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1// SPDX-License-Identifier: GPL-2.0
2
3//! The custom target specification file generator for `rustc`.
4//!
5//! To configure a target from scratch, a JSON-encoded file has to be passed
6//! to `rustc` (introduced in [RFC 131]). These options and the file itself are
7//! unstable. Eventually, `rustc` should provide a way to do this in a stable
8//! manner. For instance, via command-line arguments. Therefore, this file
9//! should avoid using keys which can be set via `-C` or `-Z` options.
10//!
11//! [RFC 131]: https://rust-lang.github.io/rfcs/0131-target-specification.html
12
13use std::{
14 collections::HashMap,
15 fmt::{Display, Formatter, Result},
16 io::BufRead,
17};
18
19enum Value {
20 Boolean(bool),
21 Number(i32),
22 String(String),
23 Object(Object),
24}
25
26type Object = Vec<(String, Value)>;
27
28/// Minimal "almost JSON" generator (e.g. no `null`s, no arrays, no escaping),
29/// enough for this purpose.
30impl Display for Value {
31 fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
32 match self {
33 Value::Boolean(boolean) => write!(formatter, "{}", boolean),
34 Value::Number(number) => write!(formatter, "{}", number),
35 Value::String(string) => write!(formatter, "\"{}\"", string),
36 Value::Object(object) => {
37 formatter.write_str("{")?;
38 if let [ref rest @ .., ref last] = object[..] {
39 for (key, value) in rest {
40 write!(formatter, "\"{}\": {},", key, value)?;
41 }
42 write!(formatter, "\"{}\": {}", last.0, last.1)?;
43 }
44 formatter.write_str("}")
45 }
46 }
47 }
48}
49
50struct TargetSpec(Object);
51
52impl TargetSpec {
53 fn new() -> TargetSpec {
54 TargetSpec(Vec::new())
55 }
56}
57
58trait Push<T> {
59 fn push(&mut self, key: &str, value: T);
60}
61
62impl Push<bool> for TargetSpec {
63 fn push(&mut self, key: &str, value: bool) {
64 self.0.push((key.to_string(), Value::Boolean(value)));
65 }
66}
67
68impl Push<i32> for TargetSpec {
69 fn push(&mut self, key: &str, value: i32) {
70 self.0.push((key.to_string(), Value::Number(value)));
71 }
72}
73
74impl Push<String> for TargetSpec {
75 fn push(&mut self, key: &str, value: String) {
76 self.0.push((key.to_string(), Value::String(value)));
77 }
78}
79
80impl Push<&str> for TargetSpec {
81 fn push(&mut self, key: &str, value: &str) {
82 self.push(key, value.to_string());
83 }
84}
85
86impl Push<Object> for TargetSpec {
87 fn push(&mut self, key: &str, value: Object) {
88 self.0.push((key.to_string(), Value::Object(value)));
89 }
90}
91
92impl Display for TargetSpec {
93 fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
94 // We add some newlines for clarity.
95 formatter.write_str("{\n")?;
96 if let [ref rest @ .., ref last] = self.0[..] {
97 for (key, value) in rest {
98 write!(formatter, " \"{}\": {},\n", key, value)?;
99 }
100 write!(formatter, " \"{}\": {}\n", last.0, last.1)?;
101 }
102 formatter.write_str("}")
103 }
104}
105
106struct KernelConfig(HashMap<String, String>);
107
108impl KernelConfig {
109 /// Parses `include/config/auto.conf` from `stdin`.
110 fn from_stdin() -> KernelConfig {
111 let mut result = HashMap::new();
112
113 let stdin = std::io::stdin();
114 let mut handle = stdin.lock();
115 let mut line = String::new();
116
117 loop {
118 line.clear();
119
120 if handle.read_line(&mut line).unwrap() == 0 {
121 break;
122 }
123
124 if line.starts_with('#') {
125 continue;
126 }
127
128 let (key, value) = line.split_once('=').expect("Missing `=` in line.");
129 result.insert(key.to_string(), value.trim_end_matches('\n').to_string());
130 }
131
132 KernelConfig(result)
133 }
134
135 /// Does the option exist in the configuration (any value)?
136 ///
137 /// The argument must be passed without the `CONFIG_` prefix.
138 /// This avoids repetition and it also avoids `fixdep` making us
139 /// depend on it.
140 fn has(&self, option: &str) -> bool {
141 let option = "CONFIG_".to_owned() + option;
142 self.0.contains_key(&option)
143 }
144}
145
146fn main() {
147 let cfg = KernelConfig::from_stdin();
148 let mut ts = TargetSpec::new();
149
150 // `llvm-target`s are taken from `scripts/Makefile.clang`.
151 if cfg.has("X86_64") {
152 ts.push("arch", "x86_64");
153 ts.push(
154 "data-layout",
155 "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128",
156 );
157 let mut features = "-3dnow,-3dnowa,-mmx,+soft-float".to_string();
158 if cfg.has("RETPOLINE") {
159 features += ",+retpoline-external-thunk";
160 }
161 ts.push("features", features);
162 ts.push("llvm-target", "x86_64-linux-gnu");
163 ts.push("target-pointer-width", "64");
164 } else if cfg.has("LOONGARCH") {
165 ts.push("arch", "loongarch64");
166 ts.push("data-layout", "e-m:e-p:64:64-i64:64-i128:128-n64-S128");
167 ts.push("features", "-f,-d");
168 ts.push("llvm-target", "loongarch64-linux-gnusf");
169 ts.push("llvm-abiname", "lp64s");
170 ts.push("target-pointer-width", "64");
171 } else {
172 panic!("Unsupported architecture");
173 }
174
175 ts.push("emit-debug-gdb-scripts", false);
176 ts.push("frame-pointer", "may-omit");
177 ts.push(
178 "stack-probes",
179 vec![("kind".to_string(), Value::String("none".to_string()))],
180 );
181
182 // Everything else is LE, whether `CPU_LITTLE_ENDIAN` is declared or not
183 // (e.g. x86). It is also `rustc`'s default.
184 if cfg.has("CPU_BIG_ENDIAN") {
185 ts.push("target-endian", "big");
186 }
187
188 println!("{}", ts);
189}
1// SPDX-License-Identifier: GPL-2.0
2
3//! The custom target specification file generator for `rustc`.
4//!
5//! To configure a target from scratch, a JSON-encoded file has to be passed
6//! to `rustc` (introduced in [RFC 131]). These options and the file itself are
7//! unstable. Eventually, `rustc` should provide a way to do this in a stable
8//! manner. For instance, via command-line arguments. Therefore, this file
9//! should avoid using keys which can be set via `-C` or `-Z` options.
10//!
11//! [RFC 131]: https://rust-lang.github.io/rfcs/0131-target-specification.html
12
13use std::{
14 collections::HashMap,
15 fmt::{Display, Formatter, Result},
16 io::BufRead,
17};
18
19enum Value {
20 Boolean(bool),
21 Number(i32),
22 String(String),
23 Object(Object),
24}
25
26type Object = Vec<(String, Value)>;
27
28/// Minimal "almost JSON" generator (e.g. no `null`s, no arrays, no escaping),
29/// enough for this purpose.
30impl Display for Value {
31 fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
32 match self {
33 Value::Boolean(boolean) => write!(formatter, "{}", boolean),
34 Value::Number(number) => write!(formatter, "{}", number),
35 Value::String(string) => write!(formatter, "\"{}\"", string),
36 Value::Object(object) => {
37 formatter.write_str("{")?;
38 if let [ref rest @ .., ref last] = object[..] {
39 for (key, value) in rest {
40 write!(formatter, "\"{}\": {},", key, value)?;
41 }
42 write!(formatter, "\"{}\": {}", last.0, last.1)?;
43 }
44 formatter.write_str("}")
45 }
46 }
47 }
48}
49
50struct TargetSpec(Object);
51
52impl TargetSpec {
53 fn new() -> TargetSpec {
54 TargetSpec(Vec::new())
55 }
56}
57
58trait Push<T> {
59 fn push(&mut self, key: &str, value: T);
60}
61
62impl Push<bool> for TargetSpec {
63 fn push(&mut self, key: &str, value: bool) {
64 self.0.push((key.to_string(), Value::Boolean(value)));
65 }
66}
67
68impl Push<i32> for TargetSpec {
69 fn push(&mut self, key: &str, value: i32) {
70 self.0.push((key.to_string(), Value::Number(value)));
71 }
72}
73
74impl Push<String> for TargetSpec {
75 fn push(&mut self, key: &str, value: String) {
76 self.0.push((key.to_string(), Value::String(value)));
77 }
78}
79
80impl Push<&str> for TargetSpec {
81 fn push(&mut self, key: &str, value: &str) {
82 self.push(key, value.to_string());
83 }
84}
85
86impl Push<Object> for TargetSpec {
87 fn push(&mut self, key: &str, value: Object) {
88 self.0.push((key.to_string(), Value::Object(value)));
89 }
90}
91
92impl Display for TargetSpec {
93 fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
94 // We add some newlines for clarity.
95 formatter.write_str("{\n")?;
96 if let [ref rest @ .., ref last] = self.0[..] {
97 for (key, value) in rest {
98 write!(formatter, " \"{}\": {},\n", key, value)?;
99 }
100 write!(formatter, " \"{}\": {}\n", last.0, last.1)?;
101 }
102 formatter.write_str("}")
103 }
104}
105
106struct KernelConfig(HashMap<String, String>);
107
108impl KernelConfig {
109 /// Parses `include/config/auto.conf` from `stdin`.
110 fn from_stdin() -> KernelConfig {
111 let mut result = HashMap::new();
112
113 let stdin = std::io::stdin();
114 let mut handle = stdin.lock();
115 let mut line = String::new();
116
117 loop {
118 line.clear();
119
120 if handle.read_line(&mut line).unwrap() == 0 {
121 break;
122 }
123
124 if line.starts_with('#') {
125 continue;
126 }
127
128 let (key, value) = line.split_once('=').expect("Missing `=` in line.");
129 result.insert(key.to_string(), value.trim_end_matches('\n').to_string());
130 }
131
132 KernelConfig(result)
133 }
134
135 /// Does the option exist in the configuration (any value)?
136 ///
137 /// The argument must be passed without the `CONFIG_` prefix.
138 /// This avoids repetition and it also avoids `fixdep` making us
139 /// depend on it.
140 fn has(&self, option: &str) -> bool {
141 let option = "CONFIG_".to_owned() + option;
142 self.0.contains_key(&option)
143 }
144}
145
146fn main() {
147 let cfg = KernelConfig::from_stdin();
148 let mut ts = TargetSpec::new();
149
150 // `llvm-target`s are taken from `scripts/Makefile.clang`.
151 if cfg.has("X86_64") {
152 ts.push("arch", "x86_64");
153 ts.push(
154 "data-layout",
155 "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128",
156 );
157 let mut features = "-3dnow,-3dnowa,-mmx,+soft-float".to_string();
158 if cfg.has("RETPOLINE") {
159 features += ",+retpoline-external-thunk";
160 }
161 ts.push("features", features);
162 ts.push("llvm-target", "x86_64-linux-gnu");
163 ts.push("target-pointer-width", "64");
164 } else {
165 panic!("Unsupported architecture");
166 }
167
168 ts.push("emit-debug-gdb-scripts", false);
169 ts.push("frame-pointer", "may-omit");
170 ts.push(
171 "stack-probes",
172 vec![("kind".to_string(), Value::String("none".to_string()))],
173 );
174
175 // Everything else is LE, whether `CPU_LITTLE_ENDIAN` is declared or not
176 // (e.g. x86). It is also `rustc`'s default.
177 if cfg.has("CPU_BIG_ENDIAN") {
178 ts.push("target-endian", "big");
179 }
180
181 println!("{}", ts);
182}