Rollup merge of rust-lang#114642 - anforowicz:fix-asan-lto, r=tmiasko

Mark `___asan_globals_registered` as an exported symbol for LTO

Export a weak symbol defined by AddressSanitizer instrumentation.
Previously, when using LTO, the symbol would get internalized and eliminated.

Fixes rust-lang#113404.

---------------

FWIW, let me list similar PRs from the past + who reviewed them:

* rust-lang#68410 (fixing `__msan_keep_going` and `__msan_track_origins`; reviewed by ``@varkor)``
* rust-lang#60038 and rust-lang#48346 (fixing `__llvm_profile_raw_version` and `__llvm_profile_filename`; reviewed by ``@alexcrichton)``

compiler/rustc_codegen_ssa/src/back/symbol_export.rs

@@ -245,50 +245,41 @@ fn exported_symbols_provider_local(
         ))
     }
 
+    // Rust assumes that all code provided to (non-plugin) LTO comes from Rust, so it knows about
+    // all symbols that are involved. This doesn't hold up for symbols that get injected by LLVM,
+    // so they need to be special-cased.
+    let mut externally_injected_weak_symbols = Vec::new();
     if tcx.sess.instrument_coverage() || tcx.sess.opts.cg.profile_generate.enabled() {
         // These are weak symbols that point to the profile version and the
         // profile name, which need to be treated as exported so LTO doesn't nix
         // them.
-        const PROFILER_WEAK_SYMBOLS: [&str; 2] =
-            ["__llvm_profile_raw_version", "__llvm_profile_filename"];
-
-        symbols.extend(PROFILER_WEAK_SYMBOLS.iter().map(|sym| {
-            let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, sym));
-            (
-                exported_symbol,
-                SymbolExportInfo {
-                    level: SymbolExportLevel::C,
-                    kind: SymbolExportKind::Data,
-                    used: false,
-                },
-            )
-        }));
+        externally_injected_weak_symbols.push("__llvm_profile_raw_version");
+        externally_injected_weak_symbols.push("__llvm_profile_filename");
     }
-
     if tcx.sess.opts.unstable_opts.sanitizer.contains(SanitizerSet::MEMORY) {
-        let mut msan_weak_symbols = Vec::new();
-
         // Similar to profiling, preserve weak msan symbol during LTO.
         if tcx.sess.opts.unstable_opts.sanitizer_recover.contains(SanitizerSet::MEMORY) {
-            msan_weak_symbols.push("__msan_keep_going");
+            externally_injected_weak_symbols.push("__msan_keep_going");
         }
-
         if tcx.sess.opts.unstable_opts.sanitizer_memory_track_origins != 0 {
-            msan_weak_symbols.push("__msan_track_origins");
+            externally_injected_weak_symbols.push("__msan_track_origins");
         }
-
-        symbols.extend(msan_weak_symbols.into_iter().map(|sym| {
-            let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, sym));
-            (
-                exported_symbol,
-                SymbolExportInfo {
-                    level: SymbolExportLevel::C,
-                    kind: SymbolExportKind::Data,
-                    used: false,
-                },
-            )
-        }));
     }
+    if tcx.sess.opts.unstable_opts.sanitizer.contains(SanitizerSet::ADDRESS) {
+        // Similar to profiling, preserve weak asan symbols during LTO.
+        externally_injected_weak_symbols.push("___asan_globals_registered");
+    }
+    symbols.extend(externally_injected_weak_symbols.into_iter().map(|sym| {
+        let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(tcx, sym));
+        (
+            exported_symbol,
+            SymbolExportInfo {
+                level: SymbolExportLevel::C,
+                kind: SymbolExportKind::Data,
+                used: false,
+            },
+        )
+    }));
 
     if tcx.crate_types().contains(&CrateType::Dylib)
         || tcx.crate_types().contains(&CrateType::ProcMacro)

tests/codegen/sanitizer/address-sanitizer-globals-tracking.rs

@@ -0,0 +1,36 @@
+// Verifies that AddressSanitizer symbols show up as expected in LLVM IR
+// with -Zsanitizer (DO NOT SUBMIT: add ASAN (no LTO) and ASAN-LTO2 (lto=fat) tests).
+//
+// Notes about the `compile-flags` below:
+//
+// * The original issue only reproed with LTO - this is why this angle has
+//   extra test coverage via different `revisions`
+// * To observe the failure/repro at LLVM-IR level we need to use `staticlib`
+//   which necessitates `-C prefer-dynamic=false` - without the latter flag,
+//   we would have run into "cannot prefer dynamic linking when performing LTO".
+//
+// needs-sanitizer-address
+//
+// revisions:ASAN ASAN-LTO
+//[ASAN]     compile-flags: -Zsanitizer=address
+//[ASAN-LTO] compile-flags: -Zsanitizer=address -C prefer-dynamic=false -C lto
+
+#![crate_type="staticlib"]
+
+// The test below mimics `CACHED_POW10` from `library/core/src/num/flt2dec/strategy/grisu.rs` which
+// (because of incorrect handling of `___asan_globals_registered` during LTO) was incorrectly
+// reported as an ODR violation in https://crbug.com/1459233#c1.  Before this bug was fixed,
+// `___asan_globals_registered` would show up as `internal global i64`.
+//
+// See https://github.com/rust-lang/rust/issues/113404 for more discussion.
+//
+// CHECK: @___asan_globals_registered = common hidden global i64 0
+// CHECK: @__start_asan_globals = extern_weak hidden global i64
+// CHECK: @__stop_asan_globals = extern_weak hidden global i64
+#[no_mangle]
+pub static CACHED_POW10: [(u64, i16, i16); 4] = [
+    (0xe61acf033d1a45df, -1087, -308),
+    (0xab70fe17c79ac6ca, -1060, -300),
+    (0xff77b1fcbebcdc4f, -1034, -292),
+    (0xbe5691ef416bd60c, -1007, -284),
+];