users, who have experience with IDAPython and/or the decompiler.

The problem

As you may already know, the decompilers allow not only decompiling the current function (shortcut F5) but also all the functions in the database (shortcut Ctrl+F5).

A somewhat less-well known feature of the “multiple” decompilation, is that if a range is selected (for example in the IDA View-A), only functions within that range will be decompiled.

Alas this is not good enough for the use-case of one of users, who would like to be able to select entries in the list provided by the
Functions window, and decompile those (the biggest difference with the “IDA View-A range” approach, is that there can be gaps in the selection — functions that the user doesn’t want to spend time decompiling.)

The solution

Although IDA doesn’t provide a built-in solution for this particular use-case (it cannot cover them all), we can use IDA’s scriptability to come up with the following IDAPython script, which should offer a very satisfying implementation of the idea described above:

import ida_kernwin
import ida_funcs
import ida_hexrays

class decompile_selected_t(ida_kernwin.action_handler_t):
    def activate(self, ctx):
        out_path = ida_kernwin.ask_file(
            True,
            None,
            "Please specify the output file name");
        if out_path:
            eas = []
            for pfn_idx in ctx.chooser_selection:
                pfn = ida_funcs.getn_func(pfn_idx)
                if pfn:
                    eas.append(pfn.start_ea)
            ida_hexrays.decompile_many(out_path, eas, 0)
        return 1

    def update(self, ctx):
        if ctx.widget_type == ida_kernwin.BWN_FUNCS:
            return ida_kernwin.AST_ENABLE_FOR_WIDGET
        else:
            return ida_kernwin.AST_DISABLE_FOR_WIDGET

ACTION_NAME = "decompile-selected"

ida_kernwin.register_action(
    ida_kernwin.action_desc_t(
        ACTION_NAME,
        "Decompile selected",
        decompile_selected_t(),
        "Ctrl+F5"))

class popup_hooks_t(ida_kernwin.UI_Hooks):
    def finish_populating_widget_popup(self, w, popup):
        if ida_kernwin.get_widget_type(w) == ida_kernwin.BWN_FUNCS:
            ida_kernwin.attach_action_to_popup(
                w,
                popup,
                ACTION_NAME,
                None)

hooks = popup_hooks_t()
hooks.hook()