[sanitizer] Allow use-after-scope front-end argument to take effect with -fsanitize=kernel-address (#137015)

Allow `-f[no]-sanitize-address-use-after-scope` to take effect under
kernel-address sanitizer (`-fsanitize=kernel-address`). `use-after-scope` is
now enabled by default under kernel-address sanitizer.

Previously, users may have enabled `use-after-scope` checks for kernel-address
sanitizer via `-mllvm -asan-use-after-scope=true`. While this may have worked
for optimization levels > O0, the required lifetime intrinsics to allow for
`use-after-scope` detection were not emitted under O0. This commit ensures
the required lifetime intrinsics are emitted under O0 with kernel-address
sanitizer.

Author: dgg5503

clang/lib/Driver/SanitizerArgs.cpp

@@ -1028,10 +1028,6 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
     StableABI = Args.hasFlag(options::OPT_fsanitize_stable_abi,
                              options::OPT_fno_sanitize_stable_abi, false);
 
-    AsanUseAfterScope = Args.hasFlag(
-        options::OPT_fsanitize_address_use_after_scope,
-        options::OPT_fno_sanitize_address_use_after_scope, AsanUseAfterScope);
-
     AsanPoisonCustomArrayCookie = Args.hasFlag(
         options::OPT_fsanitize_address_poison_custom_array_cookie,
         options::OPT_fno_sanitize_address_poison_custom_array_cookie,
@@ -1093,7 +1089,6 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
     }
 
   } else {
-    AsanUseAfterScope = false;
     // -fsanitize=pointer-compare/pointer-subtract requires -fsanitize=address.
     SanitizerMask DetectInvalidPointerPairs =
         SanitizerKind::PointerCompare | SanitizerKind::PointerSubtract;
@@ -1107,6 +1102,14 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
     }
   }
 
+  if (AllAddedKinds & (SanitizerKind::Address | SanitizerKind::KernelAddress)) {
+    AsanUseAfterScope = Args.hasFlag(
+        options::OPT_fsanitize_address_use_after_scope,
+        options::OPT_fno_sanitize_address_use_after_scope, AsanUseAfterScope);
+  } else {
+    AsanUseAfterScope = false;
+  }
+
   if (AllAddedKinds & SanitizerKind::HWAddress) {
     if (Arg *HwasanAbiArg =
             Args.getLastArg(options::OPT_fsanitize_hwaddress_abi_EQ)) {

clang/test/CodeGen/lifetime-sanitizer.c

@@ -4,6 +4,9 @@
 // RUN:     -fsanitize=address -fsanitize-address-use-after-scope \
 // RUN:     -Xclang -disable-llvm-passes %s | FileCheck %s -check-prefix=LIFETIME
 // RUN: %clang -target x86_64-linux-gnu -S -emit-llvm -o - -O0 \
+// RUN:     -fsanitize=kernel-address -fsanitize-address-use-after-scope \
+// RUN:     -Xclang -disable-llvm-passes %s | FileCheck %s -check-prefix=LIFETIME
+// RUN: %clang -target x86_64-linux-gnu -S -emit-llvm -o - -O0 \
 // RUN:     -fsanitize=memory -Xclang -disable-llvm-passes %s | \
 // RUN:     FileCheck %s -check-prefix=LIFETIME
 // RUN: %clang -target aarch64-linux-gnu -S -emit-llvm -o - -O0 \

clang/test/CodeGenCXX/lifetime-sanitizer.cpp

@@ -5,6 +5,9 @@
 // RUN:     -fsanitize=address -fsanitize-address-use-after-scope \
 // RUN:     -Xclang -disable-llvm-passes %s | FileCheck %s -check-prefixes=CHECK,LIFETIME
 // RUN: %clang -w -target x86_64-linux-gnu -S -emit-llvm -o - -fno-exceptions -O0 \
+// RUN:     -fsanitize=kernel-address -fsanitize-address-use-after-scope \
+// RUN:     -Xclang -disable-llvm-passes %s | FileCheck %s -check-prefixes=CHECK,LIFETIME
+// RUN: %clang -w -target x86_64-linux-gnu -S -emit-llvm -o - -fno-exceptions -O0 \
 // RUN:     -fsanitize=memory -Xclang -disable-llvm-passes %s | \
 // RUN:     FileCheck %s -check-prefixes=CHECK,LIFETIME
 // RUN: %clang -w -target aarch64-linux-gnu -S -emit-llvm -o - -fno-exceptions -O0 \