[RFC/commmit] [testsuite/Ada] stop using project files when building test programs

[Joel Brobecker <brobecker at adacore dot com>]

Hello,

Below is a fairly straightforward change, except maybe for the use
of try / finally, which requires TCL version 8.6, released Dec 2012.
I think it's a reasonable requirement; any objection?

Thanks!

-------------------------------------------------------------

The current approach when building Ada programs for testing is
based on the use of a project file (testsuite/gdb.ada/gnat_ada.gpr).
To do that, we pass a number of additional arguments to target_compile,
one of them being the project file (via "-P/path/to/gnat_ada.gpr").
This used to work well-enough, but AdaCore is currently working towards
removing project-file support from gnatmake (the prefered tool for
using project files is gprbuild). So, we need to either switch
the compilation to gprbuild, or stop using project files.

First, using gprbuild is not always what users will be using to
build their applications. So having the option of using gnatmake
provides more flexibility towards exactly reproducing past bugs.
If we ever need a testcase that requires the use of gprbuild, then
I believe support for a new target needs to be added to dejagnu's
target_compile.

Also, the only real reason behind using a project file in the first
place is that we wanted to make it easy to specify the directory
where all compilation artifacts get stored. This is a consequence
of the organization choice we made for gdb.ada to keep each testcase
well organized. It is very easy to achieve that goal without using
project files.

This is therefore what this patch does: It change gdb_compile_ada
to build any program using gnatmake without using a project file
(by temporarily changing the current working directory).

There is a small (beneficial) side-effect; in the situation where
GDB is built in-tree, gnatmake is called as...

        % gnatmake [...] unit.adb

... which means that the debugging info in unit.o will say contain
a filename whose name is 'unit.adb', rather than '/path/to/unit.adb'.
This also better matches what users might typically do. But the side-
effect is that the unit name in the GDB output is not always a full
path. This patch tweaks a couple of testcases to make the path part
optional.

Note that this patch requires TCL version 8.6, which was released
Dec 2012.

gdb/testsuite:

        * lib/ada.exp (gdb_compile_ada): Reimplement avoiding the use
        of project files.
        * gdb.ada/gnat_ada.gpr: Delete.
        * gdb.ada/cond_lang.exp: Adjust test to make path before
        filename optional.
        * gdb.ada/small_reg_param.exp: Likewise.

Tested on x86_64-linux, with both in-tree and out-of-tree builds.
---
 gdb/testsuite/gdb.ada/cond_lang.exp       |  2 +-
 gdb/testsuite/gdb.ada/gnat_ada.gpr        | 25 -------------------------
 gdb/testsuite/gdb.ada/small_reg_param.exp |  2 +-
 gdb/testsuite/lib/ada.exp                 | 20 ++++++++++++++++----
 4 files changed, 18 insertions(+), 31 deletions(-)
 delete mode 100644 gdb/testsuite/gdb.ada/gnat_ada.gpr

diff --git a/gdb/testsuite/gdb.ada/cond_lang.exp b/gdb/testsuite/gdb.ada/cond_lang.exp
index 0dfb9e3..7c3ad6e 100644
--- a/gdb/testsuite/gdb.ada/cond_lang.exp
+++ b/gdb/testsuite/gdb.ada/cond_lang.exp
@@ -39,7 +39,7 @@ gdb_test "show lang" \
 # current language mode is auto, and the breakpoint is inside Ada code.
 set bp_location [gdb_get_line_number "STOP" ${testdir}/mixed.adb]
 gdb_test "break mixed.adb:${bp_location} if light = green" \
-         "Breakpoint \[0-9\]* at .*: file .*/mixed.adb, line \[0-9\]*\\."
+         "Breakpoint \[0-9\]* at .*: file (.*/)?mixed.adb, line \[0-9\]*\\."
 
 # Now, continue until we hit the breakpoint.  If the condition is
 # evaluated correctly, the first hit will be ignored, and the debugger
diff --git a/gdb/testsuite/gdb.ada/gnat_ada.gpr b/gdb/testsuite/gdb.ada/gnat_ada.gpr
deleted file mode 100644
index 2736206..0000000
--- a/gdb/testsuite/gdb.ada/gnat_ada.gpr
+++ /dev/null
@@ -1,25 +0,0 @@
---  Copyright 2004-2015 Free Software Foundation, Inc.
---
---  This program is free software; you can redistribute it and/or modify
---  it under the terms of the GNU General Public License as published by
---  the Free Software Foundation; either version 3 of the License, or
---  (at your option) any later version.
---
---  This program is distributed in the hope that it will be useful,
---  but WITHOUT ANY WARRANTY; without even the implied warranty of
---  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
---  GNU General Public License for more details.
---
---  You should have received a copy of the GNU General Public License
---  along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
---  This project file allows us to control the location where the
---  compilation artifacts produced when building the Ada examples
---  are stored.
-
-project Gnat_Ada is
-
-   for Source_Dirs use (external ("SRC"));
-   for Object_Dir use external ("OBJ");
-
-end Gnat_Ada;
diff --git a/gdb/testsuite/gdb.ada/small_reg_param.exp b/gdb/testsuite/gdb.ada/small_reg_param.exp
index bd5cfd6..0a3b972 100644
--- a/gdb/testsuite/gdb.ada/small_reg_param.exp
+++ b/gdb/testsuite/gdb.ada/small_reg_param.exp
@@ -33,7 +33,7 @@ gdb_breakpoint "call_me"
 # Continue until we hit the breakpoint inside `Call_Me'.  We verify
 # that the parameter value is correct.
 gdb_test "continue" \
-    "Breakpoint .*, pck\\.call_me \\(w=(w@entry=)?50\\) at .*/pck.adb:.*" \
+    "Breakpoint .*, pck\\.call_me \\(w=(w@entry=)?50\\) at (.*)?/pck.adb:.*" \
     "continue to call_me"
 
 # And just to make sure, we also verify that the parameter value
diff --git a/gdb/testsuite/lib/ada.exp b/gdb/testsuite/lib/ada.exp
index 6a1e192..b8a1724 100644
--- a/gdb/testsuite/lib/ada.exp
+++ b/gdb/testsuite/lib/ada.exp
@@ -21,12 +21,24 @@ proc gdb_compile_ada {source dest type options} {
     set gprdir [file dirname $srcdir]
     set objdir [file dirname $dest]
 
+    # Although strictly not necessary, we force the recompilation
+    # of all units (additional_flags=-f).  This is what is done
+    # when using GCC to build programs in the other languages,
+    # and it avoids using a stray objfile file from a long-past
+    # run, for instance.
     append options " ada"
-    append options " additional_flags=-P$gprdir/gnat_ada"
-    append options " additional_flags=-XSRC=[file tail $srcdir]"
-    append options " additional_flags=-XOBJ=$objdir"
+    append options " additional_flags=-f"
+    append options " additional_flags=-I$srcdir"
 
-    set result [target_compile [file tail $source] $dest $type $options]
+    # Run target_compile from the directory where we want the object
+    # files and the executable to be written.
+    set saved_cwd [pwd]
+    try {
+        cd $objdir
+        set result [target_compile [file tail $source] $dest $type $options]
+    } finally {
+        cd $saved_cwd
+    }
 
     # The Ada build always produces some output, even when the build
     # succeeds. Thus, we can not use the output the same way we do in
-- 
2.1.4