buildman: Remove output binaries before building

Buildman reuses build directories from previous builds to avoid the cost
of 'make mrproper' for every build. If the previous build produced an SPL
image but the current one does not, the SPL image will remain and buildman
will think it is a result of building the current board.

Remove these files before building, to avoid this problem.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/buildman/builderthread.py

@@ -13,6 +13,7 @@ from patman import command
 from patman import gitutil
 
 RETURN_CODE_RETRY = -1
+BASE_ELF_FILENAMES = ['u-boot', 'spl/u-boot-spl', 'tpl/u-boot-tpl']
 
 def Mkdir(dirname, parents = False):
     """Make a directory if it doesn't already exist.
@@ -240,6 +241,17 @@ class BuilderThread(threading.Thread):
                 args.extend(self.builder.toolchains.GetMakeArguments(brd))
                 args.extend(self.toolchain.MakeArgs())
 
+                # Remove any output targets. Since we use a build directory that
+                # was previously used by another board, it may have produced an
+                # SPL image. If we don't remove it (i.e. see do_config and
+                # self.mrproper below) then it will appear to be the output of
+                # this build, even if it does not produce SPL images.
+                build_dir = self.builder.GetBuildDir(commit_upto, brd.target)
+                for elf in BASE_ELF_FILENAMES:
+                    fname = os.path.join(out_dir, elf)
+                    if os.path.exists(fname):
+                        os.remove(fname)
+
                 # If we need to reconfigure, do that now
                 if do_config:
                     config_out = ''
@@ -335,7 +347,7 @@ class BuilderThread(threading.Thread):
                 for var in sorted(env.keys()):
                     print('%s="%s"' % (var, env[var]), file=fd)
             lines = []
-            for fname in ['u-boot', 'spl/u-boot-spl']:
+            for fname in BASE_ELF_FILENAMES:
                 cmd = ['%snm' % self.toolchain.cross, '--size-sort', fname]
                 nm_result = command.RunPipe([cmd], capture=True,
                         capture_stderr=True, cwd=result.out_dir,