Introduce lib-embedded-gcov

Config.uk

@@ -0,0 +1,38 @@
+menuconfig LIBEMBEDDEDGCOV
+	bool "embedded-gcov"
+	default n
+
+if LIBEMBEDDEDGCOV
+config LIBEMBEDDEDGCOV_PROVIDE_CALL_CONSTRUCTORS
+	bool "Provide call constructors"
+	help
+	  In most systems __gcov_init() is called on startup. If you are
+	  running on a non-standard startup environment you can enable this
+	  option, and gcov-embedded will provide __gcov_call_constructors()
+	  that you can run manually. For that you will need to define __ctor_list
+	  and __ctor_end. For more info refer to the embedded-gcov documentation.
+	default n
+
+config LIBEMBEDDEDGCOV_PRINT_STATUS
+	bool "Print status to console"
+	help
+	  Print status and error messages to the serial console. If the
+	  coverage data output is set to console, status is always printed
+	  to the console.
+	default n
+
+config LIBEMBEDDEDGCOV_USE_MALLOC
+	bool "Use malloc"
+	depends on LIBUKALLOC
+	help
+	  Use malloc to get space for coverage data"
+	default y
+
+choice LIBEMBEDDEDGCOV_OUTPUT
+	prompt "Coverage data output"
+	default LIBEMBEDDEDGCOV_OUTPUT_SERIAL_HEXDUMP
+config LIBEMBEDDEDGCOV_OUTPUT_SERIAL_HEXDUMP
+	bool "Console"
+endchoice
+
+endif

Makefile.uk

@@ -0,0 +1,78 @@
+#  SPDX-License-Identifier: BSD-3-Clause
+#
+#  embedded-gcov Makefile.uk
+#
+#  Authors: Michalis Pappas <[email protected]>
+#
+#  Copyright (c) 2023, Unikraft GmbH
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions
+#  are met:
+#
+#  1. Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#  2. Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in the
+#     documentation and/or other materials provided with the distribution.
+#  3. Neither the name of the copyright holder nor the names of its
+#     contributors may be used to endorse or promote products derived from
+#     this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+#  POSSIBILITY OF SUCH DAMAGE.
+#
+################################################################################
+# App registration
+################################################################################
+$(eval $(call addlib,libembeddedgcov,$(CONFIG_LIBEMBEDDEDGCOV)))
+
+################################################################################
+# Sources
+################################################################################
+LIBEMBEDDEDGCOV_BRANCH = main
+LIBEMBEDDEDGCOV_URL = https://github.com/nasa-jpl/embedded-gcov.git
+LIBEMBEDDEDGCOV_PATCHDIR = $(LIBEMBEDDEDGCOV_BASE)/patches
+$(eval $(call clone,libembeddedgcov,$(LIBEMBEDDEDGCOV_URL),$(LIBEMBEDDEDGCOV_BRANCH)))
+$(eval $(call patch,libembeddedgcov,$(LIBEMBEDDEDGCOV_PATCHDIR),$(LIBEMBEDDEDGCOV_BASENAME)))
+
+################################################################################
+# Library sources
+################################################################################
+LIBEMBEDDEDGCOV_SRCS-y += $(LIBEMBEDDEDGCOV_ORIGIN)/code/gcov_public.c
+LIBEMBEDDEDGCOV_SRCS-y += $(LIBEMBEDDEDGCOV_ORIGIN)/code/gcov_gcc.c
+LIBEMBEDDEDGCOV_SRCS-y += $(LIBEMBEDDEDGCOV_ORIGIN)/code/gcov_printf.c
+
+################################################################################
+# Library includes
+################################################################################
+CINCLUDES-$(CONFIG_LIBEMBEDDEDGCOV) += -I$(LIBEMBEDDEDGCOV_ORIGIN)/code
+CXXINCLUDES-$(CONFIG_LIBEMBEDDEDGCOV) += -I$(LIBEMBEDDEDGCOV_ORIGIN)/code
+
+################################################################################
+# Library flags
+################################################################################
+
+CFLAGS-$(CONFIG_LIBEMBEDDEDGCOV) += -ftest-coverage -fprofile-arcs
+
+ifneq ($(CONFIG_LIBEMBEDDEDGCOV_OUTPUT_BINARY_FILE),)
+$(error Binary file output not implemented)
+endif
+ifneq ($(CONFIG_LIBEMBEDDEDGCOV_OUTPUT_BINARY_MEMORY),)
+$(error Memory output not implemented)
+endif
+
+LIBEMBEDDEDGCOV_CFLAGS-y                                                   += -Dgcov_printf=printf
+LIBEMBEDDEDGCOV_CFLAGS-$(CONFIG_LIBEMBEDDEDGCOV_OUTPUT_SERIAL_HEXDUMP)     += -DGCOV_OPT_OUTPUT_SERIAL_HEXDUMP
+LIBEMBEDDEDGCOV_CFLAGS-$(CONFIG_LIBEMBEDDEDGCOV_PRINT_STATUS)              += -DGCOV_OPT_PRINT_STATUS
+LIBEMBEDDEDGCOV_CFLAGS-$(CONFIG_LIBEMBEDDEDGCOV_PROVIDE_CALL_CONSTRUCTORS) += -DGCOV_OPT_PROVIDE_CALL_CONSTRUCTORS
+LIBEMBEDDEDGCOV_CFLAGS-$(CONFIG_LIBEMBEDDEDGCOV_USE_MALLOC)                += -DGCOV_OPT_USE_MALLOC

README.md

@@ -1,2 +1,64 @@
 # lib-embedded-gcov
-Coverage suppport
+
+Unikraft port of [embedded-gcov](https://github.com/nasa-jpl/embedded-gcov).
+
+## Step-by-step Instructions
+
+Here you can find step-by-step instructions on obtaining coverage information for a Unikraft application.
+
+For more information, see the documentation provided by [embedded-gcov](https://github.com/nasa-jpl/embedded-gcov).
+
+### Step 1: Prepare the application
+
+Initialization of gcov is done transparently to the application. `lib-embedded-gcov` adds the required GCC options for coverage, and at runtime, `__gcov_init()` is automatically called when Unikraft boots via constructors. Therefore no changes are required for initialization. However, if coverage collection must start at a later point, one can modify the application to call `gcov_clear_counters()` manually.
+
+On the other hand, it is necessary to modify the application to call `__gcov_exit()` manually. This function causes `lib-embedded-gcov` to gather and output coverage information using the selected output method.
+
+### Step 2: Select output method
+
+In the `embedded-gcov` section of Kconfig, select the output method to use:
+- `Console`: Writes coverage data to console output.
+- `File`: Writes coverage data to a binary file.
+- `Memory`: Writes coverage data into memory.
+
+### Step 3: Run the application
+
+**Console output:**
+On QEMU, you can obtain the console output by passing the `logfile` parameter to the character device that implements the serial output:
+```
+ -chardev stdio,id=char0,logfile=serial.log,signal=off -serial chardev:char0
+```
+*NOTE*: It is essential not to use `-nographic` option here because that clashes with the redirection of standard output.
+
+This QEMU run will dump console output into a text file named `serial.log`.
+
+### Step 4: Generate coverage report
+
+You must process the output to obtain coverage results in a pleasant viewing fashion. `lib-embedded-gcov` provides the `gcov_process.sh` script for that, which is essentially a wrapper around the tools provided by `embedded-gcov`.
+
+Before executing the script below make sure you have the required dependencies installed, that is:
+- `dox2unix`
+- `lcov`
+
+With the dependencies installed, invoke `gcov_process.sh` with parameters depending on the output method selected.
+
+**Console output:**
+```bash
+lib-embedded-gcov/scripts/gcov_process.sh -c <console_output> <build_directory>
+```
+
+**Binary file / Memory output:**
+```bash
+lib-embedded-gcov/scripts/gcov_process.sh -b <binary_output> <build_directory>
+```
+
+`gcov_process.sh` will generate a lcov report and provide a link, as shown below:
+```
+...
+Writing directory view page.
+Overall coverage rate:
+  lines......: 29.8% (2345 of 7858 lines)
+  functions..: 36.3% (228 of 628 functions)
+
+lcov report in file:///tmp/uk_embedded-gcov/app-helloworld/build/libembeddedgcov/origin/results/html/index.html
+```

patches/0001-Disable-all-user-options-to-allow-controlling-via-KC.patch

@@ -0,0 +1,61 @@
+From 51043fb1ad5b99a66749bce2661b388e26b6f90f Mon Sep 17 00:00:00 2001
+From: michpappas <[email protected]>
+Date: Sat, 21 Jan 2023 18:11:26 +0100
+Subject: [PATCH] Disable all user options to allow controlling via KConfig
+
+---
+ code/gcov_public.h | 10 +++++-----
+ 1 file changed, 5 insertions(+), 5 deletions(-)
+
+diff --git a/code/gcov_public.h b/code/gcov_public.h
+index 0982c2c..9a32a8c 100644
+--- a/code/gcov_public.h
++++ b/code/gcov_public.h
+@@ -51,7 +51,7 @@
+  * If defined, you must also provide defs below
+  * for GCOV_PRINT_STR and GCOV_PRINT_NUM.
+  */
+-#define GCOV_OPT_PRINT_STATUS
++//#define GCOV_OPT_PRINT_STATUS
+
+ /* Reset watchdog timeout during gcov tree scanning.
+  * Might be needed if you enable serial output on a slow port,
+@@ -95,7 +95,7 @@ extern void *__ctor_end;
+  * You might NOT want this if you are extremely memory constrained
+  * (such as in PROM) and do not need this function to take up some bytes.
+  */
+-#define GCOV_OPT_PROVIDE_CLEAR_COUNTERS
++//#define GCOV_OPT_PROVIDE_CLEAR_COUNTERS
+
+ /* Provide small imitation printf function.
+  * This is only needed if you want serial port outputs and
+@@ -104,7 +104,7 @@ extern void *__ctor_end;
+  * write_bytes() that does the actual serial output in your system.
+  * See gcov_printf.c
+  */
+-#define GCOV_OPT_PROVIDE_PRINTF_IMITATION
++//#define GCOV_OPT_PROVIDE_PRINTF_IMITATION
+
+ /* select data output method(s) ------------------------------------ */
+
+@@ -122,7 +122,7 @@ extern void *__ctor_end;
+
+ /* Modify this output filename if desired */
+ /* Not used if you do not define GCOV_OPT_OUTPUT_BINARY_FILE */
+-#define GCOV_OUTPUT_BINARY_FILENAME "gcov_output.bin"
++//#define GCOV_OUTPUT_BINARY_FILENAME "gcov_output.bin"
+
+ /* Modify file headers, data type and functions, if needed */
+ /* Not used if you do not define GCOV_OPT_OUTPUT_BINARY_FILE */
+@@ -164,7 +164,7 @@ typedef FILE * GCOV_FILE_TYPE;
+  * for GCOV_PRINT_STR and GCOV_PRINT_NUM.
+  * Can be combined with other GCOV_OPT_OUTPUT_* options.
+  */
+-#define GCOV_OPT_OUTPUT_SERIAL_HEXDUMP
++//#define GCOV_OPT_OUTPUT_SERIAL_HEXDUMP
+
+ /* Function to print a string without newline.
+  * Not used if you don't define either GCOV_OPT_PRINT_STATUS
+-- 
+2.25.1
+

patches/0002-Use-consistent-types.patch

@@ -0,0 +1,29 @@
+From a3e60bce495397005c093a2a905b65e0baabdbee Mon Sep 17 00:00:00 2001
+From: Michalis Pappas <[email protected]>
+Date: Mon, 8 May 2023 09:08:09 +0200
+Subject: [PATCH] Use consistent types
+
+Replace UINT32 in the function declaration of __gcov_call_constructors
+with u32 which is used in the rest of the codebase.
+
+Signed-off-by: Michalis Pappas <[email protected]>
+---
+ code/gcov_public.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/code/gcov_public.c b/code/gcov_public.c
+index 94aaff4..98e6fc5 100644
+--- a/code/gcov_public.c
++++ b/code/gcov_public.c
+@@ -203,7 +203,7 @@ void __gcov_call_constructors(void) {
+     while (ctor != &__ctor_end) {
+         void (*func)(void);
+
+-        func = (void ( *)(void))(*(UINT32 *)ctor);
++        func = (void ( *)(void))(*(u32 *)ctor);
+
+         func();
+         ctor++;
+-- 
+2.34.1
+

scripts/gcov_process.sh

@@ -0,0 +1,39 @@
+#!/bin/bash
+set -e
+
+if [[ $# -ne 2 ]]; then
+	echo "Usage: $0 <build_dir> <console_dump>"
+	exit
+fi
+
+if [ -n "${CROSS_COMPILE}" ]; then
+	GCOV=${CROSS_COMPILE}/gcov
+else
+	GCOV=$(which gcov)
+fi
+
+if [ -z "$GCOV" ]; then
+	echo "$0: Could not find gcov"
+	exit
+fi
+
+BUILD_DIR=$(realpath $1)
+CONSOLE_DUMP=$(realpath $2)
+GCOV_DIR=${BUILD_DIR}/libembeddedgcov/origin/
+
+cd ${GCOV_DIR}/scripts
+
+rm -rf ../objs/*
+rm -rf ../results/*
+
+find $BUILD_DIR -type d -name objs -prune -o -name \*.gcno -exec cp {} ../objs/ \;
+
+lcov --gcov-tool ${CROSS_COMPILE}gcov --capture --initial \
+     --directory ../objs/ -o ../results/baseline.info
+
+./gcov_convert.sh $CONSOLE_DUMP
+./lcov_newcoverage.sh
+./lcov_combine_new_base.sh
+./genhtml_report.sh
+
+echo -e "\nlcov report in file://$(realpath ../results/html)/index.html\n"