[clang][rtsan] Add sanitize_realtime_unsafe attr to [[clang::blocking]] function IR (#111055)

Author: davidtrevelyan

clang/lib/CodeGen/CodeGenFunction.cpp

@@ -850,6 +850,8 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
       for (const FunctionEffectWithCondition &Fe : FD->getFunctionEffects()) {
         if (Fe.Effect.kind() == FunctionEffect::Kind::NonBlocking)
           Fn->addFnAttr(llvm::Attribute::SanitizeRealtime);
+        else if (Fe.Effect.kind() == FunctionEffect::Kind::Blocking)
+          Fn->addFnAttr(llvm::Attribute::SanitizeRealtimeUnsafe);
       }
 
   // Apply fuzzing attribute to the function.

clang/test/CodeGen/rtsan_attribute_inserted.c

@@ -1,7 +1,11 @@
 // RUN: %clang_cc1  -triple x86_64-unknown-linux -fsanitize=realtime %s -emit-llvm -o - %s | FileCheck %s
 
 float process(float *a) [[clang::nonblocking]] { return *a; }
-
-// CHECK-LABEL: @process{{.*}}#0 {
+// CHECK: @process{{.*}} #0 {
 // CHECK: attributes #0 = {
-// CHECK-SAME: {{.*sanitize_realtime.*}}
+// CHECK-SAME: {{.*sanitize_realtime .*}}
+
+int spinlock(int *a) [[clang::blocking]] { return *a; }
+// CHECK: @spinlock{{.*}} #1 {
+// CHECK: attributes #1 = {
+// CHECK-SAME: {{.*sanitize_realtime_unsafe .*}}

clang/test/CodeGen/rtsan_no_attribute_sanitizer_disabled.c

@@ -1,6 +1,8 @@
 // RUN: %clang_cc1 -triple aarch64-unknown-linux-gnu -emit-llvm -o - %s | FileCheck %s
 
 float process(float *a) [[clang::nonblocking]] { return *a; }
+int spinlock(int *a) [[clang::blocking]] { return *a; }
 
-// Without the -fsanitize=realtime flag, we shouldn't attach the attribute.
-// CHECK-NOT: {{.*sanitize_realtime.*}}
+// Without the -fsanitize=realtime flag, we shouldn't attach the attributes.
+// CHECK-NOT: {{.*sanitize_realtime .*}}
+// CHECK-NOT: {{.*sanitize_realtime_unsafe .*}}