[PATCH roland/arm-unwind-macros] ARM: Macroize assembly use of EABI unwind directives.

[PATCH roland/arm-unwind-macros] ARM: Macroize assembly use of EABI unwind directives.

[Roland McGrath]

In a configuration that does not use EABI unwind info, using the directives
for it anywhere causes link-time references to magic symbols that such a
configuration's libgcc won't necessarily define.  (I haven't changed the
uses in .../linux/arm/ files because there is no configuration planned
using those files that doesn't use EABI unwind info.)

Tested on armv7l-linux-gnueabihf that compiled code was unchanged by the
patch.


Thanks,
Roland


ports/ChangeLog.arm
2013-04-19  Roland McGrath  <roland@hack.frob.com>

	* sysdeps/arm/sysdep.h
	(eabi_fnstart, eabi_fnend, eabi_save, eabi_cantunwind, eabi_pad):
	New macros.
	* sysdeps/arm/dl-tlsdesc.S: Use them.

--- a/ports/sysdeps/arm/dl-tlsdesc.S
+++ b/ports/sysdeps/arm/dl-tlsdesc.S
@@ -29,13 +29,13 @@
 	.global	_dl_tlsdesc_return
 	.type	_dl_tlsdesc_return,#function
 	cfi_startproc
-	.fnstart
+	eabi_fnstart
 	.align 2
 _dl_tlsdesc_return:
 	sfi_breg r0, \
 	ldr	r0, [\B]
 	BX	(lr)
-	.fnend
+	eabi_fnend
 	cfi_endproc
 	.size	_dl_tlsdesc_return, .-_dl_tlsdesc_return
 
@@ -43,14 +43,14 @@ _dl_tlsdesc_return:
 	.global	_dl_tlsdesc_undefweak
 	.type	_dl_tlsdesc_undefweak,#function
 	cfi_startproc
-	.fnstart
+	eabi_fnstart
 	.align 2
 _dl_tlsdesc_undefweak:
 	GET_TLS (r1)
 	rsb 	r0, r0, #0
 	BX	(lr)
 	cfi_endproc
-	.fnend
+	eabi_fnend
 	.size	_dl_tlsdesc_undefweak, .-_dl_tlsdesc_undefweak
 
 #ifdef SHARED
@@ -80,12 +80,12 @@ _dl_tlsdesc_dynamic(struct tlsdesc *tdp)
 
 */
 	cfi_startproc
-	.fnstart
+	eabi_fnstart
 	.align 2
 _dl_tlsdesc_dynamic:
 	/* Our calling convention is to clobber r0, r1 and the processor
 	   flags.  All others that are modified must be saved */
-	.save	{r2,r3,r4,lr}
+	eabi_save ({r2,r3,r4,lr})
 	push	{r2,r3,r4,lr}
 	cfi_adjust_cfa_offset (16)
 	cfi_rel_offset (r2,0)
@@ -135,7 +135,7 @@ _dl_tlsdesc_dynamic:
 #else
 	pop	{r2,r3,r4, pc}
 #endif
-	.fnend
+	eabi_fnend
 	cfi_endproc
 	.size	_dl_tlsdesc_dynamic, .-_dl_tlsdesc_dynamic
 #endif /* SHARED */
@@ -145,7 +145,7 @@ _dl_tlsdesc_dynamic:
 	.global	_dl_tlsdesc_lazy_resolver
 	.type	_dl_tlsdesc_lazy_resolver,#function
 	cfi_startproc
-	.fnstart
+	eabi_fnstart
 	.align 2
 _dl_tlsdesc_lazy_resolver:
 	/* r0 points at the tlsdesc,
@@ -155,10 +155,10 @@ _dl_tlsdesc_lazy_resolver:
 	  We push the remaining call-clobbered registers here, and also
 	  R1 -- to keep the stack correctly aligned.  */
 	/* Tell the unwinder that r2 has already been pushed.  */
-	.save	{r2}
+	eabi_save ({r2})
 	cfi_adjust_cfa_offset (4)
 	cfi_rel_offset (r2, 0)
-	.save	{r0,r1,r3,ip,lr}
+	eabi_save ({r0,r1,r3,ip,lr})
 	push	{r0, r1, r3, ip, lr}
 	cfi_adjust_cfa_offset (20)
 	cfi_rel_offset (r0, 0)
@@ -180,7 +180,7 @@ _dl_tlsdesc_lazy_resolver:
 	sfi_breg r0, \
 	ldr	r1, [\B, #4]
 	BX	(r1)
-	.fnend
+	eabi_fnend
 	cfi_endproc
 	.size	_dl_tlsdesc_lazy_resolver, .-_dl_tlsdesc_lazy_resolver
 
@@ -190,14 +190,14 @@ _dl_tlsdesc_lazy_resolver:
 	.global	_dl_tlsdesc_resolve_hold
 	.type	_dl_tlsdesc_resolve_hold,#function
 	cfi_startproc
-	.fnstart
+	eabi_fnstart
 	.align 2
 _dl_tlsdesc_resolve_hold:
 	/* Tell the unwinder that r2 has already been pushed.  */
-	.save	{r2}
+	eabi_save ({r2})
 	cfi_adjust_cfa_offset (4)
 	cfi_rel_offset (r2, 0)
-	.save	{r0,r1,r3,ip,lr}
+	eabi_save ({r0,r1,r3,ip,lr})
 	push	{r0, r1, r3, ip, lr}
 	cfi_adjust_cfa_offset (20)
 	cfi_rel_offset (r0, 0)
@@ -220,6 +220,6 @@ _dl_tlsdesc_resolve_hold:
 	sfi_breg r0, \
 	ldr     r1, [\B, #4]
 	BX      (r1)
-	.fnend
+	eabi_fnend
 	cfi_endproc
 	.size	_dl_tlsdesc_resolve_hold, .-_dl_tlsdesc_resolve_hold
--- a/ports/sysdeps/arm/sysdep.h
+++ b/ports/sysdeps/arm/sysdep.h
@@ -257,6 +257,15 @@
 
 # endif
 
+/* These are the directives used for EABI unwind info.
+   Wrap them in macros so another configuration's sysdep.h
+   file can define them away if it doesn't use EABI unwind info.  */
+# define eabi_fnstart		.fnstart
+# define eabi_fnend		.fnend
+# define eabi_save(...)		.save __VA_ARGS__
+# define eabi_cantunwind	.cantunwind
+# define eabi_pad(n)		.pad n
+
 #endif	/* __ASSEMBLER__ */
 
 /* This number is the offset from the pc at the current location.  */

Re: [PATCH roland/arm-unwind-macros] ARM: Macroize assembly use of EABI unwind directives.

[Joseph S. Myers]

On Fri, 19 Apr 2013, Roland McGrath wrote:

> ports/ChangeLog.arm
> 2013-04-19  Roland McGrath  <roland@hack.frob.com>
> 
> 	* sysdeps/arm/sysdep.h
> 	(eabi_fnstart, eabi_fnend, eabi_save, eabi_cantunwind, eabi_pad):
> 	New macros.
> 	* sysdeps/arm/dl-tlsdesc.S: Use them.

OK.

-- 
Joseph S. Myers
joseph@codesourcery.com