Julia's runtime provides a lot of functionality used by base Julia code. A subset of this is needed to support basic data structures like arrays, dicts, and strings. Here is a list of the ccall's used by base Julia code. The most important ones for basic wasm support are:
# most important
abstractdict.jl
:jl_eqtable_get
:jl_eqtable_nextind
:jl_eqtable_pop
:jl_eqtable_put
:jl_idtable_rehash
:memset
array.jl
:jl_array_copy
:jl_array_del_at
:jl_array_del_beg
:jl_array_del_end
:jl_array_grow_at
:jl_array_grow_beg
:jl_array_grow_end
:jl_array_isassigned
:jl_array_ptr_copy
:jl_array_sizehint
:jl_array_store_unboxed
:jl_islayout_inline
:jl_reshape_array
:memcmp
:memcpy
:memmove
:memset
boot.jl
:jl_alloc_array_1d
:jl_alloc_array_2d
:jl_alloc_array_3d
:jl_array_ptr
:jl_f_new_module
:jl_gc_new_weakref_th
:jl_get_keyword_sorter
:jl_get_kwsorter
:jl_get_ptls_states
:jl_load_
:jl_new_array
:jl_new_structv
:jl_new_task
:jl_new_typevar
:jl_set_istopmod
:jl_static_show
:jl_string_ptr
:jl_symbol_n
:jl_toplevel_eval_in
:jl_type_unionall
:jl_typemax_uint
:jl_uv_putb
:jl_uv_putc
:jl_uv_puts
dict.jl
:jl_arrayunset
error.jl
:jl_get_backtrace
:jl_throw
:jl_rethrow
:jl_rethrow_other
pointer.jl
:jl_array_ptr
:jl_ptr_to_array
:jl_ptr_to_array_1d
:jl_symbol_name
:jl_value_ptr
strings/basic.jl
:strcmp
strings/search.jl
:memchr
:memrchr
strings/string.jl
:jl_alloc_string
:jl_array_to_string
:jl_cstr_to_string
:jl_pchar_to_string
:jl_string_to_array
:memcmp
:memset
:u8_isvalid
strings/substring.jl
:memcmp
strings/unicode.jl
:utf8proc_category
:utf8proc_category_string
:utf8proc_charwidth
:utf8proc_decompose
:utf8proc_errmsg
:utf8proc_grapheme_break
:utf8proc_grapheme_break_stateful
:utf8proc_reencode
:utf8proc_tolower
:utf8proc_totitle
:utf8proc_toupper
strings/util.jl
:memcmp
There are lots more, though:
atomics.jl
:jl_alignment
:jl_gc_safepoint
bitarray.jl
:jl_array_sizehint
c.jl
:jl_extern_c
:jl_get_UNAME
:jl_is_char_signed
:jl_sigatomic_begin
:jl_sigatomic_end
:jl_sizeof_mode_t
:memchr
checked.jl
:jl_get_LLVM_VERSION
client.jl
:jl_exit_on_sigint
:jl_parse_input_line
clipboard.jl
:CloseClipboard
:EmptyClipboard
:GetClipboardData
:GlobalAlloc
:GlobalLock
:GlobalUnlock
:OpenClipboard
:SetClipboardData
:memcpy
compiler/abstractinterpretation.jl
:jl_ast_flag_inferred
:jl_ast_flag_inlineable
:jl_instantiate_type_in_env
:jl_type_intersection_with_env
compiler/bootstrap.jl
:jl_get_world_counter
compiler/compiler.jl
:jl_set_istopmod
:jl_set_typeinf_func
compiler/optimize.jl
:abort
:jl_arrayunset
:jl_ast_flag_inferred
:jl_ast_flag_inlineable
:jl_compress_ast
:jl_get_invoke_lambda
:jl_get_spec_lambda
:jl_get_tls_world_age
:jl_gf_invoke_lookup
:jl_instantiate_type_in_env
:jl_is_cacheable_sig
:jl_set_method_inferred
:jl_type_error_new_expr
:jl_type_intersection_with_env
:jl_uncompress_ast
compiler/tfuncs.jl
:jl_argument_datatype
:jl_gf_invoke_lookup
:jl_type_intersection_with_env
compiler/typeinfer.jl
:jl_method_instance_add_backedge
:jl_method_table_add_backedge
:jl_new_code_info_uninit
:jl_typeinf_begin
:jl_typeinf_end
compiler/typeutils.jl
:jl_has_free_typevars
compiler/utilities.jl
:jl_base_relative_to
:jl_code_for_staged
:jl_copy_code_info
:jl_invoke_api
:jl_specializations_get_linfo
:jl_specializations_lookup
:jl_uncompress_ast
:strcmp
deepcopy.jl
:jl_array_isassigned
:jl_arrayref
:jl_arrayset
:jl_new_struct_uninit
:jl_set_nth_field
deprecated.jl
:jl_deprecate_binding
:jl_first_argument_datatype
:jl_function_ptr
:jl_get_current_module
:memchr
dict.jl
:jl_arrayunset
docs/basedocs.jl
function_name
function_pointer
env.jl
:FreeEnvironmentStringsW
:GetEnvironmentStringsW
:GetEnvironmentVariableW
:SetEnvironmentVariableW
:getenv
:jl_environ
:setenv
:unsetenv
:wcslen
error.jl
:jl_get_backtrace
:jl_rethrow
:jl_rethrow_other
errorshow.jl
:jl_get_world_counter
:jl_printf
:jl_static_show
:jl_stderr_stream
essentials.jl
:jl_compile_hint
event.jl
:Sleep
:jl_close_uv
:jl_safe_printf
:jl_switchto
:pause
:uv_async_init
:uv_stop
:uv_timer_get_repeat
:uv_timer_init
:uv_timer_start
:uv_timer_stop
:uv_update_time
expr.jl
:jl_gensym
:jl_macroexpand
:jl_macroexpand1
:jl_tagged_gensym
:strlen
fastmath.jl
"atan2"
"atan2f"
"llvm.powi.f32"
"llvm.powi.f64"
"pow"
"powf"
$(string(f
:sincos
:sincosf
file.jl
:GetTempFileNameW
:GetTempPathW
:_wmkdir
:_wrmdir
:close
:fchdir
:jl_fs_chmod
:jl_fs_chown
:jl_fs_rename
:jl_fs_symlink
:jl_fs_unlink
:jl_sizeof_uv_fs_t
:jl_uv_fs_req_cleanup
:jl_uv_fs_t_ptr
:mkdir
:mkdtemp
:mkstemp
:open
:rmdir
:tempnam
:uv_chdir
:uv_cwd
:uv_fs_readlink
:uv_fs_req_cleanup
:uv_fs_scandir
:uv_fs_scandir_next
filesystem.jl
:jl_fs_close
:jl_fs_read
:jl_fs_read_byte
:jl_fs_sendfile
:jl_fs_write
:jl_lseek
:jl_uv_fs_result
:uv_fs_ftruncate
:uv_fs_futime
:uv_fs_open
:uv_fs_req_cleanup
floatfuncs.jl
"fma"
"fmaf"
gcutils.jl
:jl_finalize_th
:jl_gc_add_finalizer_th
:jl_gc_add_ptr_finalizer
:jl_gc_collect
:jl_gc_enable
gmp.jl
$(gmpz(op
:__gmp_set_memory_functions
:__gmpn_cmp
:__gmpn_popcount
:__gmpz_cmp
:__gmpz_cmp_d
:__gmpz_cmp_si
:__gmpz_cmp_ui
:__gmpz_gcdext
:__gmpz_get_d
:__gmpz_get_str
:__gmpz_import
:__gmpz_init
:__gmpz_init2
:__gmpz_invert
:__gmpz_limbs_finish
:__gmpz_limbs_write
:__gmpz_mul_si
:__gmpz_popcount
:__gmpz_powm
:__gmpz_realloc2
:__gmpz_set_str
:__gmpz_setbit
:__gmpz_sizeinbase
:__gmpz_tdiv_qr
:__gmpz_tstbit
:__gmpz_ui_sub
hashing2.jl
:__gmpz_realloc2
:memcpy
memhash
initdefs.jl
:jl_exit
io.jl
:strlen
iobuffer.jl
:memchr
iostream.jl
:ios_close
:ios_eof_blocking
:ios_fd
:ios_file
:ios_flush
:ios_get_readable
:ios_get_writable
:ios_getc
:ios_isopen
:ios_peekc
:ios_peekutf8
:ios_pos
:ios_putc
:ios_read
:ios_readall
:ios_seek
:ios_seek_end
:ios_skip
:ios_trunc
:ios_write
:jl_ios_fd
:jl_ios_get_nbyte_int
:jl_nb_available
:jl_readuntil
:jl_sizeof_ios_t
:jl_take_buffer
irrationals.jl
$(string("mpfr_const_"
libc.jl
:DuplicateHandle
:FormatMessageW
:GetCurrentProcess
:GetLastError
:LocalFree
:Sleep
:_close
:_get_osfhandle
:_open_osfhandle
:calloc
:fclose
:free
:fseek
:ftell
:gethostname
:jl_clock_now
:jl_errno
:jl_flush_cstdio
:jl_getpid
:jl_gettimeofday
:jl_set_errno
:localtime_r
:malloc
:mktime
:rand
:realloc
:srand
:strerror
:strftime
:strptime
:usleep
@static
libuv.jl
:jl_global_event_loop
:jl_new_event_loop
:jl_process_events
:jl_run_event_loop
:jl_run_once
:jl_stderr_stream
:jl_stdin_stream
:jl_stdout_stream
:jl_uv_associate_julia_struct
:jl_uv_disassociate_julia_struct
:jl_uv_handle_data
:jl_uv_req_data
:jl_uv_req_set_data
:uv_err_name
:uv_handle_size
:uv_req_size
:uv_strerror
loading.jl
:getattrlist
:jl_generating_output
:jl_load_file_string
:jl_module_build_id
:jl_module_uuid
:jl_read_verify_header
:jl_restore_incremental
:jl_set_module_uuid
locks.jl
:jl_cpu_pause
:jl_cpu_wake
:jl_gc_safe_enter
:jl_gc_safe_leave
:jl_gc_safepoint
:jl_sizeof_uv_mutex
:uv_mutex_destroy
:uv_mutex_init
:uv_mutex_lock
:uv_mutex_trylock
:uv_mutex_unlock
math.jl
"llvm.pow.f32"
"llvm.pow.f64"
$(string(f
:modf
:modff
:remainder
:remainderf
meta.jl
:jl_expand
:jl_parse_string
methodshow.jl
:jl_fill_argnames
:jl_methtable_lookup
mpfr.jl
"mpfr_fma"
$(string(:mpfr_
$(string(:mpfr_set_
:__gmpfr_mpfr_get_sj
:__gmpfr_mpfr_get_uj
:mpfr_add
:mpfr_atan2
:mpfr_beta
:mpfr_cmp_d
:mpfr_cmp_si
:mpfr_cmp_ui
:mpfr_cmp_z
:mpfr_const_log2
:mpfr_copysign
:mpfr_d_div
:mpfr_div
:mpfr_div_d
:mpfr_div_si
:mpfr_div_ui
:mpfr_div_z
:mpfr_equal_p
:mpfr_fac_ui
:mpfr_fmod
:mpfr_frexp
:mpfr_get_d
:mpfr_get_emax
:mpfr_get_emax_max
:mpfr_get_emax_min
:mpfr_get_emin
:mpfr_get_emin_max
:mpfr_get_emin_min
:mpfr_get_exp
:mpfr_get_flt
:mpfr_get_patches
:mpfr_get_prec
:mpfr_get_version
:mpfr_get_z
:mpfr_greater_p
:mpfr_greaterequal_p
:mpfr_hypot
:mpfr_inf_p
:mpfr_init2
:mpfr_integer_p
:mpfr_less_p
:mpfr_lessequal_p
:mpfr_lgamma
:mpfr_log1p
:mpfr_max
:mpfr_min
:mpfr_modf
:mpfr_mul_2si
:mpfr_mul_2ui
:mpfr_mul_si
:mpfr_nan_p
:mpfr_neg
:mpfr_nextabove
:mpfr_nextbelow
:mpfr_pow
:mpfr_pow_si
:mpfr_pow_ui
:mpfr_pow_z
:mpfr_remainder
:mpfr_set
:mpfr_set_d
:mpfr_set_emax
:mpfr_set_emin
:mpfr_set_str
:mpfr_set_z
:mpfr_si_div
:mpfr_signbit
:mpfr_sin_cos
:mpfr_snprintf
:mpfr_sprintf
:mpfr_sqrt
:mpfr_trunc
:mpfr_ui_div
:mpfr_z_sub
namedtuple.jl
:jl_new_structv
options.jl
:jl_sizeof_jl_options
:jl_throw
parse.jl
:jl_try_substrtod
:jl_try_substrtof
:memcmp
path.jl
:GetFullPathNameW
:GetLongPathNameW
:realpath
:uv_os_homedir
pcre.jl
:pcre2_code_free_8
:pcre2_compile_8
:pcre2_get_error_message_8
:pcre2_get_ovector_count_8
:pcre2_get_ovector_pointer_8
:pcre2_jit_compile_8
:pcre2_jit_stack_assign_8
:pcre2_jit_stack_create_8
:pcre2_jit_stack_free_8
:pcre2_match_8
:pcre2_match_context_create_8
:pcre2_match_context_free_8
:pcre2_match_data_create_from_pattern_8
:pcre2_match_data_free_8
:pcre2_pattern_info_8
:pcre2_substring_copy_bynumber_8
:pcre2_substring_length_bynumber_8
:pcre2_substring_number_from_name_8
printf.jl
:memset
:mpfr_snprintf
process.jl
:jl_close_uv
:jl_forceclose_uv
:jl_spawn
:jl_uv_process_data
:memchr
:uv_process_kill
reflection.jl
:jl_argument_datatype
:jl_binding_resolved_p
:jl_field_index
:jl_first_argument_datatype
:jl_get_field_offset
:jl_get_module_of_binding
:jl_get_world_counter
:jl_gf_invoke_lookup
:jl_is_binding_deprecated
:jl_is_const
:jl_is_in_pure_context
:jl_matching_methods
:jl_method_exists
:jl_method_table_disable
:jl_module_exports_p
:jl_module_name
:jl_module_names
:jl_module_parent
:jl_object_id
:jl_type_intersection
:jl_uncompress_ast
rounding.jl
:fegetround
:fesetround
:jl_get_fenv_consts
:jl_get_zero_subnormals
:jl_set_zero_subnormals
show.jl
:jl_binding_owner
:jl_has_typevar
:jl_id_char
:jl_id_start_char
:jl_intrinsic_name
:jl_is_operator
:jl_is_unary_and_binary_operator
:jl_is_unary_operator
:jl_operator_precedence
special/gamma.jl
:lgamma_r
:lgammaf_r
:tgamma
:tgammaf
special/hyperbolic.jl
"__ldexp_exp"
"__ldexp_expf"
stacktraces.jl
:jl_backtrace_from_here
:jl_lookup_code_address
stat.jl
$(Expr(:quote
:jl_sizeof_stat
:jl_stat_blksize
:jl_stat_blocks
:jl_stat_ctime
:jl_stat_dev
:jl_stat_gid
:jl_stat_ino
:jl_stat_mode
:jl_stat_mtime
:jl_stat_nlink
:jl_stat_rdev
:jl_stat_size
:jl_stat_uid
stream.jl
:CloseHandle
:SetStdHandle
:_open_osfhandle
:close
:jl_close_uv
:jl_forceclose_uv
:jl_ispty
:jl_pipe_open
:jl_uv_buf_len
:jl_uv_buf_set_base
:jl_uv_buf_set_len
:jl_uv_file_handle
:jl_uv_handle_type
:jl_uv_write
:uv_fileno
:uv_is_readable
:uv_is_writable
:uv_pipe
:uv_pipe_init
:uv_read_start
:uv_read_stop
:uv_tty_get_winsize
:uv_tty_init
summarysize.jl
:jl_array_isassigned
:jl_value_ptr
sysimg.jl
:jl_hrtime
:jl_module_parent
:jl_prepend_cwd
:jl_set_istopmod
sysinfo.jl
:GetVersion
:jl_SC_CLK_TCK
:jl_cpu_cores
:jl_get_ARCH
:jl_get_JIT
:jl_get_UNAME
:jl_get_cpu_name
:jl_get_julia_bindir
:jl_maxrss
:uv_cpu_info
:uv_free_cpu_info
:uv_get_free_memory
:uv_get_process_title
:uv_get_total_memory
:uv_loadavg
:uv_set_process_title
:uv_uptime
task.jl
:jl_get_current_task
:jl_is_task_started
threadcall.jl
$f
:jl_queue_work
threadingconstructs.jl
:jl_threadid
:jl_threading_run
util.jl
:CoTaskMemFree
:CredPackAuthenticationBufferW
:CredUIPromptForWindowsCredentialsW
:CredUnPackAuthenticationBufferW
:SecureZeroMemory
:_getch
:getpass
:jl_crc32c
:jl_gc_num
:jl_gc_total_bytes
:jl_gc_total_hrtime
:jl_is_debugbuild
:memset
version.jl
:jl_clock_now