[MSan] Add flag to disable use-after-dtor.

[morehouse]

Summary

Flag is -fno-sanitize-use-after-dtor.

[morehouse]

• Use hasFlag() in CompilerInvocation.cpp as well.

[vitalybuka]

clang/lib/Driver/SanitizerArgs.cpp

494

false -> MsanUseAfterDtor

[eugenis]

Have you looked at performance?

[vitalybuka]

In D37867#871353, @eugenis wrote:

Have you looked at performance?

Not the answer to your question, but this patch just adds negative flag without changing defaults.

[eugenis]

Oh right, I was looking at D37860.

clang/include/clang/Driver/Options.td

def fsanitize_memory_track_origins : Flag<["-"], "fsanitize-memory-track-origins">,
                                      HelpText<"Enable origins tracking in MemorySanitizer">;
 def fno_sanitize_memory_track_origins : Flag<["-"], "fno-sanitize-memory-track-origins">,
                                         Group<f_clang_Group>,
                                         Flags<[CoreOption, DriverOption]>,
                                         HelpText<"Disable origins tracking in MemorySanitizer">;
 def fsanitize_memory_use_after_dtor : Flag<["-"], "fsanitize-memory-use-after-dtor">,
                                      Group<f_clang_Group>,
                                      HelpText<"Enable use-after-destroy detection in MemorySanitizer">;
+def fno_sanitize_memory_use_after_dtor : Flag<["-"], "fno-sanitize-memory-use-after-dtor">,
+                                     Group<f_clang_Group>,
+                                     HelpText<"Disable use-after-destroy detection in MemorySanitizer">;
 def fsanitize_address_field_padding : Joined<["-"], "fsanitize-address-field-padding=">,
                                         Group<f_clang_Group>,
                                         HelpText<"Level of field padding for AddressSanitizer">;
 def fsanitize_address_use_after_scope : Flag<["-"], "fsanitize-address-use-after-scope">,
                                         Group<f_clang_Group>,
                                         HelpText<"Enable use-after-scope detection in AddressSanitizer">;
 def fno_sanitize_address_use_after_scope : Flag<["-"], "fno-sanitize-address-use-after-scope">,
                                            Group<f_clang_Group>,

clang/lib/Driver/SanitizerArgs.cpp

if (Arg *A =
         StringRef S = A->getValue();
         if (S.getAsInteger(0, MsanTrackOrigins) || MsanTrackOrigins < 0 ||
             MsanTrackOrigins > 2) {
           D.Diag(clang::diag::err_drv_invalid_value) << A->getAsString(Args) << S;
         }
       }
     }
     MsanUseAfterDtor =
-        Args.hasArg(options::OPT_fsanitize_memory_use_after_dtor);
+        Args.hasFlag(options::OPT_fsanitize_memory_use_after_dtor,
+                     options::OPT_fno_sanitize_memory_use_after_dtor,
+                     false);
     NeedPIE |= !(TC.getTriple().isOSLinux() &&
                  TC.getTriple().getArch() == llvm::Triple::x86_64);
   }
 
   if (AllAddedKinds & Thread) {
     TsanMemoryAccess = Args.hasFlag(options::OPT_fsanitize_thread_memory_access,
                                     options::OPT_fno_sanitize_thread_memory_access,
                                     TsanMemoryAccess);

clang/lib/Frontend/CompilerInvocation.cpp

static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.SanitizeCoverageInline8bitCounters =
       Args.hasArg(OPT_fsanitize_coverage_inline_8bit_counters);
   Opts.SanitizeCoveragePCTable = Args.hasArg(OPT_fsanitize_coverage_pc_table);
   Opts.SanitizeCoverageStackDepth =
       Args.hasArg(OPT_fsanitize_coverage_stack_depth);
   Opts.SanitizeMemoryTrackOrigins =
       getLastArgIntValue(Args, OPT_fsanitize_memory_track_origins_EQ, 0, Diags);
   Opts.SanitizeMemoryUseAfterDtor =
-      Args.hasArg(OPT_fsanitize_memory_use_after_dtor);
+      Args.hasFlag(OPT_fsanitize_memory_use_after_dtor,
+                   OPT_fno_sanitize_memory_use_after_dtor,
+                   false);
   Opts.SanitizeMinimalRuntime = Args.hasArg(OPT_fsanitize_minimal_runtime);
   Opts.SanitizeCfiCrossDso = Args.hasArg(OPT_fsanitize_cfi_cross_dso);
   Opts.SanitizeStats = Args.hasArg(OPT_fsanitize_stats);
   if (Arg *A = Args.getLastArg(OPT_fsanitize_address_use_after_scope,
                                OPT_fno_sanitize_address_use_after_scope)) {
     Opts.SanitizeAddressUseAfterScope =
         A->getOption().getID() == OPT_fsanitize_address_use_after_scope;
   }

clang/test/Driver/fsanitize.c

 // CHECK-NO-TRACK-ORIGINS-NOT: sanitize-memory-track-origins
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=memory -fsanitize-memory-track-origins=2 -pie %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-TRACK-ORIGINS-2
 // CHECK-TRACK-ORIGINS-2: -fsanitize-memory-track-origins=2
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=memory -fsanitize-memory-track-origins=3 -pie %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-TRACK-ORIGINS-3
 // CHECK-TRACK-ORIGINS-3: error: invalid value '3' in '-fsanitize-memory-track-origins=3'
 
-// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory -fsanitize-memory-use-after-dtor -pie %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-MSAN-USE-AFTER-DTOR
-// CHECK-MSAN-USE-AFTER-DTOR: -cc1{{.*}}-fsanitize-memory-use-after-dtor
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory -fsanitize-memory-use-after-dtor %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-USE-AFTER-DTOR
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory -fno-sanitize-memory-use-after-dtor -fsanitize-memory-use-after-dtor %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-USE-AFTER-DTOR
+// CHECK-USE-AFTER-DTOR: -cc1{{.*}}-fsanitize-memory-use-after-dtor
+
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory -fno-sanitize-memory-use-after-dtor %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-USE-AFTER-DTOR-OFF
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory -fsanitize-memory-use-after-dtor -fno-sanitize-memory-use-after-dtor %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-USE-AFTER-DTOR-OFF
+// RUN: %clang -target x86_64-linux-gnu -fsanitize=memory %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-USE-AFTER-DTOR-OFF
+// CHECK-USE-AFTER-DTOR-OFF-NOT: -cc1{{.*}}memory-use-after-dtor
 
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-address-field-padding=0 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-FIELD-PADDING-0
 // CHECK-ASAN-FIELD-PADDING-0-NOT: -fsanitize-address-field-padding
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-address-field-padding=1 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-FIELD-PADDING-1
 // CHECK-ASAN-FIELD-PADDING-1: -fsanitize-address-field-padding=1
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-address-field-padding=2 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-FIELD-PADDING-2
 // CHECK-ASAN-FIELD-PADDING-2: -fsanitize-address-field-padding=2
 // RUN: %clang -target x86_64-linux-gnu -fsanitize=address -fsanitize-address-field-padding=3 %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-ASAN-FIELD-PADDING-3