Emit warning and parse mismatched arguments

Author: Anthony Tran

clang/lib/Driver/SanitizerArgs.cpp

@@ -348,6 +348,29 @@ parseSanitizeSkipHotCutoffArgs(const Driver &D, const llvm::opt::ArgList &Args,
   return Cutoffs;
 }
 
+// Given a set of mismatched bits, TrapOnly (bits the user asked to trap but that aren’t actually enabled),
+// emit a warning based on -fsanitize-trap=NAME
+static void diagnoseTrapOnly(const Driver &D, SanitizerMask &TrapOnly) {
+// Double pass: one for sanitizer groupings, one for leaves (ex: undefined vs. signed-integer-overflow)
+#define SANITIZER(NAME, ID)
+#define SANITIZER_GROUP(NAME, ID, ALIAS) \
+  if (TrapOnly & SanitizerKind::ID##Group) { \
+    D.Diag(diag::warn_drv_sanitize_trap_mismatch) << NAME;                  \
+    TrapOnly &= ~SanitizerKind::ID##Group; \
+    TrapOnly &= ~SanitizerKind::ID; \
+  }
+#include "clang/Basic/Sanitizers.def"
+
+#undef SANITIZER_GROUP
+#define SANITIZER_GROUP(NAME, ID, ALIAS)
+#define SANITIZER(NAME, ID) \
+  if (TrapOnly & SanitizerKind::ID) { \
+    D.Diag(diag::warn_drv_sanitize_trap_mismatch) << NAME; \
+    TrapOnly &= ~SanitizerKind::ID; \
+  }
+#include "clang/Basic/Sanitizers.def"
+}
+
 bool SanitizerArgs::needsFuzzerInterceptors() const {
   return needsFuzzer() && !needsAsanRt() && !needsTsanRt() && !needsMsanRt();
 }
@@ -730,6 +753,25 @@ SanitizerArgs::SanitizerArgs(const ToolChain &TC,
       options::OPT_fno_sanitize_recover_EQ);
   RecoverableKinds &= Kinds;
 
+  // Parse any -fsanitize-trap=<...> flags the user provided, then 
+  // diagnose any which do not have a matching -fsanitize=<...>
+  if (DiagnoseErrors) {
+    SanitizerMask ExplicitTrap = 
+        parseSanitizeArgs(
+        D,
+        Args,
+        false,
+        {},
+        {},
+        {},
+        options::OPT_fsanitize_trap_EQ,
+        options::OPT_fno_sanitize_trap_EQ);
+    SanitizerMask TrapOnly = ExplicitTrap & ~Kinds;
+
+    if (TrapOnly)
+      diagnoseTrapOnly(D, TrapOnly);
+  }
+
   TrappingKinds &= Kinds;
   RecoverableKinds &= ~TrappingKinds;