9558456b53
On ELF, we place the metadata sections (`__sancov_guards`, `__sancov_cntrs`,
`__sancov_bools`, `__sancov_pcs` in section groups (either `comdat any` or
`comdat noduplicates`).
With `--gc-sections`, LLD since D96753 and GNU ld `-z start-stop-gc` may garbage
collect such sections. If all `__sancov_bools` are discarded, LLD will error
`error: undefined hidden symbol: __start___sancov_cntrs` (other sections are similar).
```
% cat a.c
void discarded() {}
% clang -fsanitize-coverage=func,trace-pc-guard -fpic -fvisibility=hidden a.c -shared -fuse-ld=lld -Wl,--gc-sections
...
ld.lld: error: undefined hidden symbol: __start___sancov_guards
>>> referenced by a.c
>>> /tmp/a-456662.o:(sancov.module_ctor_trace_pc_guard)
```
Use the `extern_weak` linkage (lowered to undefined weak symbols) to avoid the
undefined error.
Differential Revision: https://reviews.llvm.org/D98903
30 lines
1.9 KiB
LLVM
30 lines
1.9 KiB
LLVM
; Test -sanitizer-coverage-pc-table=1
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; RUN: opt < %s -sancov -sanitizer-coverage-level=3 -sanitizer-coverage-trace-pc-guard -sanitizer-coverage-pc-table=1 -S -enable-new-pm=0 | FileCheck %s
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; RUN: opt < %s -sancov -sanitizer-coverage-level=3 -sanitizer-coverage-inline-8bit-counters -sanitizer-coverage-pc-table=1 -S -enable-new-pm=0 | FileCheck %s
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; RUN: opt < %s -sancov -sanitizer-coverage-level=3 -sanitizer-coverage-inline-bool-flag -sanitizer-coverage-pc-table=1 -S -enable-new-pm=0 | FileCheck %s
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; RUN: opt < %s -passes='module(sancov-module)' -sanitizer-coverage-level=3 -sanitizer-coverage-trace-pc-guard -sanitizer-coverage-pc-table=1 -S | FileCheck %s
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; RUN: opt < %s -passes='module(sancov-module)' -sanitizer-coverage-level=3 -sanitizer-coverage-inline-8bit-counters -sanitizer-coverage-pc-table=1 -S | FileCheck %s
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; RUN: opt < %s -passes='module(sancov-module)' -sanitizer-coverage-level=3 -sanitizer-coverage-inline-bool-flag -sanitizer-coverage-pc-table=1 -S | FileCheck %s
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target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
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target triple = "x86_64-unknown-linux-gnu"
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define void @foo(i32* %a) sanitize_address {
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entry:
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%tobool = icmp eq i32* %a, null
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br i1 %tobool, label %if.end, label %if.then
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if.then: ; preds = %entry
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store i32 0, i32* %a, align 4
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br label %if.end
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if.end: ; preds = %entry, %if.then
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ret void
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}
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; CHECK: private constant [6 x i64*] [{{.*}}@foo{{.*}}blockaddress{{.*}}blockaddress{{.*}}], section "__sancov_pcs", comdat($foo), align 8
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; CHECK: @__start___sancov_pcs = extern_weak hidden global i64
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; CHECK-NEXT: @__stop___sancov_pcs = extern_weak hidden global i64
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; CHECK: define internal void @sancov.module_ctor
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; CHECK: call void @__sanitizer_cov
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; CHECK: call void @__sanitizer_cov_pcs_init
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