# Copyright 2017 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import("//build/config/clang/clang.gni")
import("//build/config/sanitizers/sanitizer_default_options.gni")
import("//build/toolchain/variant.gni")

variant("asan") {
  common_flags = [ "-fsanitize=address" ]
  cflags = [
    # See https://fxbug.dev/66129 and
    # https://github.com/google/sanitizers/issues/1017.
    "-mllvm",
    "-asan-use-private-alias=1",
  ]

  # TODO(phosek): use runtime.json instead of invoking Clang.
  if (is_fuchsia) {
    extension = ".so"
  } else if (is_mac) {
    extension = "_osx_dynamic.dylib"
  } else {
    extension = ".a"
  }

  # For dynamic linking (Fuchsia and macOS), there is just one combined DSO.
  # For static linking (other platforms), there are separate libraries for the
  # generic (C) and C++-specific runtime support.
  needed_asan_libs = [ "asan" ]
  if (extension == ".a") {
    needed_asan_libs += [ "asan_cxx" ]
  }
  rustflags = []
  foreach(asan, needed_asan_libs) {
    libclang_rt_asan = rebase_path(
            exec_script("/usr/bin/env",
                        [
                          "${rebased_clang_prefix}/clang",
                          "--target=${current_target_tuple}",
                          "-print-file-name=libclang_rt.${asan}${extension}",
                        ],
                        "trim string"),
            root_build_dir)
    rustflags += [ "-Clink-arg=${libclang_rt_asan}" ]
  }
  if (is_fuchsia) {
    rustflags += [ "-Clink-arg=-dynamic-linker=asan/ld.so.1" ]
  }

  # ASan wants frame pointers because it captures stack traces
  # on allocations and such, not just on errors.
  configs = [ "//build/config:frame_pointers" ]

  if (is_kernel) {
    configs += [ "//zircon/kernel/lib/instrumentation/asan:kasan" ]
  }

  deps = [ ":asan_default_options" ]

  # Expose the presence of sanitizers as a compile-time condition.
  # This allows conditional compilation of code for this variant,
  # for instance in order to disable a specific test case.
  # TODO(fxbug.dev/87239): use cfg_sanitize instead.
  rustflags += [ "--cfg=feature=\"variant_asan\"" ]
}

sanitizer_default_options("asan_default_options") {
  # The asan runtime includes the lsan and ubsan runtimes, which parse their
  # own options.
  deps = [
    ":lsan_default_options",
    ":ubsan_default_options",
  ]
}

sanitizer_default_options("lsan_default_options") {
}

# TODO(fxbug.dev/45047): Temporary while leaks are plugged.
# As leak bugs are found, file a bug #nnnnn for the leaky test/component,
# and then add:
# ```
#   # TODO(nnnnn): Fix the leaks and remove this.
#   deps += [ "//build/config/sanitizers:suppress-lsan.DO-NOT-USE-THIS" ]
# ```
# to the target that builds the leaky code.  When all leaky tests have been
# marked that way, the asan_default_options default above will be removed.
#
# To trim this allowlist:
# scripts/gn/trim_visibility.py --target="//build/config/sanitizers:suppress-lsan.DO-NOT-USE-THIS"
sanitizer_extra_options("suppress-lsan.DO-NOT-USE-THIS") {
  visibility = [
    "//src/cobalt/bin/system-metrics/*",
    "//src/developer/shell/josh/*",
    "//src/devices/usb/drivers/xhci/*",
    "//src/fonts/*",
    "//src/graphics/lib/compute/*",
    "//src/graphics/lib/compute/forma/*",
    "//src/graphics/lib/compute/surpass/*",
    "//src/lib/scoped_task/*",
    "//src/media/audio/drivers/intel-hda/controller/*",
    "//src/settings/*",
    "//third_party/alacritty/alacritty_terminal/*",
    "//third_party/crashpad/*",
    "//zircon/third_party/uapp/dash/*",
  ]

  args = [ "detect_leaks=0" ]
  output_name = "lsan_default_options"
  tags = [ "lsan" ]
}

sanitizer_extra_options("suppress-asan-stack-use-after-return") {
  visibility = [
    # These tests need to check actual stack behavior, not fake stack.
    "//zircon/system/ulib/c/test/sanitizer:memory-snapshot-test",
  ]

  args = [ "detect_stack_use_after_return=0" ]
  output_name = "asan_default_options"
  tags = [ "asan" ]
}

# Disable the container overflow detection, which will create false positives
# if a part of the application is built with asan and another part is not. See
# https://github.com/google/sanitizers/wiki/AddressSanitizerContainerOverflow.
sanitizer_extra_options("suppress-asan-container-overflow") {
  visibility = [ "//src/lib/llvm:*" ]

  args = [ "detect_container_overflow=0" ]
  output_name = "asan_default_options"
  tags = [ "asan" ]
}

config("suppress-tsan.DO-NOT-USE-THIS") {
  cflags = [ "-fno-sanitize=thread" ]
  visibility = []
}

config("suppress-ubsan.DO-NOT-USE-THIS") {
  cflags = [ "-fno-sanitize=undefined" ]
  visibility = [
    "//build/config:temporarily_disable_ubsan_do_not_use",
    "//zircon/third_party/uapp/dash/*",
  ]
}

config("no-shadow-call-stack") {
  if (current_cpu == "arm64" && !is_gcc) {
    cflags = [ "-fno-sanitize=shadow-call-stack" ]
  }
}

config("no_sanitizers") {
  cflags = [ "-fno-sanitize=all" ]
  if (!is_gcc) {
    cflags += [ "-fsanitize-coverage=0" ]
  }
  configs = [ "//build/config:no_stack_protector" ]
}

# rustc flags for AddressSanitizer, primarily used for fuzzing Rust code.
# TODO(fxbug.dev/45102): This is technically wrong; it will use clang's ASan.
# rustc is built from a different fork of LLVM and should use a matching ASan.
# However, Fuchsia's libc and dynamic linker cooperate to set up the shadow
# memory and currently always link against clang's ASan. Using both rustc and
# clang's ASan would also be infeasible, as symbol names and shadow memory
# regions would conflict.
#
# Thus, variants using this config currently IGNORE the potential ABI
# incompatibility and simply use clang's ASan. If/when this breaks, these
# test-only variants should be disabled until a resolution can be found.
#
# Additionally, variants using this config CANNOT be used on binaries linked
# by rustc, as it will fail to find its runtime. It CAN be used to build
# libraries with rustc that are then linked into executables by clang, e.g.
# fuzzers.
variant("rust-asan") {
  rustflags = [ "-Zsanitizer=address" ]
}

# TODO(fxbug.dev/43710): Building with this variant alone can still lead to
# some build errors, but this is still needed for lsan tests (see
# //zircon/system/ulib/c/test/sanitizer:lsan-test).
variant("lsan") {
  ldflags = [ "-fsanitize=leak" ]

  # LSan wants frame pointers because it captures stack traces
  # on allocations and such, not just on errors.
  configs = [ "//build/config:frame_pointers" ]

  if (is_fuchsia) {
    # The LSan runtime is statically linked but depends on libzircon.
    libs = [ "zircon" ]
  }

  deps = [ ":lsan_default_options" ]
}

variant("ubsan") {
  common_flags = [ "-fsanitize=undefined" ]

  if (is_fuchsia) {
    dynamic_linker_flags =
        "-dynamic-linker=${toolchain_variant.libprefix}ld.so.1"
    ldflags = [ "-Wl,$dynamic_linker_flags" ]
    rustflags = [ "-Clink-arg=$dynamic_linker_flags" ]
  }

  if (is_host) {
    # TODO(fxbug.dev/60446): remove this once LLVM prebuilts have variants
    # Disable vptr checks on host binaries.
    # This is a temporary hack around the facts that:
    # 1) UBSan's vptr check requires RTTI, and mixing RTTI and no-RTTI TUs in
    #    the same binary leads to spurious UBSan failures
    # 2) we have non-variant prebuilts for LLVM, which lack RTTI
    # 3) we have binaries that depend on both these LLVM prebuilts and other libraries
    # Disabling this check on host tools for now allows us to enable UBSan on
    # host tools, which is a net win.
    common_flags += [ "-fno-sanitize=vptr" ]
  }

  # If asan is also in use, it handles ubsan_default_options indirectly.
  if (toolchain_variant.tags + [ "asan" ] - [ "asan" ] ==
      toolchain_variant.tags) {
    deps = [ ":ubsan_default_options" ]
  }
}

sanitizer_default_options("ubsan_default_options") {
}

variant("sancov") {
  common_flags = [ "-fsanitize-coverage=trace-pc-guard" ]
}

variant("tsan") {
  common_flags = [ "-fsanitize=thread" ]

  # TODO(phosek): use runtime.json instead of invoking Clang.
  if (is_mac) {
    extension = "_osx_dynamic.dylib"
  } else {
    extension = ".a"
  }

  # For dynamic linking (macOS), there is just one combined DSO.
  # For static linking (other platforms), there are separate libraries for the
  # generic (C) and C++-specific runtime support.
  needed_tsan_libs = [ "tsan" ]
  if (extension == ".a") {
    needed_tsan_libs += [ "tsan_cxx" ]
  }
  rustflags = []
  foreach(tsan, needed_tsan_libs) {
    libclang_rt_tsan = rebase_path(
            exec_script("/usr/bin/env",
                        [
                          "${rebased_clang_prefix}/clang",
                          "--target=${current_target_tuple}",
                          "-print-file-name=libclang_rt.${tsan}${extension}",
                        ],
                        "trim string"),
            root_build_dir)
    rustflags += [ "-Clink-arg=${libclang_rt_tsan}" ]
  }

  deps = [ ":tsan_default_options" ]

  # Expose the presence of sanitizers as a compile-time condition.
  # This allows conditional compilation of code for this variant,
  # for instance in order to disable a specific test case.
  # TODO(fxbug.dev/87239): use cfg_sanitize instead.
  rustflags += [ "--cfg=feature=\"variant_tsan\"" ]
}

sanitizer_default_options("tsan_default_options") {
}

variant("hwasan") {
  common_flags = [ "-fsanitize=hwaddress" ]

  cflags = [
    # TODO(fxbug.dev/57112): Temporarily disable instrumenting globals for now.
    # Tagging on globals affects taking offsets of vtables in the relative-
    # vtables ABI and results in a linker error. Once we finalize how we want
    # to handle this case, we should come back and re-enable global
    # instrumentation.
    "-mllvm",
    "-hwasan-globals=0",
  ]

  # TODO(phosek): use runtime.json instead of invoking Clang.
  if (is_fuchsia) {
    extension = ".so"
  } else {
    extension = ".a"
  }

  # For dynamic linking (Fuchsia and macOS), there is just one combined DSO.
  # For static linking (other platforms), there are separate libraries for the
  # generic (C) and C++-specific runtime support.
  needed_hwasan_libs = [ "hwasan" ]
  if (extension == ".a") {
    needed_hwasan_libs += [ "hwasan_cxx" ]
  }
  rustflags = []
  foreach(hwasan, needed_hwasan_libs) {
    libclang_rt_hwasan = rebase_path(
            exec_script("/usr/bin/env",
                        [
                          "${rebased_clang_prefix}/clang",
                          "--target=${current_target_tuple}",
                          "-print-file-name=libclang_rt.${hwasan}${extension}",
                        ],
                        "trim string"),
            root_build_dir)
    rustflags += [ "-Clink-arg=${libclang_rt_hwasan}" ]
  }
  if (is_fuchsia) {
    rustflags += [ "-Clink-arg=-dynamic-linker=hwasan/ld.so.1" ]
  }

  deps = [ ":hwasan_default_options" ]

  # Expose the presence of sanitizers as a compile-time condition.
  # This allows conditional compilation of code for this variant,
  # for instance in order to disable a specific test case.
  # TODO(fxbug.dev/87239): use cfg_sanitize instead.
  rustflags += [ "--cfg=feature=\"variant_hwasan\"" ]
}

sanitizer_default_options("hwasan_default_options") {
}