1 // RUN: %clang -target x86_64-linux-gnu -S -emit-llvm -o - %s | FileCheck -check-prefixes CHECK,WITHOUT %s 2 // RUN: %clang -target x86_64-linux-gnu -S -emit-llvm -o - %s -fsanitize=memory | FileCheck -check-prefixes CHECK,MSAN %s 3 // RUN: %clang -target x86_64-linux-gnu -S -emit-llvm -o - %s -fsanitize=kernel-memory | FileCheck -check-prefixes CHECK,KMSAN %s 4 5 // Instrumented function. 6 // MSan uses memset(addr, -1, size) to poison allocas and stores shadow of the return value in 7 // __msan_retval_tls. KMSAN uses __msan_poison_alloca() to poison allocas and calls 8 // __msan_get_context_state() at function prologue to access the task context struct (including the 9 // shadow of the return value). 10 // 11 // CHECK-LABEL: i32 @instrumented1 12 // KMSAN: __msan_get_context_state 13 // WITHOUT-NOT: __msan_poison_alloca 14 // WITHOUT-NOT: @llvm.memset 15 // MSAN: @llvm.memset{{.*}}({{.*}}, i8 -1 16 // KMSAN: __msan_poison_alloca 17 // WITHOUT-NOT: __msan_retval_tls 18 // MSAN: __msan_retval_tls 19 // CHECK: ret i32 20 int instrumented1(int *a) { 21 volatile char buf[8]; 22 return *a; 23 } 24 25 // Function with no_sanitize("memory")/no_sanitize("kernel-memory"): no shadow propagation, but 26 // unpoisons memory to prevent false positives. 27 // MSan uses memset(addr, 0, size) to unpoison locals, KMSAN uses __msan_unpoison_alloca(). Both 28 // tools still access the retval shadow to write 0 to it. 29 // 30 // CHECK-LABEL: i32 @no_false_positives1 31 // KMSAN: __msan_get_context_state 32 // WITHOUT-NOT: __msan_unpoison_alloca 33 // WITHOUT-NOT: @llvm.memset 34 // MSAN: @llvm.memset{{.*}}({{.*}}, i8 0 35 // KMSAN: __msan_unpoison_alloca 36 // WITHOUT-NOT: __msan_retval_tls 37 // MSAN: __msan_retval_tls 38 // CHECK: ret i32 39 __attribute__((no_sanitize("memory"))) __attribute__((no_sanitize("kernel-memory"))) int no_false_positives1(int *a) { 40 volatile char buf[8]; 41 return *a; 42 } 43 44 // Function with disable_sanitizer_instrumentation: no instrumentation at all. 45 // 46 // CHECK-LABEL: i32 @no_instrumentation1 47 // KMSAN-NOT: __msan_get_context_state 48 // WITHOUT-NOT: __msan_poison_alloca 49 // WITHOUT-NOT: @llvm.memset 50 // MSAN-NOT: @llvm.memset{{.*}}({{.*}}, i8 0 51 // KMSAN-NOT: __msan_unpoison_alloca 52 // WITHOUT-NOT: __msan_retval_tls 53 // MSAN-NOT: __msan_retval_tls 54 // CHECK: ret i32 55 __attribute__((disable_sanitizer_instrumentation)) int no_instrumentation1(int *a) { 56 volatile char buf[8]; 57 return *a; 58 } 59