The probe of gdb is done in 'configure' and the full path is passed to
meson.build via the -Dgdb=option.

Meson then can pass the location of GDB to the test via an environment
variable: QEMU_TEST_GDB.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
---
 configure                     | 2 ++
 meson_options.txt             | 2 ++
 scripts/meson-buildoptions.sh | 2 ++
 tests/functional/meson.build  | 6 ++++++
 4 files changed, 12 insertions(+)

diff --git a/configure b/configure
index 0f7eb95586..7226ddd589 100755
--- a/configure
+++ b/configure
@@ -1984,6 +1984,8 @@ if test "$skip_meson" = no; then
   test -n "${LIB_FUZZING_ENGINE+xxx}" && meson_option_add "-Dfuzzing_engine=$LIB_FUZZING_ENGINE"
   test "$plugins" = yes && meson_option_add "-Dplugins=true"
   test "$tcg" != enabled && meson_option_add "-Dtcg=$tcg"
+  test -n "$gdb_bin" && meson_option_add "-Dgdb=$gdb_bin"
+
   run_meson() {
     NINJA=$ninja $meson setup "$@" "$PWD" "$source_path"
   }
diff --git a/meson_options.txt b/meson_options.txt
index fff1521e58..5bb41bcbc4 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -36,6 +36,8 @@ option('trace_file', type: 'string', value: 'trace',
 option('coroutine_backend', type: 'combo',
        choices: ['ucontext', 'sigaltstack', 'windows', 'wasm', 'auto'],
        value: 'auto', description: 'coroutine backend to use')
+option('gdb', type: 'string', value: '',
+       description: 'Path to GDB')
 
 # Everything else can be set via --enable/--disable-* option
 # on the configure script command line.  After adding an option
diff --git a/scripts/meson-buildoptions.sh b/scripts/meson-buildoptions.sh
index 0ebe6bc52a..f4bd21220e 100644
--- a/scripts/meson-buildoptions.sh
+++ b/scripts/meson-buildoptions.sh
@@ -58,6 +58,7 @@ meson_options_help() {
   printf "%s\n" '  --enable-ubsan           enable undefined behaviour sanitizer'
   printf "%s\n" '  --firmwarepath=VALUES    search PATH for firmware files [share/qemu-'
   printf "%s\n" '                           firmware]'
+  printf "%s\n" '  --gdb=VALUE              Path to GDB'
   printf "%s\n" '  --iasl=VALUE             Path to ACPI disassembler'
   printf "%s\n" '  --includedir=VALUE       Header file directory [include]'
   printf "%s\n" '  --interp-prefix=VALUE    where to find shared libraries etc., use %M for'
@@ -323,6 +324,7 @@ _meson_option_parse() {
     --disable-fuzzing) printf "%s" -Dfuzzing=false ;;
     --enable-gcrypt) printf "%s" -Dgcrypt=enabled ;;
     --disable-gcrypt) printf "%s" -Dgcrypt=disabled ;;
+    --gdb=*) quote_sh "-Dgdb=$2" ;;
     --enable-gettext) printf "%s" -Dgettext=enabled ;;
     --disable-gettext) printf "%s" -Dgettext=disabled ;;
     --enable-gio) printf "%s" -Dgio=enabled ;;
diff --git a/tests/functional/meson.build b/tests/functional/meson.build
index 2a0c5aa141..725630d308 100644
--- a/tests/functional/meson.build
+++ b/tests/functional/meson.build
@@ -77,6 +77,12 @@ foreach speed : ['quick', 'thorough']
     test_env.set('PYTHONPATH', meson.project_source_root() / 'python:' +
                                meson.current_source_dir())
 
+    # Define the GDB environment variable if gdb is available.
+    gdb = get_option('gdb')
+    if gdb != ''
+      test_env.set('QEMU_TEST_GDB', gdb)
+    endif
+
     foreach test : target_tests
       testname = '@0@-@1@'.format(target_base, test)
       if fs.exists('generic' / 'test_' + test + '.py')
-- 
2.34.1