[llvm] 7b78956 - [sanitizer] Place module_ctor/module_dtor in llvm.used
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Wed Jul 21 14:03:33 PDT 2021
Author: Fangrui Song
Date: 2021-07-21T14:03:26-07:00
New Revision: 7b789562244ee941b7bf2cefeb3fc08a59a01865
URL: https://github.com/llvm/llvm-project/commit/7b789562244ee941b7bf2cefeb3fc08a59a01865
DIFF: https://github.com/llvm/llvm-project/commit/7b789562244ee941b7bf2cefeb3fc08a59a01865.diff
LOG: [sanitizer] Place module_ctor/module_dtor in llvm.used
This removes an abuse of ELF linker behaviors while keeping Mach-O/COFF linker
behaviors unchanged.
ELF: when module_ctor is in a comdat, this patch removes reliance on a linker
abuse (an SHT_INIT_ARRAY in a section group retains the whole group) by using
SHF_GNU_RETAIN. No linker behavior difference when module_ctor is not in a comdat.
Mach-O: module_ctor gets `N_NO_DEAD_STRIP`. No linker behavior difference
because module_ctor is already referenced by a `S_MOD_INIT_FUNC_POINTERS`
section (GC root).
PE/COFF: no-op. SanitizerCoverage already appends module_ctor to `llvm.used`.
Other sanitizers: llvm.used for local linkage is not implemented in
`TargetLoweringObjectFileCOFF::emitLinkerDirectives` (once implemented or
switched to a non-local linkage, COFF can use module_ctor in comdat (i.e.
generalize ELF-specific rL301586)).
There is no object file size difference.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D106246
Added:
Modified:
llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
llvm/lib/Transforms/Utils/ModuleUtils.cpp
llvm/test/Instrumentation/AddressSanitizer/basic.ll
llvm/test/Instrumentation/AddressSanitizer/instrument_global.ll
llvm/test/Instrumentation/HWAddressSanitizer/basic.ll
llvm/test/Instrumentation/HeapProfiler/basic.ll
llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll
llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll
llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard.ll
llvm/test/Instrumentation/ThreadSanitizer/tsan_basic.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index c2ddba469dea..0f797ec13ca3 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -2138,6 +2138,8 @@ Instruction *ModuleAddressSanitizer::CreateAsanModuleDtor(Module &M) {
GlobalValue::InternalLinkage, 0, kAsanModuleDtorName, &M);
AsanDtorFunction->addAttribute(AttributeList::FunctionIndex,
Attribute::NoUnwind);
+ // Ensure Dtor cannot be discarded, even if in a comdat.
+ appendToUsed(M, {AsanDtorFunction});
BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
return ReturnInst::Create(*C, AsanDtorBB);
diff --git a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
index d8720c37305b..7607464cc0b9 100644
--- a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -384,7 +384,6 @@ Function *ModuleSanitizerCoverage::CreateInitCallsForSections(
// to include the sancov constructor. This way the linker can deduplicate
// the constructors but always leave one copy.
CtorFunc->setLinkage(GlobalValue::WeakODRLinkage);
- appendToUsed(M, CtorFunc);
}
return CtorFunc;
}
diff --git a/llvm/lib/Transforms/Utils/ModuleUtils.cpp b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
index 8c6435b52387..7c0316223cd6 100644
--- a/llvm/lib/Transforms/Utils/ModuleUtils.cpp
+++ b/llvm/lib/Transforms/Utils/ModuleUtils.cpp
@@ -128,6 +128,8 @@ Function *llvm::createSanitizerCtor(Module &M, StringRef CtorName) {
Ctor->addAttribute(AttributeList::FunctionIndex, Attribute::NoUnwind);
BasicBlock *CtorBB = BasicBlock::Create(M.getContext(), "", Ctor);
ReturnInst::Create(M.getContext(), CtorBB);
+ // Ensure Ctor cannot be discarded, even if in a comdat.
+ appendToUsed(M, {Ctor});
return Ctor;
}
diff --git a/llvm/test/Instrumentation/AddressSanitizer/basic.ll b/llvm/test/Instrumentation/AddressSanitizer/basic.ll
index 41ab493a0d1c..171eed3e2d01 100644
--- a/llvm/test/Instrumentation/AddressSanitizer/basic.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/basic.ll
@@ -8,7 +8,8 @@
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"
target triple = "x86_64-unknown-linux-gnu"
-; CHECK: @llvm.global_ctors = {{.*}}@asan.module_ctor
+; CHECK: @llvm.used = appending global [1 x i8*] [i8* bitcast (void ()* @asan.module_ctor to i8*)]
+; CHECK: @llvm.global_ctors = {{.*}}{ i32 1, void ()* @asan.module_ctor, i8* bitcast (void ()* @asan.module_ctor to i8*) }
define i32 @test_load(i32* %a) sanitize_address {
; CHECK-LABEL: @test_load
diff --git a/llvm/test/Instrumentation/AddressSanitizer/instrument_global.ll b/llvm/test/Instrumentation/AddressSanitizer/instrument_global.ll
index 18c40a503b5c..03261c542227 100644
--- a/llvm/test/Instrumentation/AddressSanitizer/instrument_global.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/instrument_global.ll
@@ -10,8 +10,9 @@ target triple = "x86_64-unknown-linux-gnu"
; module ctor/dtor
; CHECK: @___asan_gen_ = private constant [8 x i8] c"<stdin>\00", align 1
-; CHECK: llvm.global_ctors
-; CHECK: llvm.global_dtors
+; CHECK: @llvm.used = appending global [2 x i8*] [i8* bitcast (void ()* @asan.module_ctor to i8*), i8* bitcast (void ()* @asan.module_dtor to i8*)], section "llvm.metadata"
+; CHECK: @llvm.global_ctors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 1, void ()* @asan.module_ctor, i8* bitcast (void ()* @asan.module_ctor to i8*) }]
+; CHECK: @llvm.global_dtors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 1, void ()* @asan.module_dtor, i8* bitcast (void ()* @asan.module_dtor to i8*) }]
; Test that we don't instrument global arrays with static initializer
; indexed with constants in-bounds. But instrument all other cases.
diff --git a/llvm/test/Instrumentation/HWAddressSanitizer/basic.ll b/llvm/test/Instrumentation/HWAddressSanitizer/basic.ll
index 7307ca200e27..04f0a381c3a2 100644
--- a/llvm/test/Instrumentation/HWAddressSanitizer/basic.ll
+++ b/llvm/test/Instrumentation/HWAddressSanitizer/basic.ll
@@ -11,6 +11,7 @@
; RUN: opt < %s -passes=hwasan -hwasan-recover=0 -hwasan-mapping-offset=0 -S | FileCheck %s --check-prefixes=CHECK,ABORT
; RUN: opt < %s -passes=hwasan -hwasan-recover=1 -hwasan-mapping-offset=0 -S | FileCheck %s --check-prefixes=CHECK,RECOVER,RECOVER-ZERO-BASED-SHADOW
+; CHECK: @llvm.used = appending global [1 x i8*] [i8* bitcast (void ()* @hwasan.module_ctor to i8*)]
; CHECK: @llvm.global_ctors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 0, void ()* @hwasan.module_ctor, i8* bitcast (void ()* @hwasan.module_ctor to i8*) }]
target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
diff --git a/llvm/test/Instrumentation/HeapProfiler/basic.ll b/llvm/test/Instrumentation/HeapProfiler/basic.ll
index cf6320414bd3..45124d4eb3aa 100644
--- a/llvm/test/Instrumentation/HeapProfiler/basic.ll
+++ b/llvm/test/Instrumentation/HeapProfiler/basic.ll
@@ -9,7 +9,9 @@
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"
target triple = "x86_64-unknown-linux-gnu"
-; CHECK: @llvm.global_ctors = {{.*}}@memprof.module_ctor
+
+; CHECK: @llvm.used = appending global [1 x i8*] [i8* bitcast (void ()* @memprof.module_ctor to i8*)]
+; CHECK: @llvm.global_ctors = appending global [1 x { i32, void ()*, i8* }] [{ i32, void ()*, i8* } { i32 1, void ()* @memprof.module_ctor, i8* null }]
define i32 @test_load(i32* %a) {
entry:
diff --git a/llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll b/llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll
index e9afb0febe3f..82135644c6bf 100644
--- a/llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll
+++ b/llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll
@@ -10,6 +10,7 @@
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-S128"
target triple = "x86_64-unknown-linux-gnu"
+; CHECK: @llvm.used = appending global [1 x i8*] [i8* bitcast (void ()* @msan.module_ctor to i8*)]
; CHECK: @llvm.global_ctors {{.*}} { i32 0, void ()* @msan.module_ctor, i8* null }
; Check the presence and the linkage type of __msan_track_origins and
diff --git a/llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll b/llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll
index 42951f1f09c0..3acfe43ac748 100644
--- a/llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll
+++ b/llvm/test/Instrumentation/SanitizerCoverage/inline-bool-flag.ll
@@ -6,7 +6,7 @@
; CHECK: @__sancov_gen_ = private global [1 x i1] zeroinitializer, section "__sancov_bools", comdat($foo), align 1{{$}}
; CHECK: @__start___sancov_bools = extern_weak hidden global i1
; CHECK-NEXT: @__stop___sancov_bools = extern_weak hidden global i1
-; CHECK-NOT: @llvm.used =
+; CHECK: @llvm.used = appending global [1 x i8*] [i8* bitcast (void ()* @sancov.module_ctor_bool_flag to i8*)], section "llvm.metadata"
; CHECK: @llvm.compiler.used = appending global [1 x i8*] [i8* bitcast ([1 x i1]* @__sancov_gen_ to i8*)], section "llvm.metadata"
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"
diff --git a/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard.ll b/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard.ll
index 5df7f31c91fa..0b4a0ef821b2 100644
--- a/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard.ll
+++ b/llvm/test/Instrumentation/SanitizerCoverage/trace-pc-guard.ll
@@ -18,9 +18,9 @@
; WIN: @__sancov_gen_ = private global [3 x i32] zeroinitializer, section ".SCOV$GM", comdat($foo), align 4{{$}}
; WIN-NEXT: @__sancov_gen_.1 = private global [1 x i32] zeroinitializer, section ".SCOV$GM", comdat($CallViaVptr), align 4{{$}}
-; ELF-NOT: @llvm.used =
+; ELF: @llvm.used = appending global [1 x i8*] [i8* bitcast (void ()* @sancov.module_ctor_trace_pc_guard to i8*)]
; ELF: @llvm.compiler.used = appending global [2 x i8*] [i8* bitcast ([3 x i32]* @__sancov_gen_ to i8*), i8* bitcast ([1 x i32]* @__sancov_gen_.1 to i8*)], section "llvm.metadata"
-; MACHO: @llvm.used = appending global [2 x i8*] [i8* bitcast ([3 x i32]* @__sancov_gen_ to i8*), i8* bitcast ([1 x i32]* @__sancov_gen_.1 to i8*)], section "llvm.metadata"
+; MACHO: @llvm.used = appending global [3 x i8*] [i8* bitcast (void ()* @sancov.module_ctor_trace_pc_guard to i8*), i8* bitcast ([3 x i32]* @__sancov_gen_ to i8*), i8* bitcast ([1 x i32]* @__sancov_gen_.1 to i8*)]
; MACHO-NOT: @llvm.compiler.used =
; WIN: @llvm.used = appending global [1 x i8*] [i8* bitcast (void ()* @sancov.module_ctor_trace_pc_guard to i8*)], section "llvm.metadata"
; WIN-NEXT: @llvm.compiler.used = appending global [2 x i8*] [i8* bitcast ([3 x i32]* @__sancov_gen_ to i8*), i8* bitcast ([1 x i32]* @__sancov_gen_.1 to i8*)], section "llvm.metadata"
diff --git a/llvm/test/Instrumentation/ThreadSanitizer/tsan_basic.ll b/llvm/test/Instrumentation/ThreadSanitizer/tsan_basic.ll
index 20406c7f147c..db559f6987e5 100644
--- a/llvm/test/Instrumentation/ThreadSanitizer/tsan_basic.ll
+++ b/llvm/test/Instrumentation/ThreadSanitizer/tsan_basic.ll
@@ -10,6 +10,7 @@ entry:
ret i32 %tmp1
}
+; CHECK: @llvm.used = appending global [1 x i8*] [i8* bitcast (void ()* @tsan.module_ctor to i8*)]
; CHECK: @llvm.global_ctors = {{.*}}@tsan.module_ctor
; CHECK: define i32 @read_4_bytes(i32* %a)
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