[PATCH 08/16] (partially-approved): Introduce selftest::locate_file

[David Malcolm <dmalcolm@redhat.com>]

Jeff:
> I do think we should go ahead and plan for a target subdirectory.  With
> that added, this should be OK once dependencies are in.

Loading RTL dumps from files rather than embedding them as strings
in the source requires a way to locate the relevant files.

This patch adds a selftest::locate_file function for locating such
files, relative to "$(SRCDIR)/gcc/testsuite/selftests".  This is
done via a new argument to -fself-test, which supplies the current
value of "$(SRCDIR)/gcc" to cc1.

I chose "$(SRCDIR)/gcc/testsuite/selftests", so as to be below
gcc/testsuite, but not below any of the existing DejaGnu subdirectories,
to avoid selftest-specific files from being picked up by .exp globbing
patterns.

(Depends on the approved-when-needed
  "[PATCH 2/9] Add selftest::read_file"
    https://gcc.gnu.org/ml/gcc-patches/2016-09/msg00476.html ).

gcc/ChangeLog:
	* Makefile.in (s-selftest) Add $(srcdir) as an argument of
	-fself-test.
	(selftest-gdb): Likewise.
	(selftest-valgrind): Likewise.
	* common.opt (fself-test): Rename to...
	(fself-test=): ...this, documenting the meaning of the argument.
	* selftest-run-tests.c: Include "options.h".
	(selftest::run_tests): Initialize selftest::path_to_src_gcc from
	flag_self_test.
	* selftest.c (selftest::path_to_src_gcc): New global.
	(selftest::locate_file): New function.
	(selftest::test_locate_file): New function.
	(selftest::selftest_c_tests): Call test_locate_file.
	* selftest.h (selftest::locate_file): New decl.
	(selftest::path_to_src_gcc): New decl.

gcc/testsuite/ChangeLog:
	* gcc.dg/cpp/pr71591.c: Add a fake value for the argument of
	-fself-test.
	* selftests/example.txt: New file.
---
 gcc/Makefile.in                     |  7 ++++---
 gcc/common.opt                      |  6 +++---
 gcc/selftest-run-tests.c            |  7 +++++++
 gcc/selftest.c                      | 28 ++++++++++++++++++++++++++++
 gcc/selftest.h                      | 10 ++++++++++
 gcc/testsuite/gcc.dg/cpp/pr71591.c  |  2 +-
 gcc/testsuite/selftests/example.txt |  1 +
 7 files changed, 54 insertions(+), 7 deletions(-)
 create mode 100644 gcc/testsuite/selftests/example.txt

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 15c48bc..4b50f0b 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1883,18 +1883,19 @@ rest.cross: specs
 .PHONY: selftest
 selftest: s-selftest
 s-selftest: $(GCC_PASSES) cc1$(exeext) stmp-int-hdrs
-	$(GCC_FOR_TARGET) -xc -S -c /dev/null -fself-test
+	$(GCC_FOR_TARGET) -xc -S -c /dev/null -fself-test=$(srcdir)
 	$(STAMP) $@
 
 # Convenience method for running selftests under gdb:
 .PHONY: selftest-gdb
 selftest-gdb: $(GCC_PASSES) cc1$(exeext) stmp-int-hdrs
-	$(GCC_FOR_TARGET) -xc -S -c /dev/null -fself-test -wrapper gdb,--args
+	$(GCC_FOR_TARGET) -xc -S -c /dev/null -fself-test=$(srcdir) \
+	  -wrapper gdb,--args
 
 # Convenience method for running selftests under valgrind:
 .PHONY: selftest-valgrind
 selftest-valgrind: $(GCC_PASSES) cc1$(exeext) stmp-int-hdrs
-	$(GCC_FOR_TARGET) -xc -S -c /dev/null -fself-test \
+	$(GCC_FOR_TARGET) -xc -S -c /dev/null -fself-test=$(srcdir) \
 	  -wrapper valgrind,--leak-check=full
 
 # Recompile all the language-independent object files.
diff --git a/gcc/common.opt b/gcc/common.opt
index 3425c19..c3cf4c2 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2106,9 +2106,9 @@ fselective-scheduling2
 Common Report Var(flag_selective_scheduling2) Optimization
 Run selective scheduling after reload.
 
-fself-test
-Common Undocumented Var(flag_self_test)
-Run self-tests.
+fself-test=
+Common Undocumented Joined Var(flag_self_test)
+Run self-tests, using the given path to locate test files.
 
 fsel-sched-pipelining
 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
diff --git a/gcc/selftest-run-tests.c b/gcc/selftest-run-tests.c
index 54a9b0f..ecc3d71 100644
--- a/gcc/selftest-run-tests.c
+++ b/gcc/selftest-run-tests.c
@@ -23,6 +23,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "selftest.h"
 #include "tree.h"
 #include "langhooks.h"
+#include "options.h"
 
 /* This function needed to be split out from selftest.c as it references
    tests from the whole source tree, and so is within
@@ -37,6 +38,12 @@ along with GCC; see the file COPYING3.  If not see
 void
 selftest::run_tests ()
 {
+  /* Makefile.in has -fself-test=$(srcdir), so that flag_self_test
+     contains the path to the "gcc" subdirectory of the source tree
+     (without a trailing slash).  Copy it up to path_to_src_gcc, to
+     avoid selftest.c depending on option-handling.  */
+  path_to_src_gcc = flag_self_test;
+
   long start_time = get_run_time ();
 
   /* Run all the tests, in hand-coded order of (approximate) dependencies:
diff --git a/gcc/selftest.c b/gcc/selftest.c
index cf7031f..2a481ad 100644
--- a/gcc/selftest.c
+++ b/gcc/selftest.c
@@ -198,6 +198,21 @@ read_file (const location &loc, const char *path)
   return result;
 }
 
+/* The path of SRCDIR/gcc.  */
+
+const char *path_to_src_gcc = NULL;
+
+/* Convert a path relative to SRCDIR/gcc/testsuite/selftests
+   to a real path (either absolute, or relative to pwd).
+   The result should be freed by the caller.  */
+
+char *
+locate_file (const char *name)
+{
+  ASSERT_NE (NULL, path_to_src_gcc);
+  return concat (path_to_src_gcc, "/testsuite/selftests/", name, NULL);
+}
+
 /* Selftests for the selftest system itself.  */
 
 /* Sanity-check the ASSERT_ macros with various passing cases.  */
@@ -240,6 +255,18 @@ test_read_file ()
   free (buf);
 }
 
+/* Verify locate_file (and read_file).  */
+
+static void
+test_locate_file ()
+{
+  char *path = locate_file ("example.txt");
+  char *buf = read_file (SELFTEST_LOCATION, path);
+  ASSERT_STREQ ("example of a selftest file\n", buf);
+  free (buf);
+  free (path);
+}
+
 /* Run all of the selftests within this file.  */
 
 void
@@ -248,6 +275,7 @@ selftest_c_tests ()
   test_assertions ();
   test_named_temp_file ();
   test_read_file ();
+  test_locate_file ();
 }
 
 } // namespace selftest
diff --git a/gcc/selftest.h b/gcc/selftest.h
index 86ad14c..8b9c007 100644
--- a/gcc/selftest.h
+++ b/gcc/selftest.h
@@ -187,6 +187,16 @@ class temp_override
 
 extern void forcibly_ggc_collect ();
 
+/* Convert a path relative to SRCDIR/gcc/testsuite/selftests
+   to a real path (either absolute, or relative to pwd).
+   The result should be freed by the caller.  */
+
+extern char *locate_file (const char *path);
+
+/* The path of SRCDIR/gcc.  */
+
+extern const char *path_to_src_gcc;
+
 /* Declarations for specific families of tests (by source file), in
    alphabetical order.  */
 extern void bitmap_c_tests ();
diff --git a/gcc/testsuite/gcc.dg/cpp/pr71591.c b/gcc/testsuite/gcc.dg/cpp/pr71591.c
index e92cb52..0e3d7b1 100644
--- a/gcc/testsuite/gcc.dg/cpp/pr71591.c
+++ b/gcc/testsuite/gcc.dg/cpp/pr71591.c
@@ -1,5 +1,5 @@
 /* PR rtl-optimization/71591 */
 /* { dg-do preprocess } */
-/* { dg-options "-fself-test" } */
+/* { dg-options "-fself-test=fake-value" } */
 
 /* { dg-message "self-tests incompatible with -E" "" { target *-*-* } 0 } */
diff --git a/gcc/testsuite/selftests/example.txt b/gcc/testsuite/selftests/example.txt
new file mode 100644
index 0000000..fbfaa33
--- /dev/null
+++ b/gcc/testsuite/selftests/example.txt
@@ -0,0 +1 @@
+example of a selftest file
-- 
1.8.5.3