gcov: Support for the most streamlined profile of LLVM-embedded-toolc…

…hain-for-Arm

1. Excerpted from: https://github.com/ARM-software/LLVM-embedded-toolchain-for-Arm/blob/main/samples/src/cpp-baremetal-semihosting-prof/proflib.c
2. Since llvm profile supports more than just gcov, and some features have not yet been explored, two clang gcov implementations are supported after this patch
3. Using this lib only supports the gcov compilation options of "-fprofile-instr-generate -fcoverage-mapping"
4. This file is heavily dependent on the compiler clang version, and is currently aligned with ci, supporting 17.0.1 and below. 18 and above are not supported by this library due to different internal implementations of the compiler

Signed-off-by: wangmingrong1 <[email protected]>

libs/libc/Kconfig

@@ -14,6 +14,7 @@ source "libs/libc/string/Kconfig"
 source "libs/libc/pthread/Kconfig"
 source "libs/libc/dlfcn/Kconfig"
 source "libs/libc/modlib/Kconfig"
+source "libs/libc/gcov/Kconfig"
 source "libs/libc/gdbstub/Kconfig"
 source "libs/libc/grp/Kconfig"
 source "libs/libc/pwd/Kconfig"

libs/libc/Makefile

@@ -32,6 +32,7 @@ include dlfcn/Make.defs
 include errno/Make.defs
 include eventfd/Make.defs
 include fixedmath/Make.defs
+include gcov/Make.defs
 include gdbstub/Make.defs
 include grp/Make.defs
 include gnssutils/Make.defs

libs/libc/gcov/CMakeLists.txt

@@ -0,0 +1,27 @@
+# ##############################################################################
+# libs/libc/gcov/CMakeLists.txt
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more contributor
+# license agreements.  See the NOTICE file distributed with this work for
+# additional information regarding copyright ownership.  The ASF licenses this
+# file to you under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License.  You may obtain a copy of
+# the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations under
+# the License.
+#
+# ##############################################################################
+
+if(CONFIG_LIB_GCOV)
+  if(CONFIG_ARCH_TOOLCHAIN_CLANG)
+    target_sources(c PRIVATE lib_clang.c)
+  endif()
+endif()

libs/libc/gcov/Kconfig

@@ -0,0 +1,16 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+config LIB_GCOV
+	tristate "Enable GCOV support"
+	select HAVE_CXXINITIALIZE
+	default n
+	---help---
+		Enable GCOV support for code coverage analysis.
+		After turning on this option, code coverage can be analyzed.
+		If this option is enabled, image size and performance will be
+		significantly reduced. Before use, you need to add the
+		"-fprofile-instr-generate -fcoverage-mapping" compilation parameters
+		to the file to be analyzed.

libs/libc/gcov/Make.defs

@@ -0,0 +1,34 @@
+############################################################################
+# libs/libc/gcov/Make.defs
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+############################################################################
+
+# Add the fixed precision math C files to the build
+
+ifeq ($(CONFIG_LIB_GCOV),y)
+	ifeq ($(CONFIG_ARCH_TOOLCHAIN_CLANG),y)
+		CSRCS += lib_clang.c
+	endif
+endif
+
+# Add the fixed precision math directory to the build
+
+DEPPATH += --dep-path gcov
+VPATH += :gcov

libs/libc/gcov/lib_clang.c

@@ -0,0 +1,294 @@
+/****************************************************************************
+ * libs/libc/gcov/lib_clang.c
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <inttypes.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define INSTR_PROF_RAW_VERSION 8
+#define INSTR_PROF_RAW_VERSION_VAR __llvm_profile_raw_version
+#define INSTR_PROF_PROFILE_RUNTIME_VAR __llvm_profile_runtime
+
+/* Magic number to detect file format and endianness.
+ * Use 255 at one end, since no UTF-8 file can use that character.  Avoid 0,
+ * so that utilities, like strings, don't grab it as a string.  129 is also
+ * invalid UTF-8, and high enough to be interesting.
+ * Use "lprofr" in the centre to stand for "LLVM Profile Raw", or "lprofR"
+ * for 32-bit platforms.
+ */
+
+#define INSTR_PROF_RAW_MAGIC_64                                                \
+  (uint64_t)255 << 56 | (uint64_t)'l' << 48 | (uint64_t)'p' << 40 |            \
+      (uint64_t)'r' << 32 | (uint64_t)'o' << 24 | (uint64_t)'f' << 16 |        \
+      (uint64_t)'r' << 8 | (uint64_t)129
+
+#define INSTR_PROF_RAW_MAGIC_32                                                \
+  (uint64_t)255 << 56 | (uint64_t)'l' << 48 | (uint64_t)'p' << 40 |            \
+      (uint64_t)'r' << 32 | (uint64_t)'o' << 24 | (uint64_t)'f' << 16 |        \
+      (uint64_t)'R' << 8 | (uint64_t)129
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+enum value_kind
+{
+  IPVK_INDIRECT_CALL_TARGET = 0,
+  IPVK_MEM_OP_SIZE = 1,
+  IPVK_FIRST = IPVK_INDIRECT_CALL_TARGET,
+  IPVK_LAST = IPVK_MEM_OP_SIZE,
+};
+
+typedef struct __attribute__((aligned(8))) __llvm_profile_data
+{
+  const uint64_t name_ref;
+  const uint64_t func_hash;
+  const intptr_t counter_ptr;
+  const intptr_t func_ptr;
+  intptr_t       values;
+  const uint32_t num_counters;
+  const uint16_t num_value_sites[IPVK_LAST + 1];
+}__llvm_profile_data;
+
+typedef struct __llvm_profile_header
+{
+  uint64_t magic;
+  uint64_t version;
+  uint64_t binary_ids_size;
+  uint64_t data_size;
+  uint64_t padding_bytes_before_counters;
+  uint64_t counters_size;
+  uint64_t padding_bytes_after_counters;
+  uint64_t names_size;
+  uint64_t counters_delta;
+  uint64_t names_delta;
+  enum value_kind value_kind_last;
+}__llvm_profile_header;
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static uint64_t INSTR_PROF_RAW_VERSION_VAR = INSTR_PROF_RAW_VERSION;
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/* Record where the data is in memory. Within each of the types of data,
+ * it's stored consecutively.
+ */
+
+extern char __start__llvm_prf_names[];
+extern char __end__llvm_prf_names[];
+extern char __start__llvm_prf_data[];
+extern char __end__llvm_prf_data[];
+extern char __start__llvm_prf_cnts[];
+extern char __end__llvm_prf_cnts[];
+
+int INSTR_PROF_PROFILE_RUNTIME_VAR;
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static size_t __llvm_profile_counter_entry_size(void)
+{
+  return sizeof(uint64_t);
+}
+
+static uint64_t __llvm_profile_get_magic(void)
+{
+  return sizeof(void *) == sizeof(uint64_t) ? (INSTR_PROF_RAW_MAGIC_64)
+                                            : (INSTR_PROF_RAW_MAGIC_32);
+}
+
+static uint64_t __llvm_profile_get_version(void)
+{
+  return __llvm_profile_raw_version;
+}
+
+static uint64_t __llvm_profile_get_num_counters(const char *begin,
+                                                const char *end)
+{
+  return (((intptr_t)end + __llvm_profile_counter_entry_size() - 1) -
+          (intptr_t)begin) / __llvm_profile_counter_entry_size();
+}
+
+static int __llvm_write_binary_ids(void)
+{
+  return 0;
+}
+
+static const __llvm_profile_data *__llvm_profile_begin_data(void)
+{
+  return &__start__llvm_prf_data;
+}
+
+static const __llvm_profile_data *__llvm_profile_end_data(void)
+{
+  return &__end__llvm_prf_data;
+}
+
+static const char *__llvm_profile_begin_names(void)
+{
+  return &__start__llvm_prf_names;
+}
+
+static const char *__llvm_profile_end_names(void)
+{
+  return &__end__llvm_prf_names;
+}
+
+static char *__llvm_profile_begin_counters(void)
+{
+  return &__start__llvm_prf_cnts;
+}
+
+static char *__llvm_profile_end_counters(void)
+{
+  return &__end__llvm_prf_cnts;
+}
+
+static uint64_t __llvm_profile_get_num_padding_bytes(uint64_t size)
+{
+  return 7 & (sizeof(uint64_t) - size % sizeof(uint64_t));
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+uint64_t __llvm_profile_get_num_data(const __llvm_profile_data *begin,
+                                     const __llvm_profile_data *end)
+{
+  return (((intptr_t)end + sizeof(__llvm_profile_data) - 1) -
+          (intptr_t)begin) / sizeof(__llvm_profile_data);
+}
+
+/* Given a pointer to the __llvm_profile_data for the function, record the
+ * bounds of the profile data and profile count sections.
+ * This function is called several time by the __llvm_profile_init function
+ * at program start.
+ *
+ * If this function is called we register __llvm_profile_dump() with
+ * atexit to write out the profile information to file.
+ */
+
+void __llvm_profile_register_function(void *data_)
+{
+  (void)data_;
+}
+
+void __llvm_profile_register_names_function(void *names_start,
+                                       uint64_t names_size)
+{
+  (void)names_start;
+  (void)names_size;
+}
+
+/* Called by an atexit handler. Writes a file called default.profraw
+ * containing the profile data. This needs to be merged by
+ * llvm-prof. See the clang profiling documentation for details.
+ */
+
+void __llvm_profile_dump(const char *path)
+{
+  FILE *fd;
+
+  /* Header: __llvm_profile_header from InstrProfData.inc */
+
+  const char *filename = path;
+
+  /* Calculate size of sections. */
+
+  const __llvm_profile_data *data_begin = __llvm_profile_begin_data();
+  const __llvm_profile_data *data_end = __llvm_profile_end_data();
+  const uint64_t num_data =
+    __llvm_profile_get_num_data(data_begin, data_end);
+
+  const char *counters_begin = __llvm_profile_begin_counters();
+  const char *counters_end = __llvm_profile_end_counters();
+  const uint64_t num_counters =
+    __llvm_profile_get_num_counters(counters_begin, counters_end);
+
+  const char *names_begin = __llvm_profile_begin_names();
+  const char *names_end = __llvm_profile_end_names();
+  const uint64_t names_size = (names_end - names_begin) * sizeof(char);
+
+  uint64_t padding_bytes_after_names =
+    __llvm_profile_get_num_padding_bytes(names_size);
+
+  __llvm_profile_header hdr;
+  hdr.magic = __llvm_profile_get_magic();
+  hdr.version = __llvm_profile_get_version();
+  hdr.binary_ids_size = __llvm_write_binary_ids();
+  hdr.data_size = num_data;
+  hdr.padding_bytes_before_counters = 0;
+  hdr.counters_size = num_counters;
+  hdr.padding_bytes_after_counters = 0;
+  hdr.names_size = names_size;
+  hdr.counters_delta = (uintptr_t)counters_begin - (uintptr_t)data_begin;
+  hdr.names_delta = (uintptr_t)names_begin;
+  hdr.value_kind_last = IPVK_LAST;
+
+  fd = fopen(filename, "wb");
+  if (!fd)
+    {
+      perror("fopen default.profraw failed");
+      return;
+    }
+
+  /* Header */
+
+  fwrite(&hdr, sizeof(hdr), 1, fd);
+
+  /* Data */
+
+  fwrite(data_begin, sizeof(__llvm_profile_data), num_data, fd);
+
+  /* Counters */
+
+  fwrite(counters_begin, sizeof(uint64_t), num_counters, fd);
+
+  /* Names */
+
+  fwrite(names_begin, sizeof(uint8_t), names_size, fd);
+
+  /* Padding */
+
+  for (; padding_bytes_after_names != 0; --padding_bytes_after_names)
+    {
+      fputc(0, fd);
+    }
+
+  fclose(fd);
+}