Extra LLVM formatters

extra_formatters.py

"""
Extra LLDB Formatters

Contains formatters for:
- `llvm::SmallVector` - https://llvm.org/doxygen/classllvm_1_1SmallVector.html
- `boost::container::flat_map` - https://www.boost.org/doc/libs/1_69_0/doc/html/boost/container/flat_map.html
- `boost::optional` - https://www.boost.org/doc/libs/1_69_0/libs/optional/doc/html/index.html
- `mpark::variant` - https://github.com/mpark/variant

Load into LLDB with `command script import /path/to/extra-formatters.py`
or add this command to `~/.lldbinit`

Links:
- https://lldb.llvm.org/varformats.html
- https://github.com/llvm/llvm-project/tree/master/lldb/examples
- https://github.com/llvm/llvm-project/blob/master/llvm/utils/lldbDataFormatters.py
"""


def __lldb_init_module(debugger, internal_dict):
    debugger.HandleCommand('type category define -e oliora -l c++')

    debugger.HandleCommand('type synthetic add -w oliora -l extra_formatters.LlvmSmallVectorSynthProvider -x "^llvm::SmallVectorImpl<.+>$"')
    debugger.HandleCommand('type summary add --expand -x "^llvm::SmallVectorImpl<.+>$" --summary-string "${svar%#} items')

    debugger.HandleCommand('type synthetic add -w oliora -l extra_formatters.LlvmSmallVectorSynthProvider -x "^llvm::SmallVector<.+,.+>$"')
    debugger.HandleCommand('type summary add --expand -x "^llvm::SmallVector<.+,.+>$" --summary-string "${svar%#} items')

    debugger.HandleCommand('type synthetic add -w oliora -l extra_formatters.BoostFlatMapSynthProvider -x "^boost::container::flat_map<.+>$"')
    debugger.HandleCommand('type summary add --expand -x "^boost::container::flat_map<.+>$" --summary-string "${svar%#} items')

    debugger.HandleCommand('type synthetic add -w oliora -l extra_formatters.BoostOptionalSynthProvider -x "^boost::optional<.+>$"')
    debugger.HandleCommand('type summary add --inline-children -w oliora -x "^boost::optional<.+>$"')

    debugger.HandleCommand('type synthetic add -w oliora -l extra_formatters.MparkVariantSynthProvider -x "^mpark::variant<.+>$"')
    debugger.HandleCommand('type summary add --inline-children -w oliora -x "^mpark::variant<.+>$"')


class LlvmSmallVectorSynthProvider:
    def __init__(self, valobj, dict):
        self.valobj = valobj;
        self.update()

    def num_children(self):
        begin = self.begin.GetValueAsUnsigned(0)
        end = self.end.GetValueAsUnsigned(0)
        if (begin >= end) or not begin or not end or not self.type_size:
            return 0;
        distance = end - begin
        if distance % self.type_size:
            return 0
        return distance / self.type_size

    def get_child_index(self, name):
        try:
            return int(name.lstrip('[').rstrip(']'))
        except:
            return -1;

    def get_child_at_index(self, index):
        if index < 0 or index >= self.num_children():
            return None;

        offset = index * self.type_size
        return self.begin.CreateChildAtOffset('['+str(index)+']', offset, self.value_type)

    def update(self):
        self.begin = self.valobj.GetChildMemberWithName('BeginX')
        self.end = self.valobj.GetChildMemberWithName('EndX')

        the_type = self.valobj.GetType()
        if the_type.IsReferenceType():
            the_type = the_type.GetDereferencedType()

        self.value_type = the_type.GetTemplateArgumentType(0)
        self.type_size = self.value_type.GetByteSize()


# TODO: also show comparator
class BoostFlatMapSynthProvider:
    def __init__(self, valobj, dict):
        self.valobj = valobj;
        self.update()

    def num_children(self):
        if self.size < 0:
            return 0
        return self.size.GetValueAsUnsigned(0)

    def get_child_index(self, name):
        try:
            return int(name.lstrip('[').rstrip(']'))
        except:
            return -1;

    def get_child_at_index(self, index):
        if index < 0 or index >= self.num_children():
            return None;

        offset = index * self.type_size
        return self.data.CreateChildAtOffset('['+str(index)+']', offset, self.value_type)

    def update(self):
        boost_vector = self.valobj.GetChildMemberWithName('m_flat_tree').GetChildMemberWithName('m_data').GetChildMemberWithName('m_seq')
        holder = boost_vector.GetChildMemberWithName('m_holder')
        self.data = holder.GetChildMemberWithName('m_start')
        self.size = holder.GetChildMemberWithName('m_size')

        the_type = boost_vector.GetType()
        if the_type.IsReferenceType():
            the_type = the_type.GetDereferencedType()

        self.value_type = the_type.GetTemplateArgumentType(0)
        self.type_size = self.value_type.GetByteSize()


class BoostOptionalSynthProvider:
    def __init__(self, valobj, dict):
        self.valobj = valobj;
        self.update()

    def num_children(self):
        return 1

    def get_child_index(self, name):
        try:
            return int(name.lstrip('[').rstrip(']'))
        except:
            return -1;

    def get_child_at_index(self, index):
        num_children = 1 if self.initialized.GetValueAsUnsigned() == 1 else 0
        if index < 0 or index >= num_children:
            return None;

        return self.storage.CreateChildAtOffset('value_', 0, self.value_type)

    def update(self):
        self.initialized = self.valobj.GetChildMemberWithName('m_initialized')

        the_type = self.valobj.GetType()
        if the_type.IsReferenceType():
            the_type = self.the_type.GetDereferencedType()
        self.value_type = the_type.GetTemplateArgumentType(0)

        self.storage = self.valobj.GetChildMemberWithName('m_storage').GetChildMemberWithName('dummy_')


def get_recursive_union_types(union_type):
    while True:
        head = union_type.GetChildMemberWithName('head_')
        if not head.IsValid():
            return
        yield head.GetType().GetTemplateArgumentType(1)
        union_type = union_type.GetChildMemberWithName('tail_')


class MparkVariantSynthProvider:
    def __init__(self, valobj, dict):
        self.valobj = valobj;
        self.update()

    def num_children(self):
        return 2

    def get_child_index(self, name):
        try:
            return int(name.lstrip('[').rstrip(']'))
        except:
            return -1;

    def get_child_at_index(self, index):
        if index == 0:
            return self.index
        elif index == 1:
            index = self.index.GetValueAsSigned()
            if index < 0:
                return None
            value_type = self.types[index]
            return self.storage.Cast(value_type)
        else:
            return None

    def update(self):
        impl = self.valobj.GetChildMemberWithName('impl_')
        self.index = impl.GetChildMemberWithName('index_')
        self.storage = impl.GetChildMemberWithName('data_')
        self.types = list(t for t in get_recursive_union_types(self.storage))