[clang] [sanitizer] Apply AlwaysIn/Out in parseSanitizeArgs (PR #129405)

[Thurston Dang via cfe-commits]

https://github.com/thurstond created https://github.com/llvm/llvm-project/pull/129405

For backwards compatibility, `parseSanitizeArgs`/`parseSanitizeTrapArgs` had an incomplete refactoring in https://github.com/llvm/llvm-project/pull/119819, in order to accommodate the special case of vptr in -fsanitize=undefined and its interaction with -fsanitize-trap=undefined. Now that vptr is no longer part of -fsanitize=undefined (https://github.com/llvm/llvm-project/pull/121115), this patch changes parseSanitizeArgs to apply the AlwaysIn/Out invariants in parseSanitizeArgs, which allows simplifying calls to parseSanitizeArgs.

This is not quite NFC: it changes the error message of -fsanitize-trap=vptr.

>From 69476cfd0ba3444566b4116a01bb06b73da26e3c Mon Sep 17 00:00:00 2001
From: Thurston Dang <thurston at google.com>
Date: Sat, 1 Mar 2025 21:59:06 +0000
Subject: [PATCH] [sanitizer] Apply AlwaysIn/Out in parseSanitizeArgs

For backwards compatibility, parseSanitizeArgs had an incomplete refactoring in https://github.com/llvm/llvm-project/pull/119819, in order to accommodate the special case of vptr in -fsanitize=undefined and its interaction with -fsanitize-trap=undefined. Now that vptr is no longer part of UBSan (https://github.com/llvm/llvm-project/pull/121115), this patch changes parseSanitizeArgs to apply the AlwaysIn/Out invariants in parseSanitizeArgs, which allows simplifying calls to parseSanitizeArgs.

Note that this does change the error message of -fsanitize-trap=vptr.
---
 clang/lib/Driver/SanitizerArgs.cpp | 14 ++++----------
 clang/test/Driver/fsanitize.c      |  2 +-
 2 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/clang/lib/Driver/SanitizerArgs.cpp b/clang/lib/Driver/SanitizerArgs.cpp
index 6e75001585c61..f5b0bc5ce720f 100644
--- a/clang/lib/Driver/SanitizerArgs.cpp
+++ b/clang/lib/Driver/SanitizerArgs.cpp
@@ -261,11 +261,8 @@ static SanitizerMask setGroupBits(SanitizerMask Kinds) {
 }
 
 // Computes the sanitizer mask as:
-//     Default + Arguments (in or out)
+//     Default + Arguments (in or out) + AlwaysIn - AlwaysOut
 // with arguments parsed from left to right.
-//
-// Error messages are printed if the AlwaysIn or AlwaysOut invariants are
-// violated, but the caller must enforce these invariants themselves.
 static SanitizerMask
 parseSanitizeArgs(const Driver &D, const llvm::opt::ArgList &Args,
                   bool DiagnoseErrors, SanitizerMask Default,
@@ -315,6 +312,9 @@ parseSanitizeArgs(const Driver &D, const llvm::opt::ArgList &Args,
     }
   }
 
+  Output |= AlwaysIn;
+  Output &= ~AlwaysOut;
+
   return Output;
 }
 
@@ -324,10 +324,6 @@ static SanitizerMask parseSanitizeTrapArgs(const Driver &D,
   SanitizerMask AlwaysTrap; // Empty
   SanitizerMask NeverTrap = ~(setGroupBits(TrappingSupported));
 
-  // N.B. We do *not* enforce NeverTrap. This maintains the behavior of
-  // '-fsanitize=undefined -fsanitize-trap=undefined'
-  // (clang/test/Driver/fsanitize.c ), which is that vptr is not enabled at all
-  // (not even in recover mode) in order to avoid the need for a ubsan runtime.
   return parseSanitizeArgs(D, Args, DiagnoseErrors, TrappingDefault, AlwaysTrap,
                            NeverTrap, options::OPT_fsanitize_trap_EQ,
                            options::OPT_fno_sanitize_trap_EQ);
@@ -725,8 +721,6 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
       D, Args, DiagnoseErrors, RecoverableByDefault, AlwaysRecoverable,
       Unrecoverable, options::OPT_fsanitize_recover_EQ,
       options::OPT_fno_sanitize_recover_EQ);
-  RecoverableKinds |= AlwaysRecoverable;
-  RecoverableKinds &= ~Unrecoverable;
   RecoverableKinds &= Kinds;
 
   TrappingKinds &= Kinds;
diff --git a/clang/test/Driver/fsanitize.c b/clang/test/Driver/fsanitize.c
index 79c936a79ffd2..9eb6579ce30ab 100644
--- a/clang/test/Driver/fsanitize.c
+++ b/clang/test/Driver/fsanitize.c
@@ -149,7 +149,7 @@
 // CHECK-FSANITIZE-SHIFT-PARTIAL: "-fsanitize=shift-exponent"
 
 // RUN: not %clang --target=x86_64-linux-gnu -fsanitize=vptr -fsanitize-trap=vptr %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-VPTR-TRAP-UNDEF
-// CHECK-VPTR-TRAP-UNDEF: error: invalid argument '-fsanitize=vptr' not allowed with '-fsanitize-trap=undefined'
+// CHECK-VPTR-TRAP-UNDEF: error: unsupported argument 'vptr' to option '-fsanitize-trap='
 
 // RUN: %clang --target=x86_64-linux-gnu -fsanitize=vptr -fsanitize-undefined-trap-on-error %s -###