ia64 ABI breaker:

Don't force 16-byte alignment at run-time. Do it at compile-time.
This saves us the pointer fiddling by the setjmp functions and
reduces complexity. While here, increase the jmp_buf by 16 bytes
to an even 512 bytes. Coincidentally, due to the way alignment
was handled prior to this change, the jmp_buf has not changed in
size, but only in how the space is used. Prior to this change
the 16 bytes were reserved for enforcing alignment; now they are
reserved by us for future extensions.
Therefore, this ABI breaker is relatively save: the failure is
always an alignment trap.

3 files changed, 6 insertions, 38 deletions

diff --git a/lib/libc/ia64/gen/_setjmp.S b/lib/libc/ia64/gen/_setjmp.S
index e4e90b2..1357cfa 100644
--- a/lib/libc/ia64/gen/_setjmp.S
+++ b/lib/libc/ia64/gen/_setjmp.S
@@ -69,13 +69,6 @@
 //
 
 ENTRY(_setjmp, 1)
-    //
-    //  Make sure buffer is aligned at 16byte boundary
-    //
-    add     r10 = -0x10,r0  ;;  // mask the lower 4 bits
-    and     r32 = r32, r10;; 
-    add     r32 = 0x10, r32;;   // move to next 16 byte boundary
-
     add     r10 = J_PREDS, r32  // skip Unats & pfs save area
     add     r11 = J_BSP, r32
     //
@@ -200,13 +193,6 @@ END(_setjmp)
 	WEAK_ALIAS(_longjmp,___longjmp)
 ENTRY(___longjmp, 2)
     //
-    //  Make sure buffer is aligned at 16byte boundary
-    //
-    add     r10 = -0x10,r0  ;;  // mask the lower 4 bits
-    and     r32 = r32, r10;; 
-    add     r32 = 0x10, r32;;   // move to next 16 byte boundary
-
-    //
     // caching the return value as we do invala in the end
     //
     mov     r8 = r33            // return value
diff --git a/lib/libc/ia64/gen/setjmp.S b/lib/libc/ia64/gen/setjmp.S
index 0ba630b..817e333 100644
--- a/lib/libc/ia64/gen/setjmp.S
+++ b/lib/libc/ia64/gen/setjmp.S
@@ -46,14 +46,10 @@
 ENTRY(setjmp, 1)
 	alloc	loc0=ar.pfs,1,2,3,0
 	mov	loc1=rp
-	//
-	// Compensate for the pointer twiddling that setjmp does.
-	//
-	dep	r14=r0,r32,0,4
-	;; 
+	;;
 	mov	out0=1				// how = SIG_BLOCK
 	mov	out1=0				// set = NULL
-	add	out2=J_SIG0+0x10,r14		// oset = &jb[J_SIG0]
+	add	out2=J_SIG0,in0			// oset = &jb[J_SIG0]
 	br.call.sptk.few rp=__sys_sigprocmask
 	;;
 	mov	rp=loc1
@@ -69,13 +65,9 @@ END(setjmp)
 ENTRY(__longjmp, 2)
 	alloc	loc0=ar.pfs,2,2,3,0
 	mov	loc1=rp
-	//
-	// Compensate for the pointer twiddling that setjmp does.
-	//
-	dep	r14=r0,r32,0,4
 	;; 
 	mov	out0=3				// how = SIG_SETMASK
-	add	out1=J_SIG0+0x10,r14		// set = &jb[J_SIG0]
+	add	out1=J_SIG0,in0			// set = &jb[J_SIG0]
 	mov	out2=0				// oset = NULL
 	br.call.sptk.few rp=__sys_sigprocmask
 	;;
diff --git a/lib/libc/ia64/gen/sigsetjmp.S b/lib/libc/ia64/gen/sigsetjmp.S
index e3a9768..37e6f95 100644
--- a/lib/libc/ia64/gen/sigsetjmp.S
+++ b/lib/libc/ia64/gen/sigsetjmp.S
@@ -45,27 +45,17 @@
  */
 
 ENTRY(sigsetjmp, 2)
-	//
-	// Compensate for the pointer twiddling that setjmp does.
-	//
-	dep	r14=r0,r32,0,4
-	;; 
-	add	r14=J_SIGMASK+0x10,r14		// place to save mask
+	add	r14=J_SIGMASK,in0		// place to save mask
+	cmp.ne	p6,p7=0,in1			// save signal state?
 	;;
 	st8	[r14]=in1			// save mask value
-	cmp.ne	p6,p7=0,in1			// save signal state?
 (p6)	br.cond.dptk.many setjmp
 (p7)	br.cond.dpnt.many _setjmp		
 END(sigsetjmp)
 
 	WEAK_ALIAS(siglongjmp,__siglongjmp)
 ENTRY(__siglongjmp, 2)
-	//
-	// Compensate for the pointer twiddling that setjmp does.
-	//
-	dep	r14=r0,r32,0,4
-	;; 
-	add	r14=J_SIGMASK+0x10,r14		// address of mask value
+	add	r14=J_SIGMASK,in0		// address of mask value
 	;;
 	ld8	r14=[r14]
 	;;