Add a method of manually specifying the crate map
Apparently weak linkage and dlopen aren't quite working out for applications like servo on android. There appears to be a bug or two in how android loads dynamic libraries and for some reason libservo.so isn't being found. As a temporary solution, add an extern "C" function to libstd which can be called if you have a handle to the crate map manually. When crawling the crate map, we then check this manual symbol before falling back to the old solutions. cc #11731
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@ -8,6 +8,7 @@
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use cast;
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use cmp::TotalOrd;
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use container::MutableSet;
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use iter::Iterator;
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@ -35,6 +36,34 @@ pub struct CrateMap<'a> {
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event_loop_factory: Option<fn() -> ~EventLoop>,
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}
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// When working on android, apparently weak symbols don't work so well for
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// finding the crate map, and neither does dlopen + dlsym. This is mainly a
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// problem when integrating a shared library with an existing application.
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// Standalone binaries do not appear to have this problem. The reasons are a
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// little mysterious, and more information can be found in #11731.
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//
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// For now we provide a way to tell libstd about the crate map manually that's
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// checked before the normal weak symbol/dlopen paths. In theory this is useful
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// on other platforms where our dlopen/weak linkage strategy mysteriously fails
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// but the crate map can be specified manually.
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static mut MANUALLY_PROVIDED_CRATE_MAP: *CrateMap<'static> =
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0 as *CrateMap<'static>;
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#[no_mangle]
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#[cfg(not(test))]
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pub extern fn rust_set_crate_map(map: *CrateMap<'static>) {
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unsafe { MANUALLY_PROVIDED_CRATE_MAP = map; }
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}
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fn manual_crate_map() -> Option<&'static CrateMap<'static>> {
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unsafe {
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if MANUALLY_PROVIDED_CRATE_MAP.is_null() {
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None
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} else {
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Some(cast::transmute(MANUALLY_PROVIDED_CRATE_MAP))
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}
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}
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}
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#[cfg(not(windows))]
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pub fn get_crate_map() -> Option<&'static CrateMap<'static>> {
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extern {
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@ -42,20 +71,26 @@ pub fn get_crate_map() -> Option<&'static CrateMap<'static>> {
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static CRATE_MAP: CrateMap<'static>;
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}
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let ptr: (*CrateMap) = &'static CRATE_MAP;
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if ptr.is_null() {
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return None;
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} else {
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return Some(&'static CRATE_MAP);
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}
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manual_crate_map().or_else(|| {
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let ptr: (*CrateMap) = &'static CRATE_MAP;
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if ptr.is_null() {
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None
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} else {
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Some(&'static CRATE_MAP)
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}
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})
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}
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#[cfg(windows)]
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pub fn get_crate_map() -> Option<&'static CrateMap<'static>> {
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use cast::transmute;
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use c_str::ToCStr;
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use unstable::dynamic_lib::dl;
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match manual_crate_map() {
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Some(cm) => return Some(cm),
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None => {}
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}
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let sym = unsafe {
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let module = dl::open_internal();
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let rust_crate_map_toplevel = if cfg!(target_arch = "x86") {
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@ -74,7 +109,7 @@ pub fn get_crate_map() -> Option<&'static CrateMap<'static>> {
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return None;
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} else {
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unsafe {
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return Some(transmute(sym));
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return Some(cast::transmute(sym));
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}
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}
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}
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@ -0,0 +1,7 @@
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-include ../tools.mk
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all:
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$(RUSTC) lib.rs -C gen-crate-map
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ln -nsf $(call DYLIB,boot-*) $(call DYLIB,boot)
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$(CC) main.c -o $(call RUN,main) -lboot -Wl,-rpath,$(TMPDIR)
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RUST_LOG=boot $(call RUN,main)
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@ -0,0 +1,30 @@
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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#[crate_id="boot#0.1"];
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#[crate_type="dylib"];
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#[no_uv];
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extern crate rustuv;
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extern crate green;
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use std::rt::crate_map::{CrateMap, rust_set_crate_map};
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// pull in this symbol from libstd into this crate (for convenience)
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#[no_mangle]
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pub static set_crate_map: extern "C" fn(*CrateMap<'static>) = rust_set_crate_map;
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#[no_mangle] // this needs to get called from C
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pub extern "C" fn foo(argc: int, argv: **u8) -> int {
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green::start(argc, argv, proc() {
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if log_enabled!(std::logging::DEBUG) { return }
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fail!()
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})
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}
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@ -0,0 +1,20 @@
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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// this is the rust entry point that we're going to call.
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int foo(int argc, char *argv[]);
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extern void (*set_crate_map)(void *map);
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extern int _rust_crate_map_toplevel;
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int main(int argc, char *argv[]) {
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set_crate_map(&_rust_crate_map_toplevel);
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return foo(argc, argv);
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}
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