[PATCH v3 1/2] gdb/testsuite: Add libc_has_debug_info require helper

[Thiago Jung Bauermann <thiago.bauermann@linaro.org>]

Factor the test for libc debug info out of gdb.base/relativedebug.exp to
a new procedure.

Also, change the "info sharedlibrary" test to explicitly detect when
libc has debug info.
---

As mentioned in the cover letter, the new testcase doesn't use this helper
procedure anymore so this is an optional patch.  I think it's a nice
cleanup, though I didn't find any other testcase that need it so perhaps
the new helper is not as useful as I imagine it to be. I'm fine with not
committing this patch.

Changes in v3:
- Include <stdio.h> in test program to avoid error when using clang
  (suggested by Kevin).

 gdb/testsuite/gdb.base/relativedebug.exp | 13 +-----
 gdb/testsuite/lib/gdb.exp                | 56 ++++++++++++++++++++++++
 2 files changed, 57 insertions(+), 12 deletions(-)

diff --git a/gdb/testsuite/gdb.base/relativedebug.exp b/gdb/testsuite/gdb.base/relativedebug.exp
index bf8d76887122..f882a5cf1676 100644
--- a/gdb/testsuite/gdb.base/relativedebug.exp
+++ b/gdb/testsuite/gdb.base/relativedebug.exp
@@ -13,7 +13,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-require {!target_info exists gdb,nosignals}
+require {!target_info exists gdb,nosignals} libc_has_debug_info
 
 standard_testfile .c
 
@@ -28,17 +28,6 @@ clean_restart ${binfile}
 
 runto_main
 
-set test "info sharedlibrary"
-gdb_test_multiple $test $test {
-    -re ".*\(\\*\)\[^\r\n\]*/libc\.so.*$gdb_prompt $" {
-	# Skip the test below if libc doesn't have debug info.
-	unsupported "libc doesn't have debug info"
-	return -1
-    }
-    -re ".*$gdb_prompt $" {
-    }
-}
-
 # pause () -> SIGALRM -> handler () -> abort ()
 gdb_test "continue" "Program received signal SIGABRT.*"
 
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index cbd37fd30947..1e26937c0dcf 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -3699,6 +3699,62 @@ proc support_displaced_stepping {} {
     return 0
 }
 
+# Return 1 if GDB can find the libc debug info, or 0 and a reason string if it
+# can't.  This procedure is meant to be called by the require procedure.
+gdb_caching_proc libc_has_debug_info {} {
+    global srcdir subdir gdb_prompt inferior_exited_re
+
+    set me "libc_has_debug_info"
+
+    # Compile a test program.
+    set src {
+	#include <stdio.h>
+
+	int main (void) {
+	    printf ("Hello, world!\n");
+	    return 0;
+	}
+    }
+    if {![gdb_simple_compile $me $src executable {debug}]} {
+	return [list 0 "failed to compile test program"]
+    }
+
+    # No error message, compilation succeeded so now run it via gdb.
+
+    gdb_exit
+    gdb_start
+    gdb_reinitialize_dir $srcdir/$subdir
+    gdb_load "$obj"
+    runto_main
+    set test "info sharedlibrary libc.so"
+    gdb_test_multiple $test $test {
+	-re ".*\(\\*\)\[^\r\n\]*/libc\.so.*$gdb_prompt $" {
+	    # Matched the "(*)" in the "Syms Read" columns which means:
+	    # "(*): Shared library is missing debugging information."
+	    verbose -log "$me: libc doesn't have debug info"
+	    set libc_has_debug_info 0
+	    set message "libc doesn't have debug info"
+	}
+	-re ".*Yes\[ \t\]+\[^\r\n\]*/libc\.so.*$gdb_prompt $" {
+	    verbose -log "$me: libc has debug info"
+	    set libc_has_debug_info 1
+	}
+	default {
+	    set libc_has_debug_info 0
+	    set message "libc not found in the inferior"
+	}
+    }
+    gdb_exit
+    remote_file build delete $obj
+
+    verbose "$me: returning $libc_has_debug_info" 2
+    if { $libc_has_debug_info } {
+	return $libc_has_debug_info
+    } else {
+	return [list $libc_has_debug_info $message]
+    }
+}
+
 # Run a test on the target to see if it supports vmx hardware.  Return 1 if so, 
 # 0 if it does not.  Based on 'check_vmx_hw_available' from the GCC testsuite.