rustc: Use link_section, not wasm_custom_section

[alexcrichton]

This commit transitions definitions of custom sections on the wasm target from
the unstable #[wasm_custom_section] attribute to the
already-stable-for-other-targets #[link_section] attribute. Mostly the same
restrictions apply as before, except that this now applies only to statics.

Closes #51088

[rust-highfive]

r? @michaelwoerister

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

[alexcrichton]

cc @eddyb

[eddyb]

cc @oli-obk Should this be in rustc_typeck?

[oli-obk]

Seems fine for now. I can merge it into #51361 once that becomes a thing (since this is more of a constant value validation than a type check)

[eddyb]

LGTM, and I guess rustc_typeck is an okay place to put it.

[rust-highfive]

The job x86_64-gnu-llvm-5.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:start:test_incremental
Check compiletest suite=incremental mode=incremental (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
[00:52:56] 
[00:52:56] running 90 tests
[00:53:09] thread 'main' panicked at 'Some tests failed', tools/compiletest/src/main.rs:498:22
[00:53:09] .........................................................F................................
[00:53:09] 
[00:53:09] ---- [incremental] incremental/issue-49595/issue_49595.rs stdout ----
[00:53:09] 
[00:53:09] 
[00:53:09] error in revision `cfail2`: test compilation failed although it shouldn't!
[00:53:09] status: exit code: 101
[00:53:09] command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/incremental/issue-49595/issue_49595.rs" "--target=x86_64-unknown-linux-gnu" "--cfg" "cfail2" "-C" "incremental=/checkout/obj/build/x86_64-unknown-linux-gnu/test/incremental/issue-49595/issue_49595/issue_49595.inc" "-Z" "incremental-verify-ich" "-Z" "incremental-queries" "--error-format" "json" "-Zui-testing" "-C" "prefer-dynamic" "-o" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/incremental/issue-49595/issue_49595/a" "-Crpath" "-O" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-Z" "query-dep-graph" "--test" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/incremental/issue-49595/issue_49595/auxiliary"
[00:53:09] ------------------------------------------
[00:53:09] 
[00:53:09] ------------------------------------------
[00:53:09] stderr:
[00:53:09] stderr:
[00:53:09] ------------------------------------------
[00:53:09] {"message":"expected module named `issue_49595-tests` to be Codegened but is Reused","code":null,"level":"error","spans":[{"file_name":"/checkout/src/test/incremental/issue-49595/issue_49595.rs","byte_start":612,"byte_end":683,"line_start":18,"line_end":18,"column_start":1,"column_end":72,"is_primary":true,"text":[{"text":"#![rustc_partition_codegened(module=\"issue_49595-tests\", cfg=\"cfail2\")]","highlight_start":1,"highlight_end":72}],"label":null,"suggested_replacement":null,"suggestion_applicability":null,"expansion":null}],"children":[],"rendered":"error: expected module named `issue_49595-tests` to be Codegened but is Reused\n  --> /checkout/src/test/incremental/issue-49595/issue_49595.rs:18:1\n   |\nLL | #![rustc_partition_codegened(module=\"issue_49595-tests\", cfg=\"cfail2\")]\n   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n\n"}
[00:53:09] {"message":"aborting due to previous error","code":null,"level":"error","spans":[],"children":[],"rendered":"error: aborting due to previous error\n\n"}
[00:53:09] ------------------------------------------
[00:53:09] 
[00:53:09] thread '[incremental] incremental/issue-49595/issue_49595.rs' panicked at 'explicit panic', tools/compiletest/src/runtest.rs:3139:9
[00:53:09] note: Run with `RUST_BACKTRACE=1` for a backtrace.
---
[00:53:09] test result: FAILED. 89 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out
[00:53:09] 
[00:53:09] 
[00:53:09] 
[00:53:09] command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/checkout/src/test/incremental" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/incremental" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--mode" "incremental" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/usr/lib/llvm-5.0/bin/FileCheck" "--host-rustcflags" "-Crpath -O -Zunstable-options " "--target-rustcflags" "-Crpath -O -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-hFri, 13 Jul 2018 20:11:44 GMT

The command "date && (curl -fs --head https://google.com | grep ^Date: | sed 's/Date: //g' || true)
" exited with 0.
travis_fold:start:after_failure.1
---
travis_time:end:0031f296:start=1531512706512068392,finish=1531512706520219355,duration=8150963
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:19b13b27
$ head -30 ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
head: cannot open ‘./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers’ for reading: No such file or directory
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:1a1cdef0
$ dmesg | grep -i kill

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[alexcrichton]

@michaelwoerister hm can you help me figure out how to fix the test here? I believe because I've switched to codegen_fn_attrs in a few locations it's causing better cache reuse (yay!) so the test is failing where something was previously regenerated but it no longer is. I've verified locally that the test in question works correctly, though.

For example commenting out the #[ignore] does indeed cause the test to be ignored in the resulting binary, and additionally switching the string constant does indeed print out something different. I think the issue is that something is still recodegen'd on cfail2 for the test (after #[ignore] is added), but I'm not quite sure what. How do I find the name of the module to insert there?

[bors]

☔ The latest upstream changes (presumably #52266) made this pull request unmergeable. Please resolve the merge conflicts.

[alexcrichton]

Ok, I think I figured out the appropriate incantation

[bors]

☔ The latest upstream changes (presumably #52264) made this pull request unmergeable. Please resolve the merge conflicts.

[alexcrichton]

r? @eddyb

[eddyb]

@bors+

[alexcrichton]

@bors: r=eddyb

[bors]

📌 Commit b7ef674 has been approved by eddyb

[bors]

⌛ Testing commit b7ef674 with merge cd5f5a1...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: eddyb
Pushing cd5f5a1 to master...