sb: Add support to search for a suitable version of python.

The command python has been removed from upstream python and python2
and python3 is now used. This patch wraps the commands in a shell
script that locates a suitable python to run.

Updates #3537

1 files changed, 103 insertions, 2 deletions

diff --git a/source-builder/config/gdb-common-1.cfg b/source-builder/config/gdb-common-1.cfg
index fe4dbaf..30fdf90 100644
--- a/source-builder/config/gdb-common-1.cfg
+++ b/source-builder/config/gdb-common-1.cfg
@@ -5,6 +5,103 @@
 #
 
 #
+# Python
+#
+# GDB uses python internally so we need to link to a suitable python
+# dev kit. The dev kit for python is the header and a library. These
+# files are versioned where the header file is located in a directory
+# based on:
+#
+#  pythonM.m/Python.h
+#
+# where 'M' is the major version number and 'm' is the minor verison
+# number. The library is:
+#
+#  libpythonM.m.a
+#
+# The python command is 'pythonM' which means we need to query it for
+# the minor number.
+#
+# The python running the RSB may not be suitable, for example a MSC,
+# MSYS or Cygwin version on Windows when we want the MinGW python dev
+# file. A specific version cannot be forced because older versions of
+# GDB can only link to 'python2'.
+#
+# Host support can perform a complex query of the system, for example
+# Windows and set '%{gdb_python2}' and '%{gdb_python3}' with the full
+# path to that version's executable.
+#
+# A configuration of GDB can set the version required by setting
+# '%{gdb-python-version}' to the versions command, eg python2.
+#
+# The procedure is:
+#
+# 1. If the macros '%{gdb_python2}' or '%{gdb_python3}' are present
+#    use that path they contain. Assume the path is valid.
+#
+# 2. Does the version of gdb specify a version of python that must be
+#    used. Override with '%define gdb-python-version python2'.
+#
+# 3. Search for 'python2' and if not found search for 'python3'.
+#
+%if %{defined gdb-python2}
+  %define gdb-enable-python %{gdb_python2}
+%else
+  %if %{defined gdb-python3}
+    %define gdb-enable-python %{gdb_python3}
+  %else
+    %if %{defined gdb-python-version}
+      %define gdb-enable-python %(command -v %{gdb-python-version || true})
+    %else
+      %define gdb-enable-python %(command -v python2 || true)
+      %if %{gdb-enable-python} == %{nil}
+        %define gdb-enable-python %(command -v python3 || true)
+      %endif
+      %if %{gdb-enable-python} == %{nil}
+          %define gdb-enable-python %(command -v python || true})
+      %endif
+    %endif
+    %if %{gdb-enable-python} == %{nil}
+      %error "gdb: python: no valid version of python found"
+    %endif
+  %endif
+%endif
+
+#
+# Get the Python's major and minor version from the python
+# command. The headers and libraries are installed under a major/minor
+# (mm) version path and name.
+#
+# The library file name can vary across the hosts so wildcard the search.
+#
+%define gdb-python-ver-mm %(%{gdb-enable-python} --version 2>&1 | sed -e 's/.* //g' | rev | cut -d'.' -f2- | rev)
+%define gdb-python-ver-header python%{gdb-python-ver-mm}/Python.h
+%define gdb-python-ver-lib libpython%{gdb-python-ver-mm}.*
+%if %{host_includes} == %{nil}
+  %define gdb-host-incs %{nil}
+%else
+  %define gdb-host-incs -I '%{host_includes}'
+%endif
+%define gdb-python-header-check %(%{_sbdir}/sb/rtems-build-dep -c %{__cc} %{gdb-host-incs} -H %{gdb-python-ver-header})
+%if %{gdb-python-header-check} == not-found
+  %error "gdb: python: header file not found: %{gdb-python-ver-header}, please install"
+%endif
+#
+# Too hard to find on MacOS (darwin), the header is good enough.
+#
+%ifnos darwin
+  %if %{host_ldflags} == %{nil}
+    %define gdb-host-libs %{nil}
+  %else
+    %define gdb-host-libs -L '%{host_ldflags}'
+  %endif
+  %define gdb-python-lib-check %(%{_sbdir}/sb/rtems-build-dep -c %{__cc} %{gdb-host-libs} -l %{gdb-python-ver-lib})
+  %if %{gdb-python-lib-check} == not-found
+    %error "gdb: python: library file not found: %{gdb-python-ver-lib}, please install"
+  %endif
+%endif
+
+#
 # See if the simulator has been disabled for Windows.
 #
 # Build using the system's readline, it is in better shape
@@ -41,7 +138,7 @@ Name:      %{_target}-gdb-%{gdb_version}-%{_host}-%{release}
 Summary:   GDB v%{gdb_version} for target %{_target} on host %{_host}
 Version:   %{gdb_version}
 Release:   %{release}
-URL: 	   http://www.gnu.org/software/gdb/
+URL:       http://www.gnu.org/software/gdb/
 BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
 
 #
@@ -70,7 +167,11 @@ BuildRoot: %{_tmppath}/%{name}-root-%(%{__id_u} -n)
 %if %{defined with_python_path}
   %define with_python_option --with-python=%{with_python_path}
 %else
-  %define with_python_option --with-python
+  %if %{defined gdb-enable-python}
+    %define with_python_option --with-python=%{gdb-enable-python}
+  %else
+    %define with_python_option --with-python
+  %endif
 %endif
 
 #