1 // RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -emit-llvm -fextend-variable-liveness -fsanitize=null -fsanitize-trap=null -o - | FileCheck --check-prefixes=CHECK,NULL --implicit-check-not=ubsantrap %s 2 // RUN: %clang_cc1 %s -triple x86_64-unknown-linux-gnu -emit-llvm -fextend-variable-liveness -o - | FileCheck %s 3 4 // With -fextend-variable-liveness, the compiler previously generated a fake.use of any 5 // reference variable at the end of the scope in which its alloca exists. This 6 // caused two issues, where we would get fake uses for uninitialized variables 7 // if that variable was declared after an early-return, and UBSan's null checks 8 // would complain about this. 9 // This test verifies that UBSan does not produce null-checks for arguments to 10 // llvm.fake.use, and that fake uses are not emitted for a variable on paths 11 // it has not been declared. 12 13 struct A { short s1, s2; }; 14 extern long& getA(); 15 16 void foo() 17 { 18 auto& va = getA(); 19 if (va < 5) 20 return; 21 22 auto& vb = getA(); 23 } 24 25 // CHECK-LABEL: define{{.*}}foo 26 // CHECK: [[VA_CALL:%.+]] = call{{.*}} ptr @_Z4getAv() 27 28 /// We check here for the first UBSan check for "va". 29 // NULL: [[VA_ISNULL:%.+]] = icmp ne ptr [[VA_CALL]], null 30 // NULL: br i1 [[VA_ISNULL]], label %{{[^,]+}}, label %[[VA_TRAP:[^,]+]] 31 // NULL: [[VA_TRAP]]: 32 // NULL: call void @llvm.ubsantrap( 33 34 // CHECK: [[VA_PTR:%.+]] = load ptr, ptr %va 35 // CHECK-NEXT: [[VA_CMP:%.+]] = load i64, ptr [[VA_PTR]] 36 // CHECK-NEXT: [[VA_CMP_RES:%.+]] = icmp slt i64 [[VA_CMP]], 5 37 // CHECK-NEXT: br i1 [[VA_CMP_RES]], label %[[EARLY_EXIT:[^,]+]], label %[[NOT_EARLY_EXIT:[^,]+]] 38 39 // CHECK: [[EARLY_EXIT]]: 40 // CHECK: br label %cleanup 41 42 /// The fake use for "vb" only appears on the path where its declaration is 43 /// reached. 44 // CHECK: [[NOT_EARLY_EXIT]]: 45 // CHECK: [[VB_CALL:%.+]] = call{{.*}} ptr @_Z4getAv() 46 47 /// We check here for the second UBSan check for "vb". 48 // NULL: [[VB_ISNULL:%.+]] = icmp ne ptr [[VB_CALL]], null 49 // NULL: br i1 [[VB_ISNULL]], label %{{[^,]+}}, label %[[VB_TRAP:[^,]+]] 50 // NULL: [[VB_TRAP]]: 51 // NULL: call void @llvm.ubsantrap( 52 53 // CHECK: [[VB_FAKE_USE:%.+]] = load ptr, ptr %vb 54 // CHECK-NEXT: call void (...) @llvm.fake.use(ptr [[VB_FAKE_USE]]) 55 // CHECK: br label %cleanup 56 57 // CHECK: cleanup: 58 // CHECK: [[VA_FAKE_USE:%.+]] = load ptr, ptr %va 59 // CHECK-NEXT: call void (...) @llvm.fake.use(ptr [[VA_FAKE_USE]]) 60 61 // NULL: declare void @llvm.ubsantrap 62