Allow disabling ASan instrumentation for globals

[BertalanD]

AddressSanitizer adds instrumentation to global variables unless the no_sanitize_address attribute is set on them.

This commit extends the existing #[no_sanitize(address)] attribute to set this; previously it only had the desired effect on functions.

(cc #39699)

[rustbot]

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[rustbot]

Some changes occurred in tests/codegen/sanitizer

cc @rust-lang/project-exploit-mitigations, @rcvalle

[rcvalle]

LGTM (@cuviper FYI). We'll want this for #123617. Thank you for your time and for working on this, @BertalanD! Much appreciated.

[rcvalle]

@BertalanD do you know if there is anything else possibly missing instrumentation before #123617?

[BertalanD]

Thank you for reviewing; I pushed up the suggested style change.

I haven't looked into missing instrumentation, so I can't help with that. But what might be relevant for stabilization is that this came up in the context of a Chromium issue where the added ASan annotation on #[small_ctor::ctor] items resulted in link-time crashes and run-time failures on Apple platforms.

[rcvalle]

Thank you for the information and for sending it out, @BertalanD! I'll take a look.

[BertalanD]

@rcvalle

ctor and linkme are two other crates that will definitely be impacted by ASan annotation on global variables (alongside small_ctor).

The operation of all three basically boils down to creating a special section in the output file that's an array of pointers, by creating static variables annotated with #[link_section]. The ASan instrumentation pads these to 32 bytes, filling the rest with zeros. So the code that traverses the array will either stop processing them when encountering the zeros (this is what dyld does for me on macOS 15), or crash with a null deref in the worst case.

[bors]

☔ The latest upstream changes (presumably #127831) made this pull request unmergeable. Please resolve the merge conflicts.

[rust-log-analyzer]

The job x86_64-gnu-llvm-17 failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

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 > importing cache manifest from ghcr.io/rust-lang/rust-ci-cache:fb97a1d6377f6cf2227825318ca4bbde3889e0c420746f5a03ba46a07e9a862725c26a09b9fc49a0d129ebd75935d3f6cd19acf41cc4267a6846fd4aa574b12c:
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##[endgroup]
Setting extra environment values for docker:  --env ENABLE_GCC_CODEGEN=1 --env GCC_EXEC_PREFIX=/usr/lib/gcc/
[CI_JOB_NAME=x86_64-gnu-llvm-17]
---
sccache: Starting the server...
##[group]Configure the build
configure: processing command line
configure: 
configure: build.configure-args := ['--build=x86_64-unknown-linux-gnu', '--llvm-root=/usr/lib/llvm-17', '--enable-llvm-link-shared', '--set', 'rust.randomize-layout=true', '--set', 'rust.thin-lto-import-instr-limit=10', '--set', 'change-id=99999999', '--enable-verbose-configure', '--enable-sccache', '--disable-manage-submodules', '--enable-locked-deps', '--enable-cargo-native-static', '--set', 'rust.codegen-units-std=1', '--set', 'dist.compression-profile=balanced', '--dist-compression-formats=xz', '--set', 'rust.lld=false', '--disable-dist-src', '--release-channel=nightly', '--enable-debug-assertions', '--enable-overflow-checks', '--enable-llvm-assertions', '--set', 'rust.verify-llvm-ir', '--set', 'rust.codegen-backends=llvm,cranelift,gcc', '--set', 'llvm.static-libstdcpp', '--enable-new-symbol-mangling']
configure: target.x86_64-unknown-linux-gnu.llvm-config := /usr/lib/llvm-17/bin/llvm-config
configure: llvm.link-shared     := True
configure: rust.randomize-layout := True
configure: rust.thin-lto-import-instr-limit := 10
---
---- [ui] tests/ui/attributes/no-sanitize.rs stdout ----

error: ui test compiled successfully!
status: exit status: 0
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/attributes/no-sanitize.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2" "--target=x86_64-unknown-linux-gnu" "--check-cfg" "cfg(FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/attributes/no-sanitize" "-A" "unused" "-A" "internal_features" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/attributes/no-sanitize/auxiliary"
stderr: none