i#1551 ARM, i#1569 AArch64: Replace atomic_xchg with atomic_swap.

In arm.asm, atomic_xchg and atomic_swap were defined identically. Review-URL: https://codereview.appspot.com/298390043
DynamoRIO · Jun 10, 2016 · 5a466b1 · 5a466b1
1 parent 4f765b3
commit 5a466b1
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Showing 2 changed files with 10 additions and 26 deletions.
diff --git a/core/arch/aarch64/aarch64.asm b/core/arch/aarch64/aarch64.asm
@@ -222,8 +222,7 @@ cat_no_thread:
         adrp     x26, :got:initstack_mutex
         ldr      x26, [x26, #:got_lo12:initstack_mutex]
 cat_spin:
-        CALLC2(atomic_xchg, x26, #1)
-        /* atomic_xchg */
+        CALLC2(atomic_swap, x26, #1)
         cbz      w0, cat_have_lock
         yield
         b        cat_spin
@@ -269,15 +268,6 @@ GLOBAL_LABEL(atomic_add:)
         cbnz     w3, 1b
         ret
 
-        /* int atomic_xchg(int *adr, int val) */
-        DECLARE_FUNC(atomic_xchg)
-GLOBAL_LABEL(atomic_xchg:)
-1:      ldxr     w2, [x0]
-        stxr     w3, w1, [x0]
-        cbnz     w3, 1b
-        mov      w0, w2
-        ret
-
         DECLARE_FUNC(global_do_syscall_int)
 GLOBAL_LABEL(global_do_syscall_int:)
         /* FIXME i#1569: NYI on AArch64 */
@@ -413,9 +403,14 @@ GLOBAL_LABEL(dr_longjmp:)
         br       x30
         END_FUNC(dr_longjmp)
 
+        /* int atomic_swap(int *adr, int val) */
         DECLARE_FUNC(atomic_swap)
 GLOBAL_LABEL(atomic_swap:)
-        bl       GLOBAL_REF(unexpected_return) /* FIXME i#1569: NYI */
+1:      ldxr     w2, [x0]
+        stxr     w3, w1, [x0]
+        cbnz     w3, 1b
+        mov      w0, w2
+        ret
         END_FUNC(atomic_swap)
 
 #endif /* CLIENT_INTERFACE */

diff --git a/core/arch/arm/arm.asm b/core/arch/arm/arm.asm
@@ -280,14 +280,14 @@ cat_thread_only:
         CALLC0(GLOBAL_REF(dynamo_thread_exit))
 cat_no_thread:
         /* switch to initstack for cleanup of dstack */
-        /* we use r6, r7, and r8 here so that atomic_xchg doesn't clobber them */
+        /* we use r6, r7, and r8 here so that atomic_swap doesn't clobber them */
         mov      REG_R6, #1
         ldr      REG_R8, .Lgot1
         add      REG_R8, REG_R8, pc
         ldr      REG_R7, .Linitstack_mutex
 .LPIC1: ldr      REG_R7, [REG_R7, REG_R8]
 cat_spin:
-        CALLC2(atomic_xchg, REG_R7, REG_R6)
+        CALLC2(atomic_swap, REG_R7, REG_R6)
         cmp      REG_R0, #0
         beq      cat_have_lock
         yield
@@ -355,17 +355,6 @@ GLOBAL_LABEL(atomic_add:)
         bx       lr
         END_FUNC(atomic_add)
 
-/* Pass in the memory address in ARG1 and register w/ value in ARG2. */
-        DECLARE_FUNC(atomic_xchg)
-GLOBAL_LABEL(atomic_xchg:)
-1:      ldrex    REG_R2, [ARG1]
-        strex    REG_R3, ARG2, [ARG1]
-        cmp      REG_R3, #0
-        bne      1b
-        mov      REG_R0, REG_R2
-        bx       lr
-        END_FUNC(atomic_xchg)
-
         DECLARE_FUNC(global_do_syscall_int)
 GLOBAL_LABEL(global_do_syscall_int:)
         /* FIXME i#1551: NYI on ARM */
@@ -493,7 +482,7 @@ GLOBAL_LABEL(dr_longjmp:)
         bx       lr
         END_FUNC(dr_longjmp)
 
-/* uint atomic_swap(uint *addr, uint value)
+/* int atomic_swap(volatile int *addr, int value)
  * return current contents of addr and replace contents with value.
  */
         DECLARE_FUNC(atomic_swap)