eecb22d8e1
D130887 uses a dummy empty section `sanmd_covered` (with the SHF_GNU_RETAIN flag on ELF) to prevent `undefined symbol: __start_sanmd_covered` if all `sanmd_covered` are discarded by `ld --gc-sections` (in `-z start-stop-gc` mode). The dummy `sanmd_covered` does not have the SHF_LINK_ORDER flag, so mixing it with SHF_LINK_ORDER `sanmd_covered` causes an issue to GNU ld<2.36 (https://sourceware.org/bugzilla/show_bug.cgi?id=26256). Similar to D98903 for SanitizerCoverage, let's make encapsulation symbols undefined weak[1]. This additionally avoids size cost due to the dummy section and symbol. [1]: https://maskray.me/blog/2021-01-31-metadata-sections-comdat-and-shf-link-order Reviewed By: melver Differential Revision: https://reviews.llvm.org/D139276
37 lines
1.9 KiB
C
37 lines
1.9 KiB
C
// RUN: %clang_cc1 -O -fexperimental-sanitize-metadata=atomics -triple x86_64-gnu-linux -x c -S -emit-llvm %s -o - | FileCheck %s --check-prefixes=CHECK,ATOMICS
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// RUN: %clang_cc1 -O -fexperimental-sanitize-metadata=atomics -triple aarch64-gnu-linux -x c -S -emit-llvm %s -o - | FileCheck %s --check-prefixes=CHECK,ATOMICS
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// CHECK: @__start_sanmd_atomics = extern_weak hidden global ptr
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// CHECK: @__stop_sanmd_atomics = extern_weak hidden global ptr
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// CHECK: @__start_sanmd_covered = extern_weak hidden global ptr
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// CHECK: @__stop_sanmd_covered = extern_weak hidden global ptr
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int x, y;
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void empty() {
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// CHECK-NOT: define dso_local void @empty() {{.*}} !pcsections
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}
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int atomics() {
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// ATOMICS-LABEL: define dso_local i32 @atomics()
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// ATOMICS-SAME: !pcsections ![[ATOMICS_COVERED:[0-9]+]]
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// ATOMICS-NEXT: entry:
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// ATOMICS-NEXT: atomicrmw add {{.*}} !pcsections ![[ATOMIC_OP:[0-9]+]]
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// ATOMICS-NOT: load {{.*}} !pcsections
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__atomic_fetch_add(&x, 1, __ATOMIC_RELAXED);
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return y;
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}
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// ATOMICS-LABEL: __sanitizer_metadata_atomics.module_ctor
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// ATOMICS: call void @__sanitizer_metadata_atomics_add(i32 1, ptr @__start_sanmd_atomics, ptr @__stop_sanmd_atomics)
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// ATOMICS-LABEL: __sanitizer_metadata_atomics.module_dtor
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// ATOMICS: call void @__sanitizer_metadata_atomics_del(i32 1, ptr @__start_sanmd_atomics, ptr @__stop_sanmd_atomics)
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// CHECK-LABEL: __sanitizer_metadata_covered.module_ctor
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// CHECK: call void @__sanitizer_metadata_covered_add(i32 1, ptr @__start_sanmd_covered, ptr @__stop_sanmd_covered)
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// CHECK-LABEL: __sanitizer_metadata_covered.module_dtor
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// CHECK: call void @__sanitizer_metadata_covered_del(i32 1, ptr @__start_sanmd_covered, ptr @__stop_sanmd_covered)
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// ATOMICS: ![[ATOMICS_COVERED]] = !{!"sanmd_covered", ![[ATOMICS_COVERED_AUX:[0-9]+]]}
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// ATOMICS: ![[ATOMICS_COVERED_AUX]] = !{i32 1}
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// ATOMICS: ![[ATOMIC_OP]] = !{!"sanmd_atomics"}
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