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rustc: Fix main() entry point signature on 64bit

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To match the C signature, main() should be generated with C int type
for the argc parameter and result, i.e. i32 instead of i64 on 64bit.

That way it no longer relies on the upper 32 bits being zero, which I'm
not sure is guaranteed by ABIs or startup code.
This commit is contained in:
Daniel Klauer 2017-09-22 00:36:10 +02:00
parent 6c9a4ba8eb
commit c2fe69b9bd
1 changed files with 14 additions and 6 deletions
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20
src/librustc_trans/base.rs
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@ -77,7 +77,6 @@ use value::Value;
use rustc::util::nodemap::{NodeSet, FxHashMap, FxHashSet, DefIdSet}; use rustc::util::nodemap::{NodeSet, FxHashMap, FxHashSet, DefIdSet};
use CrateInfo; use CrateInfo;
use libc::c_uint;
use std::any::Any; use std::any::Any;
use std::cell::RefCell; use std::cell::RefCell;
use std::ffi::{CStr, CString}; use std::ffi::{CStr, CString};
@ -692,7 +691,8 @@ fn maybe_create_entry_wrapper(ccx: &CrateContext) {
sp: Span, sp: Span,
rust_main: ValueRef, rust_main: ValueRef,
use_start_lang_item: bool) { use_start_lang_item: bool) {
let llfty = Type::func(&[ccx.isize_ty(), Type::i8p(ccx).ptr_to()], &ccx.isize_ty()); // Signature of native main(), corresponding to C's `int main(int, char **)`
let llfty = Type::func(&[Type::c_int(ccx), Type::i8p(ccx).ptr_to()], &Type::c_int(ccx));
if declare::get_defined_value(ccx, "main").is_some() { if declare::get_defined_value(ccx, "main").is_some() {
// FIXME: We should be smart and show a better diagnostic here. // FIXME: We should be smart and show a better diagnostic here.
@ -711,19 +711,27 @@ fn maybe_create_entry_wrapper(ccx: &CrateContext) {
debuginfo::gdb::insert_reference_to_gdb_debug_scripts_section_global(ccx, &bld); debuginfo::gdb::insert_reference_to_gdb_debug_scripts_section_global(ccx, &bld);
// Params from native main() used as args for rust start function
let param_argc = get_param(llfn, 0);
let param_argv = get_param(llfn, 1);
let arg_argc = bld.intcast(param_argc, ccx.isize_ty(), true);
let arg_argv = param_argv;
let (start_fn, args) = if use_start_lang_item { let (start_fn, args) = if use_start_lang_item {
let start_def_id = ccx.tcx().require_lang_item(StartFnLangItem); let start_def_id = ccx.tcx().require_lang_item(StartFnLangItem);
let start_instance = Instance::mono(ccx.tcx(), start_def_id); let start_instance = Instance::mono(ccx.tcx(), start_def_id);
let start_fn = callee::get_fn(ccx, start_instance); let start_fn = callee::get_fn(ccx, start_instance);
(start_fn, vec![bld.pointercast(rust_main, Type::i8p(ccx).ptr_to()), get_param(llfn, 0), (start_fn, vec![bld.pointercast(rust_main, Type::i8p(ccx).ptr_to()),
get_param(llfn, 1)]) arg_argc, arg_argv])
} else { } else {
debug!("using user-defined start fn"); debug!("using user-defined start fn");
(rust_main, vec![get_param(llfn, 0 as c_uint), get_param(llfn, 1 as c_uint)]) (rust_main, vec![arg_argc, arg_argv])
}; };
let result = bld.call(start_fn, &args, None); let result = bld.call(start_fn, &args, None);
bld.ret(result);
// Return rust start function's result from native main()
bld.ret(bld.intcast(result, Type::c_int(ccx), true));
} }
} }