[PATCH 2/4] python support for fetching separate debug files: have_debug_info

[Doug Evans]

This patch provides an API call to determine whether debug information
is present.  It's based on the same test that gdb internally uses
to decide whether to look for separate debug files.

2014-11-20  Doug Evans  <dje@google.com>

	* NEWS: Mention gdb.Objfile.have_debug_info.
	* python/py-objfile.c (objfpy_get_have_debug_info): New function.
	(objfile_getset): Add "have_debug_info".

	doc/
	* python.texi (Objfiles In Python): Document Objfile.have_debug_info.

	testsuite/
	* gdb.python/py-objfile.exp: Add tests for objfile.have_debug_info.

diff --git a/gdb/NEWS b/gdb/NEWS
index eecc7da..3a36fa8 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -13,6 +13,8 @@
      which is the gdb.Progspace object of the containing program space.
   ** gdb.Objfile objects have a new attribute "build_id",
      which is the build ID generated when the file was built.
+  ** gdb.Objfile objects have a new attribute "have_debug_info", which is
+     a boolean indicating if debug information for the objfile is present.
   ** A new event "gdb.clear_objfiles" has been added, triggered when
      selecting a new file to debug.
   ** You can now add attributes to gdb.Objfile and gdb.Progspace objects.
diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index a47a259..1c9dbb87 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -3457,6 +3457,15 @@ command-line option in @ref{Options, , Command Line Options, ld.info,
 The GNU Linker}.
 @end defvar
 
+@defvar Objfile.have_debug_info
+A boolean indicating if debug information for the objfile is present.
+Note that a program compiled without @samp{-g} may still have some debug
+information, e.g., from the @code{C} runtime.  Thus a value of @code{True}
+for this attribute does not mean that debug information is present for
+every source file in the program.  It only means that debug information
+is present for at least one source file.
+@end defvar
+
 @defvar Objfile.progspace
 The containing program space of the objfile as a @code{gdb.Progspace}
 object.  @xref{Progspaces In Python}.
diff --git a/gdb/python/py-objfile.c b/gdb/python/py-objfile.c
index 05a7c21..5d0933f 100644
--- a/gdb/python/py-objfile.c
+++ b/gdb/python/py-objfile.c
@@ -112,6 +112,32 @@ objfpy_get_build_id (PyObject *self, void *closure)
   Py_RETURN_NONE;
 }
 
+/* An Objfile method which returns whether there debug information
+   has been stripped.  */
+
+static PyObject *
+objfpy_get_have_debug_info (PyObject *self, void *closure)
+{
+  objfile_object *obj = (objfile_object *) self;
+  struct objfile *objfile = obj->objfile;
+
+  if (objfile != NULL)
+    {
+      /* This uses the same test that the file readers use, e.g.,
+	 elf_symfile_read, because its main purpose is to decide whether
+	 separate debug info files should be fetched.
+	 See elf_symfile_read.  */
+      if (!objfile_has_partial_symbols (objfile)
+	  && !objfile_has_full_symbols (objfile)
+	  && objfile->separate_debug_objfile == NULL
+	  && objfile->separate_debug_objfile_backlink == NULL)
+	Py_RETURN_FALSE;
+      Py_RETURN_TRUE;
+    }
+
+  Py_RETURN_FALSE;
+}
+
 /* An Objfile method which returns the objfile's progspace, or None.  */
 
 static PyObject *
@@ -412,6 +438,8 @@ static PyGetSetDef objfile_getset[] =
     "The objfile's filename, or None.", NULL },
   { "build_id", objfpy_get_build_id, NULL,
     "The objfile's build id, or None.", NULL },
+  { "have_debug_info", objfpy_get_have_debug_info, NULL,
+    "True if there is debug information for the objfile.", NULL },
   { "progspace", objfpy_get_progspace, NULL,
     "The objfile's progspace, or None.", NULL },
   { "pretty_printers", objfpy_get_printers, objfpy_set_printers,
diff --git a/gdb/testsuite/gdb.python/py-objfile.exp b/gdb/testsuite/gdb.python/py-objfile.exp
index 74384ed..f09c64c 100644
--- a/gdb/testsuite/gdb.python/py-objfile.exp
+++ b/gdb/testsuite/gdb.python/py-objfile.exp
@@ -49,6 +49,9 @@ if [string compare $binfile_build_id ""] {
     unsupported "build-id is not supported by the compiler"
 }
 
+gdb_test "python print (objfile.have_debug_info)" "True" \
+    "Get objfile have_debug_info"
+
 gdb_test "python print (objfile.progspace)" "<gdb\.Progspace object at .*>" \
   "Get objfile program space"
 gdb_test "python print (objfile.is_valid())" "True" \
@@ -61,3 +64,20 @@ gdb_py_test_silent_cmd "python objfile.random_attribute = 42" \
     "Set random attribute in objfile" 1
 gdb_test "python print (objfile.random_attribute)" "42" \
     "Verify set of random attribute in objfile"
+
+# Now build another copy of the testcase, this time without debug info.
+
+if { [prepare_for_testing ${testfile}.exp ${testfile}2 ${srcfile} {nodebug ldflags=-Wl,--strip-debug}] } {
+    return -1
+}
+
+if ![runto_main] {
+    fail "Can't run to main"
+    return 0
+}
+
+gdb_py_test_silent_cmd "python objfile = gdb.objfiles()\[0\]" \
+    "Get no-debug objfile file" 1
+
+gdb_test "python print (objfile.have_debug_info)" "False" \
+    "Get objfile have_debug_info"