Diagnose use of incompatible sanitizers

Emit an error when incompatible sanitizer are configured through command
line options. Previously the last one configured prevailed and others
were silently ignored.

Additionally use a set to represent configured sanitizers, making it
possible to enable multiple sanitizers at once. At least in principle,
since currently all of them are considered to be incompatible with
others.

src/rustllvm/PassWrapper.cpp

@@ -711,11 +711,12 @@ enum class LLVMRustOptStage {
 };
 
 struct LLVMRustSanitizerOptions {
-  bool SanitizeMemory;
-  bool SanitizeThread;
   bool SanitizeAddress;
-  bool SanitizeRecover;
-  int SanitizeMemoryTrackOrigins;
+  bool SanitizeAddressRecover;
+  bool SanitizeMemory;
+  bool SanitizeMemoryRecover;
+  int  SanitizeMemoryTrackOrigins;
+  bool SanitizeThread;
 };
 
 extern "C" void
@@ -802,7 +803,7 @@ LLVMRustOptimizeWithNewPassManager(
     if (SanitizerOptions->SanitizeMemory) {
       MemorySanitizerOptions Options(
           SanitizerOptions->SanitizeMemoryTrackOrigins,
-          SanitizerOptions->SanitizeRecover,
+          SanitizerOptions->SanitizeMemoryRecover,
           /*CompileKernel=*/false);
 #if LLVM_VERSION_GE(10, 0)
       PipelineStartEPCallbacks.push_back([Options](ModulePassManager &MPM) {
@@ -836,14 +837,14 @@ LLVMRustOptimizeWithNewPassManager(
       OptimizerLastEPCallbacks.push_back(
         [SanitizerOptions](FunctionPassManager &FPM, PassBuilder::OptimizationLevel Level) {
           FPM.addPass(AddressSanitizerPass(
-              /*CompileKernel=*/false, SanitizerOptions->SanitizeRecover,
+              /*CompileKernel=*/false, SanitizerOptions->SanitizeAddressRecover,
               /*UseAfterScope=*/true));
         }
       );
       PipelineStartEPCallbacks.push_back(
         [SanitizerOptions](ModulePassManager &MPM) {
           MPM.addPass(ModuleAddressSanitizerPass(
-              /*CompileKernel=*/false, SanitizerOptions->SanitizeRecover));
+              /*CompileKernel=*/false, SanitizerOptions->SanitizeAddressRecover));
         }
       );
     }