Let ZJIT and YJIT disable each other

Merged: https://github.com/ruby/ruby/pull/13131

configure.ac

@@ -3859,40 +3859,40 @@ AC_SUBST(INSTALL_STATIC_LIBRARY)
 [begin]_group "JIT section" && {
 AC_CHECK_PROG(RUSTC, [rustc], [rustc], [no]) dnl no ac_tool_prefix
 
-dnl check if rustc is recent enough to build YJIT (rustc >= 1.58.0)
+dnl check if rustc is recent enough to build YJIT/ZJIT (rustc >= 1.58.0)
-YJIT_RUSTC_OK=no
+JIT_RUSTC_OK=no
 AS_IF([test "$RUSTC" != "no"],
-    AC_MSG_CHECKING([whether ${RUSTC} works for YJIT])
+    AC_MSG_CHECKING([whether ${RUSTC} works for YJIT/ZJIT])
-    YJIT_TARGET_ARCH=
+    JIT_TARGET_ARCH=
     AS_CASE(["$target_cpu"],
-        [arm64|aarch64], [YJIT_TARGET_ARCH=aarch64],
+        [arm64|aarch64], [JIT_TARGET_ARCH=aarch64],
-        [x86_64], [YJIT_TARGET_ARCH=x86_64],
+        [x86_64], [JIT_TARGET_ARCH=x86_64],
     )
     dnl Fails in case rustc target doesn't match ruby target.
     dnl Can happen on Rosetta, for example.
-    AS_IF([echo "#[cfg(target_arch = \"$YJIT_TARGET_ARCH\")] fn main() { let x = 1; format!(\"{x}\"); }" |
+    AS_IF([echo "#[cfg(target_arch = \"$JIT_TARGET_ARCH\")] fn main() { let x = 1; format!(\"{x}\"); }" |
             $RUSTC - --emit asm=/dev/null 2>/dev/null],
-        [YJIT_RUSTC_OK=yes]
+        [JIT_RUSTC_OK=yes]
     )
-    AC_MSG_RESULT($YJIT_RUSTC_OK)
+    AC_MSG_RESULT($JIT_RUSTC_OK)
 )
 
-dnl check if we can build YJIT on this target platform
+dnl check if we can build YJIT/ZJIT on this target platform
 dnl we can't easily cross-compile with rustc so we don't support that
-YJIT_TARGET_OK=no
+JIT_TARGET_OK=no
 AS_IF([test "$cross_compiling" = no],
     AS_CASE(["$target_cpu-$target_os"],
         [*android*], [
-            YJIT_TARGET_OK=no
+            JIT_TARGET_OK=no
         ],
         [arm64-darwin*|aarch64-darwin*|x86_64-darwin*], [
-            YJIT_TARGET_OK=yes
+            JIT_TARGET_OK=yes
         ],
         [arm64-*linux*|aarch64-*linux*|x86_64-*linux*], [
-            YJIT_TARGET_OK=yes
+            JIT_TARGET_OK=yes
         ],
         [arm64-*bsd*|aarch64-*bsd*|x86_64-*bsd*], [
-            YJIT_TARGET_OK=yes
+            JIT_TARGET_OK=yes
         ]
     )
 )
@@ -3902,8 +3902,8 @@ AC_ARG_ENABLE(yjit,
     AS_HELP_STRING([--enable-yjit],
     [enable in-process JIT compiler that requires Rust build tools. enabled by default on supported platforms if rustc 1.58.0+ is available]),
     [YJIT_SUPPORT=$enableval],
-    [AS_CASE(["$YJIT_TARGET_OK:$YJIT_RUSTC_OK"],
+    [AS_CASE(["$JIT_TARGET_OK:$JIT_RUSTC_OK:$ZJIT_SUPPORT"],
-        [yes:yes], [
+        [yes:yes:no], [
             YJIT_SUPPORT=yes
         ],
         [YJIT_SUPPORT=no]
@@ -3915,8 +3915,8 @@ AC_ARG_ENABLE(zjit,
     AS_HELP_STRING([--enable-zjit],
     [enable in-process JIT compiler that requires Rust build tools. enabled by default on supported platforms if rustc 1.58.0+ is available]),
     [ZJIT_SUPPORT=$enableval],
-    [AS_CASE(["$YJIT_TARGET_OK:$YJIT_RUSTC_OK"],
+    [AS_CASE(["$JIT_TARGET_OK:$JIT_RUSTC_OK:$YJIT_SUPPORT"],
-        [yes:yes], [
+        [yes:yes:no], [
             ZJIT_SUPPORT=yes
         ],
         [ZJIT_SUPPORT=no]
@@ -3931,6 +3931,9 @@ AS_CASE(["${YJIT_SUPPORT}"],
     AS_IF([test x"$RUSTC" = "xno"],
         AC_MSG_ERROR([rustc is required. Installation instructions available at https://www.rust-lang.org/tools/install])
     )
+    AS_IF([test x"$ZJIT_SUPPORT" != "xno"],
+        AC_MSG_ERROR([YJIT cannot be enabled when ZJIT is enabled])
+    )
 
     AS_CASE(["${YJIT_SUPPORT}"],
     [yes], [
@@ -3979,6 +3982,9 @@ AS_CASE(["${ZJIT_SUPPORT}"],
     AS_IF([test x"$RUSTC" = "xno"],
         AC_MSG_ERROR([rustc is required. Installation instructions available at https://www.rust-lang.org/tools/install])
     )
+    AS_IF([test x"$YJIT_SUPPORT" != "xno"],
+        AC_MSG_ERROR([ZJIT cannot be enabled when YJIT is enabled])
+    )
 
     AS_CASE(["${ZJIT_SUPPORT}"],
     [yes], [