Build with -Zannotate-moves by default

Build rustc and tools with -Zannotate-moves by default. Adds toml config
options to set the annotation size limit.

This has no measurable effect on output binary size or compile time.

Author: Jeremy Fitzhardinge

bootstrap.example.toml

@@ -828,6 +828,10 @@
 # If an explicit setting is given, it will be used for all parts of the codebase.
 #rust.new-symbol-mangling = true|false (see comment)
 
+# Size limit in bytes for move/copy annotations. Only types at or above this size will
+# be annotated. If not specified, uses the default limit (65 bytes).
+#rust.annotate-moves-size-limit = 65
+
 # Select LTO mode that will be used for compiling rustc. By default, thin local LTO
 # (LTO within a single crate) is used (like for any Rust crate). You can also select
 # "thin" or "fat" to apply Thin/Fat LTO to the `rustc_driver` dylib, or "off" to disable

src/bootstrap/src/core/builder/cargo.rs

@@ -654,6 +654,13 @@ impl Builder<'_> {
             rustflags.arg("-Csymbol-mangling-version=legacy");
         }
 
+        // Always enable move/copy annotations for profiler visibility
+        if let Some(limit) = self.config.rust_annotate_moves_size_limit {
+            rustflags.arg(&format!("-Zannotate-moves={}", limit));
+        } else {
+            rustflags.arg("-Zannotate-moves");
+        }
+
         // FIXME: the following components don't build with `-Zrandomize-layout` yet:
         // - rust-analyzer, due to the rowan crate
         // so we exclude an entire category of steps here due to lack of fine-grained control over

src/bootstrap/src/core/config/config.rs

@@ -217,6 +217,7 @@ pub struct Config {
     pub rust_randomize_layout: bool,
     pub rust_remap_debuginfo: bool,
     pub rust_new_symbol_mangling: Option<bool>,
+    pub rust_annotate_moves_size_limit: Option<u64>,
     pub rust_profile_use: Option<String>,
     pub rust_profile_generate: Option<String>,
     pub rust_lto: RustcLto,
@@ -559,6 +560,7 @@ impl Config {
             control_flow_guard: rust_control_flow_guard,
             ehcont_guard: rust_ehcont_guard,
             new_symbol_mangling: rust_new_symbol_mangling,
+            annotate_moves_size_limit: rust_annotate_moves_size_limit,
             profile_generate: rust_profile_generate,
             profile_use: rust_profile_use,
             download_rustc: rust_download_rustc,
@@ -1419,6 +1421,7 @@ impl Config {
                 .map(|value| RustcLto::from_str(value).unwrap())
                 .unwrap_or_default(),
             rust_new_symbol_mangling,
+            rust_annotate_moves_size_limit,
             rust_optimize: rust_optimize.unwrap_or(RustOptimize::Bool(true)),
             rust_optimize_tests: rust_optimize_tests.unwrap_or(true),
             rust_overflow_checks: rust_overflow_checks.unwrap_or(rust_debug == Some(true)),

src/bootstrap/src/core/config/toml/rust.rs

@@ -60,6 +60,7 @@ define_config! {
         control_flow_guard: Option<bool> = "control-flow-guard",
         ehcont_guard: Option<bool> = "ehcont-guard",
         new_symbol_mangling: Option<bool> = "new-symbol-mangling",
+        annotate_moves_size_limit: Option<u64> = "annotate-moves-size-limit",
         profile_generate: Option<String> = "profile-generate",
         profile_use: Option<String> = "profile-use",
         // ignored; this is set from an env var set by bootstrap.py
@@ -364,6 +365,7 @@ pub fn check_incompatible_options_for_ci_rustc(
         control_flow_guard: _,
         ehcont_guard: _,
         new_symbol_mangling: _,
+        annotate_moves_size_limit: _,
         profile_generate: _,
         profile_use: _,
         download_rustc: _,