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

1 files changed, 0 insertions, 4 deletions

diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index 66198dff2ae..ae32fd2dee9 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -1207,10 +1207,6 @@ options! {
     assert_incr_state: Option<String> = (None, parse_opt_string, [UNTRACKED],
         "assert that the incremental cache is in given state: \
          either `loaded` or `not-loaded`."),
-    ast_json: bool = (false, parse_bool, [UNTRACKED],
-        "print the AST as JSON and halt (default: no)"),
-    ast_json_noexpand: bool = (false, parse_bool, [UNTRACKED],
-        "print the pre-expansion AST as JSON and halt (default: no)"),
     binary_dep_depinfo: bool = (false, parse_bool, [TRACKED],
         "include artifacts (sysroot, crate dependencies) used during compilation in dep-info \
         (default: no)"),