[sanitizer] Delay sanitizer args parsing (#107280)

Delay sanitizer arg parsing until after -Xclang flags are forwarded to
the clang command line. This allows the check in hasTargetFeatureMTE to
pick up manually specified target feature, and enables the following:
  -march=armv8-a -Xclang -target-feature -Xclang +mte
  -fsanitize=memtag-stack

Author: eugenis

clang/lib/Driver/ToolChains/Clang.cpp

@@ -6786,8 +6786,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("--offload-new-driver");
   }
 
-  SanitizeArgs.addArgs(TC, Args, CmdArgs, InputType);
-
   const XRayArgs &XRay = TC.getXRayArgs();
   XRay.addArgs(TC, Args, CmdArgs, InputType);
 
@@ -7677,6 +7675,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     }
   }
 
+  // This needs to run after -Xclang argument forwarding to pick up the target
+  // features enabled through -Xclang -target-feature flags.
+  SanitizeArgs.addArgs(TC, Args, CmdArgs, InputType);
+
   // With -save-temps, we want to save the unoptimized bitcode output from the
   // CompileJobAction, use -disable-llvm-passes to get pristine IR generated
   // by the frontend.

clang/test/Driver/fsanitize.c

@@ -197,6 +197,8 @@
 // CHECK-SANMT-MT: "-target-feature" "+mte"
 // CHECK-SANMT-MT-SAME: "-fsanitize=memtag-stack,memtag-heap,memtag-globals"
 
+// RUN: not %clang --target=aarch64-linux -fsanitize=memtag -Xclang -target-feature -Xclang +mte %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANMT-MT
+
 // RUN: not %clang --target=aarch64-linux -fsanitize=memtag %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-SANMT-NOMT-0
 // CHECK-SANMT-NOMT-0: '-fsanitize=memtag-stack' requires hardware support (+memtag)
 
@@ -726,8 +728,8 @@
 // NO-SP-NOT: stack-protector
 // NO-SP: "-fsanitize=safe-stack"
 // SP-ASAN: error: invalid argument '-fsanitize=safe-stack' not allowed with '-fsanitize=address'
-// SP: "-fsanitize=safe-stack"
 // SP: -stack-protector
+// SP: "-fsanitize=safe-stack"
 // NO-SP-NOT: stack-protector
 
 // RUN: %clang --target=powerpc64-unknown-linux-gnu -fsanitize=memory %s -### 2>&1 | FileCheck %s -check-prefix=CHECK-SANM

clang/test/Driver/fuchsia.c

@@ -30,10 +30,10 @@
 // CHECK: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
 // CHECK: "-isysroot" "[[SYSROOT:[^"]+]]"
 // CHECK: "-internal-externc-isystem" "[[SYSROOT]]{{/|\\\\}}include"
+// CHECK: "-stack-protector" "2"
 // CHECK-AARCH64: "-fsanitize=shadow-call-stack"
 // CHECK-RISCV64: "-fsanitize=shadow-call-stack"
 // CHECK-X86_64: "-fsanitize=safe-stack"
-// CHECK: "-stack-protector" "2"
 // CHECK-AARCH64: "-target-feature" "+outline-atomics"
 // CHECK-NOT: "-fcommon"
 // CHECK: {{.*}}ld.lld{{.*}}" "-z" "max-page-size=4096" "-z" "now" "-z" "start-stop-visibility=hidden" "-z" "rodynamic" "-z" "separate-loadable-segments" "-z" "rel" "--pack-dyn-relocs=relr"