[Clang][Driver] Add KCFI to SupportsCoverage

[samitolvanen]

Summary

Allow -fsanitize=kcfi to be enabled with -fsanitize-coverage= modes
such as trace-{pc,cmp}.

Link: https://github.com/ClangBuiltLinux/linux/issues/1743

[MaskRay]

with -fsanitize=trace-{pc,cmp}.

-fsanitize-coverage= modes such as trace-{pc,cmp}.

(a) It's -fsanitize-coverage=, not -fsanitize-coverage=trace-{pc,cmp}.
(b) -fsanitize=trace-{pc,cmp} may feel that they are the only modes, but SanitizerCoverage has much more modes than the mentioned two.

clang/test/CodeGen/sanitize-coverage.c

92

One call void @__sanitizer_cov_trace is probably sufficient.

94

%c()

{{.}} matches one byte. Just write the byte.

[samitolvanen]

Addressed feedback.

clang/test/CodeGen/sanitize-coverage.c

94

%c()

{{.}} matches one byte. Just write the byte.

I do want to match just one byte, but the actual byte changes depending on how many statements there are in the function, so matching any byte seems less fragile. %c would match literally just %c. Am I missing some neat FileCheck trick here that would save me a ton of typing in future...?

[MaskRay]

clang/test/CodeGen/sanitize-coverage.c

94

Ah, ok, it's an unnamed value. [[#]] can match %1 %2 ...

[samitolvanen]

Switched to [[#]].

clang/lib/Driver/SanitizerArgs.cpp

static const SanitizerMask SupportsCoverage =
     SanitizerKind::MemtagStack | SanitizerKind::MemtagHeap |
     SanitizerKind::MemtagGlobals | SanitizerKind::Memory |
     SanitizerKind::KernelMemory | SanitizerKind::Leak |
     SanitizerKind::Undefined | SanitizerKind::Integer | SanitizerKind::Bounds |
     SanitizerKind::ImplicitConversion | SanitizerKind::Nullability |
     SanitizerKind::DataFlow | SanitizerKind::Fuzzer |
     SanitizerKind::FuzzerNoLink | SanitizerKind::FloatDivideByZero |
     SanitizerKind::SafeStack | SanitizerKind::ShadowCallStack |
-    SanitizerKind::Thread | SanitizerKind::ObjCCast;
+    SanitizerKind::Thread | SanitizerKind::ObjCCast | SanitizerKind::KCFI;
 static const SanitizerMask RecoverableByDefault =
     SanitizerKind::Undefined | SanitizerKind::Integer |
     SanitizerKind::ImplicitConversion | SanitizerKind::Nullability |
     SanitizerKind::FloatDivideByZero | SanitizerKind::ObjCCast;
 static const SanitizerMask Unrecoverable =
     SanitizerKind::Unreachable | SanitizerKind::Return;
 static const SanitizerMask AlwaysRecoverable = SanitizerKind::KernelAddress |
                                                SanitizerKind::KernelHWAddress |

clang/test/CodeGen/sanitize-coverage.c

 // RUN: %clang %s -target x86_64-unknown-linux-gnu -emit-llvm -S                       -fsanitize-coverage=trace-pc,trace-cmp -o - | FileCheck %s --check-prefixes=CHECK
 // RUN: %clang %s -target x86_64-unknown-linux-gnu -emit-llvm -S -fsanitize=address    -fsanitize-coverage=trace-pc,trace-cmp -o - | FileCheck %s --check-prefixes=CHECK,ASAN
 // RUN: %clang %s -target x86_64-unknown-linux-gnu -emit-llvm -S -fsanitize=bounds     -fsanitize-coverage=trace-pc,trace-cmp -o - | FileCheck %s --check-prefixes=CHECK,BOUNDS
 // RUN: %clang %s -target x86_64-unknown-linux-gnu -emit-llvm -S -fsanitize=memory     -fsanitize-coverage=trace-pc,trace-cmp -o - | FileCheck %s --check-prefixes=CHECK,MSAN
 // RUN: %clang %s -target x86_64-unknown-linux-gnu -emit-llvm -S -fsanitize=thread     -fsanitize-coverage=trace-pc,trace-cmp -o - | FileCheck %s --check-prefixes=CHECK,TSAN
 // RUN: %clang %s -target x86_64-unknown-linux-gnu -emit-llvm -S -fsanitize=undefined  -fsanitize-coverage=trace-pc,trace-cmp -o - | FileCheck %s --check-prefixes=CHECK,UBSAN
+// RUN: %clang %s -target x86_64-unknown-linux-gnu -emit-llvm -S -fsanitize=kcfi       -fsanitize-coverage=trace-pc,trace-cmp -o - | FileCheck %s --check-prefixes=CHECK,KCFI
 
 int x[10];
+extern void (*f)(void);
 
 // CHECK-LABEL: define dso_local void @foo(
 void foo(int n) {
   // CHECK-DAG: call void @__sanitizer_cov_trace_pc
   // CHECK-DAG: call void @__sanitizer_cov_trace_const_cmp
   // ASAN-DAG: call void @__asan_report_store
   // MSAN-DAG: call void @__msan_warning
   // BOUNDS-DAG: call void @__ubsan_handle_out_of_bounds
   // TSAN-DAG: call void @__tsan_func_entry
   // UBSAN-DAG: call void @__ubsan_handle
   if (n)
     x[n] = 42;
+  // KCFI-DAG: call void %[[#]]() [ "kcfi"(i32 {{.*}}) ]
+  f();
 }
 
 static inline __attribute__((__always_inline__)) void always_inlined_fn(int n) {
   if (n)
     x[n] = 42;
 }
 // CHECK-LABEL: define dso_local void @test_always_inline(
 void test_always_inline(int n) {
   // CHECK-DAG: call void @__sanitizer_cov_trace_pc
   // CHECK-DAG: call void @__sanitizer_cov_trace_const_cmp
   always_inlined_fn(n);
 }
 
 // CHECK-LABEL: define dso_local void @test_no_sanitize_coverage(
 __attribute__((no_sanitize("coverage"))) void test_no_sanitize_coverage(int n) {
   // CHECK-NOT: call void @__sanitizer_cov_trace_pc
   // CHECK-NOT: call void @__sanitizer_cov_trace_const_cmp
   // ASAN-DAG: call void @__asan_report_store
   // MSAN-DAG: call void @__msan_warning
   // BOUNDS-DAG: call void @__ubsan_handle_out_of_bounds
   // TSAN-DAG: call void @__tsan_func_entry
   // UBSAN-DAG: call void @__ubsan_handle
   if (n)
     x[n] = 42;
+  // KCFI-DAG: call void %[[#]]() [ "kcfi"(i32 {{.*}}) ]
+  f();
 }
 
 
 // CHECK-LABEL: define dso_local void @test_no_sanitize_combined(
 __attribute__((no_sanitize("address", "memory", "thread", "bounds", "undefined", "coverage")))
 void test_no_sanitize_combined(int n) {
   // CHECK-NOT: call void @__sanitizer_cov_trace_pc
   // CHECK-NOT: call void @__sanitizer_cov_trace_const_cmp
void test_no_sanitize_separate(int n) {
   // BOUNDS-NOT: call void @__ubsan_handle_out_of_bounds
   // BOUNDS-NOT: call void @llvm.trap()
   // TSAN-NOT: call void @__tsan_func_entry
   // UBSAN-NOT: call void @__ubsan_handle
   if (n)
     x[n] = 42;
 }
 
+// CHECK-LABEL: define dso_local void @test_no_sanitize_kcfi(
+__attribute__((no_sanitize("kcfi", "coverage")))
+void test_no_sanitize_kcfi(void) {
+  // CHECK-NOT: call void @__sanitizer_cov_trace
+  // KCFI-NOT: call void %[[#]]() [ "kcfi"(i32 {{.*}}) ]
+  f();
+}
+
 // CHECK-LABEL: define dso_local void @test_no_sanitize_always_inline(
 __attribute__((no_sanitize("coverage")))
 void test_no_sanitize_always_inline(int n) {
   // CHECK-NOT: call void @__sanitizer_cov_trace_pc
   // CHECK-NOT: call void @__sanitizer_cov_trace_const_cmp
   always_inlined_fn(n);
 }
 
 // CHECK-LABEL: declare void

clang/test/Driver/fsanitize-coverage.c

 // RUN: %clang -target x86_64-linux-gnu -fsanitize=memory -fsanitize-coverage=func,trace-pc %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-FUNC
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=kernel-memory -fsanitize-coverage=func,trace-pc %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-FUNC
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=leak -fsanitize-coverage=func,trace-pc %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-FUNC
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=undefined -fsanitize-coverage=func,trace-pc %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-FUNC
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=bounds -fsanitize-coverage=func,trace-pc %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-FUNC
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=bool -fsanitize-coverage=func,trace-pc %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-FUNC
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=dataflow -fsanitize-coverage=func,trace-pc %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-FUNC
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=thread -fsanitize-coverage=func,trace-pc %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-FUNC
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=kcfi -fsanitize-coverage=func,trace-pc %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-FUNC
 // RUN: %clang -target %itanium_abi_triple -fsanitize=float-divide-by-zero -fsanitize-coverage=func,trace-pc %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-FUNC
 // RUN: %clang -target x86_64-linux-gnu                     -fsanitize-coverage=func,trace-pc %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-FUNC
 // CHECK-SANITIZE-COVERAGE-FUNC: fsanitize-coverage-type=1
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-coverage=bb %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-BB
 // CHECK-SANITIZE-COVERAGE-BB: fsanitize-coverage-type=2
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-coverage=edge %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANITIZE-COVERAGE-EDGE