PowerPC64 power7 strncpy stack handling and cfi

This patch moves the frame setup and teardown to immediately around
the single memset call, as has been done for power8.  I've also
decreased FRAMESIZE to that needed to save the two callee-saved
registers used.  Plus added cfi.

	* sysdeps/powerpc/powerpc64/power7/strncpy.S: Decrease FRAMESIZE.
	Move LR save and frame setup/teardown and LR restore to
	immediately around memset call.  Provide cfi.

Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>

diff --git a/ChangeLog b/ChangeLog
index 5d45da1d8cc0bf931e463d03334dc93ae712604d..444b63981fb47a90d303749334d1fd763621d714 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2017-10-23  Alan Modra  <amodra@gmail.com>
+
+       * sysdeps/powerpc/powerpc64/power7/strncpy.S: Decrease FRAMESIZE.
+       Move LR save and frame setup/teardown and LR restore to
+       immediately around memset call.  Provide cfi.
+
 2017-10-22  H.J. Lu  <hongjiu.lu@intel.com>
 
        * sysdeps/i386/fpu/e_powf.S: Removed.

diff --git a/sysdeps/powerpc/powerpc64/power7/strncpy.S b/sysdeps/powerpc/powerpc64/power7/strncpy.S
index b2833b8a503ddbfd054ed5cfabd51c484d3e380f..0ae65a0fc5a1ceaa665dd58cde3caac4485b7650 100644 (file)
--- a/sysdeps/powerpc/powerpc64/power7/strncpy.S
+++ b/sysdeps/powerpc/powerpc64/power7/strncpy.S
@@ -53,7 +53,7 @@
 # endif
 #endif  /* !USE_AS_STPNCPY  */
 
-#define                FRAMESIZE       (FRAME_MIN_SIZE+32)
+#define                FRAMESIZE       (FRAME_MIN_SIZE+16)
 
 #ifndef MEMSET
 /* For builds with no IFUNC support, local calls should be made to internal
@@ -74,14 +74,13 @@ ENTRY (FUNC_NAME, 4)
 #endif
        CALL_MCOUNT 3
 
-       mflr r0                 /* load link register LR to r0  */
        or r10, r3, r4          /* to verify source and destination  */
        rldicl. r8, r10, 0, 61  /* is double word aligned .. ?  */
 
        std r19, -8(r1)         /* save callers register , r19  */
        std r18, -16(r1)        /* save callers register , r18  */
-       std r0, 16(r1)          /* store the link register  */
-       stdu r1, -FRAMESIZE(r1) /* create the stack frame  */
+       cfi_offset(r19, -8)
+       cfi_offset(r18, -16)
 
        mr r9, r3               /* save r3 into r9 for use  */
        mr r18, r3              /* save r3 for retCode of strncpy  */
@@ -224,6 +223,11 @@ L(zeroFill):
        cmpdi cr7, r8, 0        /* compare if length is zero  */
        beq cr7, L(update3return)
 
+       mflr r0                 /* load link register LR to r0  */
+       std r0, 16(r1)          /* store the link register  */
+       stdu r1, -FRAMESIZE(r1) /* create the stack frame  */
+       cfi_adjust_cfa_offset(FRAMESIZE)
+       cfi_offset(lr, 16)
        mr r3, r19              /* fill buffer with  */
        li r4, 0                /* zero fill buffer  */
        mr r5, r8               /* how many bytes to fill buffer with  */
@@ -231,6 +235,11 @@ L(zeroFill):
 #ifndef MEMSET_is_local
        nop
 #endif
+       ld r0, FRAMESIZE+16(r1) /* read the saved link register  */
+       addi r1, r1, FRAMESIZE  /* restore stack pointer  */
+       cfi_adjust_cfa_offset(-FRAMESIZE)
+       mtlr r0
+       cfi_restore(lr)
 
 L(update3return):
 #ifdef USE_AS_STPNCPY
@@ -241,11 +250,8 @@ L(hop2return):
 #ifndef USE_AS_STPNCPY
        mr r3, r18              /* set return value  */
 #endif
-       addi r1, r1, FRAMESIZE  /* restore stack pointer  */
-       ld r0, 16(r1)           /* read the saved link register  */
        ld r18, -16(r1)         /* restore callers save register, r18  */
        ld r19, -8(r1)          /* restore callers save register, r19  */
-       mtlr r0                 /* branch to link register  */
        blr                     /* return  */
 
        .p2align 4
@@ -279,16 +285,13 @@ L(oneBYone):
 
        .p2align 4
 L(done):
-       addi r1, r1, FRAMESIZE  /* restore stack pointer  */
 #ifdef USE_AS_STPNCPY
        mr r3, r19              /* set the return value  */
 #else
        mr r3, r18              /* set the return value  */
 #endif
-       ld r0, 16(r1)           /* read the saved link register  */
        ld r18, -16(r1)         /* restore callers save register, r18  */
        ld r19, -8(r1)          /* restore callers save register, r19  */
-       mtlr r0                 /* branch to link register  */
        blr                     /* return  */
 
 L(update1):