rustc: Handle `#[no_mangle]` anywhere in a crate by alexcrichton · Pull Request #45189 · rust-lang/rust

alexcrichton · 2017-10-10T22:56:21Z

This commit updates the reachability pass of the compiler to seed the local
worklist with #[no_mangle]-like items anywhere in a crate, not just those
reachable from public items.

Closes#45165

alexcrichton · 2017-10-10T22:56:29Z

r? @michaelwoerister

rust-highfive · 2017-10-10T22:56:33Z

r? @pnkfelix

(rust_highfive has picked a reviewer for you, use r? to override)

michaelwoerister · 2017-10-11T08:31:45Z

Looks good to me. Some tests are failing though.

alexcrichton · 2017-10-11T16:02:29Z

Ok I changed this to just handling #[linkage] instead of #[no_mangle] which I believe should fix the tests.

@bors: r=michaelwoerister

bors · 2017-10-11T16:02:29Z

📌 Commit c7aa741 has been approved by michaelwoerister

…michaelwoerister rustc: Handle `#[no_mangle]` anywhere in a crate This commit updates the reachability pass of the compiler to seed the local worklist with `#[no_mangle]`-like items anywhere in a crate, not just those reachable from public items. Closesrust-lang#45165

kennytm · 2017-10-12T08:09:29Z

@bors r-

asm.js's run-pass/smallest-hello-world.rs test failed to link due to "undefined symbol: rust_begin_unwind" in rollup #45207 (Travis log: https://travis-ci.org/rust-lang/rust/jobs/286875799).

The test involves #[global_allocator] and only this PR touches the linkage step, so I guess this should be the cause. The rollup uses c7aa741 so it should not be due to the #[no_mangle].

Details

[01:37:33] ---- [run-pass] run-pass/smallest-hello-world.rs stdout ----
[01:37:33] [01:37:33] error: compilation failed!
[01:37:33] status: exit code: 101
[01:37:33] command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/run-pass/smallest-hello-world.rs" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass" "--target=asmjs-unknown-emscripten" "-C" "prefer-dynamic" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass/smallest-hello-world.stage2-asmjs-unknown-emscripten.js" "-Crpath" "-O" "-Lnative=/checkout/obj/build/asmjs-unknown-emscripten/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass/smallest-hello-world.stage2-asmjs-unknown-emscripten.run-pass.libaux"
[01:37:33] stdout:
[01:37:33] ------------------------------------------
[01:37:33] [01:37:33] ------------------------------------------
[01:37:33] stderr:
[01:37:33] ------------------------------------------
[01:37:33] error: linking with `emcc` failed: exit code: 1
[01:37:33] |
[01:37:33] = note: "emcc" "-s" "DISABLE_EXCEPTION_CATCHING=0" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/asmjs-unknown-emscripten/lib" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass/smallest-hello-world.smallest_hello_world0.rust-cgu.o" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass/smallest-hello-world.stage2-asmjs-unknown-emscripten.js" "-s" "EXPORTED_FUNCTIONS=[\"___rg_shrink_in_place\",\"___rg_alloc\",\"___rg_oom\",\"___rg_realloc\",\"___rg_alloc_zeroed\",\"_rust_eh_personality\",\"___rg_usable_size\",\"___rg_alloc_excess\",\"___rg_grow_in_place\",\"___rg_dealloc\",\"___rg_realloc_excess\",\"_main\"]" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass/smallest-hello-world.crate.allocator.rust-cgu.o" "-O2" "--memory-init-file" "0" "-g0" "-s" "DEFAULT_LIBRARY_FUNCS_TO_INCLUDE=[]" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass" "-L" "/checkout/obj/build/asmjs-unknown-emscripten/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/run-pass/smallest-hello-world.stage2-asmjs-unknown-emscripten.run-pass.libaux" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/asmjs-unknown-emscripten/lib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/asmjs-unknown-emscripten/lib/liballoc_system-67992b04c9027e70.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/asmjs-unknown-emscripten/lib/liballoc-c15d9e20191e711b.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/asmjs-unknown-emscripten/lib/libstd_unicode-b3230a4723442795.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/asmjs-unknown-emscripten/lib/liblibc-bdd38e4620ffab1c.rlib" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/asmjs-unknown-emscripten/lib/libcore-3181dd9e46400ebd.rlib" "-l" "c" "-s" "ERROR_ON_UNDEFINED_SYMBOLS=1"
[01:37:33] = note: error: unresolved symbol: rust_begin_unwind
[01:37:33] Aborting compilation due to previous errors | undefined
[01:37:33] Traceback (most recent call last):
[01:37:33] File "/emsdk-portable/emscripten/1.37.13//emcc", line 13, in <module>
[01:37:33] emcc.run()
[01:37:33] File "/emsdk-portable/emscripten/1.37.13/emcc.py", line 1526, in run
[01:37:33] final = shared.Building.emscripten(final, append_ext=False, extra_args=extra_args)
[01:37:33] File "/emsdk-portable/emscripten/1.37.13/tools/shared.py", line 1963, in emscripten
[01:37:33] call_emscripten(cmdline)
[01:37:33] File "/emsdk-portable/emscripten/1.37.13/emscripten.py", line 2190, in _main
[01:37:33] temp_files.run_and_clean(lambda: main(
[01:37:33] File "/emsdk-portable/emscripten/1.37.13/tools/tempfiles.py", line 78, in run_and_clean
[01:37:33] return func()
[01:37:33] File "/emsdk-portable/emscripten/1.37.13/emscripten.py", line 2195, in <lambda>
[01:37:33] DEBUG=DEBUG,
[01:37:33] File "/emsdk-portable/emscripten/1.37.13/emscripten.py", line 2095, in main
[01:37:33] temp_files=temp_files, DEBUG=DEBUG)
[01:37:33] File "/emsdk-portable/emscripten/1.37.13/emscripten.py", line 98, in emscript
[01:37:33] glue, forwarded_data = compiler_glue(metadata, settings, libraries, compiler_engine, temp_files, DEBUG)
[01:37:33] File "/emsdk-portable/emscripten/1.37.13/emscripten.py", line 219, in compiler_glue
[01:37:33] glue, forwarded_data = compile_settings(compiler_engine, settings, libraries, temp_files)
[01:37:33] File "/emsdk-portable/emscripten/1.37.13/emscripten.py", line 531, in compile_settings
[01:37:33] cwd=path_from_root('src'), error_limit=300)
[01:37:33] File "/emsdk-portable/emscripten/1.37.13/tools/jsrun.py", line 128, in run_js
[01:37:33] raise Exception('Expected the command ' + str(command) + ' to finish with return code ' + str(assert_returncode) + ', but it returned with code ' + str(proc.returncode) + ' instead! Output: ' + str(ret)[:error_limit])
[01:37:33] Exception: Expected the command ['/emsdk-portable/node/4.1.1_64bit/bin/node', '/emsdk-portable/emscripten/1.37.13/src/compiler.js', '/tmp/tmp1WwN3A.txt', '/emsdk-portable/emscripten/1.37.13/src/library_pthread_stub.js'] to finish with return code 0, but it returned with code 1 instead! Output: // The Module object: Our interface to the outside world. We import
[01:37:33] // and export values on it, and do the work to get that through
[01:37:33] // closure compiler if necessary. There are various ways Module can be used:
[01:37:33] // 1. Not defined. We create it here
[01:37:33] // 2. A function parameter, function(Module) { ..gener
[01:37:33] [01:37:33] [01:37:33] error: aborting due to previous error
[01:37:33] [01:37:33] [01:37:33] ------------------------------------------
[01:37:33] [01:37:33] thread '[run-pass] run-pass/smallest-hello-world.rs' panicked at 'explicit panic', /checkout/src/tools/compiletest/src/runtest.rs:2425:8
[01:37:33] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[01:37:33] [01:37:33] [01:37:33] failures:
[01:37:33] [run-pass] run-pass/smallest-hello-world.rs
[01:37:33] [01:37:33] test result: FAILED. 2643 passed; 1 failed; 145 ignored; 0 measured; 0 filtered out

michaelwoerister · 2017-10-12T11:15:56Z

@alexcrichton So what exactly is going on here? I.e. what is the root cause of the problem this PR tries to fix?

alexcrichton · 2017-10-12T14:57:20Z

@michaelwoerister the problem is that ThinLTO is internalizing these symbols when they otherwise need to be exposed. That in turns happens because locally defined allocator symbols aren't in the list of "rust exported symbols" (the exported_symbols) query. That happens because they're not in the reachable set. That then finally happens because reachability doesn't take #[linkage] (an unstable attribute) into account.

michaelwoerister · 2017-10-12T15:32:57Z

@alexcrichton But why is that a problem with ThinLTO but not the regular multi-CGU case?

alexcrichton · 2017-10-12T16:13:05Z

I think that happens is that in normal trans we will translate everything to LLVM and at that time we'll recognize #[linkage] and apply it. With ThinLTO enabled, however, the items in each CGU will get its linkage/visibility frobbed by the various passes. We instruct ThinLTO to only retain a particular set of symbols, and the allocator functions aren't in this set (hence this bug)

Does that make sense?

This commit updates the reachability pass of the compiler to seed the local worklist with `#[linkage]`-like items anywhere in a crate, not just those reachable from public items. Closesrust-lang#45165

alexcrichton · 2017-10-12T16:14:48Z

Also I'm removing that test once and for all, it has caused dozens and dozens of failures and has literally never caught a regression.

@bors: r=michaelwoerister

bors · 2017-10-12T16:14:49Z

📌 Commit 6cae080 has been approved by michaelwoerister

michaelwoerister · 2017-10-12T16:23:31Z

Also I'm removing that test once and for all, it has caused dozens and dozens of failures and has literally never caught a regression.

:D

michaelwoerister · 2017-10-12T16:23:51Z

Thanks for the clarification.

…michaelwoerister rustc: Handle `#[no_mangle]` anywhere in a crate This commit updates the reachability pass of the compiler to seed the local worklist with `#[no_mangle]`-like items anywhere in a crate, not just those reachable from public items. Closesrust-lang#45165

Rollup of 14 pull requests - Successful merges: #44855, #45110, #45122, #45133, #45173, #45178, #45189, #45203, #45209, #45221, #45236, #45240, #45245, #45253 - Failed merges:

rust-highfive assigned pnkfelix Oct 10, 2017

rust-highfive assigned michaelwoerister and unassigned pnkfelix Oct 10, 2017

alexcrichton force-pushed the thinlto-allocators branch from 1b8e3de to c7aa741Compare October 11, 2017 16:02

kennytm mentioned this pull request Oct 11, 2017
Rollup of 8 pull requests #45207
Closed

aidanhs added the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Oct 12, 2017

rustc: Handle #[linkage] anywhere in a crate
6cae080
This commit updates the reachability pass of the compiler to seed the local worklist with `#[linkage]`-like items anywhere in a crate, not just those reachable from public items. Closesrust-lang#45165

alexcrichton force-pushed the thinlto-allocators branch from c7aa741 to 6cae080Compare October 12, 2017 16:14

kennytm mentioned this pull request Oct 13, 2017
Rollup of 14 pull requests #45261
Merged

bors merged commit 6cae080 into rust-lang:masterOct 13, 2017

alexcrichton deleted the thinlto-allocators branch October 14, 2017 02:38

Uh oh!

Uh oh!

Conversation

alexcrichton commented Oct 10, 2017

Uh oh!

alexcrichton commented Oct 10, 2017

Uh oh!

rust-highfive commented Oct 10, 2017

Uh oh!

michaelwoerister commented Oct 11, 2017

Uh oh!

alexcrichton commented Oct 11, 2017

Uh oh!

bors commented Oct 11, 2017

Uh oh!

kennytm commented Oct 12, 2017

Uh oh!

michaelwoerister commented Oct 12, 2017

Uh oh!

alexcrichton commented Oct 12, 2017

Uh oh!

michaelwoerister commented Oct 12, 2017

Uh oh!

alexcrichton commented Oct 12, 2017

Uh oh!

alexcrichton commented Oct 12, 2017

Uh oh!

bors commented Oct 12, 2017

Uh oh!

michaelwoerister commented Oct 12, 2017

Uh oh!

michaelwoerister commented Oct 12, 2017

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

7 participants