1ada819c23
This enables odr indicators on all platforms and private aliases on non-Windows. Note that GCC also uses private aliases: this fixes bogus `The following global variable is not properly aligned.` errors for interposed global variables Fix https://github.com/google/sanitizers/issues/398 Fix https://github.com/google/sanitizers/issues/1017 Fix https://github.com/llvm/llvm-project/issues/36893 (we can restore D46665) Global variables of non-hasExactDefinition() linkages (i.e. linkonce/linkonce_odr/weak/weak_odr/common/external_weak) are not instrumented. If an instrumented variable gets interposed to an uninstrumented variable due to symbol interposition (e.g. in issue 36893, _ZTS1A in foo.so is resolved to _ZTS1A in the executable), there may be a bogus error. With private aliases, the register code will not resolve to a definition in another module, and thus prevent the issue. Cons: minor size increase. This is mainly due to extra `__odr_asan_gen_*` symbols. (ELF) In addition, in relocatable files private aliases replace some relocations referencing global symbols with .L symbols and may introduce some STT_SECTION symbols. For lld, with -g0, the size increase is 0.07~0.09% for many configurations I have tested: -O0, -O1, -O2, -O3, -O2 -ffunction-sections -fdata-sections -Wl,--gc-sections. With -g1 or above, the size increase ratio will be even smaller. This patch obsoletes D92078. Don't migrate Windows for now: the static data member of a specialization `std::num_put<char>::id` is a weak symbol, as well as its ODR indicator. Unfortunately, link.exe (and lld without -lldmingw) generally doesn't support duplicate weak definitions (weak symbols in different TUs likely pick different defined external symbols and conflict). Differential Revision: https://reviews.llvm.org/D137227
90 lines
4.4 KiB
LLVM
90 lines
4.4 KiB
LLVM
; Check that we disable the use of comdat sections for the garbage collection
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; of globals.
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; This is to avoid false negative ODR violations detection at link time.
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; We keep using comdats for garbage collection if odr indicators are
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; enabled as indicator symbols will cause link time odr violations.
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; This is to fix PR 47925.
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;
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; RUN: opt < %s -passes=asan -asan-globals-live-support=1 -asan-use-odr-indicator=0 -S | FileCheck %s --check-prefixes=CHECK,NOCOMDAT
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; Check that enabling odr indicators enables comdat for globals.
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; RUN: opt < %s -passes=asan -asan-globals-live-support=1 -S | FileCheck %s --check-prefixes=CHECK,COMDAT
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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; Globals:
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@global = global i32 0, align 4
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@dyn_init_global = global i32 0, align 4
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@blocked_global = global i32 0, align 4
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@_ZZ4funcvE10static_var = internal global i32 0, align 4
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@.str = private unnamed_addr constant [14 x i8] c"Hello, world!\00", align 1
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@llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 65535, ptr @_GLOBAL__sub_I_asan_globals.cpp, ptr null }]
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; Check that globals were instrumented:
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; COMDAT: $global = comdat any
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; COMDAT: $dyn_init_global = comdat any
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; COMDAT: $_ZZ4funcvE10static_var.{{[01-9a-f]+}} = comdat any
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; COMDAT: $.str.{{[01-9a-f]+}} = comdat any
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; NOCOMDAT-NOT: $global = comdat any
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; NOCOMDAT-NOT: $dyn_init_global = comdat any
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; NOCOMDAT-NOT: $_ZZ4funcvE10static_var.{{[01-9a-f]+}} = comdat any
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; NOCOMDAT-NOT: $.str.{{[01-9a-f]+}} = comdat any
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; COMDAT: @global = global { i32, [28 x i8] } zeroinitializer, comdat, align 32
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; COMDAT: @dyn_init_global = global { i32, [28 x i8] } zeroinitializer, comdat, align 32
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; COMDAT: @_ZZ4funcvE10static_var = internal global { i32, [28 x i8] } zeroinitializer, comdat($_ZZ4funcvE10static_var.{{[01-9a-f]+}}), align 32
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; COMDAT: @.str = internal constant { [14 x i8], [18 x i8] } { [14 x i8] c"Hello, world!\00", [18 x i8] zeroinitializer }, comdat($.str.{{[01-9a-f]+}}), align 32
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; NOCOMDAT: @global = global { i32, [28 x i8] } zeroinitializer, align 32
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; NOCOMDAT: @dyn_init_global = global { i32, [28 x i8] } zeroinitializer, align 32
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; NOCOMDAT: @_ZZ4funcvE10static_var = internal global { i32, [28 x i8] } zeroinitializer, align 32
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; NOCOMDAT: @.str = internal constant { [14 x i8], [18 x i8] } { [14 x i8] c"Hello, world!\00", [18 x i8] zeroinitializer }, align 32
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; Check emitted location descriptions:
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; CHECK: [[VARNAME:@___asan_gen_.[0-9]+]] = private unnamed_addr constant [7 x i8] c"global\00", align 1
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; COMDAT: @__asan_global_global = {{.*}}i64 ptrtoint (ptr @__odr_asan_gen_global to i64){{.*}} section "asan_globals"{{.*}}, comdat($global), !associated
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; COMDAT: @__asan_global_.str = {{.*}}i64 ptrtoint (ptr @___asan_gen_ to i64){{.*}} section "asan_globals"{{.*}}, comdat($.str.{{.*}}), !associated
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; The metadata has to be inserted to llvm.compiler.used to avoid being stripped
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; during LTO.
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; CHECK: @llvm.compiler.used {{.*}} ptr @__asan_global_global, {{.*}} section "llvm.metadata"
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; Check that location descriptors and global names were passed into __asan_register_globals:
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; CHECK: call void @__asan_register_elf_globals(i64 ptrtoint (ptr @___asan_globals_registered to i64), i64 ptrtoint (ptr @__start_asan_globals to i64), i64 ptrtoint (ptr @__stop_asan_globals to i64))
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; Function Attrs: nounwind sanitize_address
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define internal void @__cxx_global_var_init() #0 section ".text.startup" {
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entry:
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%0 = load i32, ptr @global, align 4
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store i32 %0, ptr @dyn_init_global, align 4
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ret void
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}
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; Function Attrs: nounwind sanitize_address
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define void @_Z4funcv() #1 {
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entry:
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%literal = alloca ptr, align 8
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store ptr @.str, ptr %literal, align 8
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ret void
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}
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; Function Attrs: nounwind sanitize_address
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define internal void @_GLOBAL__sub_I_asan_globals.cpp() #0 section ".text.startup" {
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entry:
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call void @__cxx_global_var_init()
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ret void
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}
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attributes #0 = { nounwind sanitize_address }
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attributes #1 = { nounwind sanitize_address "less-precise-fpmad"="false" "frame-pointer"="none" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-realign-stack" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
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!llvm.ident = !{!5}
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!5 = !{!"clang version 3.5.0 (211282)"}
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!6 = !{!"/tmp/asan-globals.cpp", i32 5, i32 5}
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!7 = !{!"/tmp/asan-globals.cpp", i32 7, i32 5}
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!8 = !{!"/tmp/asan-globals.cpp", i32 12, i32 14}
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!9 = !{!"/tmp/asan-globals.cpp", i32 14, i32 25}
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