Auto merge of #85993 - bjorn3:serde_json, r=wesleywiser

Remove all json handling from rustc_serialize

Json is now handled using serde_json. Where appropriate I have replaced json usage with binary serialization (rmeta files) or manual string formatting (emcc linker arg generation).

This allowed for removing and simplifying a lot of code, which hopefully results in faster serialization/deserialization and faster compiles of rustc itself.

Where sensible we now use serde. Metadata and incr cache serialization keeps using a heavily modified (compared to crates.io) rustc-serialize version that in the future could probably be extended with zero-copy deserialization or other perf tricks that serde can't support due to supporting more than one serialization format.

Note that I had to remove `-Zast-json` and `-Zast-json-noexpand` as the relevant AST types don't implement `serde::Serialize`.

Fixes #40177

See also https://github.com/rust-lang/compiler-team/issues/418

9 files changed, 111 insertions, 113 deletions

diff --git a/src/test/ui-fulldeps/extern-mod-syntax.rs b/src/test/ui-fulldeps/extern-mod-syntax.rs
index a90ab7ac438..230194c5377 100644
--- a/src/test/ui-fulldeps/extern-mod-syntax.rs
+++ b/src/test/ui-fulldeps/extern-mod-syntax.rs
@@ -3,8 +3,8 @@
 #![allow(unused_imports)]
 #![feature(rustc_private)]
 
-extern crate rustc_serialize;
-use rustc_serialize::json::Object;
+extern crate libc;
+use libc::c_void;
 
 pub fn main() {
     println!("Hello world!");
diff --git a/src/test/ui-fulldeps/issue-11881.rs b/src/test/ui-fulldeps/issue-11881.rs
index 6d64aeeda7e..9641470a68b 100644
--- a/src/test/ui-fulldeps/issue-11881.rs
+++ b/src/test/ui-fulldeps/issue-11881.rs
@@ -3,42 +3,80 @@
 #![allow(unused_must_use)]
 #![allow(dead_code)]
 #![allow(unused_imports)]
-#![feature(rustc_private)]
-
-extern crate rustc_macros;
-extern crate rustc_serialize;
 
 use std::fmt;
 use std::io::prelude::*;
 use std::io::Cursor;
 use std::slice;
+use std::marker::PhantomData;
+
+trait Encoder {
+    type Error;
+}
+
+trait Encodable<S: Encoder> {
+    fn encode(&self, s: &mut S) -> Result<(), S::Error>;
+}
+
+struct JsonEncoder<'a>(PhantomData<&'a mut ()>);
+
+impl Encoder for JsonEncoder<'_> {
+    type Error = ();
+}
+
+struct AsJson<'a, T> {
+    inner: &'a T,
+}
+
+impl<'a, T: for<'r> Encodable<JsonEncoder<'r>>> fmt::Display for AsJson<'a, T> {
+    /// Encodes a json value into a string
+    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        Ok(())
+    }
+}
+
+fn as_json<T>(t: &T) -> AsJson<'_, T> {
+    AsJson { inner: t }
+}
+
+struct OpaqueEncoder(Vec<u8>);
+
+impl Encoder for OpaqueEncoder {
+    type Error = ();
+}
 
-use rustc_macros::Encodable;
-use rustc_serialize::json;
-use rustc_serialize::opaque;
-use rustc_serialize::{Encodable, Encoder};
 
-#[derive(Encodable)]
 struct Foo {
     baz: bool,
 }
 
-#[derive(Encodable)]
+impl<S: Encoder> Encodable<S> for Foo {
+    fn encode(&self, _s: &mut S) -> Result<(), S::Error> {
+        Ok(())
+    }
+}
+
 struct Bar {
     froboz: usize,
 }
 
+impl<S: Encoder> Encodable<S> for Bar {
+    fn encode(&self, _s: &mut S) -> Result<(), S::Error> {
+        Ok(())
+    }
+}
+
 enum WireProtocol {
     JSON,
     Opaque,
     // ...
 }
 
-fn encode_json<T: for<'a> Encodable<json::Encoder<'a>>>(val: &T, wr: &mut Cursor<Vec<u8>>) {
-    write!(wr, "{}", json::as_json(val));
+fn encode_json<T: for<'a> Encodable<JsonEncoder<'a>>>(val: &T, wr: &mut Cursor<Vec<u8>>) {
+    write!(wr, "{}", as_json(val));
 }
-fn encode_opaque<T: Encodable<opaque::Encoder>>(val: &T, wr: Vec<u8>) {
-    let mut encoder = opaque::Encoder::new(wr);
+fn encode_opaque<T: Encodable<OpaqueEncoder>>(val: &T, wr: Vec<u8>) {
+    let mut encoder = OpaqueEncoder(wr);
     val.encode(&mut encoder);
 }
 
diff --git a/src/test/ui-fulldeps/issue-15924.rs b/src/test/ui-fulldeps/issue-15924.rs
index 5adc2c482f5..d8b3914d0d4 100644
--- a/src/test/ui-fulldeps/issue-15924.rs
+++ b/src/test/ui-fulldeps/issue-15924.rs
@@ -3,21 +3,48 @@
 #![allow(unused_imports)]
 #![allow(unused_must_use)]
 // pretty-expanded FIXME #23616
-#![feature(rustc_private)]
 
-extern crate rustc_serialize;
-
-use rustc_serialize::json;
-use rustc_serialize::{Encodable, Encoder};
 use std::fmt;
+use std::marker::PhantomData;
+
+trait Encoder {
+    type Error;
+}
+
+trait Encodable<S: Encoder> {
+    fn encode(&self, s: &mut S) -> Result<(), S::Error>;
+}
+
+impl<S: Encoder> Encodable<S> for i32 {
+    fn encode(&self, _s: &mut S) -> Result<(), S::Error> {
+        Ok(())
+    }
+}
+
+struct JsonEncoder<'a>(PhantomData<&'a mut ()>);
+
+impl Encoder for JsonEncoder<'_> {
+    type Error = ();
+}
+
+fn encode_json<T: for<'r> Encodable<JsonEncoder<'r>>>(
+    object: &T,
+) -> Result<String, ()> {
+    let s = String::new();
+    {
+        let mut encoder = JsonEncoder(PhantomData);
+        object.encode(&mut encoder)?;
+    }
+    Ok(s)
+}
 
-struct Foo<T: for<'a> Encodable<json::Encoder<'a>>> {
+struct Foo<T: for<'a> Encodable<JsonEncoder<'a>>> {
     v: T,
 }
 
-impl<T: for<'a> Encodable<json::Encoder<'a>>> Drop for Foo<T> {
+impl<T: for<'a> Encodable<JsonEncoder<'a>>> Drop for Foo<T> {
     fn drop(&mut self) {
-        json::encode(&self.v);
+        encode_json(&self.v);
     }
 }
 
diff --git a/src/test/ui-fulldeps/issue-2804.rs b/src/test/ui-fulldeps/issue-2804.rs
index 3d5922d155f..571028c5e40 100644
--- a/src/test/ui-fulldeps/issue-2804.rs
+++ b/src/test/ui-fulldeps/issue-2804.rs
@@ -2,27 +2,38 @@
 
 #![allow(non_camel_case_types)]
 #![allow(dead_code)]
-#![feature(rustc_private)]
 
-extern crate rustc_serialize;
-
-use std::collections::HashMap;
-use rustc_serialize::json::{self, Json};
+use std::collections::{BTreeMap, HashMap};
 use std::option;
 
+#[derive(Clone, Debug)]
+enum Json {
+    I64(i64),
+    U64(u64),
+    F64(f64),
+    String(String),
+    Boolean(bool),
+    Array(Array),
+    Object(Object),
+    Null,
+}
+
+type Array = Vec<Json>;
+type Object = BTreeMap<String, Json>;
+
 enum object {
     bool_value(bool),
     int_value(i64),
 }
 
-fn lookup(table: json::Object, key: String, default: String) -> String
+fn lookup(table: Object, key: String, default: String) -> String
 {
     match table.get(&key) {
         option::Option::Some(&Json::String(ref s)) => {
             s.to_string()
         }
         option::Option::Some(value) => {
-            println!("{} was expected to be a string but is a {}", key, value);
+            println!("{} was expected to be a string but is a {:?}", key, value);
             default
         }
         option::Option::None => {
@@ -31,7 +42,7 @@ fn lookup(table: json::Object, key: String, default: String) -> String
     }
 }
 
-fn add_interface(_store: isize, managed_ip: String, data: json::Json) -> (String, object)
+fn add_interface(_store: isize, managed_ip: String, data: Json) -> (String, object)
 {
     match &data {
         &Json::Object(ref interface) => {
@@ -43,13 +54,13 @@ fn add_interface(_store: isize, managed_ip: String, data: json::Json) -> (String
             (label, object::bool_value(false))
         }
         _ => {
-            println!("Expected dict for {} interfaces, found {}", managed_ip, data);
+            println!("Expected dict for {} interfaces, found {:?}", managed_ip, data);
             ("gnos:missing-interface".to_string(), object::bool_value(true))
         }
     }
 }
 
-fn add_interfaces(store: isize, managed_ip: String, device: HashMap<String, json::Json>)
+fn add_interfaces(store: isize, managed_ip: String, device: HashMap<String, Json>)
 -> Vec<(String, object)> {
     match device["interfaces"] {
         Json::Array(ref interfaces) =>
@@ -60,7 +71,7 @@ fn add_interfaces(store: isize, managed_ip: String, device: HashMap<String, json
         }
         _ =>
         {
-            println!("Expected list for {} interfaces, found {}", managed_ip,
+            println!("Expected list for {} interfaces, found {:?}", managed_ip,
                      device["interfaces"]);
             Vec::new()
         }
diff --git a/src/test/ui/ast-json/ast-json-ice.rs b/src/test/ui/ast-json/ast-json-ice.rs
deleted file mode 100644
index ce93e4b5d4b..00000000000
--- a/src/test/ui/ast-json/ast-json-ice.rs
+++ /dev/null
@@ -1,56 +0,0 @@
-// Test that AST json serialization doesn't ICE (#63728).
-
-// revisions: expand noexpand
-
-//[expand] compile-flags: -Zast-json
-//[noexpand] compile-flags: -Zast-json-noexpand
-
-// check-pass
-// dont-check-compiler-stdout - don't check for any AST change.
-
-enum V {
-    A(i32),
-    B { f: [i64; 3 + 4] }
-}
-
-trait X {
-    type Output;
-    fn read(&self) -> Self::Output;
-    fn write(&mut self, _: Self::Output);
-}
-
-macro_rules! call_println {
-    ($y:ident) => { println!("{}", $y) }
-}
-
-fn main() {
-    let x: (i32) = 35;
-    let y = x as i64<> + 5;
-
-    call_println!(y);
-
-    struct A;
-}
-
-// Regressions tests for issues #78398 and #78510 (captured tokens in associated and foreign items)
-
-struct S;
-
-macro_rules! mac_extern {
-    ($i:item) => {
-        extern "C" { $i }
-    }
-}
-macro_rules! mac_assoc {
-    ($i:item) => {
-        impl S { $i }
-        trait Bar { $i }
-    }
-}
-
-mac_extern! {
-    fn foo();
-}
-mac_assoc! {
-    fn foo() {}
-}
diff --git a/src/test/ui/ast-json/ast-json-noexpand-output.rs b/src/test/ui/ast-json/ast-json-noexpand-output.rs
deleted file mode 100644
index cba539f0065..00000000000
--- a/src/test/ui/ast-json/ast-json-noexpand-output.rs
+++ /dev/null
@@ -1,10 +0,0 @@
-// Check that AST json printing works.
-#![crate_type = "lib"]
-
-// check-pass
-// compile-flags: -Zast-json-noexpand
-// normalize-stdout-test ":\d+" -> ":0"
-
-// Only include a single item to reduce how often the test output needs
-// updating.
-extern crate core;
diff --git a/src/test/ui/ast-json/ast-json-noexpand-output.stdout b/src/test/ui/ast-json/ast-json-noexpand-output.stdout
deleted file mode 100644
index 6f6e9b38e94..00000000000
--- a/src/test/ui/ast-json/ast-json-noexpand-output.stdout
+++ /dev/null
@@ -1 +0,0 @@
-{"attrs":[{"kind":{"variant":"Normal","fields":[{"path":{"span":{"lo":0,"hi":0},"segments":[{"ident":{"name":"crate_type","span":{"lo":0,"hi":0}},"id":0,"args":null}],"tokens":null},"args":{"variant":"Eq","fields":[{"lo":0,"hi":0},{"variant":"Ast","fields":[{"id":0,"kind":{"variant":"Lit","fields":[{"token":{"kind":"Str","symbol":"lib","suffix":null},"kind":{"variant":"Str","fields":["lib","Cooked"]},"span":{"lo":0,"hi":0}}]},"span":{"lo":0,"hi":0},"attrs":{"0":null},"tokens":{"0":[[{"variant":"Token","fields":[{"kind":{"variant":"Literal","fields":[{"kind":"Str","symbol":"lib","suffix":null}]},"span":{"lo":0,"hi":0}}]},"Alone"]]}}]}]},"tokens":null},{"0":[[{"variant":"Token","fields":[{"kind":"Pound","span":{"lo":0,"hi":0}}]},"Joint"],[{"variant":"Token","fields":[{"kind":"Not","span":{"lo":0,"hi":0}}]},"Alone"],[{"variant":"Delimited","fields":[{"open":{"lo":0,"hi":0},"close":{"lo":0,"hi":0}},"Bracket",{"0":[[{"variant":"Token","fields":[{"kind":{"variant":"Ident","fields":["crate_type",false]},"span":{"lo":0,"hi":0}}]},"Alone"],[{"variant":"Token","fields":[{"kind":"Eq","span":{"lo":0,"hi":0}}]},"Alone"],[{"variant":"Token","fields":[{"kind":{"variant":"Literal","fields":[{"kind":"Str","symbol":"lib","suffix":null}]},"span":{"lo":0,"hi":0}}]},"Alone"]]}]},"Alone"]]}]},"id":null,"style":"Inner","span":{"lo":0,"hi":0}}],"items":[{"attrs":[],"id":0,"span":{"lo":0,"hi":0},"vis":{"kind":"Inherited","span":{"lo":0,"hi":0},"tokens":null},"ident":{"name":"core","span":{"lo":0,"hi":0}},"kind":{"variant":"ExternCrate","fields":[null]},"tokens":null}],"spans":{"inner_span":{"lo":0,"hi":0},"inject_use_span":{"lo":0,"hi":0}},"id":0,"is_placeholder":false}
diff --git a/src/test/ui/ast-json/ast-json-output.rs b/src/test/ui/ast-json/ast-json-output.rs
deleted file mode 100644
index 2e009149ed6..00000000000
--- a/src/test/ui/ast-json/ast-json-output.rs
+++ /dev/null
@@ -1,10 +0,0 @@
-// Check that AST json printing works.
-#![crate_type = "lib"]
-
-// check-pass
-// compile-flags: -Zast-json
-// normalize-stdout-test ":\d+" -> ":0"
-
-// Only include a single item to reduce how often the test output needs
-// updating.
-extern crate core;
diff --git a/src/test/ui/ast-json/ast-json-output.stdout b/src/test/ui/ast-json/ast-json-output.stdout
deleted file mode 100644
index 5637ce596b3..00000000000
--- a/src/test/ui/ast-json/ast-json-output.stdout
+++ /dev/null
@@ -1 +0,0 @@
-{"attrs":[{"kind":{"variant":"Normal","fields":[{"path":{"span":{"lo":0,"hi":0},"segments":[{"ident":{"name":"crate_type","span":{"lo":0,"hi":0}},"id":0,"args":null}],"tokens":null},"args":{"variant":"Eq","fields":[{"lo":0,"hi":0},{"variant":"Ast","fields":[{"id":0,"kind":{"variant":"Lit","fields":[{"token":{"kind":"Str","symbol":"lib","suffix":null},"kind":{"variant":"Str","fields":["lib","Cooked"]},"span":{"lo":0,"hi":0}}]},"span":{"lo":0,"hi":0},"attrs":{"0":null},"tokens":{"0":[[{"variant":"Token","fields":[{"kind":{"variant":"Literal","fields":[{"kind":"Str","symbol":"lib","suffix":null}]},"span":{"lo":0,"hi":0}}]},"Alone"]]}}]}]},"tokens":null},{"0":[[{"variant":"Token","fields":[{"kind":"Pound","span":{"lo":0,"hi":0}}]},"Joint"],[{"variant":"Token","fields":[{"kind":"Not","span":{"lo":0,"hi":0}}]},"Alone"],[{"variant":"Delimited","fields":[{"open":{"lo":0,"hi":0},"close":{"lo":0,"hi":0}},"Bracket",{"0":[[{"variant":"Token","fields":[{"kind":{"variant":"Ident","fields":["crate_type",false]},"span":{"lo":0,"hi":0}}]},"Alone"],[{"variant":"Token","fields":[{"kind":"Eq","span":{"lo":0,"hi":0}}]},"Alone"],[{"variant":"Token","fields":[{"kind":{"variant":"Literal","fields":[{"kind":"Str","symbol":"lib","suffix":null}]},"span":{"lo":0,"hi":0}}]},"Alone"]]}]},"Alone"]]}]},"id":null,"style":"Inner","span":{"lo":0,"hi":0}}],"items":[{"attrs":[{"kind":{"variant":"Normal","fields":[{"path":{"span":{"lo":0,"hi":0},"segments":[{"ident":{"name":"prelude_import","span":{"lo":0,"hi":0}},"id":0,"args":null}],"tokens":null},"args":"Empty","tokens":null},null]},"id":null,"style":"Outer","span":{"lo":0,"hi":0}}],"id":0,"span":{"lo":0,"hi":0},"vis":{"kind":"Inherited","span":{"lo":0,"hi":0},"tokens":null},"ident":{"name":"","span":{"lo":0,"hi":0}},"kind":{"variant":"Use","fields":[{"prefix":{"span":{"lo":0,"hi":0},"segments":[{"ident":{"name":"{{root}}","span":{"lo":0,"hi":0}},"id":0,"args":null},{"ident":{"name":"std","span":{"lo":0,"hi":0}},"id":0,"args":null},{"ident":{"name":"prelude","span":{"lo":0,"hi":0}},"id":0,"args":null},{"ident":{"name":"rust_2015","span":{"lo":0,"hi":0}},"id":0,"args":null}],"tokens":null},"kind":"Glob","span":{"lo":0,"hi":0}}]},"tokens":null},{"attrs":[{"kind":{"variant":"Normal","fields":[{"path":{"span":{"lo":0,"hi":0},"segments":[{"ident":{"name":"macro_use","span":{"lo":0,"hi":0}},"id":0,"args":null}],"tokens":null},"args":"Empty","tokens":null},null]},"id":null,"style":"Outer","span":{"lo":0,"hi":0}}],"id":0,"span":{"lo":0,"hi":0},"vis":{"kind":"Inherited","span":{"lo":0,"hi":0},"tokens":null},"ident":{"name":"std","span":{"lo":0,"hi":0}},"kind":{"variant":"ExternCrate","fields":[null]},"tokens":null},{"attrs":[],"id":0,"span":{"lo":0,"hi":0},"vis":{"kind":"Inherited","span":{"lo":0,"hi":0},"tokens":null},"ident":{"name":"core","span":{"lo":0,"hi":0}},"kind":{"variant":"ExternCrate","fields":[null]},"tokens":null}],"spans":{"inner_span":{"lo":0,"hi":0},"inject_use_span":{"lo":0,"hi":0}},"id":0,"is_placeholder":false}