build_tools/third_party/libbacktrace/BUILD.bazel

# Copyright 2025 The IREE Authors
#
# Licensed under the Apache License v2.0 with LLVM Exceptions.
# See https://llvm.org/LICENSE.txt for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

load("//build_tools/bazel:build_defs.oss.bzl", "iree_cmake_extra_content", "iree_runtime_cc_library")

package(default_visibility = ["//visibility:public"])

# CMake builds libbacktrace via FetchContent.
# This file is only used for Bazel builds.
iree_cmake_extra_content(
    content = """
# libbacktrace is built by build_tools/third_party/libbacktrace/CMakeLists.txt
# using FetchContent. This file is only used for Bazel builds.
return()
""",
    inline = True,
)

# Linux implementation with libbacktrace from BCR.
# Includes pthreads since libbacktrace usage requires pthread_once.
# Includes dl since status_stack_trace.c uses dladdr (needed on glibc < 2.34).
# The hdrs exports our wrapper header which re-exports BCR's backtrace.h,
# allowing the layering check to see the header dependency chain.
# We use includes=["."] to make the wrapper includable as <iree_libbacktrace.h>.
iree_runtime_cc_library(
    name = "libbacktrace_linux",
    hdrs = ["iree_libbacktrace.h"],
    defines = ["IREE_HAVE_LIBBACKTRACE=1"],
    includes = ["."],
    deps = [
        "//build_tools:dl",
        "//build_tools:pthreads",
        "@libbacktrace//:libbacktrace",
    ],
)

# Empty target for non-Linux platforms.
iree_runtime_cc_library(
    name = "libbacktrace_disabled",
)

# Transparent alias that switches between implementations.
# Using alias (not cc_library wrapper) properly propagates headers for layering check.
alias(
    name = "libbacktrace",
    actual = select({
        "@platforms//os:linux": ":libbacktrace_linux",
        "//conditions:default": ":libbacktrace_disabled",
    }),
)