[PATCHv2] gdb: Allow more control over where to find python libraries

Message ID 20200219162703.17530-1-andrew.burgess@embecosm.com
State New
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  • [PATCHv2] gdb: Allow more control over where to find python libraries
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Commit Message

Andrew Burgess Feb. 19, 2020, 4:27 p.m.
The only change since v1 is rewording of the commit message to make
the aim of the patch clearer.

I still need to make sure that Eli is happy with this change before
I'll consider merging this.

--

The motivation behind this commit is to make it easier to bundle the
Python *.py library files with GDB when statically linking GDB against
libpython.  The Python files will be manually added into the GDB
installation tree, and GDB should be able to find them at run-time.
The installation tree will look like this:

  .
  |-- bin/
  |-- include/
  |-- lib/
  |   `-- python3.8/
  `-- share/

The benefit here is that the entire installation tree can be bundled
into a single archive and copied to another machine with a different
version of Python installed, and GDB will still work, including its
Python support.

In use the new configure options would be used something like this,
first build and install a static Python library:

  mkdir python
  cd python
  # Clone or download Python into a src/ directory.
  mkdir build
  export PYTHON_INSTALL_PATH=$PWD/install
  cd build
  ../src/configure --disable-shared --prefix=$PYTHON_INSTALL_PATH
  make
  make install

Now build and install GDB:

  mkdir binutils-gdb
  cd binutils-gdb
  # Clone or download GDB into a src/ directory.
  mkdir build
  export GDB_INSTALL_DIR=$PWD/install
  cd build
  ../src/configure \
      --prefix=$GDB_INSTALL_DIR \
      --with-python=$PYTHON_INSTALL_PATH/bin/python3 \
      --with-python-libdir=$GDB_INSTALL_DIR/lib
  make all-gdb
  make install-gdb

Finally, copy the Python libraries into the GDB install:

  cp -r $PYTHON_INSTALL_DIR/lib/python3.8/ $GDB_INSTALL_DIR/lib

After this the Python src, build, and install directories are no
longer needed and can be deleted.

If the new --with-python-libdir option is not used then the existing
behaviour is left unchanged, GDB will look for the Python libraries in
the lib/ directory within the python path.  The concatenation of the
python prefix and the string 'lib/' is now done at configure time,
rather than at run time in GDB as it was previous, however, this was
never something that the user had dynamic control over, so there's no
loss of functionality.

gdb/ChangeLog:

	* config.in: Regenerate.
	* configure: Regenerate.
	* configure.ac: Add --with-python-libdir option.
	* main.c: Use WITH_PYTHON_LIBDIR.
---
 gdb/ChangeLog    |  7 +++++++
 gdb/config.in    |  8 ++++++++
 gdb/configure    | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 gdb/configure.ac | 24 ++++++++++++++++++++++++
 gdb/main.c       | 11 +++--------
 5 files changed, 91 insertions(+), 8 deletions(-)

-- 
2.14.5

Comments

Eli Zaretskii Feb. 19, 2020, 5:08 p.m. | #1
> From: Andrew Burgess <andrew.burgess@embecosm.com>

> Cc: Andrew Burgess <andrew.burgess@embecosm.com>

> Date: Wed, 19 Feb 2020 16:27:03 +0000

> 

> I still need to make sure that Eli is happy with this change


I am, thanks.
Tom Tromey Feb. 20, 2020, 4:59 p.m. | #2
>>>>> "Andrew" == Andrew Burgess <andrew.burgess@embecosm.com> writes:


Andrew> The only change since v1 is rewording of the commit message to make
Andrew> the aim of the patch clearer.

FWIW, we have a similar situation; one additional thing we do is arrange
to call Py_SetPythonHome to ensure that the user's PYTHONPATH doesn't
break gdb.

It would be good if the standard gdb did this (I think someone filed
something like this in bugzilla), but I'm not sure it can be done in a
way that's consistent with gdb's other goals, like relocatability.

Tom
Andrew Burgess Feb. 20, 2020, 7:22 p.m. | #3
* Tom Tromey <tromey@adacore.com> [2020-02-20 09:59:56 -0700]:

> >>>>> "Andrew" == Andrew Burgess <andrew.burgess@embecosm.com> writes:

> 

> Andrew> The only change since v1 is rewording of the commit message to make

> Andrew> the aim of the patch clearer.

> 

> FWIW, we have a similar situation; one additional thing we do is arrange

> to call Py_SetPythonHome to ensure that the user's PYTHONPATH doesn't

> break gdb.

> 

> It would be good if the standard gdb did this (I think someone filed

> something like this in bugzilla), but I'm not sure it can be done in a

> way that's consistent with gdb's other goals, like relocatability.


I suspect these bugs:

  https://sourceware.org/bugzilla/show_bug.cgi?id=23014
  https://sourceware.org/bugzilla/show_bug.cgi?id=22503

are the ones.

I'll need to think a bit more about what the implications are of
making this change...

Thanks,
Andrew

Patch

diff --git a/gdb/config.in b/gdb/config.in
index cb886ba8e1a..9c5c1ce834d 100644
--- a/gdb/config.in
+++ b/gdb/config.in
@@ -649,6 +649,10 @@ 
 /* Define as the return type of ptrace. */
 #undef PTRACE_TYPE_RET
 
+/* Define if the python lib directory should be relocated when GDB is moved.
+   */
+#undef PYTHON_LIBDIR_RELOCATABLE
+
 /* Define if the python directory should be relocated when GDB is moved. */
 #undef PYTHON_PATH_RELOCATABLE
 
@@ -752,6 +756,10 @@ 
 /* Define if the PPC simulator is being linked in. */
 #undef WITH_PPC_SIM
 
+/* Directory containing Python's standard libraries from --with-python-libdir.
+   */
+#undef WITH_PYTHON_LIBDIR
+
 /* Define if --with-python provides a path, either directly or via
    python-config.py --exec-prefix. */
 #undef WITH_PYTHON_PATH
diff --git a/gdb/configure b/gdb/configure
index 4f2d7f8f232..ea1198ba63a 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -887,6 +887,7 @@  with_libexpat_prefix
 with_mpfr
 with_libmpfr_prefix
 with_python
+with_python_libdir
 with_guile
 enable_source_highlight
 with_intel_pt
@@ -1615,6 +1616,8 @@  Optional Packages:
   --without-libmpfr-prefix     don't search for libmpfr in includedir and libdir
   --with-python[=PYTHON]  include python support
                           (auto/yes/no/<python-program>)
+  --with-python-libdir[=DIR]
+                          search for python's libraries in DIR
   --with-guile[=GUILE]    include guile support
                           (auto/yes/no/<guile-version>/<pkg-config-program>)
   --with-intel-pt         include Intel Processor Trace support (auto/yes/no)
@@ -10606,6 +10609,21 @@  _ACEOF
   fi
 fi
 
+
+# Check whether --with-python-libdir was given.
+if test "${with_python_libdir+set}" = set; then :
+  withval=$with_python_libdir;
+else
+
+    # If no python libdir is specified then select one based on
+    # python's prefix path.
+    if test -n "${python_prefix}"; then
+      with_python_libdir=${python_prefix}/lib
+    fi
+
+fi
+
+
 if test "${have_libpython}" != no; then
 
 $as_echo "#define HAVE_PYTHON 1" >>confdefs.h
@@ -10616,6 +10634,37 @@  $as_echo "#define HAVE_PYTHON 1" >>confdefs.h
   CONFIG_INSTALL="$CONFIG_INSTALL install-python"
   ENABLE_CFLAGS="$ENABLE_CFLAGS \$(SUBDIR_PYTHON_CFLAGS)"
 
+  if test -n "${with_python_libdir}"; then
+
+cat >>confdefs.h <<_ACEOF
+#define WITH_PYTHON_LIBDIR "${with_python_libdir}"
+_ACEOF
+
+
+  if test "x$exec_prefix" = xNONE || test "x$exec_prefix" = 'x${prefix}'; then
+     if test "x$prefix" = xNONE; then
+     	test_prefix=/usr/local
+     else
+	test_prefix=$prefix
+     fi
+  else
+     test_prefix=$exec_prefix
+  fi
+  value=0
+  case ${with_python_libdir} in
+     "${test_prefix}"|"${test_prefix}/"*|\
+	'${exec_prefix}'|'${exec_prefix}/'*)
+     value=1
+     ;;
+  esac
+
+cat >>confdefs.h <<_ACEOF
+#define PYTHON_LIBDIR_RELOCATABLE $value
+_ACEOF
+
+
+  fi
+
   # Flags needed to compile Python code (taken from python-config --cflags).
   # We cannot call python-config directly because it will output whatever was
   # used when compiling the Python interpreter itself, including flags which
diff --git a/gdb/configure.ac b/gdb/configure.ac
index 335971fdf66..a51c5eda6b5 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -890,6 +890,24 @@  else
   fi
 fi
 
+dnl Use --with-python-libdir to control where GDB looks for the Python
+dnl libraries.
+dnl
+dnl If this is not given then the default will be based on the value
+dnl passed to --with-python, which is in the python_prefix variable.
+dnl If the --with-python option wasn't given then the default value in
+dnl python_prefix is based on running the 'gdb/python/python-config
+dnl --exec-prefix' script.
+AC_ARG_WITH(python-libdir,
+  AS_HELP_STRING([--with-python-libdir@<:@=DIR@:>@], [search for python's libraries in DIR]),
+  [],[
+    # If no python libdir is specified then select one based on
+    # python's prefix path.
+    if test -n "${python_prefix}"; then
+      with_python_libdir=${python_prefix}/lib
+    fi
+  ])
+
 if test "${have_libpython}" != no; then
   AC_DEFINE(HAVE_PYTHON, 1, [Define if Python interpreter is being linked in.])
   CONFIG_OBS="$CONFIG_OBS \$(SUBDIR_PYTHON_OBS)"
@@ -898,6 +916,12 @@  if test "${have_libpython}" != no; then
   CONFIG_INSTALL="$CONFIG_INSTALL install-python"
   ENABLE_CFLAGS="$ENABLE_CFLAGS \$(SUBDIR_PYTHON_CFLAGS)"
 
+  if test -n "${with_python_libdir}"; then
+    AC_DEFINE_UNQUOTED(WITH_PYTHON_LIBDIR, "${with_python_libdir}",
+		       [Directory containing Python's standard libraries from --with-python-libdir.])
+    GDB_AC_DEFINE_RELOCATABLE(PYTHON_LIBDIR, [python lib], ${with_python_libdir})
+  fi
+
   # Flags needed to compile Python code (taken from python-config --cflags).
   # We cannot call python-config directly because it will output whatever was
   # used when compiling the Python interpreter itself, including flags which
diff --git a/gdb/main.c b/gdb/main.c
index d5e5a678baa..a03ed8117ab 100644
--- a/gdb/main.c
+++ b/gdb/main.c
@@ -575,14 +575,9 @@  captured_main_1 (struct captured_main_args *context)
   gdb_datadir = relocate_gdb_directory (GDB_DATADIR,
 					GDB_DATADIR_RELOCATABLE);
 
-#ifdef WITH_PYTHON_PATH
-  {
-    /* For later use in helping Python find itself.  */
-    char *tmp = concat (WITH_PYTHON_PATH, SLASH_STRING, "lib", (char *) NULL);
-
-    python_libdir = relocate_gdb_directory (tmp, PYTHON_PATH_RELOCATABLE);
-    xfree (tmp);
-  }
+#ifdef WITH_PYTHON_LIBDIR
+  python_libdir = relocate_gdb_directory (WITH_PYTHON_LIBDIR,
+					  PYTHON_LIBDIR_RELOCATABLE);
 #endif
 
 #ifdef RELOC_SRCDIR