selftest.h: add class line_table_test

input.c has a fixture class for running each selftest with a fresh
line_table, and logic for looping over various interesting line_table
test cases.

This patch exposes the above in selftest.h so that such
location-handling tests can be written in other files, renaming the
class from temp_line_table to line_table_test.

Also, the patch moves the stored line table ptr from being a member of
the test class to being a global GC-root, to avoid it being collected
if the GC runs during such a test.

gcc/ChangeLog:
	* input.c (saved_line_table): New global.
	(class selftest::temp_line_table): Rename to line_table_test and
	move declaration to selftest.h, and drop field m_old_line_table.
	(selftest::temp_line_table::temp_line_table): Rename ctor to...
	(selftest::line_table_test::line_table_test): ...this.  Add a
	default ctor.  Store current value of line_table within
	saved_line_table.
	(selftest::temp_line_table::~temp_line_table): Rename dtor to...
	(selftest::line_table_test::~line_table_test): ...this, and
	restore line_table from the saved_line_table, rather than
	m_old_line_table.
	(selftest::test_accessing_ordinary_linemaps): Update for above
	renaming.
	(selftest::test_lexer): Likewise.
	(struct selftest::lexer_test): Likewise.
	(selftest::lexer_test::lexer_test): Likewise.
	(selftest::input_c_tests): Move the looping over test cases from
	here into...
	(selftest::for_each_line_table_case): New function.
	* input.h (saved_line_table): New decl.
	* selftest.h (struct selftest::line_table_case): New forward decl.
	(class selftest::line_table_test): New class, moved here from
	selftest::temp_line_table in input.c, and renamed.
	(selftest::for_each_line_table_case): New decl.

From-SVN: r239580

1 files changed, 42 insertions, 0 deletions

diff --git a/gcc/selftest.h b/gcc/selftest.h
index 72de61f..58a40f6 100644
--- a/gcc/selftest.h
+++ b/gcc/selftest.h
@@ -85,6 +85,48 @@ class temp_source_file
   char *m_filename;
 };
 
+/* Various selftests involving location-handling require constructing a
+   line table and one or more line maps within it.
+
+   For maximum test coverage we want to run these tests with a variety
+   of situations:
+   - line_table->default_range_bits: some frontends use a non-zero value
+   and others use zero
+   - the fallback modes within line-map.c: there are various threshold
+   values for source_location/location_t beyond line-map.c changes
+   behavior (disabling of the range-packing optimization, disabling
+   of column-tracking).  We can exercise these by starting the line_table
+   at interesting values at or near these thresholds.
+
+   The following struct describes a particular case within our test
+   matrix.  */
+
+struct line_table_case;
+
+/* A class for overriding the global "line_table" within a selftest,
+   restoring its value afterwards.  At most one instance of this
+   class can exist at once, due to the need to keep the old value
+   of line_table as a GC root.  */
+
+class line_table_test
+{
+ public:
+  /* Default constructor.  Override "line_table", using sane defaults
+     for the temporary line_table.  */
+  line_table_test ();
+
+  /* Constructor.  Override "line_table", using the case described by C.  */
+  line_table_test (const line_table_case &c);
+
+  /* Destructor.  Restore the saved line_table.  */
+  ~line_table_test ();
+};
+
+/* Run TESTCASE multiple times, once for each case in our test matrix.  */
+
+extern void
+for_each_line_table_case (void (*testcase) (const line_table_case &));
+
 /* Declarations for specific families of tests (by source file), in
    alphabetical order.  */
 extern void bitmap_c_tests ();