Test builds with minimal-printf and optional check for floats post-build

Unless specified otherwise, run the example projects compilation test
using the minimal-printf extension profile. Also add an optional
argument to the `compile` subcommand to perform post-build checks.

The only post build check supported at the moment is checking for
floating point symbol in the object file. The floating point check
excludes example projects which currently still use floating points

tools/test/examples/examples.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 """
 Copyright (c) 2017-2019 ARM Limited. All rights reserved.
 
@@ -27,17 +28,20 @@
 """ import and bulid a bunch of example programs """
 
 ROOT = abspath(dirname(dirname(dirname(dirname(__file__)))))
-sys.path.insert(0, ROOT)
+DEFAULT_BUILD_PROFILES = [
+    "develop",
+    "mbed-os/tools/profiles/extensions/minimal-printf.json",
+]
+sys.path.append(ROOT)
 
 from tools.utils import argparse_force_uppercase_type
 from tools.utils import argparse_many
 from tools.build_api import get_mbed_official_release
 import examples_lib as lib
 from examples_lib import SUPPORTED_TOOLCHAINS, SUPPORTED_IDES
 
-def main():
-    """Entry point"""
-
+def parse_args():
+    """Parse the arguments passed to the script."""
     official_targets = get_mbed_official_release("5")
     official_target_names = [x[0] for x in official_targets]
 
@@ -72,10 +76,21 @@ def main():
                                 argparse_force_uppercase_type(
                                     official_target_names, "MCU")),
                             default=official_target_names)
+    compile_cmd.add_argument(
+        "--post-checks",
+        nargs='+',
+        choices=list(lib.SUPPORTED_POST_BUILD_CHECKS.keys()),
+        default=None,
+        help="specify check operation(s) to perform after compiling.",
+    )
 
-    compile_cmd.add_argument("--profile",
-                             help=("build profile file"),
-                             metavar="profile")
+    compile_cmd.add_argument(
+        "--profiles",
+        nargs='+',
+        default=DEFAULT_BUILD_PROFILES,
+        metavar="profile",
+        help=f"build profile file(s). default = {DEFAULT_BUILD_PROFILES}",
+    )
 
     compile_cmd.add_argument("-v", "--verbose",
                              action="store_true",
@@ -84,7 +99,7 @@ def main():
                              help="Verbose diagnostic output")
 
     export_cmd = subparsers.add_parser("export")
-    export_cmd.set_defaults(fn=do_export),
+    export_cmd.set_defaults(fn=do_export)
     export_cmd.add_argument(
         "ide", nargs="*", default=SUPPORTED_IDES,
         type=argparse_force_uppercase_type(SUPPORTED_IDES,
@@ -97,7 +112,13 @@ def main():
                                 argparse_force_uppercase_type(
                                     official_target_names, "MCU")),
                             default=official_target_names)
-    args = parser.parse_args()
+    return parser.parse_args()
+
+
+def main():
+    """Entry point"""
+
+    args = parse_args()
     config = json.load(open(os.path.join(os.path.dirname(__file__),
                                args.config)))
 
@@ -137,12 +158,21 @@ def do_deploy(_, config, examples):
 def do_compile(args, config, examples):
     """Do the compile step"""
     results = {}
-    results = lib.compile_repos(config, args.toolchains, args.mcu, args.profile, args.verbose, examples)
+    results = lib.compile_repos(
+        config,
+        args.toolchains,
+        args.mcu,
+        args.profiles,
+        args.verbose,
+        examples,
+        args.post_checks,
+    )
     lib.print_summary(results)
     failures = lib.get_num_failures(results)
     print("Number of failures = %d" % failures)
-    return failures 
-
+    return failures
+
+
 def do_versionning(args, config, examples):
     """ Test update the mbed-os to the version specified by the tag """
     return lib.update_mbedos_version(config, args.tag, examples)

tools/test/examples/examples_lib.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 """
 Copyright (c) 2017-2019 ARM Limited. All rights reserved.
 
@@ -15,6 +16,7 @@
 See the License for the specific language governing permissions and
 limitations 
 """
+import json
 import os
 from os.path import dirname, abspath, basename, join, normpath
 import os.path
@@ -30,8 +32,16 @@
 
  """
 
+
+EXECUTABLE_ANALYSIS_TOOLS_PATH = join(
+    os.path.dirname(__file__),
+    "../../executable_analysis_tools/",
+)
+sys.path.append(EXECUTABLE_ANALYSIS_TOOLS_PATH)
+import elf_float_checker
+
 ROOT = abspath(dirname(dirname(dirname(dirname(__file__)))))
-sys.path.insert(0, ROOT)
+sys.path.append(ROOT)
 
 from tools.build_api import get_mbed_official_release
 from tools.targets import TARGET_MAP
@@ -349,7 +359,7 @@ def status(message):
     return results
 
 
-def compile_repos(config, toolchains, targets, profile, verbose, examples):
+def compile_repos(config, toolchains, targets, profiles, verbose, examples, post_checks):
     """Compiles combinations of example programs, targets and compile chains.
 
        The results are returned in a [key: value] dictionary format:
@@ -388,6 +398,7 @@ def compile_repos(config, toolchains, targets, profile, verbose, examples):
             test_example = True
         else:
             test_example = False
+
         if example['compile']:
             for repo_info in get_repo_list(example):
                 name = basename(repo_info['repo'])
@@ -399,28 +410,54 @@ def compile_repos(config, toolchains, targets, profile, verbose, examples):
                                                                 example['features']):
 
                     build_command = ["mbed-cli", "compile", "-t", toolchain, "-m", target] + (['-vv'] if verbose else [])
-                    if profile:
-                        build_command.append("--profile")
-                        build_command.append(profile)
+                    if profiles:
+                        for profile in profiles:
+                            build_command.extend(["--profile", profile])
 
                     print("Compiling [%s] for [%s] with toolchain [%s]\n\n>  %s" % (name, target, toolchain, " ".join(build_command)))
 
-                    proc = subprocess.Popen(build_command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+                    if (
+                        post_checks
+                        and POST_BUILD_CHECK_FLOATS in post_checks
+                        and name not in POST_BUILD_CHECK_FLOATS_EXCLUDED_EXAMPLES
+                    ):
+                        # Disable floating point support for minimal-printf if
+                        # a post build check for minimal-printf is specified.
+                        has_float_support = "false"
+                    else:
+                        has_float_support = "true"
+
+                    _set_minimal_printf_floats_status(has_float_support)
+
+                    proc = subprocess.run(
+                        build_command,
+                        stdin=None,
+                        stdout=subprocess.PIPE,
+                        stderr=subprocess.PIPE,
+                    )
+
+                    std_out = proc.stdout.decode()
+                    std_err = proc.stderr.decode()
 
-                    std_out, std_err = proc.communicate()
-                    std_out = std_out.decode('utf-8')
                     print ("\n#### STDOUT ####\n%s\n#### STDERR ####\n%s\n#### End of STDOUT/STDERR ####\n" % (std_out,std_err))
-                    
+
                     if test_example:
                         log = example['compare_log'].pop(0)
                         # example['compare_log'] is a list of log file/files, which matches each examples/sub-examples from same repo. 
                         # pop the log file out of list regardless the compilation for each example pass of fail
                         image = fetch_output_image(std_out)
                         if image:
                             image_info = [{"binary_type": "bootable","path": normpath(join(name,image)),"compare_log":log}]
+                            if post_checks:
+                                try:
+                                    _perform_post_build_checks(
+                                        name, post_checks, dirname(image)
+                                    )
+                                except PostBuildCheckFailureError as error:
+                                    failures.append(str(error))
                         else:
                             print ("Warning: could not find built image for example %s" % name)
-                        
+
                     example_summary = "{} {} {}".format(name, target, toolchain)
                     if proc.returncode:
                         failures.append(example_summary)
@@ -494,4 +531,81 @@ def fetch_output_image(output):
             image = lines[index][7:]
             if os.path.isfile(image):
                 return image
-    return False
+    return False
+
+
+def _perform_post_build_checks(example_name, checks, elf_dir_path):
+    """
+    Perform post build checks.
+
+    The function raises a PostBuildCheckFailureError exceptions if an error is
+    encountered.
+    """
+    if not checks:
+        raise PostBuildCheckFailureError("No post build check specified")
+
+    # Find the elf file
+    elf_file = None
+    for dirpath, _, filenames in os.walk(elf_dir_path):
+        for filename in filenames:
+            if filename.endswith(".elf"):
+                elf_file = os.path.join(dirpath, filename)
+
+    if not elf_file:
+        raise PostBuildCheckFailureError(
+            "Cannot find ELF file in {}".format(elf_dir_path)
+        )
+
+    for check in set(checks):
+        SUPPORTED_POST_BUILD_CHECKS[check](example_name, elf_file)
+
+
+def _set_minimal_printf_floats_status(status):
+    """
+    Enable or disable floating point support in minimal-printf.
+
+    Pass the string `true` or `false` to enable or disable floating point.
+    """
+    with open(
+        os.path.join(ROOT, "platform", "mbed_lib.json"), "r"
+    ) as platform_lib_file:
+        data = json.load(platform_lib_file)
+
+    data["config"]["minimal-printf-enable-floating-point"]["value"] = status
+
+    with open(
+        os.path.join(ROOT, "platform", "mbed_lib.json"), "w"
+    ) as platform_lib_file:
+        json.dump(data, platform_lib_file, indent=4)
+
+
+# Post-build check functions should be listed below and must raise a
+# a PostBuildCheckFailureError in case of failure
+
+def _post_build_check_floating_point(example_name, elf_file):
+    """Check if there are floating points in the executable."""
+
+    if example_name in POST_BUILD_CHECK_FLOATS_EXCLUDED_EXAMPLES:
+        return
+
+    float_symbols = elf_float_checker.check_float_symbols(elf_file)
+
+    if float_symbols:
+        raise PostBuildCheckFailureError(
+            "Floating point symbols found in executable: {}".format(
+                float_symbols
+            )
+        )
+
+# Specify the example project that should not be checked for floating point because they will always fail
+POST_BUILD_CHECK_FLOATS_EXCLUDED_EXAMPLES = [
+    "mbed-os-example-lorawan", # The LoRaWAN is not actively worked on and we are consideing dropping LoRaWAN example from Mbed OS examples.
+    "nanostack-border-router", # nanostack-border-router example depends on ST changes to stm-spirit1-rf-driver library.
+]
+POST_BUILD_CHECK_FLOATS = "FLOATS"
+SUPPORTED_POST_BUILD_CHECKS = {
+    POST_BUILD_CHECK_FLOATS : _post_build_check_floating_point
+}
+
+class PostBuildCheckFailureError(Exception):
+    """An exception to indicate that a post build check failed."""