readelf: objdump: sframe: fix dumping with section name

Fix PR binutils/33186 - No SFrame dump if section name is not .sframe

When the section name is not ".sframe", ensure that readelf and objdump
are able to dump a section of type SHT_GNU_SFRAME and not fail if the
user specifies the new section name.

For objdump, in dump_dwarf_section (), use the match string of ".sframe"
to find the corresponding debug_displays[] item for SFrame section.
Doing this ensures that any call to dump_dwarf_section () with the
section pointing to the SFrame section (with name possibly different
from ".sframe") will successfully dump the SFrame section.

If the SFrame section is named anything but ".sframe", and user does not
specify the name of the SFrame section either, the documented behaviour
is that the default section name is assumed to be ".sframe".  So the
following (albeit counter intuitive) is expected at this time:

$ readelf -S sort | grep sframe
  [NN] .sframe2          GNU_SFRAME       0000000000NNNNNN  0000NNNN

(Note section name .sframe2).

$ objdump --sframe sort

sort:     file format elf64-x86-64

No .sframe section present

(Similarly for readelf as well).

For objdump, set dump_sframe_section_name to ".sframe" if user specifies
no section name.  In the error checking done in dump_sframe_section, add
the case when user specifies a valid section name but one that does not
contain SFrame section data.  For sections generated with Binutils >=
2.45, this can be checked with section type of SHT_GNU_SFRAME.
Previously these sections were SHT_PROGBITS with name ".sframe".

Similar changes in readelf.

Add a test each for objdump and readelf to dump a renamed section.  Use
gas_sframe_check to limit the execution of these tests only when a gas
supporting SFrame format is present.

binutils/
	PR binutils/33186
	* objdump.c (dump_dwarf_section): Set match to ".sframe" which
	corresponds to the name in the debug_displays[] entry for
	SFrame section.
	(dump_sframe_section): Check if the user specified section name
	contains SFrame data.
	(main): Set default section name to ".sframe".
	* readelf.c (display_debug_section): Adjust checks to find the
	debug_diplays[] item for the input arg SFrame section.
	Use id instead of i, as it is more readable.

binutils/testsuite/
	PR binutils/33186
	* binutils-all/x86-64/objdump-sframe-01.d: New test.
	* binutils-all/x86-64/readelf-sframe-01.d: New test.
	* binutils-all/x86-64/sframe-func.s: New test.

binutils/testsuite/binutils-all/x86-64/objdump-sframe-01.d

@@ -0,0 +1,18 @@
+#PROG:objcopy
+#name: objdump dump SFrame section .sframe2
+#source: sframe-func.s
+#as: --gsframe
+#objcopy: --rename-section .sframe=.sframe2
+#objdump: --sframe=.sframe2
+#target: x86_64-*-*
+#xfail: ![gas_sframe_check]
+
+#...
+  Header :
+
+    Version: SFRAME_VERSION_2
+    Flags: SFRAME_F_FDE_FUNC_START_PCREL
+    CFA fixed RA offset: -8
+    Num FDEs: 1
+    Num FREs: 4
+#pass

binutils/testsuite/binutils-all/x86-64/readelf-sframe-01.d

@@ -0,0 +1,18 @@
+#PROG:objcopy
+#name: readelf dump SFrame section .sframe2
+#source: sframe-func.s
+#as: --gsframe
+#objcopy: --rename-section .sframe=.sframe2
+#readelf: --sframe=.sframe2
+#target: x86_64-*-*
+#xfail: ![gas_sframe_check]
+
+#...
+  Header :
+
+    Version: SFRAME_VERSION_2
+    Flags: SFRAME_F_FDE_FUNC_START_PCREL
+    CFA fixed RA offset: -8
+    Num FDEs: 1
+    Num FREs: 4
+#pass

binutils/testsuite/binutils-all/x86-64/sframe-func.s

@@ -0,0 +1,11 @@
+	.cfi_sections .sframe
+	.cfi_startproc
+	.long 8
+	.cfi_def_cfa_offset 16
+	.cfi_offset 6, -16
+	.long 8
+	.cfi_def_cfa_register 6
+	.long 8
+	.cfi_def_cfa 7, 8
+	.long 8
+	.cfi_endproc