Avoid .eh_frame in ARM newlib

[Joseph Myers]

ARM newlib has various strcmp implementations that use .cfi_*
directives to generate unwind information.

The effect of this is that the generated objects contain .eh_frame
sections.  However, ARM uses its own unwind info format, not
.eh_frame, which is generated by ARM-specific directives, not .cfi_*.
The .eh_frame sections are useless, but also not removed by strip and
may be loaded into memory at runtime.

This patch fixes this by using .cfi_sections .debug_frame (as in
glibc) so that the directives generate .debug_frame instead.
.debug_frame is useful for the debugger, can be removed by strip, and
is not loaded into memory at runtime.

OK to commit?

2015-11-11  Joseph Myers  <joseph@codesourcery.com>

	* libc/machine/arm/strcmp-arm-tiny.S: Use .cfi_sections
	.debug_frame.
	* libc/machine/arm/strcmp-armv4.S: Likewise.
	* libc/machine/arm/strcmp-armv4t.S: Likewise.
	* libc/machine/arm/strcmp-armv6.S: Likewise.
	* libc/machine/arm/strcmp-armv6m.S: Likewise.
	* libc/machine/arm/strcmp-armv7.S: Likewise.
	* libc/machine/arm/strcmp-armv7m.S: Likewise.

diff --git a/newlib/libc/machine/arm/strcmp-arm-tiny.S b/newlib/libc/machine/arm/strcmp-arm-tiny.S
index 158133f..6b6bd13 100644
--- a/newlib/libc/machine/arm/strcmp-arm-tiny.S
+++ b/newlib/libc/machine/arm/strcmp-arm-tiny.S
@@ -31,6 +31,7 @@
 
 	.syntax unified
 def_fn strcmp
+	.cfi_sections .debug_frame
 	.cfi_startproc
 1:
 	ldrb	r2, [r0], #1
diff --git a/newlib/libc/machine/arm/strcmp-armv4.S b/newlib/libc/machine/arm/strcmp-armv4.S
index b18c3db..05e3df6 100644
--- a/newlib/libc/machine/arm/strcmp-armv4.S
+++ b/newlib/libc/machine/arm/strcmp-armv4.S
@@ -45,6 +45,7 @@
 
 	.arm
 def_fn strcmp
+	.cfi_sections .debug_frame
 	.cfi_startproc
 	eor	tmp1, src1, src2
 	tst	tmp1, #3
diff --git a/newlib/libc/machine/arm/strcmp-armv4t.S b/newlib/libc/machine/arm/strcmp-armv4t.S
index 2716b87..d01d840 100644
--- a/newlib/libc/machine/arm/strcmp-armv4t.S
+++ b/newlib/libc/machine/arm/strcmp-armv4t.S
@@ -36,6 +36,7 @@
 	.eabi_attribute Tag_also_compatible_with, "\006\013" /* ARMv6-M.  */
 	.eabi_attribute Tag_ARM_ISA_use, 0
 def_fn strcmp
+	.cfi_sections .debug_frame
 	.cfi_startproc
 1:
 	ldrb	r2, [r0]
diff --git a/newlib/libc/machine/arm/strcmp-armv6.S b/newlib/libc/machine/arm/strcmp-armv6.S
index a557fc5..657c1ee 100644
--- a/newlib/libc/machine/arm/strcmp-armv6.S
+++ b/newlib/libc/machine/arm/strcmp-armv6.S
@@ -131,6 +131,7 @@ def_fn	strcmp
 	cmpcs	r2, r3
 	bne	.Lfastpath_exit
 #endif
+	.cfi_sections .debug_frame
 	.cfi_startproc
 	strd	r4, r5, [sp, #-16]!
 	.cfi_def_cfa_offset 16
diff --git a/newlib/libc/machine/arm/strcmp-armv6m.S b/newlib/libc/machine/arm/strcmp-armv6m.S
index 932841d..74f87cb 100644
--- a/newlib/libc/machine/arm/strcmp-armv6m.S
+++ b/newlib/libc/machine/arm/strcmp-armv6m.S
@@ -53,6 +53,7 @@
 
 	.text
 def_fn	strcmp
+	.cfi_sections .debug_frame
 	.cfi_startproc
 	mov	r2, r0
 	push	{r4, r5, r6, lr}
diff --git a/newlib/libc/machine/arm/strcmp-armv7.S b/newlib/libc/machine/arm/strcmp-armv7.S
index e2c47ff..2f93bfb 100644
--- a/newlib/libc/machine/arm/strcmp-armv7.S
+++ b/newlib/libc/machine/arm/strcmp-armv7.S
@@ -136,6 +136,7 @@ def_fn	strcmp
 	cmpcs	r2, r3
 	bne	.Lfastpath_exit
 #endif
+	.cfi_sections .debug_frame
 	.cfi_startproc
 	strd	r4, r5, [sp, #-16]!
 	.cfi_def_cfa_offset 16
diff --git a/newlib/libc/machine/arm/strcmp-armv7m.S b/newlib/libc/machine/arm/strcmp-armv7m.S
index d66d393..7b63049 100644
--- a/newlib/libc/machine/arm/strcmp-armv7m.S
+++ b/newlib/libc/machine/arm/strcmp-armv7m.S
@@ -44,6 +44,7 @@
 	.thumb
 	.syntax unified
 def_fn strcmp
+	.cfi_sections .debug_frame
 	.cfi_startproc
 	eor	tmp1, src1, src2
 	tst	tmp1, #3

-- 
Joseph S. Myers
joseph@codesourcery.com