[PATCHv2,2/2] gdb/testsuite: fix gdb.debuginfod/fetch_src_and_symbols.exp with Clang

Message ID ddaa73456d3b605d200b0af63a9c21ceca75cefa.1668684812.git.aburgess@redhat.com
State Committed
Commit e86741b65ba9a614054241c0be45efb04484e320
Series Fix gdb.debuginfod/fetch_src_and_symbols.exp with Clang |

Commit Message

Andrew Burgess Nov. 17, 2022, 11:38 a.m. UTC
  The gdb.debuginfod/fetch_src_and_symbols.exp test is showing a single
failure when run with some older versions of Clang, e.g. 9.0.1.

The problem appears to be with Clang's generated line table.  The test
source looks like this:

    asm ("main_label: .globl main_label");
    return 0;

In GDB, when we 'start', we expect to stop at the 'return 0;' line.
This is the behaviour when the compiler is gcc, or later versions of

However, with Clang 9.0.2, I see GDB stop on the 'asm' line.

In this commit I'll fix this issue by placing a breakpoint on the
return line, and then using gdb_continue_to_breakpoint to ensure we
have stopped in the correct place.

Of course, using gdb_continue_to_breakpoint will only work if we are
not already stopped at the breakpoint location, so I've added some
filler work before the 'return 0;' line.  With this done we can use
gdb_continue_to_breakpoint in all cases.

As a result of adding the new filler work, one of the later tests,
that used the 'list' command, no longer see the correct expected
output (the top line of the source file is no longer included in the
output).  I've fixed this by listing a known specific line, the test
is checking that GDB managed to find the source file, it doesn't
matter which source line we list, as long as we can list something.
 gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.c   | 5 ++++-
 gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.exp | 7 ++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)


diff --git a/gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.c b/gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.c
index 412bd53edda..7215e3c6484 100644
--- a/gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.c
+++ b/gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.c
@@ -15,11 +15,14 @@ 
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+volatile int global_var = 0;
 /* Dummy main function.  */
   asm ("main_label: .globl main_label");
-  return 0;
+  ++global_var;
+  return 0;	/* Breakpoint here.  */
diff --git a/gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.exp b/gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.exp
index 8b3c2cf709e..e95526a069f 100644
--- a/gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.exp
+++ b/gdb/testsuite/gdb.debuginfod/fetch_src_and_symbols.exp
@@ -161,6 +161,10 @@  proc_with_prefix no_url { } {
     if ![runto_main] {
 	return -1
+    gdb_breakpoint [gdb_get_line_number "Breakpoint here"]
+    gdb_continue_to_breakpoint "stop at last line of main"
     gdb_test "generate-core-file $::corefile" "Saved corefile $::corefile" \
 	"file [file tail $::corefile] gen"
     file rename -force ${binfile}2 $debugdir
@@ -217,7 +221,8 @@  proc_with_prefix local_url { } {
     gdb_test_no_output "set substitute-path $outputdir /dev/null" \
 	"set substitute-path"
     gdb_test "br main" "Breakpoint 1 at.*file.*"
-    gdb_test "l" ".*This program is distributed in the hope.*"
+    set lineno [gdb_get_line_number "Breakpoint here"]
+    gdb_test "list $lineno" "return 0;\[^\r\n\]+Breakpoint here\\. .*"
     # GDB should now find the executable file.