rust/crates/hir_expand/src/builtin_macro.rs
2021-01-25 13:31:03 +02:00

751 lines
22 KiB
Rust

//! Builtin macro
use crate::{
db::AstDatabase, name, quote, AstId, CrateId, EagerMacroId, LazyMacroId, MacroCallId,
MacroDefId, MacroDefKind, TextSize,
};
use base_db::{AnchoredPath, FileId};
use either::Either;
use mbe::{parse_to_token_tree, ExpandResult};
use parser::FragmentKind;
use syntax::ast::{self, AstToken};
macro_rules! register_builtin {
( LAZY: $(($name:ident, $kind: ident) => $expand:ident),* , EAGER: $(($e_name:ident, $e_kind: ident) => $e_expand:ident),* ) => {
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum BuiltinFnLikeExpander {
$($kind),*
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum EagerExpander {
$($e_kind),*
}
impl BuiltinFnLikeExpander {
pub fn expand(
&self,
db: &dyn AstDatabase,
id: LazyMacroId,
tt: &tt::Subtree,
) -> ExpandResult<tt::Subtree> {
let expander = match *self {
$( BuiltinFnLikeExpander::$kind => $expand, )*
};
expander(db, id, tt)
}
}
impl EagerExpander {
pub fn expand(
&self,
db: &dyn AstDatabase,
arg_id: EagerMacroId,
tt: &tt::Subtree,
) -> ExpandResult<Option<(tt::Subtree, FragmentKind)>> {
let expander = match *self {
$( EagerExpander::$e_kind => $e_expand, )*
};
expander(db,arg_id,tt)
}
}
fn find_by_name(ident: &name::Name) -> Option<Either<BuiltinFnLikeExpander, EagerExpander>> {
match ident {
$( id if id == &name::name![$name] => Some(Either::Left(BuiltinFnLikeExpander::$kind)), )*
$( id if id == &name::name![$e_name] => Some(Either::Right(EagerExpander::$e_kind)), )*
_ => return None,
}
}
};
}
pub fn find_builtin_macro(
ident: &name::Name,
krate: CrateId,
ast_id: AstId<ast::Macro>,
) -> Option<MacroDefId> {
let kind = find_by_name(ident)?;
match kind {
Either::Left(kind) => Some(MacroDefId {
krate,
ast_id: Some(ast_id),
kind: MacroDefKind::BuiltIn(kind),
local_inner: false,
}),
Either::Right(kind) => Some(MacroDefId {
krate,
ast_id: Some(ast_id),
kind: MacroDefKind::BuiltInEager(kind),
local_inner: false,
}),
}
}
register_builtin! {
LAZY:
(column, Column) => column_expand,
(file, File) => file_expand,
(line, Line) => line_expand,
(module_path, ModulePath) => module_path_expand,
(assert, Assert) => assert_expand,
(stringify, Stringify) => stringify_expand,
(format_args, FormatArgs) => format_args_expand,
// format_args_nl only differs in that it adds a newline in the end,
// so we use the same stub expansion for now
(format_args_nl, FormatArgsNl) => format_args_expand,
(llvm_asm, LlvmAsm) => asm_expand,
(asm, Asm) => asm_expand,
EAGER:
(compile_error, CompileError) => compile_error_expand,
(concat, Concat) => concat_expand,
(include, Include) => include_expand,
(include_bytes, IncludeBytes) => include_bytes_expand,
(include_str, IncludeStr) => include_str_expand,
(env, Env) => env_expand,
(option_env, OptionEnv) => option_env_expand
}
fn module_path_expand(
_db: &dyn AstDatabase,
_id: LazyMacroId,
_tt: &tt::Subtree,
) -> ExpandResult<tt::Subtree> {
// Just return a dummy result.
ExpandResult::ok(quote! { "module::path" })
}
fn line_expand(
_db: &dyn AstDatabase,
_id: LazyMacroId,
_tt: &tt::Subtree,
) -> ExpandResult<tt::Subtree> {
// dummy implementation for type-checking purposes
let line_num = 0;
let expanded = quote! {
#line_num
};
ExpandResult::ok(expanded)
}
fn stringify_expand(
db: &dyn AstDatabase,
id: LazyMacroId,
_tt: &tt::Subtree,
) -> ExpandResult<tt::Subtree> {
let loc = db.lookup_intern_macro(id);
let macro_content = {
let arg = match loc.kind.arg(db) {
Some(arg) => arg,
None => return ExpandResult::only_err(mbe::ExpandError::UnexpectedToken),
};
let macro_args = arg;
let text = macro_args.text();
let without_parens = TextSize::of('(')..text.len() - TextSize::of(')');
text.slice(without_parens).to_string()
};
let expanded = quote! {
#macro_content
};
ExpandResult::ok(expanded)
}
fn column_expand(
_db: &dyn AstDatabase,
_id: LazyMacroId,
_tt: &tt::Subtree,
) -> ExpandResult<tt::Subtree> {
// dummy implementation for type-checking purposes
let col_num = 0;
let expanded = quote! {
#col_num
};
ExpandResult::ok(expanded)
}
fn assert_expand(
_db: &dyn AstDatabase,
_id: LazyMacroId,
tt: &tt::Subtree,
) -> ExpandResult<tt::Subtree> {
// A hacky implementation for goto def and hover
// We expand `assert!(cond, arg1, arg2)` to
// ```
// {(cond, &(arg1), &(arg2));}
// ```,
// which is wrong but useful.
let mut args = Vec::new();
let mut current = Vec::new();
for tt in tt.token_trees.iter().cloned() {
match tt {
tt::TokenTree::Leaf(tt::Leaf::Punct(p)) if p.char == ',' => {
args.push(current);
current = Vec::new();
}
_ => {
current.push(tt);
}
}
}
if !current.is_empty() {
args.push(current);
}
let arg_tts = args.into_iter().flat_map(|arg| {
quote! { &(##arg), }
}.token_trees).collect::<Vec<_>>();
let expanded = quote! {
{ { (##arg_tts); } }
};
ExpandResult::ok(expanded)
}
fn file_expand(
_db: &dyn AstDatabase,
_id: LazyMacroId,
_tt: &tt::Subtree,
) -> ExpandResult<tt::Subtree> {
// FIXME: RA purposefully lacks knowledge of absolute file names
// so just return "".
let file_name = "";
let expanded = quote! {
#file_name
};
ExpandResult::ok(expanded)
}
fn format_args_expand(
_db: &dyn AstDatabase,
_id: LazyMacroId,
tt: &tt::Subtree,
) -> ExpandResult<tt::Subtree> {
// We expand `format_args!("", a1, a2)` to
// ```
// std::fmt::Arguments::new_v1(&[], &[
// std::fmt::ArgumentV1::new(&arg1,std::fmt::Display::fmt),
// std::fmt::ArgumentV1::new(&arg2,std::fmt::Display::fmt),
// ])
// ```,
// which is still not really correct, but close enough for now
let mut args = Vec::new();
let mut current = Vec::new();
for tt in tt.token_trees.iter().cloned() {
match tt {
tt::TokenTree::Leaf(tt::Leaf::Punct(p)) if p.char == ',' => {
args.push(current);
current = Vec::new();
}
_ => {
current.push(tt);
}
}
}
if !current.is_empty() {
args.push(current);
}
if args.is_empty() {
return ExpandResult::only_err(mbe::ExpandError::NoMatchingRule);
}
for arg in &mut args {
// Remove `key =`.
if matches!(arg.get(1), Some(tt::TokenTree::Leaf(tt::Leaf::Punct(p))) if p.char == '=' && p.spacing != tt::Spacing::Joint)
{
arg.drain(..2);
}
}
let _format_string = args.remove(0);
let arg_tts = args.into_iter().flat_map(|arg| {
quote! { std::fmt::ArgumentV1::new(&(##arg), std::fmt::Display::fmt), }
}.token_trees).collect::<Vec<_>>();
let expanded = quote! {
std::fmt::Arguments::new_v1(&[], &[##arg_tts])
};
ExpandResult::ok(expanded)
}
fn asm_expand(
_db: &dyn AstDatabase,
_id: LazyMacroId,
_tt: &tt::Subtree,
) -> ExpandResult<tt::Subtree> {
// both asm and llvm_asm don't return anything, so we can expand them to nothing,
// for now
let expanded = quote! {
()
};
ExpandResult::ok(expanded)
}
fn unquote_str(lit: &tt::Literal) -> Option<String> {
let lit = ast::make::tokens::literal(&lit.to_string());
let token = ast::String::cast(lit)?;
token.value().map(|it| it.into_owned())
}
fn compile_error_expand(
_db: &dyn AstDatabase,
_id: EagerMacroId,
tt: &tt::Subtree,
) -> ExpandResult<Option<(tt::Subtree, FragmentKind)>> {
let err = match &*tt.token_trees {
[tt::TokenTree::Leaf(tt::Leaf::Literal(it))] => {
let text = it.text.as_str();
if text.starts_with('"') && text.ends_with('"') {
// FIXME: does not handle raw strings
mbe::ExpandError::Other(text[1..text.len() - 1].to_string())
} else {
mbe::ExpandError::BindingError("`compile_error!` argument must be a string".into())
}
}
_ => mbe::ExpandError::BindingError("`compile_error!` argument must be a string".into()),
};
ExpandResult { value: Some((quote! {}, FragmentKind::Items)), err: Some(err) }
}
fn concat_expand(
_db: &dyn AstDatabase,
_arg_id: EagerMacroId,
tt: &tt::Subtree,
) -> ExpandResult<Option<(tt::Subtree, FragmentKind)>> {
let mut err = None;
let mut text = String::new();
for (i, t) in tt.token_trees.iter().enumerate() {
match t {
tt::TokenTree::Leaf(tt::Leaf::Literal(it)) if i % 2 == 0 => {
// concat works with string and char literals, so remove any quotes.
// It also works with integer, float and boolean literals, so just use the rest
// as-is.
let component = unquote_str(&it).unwrap_or_else(|| it.text.to_string());
text.push_str(&component);
}
// handle boolean literals
tt::TokenTree::Leaf(tt::Leaf::Ident(id))
if i % 2 == 0 && (id.text == "true" || id.text == "false") =>
{
text.push_str(id.text.as_str());
}
tt::TokenTree::Leaf(tt::Leaf::Punct(punct)) if i % 2 == 1 && punct.char == ',' => (),
_ => {
err.get_or_insert(mbe::ExpandError::UnexpectedToken);
}
}
}
ExpandResult { value: Some((quote!(#text), FragmentKind::Expr)), err }
}
fn relative_file(
db: &dyn AstDatabase,
call_id: MacroCallId,
path: &str,
allow_recursion: bool,
) -> Option<FileId> {
let call_site = call_id.as_file().original_file(db);
let path = AnchoredPath { anchor: call_site, path };
let res = db.resolve_path(path)?;
// Prevent include itself
if res == call_site && !allow_recursion {
None
} else {
Some(res)
}
}
fn parse_string(tt: &tt::Subtree) -> Result<String, mbe::ExpandError> {
tt.token_trees
.get(0)
.and_then(|tt| match tt {
tt::TokenTree::Leaf(tt::Leaf::Literal(it)) => unquote_str(&it),
_ => None,
})
.ok_or_else(|| mbe::ExpandError::ConversionError)
}
fn include_expand(
db: &dyn AstDatabase,
arg_id: EagerMacroId,
tt: &tt::Subtree,
) -> ExpandResult<Option<(tt::Subtree, FragmentKind)>> {
let res = (|| {
let path = parse_string(tt)?;
let file_id = relative_file(db, arg_id.into(), &path, false)
.ok_or_else(|| mbe::ExpandError::ConversionError)?;
Ok(parse_to_token_tree(&db.file_text(file_id))
.ok_or_else(|| mbe::ExpandError::ConversionError)?
.0)
})();
match res {
Ok(res) => {
// FIXME:
// Handle include as expression
ExpandResult::ok(Some((res, FragmentKind::Items)))
}
Err(e) => ExpandResult::only_err(e),
}
}
fn include_bytes_expand(
_db: &dyn AstDatabase,
_arg_id: EagerMacroId,
tt: &tt::Subtree,
) -> ExpandResult<Option<(tt::Subtree, FragmentKind)>> {
if let Err(e) = parse_string(tt) {
return ExpandResult::only_err(e);
}
// FIXME: actually read the file here if the user asked for macro expansion
let res = tt::Subtree {
delimiter: None,
token_trees: vec![tt::TokenTree::Leaf(tt::Leaf::Literal(tt::Literal {
text: r#"b"""#.into(),
id: tt::TokenId::unspecified(),
}))],
};
ExpandResult::ok(Some((res, FragmentKind::Expr)))
}
fn include_str_expand(
db: &dyn AstDatabase,
arg_id: EagerMacroId,
tt: &tt::Subtree,
) -> ExpandResult<Option<(tt::Subtree, FragmentKind)>> {
let path = match parse_string(tt) {
Ok(it) => it,
Err(e) => return ExpandResult::only_err(e),
};
// FIXME: we're not able to read excluded files (which is most of them because
// it's unusual to `include_str!` a Rust file), but we can return an empty string.
// Ideally, we'd be able to offer a precise expansion if the user asks for macro
// expansion.
let file_id = match relative_file(db, arg_id.into(), &path, true) {
Some(file_id) => file_id,
None => {
return ExpandResult::ok(Some((quote!(""), FragmentKind::Expr)));
}
};
let text = db.file_text(file_id);
let text = &*text;
ExpandResult::ok(Some((quote!(#text), FragmentKind::Expr)))
}
fn get_env_inner(db: &dyn AstDatabase, arg_id: EagerMacroId, key: &str) -> Option<String> {
let krate = db.lookup_intern_eager_expansion(arg_id).krate;
db.crate_graph()[krate].env.get(key)
}
fn env_expand(
db: &dyn AstDatabase,
arg_id: EagerMacroId,
tt: &tt::Subtree,
) -> ExpandResult<Option<(tt::Subtree, FragmentKind)>> {
let key = match parse_string(tt) {
Ok(it) => it,
Err(e) => return ExpandResult::only_err(e),
};
let mut err = None;
let s = get_env_inner(db, arg_id, &key).unwrap_or_else(|| {
// The only variable rust-analyzer ever sets is `OUT_DIR`, so only diagnose that to avoid
// unnecessary diagnostics for eg. `CARGO_PKG_NAME`.
if key == "OUT_DIR" {
err = Some(mbe::ExpandError::Other(
r#"`OUT_DIR` not set, enable "load out dirs from check" to fix"#.into(),
));
}
// If the variable is unset, still return a dummy string to help type inference along.
// We cannot use an empty string here, because for
// `include!(concat!(env!("OUT_DIR"), "/foo.rs"))` will become
// `include!("foo.rs"), which might go to infinite loop
"__RA_UNIMPLEMENTED__".to_string()
});
let expanded = quote! { #s };
ExpandResult { value: Some((expanded, FragmentKind::Expr)), err }
}
fn option_env_expand(
db: &dyn AstDatabase,
arg_id: EagerMacroId,
tt: &tt::Subtree,
) -> ExpandResult<Option<(tt::Subtree, FragmentKind)>> {
let key = match parse_string(tt) {
Ok(it) => it,
Err(e) => return ExpandResult::only_err(e),
};
let expanded = match get_env_inner(db, arg_id, &key) {
None => quote! { std::option::Option::None::<&str> },
Some(s) => quote! { std::option::Some(#s) },
};
ExpandResult::ok(Some((expanded, FragmentKind::Expr)))
}
#[cfg(test)]
mod tests {
use super::*;
use crate::{
name::AsName, test_db::TestDB, AstNode, EagerCallLoc, MacroCallId, MacroCallKind,
MacroCallLoc,
};
use base_db::{fixture::WithFixture, SourceDatabase};
use std::sync::Arc;
use syntax::ast::NameOwner;
fn expand_builtin_macro(ra_fixture: &str) -> String {
let (db, file_id) = TestDB::with_single_file(&ra_fixture);
let parsed = db.parse(file_id);
let mut macro_rules: Vec<_> =
parsed.syntax_node().descendants().filter_map(ast::MacroRules::cast).collect();
let mut macro_calls: Vec<_> =
parsed.syntax_node().descendants().filter_map(ast::MacroCall::cast).collect();
let ast_id_map = db.ast_id_map(file_id.into());
assert_eq!(macro_rules.len(), 1, "test must contain exactly 1 `macro_rules!`");
assert_eq!(macro_calls.len(), 1, "test must contain exactly 1 macro call");
let macro_rules = ast::Macro::from(macro_rules.pop().unwrap());
let macro_call = macro_calls.pop().unwrap();
let expander = find_by_name(&macro_rules.name().unwrap().as_name()).unwrap();
let krate = CrateId(0);
let file_id = match expander {
Either::Left(expander) => {
// the first one should be a macro_rules
let def = MacroDefId {
krate: CrateId(0),
ast_id: Some(AstId::new(file_id.into(), ast_id_map.ast_id(&macro_rules))),
kind: MacroDefKind::BuiltIn(expander),
local_inner: false,
};
let loc = MacroCallLoc {
def,
krate,
kind: MacroCallKind::FnLike(AstId::new(
file_id.into(),
ast_id_map.ast_id(&macro_call),
)),
};
let id: MacroCallId = db.intern_macro(loc).into();
id.as_file()
}
Either::Right(expander) => {
// the first one should be a macro_rules
let def = MacroDefId {
krate,
ast_id: Some(AstId::new(file_id.into(), ast_id_map.ast_id(&macro_rules))),
kind: MacroDefKind::BuiltInEager(expander),
local_inner: false,
};
let args = macro_call.token_tree().unwrap();
let parsed_args = mbe::ast_to_token_tree(&args).unwrap().0;
let call_id = AstId::new(file_id.into(), ast_id_map.ast_id(&macro_call));
let arg_id = db.intern_eager_expansion({
EagerCallLoc {
def,
fragment: FragmentKind::Expr,
subtree: Arc::new(parsed_args.clone()),
krate,
call: call_id,
}
});
let (subtree, fragment) = expander.expand(&db, arg_id, &parsed_args).value.unwrap();
let eager = EagerCallLoc {
def,
fragment,
subtree: Arc::new(subtree),
krate,
call: call_id,
};
let id: MacroCallId = db.intern_eager_expansion(eager).into();
id.as_file()
}
};
db.parse_or_expand(file_id).unwrap().to_string()
}
#[test]
fn test_column_expand() {
let expanded = expand_builtin_macro(
r#"
#[rustc_builtin_macro]
macro_rules! column {() => {}}
column!()
"#,
);
assert_eq!(expanded, "0");
}
#[test]
fn test_line_expand() {
let expanded = expand_builtin_macro(
r#"
#[rustc_builtin_macro]
macro_rules! line {() => {}}
line!()
"#,
);
assert_eq!(expanded, "0");
}
#[test]
fn test_stringify_expand() {
let expanded = expand_builtin_macro(
r#"
#[rustc_builtin_macro]
macro_rules! stringify {() => {}}
stringify!(a b c)
"#,
);
assert_eq!(expanded, "\"a b c\"");
}
#[test]
fn test_env_expand() {
let expanded = expand_builtin_macro(
r#"
#[rustc_builtin_macro]
macro_rules! env {() => {}}
env!("TEST_ENV_VAR")
"#,
);
assert_eq!(expanded, "\"__RA_UNIMPLEMENTED__\"");
}
#[test]
fn test_option_env_expand() {
let expanded = expand_builtin_macro(
r#"
#[rustc_builtin_macro]
macro_rules! option_env {() => {}}
option_env!("TEST_ENV_VAR")
"#,
);
assert_eq!(expanded, "std::option::Option::None:: < &str>");
}
#[test]
fn test_file_expand() {
let expanded = expand_builtin_macro(
r#"
#[rustc_builtin_macro]
macro_rules! file {() => {}}
file!()
"#,
);
assert_eq!(expanded, "\"\"");
}
#[test]
fn test_assert_expand() {
let expanded = expand_builtin_macro(
r#"
#[rustc_builtin_macro]
macro_rules! assert {
($cond:expr) => ({ /* compiler built-in */ });
($cond:expr, $($args:tt)*) => ({ /* compiler built-in */ })
}
assert!(true, "{} {:?}", arg1(a, b, c), arg2);
"#,
);
assert_eq!(expanded, "{{(&(true), &(\"{} {:?}\"), &(arg1(a,b,c)), &(arg2),);}}");
}
#[test]
fn test_compile_error_expand() {
let expanded = expand_builtin_macro(
r#"
#[rustc_builtin_macro]
macro_rules! compile_error {
($msg:expr) => ({ /* compiler built-in */ });
($msg:expr,) => ({ /* compiler built-in */ })
}
compile_error!("error!");
"#,
);
// This expands to nothing (since it's in item position), but emits an error.
assert_eq!(expanded, "");
}
#[test]
fn test_format_args_expand() {
let expanded = expand_builtin_macro(
r#"
#[rustc_builtin_macro]
macro_rules! format_args {
($fmt:expr) => ({ /* compiler built-in */ });
($fmt:expr, $($args:tt)*) => ({ /* compiler built-in */ })
}
format_args!("{} {:?}", arg1(a, b, c), arg2);
"#,
);
assert_eq!(
expanded,
r#"std::fmt::Arguments::new_v1(&[], &[std::fmt::ArgumentV1::new(&(arg1(a,b,c)),std::fmt::Display::fmt),std::fmt::ArgumentV1::new(&(arg2),std::fmt::Display::fmt),])"#
);
}
#[test]
fn test_include_bytes_expand() {
let expanded = expand_builtin_macro(
r#"
#[rustc_builtin_macro]
macro_rules! include_bytes {
($file:expr) => {{ /* compiler built-in */ }};
($file:expr,) => {{ /* compiler built-in */ }};
}
include_bytes("foo");
"#,
);
assert_eq!(expanded, r#"b"""#);
}
#[test]
fn test_concat_expand() {
let expanded = expand_builtin_macro(
r##"
#[rustc_builtin_macro]
macro_rules! concat {}
concat!("foo", "r", 0, r#"bar"#, false);
"##,
);
assert_eq!(expanded, r#""foor0barfalse""#);
}
}