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std: even more efficient inline assembly

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This commit is contained in:
Andrew Kelley 2015-12-15 02:47:39 -07:00
parent 673d638070
commit 1f48b626a1
4 changed files with 8 additions and 15 deletions
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2
example/hello_world/hello.zig
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@ -2,7 +2,7 @@ export executable "hello";
use "std.zig";
export fn main(argc: isize, argv: &&u8, env: &&u8) -> i32 {
pub fn main(argc: isize, argv: &&u8, env: &&u8) -> i32 {
// TODO implicit coercion from array to string
print_str("Hello, world!\n" as string);
return 0;

2
src/analyze.cpp
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@ -315,7 +315,7 @@ static void preview_function_declarations(CodeGen *g, ImportTableEntry *import,
auto entry = import->fn_table.maybe_get(proto_name);
bool skip = false;
bool is_internal = (proto_node->data.fn_proto.visib_mod != FnProtoVisibModExport);
bool is_pub = (proto_node->data.fn_proto.visib_mod == FnProtoVisibModPub);
bool is_pub = (proto_node->data.fn_proto.visib_mod != FnProtoVisibModPrivate);
if (entry) {
add_node_error(g, node,
buf_sprintf("redefinition of '%s'", buf_ptr(proto_name)));

2
src/codegen.cpp
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@ -1611,7 +1611,7 @@ static ImportTableEntry *codegen_add_code(CodeGen *g, Buf *src_dirname, Buf *src
assert(proto_node->type == NodeTypeFnProto);
Buf *proto_name = &proto_node->data.fn_proto.name;
bool is_exported = (proto_node->data.fn_proto.visib_mod == FnProtoVisibModExport);
bool is_exported = (proto_node->data.fn_proto.visib_mod != FnProtoVisibModPrivate);
if (buf_eql_str(proto_name, "main") && is_exported) {
g->insert_bootstrap_code = true;

17
std/bootstrap.zig
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@ -1,16 +1,9 @@
use "std.zig";
// TODO conditionally compile this differently for non-ELF
#attribute("naked")
export fn _start() -> unreachable {
// TODO conditionally compile this differently for other architectures and other OSes
asm volatile ("
mov (%%rsp), %%rdi // first parameter is argc
lea 0x8(%%rsp), %%rsi // second parameter is argv
lea 0x10(%%rsp,%%rdi,8), %%rdx // third paremeter is env
callq main
mov %%rax, %%rdi // return value is the parameter to exit syscall
mov $60, %%rax // 60 is exit syscall number
syscall
");
unreachable
const argc = asm("mov (%%rsp), %[argc]" : [argc] "=r" (return isize));
const argv = asm("lea 0x8(%%rsp), %[argv]" : [argv] "=r" (return &&u8));
const env = asm("lea 0x10(%%rsp,%%rdi,8), %[env]" : [env] "=r" (return &&u8));
exit(main(argc, argv, env))
}