W-M-R commented on code in PR #21344:
URL: https://github.com/apache/nuttx/pull/21344#discussion_r4477516653
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tools/gcov.py:
##########
@@ -18,33 +18,352 @@
# License for the specific language governing permissions and limitations
# under the License.
+"""Code coverage report generator for NuttX.
+
+Supports both GCC gcov and Clang source-based coverage. The toolchain is
+inferred from the ELF binary's `.comment` section, and the cross-compile
+prefix (if any) is inferred from the ELF machine type, so users no longer
+have to specify `-t`/`--toolchain`.
+
+Both toolchains converge on the lcov tracefile format: gcc captures it
+with `lcov -c`, clang exports it with `llvm-cov export -format=lcov`, and
+`genhtml` renders both, so reports look the same regardless of the
+toolchain and tracefiles can be merged with `lcov --add-tracefile`.
+
+Usage example:
+
+ gcov.py -e build/nuttx -s build -a coverage_data.bin -o report_dir
+
+The required tools (gcov/lcov/genhtml for GCC; llvm-profdata/llvm-cov/
+llvm-readelf/ld.lld for Clang) are resolved from PATH; the cross-compile
+gcov is matched by arch (e.g. aarch64-none-elf-gcov for EM_AARCH64).
+
+Use `-b OLD=NEW` (repeatable) to rewrite source paths recorded by the
+compiler at build time to local paths, mirroring `-fdebug-prefix-map`:
+
+ gcov.py -b /old/build/path=/new/local/path ...
+
+When only the local root is known, pass just NEW and the build-time root
+is inferred from the paths recorded in the coverage data:
+
+ gcov.py -b /new/local/path ...
+"""
+
import argparse
+import concurrent.futures
+import json
import os
import re
import shutil
+import struct
import subprocess
import sys
+from dataclasses import dataclass, field
+from typing import List, Optional, Tuple
+
+# =============================================================================
+# 1. CONSTANTS
+# =============================================================================
+
+# LLVM raw profile magic bytes (first 8 bytes of .profraw).
+#
+# The magic is a uint64_t written by the runtime in native byte order
+# (high byte 0xff, low byte 0x81; "lprofr"/"lprofR" in the middle), so
+# big-endian platforms produce \xff..\x81 and little-endian platforms
+# (ARM aarch64, x86_64, etc.) produce \x81..\xff. Both forms must be
+# accepted, mirroring LLVM's RawInstrProfReader::hasFormat which compares
+# the on-disk magic against both the native and byte-swapped values.
+#
+# 64-bit BE: \xff lprofr \x81 / 64-bit LE: \x81 rforpl \xff
+# 32-bit BE: \xff lprofR \x81 / 32-bit LE: \x81 Rforpl \xff
+PROFRAW_MAGIC_64 = b"\xff\x6c\x70\x72\x6f\x66\x72\x81"
+PROFRAW_MAGIC_32 = b"\xff\x6c\x70\x72\x6f\x66\x52\x81"
+PROFRAW_MAGICS = (
+ PROFRAW_MAGIC_64,
+ PROFRAW_MAGIC_64[::-1],
+ PROFRAW_MAGIC_32,
+ PROFRAW_MAGIC_32[::-1],
+)
+
+# gcov binary pack heuristic:
+# First 4 bytes are path_len (LE uint32), typically 30~200 for gcda paths.
+# Followed by a path string starting with a printable char (not \x00 or \xff).
+GCOV_BINPACK_PATH_LEN_MIN = 10
+GCOV_BINPACK_PATH_LEN_MAX = 4096
+
+# Suffix appended to a -a input file to name the directory holding the
+# coverage data extracted from it (hex dump / binpack -> individual files).
+CONVERT_SUFFIX = "_convert"
+
+# ELF e_machine values we care about for cross-prefix inference.
+EM_386 = 3
+EM_X86_64 = 62
+EM_ARM = 40
+EM_AARCH64 = 183
+EM_RISCV = 243
+EM_XTENSA = 94
+EM_TRICORE = 44
+
+# Candidate cross-compile gcov binary names per architecture, in priority
+# order. The first one found on PATH is used.
+GCC_CROSS_PREFIXES = {
+ EM_AARCH64: ["aarch64-none-elf-gcov", "aarch64-linux-gnu-gcov"],
+ EM_ARM: ["arm-none-eabi-gcov", "arm-linux-gnueabi-gcov"],
+ EM_RISCV: ["riscv64-unknown-elf-gcov", "riscv32-unknown-elf-gcov"],
Review Comment:
Other architectures have not been tested before, and will be integrated
after testing
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