YJIT: Support Rust 1.58.1 for --yjit-stats on Arm (#6410)

* YJIT: Test Rust 1.58.1 as well on Cirrus

* YJIT: Avoid using a Rust 1.60.0 feature

* YJIT: Use autoconf to detect support

* YJIT: We actually need to run it

for checking it properly

* YJIT: Try cfg!(target_feature = "lse")

* Revert "YJIT: Try cfg!(target_feature = "lse")"

This reverts commit 4e2a9ca9a9.

* YJIT: Add --features stats only when it works

* Update configure.ac

Co-authored-by: Maxime Chevalier-Boisvert <maximechevalierb@gmail.com>

.cirrus.yml

@@ -90,6 +90,7 @@ yjit_task:
     matrix:
       - CC: clang-12
         configure: --enable-yjit=dev
+        rustup_init: --default-toolchain=1.58.1
       - CC: gcc-11
         configure: --enable-yjit
   id_script: id
@@ -107,7 +108,7 @@ yjit_task:
   install_rust_script:
     - sudo apt-get update -y
     - sudo apt-get install -y curl
-    - "curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y"
+    - "curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y $rustup_init"
   autogen_script: ./autogen.sh
   configure_script: >-
     source $HOME/.cargo/env && ./configure -C

configure.ac

@@ -3748,23 +3748,44 @@ AS_CASE(["${YJIT_SUPPORT}"],
     ],
     [dev], [
 	rb_rust_target_subdir=debug
-	CARGO_BUILD_ARGS='--features stats,disasm,asm_comments'
+        CARGO_BUILD_ARGS='--features disasm,asm_comments'
 	AC_DEFINE(RUBY_DEBUG, 1)
     ],
     [dev_nodebug], [
 	rb_rust_target_subdir=dev_nodebug
-	CARGO_BUILD_ARGS='--profile dev_nodebug --features stats,disasm,asm_comments'
+        CARGO_BUILD_ARGS='--profile dev_nodebug --features disasm,asm_comments'
     ],
     [stats], [
 	rb_rust_target_subdir=stats
-	CARGO_BUILD_ARGS='--profile stats --features stats'
+        CARGO_BUILD_ARGS='--profile stats'
     ])
 
     AS_IF([test -n "${CARGO_BUILD_ARGS}"], [
         AC_CHECK_TOOL(CARGO, [cargo], [no])
         AS_IF([test x"$CARGO" = "xno"],
             AC_MSG_ERROR([cargo is required. Installation instructions available at https://www.rust-lang.org/tools/install])
-             ]))
+        ])
+
+        # Insn::IncrCounter uses ldaddal, which works only on ARMv8.1+.
+        AC_CACHE_CHECK(yjit stats are broken, rb_cv_broken_yjit_stats, [
+            AC_RUN_IFELSE(
+                [AC_LANG_PROGRAM([[]], [[
+                    @%:@ifdef __aarch64__
+                        asm volatile(".arch armv8-a+lse\n"
+                                     "ldaddal xzr, xzr, @<:@sp@:>@");
+                    @%:@endif
+                ]])],
+                [rb_cv_broken_yjit_stats=no],
+                [rb_cv_broken_yjit_stats=yes],
+                [rb_cv_broken_yjit_stats=yes]
+            )
+        ])
+        # This won't enable stats in release builds because we don't use cargo
+        # for release builds, use rustc directly
+        AS_IF([test "$rb_cv_broken_yjit_stats" = no], [
+            CARGO_BUILD_ARGS="${CARGO_BUILD_ARGS} --features stats"
+        ])
+    )
 
     YJIT_LIBS="yjit/target/${rb_rust_target_subdir}/libyjit.a"
     AS_CASE(["$target_os"],[openbsd*],[

yjit/src/options.rs

@@ -151,19 +151,7 @@ pub fn parse_option(str_ptr: *const std::os::raw::c_char) -> Option<()> {
 
         ("greedy-versioning", "") => unsafe { OPTIONS.greedy_versioning = true },
         ("no-type-prop", "") => unsafe { OPTIONS.no_type_prop = true },
-
-        ("stats", "") => {
-            // Insn::IncrCounter uses ldaddal, which works only on ARMv8.1+.
-            #[cfg(feature = "stats")]
-            #[cfg(target_arch = "aarch64")]
-            if !std::arch::is_aarch64_feature_detected!("lse") {
-                eprintln!("Your processor does not support --yjit-stats. Aborting.");
-                std::process::exit(1);
-            }
-
-            unsafe { OPTIONS.gen_stats = true }
-        },
-
+        ("stats", "") => unsafe { OPTIONS.gen_stats = true },
         ("trace-exits", "") => unsafe { OPTIONS.gen_trace_exits = true; OPTIONS.gen_stats = true },
         ("dump-insns", "") => unsafe { OPTIONS.dump_insns = true },
         ("verify-ctx", "") => unsafe { OPTIONS.verify_ctx = true },