tor-browser

memory.configure (5620B)

---

# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
# vim: set filetype=python:
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.


@depends(target, js_package)
def jemalloc_default(target, js_package):
    if js_package:
        return False
    return target.kernel in ("Darwin", "Linux", "WINNT")


# mozjemalloc doesn't work with these sanitisers, it mostly-works with ubsan
# (so we leave that enabled) except for loading the configuration from the
# environment, it will fall-back to default settings.
imply_option("--enable-jemalloc", False, when=asan | msan | tsan)

option(
    "--enable-jemalloc",
    env="MOZ_MEMORY",
    default=jemalloc_default,
    help="{Replace|Do not replace} memory allocator with jemalloc",
)


set_config("MOZ_MEMORY", True, when="--enable-jemalloc")
set_define("MOZ_MEMORY", True, when="--enable-jemalloc")


@depends("--enable-jemalloc", moz_debug, win32_redist_dir)
def check_redist(jemalloc, debug, win32_redist_dir):
    if not jemalloc and not win32_redist_dir and not debug:
        log.warning(
            "When not building jemalloc, you need to build with --with-redist or set WIN32_REDIST_DIR."
        )


@depends(milestone, build_project)
def replace_malloc_default(milestone, build_project):
    if build_project == "memory":
        return True
    if milestone.is_early_beta_or_earlier and build_project != "js":
        return True


option(
    "--enable-replace-malloc",
    default=replace_malloc_default,
    when="--enable-jemalloc",
    help="{Enable|Disable} ability to dynamically replace the malloc implementation",
)


set_config("MOZ_REPLACE_MALLOC", True, when="--enable-replace-malloc")
set_define("MOZ_REPLACE_MALLOC", True, when="--enable-replace-malloc")


@depends(build_project, when="--enable-replace-malloc")
def replace_malloc_static(build_project):
    # Default to statically linking replace-malloc libraries that can be
    # statically linked, except when building with --enable-project=memory.
    if build_project != "memory":
        return True


set_config("MOZ_REPLACE_MALLOC_STATIC", replace_malloc_static)

# PHC (Probabilistic Heap Checker)
# ==============================================================


# In general, it only makes sense for PHC to run on the platforms that have a
# crash reporter.
@depends(
    build_project,
    milestone,
    target,
    when="--enable-jemalloc",
)
def phc_default(build_project, milestone, target):
    if build_project == "js":
        return False

    # Win32 has frequent crashes when stack tracing (for unclear reasons),
    # so PHC is enabled only on 64-bit.  MacOS doesn't have a 32-bit version.
    # Therefore we've only been testing on 64bit processors.
    return (target.cpu in ("x86_64", "aarch64")) and (
        (target.os == "GNU" and target.kernel == "Linux")
        or (target.kernel == "WINNT")
        or (target.os == "OSX")
        or (target.os == "Android" and milestone.is_early_beta_or_earlier)
    )


option(
    "--enable-phc",
    env="MOZ_PHC",
    default=phc_default,
    when="--enable-jemalloc",
    help="{Enable|Disable} PHC (Probabilistic Memory Checker). "
    "Also enables frame pointers when needed",
)

set_config("MOZ_PHC", True, when="--enable-phc")


# PHC parses stacks using frame pointers on these systems.
@depends("--enable-phc", target, have_unwind, when="--enable-jemalloc")
def phc_implies_frame_pointers(phc, target, have_unwind):
    if not phc:
        return False

    # This should be kept in sync with the ifdefs in memory/build/PHC.cpp
    # that control stack walking.
    # This is true for the first two options in PHC.cpp
    if (target.os == "WINNT" and target.cpu == "x86") or target.kernel == "Darwin":
        return True

    # This should match the #defines in mozglue/misc/StackWalk.cpp
    if (target.cpu in ("x86", "ppc")) and (target.kernel in ("Darwin", "Linux")):
        return not have_unwind

    return False


imply_option("--enable-frame-pointers", True, when=phc_implies_frame_pointers)


with only_when(depends(target.os)(lambda os: os != "WINNT")):
    set_define("HAVE_STRNDUP", check_symbol("strndup"))
    set_define("HAVE_POSIX_MEMALIGN", check_symbol("posix_memalign"))
    set_define("HAVE_MEMALIGN", check_symbol("memalign"))

    have_malloc_usable_size = check_symbol("malloc_usable_size")
    set_define("HAVE_MALLOC_USABLE_SIZE", have_malloc_usable_size)


@template
def check_malloc_header():
    found_header = dependable(None)
    malloc_headers = ("malloc.h", "malloc_np.h", "malloc/malloc.h", "sys/malloc.h")
    for malloc_h in malloc_headers:
        have_malloc_h = check_header(malloc_h, when=~found_header)
        found_header = depends(have_malloc_h, found_header)(
            lambda h, f: malloc_h if h else f
        )
    return found_header


malloc_h = check_malloc_header()
have_malloc_h = depends(malloc_h)(lambda h: h == "malloc.h")

set_define("MALLOC_H", depends_if(malloc_h)(lambda h: f"<{h}>"))

usable_size_constness = c_compiler.try_compile(
    includes=depends(malloc_h)(lambda h: [h, "stddef.h"]),
    body="""
        extern size_t malloc_usable_size(const void *ptr);
        return malloc_usable_size(0);
        """,
    check_msg="whether malloc_usable_size definition can use const argument",
    when=have_malloc_usable_size,
)

set_define(
    "MALLOC_USABLE_SIZE_CONST_PTR",
    depends(usable_size_constness, have_malloc_h)(
        lambda u, h: "const" if (u or not h) else ""
    ),
)