objc4-680.tar.gz

[apple/objc4.git] / runtime / Messengers.subproj / objc-msg-arm64.s

diff --git a/runtime/Messengers.subproj/objc-msg-arm64.s b/runtime/Messengers.subproj/objc-msg-arm64.s
index 3017bb24a16713a4d95690c471016e2e26a59c74..d2391e2fb924816837172652e5800fbc2e0eada6 100755 (executable)
--- a/runtime/Messengers.subproj/objc-msg-arm64.s
+++ b/runtime/Messengers.subproj/objc-msg-arm64.s
@@ -31,11 +31,14 @@
 #include <arm/arch.h>
 
 
+.data
+
 // _objc_entryPoints and _objc_exitPoints are used by method dispatch
 // caching code to figure out whether any threads are actively 
 // in the cache for dispatching.  The labels surround the asm code
 // that do cache lookups.  The tables are zero-terminated.
-.data
+
+.align 4
 .private_extern _objc_entryPoints
 _objc_entryPoints:
        .quad   _cache_getImp
@@ -44,7 +47,6 @@ _objc_entryPoints:
        .quad   _objc_msgSendSuper2
        .quad   0
 
-.data
 .private_extern _objc_exitPoints
 _objc_exitPoints:
        .quad   LExit_cache_getImp
@@ -191,6 +193,14 @@ LExit$0:
 .endif
 .endmacro
 
+.macro JumpMiss
+.if $0 == NORMAL
+       b       __objc_msgSend_uncached_impcache
+.else
+       b       LGetImpMiss
+.endif
+.endmacro
+
 .macro CacheLookup
        // x1 = SEL, x9 = isa
        ldp     x10, x11, [x9, #CACHE]  // x10 = buckets, x11 = occupied|mask
@@ -212,7 +222,8 @@ LExit$0:
 3:     // wrap: x12 = first bucket, w11 = mask
        add     x12, x12, w11, UXTW #4  // x12 = buckets+(mask<<4)
 
-       // clone scanning loop to crash instead of hang when cache is corrupt
+       // Clone scanning loop to miss instead of hang when cache is corrupt.
+       // The slow path may detect any corruption and halt later.
 
        ldp     x16, x17, [x12]         // {x16, x17} = *bucket
 1:     cmp     x16, x1                 // if (bucket->sel != _cmd)
@@ -226,18 +237,9 @@ LExit$0:
        ldp     x16, x17, [x12, #-16]!  // {x16, x17} = *--bucket
        b       1b                      // loop
 
-3:     // double wrap - busted
-                                       // x0 = receiver
-                                       // x1 = SEL
-       mov     x2, x9                  // x2 = isa
-
-.if $0 == GETIMP
-       mov     x0, #0
-       b       _cache_getImp_corrupt_cache_error
-.else
-       b       _objc_msgSend_corrupt_cache_error
-.endif
-
+3:     // double wrap
+       JumpMiss $0
+       
 .endmacro