[ASAN] Use nosanitize module flag.

Author: skc7

llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp

@@ -1249,17 +1249,11 @@ AddressSanitizerPass::AddressSanitizerPass(
       UseOdrIndicator(UseOdrIndicator), DestructorKind(DestructorKind),
       ConstructorKind(ConstructorKind) {}
 
-static bool hasAsanModuleCtor(Module &M) {
-  if (M.getFunction(kAsanModuleCtorName))
-    return true;
-  return false;
-}
-
 PreservedAnalyses AddressSanitizerPass::run(Module &M,
                                             ModuleAnalysisManager &MAM) {
-  // Return early if asan.module_ctor is already present in the module.
+  // Return early if nosanitize module flag is present for the module.
   // This implies that asan pass has already run before.
-  if (hasAsanModuleCtor(M))
+  if (M.getModuleFlag("nosanitize"))
     return PreservedAnalyses::all();
 
   ModuleAddressSanitizer ModuleSanitizer(
@@ -1278,6 +1272,8 @@ PreservedAnalyses AddressSanitizerPass::run(Module &M,
     Modified |= FunctionSanitizer.instrumentFunction(F, &TLI);
   }
   Modified |= ModuleSanitizer.instrumentModule(M);
+  if (Modified)
+    M.addModuleFlag(Module::ModFlagBehavior::Override, "nosanitize", 1);
   if (!Modified)
     return PreservedAnalyses::all();
 

llvm/test/Instrumentation/AddressSanitizer/asan-pass-second-run.ll

@@ -1,4 +1,4 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals all --version 5
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-attributes --check-globals all --version 5
 ; This test checks in the second run, function is not instrumented again.
 ; RUN: opt < %s -passes=asan,asan -S | FileCheck %s
 
@@ -8,13 +8,12 @@ target triple = "x86_64-unknown-linux-gnu"
 ; Function with sanitize_address is instrumented.
 ; Function Attrs: nounwind uwtable
 ;.
-; CHECK: @llvm.used = appending global [1 x ptr] [ptr @asan.module_ctor], section "llvm.metadata"
 ; CHECK: @___asan_globals_registered = common hidden global i64 0
 ; CHECK: @__start_asan_globals = extern_weak hidden global i64
 ; CHECK: @__stop_asan_globals = extern_weak hidden global i64
-; CHECK: @llvm.global_ctors = appending global [1 x { i32, ptr, ptr }] [{ i32, ptr, ptr } { i32 1, ptr @asan.module_ctor, ptr @asan.module_ctor }]
 ;.
 define void @instr_sa(ptr %a) sanitize_address {
+; CHECK: Function Attrs: sanitize_address
 ; CHECK-LABEL: define void @instr_sa(
 ; CHECK-SAME: ptr [[A:%.*]]) #[[ATTR0:[0-9]+]] {
 ; CHECK-NEXT:  [[ENTRY:.*:]]
@@ -24,15 +23,15 @@ define void @instr_sa(ptr %a) sanitize_address {
 ; CHECK-NEXT:    [[TMP3:%.*]] = inttoptr i64 [[TMP2]] to ptr
 ; CHECK-NEXT:    [[TMP4:%.*]] = load i8, ptr [[TMP3]], align 1
 ; CHECK-NEXT:    [[TMP5:%.*]] = icmp ne i8 [[TMP4]], 0
-; CHECK-NEXT:    br i1 [[TMP5]], label %[[BB6:.*]], label %[[BB12:.*]], !prof [[PROF0:![0-9]+]]
+; CHECK-NEXT:    br i1 [[TMP5]], label %[[BB6:.*]], label %[[BB12:.*]], !prof [[PROF1:![0-9]+]]
 ; CHECK:       [[BB6]]:
 ; CHECK-NEXT:    [[TMP7:%.*]] = and i64 [[TMP0]], 7
 ; CHECK-NEXT:    [[TMP8:%.*]] = add i64 [[TMP7]], 3
 ; CHECK-NEXT:    [[TMP9:%.*]] = trunc i64 [[TMP8]] to i8
 ; CHECK-NEXT:    [[TMP10:%.*]] = icmp sge i8 [[TMP9]], [[TMP4]]
 ; CHECK-NEXT:    br i1 [[TMP10]], label %[[BB11:.*]], label %[[BB12]]
 ; CHECK:       [[BB11]]:
-; CHECK-NEXT:    call void @__asan_report_load4(i64 [[TMP0]]) #[[ATTR3:[0-9]+]]
+; CHECK-NEXT:    call void @__asan_report_load4(i64 [[TMP0]]) #[[ATTR2:[0-9]+]]
 ; CHECK-NEXT:    unreachable
 ; CHECK:       [[BB12]]:
 ; CHECK-NEXT:    [[TMP1:%.*]] = load i32, ptr [[A]], align 4
@@ -49,8 +48,8 @@ entry:
 ;.
 ; CHECK: attributes #[[ATTR0]] = { sanitize_address }
 ; CHECK: attributes #[[ATTR1:[0-9]+]] = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
-; CHECK: attributes #[[ATTR2:[0-9]+]] = { nounwind }
-; CHECK: attributes #[[ATTR3]] = { nomerge }
+; CHECK: attributes #[[ATTR2]] = { nomerge }
 ;.
-; CHECK: [[PROF0]] = !{!"branch_weights", i32 1, i32 1048575}
+; CHECK: [[META0:![0-9]+]] = !{i32 4, !"nosanitize", i32 1}
+; CHECK: [[PROF1]] = !{!"branch_weights", i32 1, i32 1048575}
 ;.

llvm/test/Instrumentation/AddressSanitizer/missing_dbg.ll

@@ -34,4 +34,4 @@ entry:
 !4 = !DISubroutineType(types: !5)
 !5 = !{}
 
-; CHECK:       [[DBG]] = !DILocation(line: 0, scope: !3)
+; CHECK:       [[DBG]] = !DILocation(line: 0, scope: !4)