85a8c12db8
If we can use comdats, then we can make it so that the global metadata is thrown away if the prevailing definition of the global was uninstrumented. I have only tested this on COFF targets, but in theory, there is no reason that we cannot also do this for ELF. This will allow us to re-enable string merging with ASan on Windows, reducing the binary size cost of ASan on Windows. I tested this change with ASan+PGO, and I fixed an issue with the __llvm_profile_raw_version symbol. With the old version of my patch, we would attempt to instrument that symbol on ELF because it had a comdat with external linkage. If we had been using the linker GC-friendly metadata scheme, everything would have worked, but clang does not enable it by default. llvm-svn: 340232
47 lines
1.9 KiB
LLVM
47 lines
1.9 KiB
LLVM
; RUN: opt < %s -asan -asan-module -S | FileCheck %s
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; Generated like so:
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; $ clang -S -emit-llvm -Xclang -disable-llvm-passes -fsanitize=address -O1 t.cpp -o t.ll
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; const char *getstr() { return "asdf"; }
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; CHECK: $"??_C@_04JIHMPGLA@asdf?$AA@" = comdat any
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; CHECK: @"??_C@_04JIHMPGLA@asdf?$AA@" =
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; CHECK-SAME: linkonce_odr dso_local unnamed_addr constant { [5 x i8], [59 x i8] }
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; CHECK-SAME: { [5 x i8] c"asdf\00", [59 x i8] zeroinitializer }, comdat, align 32
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; CHECK: @"__asan_global_??_C@_04JIHMPGLA@asdf?$AA@" =
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; CHECK-SAME: private global { i64, i64, i64, i64, i64, i64, i64, i64 }
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; CHECK-SAME: { i64 ptrtoint ({ [5 x i8], [59 x i8] }* @"??_C@_04JIHMPGLA@asdf?$AA@" to i64),
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; CHECK-SAME: i64 5, i64 64, i64 ptrtoint ([17 x i8]* @___asan_gen_.1 to i64),
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; CHECK-SAME: i64 ptrtoint ([8 x i8]* @___asan_gen_ to i64), i64 0,
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; CHECK-SAME: i64 ptrtoint ({ [6 x i8]*, i32, i32 }* @___asan_gen_.3 to i64), i64 0 },
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; CHECK-SAME: section ".ASAN$GL", comdat($"??_C@_04JIHMPGLA@asdf?$AA@"), align 64
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; ModuleID = 't.cpp'
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source_filename = "t.cpp"
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target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-pc-windows-msvc19.13.26131"
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$"??_C@_04JIHMPGLA@asdf?$AA@" = comdat any
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@"??_C@_04JIHMPGLA@asdf?$AA@" = linkonce_odr dso_local unnamed_addr constant [5 x i8] c"asdf\00", comdat, align 1
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; Function Attrs: nounwind sanitize_address uwtable
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define dso_local i8* @"?getstr@@YAPEBDXZ"() #0 {
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entry:
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ret i8* getelementptr inbounds ([5 x i8], [5 x i8]* @"??_C@_04JIHMPGLA@asdf?$AA@", i32 0, i32 0)
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}
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attributes #0 = { nounwind sanitize_address uwtable }
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!llvm.asan.globals = !{!0}
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!llvm.module.flags = !{!2, !3}
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!llvm.ident = !{!4}
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!0 = !{[5 x i8]* @"??_C@_04JIHMPGLA@asdf?$AA@", !1, !"<string literal>", i1 false, i1 false}
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!1 = !{!"t.cpp", i32 1, i32 31}
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!2 = !{i32 1, !"wchar_size", i32 2}
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!3 = !{i32 7, !"PIC Level", i32 2}
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!4 = !{!"clang version 7.0.0 "}
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