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Rollup merge of rust-lang#68410 - tmiasko:msan-lto, r=varkor
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Export weak symbols used by MemorySanitizer

Export weak symbols defined by MemorySanitizer instrumentation, which are used
to implement `-Zsanitizer-memory-track-origins` and `-Zsanitizer-recover=memory`.
Previously, when using fat LTO, they would internalized and eliminated.

Fixes rust-lang#68367.
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tmandry authored Jan 22, 2020
2 parents 5801824 + d8c661a commit 0dcea65
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Showing 3 changed files with 52 additions and 22 deletions.
12 changes: 11 additions & 1 deletion src/librustc_codegen_ssa/back/symbol_export.rs
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ use std::sync::Arc;

use rustc::middle::codegen_fn_attrs::CodegenFnAttrFlags;
use rustc::middle::exported_symbols::{metadata_symbol_name, ExportedSymbol, SymbolExportLevel};
use rustc::session::config;
use rustc::session::config::{self, Sanitizer};
use rustc::ty::query::Providers;
use rustc::ty::subst::SubstsRef;
use rustc::ty::Instance;
Expand Down Expand Up @@ -206,6 +206,16 @@ fn exported_symbols_provider_local(
}));
}

if let Some(Sanitizer::Memory) = tcx.sess.opts.debugging_opts.sanitizer {
// Similar to profiling, preserve weak msan symbol during LTO.
const MSAN_WEAK_SYMBOLS: [&str; 2] = ["__msan_track_origins", "__msan_keep_going"];

symbols.extend(MSAN_WEAK_SYMBOLS.iter().map(|sym| {
let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(sym));
(exported_symbol, SymbolExportLevel::C)
}));
}

if tcx.sess.crate_types.borrow().contains(&config::CrateType::Dylib) {
let symbol_name = metadata_symbol_name(tcx);
let exported_symbol = ExportedSymbol::NoDefId(SymbolName::new(&symbol_name));
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6 changes: 5 additions & 1 deletion src/test/codegen/sanitizer-memory-track-orgins.rs
Original file line number Diff line number Diff line change
Expand Up @@ -4,17 +4,21 @@
// needs-sanitizer-support
// only-linux
// only-x86_64
// revisions:MSAN-0 MSAN-1 MSAN-2
// revisions:MSAN-0 MSAN-1 MSAN-2 MSAN-1-LTO MSAN-2-LTO
//
//[MSAN-0] compile-flags: -Zsanitizer=memory
//[MSAN-1] compile-flags: -Zsanitizer=memory -Zsanitizer-memory-track-origins=1
//[MSAN-2] compile-flags: -Zsanitizer=memory -Zsanitizer-memory-track-origins
//[MSAN-1-LTO] compile-flags: -Zsanitizer=memory -Zsanitizer-memory-track-origins=1 -C lto=fat
//[MSAN-2-LTO] compile-flags: -Zsanitizer=memory -Zsanitizer-memory-track-origins -C lto=fat

#![crate_type="lib"]

// MSAN-0-NOT: @__msan_track_origins
// MSAN-1: @__msan_track_origins = weak_odr local_unnamed_addr constant i32 1
// MSAN-2: @__msan_track_origins = weak_odr local_unnamed_addr constant i32 2
// MSAN-1-LTO: @__msan_track_origins = weak_odr local_unnamed_addr constant i32 1
// MSAN-2-LTO: @__msan_track_origins = weak_odr local_unnamed_addr constant i32 2
//
// MSAN-0-LABEL: define void @copy(
// MSAN-1-LABEL: define void @copy(
Expand Down
56 changes: 36 additions & 20 deletions src/test/codegen/sanitizer-recover.rs
Original file line number Diff line number Diff line change
Expand Up @@ -4,31 +4,47 @@
// needs-sanitizer-support
// only-linux
// only-x86_64
// revisions:ASAN ASAN-RECOVER MSAN MSAN-RECOVER
// revisions:ASAN ASAN-RECOVER MSAN MSAN-RECOVER MSAN-RECOVER-LTO
// no-prefer-dynamic
//
//[ASAN] compile-flags: -Zsanitizer=address
//[ASAN-RECOVER] compile-flags: -Zsanitizer=address -Zsanitizer-recover=address
//[MSAN] compile-flags: -Zsanitizer=memory
//[MSAN-RECOVER] compile-flags: -Zsanitizer=memory -Zsanitizer-recover=memory

#![crate_type="lib"]
//[ASAN] compile-flags: -Zsanitizer=address
//[ASAN-RECOVER] compile-flags: -Zsanitizer=address -Zsanitizer-recover=address
//[MSAN] compile-flags: -Zsanitizer=memory
//[MSAN-RECOVER] compile-flags: -Zsanitizer=memory -Zsanitizer-recover=memory
//[MSAN-RECOVER-LTO] compile-flags: -Zsanitizer=memory -Zsanitizer-recover=memory -C lto=fat
//
// MSAN-NOT: @__msan_keep_going
// MSAN-RECOVER: @__msan_keep_going = weak_odr {{.*}} constant i32 1
// MSAN-RECOVER-LTO: @__msan_keep_going = weak_odr {{.*}} constant i32 1

// ASAN-LABEL: define i32 @penguin(
// ASAN-LABEL: define i32 @penguin(
// ASAN: call void @__asan_report_load4(i64 %0)
// ASAN: unreachable
// ASAN: }
//
// ASAN-RECOVER-LABEL: define i32 @penguin(
// MSAN-LABEL: define i32 @penguin(
// ASAN-RECOVER: call void @__asan_report_load4_noabort(
// ASAN-RECOVER-NOT: unreachable
// ASAN: }
//
// MSAN-LABEL: define i32 @penguin(
// MSAN: call void @__msan_warning_noreturn()
// MSAN: unreachable
// MSAN: }
//
// MSAN-RECOVER-LABEL: define i32 @penguin(
// MSAN-RECOVER: call void @__msan_warning()
// MSAN-RECOVER-NOT: unreachable
// MSAN-RECOVER: }
//
// MSAN-RECOVER-LTO-LABEL: define i32 @penguin(
// MSAN-RECOVER-LTO: call void @__msan_warning()
// MSAN-RECOVER-LTO-NOT: unreachable
// MSAN-RECOVER-LTO: }
//
#[no_mangle]
pub fn penguin(p: &mut i32) -> i32 {
// ASAN: call void @__asan_report_load4(i64 %0)
// ASAN: unreachable
//
// ASAN-RECOVER: call void @__asan_report_load4_noabort(
// ASAN-RECOVER-NOT: unreachable
//
// MSAN: call void @__msan_warning_noreturn()
// MSAN: unreachable
//
// MSAN-RECOVER: call void @__msan_warning()
// MSAN-RECOVER-NOT: unreachable
*p
}

fn main() {}

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