[ppc64] Fix for function descriptors

Marin Cermak has found various testcases (or one of them) of GDB FAIL on
ppc64.

https://sourceware.org/bugzilla/show_bug.cgi?id=20328

.o contained only the function descriptor address.

The DWARF as produced by Tcl Dwarf::assemble:
 <1><27>: Abbrev Number: 4 (DW_TAG_subprogram)
    <28>   DW_AT_name        : main
    <2d>   DW_AT_external    : 1
    <2e>   DW_AT_low_pc      : 0x1001ff98
    <36>   DW_AT_high_pc     : 0x1002ff98
 <2><3e>: Abbrev Number: 5 (DW_TAG_lexical_block)

Runtime info:
$2 = {<text variable, no debug info>} 0x10000674 <.main>
$3 = {void ()} 0x1001ff98 <main>

On Tue, 12 Jul 2016 15:22:49 +0200, Ulrich Weigand wrote:
Well, most of the gdb.dwarf2 test cases simply use explicitly placed labels
for the DW_AT_low_pc / DW_AT_high_pc attributes.

See e.g. dw2-unresolved-main.c:

asm (".globl cu_text_start");
asm ("cu_text_start:");

On Wed, 13 Jul 2016 10:54:00 +0200, Jan Kratochvil wrote:
Now I see I should not do that because:

lib/dwarf.exp:
proc function_range { func src } {

So I am providing this patch.

gdb/testsuite/ChangeLog
2016-07-13  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.dwarf2/atomic-type.exp: Use function_range for low_pc and high_pc.
	* gdb.dwarf2/atomic.c (f): Rename f_end_lbl to f_label.
	* gdb.dwarf2/dw2-bad-mips-linkage-name.c (f): Rename f_end_lbl to
	f_label.
	(g): Rename g_end_lbl to g_label.
	* gdb.dwarf2/dw2-bad-mips-linkage-name.exp: Use function_range for
	low_pc and high_pc.
	* gdb.dwarf2/dw2-lexical-block-bare.exp: Likewise.

1 files changed, 10 insertions, 4 deletions

diff --git a/gdb/testsuite/gdb.dwarf2/dw2-lexical-block-bare.exp b/gdb/testsuite/gdb.dwarf2/dw2-lexical-block-bare.exp
index 3f9411e..d09f56b 100644
--- a/gdb/testsuite/gdb.dwarf2/dw2-lexical-block-bare.exp
+++ b/gdb/testsuite/gdb.dwarf2/dw2-lexical-block-bare.exp
@@ -24,10 +24,16 @@ standard_testfile .S main.c
 # Make some DWARF for the test.
 set asm_file [standard_output_file $srcfile]
 Dwarf::assemble $asm_file {
+    global srcdir subdir srcfile2
+
+    set main_result [function_range main ${srcdir}/${subdir}/${srcfile2}]
+    set main_start [lindex $main_result 0]
+    set main_length [lindex $main_result 1]
+
     cu {} {
 	compile_unit {
-	    {low_pc [gdb_target_symbol main] DW_FORM_addr}
-	    {high_pc [gdb_target_symbol main]+0x10000 DW_FORM_addr}
+	    {low_pc $main_start addr}
+	    {high_pc "$main_start + $main_length" addr}
 	} {
 	    declare_labels integer_label
 
@@ -40,8 +46,8 @@ Dwarf::assemble $asm_file {
 	    DW_TAG_subprogram {
 		{name main}
 		{DW_AT_external 1 flag}
-		{low_pc [gdb_target_symbol main] DW_FORM_addr}
-		{high_pc [gdb_target_symbol main]+0x10000 DW_FORM_addr}
+		{low_pc $main_start addr}
+		{high_pc "$main_start + $main_length" addr}
 	    } {
 		DW_TAG_lexical_block {
 		} {