#include <libasr/asr.h>
#include <libasr/containers.h>
#include <libasr/exception.h>
#include <libasr/asr_utils.h>
#include <libasr/asr_verify.h>
#include <libasr/pass/pass_utils.h>
#include <libasr/pass/array_by_data.h>
#include <libasr/asr_builder.h>

#include <vector>
#include <utility>
#include <deque>
#include <set>

/*
This ASR to ASR pass can be called whenever you want to avoid
using descriptors for passing arrays to functions/subroutines
in the backend. By default, it is currently being used by all
the backends (via pass manager). Backends like WASM which
do not support array descriptors always need this pass
to be called.

The possibility to avoid descriptors and pass array by data
to functions/subroutines is determined by ASRUtils::is_pass_array_by_data_possible
defined in asr_utils.h.

Advantages and dis-advantages of this pass are as follows,

Advantages:

* Avoiding array descriptors and just using simple data points leads to
easier handling in the backend.

* A lot of indirection to access dimensional information is also avoided
because it is already provided via extra variable arguments.

Dis-advantages:

* Requires access to all the code, as function interfaces have to be modified. Hence, not always possible.

* The arrays become contiguous, which most of the time is fine, but sometimes you might lose performance.

*/


namespace LCompilers {

// After duplicating a function body and its symbol table, BlockCall statements
// still reference the original Block symbols. This visitor remaps them to the
// corresponding duplicated Blocks in the new symbol table.
class BlockCallRemapper : public ASR::BaseWalkVisitor<BlockCallRemapper> {
    SymbolTable* new_symtab;
public:
    BlockCallRemapper(SymbolTable* new_symtab_) : new_symtab(new_symtab_) {}

    void visit_BlockCall(const ASR::BlockCall_t& x) {
        ASR::BlockCall_t& xx = const_cast<ASR::BlockCall_t&>(x);
        if (ASR::is_a<ASR::Block_t>(*xx.m_m)) {
            std::string block_name = ASR::down_cast<ASR::Block_t>(xx.m_m)->m_name;
            ASR::symbol_t* new_block = new_symtab->get_symbol(block_name);
            if (new_block) {
                xx.m_m = new_block;
            }
        }
    }

    void visit_AssociateBlockCall(const ASR::AssociateBlockCall_t& x) {
        ASR::AssociateBlockCall_t& xx = const_cast<ASR::AssociateBlockCall_t&>(x);
        if (ASR::is_a<ASR::AssociateBlock_t>(*xx.m_m)) {
            std::string block_name = ASR::down_cast<ASR::AssociateBlock_t>(xx.m_m)->m_name;
            ASR::symbol_t* new_block = new_symtab->get_symbol(block_name);
            if (new_block) {
                xx.m_m = new_block;
            }
        }
    }
};

static void remap_block_calls(Vec<ASR::stmt_t*>& body,
        SymbolTable* /*old_symtab*/, SymbolTable* new_symtab) {
    BlockCallRemapper remapper(new_symtab);
    for (size_t i = 0; i < body.size(); i++) {
        remapper.visit_stmt(*body[i]);
    }
}

/*
The following visitor converts function/subroutines (a.k.a procedures)
with array arguments having empty dimensions to arrays having dimensional
information available from function arguments. See example below,

    subroutine f(array1, array2)
        integer, intent(in) :: array1(:)
        integer, intent(out) :: array2(:)
    end subroutine

gets converted to,

    subroutine f_array1_array2(array1, m1, n1, array2, m2, n2)
        integer, intent(in) :: m1, m2, n1, n2
        integer, intent(in) :: array1(m1:n1)
        integer, intent(out) :: array2(m2:n2)
    end subroutine
 */
class PassArrayByDataProcedureVisitor : public PassUtils::PassVisitor<PassArrayByDataProcedureVisitor>
{
    private:

        ASRUtils::ExprStmtDuplicator node_duplicator;
        const LCompilers::PassOptions& pass_options;

    public:

        std::map< ASR::symbol_t*, std::pair<ASR::symbol_t*, std::vector<size_t>> > proc2newproc;
        std::set<ASR::symbol_t*> newprocs;

        PassArrayByDataProcedureVisitor(Allocator& al_, const LCompilers::PassOptions& pass_options_) :
        PassVisitor(al_, nullptr), node_duplicator(al_), pass_options(pass_options_)
        {}

        int get_index_kind() const {
            return pass_options.descriptor_index_64 ? 8 : 4;
        }

        ASR::symbol_t* insert_new_procedure(ASR::Function_t* x, std::vector<size_t>& indices) {
            Vec<ASR::stmt_t*> new_body;
            new_body.reserve(al, x->n_body);
            node_duplicator.allow_procedure_calls = true;
            node_duplicator.allow_reshape = false;
            for( size_t i = 0; i < x->n_body; i++ ) {
                node_duplicator.success = true;
                ASR::stmt_t* new_stmt = node_duplicator.duplicate_stmt(x->m_body[i]);
                if( !node_duplicator.success ) {
                    return nullptr;
                }
                new_body.push_back(al, new_stmt);
            }

            node_duplicator.allow_procedure_calls = true;
            SymbolTable* new_symtab = al.make_new<SymbolTable>(current_scope);
            ASRUtils::SymbolDuplicator symbol_duplicator(al);
            // first duplicate the external symbols
            // so they can be referenced by derived_type
            for( auto& item: x->m_symtab->get_scope() ) {
                if (ASR::is_a<ASR::ExternalSymbol_t>(*item.second)) {
                    symbol_duplicator.duplicate_symbol(item.second, new_symtab);
                }
            }
            for( auto& item: x->m_symtab->get_scope() ) {
                if (!ASR::is_a<ASR::ExternalSymbol_t>(*item.second)) {
                    symbol_duplicator.duplicate_symbol(item.second, new_symtab);
                }
            }
            // The duplicated body's BlockCall statements still reference
            // Block symbols in the original symtab. Remap them to the
            // corresponding duplicated Blocks in new_symtab.
            remap_block_calls(new_body, x->m_symtab, new_symtab);

            Vec<ASR::expr_t*> new_args;
            std::string suffix = "";
            new_args.reserve(al, x->n_args);
            ASR::expr_t* return_var = nullptr;
            for( size_t i = 0; i < x->n_args + 1; i++ ) {
                ASR::Variable_t* arg = nullptr;
                ASR::Function_t* arg_func = nullptr;
                if( i < x->n_args ) {
                    if (ASR::is_a<ASR::Var_t>(*(x->m_args[i]))) {
                        ASR::Var_t* x_arg = ASR::down_cast<ASR::Var_t>(x->m_args[i]);
                        if (ASR::is_a<ASR::Function_t>(*(x_arg->m_v))) {
                            arg_func = ASR::down_cast<ASR::Function_t>(x_arg->m_v);
                        } else {
                            arg = ASRUtils::EXPR2VAR(x->m_args[i]);
                        }
                    }
                } else if( x->m_return_var ) {
                    arg = ASRUtils::EXPR2VAR(x->m_return_var);
                } else {
                    break ;
                }
                if( std::find(indices.begin(), indices.end(), i) != indices.end() ) {
                    if( arg_func ) {
                        suffix += "_" + ASRUtils::type_to_str_fortran_expr(arg_func->m_function_signature, 
                            ASRUtils::get_expr_from_sym(al, &arg_func->base));
                    } else {
                        suffix += "_" + ASRUtils::type_to_str_fortran_symbol(arg->m_type, 
                            arg->m_type_declaration);
                    }
                    suffix += "_" + std::to_string(i);
                }
                ASR::expr_t* new_arg;
                if (arg_func) {
                    new_arg = ASRUtils::EXPR(ASR::make_Var_t(al,
                                        arg_func->base.base.loc, new_symtab->get_symbol(
                                                        std::string(arg_func->m_name))));
                } else {
                    new_arg = ASRUtils::EXPR(ASR::make_Var_t(al,
                                        arg->base.base.loc, new_symtab->get_symbol(
                                                        std::string(arg->m_name))));
                }
                if( i < x->n_args ) {
                    new_args.push_back(al, new_arg);
                } else {
                    return_var = new_arg;
                }
            }
            ASR::symbol_t* new_symbol = nullptr;
            suffix = to_lower(suffix);
            for( size_t suffixi = 0; suffixi < suffix.size(); suffixi++ ) {
                if( !((suffix[suffixi] >= 'a' && suffix[suffixi] <= 'z') ||
                    (suffix[suffixi] >= '0' && suffix[suffixi] <= '9')) ) {
                    suffix[suffixi] = '_';
                }
            }
            std::string new_name = std::string(x->m_name) + suffix;
            // In interactive mode the global symbol table persists across
            // evaluations and the pass may run multiple times. If the
            // generated procedure already exists in the current scope from
            // a previous run, skip re-processing this function (which would
            // trip add_symbol's uniqueness assertion). Call sites in the
            // freshly translated AST will be rewritten by the call-site
            // replacer using existing proc2newproc state populated below
            // for newly inserted procedures only.
            if (current_scope->get_symbol(new_name) != nullptr) {
                return nullptr;
            }
            if( ASR::is_a<ASR::Function_t>( *((ASR::symbol_t*) x) ) ) {
                ASR::FunctionType_t* x_func_type = ASRUtils::get_FunctionType(x);
                std::string new_bindc_name = "";
                if( x_func_type->m_bindc_name ) {
                    new_bindc_name = std::string(x_func_type->m_bindc_name) + suffix;
                }
                ASR::asr_t* new_subrout = ASRUtils::make_Function_t_util(al, x->base.base.loc,
                    new_symtab, s2c(al, new_name), x->m_dependencies, x->n_dependencies,
                    new_args.p, new_args.size(),  new_body.p, new_body.size(),
                    return_var, x_func_type->m_abi, x->m_access, x_func_type->m_deftype,
                    s2c(al, new_bindc_name), x_func_type->m_elemental,
                    x_func_type->m_pure, x_func_type->m_module, x_func_type->m_inline,
                    x_func_type->m_static,
                    x_func_type->m_restrictions, x_func_type->n_restrictions, false, false, false);
                new_symbol = ASR::down_cast<ASR::symbol_t>(new_subrout);
            }
            current_scope->add_symbol(new_name, new_symbol);
            proc2newproc[(ASR::symbol_t*) x] = std::make_pair(new_symbol, indices);
            newprocs.insert(new_symbol);
            return new_symbol;
        }

        void edit_new_procedure_args(ASR::Function_t* x, std::vector<size_t>& indices) {
            Vec<ASR::expr_t*> new_args;
            new_args.reserve(al, x->n_args);
            for( size_t i = 0; i < x->n_args; i++ ) {
                new_args.push_back(al, x->m_args[i]);
                if( std::find(indices.begin(), indices.end(), i) !=
                    indices.end() ) {
                    ASR::Variable_t* arg = ASRUtils::EXPR2VAR(x->m_args[i]);
                    ASR::dimension_t* dims = nullptr;
                    int n_dims = ASRUtils::extract_dimensions_from_ttype(arg->m_type, dims);

                    // Check if this is an assumed-size array (UnboundedPointerArray)
                    // If so, don't add dimension variables - keep dimensions as-is
                    ASR::array_physical_typeType phys_type = ASRUtils::extract_physical_type(arg->m_type);
                    if (phys_type == ASR::array_physical_typeType::UnboundedPointerArray) {
                        // Don't modify assumed-size arrays - they don't pass dimension info
                        continue;
                    }

                    Vec<ASR::expr_t*> dim_variables;
                    std::string arg_name = std::string(arg->m_name);
                    int index_kind = get_index_kind();
                    PassUtils::create_vars(dim_variables, n_dims, arg->base.base.loc, al,
                                            x->m_symtab, arg_name, ASR::intentType::In, arg->m_presence, index_kind);
                    Vec<ASR::dimension_t> new_dims;
                    new_dims.reserve(al, n_dims);
                    ASRUtils::ASRBuilder builder(al, arg->base.base.loc);
                    for( int j = 0, k = 0; j < n_dims; j++ ) {
                        ASR::dimension_t new_dim;
                        new_dim.loc = dims[j].loc;
                        if (dims[j].m_start) {
                            new_dim.m_start = dims[j].m_start;
                        } else {
                            new_dim.m_start = builder.i_idx(1, index_kind);
                        }
                        new_dim.m_length = dim_variables[k];
                        new_dims.push_back(al, new_dim);
                        k += 1;
                    }
                    ASR::ttype_t* new_type = ASRUtils::duplicate_type(al, arg->m_type, &new_dims);
                    arg->m_type = new_type;
                    for( int k = 0; k < n_dims; k++ ) {
                        new_args.push_back(al, dim_variables[k]);
                    }
                }
            }

            ASR::FunctionType_t* func_type = ASRUtils::get_FunctionType(*x);
            x->m_function_signature = ASRUtils::TYPE(ASRUtils::make_FunctionType_t_util(
                al, func_type->base.base.loc, new_args.p, new_args.size(), x->m_return_var, func_type, current_scope));
            x->m_args = new_args.p;
            x->n_args = new_args.size();
        }


        template <typename T>
        bool visit_SymbolContainingFunctions(const T& x,
            std::deque<ASR::Function_t*>& pass_array_by_data_functions) {
            T& xx = const_cast<T&>(x);
            current_scope = xx.m_symtab;
            for( auto& item: xx.m_symtab->get_scope() ) {
                if( ASR::is_a<ASR::Function_t>(*item.second) ) {
                    ASR::Function_t* subrout = ASR::down_cast<ASR::Function_t>(item.second);
                    pass_array_by_data_functions.push_back(subrout);
                    std::vector<size_t> arg_indices;
                    if( ASRUtils::is_pass_array_by_data_possible(subrout, arg_indices) ) {
                        ASR::symbol_t* sym = insert_new_procedure(subrout, arg_indices);
                        if( sym != nullptr ) {
                            ASR::Function_t* new_subrout = ASR::down_cast<ASR::Function_t>(sym);
                            edit_new_procedure_args(new_subrout, arg_indices);
                        }
                    }
                }
            }
            return pass_array_by_data_functions.size() > 0;
        }

        #define bfs_visit_SymbolContainingFunctions() std::deque<ASR::Function_t*> pass_array_by_data_functions;    \
            visit_SymbolContainingFunctions(x, pass_array_by_data_functions);    \
            while( pass_array_by_data_functions.size() > 0 ) {    \
                ASR::Function_t* function = pass_array_by_data_functions.front();    \
                pass_array_by_data_functions.pop_front();    \
                visit_SymbolContainingFunctions(*function, pass_array_by_data_functions);    \
            }    \

        void visit_TranslationUnit(const ASR::TranslationUnit_t& x) {
            // Visit functions in global scope first
            bfs_visit_SymbolContainingFunctions();

            // Visit Module so that all functions in it are updated
            for (auto &a : x.m_symtab->get_scope()) {
                if( ASR::is_a<ASR::Module_t>(*a.second) ) {
                    this->visit_symbol(*a.second);
                }
            }

            // When a module has submodules, the Interface declaration
            // (empty body) can be transformed but the Implementation
            // (in the submodule) may fail (e.g. body contains reshape).
            // Remove such Interface entries so callers are not redirected
            // to a function that has no definition.
            std::vector<ASR::symbol_t*> iface_to_remove;
            for (auto& kv : proc2newproc) {
                ASR::Function_t* func = ASR::down_cast<ASR::Function_t>(kv.first);
                ASR::FunctionType_t* ftype = ASRUtils::get_FunctionType(func);
                if (ftype->m_deftype != ASR::deftypeType::Interface) continue;
                // Only consider module procedure interfaces (m_module=true).
                // Abstract interfaces should not be removed.
                if (!ftype->m_module) continue;
                SymbolTable* parent_symtab = func->m_symtab->parent;
                if (!parent_symtab || !parent_symtab->asr_owner) continue;
                ASR::symbol_t* parent_sym = ASR::down_cast<ASR::symbol_t>(
                    parent_symtab->asr_owner);
                if (!ASR::is_a<ASR::Module_t>(*parent_sym)) continue;
                ASR::Module_t* mod = ASR::down_cast<ASR::Module_t>(parent_sym);
                if (!mod->m_has_submodules) continue;
                std::string func_name = std::string(func->m_name);
                bool impl_processed = false;
                bool impl_declared = false;
                for (auto& top_item : x.m_symtab->get_scope()) {
                    if (!ASR::is_a<ASR::Module_t>(*top_item.second)) continue;
                    ASR::Module_t* sub_mod = ASR::down_cast<ASR::Module_t>(
                        top_item.second);
                    if (!sub_mod->m_parent_module) continue;
                    if (std::string(sub_mod->m_parent_module) !=
                            std::string(mod->m_name)) continue;
                    ASR::symbol_t* impl_sym = sub_mod->m_symtab->resolve_symbol(
                        func_name);
                    if (impl_sym && ASR::is_a<ASR::Function_t>(*impl_sym)) {
                        impl_declared = true;
                        if (proc2newproc.find(impl_sym) != proc2newproc.end()) {
                            impl_processed = true;
                            break;
                        }
                    }
                }
                if (impl_declared && !impl_processed) {
                    iface_to_remove.push_back(kv.first);
                }
            }
            for (ASR::symbol_t* sym : iface_to_remove) {
                ASR::Function_t* new_func = ASR::down_cast<ASR::Function_t>(
                    proc2newproc[sym].first);
                SymbolTable* scope = new_func->m_symtab->parent;
                scope->erase_symbol(std::string(new_func->m_name));
                newprocs.erase(proc2newproc[sym].first);
                proc2newproc.erase(sym);
            }

            // Visit the program
            for (auto &a : x.m_symtab->get_scope()) {
                if( ASR::is_a<ASR::Program_t>(*a.second) ) {
                    this->visit_symbol(*a.second);
                }
            }
        }

        void visit_Program(const ASR::Program_t& x) {
            bfs_visit_SymbolContainingFunctions()
        }

        void visit_Module(const ASR::Module_t& x) {
            // Do not visit intrinsic modules
            if( x.m_intrinsic ) {
                return ;
            }

            bfs_visit_SymbolContainingFunctions()
        }
};

#define edit_symbol_reference(attr) ASR::symbol_t* x_sym = xx.m_##attr;    \
    SymbolTable* x_sym_symtab = ASRUtils::symbol_parent_symtab(x_sym);    \
    if( x_sym_symtab->get_counter() != current_scope->get_counter() &&    \
        !ASRUtils::is_parent(x_sym_symtab, current_scope) ) {    \
        std::string x_sym_name = std::string(ASRUtils::symbol_name(x_sym));    \
        xx.m_##attr = current_scope->resolve_symbol(x_sym_name);    \
        LCOMPILERS_ASSERT(xx.m_##attr != nullptr);    \
    }    \

#define edit_symbol_pointer(attr) ASR::symbol_t* x_sym = x->m_##attr;    \
    SymbolTable* x_sym_symtab = ASRUtils::symbol_parent_symtab(x_sym);    \
    if( x_sym_symtab->get_counter() != current_scope->get_counter() &&    \
        !ASRUtils::is_parent(x_sym_symtab, current_scope) ) {    \
        std::string x_sym_name = std::string(ASRUtils::symbol_name(x_sym));    \
        x->m_##attr = current_scope->resolve_symbol(x_sym_name);    \
        LCOMPILERS_ASSERT(x->m_##attr != nullptr);    \
    }    \

class EditProcedureReplacer: public ASR::BaseExprReplacer<EditProcedureReplacer> {

    public:

    PassArrayByDataProcedureVisitor& v;
    SymbolTable* current_scope;

    EditProcedureReplacer(PassArrayByDataProcedureVisitor& v_):
     v(v_), current_scope(nullptr) {}

    /*
        We need this for the cases where pass array by data is possible for parent function and also
        for the child function. Let's take the following example:
        ```fortran
        subroutine cobyla(x)
            implicit none

            real, intent(inout) :: x(:)
            call evaluate(calcfc_internal)
            contains

            subroutine calcfc_internal(x_internal)
                implicit none
                real, intent(in) :: x_internal(:)
            end subroutine calcfc_internal

            subroutine evaluate(calcfc)
                use, non_intrinsic :: pintrf_mod, only : OBJCON
                implicit none
                procedure(OBJCON) :: calcfc
            end subroutine evaluate

        end subroutine
        ```

        Here, cobyla is parent and calcfc_internal is child. What happens is by `bfs` we first
        create `cobyla_real____0` and add it as a symbol in global scope. Then we visit `cobyla`,
        create `calcfc_internal_real____0` as replacement of `calcfc_internal` and add it as a symbol
        in scope of `cobyla`. Now, we visit `cobyla_real____0` and replace `calcfc_internal` with
        `calcfc_internal_real____0`

        This means both symbols `cobyla` and `cobyla_real____0` have `calcfc_internal_real____0` as a symbol
        but eventually `cobyla` is removed from scope.

        In `proc2newproc` we map `cobyla(1) -> cobyla_real____0(2)` and `calcfc_internal(1.1) -> calcfc_internal_real____0(1.2)`
        and also have `calcfc_internal(2.1) -> calcfc_internal_real____0(2.2)`. Where `(x)` represents symtab counter.

        When it comes to replace `call evaluate(calcfc_internal(1.1))`, it gets replaced with `call evaluate(calcfc_internal_real____0(1.2))`
        which eventually gets deleted. We need to actually replace it with `call evaluate(calcfc_internal_real____0(2.2))`, so what we do is
        we resolve the symbol to the latest symbol in the scope.

        From `calcfc_internal(1.1)`, we get `calcfc_internal_real____0(1.2)` and then we get the parent of `calcfc_internal_real____0(1.2)`,
        i.e. `cobyla(1)`, resolve it to `cobyla_real____0(2)` and then get the symbol `calcfc_internal_real____0(2.2)` from it.
    */
    ASR::symbol_t* resolve_new_proc(ASR::symbol_t* old_sym) {
        ASR::symbol_t* ext_sym = ASRUtils::symbol_get_past_external(old_sym);
        if( v.proc2newproc.find(ext_sym) != v.proc2newproc.end() ) {
            ASR::symbol_t* new_sym = v.proc2newproc[ext_sym].first;
            SymbolTable* new_sym_scope = ASRUtils::symbol_parent_symtab(new_sym);
            ASR::asr_t* new_sym_parent = new_sym_scope->asr_owner;
            if ( ASR::is_a<ASR::symbol_t>(*new_sym_parent) &&
                 current_scope->get_counter() != new_sym_scope->get_counter() &&
                 !ASRUtils::is_parent(new_sym_scope, current_scope) ) {
                ASR::symbol_t* resolved_parent_sym = resolve_new_proc(ASR::down_cast<ASR::symbol_t>(new_sym_parent));
                if ( resolved_parent_sym != nullptr ) {
                    ASR::symbol_t* sym_to_return = ASRUtils::symbol_symtab(resolved_parent_sym)->get_symbol(ASRUtils::symbol_name(new_sym));
                    return sym_to_return ? sym_to_return : new_sym;
                }
            }
            return new_sym;
        }
        return nullptr;
    }

    void replace_Var(ASR::Var_t* x) {
        ASR::symbol_t* x_sym_ = x->m_v;
        bool is_external = ASR::is_a<ASR::ExternalSymbol_t>(*x_sym_);
        if ( v.proc2newproc.find(ASRUtils::symbol_get_past_external(x_sym_)) != v.proc2newproc.end() ) {
            x->m_v = resolve_new_proc(x_sym_);
            if( is_external ) {
                ASR::ExternalSymbol_t* x_sym_ext = ASR::down_cast<ASR::ExternalSymbol_t>(x_sym_);
                std::string new_func_sym_name = current_scope->get_unique_name(ASRUtils::symbol_name(
                    ASRUtils::symbol_get_past_external(x_sym_)));
                 ASR::symbol_t* new_func_sym_ = ASR::down_cast<ASR::symbol_t>(
                    ASR::make_ExternalSymbol_t(v.al, x_sym_->base.loc, current_scope,
                        s2c(v.al, new_func_sym_name), x->m_v, x_sym_ext->m_module_name,
                        x_sym_ext->m_scope_names, x_sym_ext->n_scope_names, ASRUtils::symbol_name(x->m_v),
                        x_sym_ext->m_access));
                v.proc2newproc[x_sym_] = {new_func_sym_, {}};
                current_scope->add_symbol(new_func_sym_name, new_func_sym_);
                x->m_v = new_func_sym_;
            }
            return ;
        }

        edit_symbol_pointer(v)
    }

    void replace_ArrayPhysicalCast(ASR::ArrayPhysicalCast_t* x) {
        ASR::BaseExprReplacer<EditProcedureReplacer>::replace_ArrayPhysicalCast(x);
        // TODO: Allow for DescriptorArray to DescriptorArray physical cast for allocatables
        // later on
        x->m_old = ASRUtils::extract_physical_type(ASRUtils::expr_type(x->m_arg));
        if( (x->m_old == x->m_new &&
             x->m_old != ASR::array_physical_typeType::DescriptorArray) ||
            (x->m_old == x->m_new && x->m_old == ASR::array_physical_typeType::DescriptorArray &&
            (ASR::is_a<ASR::Allocatable_t>(*ASRUtils::expr_type(x->m_arg)) ||
             ASR::is_a<ASR::Pointer_t>(*ASRUtils::expr_type(x->m_arg))) &&
            ASRUtils::extract_n_dims_from_ttype(ASRUtils::expr_type(x->m_arg)) ==
            ASRUtils::extract_n_dims_from_ttype(x->m_type))) {
            *current_expr = x->m_arg;
        } else if (x->m_old == ASR::array_physical_typeType::AssumedRankArray &&
                   !ASRUtils::is_array(x->m_type)) {
            // rank(0): AssumedRankArray → scalar, nothing to update
        } else {
            ASR::Array_t* arr = ASR::down_cast<ASR::Array_t>(ASRUtils::type_get_past_pointer(
                  ASRUtils::type_get_past_allocatable(x->m_type)));
            if (ASRUtils::is_dimension_empty(arr->m_dims, arr->n_dims) && !(x->m_old == ASR::array_physical_typeType::AssumedRankArray)) {
                ASR::Array_t* src_arr = ASR::down_cast<ASR::Array_t>(
                    ASRUtils::type_get_past_allocatable(ASRUtils::type_get_past_pointer(
                        ASRUtils::expr_type(x->m_arg))));
                // Don't replace dims when the target has more dimensions than
                // the source (e.g., assumed-rank target with 15 empty dims).
                if (arr->n_dims <= src_arr->n_dims) {
                    arr->m_dims = ASRUtils::duplicate_dimensions(v.al, src_arr->m_dims, src_arr->n_dims);
                    arr->n_dims = src_arr->n_dims;
                }
            }
        }
    }

    void replace_FunctionCall(ASR::FunctionCall_t* x) {
        edit_symbol_pointer(name)
        ASR::BaseExprReplacer<EditProcedureReplacer>::replace_FunctionCall(x);
    }

};

class EditProcedureVisitor: public ASR::CallReplacerOnExpressionsVisitor<EditProcedureVisitor> {

    public:

    PassArrayByDataProcedureVisitor& v;
    EditProcedureReplacer replacer;

    EditProcedureVisitor(PassArrayByDataProcedureVisitor& v_):
    v(v_), replacer(v) {}

    void call_replacer() {
        replacer.current_expr = current_expr;
        replacer.current_scope = current_scope;
        replacer.replace_expr(*current_expr);
    }

    void visit_BlockCall(const ASR::BlockCall_t& x) {
        ASR::BlockCall_t& xx = const_cast<ASR::BlockCall_t&>(x);
        edit_symbol_reference(m)
        ASR::CallReplacerOnExpressionsVisitor<EditProcedureVisitor>::visit_BlockCall(x);
    }

    void visit_AssociateBlockCall(const ASR::AssociateBlockCall_t& x) {
        ASR::AssociateBlockCall_t& xx = const_cast<ASR::AssociateBlockCall_t&>(x);
        edit_symbol_reference(m)
        ASR::CallReplacerOnExpressionsVisitor<EditProcedureVisitor>::visit_AssociateBlockCall(x);
    }

    void visit_SubroutineCall(const ASR::SubroutineCall_t& x) {
        ASR::SubroutineCall_t& xx = const_cast<ASR::SubroutineCall_t&>(x);
        edit_symbol_reference(name)
        ASR::CallReplacerOnExpressionsVisitor<EditProcedureVisitor>::visit_SubroutineCall(x);
    }

    void update_procedure_variable_type_declarations(SymbolTable* symtab) {
        for (auto it: symtab->get_scope()) {
            if ( ASR::is_a<ASR::Variable_t>(*it.second) &&
                ASR::down_cast<ASR::Variable_t>(it.second)->m_type_declaration ) {
                ASR::Variable_t* var = ASR::down_cast<ASR::Variable_t>(it.second);
                ASR::symbol_t* resolved_type_dec = nullptr;
                if ( v.proc2newproc.find(var->m_type_declaration) != v.proc2newproc.end() ) {
                    resolved_type_dec = v.proc2newproc[var->m_type_declaration].first;
                } else if ( v.proc2newproc.find(ASRUtils::symbol_get_past_external(var->m_type_declaration)) != v.proc2newproc.end() ) {
                    resolved_type_dec = v.proc2newproc[ASRUtils::symbol_get_past_external(var->m_type_declaration)].first;
                }
                if ( resolved_type_dec ) {
                    ASR::Function_t* fn = ASR::down_cast<ASR::Function_t>(resolved_type_dec);
                    var->m_type_declaration = resolved_type_dec;
                    ASR::ttype_t* new_type = fn->m_function_signature;
                    if (ASR::is_a<ASR::Pointer_t>(*var->m_type)) {
                        new_type = ASRUtils::TYPE(ASR::make_Pointer_t(v.al, var->base.base.loc, new_type));
                    }
                    var->m_type = new_type;
                }
            }
        }
    }

    void visit_Module(const ASR::Module_t& x) {
        update_procedure_variable_type_declarations(x.m_symtab);
        ASR::CallReplacerOnExpressionsVisitor<EditProcedureVisitor>::visit_Module(x);
    }

    void visit_Program(const ASR::Program_t& x) {
        update_procedure_variable_type_declarations(x.m_symtab);
        ASR::CallReplacerOnExpressionsVisitor<EditProcedureVisitor>::visit_Program(x);
    }

    void visit_Function(const ASR::Function_t& x) {
        update_procedure_variable_type_declarations(x.m_symtab);
        ASR::CallReplacerOnExpressionsVisitor<EditProcedureVisitor>::visit_Function(x);
    }

};

/*
    The following visitor replaces procedure calls with arrays as arguments
    to procedure calls having dimensional information passed as arguments. See example below,

        call f1(array1, array2)
        sum = f(array) + g(array)

    gets converted to,

        call f1_array1_array2(array1, m1, n1, array2, m2, n2)
        sum = f_array(array, m, n) + g_array(array, m, n)

    As can be seen dimensional information, m1, n1 is passed along
    with array1 and similarly m2, n2 is passed along with array2.
 */
class EditProcedureCallsVisitor : public ASR::ASRPassBaseWalkVisitor<EditProcedureCallsVisitor>
{
    private:

        Allocator& al;
        PassArrayByDataProcedureVisitor& v;
        std::set<ASR::symbol_t*>& not_to_be_erased;
        const LCompilers::PassOptions& pass_options;

    public:

        int get_index_kind() const {
            return pass_options.descriptor_index_64 ? 8 : 4;
        }

        EditProcedureCallsVisitor(Allocator& al_,
            PassArrayByDataProcedureVisitor& v_,
            std::set<ASR::symbol_t*>& not_to_be_erased_,
            const LCompilers::PassOptions& pass_options_):
        al(al_), v(v_), not_to_be_erased(not_to_be_erased_), pass_options(pass_options_) {}

        // this is exactly the same as the one in EditProcedureReplacer
        ASR::symbol_t* resolve_new_proc(ASR::symbol_t* old_sym) {
            ASR::symbol_t* ext_sym = ASRUtils::symbol_get_past_external(old_sym);
            if( v.proc2newproc.find(ext_sym) != v.proc2newproc.end() ) {
                ASR::symbol_t* new_sym = v.proc2newproc[ext_sym].first;
                SymbolTable* new_sym_scope = ASRUtils::symbol_parent_symtab(new_sym);
                ASR::asr_t* new_sym_parent = new_sym_scope->asr_owner;
                if ( ASR::is_a<ASR::symbol_t>(*new_sym_parent) &&
                        current_scope->get_counter() != new_sym_scope->get_counter() &&
                        !ASRUtils::is_parent(new_sym_scope, current_scope) ) {
                    ASR::symbol_t* resolved_parent_sym = resolve_new_proc(ASR::down_cast<ASR::symbol_t>(new_sym_parent));
                    if ( resolved_parent_sym != nullptr ) {
                        ASR::symbol_t* sym_to_return = ASRUtils::symbol_symtab(resolved_parent_sym)->get_symbol(ASRUtils::symbol_name(new_sym));
                        return sym_to_return ? sym_to_return : new_sym;
                    }
                }
                return new_sym;
            }
            return nullptr;
        }

        template <typename T>
        void update_args_for_pass_arr_by_data_funcs_passed_as_callback(const T& x) {
            bool args_updated = false;
            Vec<ASR::call_arg_t> new_args;
            new_args.reserve(al, x.n_args);
            for ( size_t i = 0; i < x.n_args; i++ ) {
                ASR::call_arg_t arg = x.m_args[i];
                ASR::expr_t* expr = arg.m_value;
                if (expr) {
                    if (ASR::is_a<ASR::Var_t>(*expr)) {
                        ASR::Var_t* var = ASR::down_cast<ASR::Var_t>(expr);
                        ASR::symbol_t* sym = var->m_v;
                        if ( v.proc2newproc.find(sym) != v.proc2newproc.end() ) {
                            ASR::symbol_t* new_var_sym = resolve_new_proc(sym);
                            ASR::expr_t* new_var = ASRUtils::EXPR(ASR::make_Var_t(al, var->base.base.loc, new_var_sym));
                            {
                                // update exisiting arg
                                arg.m_value = new_var;
                                arg.loc = arg.loc;
                            }
                            args_updated = true;
                        }
                    }
                }
                new_args.push_back(al, arg);
            }
            if (args_updated) {
                T&xx = const_cast<T&>(x);
                xx.m_args = new_args.p;
                xx.n_args = new_args.size();
            }
        }

        inline void get_dimensions(ASR::expr_t* array, Vec<ASR::expr_t*>& dims,
                                        Allocator& al_) {
            int index_kind = get_index_kind();
            ASR::ttype_t* array_type = ASRUtils::expr_type(array);
            ASR::dimension_t* compile_time_dims = nullptr;
            int n_dims = ASRUtils::extract_dimensions_from_ttype(array_type, compile_time_dims);
            if( n_dims == 0 ) {
                ASR::ttype_t* scalar_type = ASRUtils::type_get_past_allocatable_pointer(array_type);
                if( scalar_type && ASR::is_a<ASR::String_t>(*scalar_type) ) {
                    ASRUtils::ASRBuilder builder(al_, array->base.loc);
                    ASR::expr_t* length = builder.StringLen(array);
                    dims.push_back(al_, length);
                    return;
                }
            }
            for( int i = 0; i < n_dims; i++ ) {
                ASR::expr_t* length = compile_time_dims[i].m_length;
                if( length == nullptr ) {
                    if (ASRUtils::is_allocatable(array_type)) {
                        length = ASRUtils::get_size(array, i + 1, al_);
                    } else {
                        // Pass the extent (ubound - lbound + 1), not the
                        // upper bound. The callee stores this value as the
                        // dimension's extent in its descriptor; using ubound
                        // would corrupt the upper bound for arrays with
                        // non-default lower bounds.
                        ASR::expr_t* ub = PassUtils::get_bound(array, i + 1, "ubound", al_, index_kind);
                        ASR::expr_t* lb = PassUtils::get_bound(array, i + 1, "lbound", al_, index_kind);
                        ASR::ttype_t* int_t = ASRUtils::TYPE(ASR::make_Integer_t(al_, array->base.loc, index_kind));
                        ASR::expr_t* one = ASRUtils::EXPR(ASR::make_IntegerConstant_t(al_, array->base.loc, 1, int_t));
                        ASR::expr_t* ub_minus_lb = ASRUtils::EXPR(ASR::make_IntegerBinOp_t(al_, array->base.loc,
                            ub, ASR::binopType::Sub, lb, int_t, nullptr));
                        length = ASRUtils::EXPR(ASR::make_IntegerBinOp_t(al_, array->base.loc,
                            ub_minus_lb, ASR::binopType::Add, one, int_t, nullptr));
                    }
                }
                if ( ASRUtils::is_integer(*ASRUtils::expr_type(length)) ) {
                    ASR::Integer_t* int_type = ASR::down_cast<ASR::Integer_t>(ASRUtils::type_get_past_array(
                                                ASRUtils::type_get_past_allocatable_pointer(ASRUtils::expr_type(length))));
                    if (int_type->m_kind != index_kind) {
                        // Cast to target index kind
                        length = ASRUtils::EXPR(ASRUtils::make_Cast_t_value(al_, length->base.loc, length, ASR::cast_kindType::IntegerToInteger,
                            ASRUtils::TYPE(ASR::make_Integer_t(al_, length->base.loc, index_kind))));
                    }

                }
                dims.push_back(al_, length);
            }
        }

        static inline int64_t get_expected_n_dims(ASR::symbol_t* subrout_sym, size_t arg_idx) {
            if( !ASR::is_a<ASR::Function_t>(*subrout_sym) ) {
                return -1;
            }
            ASR::Function_t* subrout = ASR::down_cast<ASR::Function_t>(subrout_sym);
            if( arg_idx >= subrout->n_args ) {
                return -1;
            }
            if( !ASR::is_a<ASR::Var_t>(*subrout->m_args[arg_idx]) ) {
                return -1;
            }
            ASR::Variable_t* arg = ASRUtils::EXPR2VAR(subrout->m_args[arg_idx]);
            ASR::dimension_t* dims = nullptr;
            return ASRUtils::extract_dimensions_from_ttype(arg->m_type, dims);
        }

        ASR::expr_t* maybe_cast_class_arg_to_struct(ASR::symbol_t* subrout_sym,
            size_t arg_idx, ASR::expr_t* arg_expr) {
            if( arg_expr == nullptr || !ASR::is_a<ASR::Function_t>(*subrout_sym) ) {
                return arg_expr;
            }
            ASR::Function_t* subrout = ASR::down_cast<ASR::Function_t>(subrout_sym);
            if( arg_idx >= subrout->n_args || !ASR::is_a<ASR::Var_t>(*subrout->m_args[arg_idx]) ) {
                return arg_expr;
            }

            ASR::expr_t* formal_arg = subrout->m_args[arg_idx];
            ASR::ttype_t* formal_arg_full_type = ASRUtils::expr_type(formal_arg);
            if (ASRUtils::is_allocatable(formal_arg_full_type) ||
                ASRUtils::is_pointer(formal_arg_full_type)) {
                return arg_expr;
            }
            if (!ASR::is_a<ASR::ArrayItem_t>(*arg_expr)) {
                return arg_expr;
            }
            ASR::ttype_t* actual_type = ASRUtils::type_get_past_allocatable_pointer(
                ASRUtils::expr_type(arg_expr));
            ASR::ttype_t* formal_type = ASRUtils::type_get_past_allocatable_pointer(
                ASRUtils::expr_type(formal_arg));

            if( !actual_type || !formal_type ||
                !ASR::is_a<ASR::StructType_t>(*actual_type) ||
                !ASR::is_a<ASR::StructType_t>(*formal_type) ) {
                return arg_expr;
            }

            if( !ASRUtils::is_class_type(actual_type) || ASRUtils::is_class_type(formal_type) ) {
                return arg_expr;
            }

            ASR::symbol_t* actual_struct_sym = ASRUtils::symbol_get_past_external(
                ASRUtils::get_struct_sym_from_struct_expr(arg_expr));
            ASR::symbol_t* formal_struct_sym = ASRUtils::symbol_get_past_external(
                ASRUtils::get_struct_sym_from_struct_expr(formal_arg));
            if( !actual_struct_sym || !formal_struct_sym ||
                !ASR::is_a<ASR::Struct_t>(*actual_struct_sym) ||
                !ASR::is_a<ASR::Struct_t>(*formal_struct_sym) ) {
                return arg_expr;
            }

            if( actual_struct_sym != formal_struct_sym ) {
                return arg_expr;
            }

            return ASRUtils::EXPR(ASR::make_Cast_t(al, arg_expr->base.loc, arg_expr,
                ASR::cast_kindType::ClassToStruct,
                ASRUtils::duplicate_type(al, ASRUtils::expr_type(formal_arg)), nullptr, nullptr));
        }

        Vec<ASR::call_arg_t> construct_new_args(ASR::symbol_t* subrout_sym,
            size_t n_args, ASR::call_arg_t* orig_args, std::vector<size_t>& indices) {
            Vec<ASR::call_arg_t> new_args;
            new_args.reserve(al, n_args);
            for( size_t i = 0; i < n_args; i++ ) {
                if (orig_args[i].m_value == nullptr) {
                    new_args.push_back(al, orig_args[i]);
                    continue;
                } else if (std::find(indices.begin(), indices.end(), i) == indices.end()) {
                    ASR::expr_t* expr = orig_args[i].m_value;
                    if (ASR::is_a<ASR::Var_t>(*expr)) {
                        ASR::Var_t* var = ASR::down_cast<ASR::Var_t>(expr);
                        ASR::symbol_t* sym = var->m_v;
                        if ( v.proc2newproc.find(sym) != v.proc2newproc.end() ) {
                            ASR::symbol_t* new_var_sym = v.proc2newproc[sym].first;
                            ASR::expr_t* new_var = ASRUtils::EXPR(ASR::make_Var_t(al, var->base.base.loc, new_var_sym));
                            orig_args[i].m_value = new_var;
                        }
                    }
                    orig_args[i].m_value = maybe_cast_class_arg_to_struct(
                        subrout_sym, i, orig_args[i].m_value);
                    // The function parameter expects PointerArray but the actual
                    // call arg may be DescriptorArray (e.g. a temp created by
                    // subroutine_from_function). Add ArrayPhysicalCast.
                    ASR::ttype_t* arg_type = ASRUtils::expr_type(orig_args[i].m_value);
                    if (ASRUtils::is_array(arg_type)) {
                        ASR::Array_t* array_t = ASR::down_cast<ASR::Array_t>(
                            ASRUtils::type_get_past_allocatable(
                                ASRUtils::type_get_past_pointer(arg_type)));
                        if (array_t->m_physical_type == ASR::array_physical_typeType::DescriptorArray) {
                            ASR::FunctionType_t* ft = ASRUtils::get_FunctionType(subrout_sym);
                            size_t param_idx = i;
                            if (param_idx < ft->n_arg_types &&
                                    ASRUtils::is_array(ft->m_arg_types[param_idx])) {
                                ASR::Array_t* param_array = ASR::down_cast<ASR::Array_t>(
                                    ASRUtils::type_get_past_allocatable(
                                        ASRUtils::type_get_past_pointer(ft->m_arg_types[param_idx])));
                                if (param_array->m_physical_type == ASR::array_physical_typeType::PointerArray) {
                                    ASR::expr_t* physical_cast = ASRUtils::EXPR(
                                        ASRUtils::make_ArrayPhysicalCast_t_util(
                                            al, orig_args[i].m_value->base.loc,
                                            orig_args[i].m_value, array_t->m_physical_type,
                                            ASR::array_physical_typeType::PointerArray,
                                            ASRUtils::duplicate_type(al, arg_type, nullptr,
                                                ASR::array_physical_typeType::PointerArray, true),
                                            nullptr));
                                    orig_args[i].m_value = physical_cast;
                                }
                            }
                        }
                    }
                    new_args.push_back(al, orig_args[i]);
                    continue;
                }

                ASR::expr_t* orig_arg_i = orig_args[i].m_value;
                ASR::ttype_t* orig_arg_type = ASRUtils::expr_type(orig_arg_i);
                if( ASRUtils::is_array(orig_arg_type) ) {
                    ASR::Array_t* array_t = ASR::down_cast<ASR::Array_t>(
                        ASRUtils::type_get_past_allocatable(ASRUtils::type_get_past_pointer(orig_arg_type)));
                    if( array_t->m_physical_type != ASR::array_physical_typeType::PointerArray ) {
                        ASR::expr_t* physical_cast = ASRUtils::EXPR(ASRUtils::make_ArrayPhysicalCast_t_util(
                            al, orig_arg_i->base.loc, orig_arg_i, array_t->m_physical_type,
                            ASR::array_physical_typeType::PointerArray, ASRUtils::duplicate_type(al, orig_arg_type,
                            nullptr, ASR::array_physical_typeType::PointerArray, true), nullptr));
                        ASR::call_arg_t physical_cast_arg;
                        physical_cast_arg.loc = orig_arg_i->base.loc;
                        physical_cast_arg.m_value = physical_cast;
                        new_args.push_back(al, physical_cast_arg);
                    } else {
                        new_args.push_back(al, orig_args[i]);
                    }
                } else {
                    new_args.push_back(al, orig_args[i]);
                }

                Vec<ASR::expr_t*> actual_dim_vars;
                actual_dim_vars.reserve(al, 2);
                get_dimensions(orig_arg_i, actual_dim_vars, al);

                int64_t expected_n_dims = get_expected_n_dims(subrout_sym, i);
                Vec<ASR::expr_t*> dim_vars;
                dim_vars.reserve(al, actual_dim_vars.size());

                if( expected_n_dims <= 0 ||
                    (size_t) expected_n_dims == actual_dim_vars.size() ) {
                    for( size_t j = 0; j < actual_dim_vars.size(); j++ ) {
                        dim_vars.push_back(al, actual_dim_vars[j]);
                    }
                } else {
                    ASRUtils::ASRBuilder builder(al, orig_arg_i->base.loc);
                    if( (size_t) expected_n_dims < actual_dim_vars.size() ) {
                        for( int64_t j = 0; j < expected_n_dims - 1; j++ ) {
                            dim_vars.push_back(al, actual_dim_vars[j]);
                        }
                        ASR::expr_t* tail_prod = actual_dim_vars[expected_n_dims - 1];
                        for( size_t j = (size_t) expected_n_dims; j < actual_dim_vars.size(); j++ ) {
                            tail_prod = builder.Mul(tail_prod, actual_dim_vars[j]);
                        }
                        dim_vars.push_back(al, tail_prod);
                    } else {
                        for( size_t j = 0; j < actual_dim_vars.size(); j++ ) {
                            dim_vars.push_back(al, actual_dim_vars[j]);
                        }
                        int index_kind = get_index_kind();
                        for( int64_t j = (int64_t) actual_dim_vars.size(); j < expected_n_dims; j++ ) {
                            dim_vars.push_back(al, make_ConstantWithKind(make_IntegerConstant_t, make_Integer_t, 1, index_kind, orig_arg_i->base.loc));
                        }
                    }
                }

                for( size_t j = 0; j < dim_vars.size(); j++ ) {
                    ASR::call_arg_t dim_var;
                    dim_var.loc = dim_vars[j]->base.loc;
                    dim_var.m_value = dim_vars[j];
                    new_args.push_back(al, dim_var);
                }
            }
            return new_args;
        }

        bool can_edit_call(ASR::call_arg_t* args, size_t n_args) {
            for ( size_t i = 0; i < n_args; i++ ) {
                if( args[i].m_value &&
                    ASRUtils::expr_type(args[i].m_value) &&
                    ASR::is_a<ASR::Pointer_t>(*
                        ASRUtils::expr_type(args[i].m_value)) ) {
                    return false;
                }
            }
            return true;
        }
        
        static bool is_struct_method_declaration(ASR::symbol_t* const sym){
            return ASR::is_a<ASR::StructMethodDeclaration_t>(*ASRUtils::symbol_get_past_external(sym));
        }

        template <typename T>
        void visit_Call(const T& x) {
            T& xx = const_cast<T&>(x);
            ASR::symbol_t* subrout_sym = x.m_name;
            bool is_external = ASR::is_a<ASR::ExternalSymbol_t>(*subrout_sym);
            subrout_sym = ASRUtils::symbol_get_past_StructMethodDeclaration(
                            ASRUtils::symbol_get_past_external(subrout_sym));
            if(ASR::is_a<ASR::Variable_t>(*ASRUtils::symbol_get_past_external(x.m_name))){
                // Case: procedure(cb) :: call_back (Here call_back is variable of type cb which is a function)
                ASR::Variable_t* variable = ASR::down_cast<ASR::Variable_t>(ASRUtils::symbol_get_past_external(x.m_name));
                ASR::symbol_t* type_dec = variable->m_type_declaration;
                subrout_sym = ASRUtils::symbol_get_past_external(type_dec);

                // check if subrout_sym is present as value in proc2newproc
                bool is_present = false;
                std::vector<size_t> present_indices;
                ASR::symbol_t* original_subrout_sym = nullptr;
                for ( auto it: v.proc2newproc ) {
                    if (it.second.first == subrout_sym) {
                        is_present = true;
                        present_indices = it.second.second;
                        original_subrout_sym = it.first;
                        break;
                    }
                }

                if ( v.proc2newproc.find(subrout_sym) != v.proc2newproc.end()) {
                    ASR::symbol_t* new_x_name = nullptr;
                    if (is_external && (v.proc2newproc.find(x.m_name) != v.proc2newproc.end())) {
                        new_x_name = v.proc2newproc[x.m_name].first;
                    } else {
                        new_x_name = resolve_new_proc(x.m_name);
                        // If the call target was an ExternalSymbol and
                        // resolve_new_proc returned a symbol outside the
                        // current scope (e.g. a new Variable inside a
                        // struct's symtab), wrap it in an ExternalSymbol
                        // so that m_name stays within the current scope.
                        if (is_external && new_x_name != nullptr &&
                            ASRUtils::symbol_parent_symtab(new_x_name)->get_counter() !=
                                current_scope->get_counter()) {
                            ASR::ExternalSymbol_t* orig_ext =
                                ASR::down_cast<ASR::ExternalSymbol_t>(x.m_name);
                            std::string new_ext_name = current_scope->get_unique_name(
                                ASRUtils::symbol_name(new_x_name));
                            ASR::symbol_t* new_ext = ASR::down_cast<ASR::symbol_t>(
                                ASR::make_ExternalSymbol_t(al, x.m_name->base.loc,
                                    current_scope, s2c(al, new_ext_name), new_x_name,
                                    orig_ext->m_module_name,
                                    orig_ext->m_scope_names, orig_ext->n_scope_names,
                                    ASRUtils::symbol_name(new_x_name),
                                    orig_ext->m_access));
                            current_scope->add_symbol(new_ext_name, new_ext);
                            new_x_name = new_ext;
                        }
                    }
                    // If the variable hasn't been registered yet (e.g. due to
                    // alphabetical visit order where an AssociateBlock or Block
                    // containing the call is visited before this variable),
                    // process it now so the call can be properly updated.
                    if ( new_x_name == nullptr && !is_external &&
                         v.proc2newproc.find((ASR::symbol_t*)variable) == v.proc2newproc.end() ) {
                        visit_Variable(*variable);
                        new_x_name = resolve_new_proc(x.m_name);
                    }
                    if ( new_x_name != nullptr ) {
                        ASR::Function_t* new_func = ASR::down_cast<ASR::Function_t>(resolve_new_proc(subrout_sym));
                        ASR::Variable_t* call_var = ASR::down_cast<ASR::Variable_t>(ASRUtils::symbol_get_past_external(x.m_name));
                        ASR::ttype_t* new_type = new_func->m_function_signature;
                        if (ASR::is_a<ASR::Pointer_t>(*call_var->m_type)) {
                            new_type = ASRUtils::TYPE(ASR::make_Pointer_t(v.al, call_var->base.base.loc, new_type));
                        }
                        call_var->m_type = new_type;
                        xx.m_name = new_x_name;
                        xx.m_original_name = new_x_name;
                        std::vector<size_t>& indices = v.proc2newproc[subrout_sym].second;
                        // Self is now explicitly in call args, so no offset needed.
                        Vec<ASR::call_arg_t> new_args = construct_new_args(subrout_sym, x.n_args, x.m_args, indices);
                        xx.m_args = new_args.p;
                        xx.n_args = new_args.size();
                        return;
                    } else if ( new_x_name == nullptr ) {
                        std::vector<size_t>& indices = v.proc2newproc[subrout_sym].second;
                        Vec<ASR::call_arg_t> new_args = construct_new_args(subrout_sym, x.n_args, x.m_args, indices);
                        xx.m_args = new_args.p;
                        xx.n_args = new_args.size();
                        return;
                    }
                } else if ( is_present ) {
                    Vec<ASR::call_arg_t> new_args = construct_new_args(original_subrout_sym, x.n_args, x.m_args, present_indices);
                    xx.m_args = new_args.p;
                    xx.n_args = new_args.size();
                    return;
                }
            }

            if( !can_edit_call(x.m_args, x.n_args)
                    && !is_struct_method_declaration(x.m_name) ) {
                not_to_be_erased.insert(subrout_sym);
                return ;
            }
            if( v.proc2newproc.find(subrout_sym) == v.proc2newproc.end() ) {
                update_args_for_pass_arr_by_data_funcs_passed_as_callback(x);
                return;
            }

            // Don't transform calls dispatched through StructMethodDeclaration
            // (type-bound procedures). These may go through the vtable, which
            // is linkonce_odr and must be identical across all compilation
            // units. Since ____N versions are only created when function bodies
            // are available, the vtable would be inconsistent between units
            // that define vs. merely use the type.
            if (is_struct_method_declaration(x.m_name)) {
                not_to_be_erased.insert(subrout_sym);
                return;
            }

            ASR::symbol_t* new_func_sym = resolve_new_proc(subrout_sym);
            std::vector<size_t>& indices = v.proc2newproc[subrout_sym].second;
            Vec<ASR::call_arg_t> new_args = construct_new_args(subrout_sym, x.n_args, x.m_args, indices);

            {
                ASR::Function_t* new_func_ = ASR::down_cast<ASR::Function_t>(new_func_sym);
                size_t min_args = 0, max_args = 0;
                for( size_t i = 0; i < new_func_->n_args; i++ ) {
                    ASR::Var_t* arg = ASR::down_cast<ASR::Var_t>(new_func_->m_args[i]);
                    if( ASR::is_a<ASR::Variable_t>(*arg->m_v) &&
                        ASR::down_cast<ASR::Variable_t>(arg->m_v)->m_presence
                            == ASR::presenceType::Optional ) {
                        max_args += 1;
                    } else {
                        min_args += 1;
                        max_args += 1;
                    }
                }
                if( !(min_args <= new_args.size() &&
                    new_args.size() <= max_args) ) {
                    throw LCompilersException("Number of arguments in the new function call " +
                        std::string(ASRUtils::symbol_name(subrout_sym)) + " doesn't satisfy "
                        "min_args <= new_args.size() <= max_args, " + std::to_string(min_args) + " <= " +
                        std::to_string(new_args.size()) + " <= " + std::to_string(max_args));
                }
            }
            ASR::symbol_t* new_func_sym_ = new_func_sym;
            // Note: smd.m_proc is intentionally NOT updated (see
            // visit_StructMethodDeclaration). Calls through SMDs are skipped
            // earlier in this function so this code path is only reached for
            // non-SMD calls.
            if( is_external && !is_struct_method_declaration(x.m_name) ) { // Redirect ExternalSymbol to new fn symbol.
                ASR::ExternalSymbol_t* func_ext_sym = ASR::down_cast<ASR::ExternalSymbol_t>(x.m_name);
                std::string new_func_sym_name = std::string(ASRUtils::symbol_name(new_func_sym));
                ASR::symbol_t* existing_sym = current_scope->resolve_symbol(new_func_sym_name);
                if( existing_sym != nullptr ) {
                    ASR::symbol_t* existing_target = ASRUtils::symbol_get_past_external(existing_sym);
                    if( existing_target == new_func_sym ) {
                        new_func_sym_ = existing_sym;
                    } else {
                        // Name is occupied by an unrelated symbol (possibly in a
                        // parent scope). Create a unique alias for this external
                        // symbol in the current scope.
                        new_func_sym_name = current_scope->get_unique_name(new_func_sym_name, false);
                        existing_sym = nullptr;
                    }
                }
                if( existing_sym == nullptr ) {
                    char* new_func_sym_name_c = s2c(al, new_func_sym_name);
                    if ( ASR::is_a<ASR::Variable_t>(*ASRUtils::symbol_get_past_external(func_ext_sym->m_external)) &&
                         ASR::down_cast<ASR::Variable_t>(ASRUtils::symbol_get_past_external(func_ext_sym->m_external))->m_type_declaration ) {
                        ASR::Variable_t* var = ASR::down_cast<ASR::Variable_t>(ASRUtils::symbol_get_past_external(func_ext_sym->m_external));
                        ASR::symbol_t* type_dec_sym = current_scope->resolve_symbol(ASRUtils::symbol_name(var->m_type_declaration));
                        std::string module_name = func_ext_sym->m_module_name;

                        if ( type_dec_sym && ASR::is_a<ASR::ExternalSymbol_t>(*type_dec_sym) ) {
                            module_name = ASR::down_cast<ASR::ExternalSymbol_t>(type_dec_sym)->m_module_name;
                        }
                        new_func_sym_ = ASR::down_cast<ASR::symbol_t>(
                            ASR::make_ExternalSymbol_t(al, x.m_name->base.loc, func_ext_sym->m_parent_symtab,
                                new_func_sym_name_c, new_func_sym, s2c(al, module_name),
                                func_ext_sym->m_scope_names, func_ext_sym->n_scope_names,
                                ASRUtils::symbol_name(new_func_sym),
                                func_ext_sym->m_access));
                    } else {
                        new_func_sym_ = ASR::down_cast<ASR::symbol_t>(
                            ASR::make_ExternalSymbol_t(al, x.m_name->base.loc, func_ext_sym->m_parent_symtab,
                                new_func_sym_name_c, new_func_sym, func_ext_sym->m_module_name,
                                func_ext_sym->m_scope_names, func_ext_sym->n_scope_names,
                                ASRUtils::symbol_name(new_func_sym),
                                func_ext_sym->m_access));
                    }

                    func_ext_sym->m_parent_symtab->add_symbol(new_func_sym_name, new_func_sym_);
                }
            }
            if(!ASR::is_a<ASR::Variable_t>(*x.m_name) && !is_struct_method_declaration(x.m_name)){
                xx.m_name = new_func_sym_;
                xx.m_original_name = new_func_sym_;
            } else if(v.proc2newproc.find(x.m_name) != v.proc2newproc.end()){
                xx.m_name = resolve_new_proc(x.m_name);
                xx.m_original_name = resolve_new_proc(x.m_name);
            }
            xx.m_args = new_args.p;
            xx.n_args = new_args.size();
        }

        void visit_TranslationUnit(const ASR::TranslationUnit_t &x) {
            SymbolTable* current_scope_copy = current_scope;
            current_scope = x.m_symtab;
            // Visit modules in dependency order so that struct member
            // transformations in a dependency are visible when processing
            // modules that use those structs (e.g. StructInstanceMember
            // references).
            std::vector<std::string> mod_order
                = ASRUtils::determine_module_dependencies(x);
            for (auto &name : mod_order) {
                ASR::symbol_t *sym = x.m_symtab->get_symbol(name);
                if (sym && ASR::is_a<ASR::Module_t>(*sym)) {
                    this->visit_symbol(*sym);
                }
            }
            for (auto &a : x.m_symtab->get_scope()) {
                if (!ASR::is_a<ASR::Module_t>(*a.second)) {
                    this->visit_symbol(*a.second);
                }
            }
            current_scope = current_scope_copy;
        }

        void visit_Program(const ASR::Program_t &x) {
            ASR::Program_t& xx = const_cast<ASR::Program_t&>(x);
            SymbolTable* current_scope_copy = current_scope;
            current_scope = x.m_symtab;
            for (auto &a : x.m_symtab->get_scope()) {
                if(!ASR::is_a<ASR::Function_t>(*a.second)){
                    this->visit_symbol(*a.second);
                }
            }
            for (auto &a : x.m_symtab->get_scope()) {
                if(ASR::is_a<ASR::Function_t>(*a.second)){
                    this->visit_symbol(*a.second);
                }
            }
            this->transform_stmts(xx.m_body, xx.n_body);
            current_scope = current_scope_copy;
        }

        void visit_Module(const ASR::Module_t &x) {
            SymbolTable* current_scope_copy = current_scope;
            current_scope = x.m_symtab;
            for (auto &a : x.m_symtab->get_scope()) {
                if(!ASR::is_a<ASR::Function_t>(*a.second)){
                    this->visit_symbol(*a.second);
                }
            }
            for (auto &a : x.m_symtab->get_scope()) {
                if(ASR::is_a<ASR::Function_t>(*a.second)){
                    this->visit_symbol(*a.second);
                }
            }
            current_scope = current_scope_copy;
        }

        void visit_SubroutineCall(const ASR::SubroutineCall_t& x) {
            ASR::ASRPassBaseWalkVisitor<EditProcedureCallsVisitor>::visit_SubroutineCall(x);
            visit_Call(x);
        }

        void visit_FunctionCall(const ASR::FunctionCall_t& x) {
            ASR::ASRPassBaseWalkVisitor<EditProcedureCallsVisitor>::visit_FunctionCall(x);
            visit_Call(x);
        }

        void visit_Variable(const ASR::Variable_t &x) {
            if (v.proc2newproc.find((ASR::symbol_t*) &x) != v.proc2newproc.end()){
                return;
            }
            // Case: procedure(cb) :: call_back (Here call_back is variable of type cb which is a function)
            ASR::symbol_t* type_dec = x.m_type_declaration;
            if (v.proc2newproc.find(ASRUtils::symbol_get_past_external(type_dec)) != v.proc2newproc.end() &&
                    v.proc2newproc.find(type_dec) == v.proc2newproc.end()){
                ASR::symbol_t* new_func = resolve_new_proc(ASRUtils::symbol_get_past_external(type_dec));
                ASR::ExternalSymbol_t* x_sym_ext = ASR::down_cast<ASR::ExternalSymbol_t>(type_dec);
                std::string new_func_sym_name = x_sym_ext->m_parent_symtab->get_unique_name(ASRUtils::symbol_name(
                    ASRUtils::symbol_get_past_external(type_dec)));
                ASR::symbol_t* new_func_sym_ = ASR::down_cast<ASR::symbol_t>(
                    ASR::make_ExternalSymbol_t(v.al, type_dec->base.loc, x_sym_ext->m_parent_symtab,
                        s2c(v.al, new_func_sym_name), new_func, x_sym_ext->m_module_name,
                        x_sym_ext->m_scope_names, x_sym_ext->n_scope_names, ASRUtils::symbol_name(new_func),
                        x_sym_ext->m_access));
                v.proc2newproc[type_dec] = {new_func_sym_, {}};
                x_sym_ext->m_parent_symtab->add_symbol(new_func_sym_name, new_func_sym_);
            }
            if(type_dec && v.proc2newproc.find(type_dec) != v.proc2newproc.end() &&
                ASR::is_a<ASR::Function_t>(*ASRUtils::symbol_get_past_external(type_dec))){
                ASR::symbol_t* new_sym = resolve_new_proc(type_dec);
                if ( new_sym == nullptr ) {
                    return;
                }
                ASR::expr_t* sym_val = x.m_symbolic_value;
                ASR::expr_t* m_val = x.m_value;
                ASR::Function_t * subrout = ASR::down_cast<ASR::Function_t>(ASRUtils::symbol_get_past_external(new_sym));
                if (x.m_symbolic_value && ASR::is_a<ASR::PointerNullConstant_t>(*x.m_symbolic_value)) {
                    ASR::PointerNullConstant_t* pnc = ASR::down_cast<ASR::PointerNullConstant_t>(x.m_symbolic_value);
                    pnc->m_type = subrout->m_function_signature;
                    sym_val = (ASR::expr_t*) pnc;
                }
                if (x.m_value && ASR::is_a<ASR::PointerNullConstant_t>(*x.m_value)) {
                    ASR::PointerNullConstant_t* pnc = ASR::down_cast<ASR::PointerNullConstant_t>(x.m_value);
                    pnc->m_type = subrout->m_function_signature;
                    m_val = (ASR::expr_t*) pnc;
                }
                std::string new_sym_name = x.m_parent_symtab->get_unique_name(x.m_name);
                ASR::ttype_t* new_var_type = subrout->m_function_signature;
                if (ASR::is_a<ASR::Pointer_t>(*x.m_type)) {
                    new_var_type = ASRUtils::TYPE(ASR::make_Pointer_t(v.al, x.base.base.loc, new_var_type));
                }
                ASR::symbol_t* new_func_sym_ = ASR::down_cast<ASR::symbol_t>(
                    ASRUtils::make_Variable_t_util(v.al, x.base.base.loc, x.m_parent_symtab, s2c(v.al, new_sym_name),
                        x.m_dependencies, x.n_dependencies, x.m_intent,
                        sym_val, m_val, x.m_storage, new_var_type,
                        new_sym, x.m_abi, x.m_access, x.m_presence, x.m_value_attr,
                        x.m_target_attr, x.m_contiguous_attr, x.m_bindc_name,
                        x.m_is_volatile, x.m_is_protected, x.m_pass_attr, x.m_self_argument));
                v.proc2newproc[(ASR::symbol_t *) &x] = {new_func_sym_, {}};
                x.m_parent_symtab->add_symbol(new_sym_name, new_func_sym_);
                not_to_be_erased.insert(new_func_sym_);
            }
            ASR::ASRPassBaseWalkVisitor<EditProcedureCallsVisitor>::visit_Variable(x);
        }

        void visit_StructInstanceMember(const ASR::StructInstanceMember_t &x) {
            //Case: prob % calfun => temp_calfun (where calfun is procedure variable)
            ASR::ASRPassBaseWalkVisitor<EditProcedureCallsVisitor>::visit_StructInstanceMember(x);
            if (v.proc2newproc.find(ASRUtils::symbol_get_past_external(x.m_m)) != v.proc2newproc.end()) {
                ASR::symbol_t* new_func_sym_ = x.m_m;
                if (ASR::is_a<ASR::ExternalSymbol_t>(*x.m_m)) {
                    ASR::symbol_t* new_func = v.proc2newproc[ASRUtils::symbol_get_past_external(x.m_m)].first;
                    ASR::ExternalSymbol_t* x_sym_ext = ASR::down_cast<ASR::ExternalSymbol_t>(x.m_m);
                    // Use current_scope when the ExternalSymbol's parent
                    // symtab differs (e.g. in duplicated functions where
                    // m_m was not remapped by EditProcedureVisitor).
                    SymbolTable* target_scope = x_sym_ext->m_parent_symtab;
                    if (target_scope->get_counter() != current_scope->get_counter()) {
                        target_scope = current_scope;
                    }
                    std::string new_func_sym_name = target_scope->get_unique_name(ASRUtils::symbol_name(x.m_m));
                    new_func_sym_ = ASR::down_cast<ASR::symbol_t>(
                        ASR::make_ExternalSymbol_t(v.al, x.m_m->base.loc, target_scope,
                            s2c(v.al, new_func_sym_name), new_func, x_sym_ext->m_module_name,
                            x_sym_ext->m_scope_names, x_sym_ext->n_scope_names, ASRUtils::symbol_name(new_func),
                            x_sym_ext->m_access));
                    v.proc2newproc[x.m_m] = {new_func_sym_, {}};
                    target_scope->add_symbol(new_func_sym_name, new_func_sym_);
                } else if (ASR::is_a<ASR::Variable_t>(*x.m_m)) {
                    new_func_sym_ = v.proc2newproc[x.m_m].first;
                }
                ASR::StructInstanceMember_t& sim = const_cast<ASR::StructInstanceMember_t&>(x);
                sim.m_m = new_func_sym_;
                sim.m_type = ASRUtils::symbol_type(new_func_sym_);
            }
        }

        void visit_Struct(const ASR::Struct_t &x) {
            //just to update names of changed symbols of Struct
            ASR::ASRPassBaseWalkVisitor<EditProcedureCallsVisitor>::visit_Struct(x);
            ASR::Struct_t& ss = const_cast<ASR::Struct_t&>(x);
            for (size_t i = 0; i < x.n_members; i++) {
                ASR::symbol_t* old_sym = x.m_symtab->get_symbol(x.m_members[i]);
                if (v.proc2newproc.find(old_sym) != v.proc2newproc.end()) {
                    ss.m_members[i] = ASRUtils::symbol_name(v.proc2newproc[old_sym].first);
                }
            }
        }

        void visit_Var(const ASR::Var_t &x) {
            if (v.proc2newproc.find(x.m_v) != v.proc2newproc.end()){
                ASR::symbol_t* new_sym = v.proc2newproc[x.m_v].first;
                ASR::Var_t& vv = const_cast<ASR::Var_t&>(x);
                vv.m_v = new_sym;
                return;
            }
            if (ASR::is_a<ASR::ExternalSymbol_t>(*x.m_v) &&
                v.proc2newproc.find(ASRUtils::symbol_get_past_external(x.m_v)) != v.proc2newproc.end()) {
                ASR::symbol_t* new_func_sym_ = x.m_v;
                ASR::symbol_t* new_func = v.proc2newproc[ASRUtils::symbol_get_past_external(x.m_v)].first;
                ASR::ExternalSymbol_t* x_sym_ext = ASR::down_cast<ASR::ExternalSymbol_t>(x.m_v);
                std::string new_func_sym_name = x_sym_ext->m_parent_symtab->get_unique_name(ASRUtils::symbol_name(x.m_v));
                new_func_sym_ = ASR::down_cast<ASR::symbol_t>(
                    ASR::make_ExternalSymbol_t(v.al, x.m_v->base.loc, x_sym_ext->m_parent_symtab,
                        s2c(v.al, new_func_sym_name), new_func, x_sym_ext->m_module_name,
                        x_sym_ext->m_scope_names, x_sym_ext->n_scope_names, ASRUtils::symbol_name(new_func),
                        x_sym_ext->m_access));
                v.proc2newproc[x.m_v] = {new_func_sym_, {}};
                x_sym_ext->m_parent_symtab->add_symbol(new_func_sym_name, new_func_sym_);
                ASR::Var_t& vv = const_cast<ASR::Var_t&>(x);
                vv.m_v = new_func_sym_;
            }
        }
};

/*
Since the above visitors have replaced procedure and calls to those procedures
with arrays as arguments, we don't need the original ones anymore. So we remove
them from the ASR. The reason to do this is that some backends like WASM don't
have support for accepting and returning arrays via array descriptors. Therefore,
they cannot generate code for such functions. To avoid backends like WASM from failing
we remove those functions by implementing and calling the following visitor.
*/
class RemoveArrayByDescriptorProceduresVisitor : public PassUtils::PassVisitor<RemoveArrayByDescriptorProceduresVisitor>
{
    private:

        PassArrayByDataProcedureVisitor& v;
        std::set<ASR::symbol_t*>& not_to_be_erased;
        bool skip_removal;

    public:

        RemoveArrayByDescriptorProceduresVisitor(Allocator& al_, PassArrayByDataProcedureVisitor& v_,
            std::set<ASR::symbol_t*>& not_to_be_erased_, bool skip_removal_=false):
            PassVisitor(al_, nullptr), v(v_), not_to_be_erased(not_to_be_erased_),
            skip_removal(skip_removal_) {}

        // Shouldn't be done because allocatable arrays when
        // assigned to array constants work fine in gfortran
        // and hence we will need calling the original function
        // and not the new one. WASM backend should be supporting
        // such cases for the following to be removed.
        template <typename T>
        void visit_Unit(const T& x) {
            T& xx = const_cast<T&>(x);
            current_scope = xx.m_symtab;

            std::vector<std::pair<std::string, ASR::symbol_t*>> to_be_erased;

            for( auto& item: current_scope->get_scope() ) {
                if (ASR::is_a<ASR::Function_t>(*item.second)) {
                    SymbolTable* current_scope_copy = current_scope;
                    visit_symbol(*item.second);
                    current_scope = current_scope_copy;
                }
                ASR::symbol_t* sym = item.second;
                if (ASR::is_a<ASR::ExternalSymbol_t>(*item.second)) {
                    sym = ASR::down_cast<ASR::ExternalSymbol_t>(item.second)->m_external;
                }
                if( v.proc2newproc.find(sym) != v.proc2newproc.end() ) {
                    LCOMPILERS_ASSERT(item.first == ASRUtils::symbol_name(item.second))
                    to_be_erased.push_back({item.first, sym});
                }
                if ( ASR::is_a<ASR::Module_t>(*item.second) ||
                    ASR::is_a<ASR::Program_t>(*item.second) ||
                    ASR::is_a<ASR::Function_t>(*item.second) ||
                    ASR::is_a<ASR::GpuKernelFunction_t>(*item.second) ||
                    ASR::is_a<ASR::Struct_t>(*item.second) ||
                    ASR::is_a<ASR::Block_t>(*item.second) ||
                    ASR::is_a<ASR::AssociateBlock_t>(*item.second)) {
                    SymbolTable* current_scope_copy = current_scope;
                    visit_symbol(*item.second);
                    current_scope = current_scope_copy;
                }
            }

            if (!skip_removal) {
                for (auto &item: to_be_erased) {
                    if (not_to_be_erased.find(item.second) != not_to_be_erased.end()) {
                        continue;
                    }
                    // If this function is in a submodule, check if the parent
                    // module's counterpart is protected (referenced by an SMD).
                    // The submodule provides the body for the parent module's
                    // interface function, so it must not be erased either.
                    bool protect = false;
                    ASR::asr_t* owner = current_scope->asr_owner;
                    if (ASR::is_a<ASR::symbol_t>(*owner)) {
                        ASR::symbol_t* owner_sym = ASR::down_cast<ASR::symbol_t>(owner);
                        if (ASR::is_a<ASR::Module_t>(*owner_sym)) {
                            ASR::Module_t* mod = ASR::down_cast<ASR::Module_t>(owner_sym);
                            if (mod->m_parent_module && std::strlen(mod->m_parent_module) > 0) {
                                ASR::symbol_t* parent_mod_sym =
                                    current_scope->parent->resolve_symbol(mod->m_parent_module);
                                if (parent_mod_sym && ASR::is_a<ASR::Module_t>(*parent_mod_sym)) {
                                    ASR::Module_t* parent_mod = ASR::down_cast<ASR::Module_t>(parent_mod_sym);
                                    ASR::symbol_t* parent_func =
                                        parent_mod->m_symtab->resolve_symbol(item.first);
                                    if (parent_func &&
                                            not_to_be_erased.find(parent_func) != not_to_be_erased.end()) {
                                        protect = true;
                                    }
                                    // Also check if any Struct in the parent
                                    // module has an SMD referencing this
                                    // function. When compiling a submodule,
                                    // the Struct is only reachable through
                                    // ExternalSymbols so
                                    // visit_StructMethodDeclaration may not
                                    // have been called.
                                    if (!protect && parent_func) {
                                        for (auto &sym_item : parent_mod->m_symtab->get_scope()) {
                                            if (!ASR::is_a<ASR::Struct_t>(*sym_item.second)) continue;
                                            ASR::Struct_t* st = ASR::down_cast<ASR::Struct_t>(sym_item.second);
                                            for (auto &st_item : st->m_symtab->get_scope()) {
                                                if (!ASR::is_a<ASR::StructMethodDeclaration_t>(*st_item.second)) continue;
                                                ASR::StructMethodDeclaration_t* smd =
                                                    ASR::down_cast<ASR::StructMethodDeclaration_t>(st_item.second);
                                                if (ASRUtils::symbol_get_past_external(smd->m_proc) == parent_func) {
                                                    protect = true;
                                                    break;
                                                }
                                            }
                                            if (protect) break;
                                        }
                                    }
                                }
                            }
                        }
                    }
                    if (!protect) {
                        current_scope->erase_symbol(item.first);
                    }
                }
            }
        }

        void visit_TranslationUnit(const ASR::TranslationUnit_t& x) {
            visit_Unit(x);
        }

        void visit_Program(const ASR::Program_t& x) {
            visit_Unit(x);
        }

        void visit_Function(const ASR::Function_t& x) {
            visit_Unit(x);
        }

        void visit_Module(const ASR::Module_t& x) {
            if (x.m_intrinsic) {
                return ;
            }

            visit_Unit(x);
        }

        void visit_Struct(const ASR::Struct_t& x) {
            ASR::ASRPassBaseWalkVisitor<RemoveArrayByDescriptorProceduresVisitor>::visit_Struct(x);
            visit_Unit(x);
        }

        void visit_Block(const ASR::Block_t& x) {
            visit_Unit(x);
        }

        void visit_AssociateBlock(const ASR::AssociateBlock_t& x) {
            visit_Unit(x);
        }

        void visit_GpuKernelFunction(const ASR::GpuKernelFunction_t& x) {
            visit_Unit(x);
        }

        // Note: We intentionally do NOT update m_proc to the ____N version.
        // The vtable is linkonce_odr and must reference the original
        // (descriptor-based) functions so it stays identical across all
        // compilation units. We also mark the original function as
        // not-to-be-erased so it remains available for the vtable.
        void visit_StructMethodDeclaration(const ASR::StructMethodDeclaration_t &x){
            ASR::ASRPassBaseWalkVisitor<RemoveArrayByDescriptorProceduresVisitor>::visit_StructMethodDeclaration(x);
            ASR::symbol_t* proc = ASRUtils::symbol_get_past_external(x.m_proc);
            // Always protect SMD-referenced functions. For submodule
            // procedures, proc points to the parent module's interface
            // (not in proc2newproc), but the submodule's implementation
            // must still be kept so the vtable can reference it.
            not_to_be_erased.insert(proc);
        }
};

/*
    When pass_array_by_data transforms a callback interface (e.g. `cb`) but the
    actual function passed through it (e.g. `f`) cannot be transformed (its body
    contains reshape), the procedure variable's type would be updated to the
    transformed interface while the actual function keeps its original signature.
    This causes an LLVM IR type mismatch at the call site.

    This visitor detects such mismatches after PassArrayByDataProcedureVisitor
    has populated proc2newproc, and removes the offending interface entries
    before EditProcedureVisitor updates type declarations.
 */
class CallbackMismatchCleanup : public ASR::BaseWalkVisitor<CallbackMismatchCleanup> {
public:
    PassArrayByDataProcedureVisitor& v;
    std::set<ASR::symbol_t*> to_remove;
    std::map<ASR::symbol_t*, std::set<ASR::symbol_t*>> iface_to_assigned;

    CallbackMismatchCleanup(PassArrayByDataProcedureVisitor& v_) : v(v_) {}

    void check_callback_args(ASR::symbol_t* callee_name,
                             ASR::call_arg_t* args, size_t n_args) {
        ASR::symbol_t* callee_sym = ASRUtils::symbol_get_past_external(callee_name);
        if (!ASR::is_a<ASR::Function_t>(*callee_sym)) return;
        ASR::Function_t* callee = ASR::down_cast<ASR::Function_t>(callee_sym);

        for (size_t i = 0; i < n_args && i < callee->n_args; i++) {
            if (!args[i].m_value) continue;
            if (!ASR::is_a<ASR::Var_t>(*args[i].m_value)) continue;

            ASR::symbol_t* arg_sym = ASR::down_cast<ASR::Var_t>(
                args[i].m_value)->m_v;
            ASR::symbol_t* arg_resolved = ASRUtils::symbol_get_past_external(
                arg_sym);

            // Is the argument a function being passed as a callback?
            if (!ASR::is_a<ASR::Function_t>(*arg_resolved)) continue;
            // Was this function NOT transformed?
            if (v.proc2newproc.find(arg_resolved) != v.proc2newproc.end()) continue;

            // Get the corresponding parameter's type_declaration (the interface)
            if (!ASR::is_a<ASR::Var_t>(*callee->m_args[i])) continue;
            ASR::symbol_t* param_sym = ASR::down_cast<ASR::Var_t>(
                callee->m_args[i])->m_v;
            if (!ASR::is_a<ASR::Variable_t>(*param_sym)) continue;
            ASR::Variable_t* param = ASR::down_cast<ASR::Variable_t>(param_sym);
            if (!param->m_type_declaration) continue;

            ASR::symbol_t* type_decl = ASRUtils::symbol_get_past_external(
                param->m_type_declaration);

            // If the interface WAS transformed → mismatch
            if (v.proc2newproc.find(type_decl) != v.proc2newproc.end()) {
                to_remove.insert(type_decl);
            }
        }
    }
    static ASR::symbol_t* get_slot_iface(ASR::expr_t* target) {
        ASR::symbol_t* slot_var = nullptr;
        if (ASR::is_a<ASR::StructInstanceMember_t>(*target)) {
            slot_var = ASR::down_cast<ASR::StructInstanceMember_t>(target)->m_m;
        } else if (ASR::is_a<ASR::Var_t>(*target)) {
            slot_var = ASR::down_cast<ASR::Var_t>(target)->m_v;
        } else {
            return nullptr;
        }
        ASR::symbol_t* resolved = ASRUtils::symbol_get_past_external(slot_var);
        if (!resolved || !ASR::is_a<ASR::Variable_t>(*resolved)) return nullptr;
        ASR::Variable_t* var = ASR::down_cast<ASR::Variable_t>(resolved);
        if (!var->m_type_declaration) return nullptr;
        ASR::symbol_t* iface = ASRUtils::symbol_get_past_external(
            var->m_type_declaration);
        if (!iface || !ASR::is_a<ASR::Function_t>(*iface)) return nullptr;
        return iface;
    }

    static ASR::symbol_t* get_rhs_function(ASR::expr_t* value) {
        if (!value || !ASR::is_a<ASR::Var_t>(*value)) return nullptr;
        ASR::symbol_t* sym = ASR::down_cast<ASR::Var_t>(value)->m_v;
        ASR::symbol_t* resolved = ASRUtils::symbol_get_past_external(sym);
        if (!resolved || !ASR::is_a<ASR::Function_t>(*resolved)) return nullptr;
        return resolved;
    }

    void record_assignment(ASR::expr_t* target, ASR::expr_t* value) {
        ASR::symbol_t* iface = get_slot_iface(target);
        ASR::symbol_t* fn = get_rhs_function(value);
        if (iface && fn) {
            iface_to_assigned[iface].insert(fn);
        }
    }

    void visit_Associate(const ASR::Associate_t& x) {
        record_assignment(x.m_target, x.m_value);
        BaseWalkVisitor::visit_Associate(x);
    }

    void visit_Variable(const ASR::Variable_t& x) {
        // Capture default initialisation `procedure(iface), pointer :: p => f`.
        if (x.m_type_declaration && x.m_symbolic_value) {
            ASR::symbol_t* iface = ASRUtils::symbol_get_past_external(
                x.m_type_declaration);
            if (iface && ASR::is_a<ASR::Function_t>(*iface)) {
                ASR::symbol_t* fn = get_rhs_function(x.m_symbolic_value);
                if (fn) {
                    iface_to_assigned[iface].insert(fn);
                }
            }
        }
        BaseWalkVisitor::visit_Variable(x);
    }

    void visit_SubroutineCall(const ASR::SubroutineCall_t& x) {
        check_callback_args(x.m_name, x.m_args, x.n_args);
        BaseWalkVisitor::visit_SubroutineCall(x);
    }

    void visit_FunctionCall(const ASR::FunctionCall_t& x) {
        check_callback_args(x.m_name, x.m_args, x.n_args);
        BaseWalkVisitor::visit_FunctionCall(x);
    }

    void resolve_pointer_assignment_groups() {
        for (auto& kv : iface_to_assigned) {
            ASR::symbol_t* iface = kv.first;
            bool any_untransformable = false;
            for (ASR::symbol_t* fn : kv.second) {
                if (v.proc2newproc.find(fn) == v.proc2newproc.end()) {
                    any_untransformable = true;
                    break;
                }
            }
            if (!any_untransformable) continue;
            if (v.proc2newproc.find(iface) != v.proc2newproc.end()) {
                to_remove.insert(iface);
            }
            for (ASR::symbol_t* fn : kv.second) {
                if (v.proc2newproc.find(fn) != v.proc2newproc.end()) {
                    to_remove.insert(fn);
                }
            }
        }
    }

    void apply() {
        resolve_pointer_assignment_groups();
        for (ASR::symbol_t* sym : to_remove) {
            ASR::Function_t* new_func = ASR::down_cast<ASR::Function_t>(
                v.proc2newproc[sym].first);
            SymbolTable* scope = new_func->m_symtab->parent;
            scope->erase_symbol(std::string(new_func->m_name));
            v.newprocs.erase(v.proc2newproc[sym].first);
            v.proc2newproc.erase(sym);
        }
    }
};

void pass_array_by_data(Allocator &al, ASR::TranslationUnit_t &unit,
                        const LCompilers::PassOptions& pass_options) {
    PassArrayByDataProcedureVisitor v(al, pass_options);
    v.visit_TranslationUnit(unit);
    CallbackMismatchCleanup cleanup(v);
    cleanup.visit_TranslationUnit(unit);
    cleanup.apply();
    EditProcedureVisitor e(v);
    e.visit_TranslationUnit(unit);
    std::set<ASR::symbol_t*> not_to_be_erased;
    EditProcedureCallsVisitor u(al, v, not_to_be_erased, pass_options);
    u.visit_TranslationUnit(unit);
    /*
        RemoveArrayByDescriptorProceduresVisitor removes original (descriptor-
        based) procedures that have been replaced by ____N versions, unless
        skip_removal is set (separate-compilation mode, where other compilation
        units may still reference the originals).

        Note: StructMethodDeclaration.m_proc is intentionally NOT updated to
        point to the ____N version.  The vtable uses linkonce_odr linkage and
        must be identical across all compilation units.  Since ____N versions
        are only created when function bodies are available, updating the SMD
        would make the vtable inconsistent between submodules (which have the
        bodies) and other units that merely `use` the module.

        If separate compilation is enabled using `--separate-compilation`, then we don't
        drop the original ( unused ) procedures. This is for the module procedures where when
        loaded from other file transformation may or maynot take place and then while linking
        it shows missing symbol. There can be multiple reasons:

        1. Module procedure is transformed in current file but not in the other file. -- this approach fixes it.
            a. Function `get_midpoints(A, B)` where A(:) and B(:) are arrays, get transformed in current file, but
               in other file, it got called as `print *, get_midpoints(A(1:3), b(1:3))`, LFortran treats these as
               pointers and hence doesn't transform it.
        2. Module procedure is not transformed in current file but is done in other file -- very less prone to happen.
            a. For the functions where reshape is used over Function arguments, it is not transformed in current file but
               in other file it is transformed as these routines are marked as external ( meaning n_body = 0 ).
    */
    RemoveArrayByDescriptorProceduresVisitor x(al, v, not_to_be_erased,
        pass_options.skip_removal_of_unused_procedures_in_pass_array_by_data);
    x.visit_TranslationUnit(unit);
    PassUtils::UpdateDependenciesVisitor y(al);
    y.visit_TranslationUnit(unit);
}

} // namespace LCompilers
