[PATCH V2] PowerPC: fix for gdb.base/eh_return.exp

[Carl Love <cel@us.ibm.com>]

Will, Pedro, Kevin, GDB maintainers:

Sorry, resend, the first attempt was missing the mailing list.

I have updated the patch per the comments from Will.  The new version
of the patch uses a PowerPC specific gcc option to suppress the
generation of the Traceback Table information.  The Traceback
information is contained in the .long statements following the last
instruction in the function.  Now the existing test to locate the last
instruction in the function works without any changes.

Note, the use of the gcc mtraceback option is not valid on other
architectures.

I have tested the patch on Power 10 and Intel.

Please let me know if this patch is acceptable.  Thanks for the input
and help with the patch.

                          Carl Love
-----------------------------------------------------------------

PowerPC: fix for gdb.base/eh_return.exp

Disable the Traceback Table generation on PowerPC.  The Traceback Table
consists of multiple .long statement following the final instruction in
the function.  Generation of the .long statements needs to be disabled with
the PowerPC specific gcc compiler option -mtraceback=no so the test will
correctly locate the address of the bclr instruction before the statement
"End of assembler dump."
---
 gdb/testsuite/gdb.base/eh_return.exp | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/gdb/testsuite/gdb.base/eh_return.exp b/gdb/testsuite/gdb.base/eh_return.exp
index df55dbc72da..3a49464af63 100644
--- a/gdb/testsuite/gdb.base/eh_return.exp
+++ b/gdb/testsuite/gdb.base/eh_return.exp
@@ -18,8 +18,30 @@
 
 standard_testfile
 
+if {[istarget "powerpc*"]} then {
+    # PowerPC generates a Traceback Table following each function by default.
+    # The .long statements following the function contain the Traceback Table
+    # information.  For example:
+    #   Dump of assembler code for function eh2:
+    #   0x00000000100009e0 <+0>:     lis     r2,4098
+    #   ...
+    #   0x0000000010000b04 <+292>:   add     r1,r1,r10
+    #   0x0000000010000b08 <+296>:   blr
+    #   0x0000000010000b0c <+300>:   .long 0x0
+    #   0x0000000010000b10 <+304>:   .long 0x1000000
+    #   0x0000000010000b14 <+308>:   .long 0x1000180
+    #   End of assembler dump.
+    #
+    # Disable the Traceback Table generation, using the PowerPC specific
+    # gcc option, so the test gdb_test_multiple "disassemble eh2" will match
+    # the blr instruction not the .long statement.
+    set compile_flags {debug nopie additional_flags=-mtraceback=no}
+} else {
+    set compile_flags {debug nopie}
+}
+
 if {[prepare_for_testing "failed to prepare" $testfile $srcfile \
-	 {debug nopie}]} {
+	 $compile_flags]} {
     return -1
 }
 
-- 
2.31.1