GlobalISel: Abort in ResetMachineFunctionPass if fallback isn't enabled

When GlobalISel is configured to abort rather than fallback the only
thing that resetting the machine function does is make things harder
to debug. If we ever get to this point in the abort configuration it
indicates that we've already hit a bug, so this changes the behaviour
to abort instead.

llvm-svn: 291977

llvm/include/llvm/CodeGen/Passes.h

@@ -60,7 +60,9 @@ namespace llvm {
   /// as if it was just created.
   /// If EmitFallbackDiag is true, the pass will emit a
   /// DiagnosticInfoISelFallback for every MachineFunction it resets.
-  MachineFunctionPass *createResetMachineFunctionPass(bool EmitFallbackDiag);
+  /// If AbortOnFailedISel is true, abort compilation instead of resetting.
+  MachineFunctionPass *createResetMachineFunctionPass(bool EmitFallbackDiag,
+                                                      bool AbortOnFailedISel);
 
   /// createCodeGenPreparePass - Transform the code to expose more pattern
   /// matching during instruction selection.

llvm/lib/CodeGen/LLVMTargetMachine.cpp

@@ -172,7 +172,8 @@ addPassesToGenerateCode(LLVMTargetMachine *TM, PassManagerBase &PM,
 
     // Pass to reset the MachineFunction if the ISel failed.
     PM.add(createResetMachineFunctionPass(
-        PassConfig->reportDiagnosticWhenGlobalISelFallback()));
+        PassConfig->reportDiagnosticWhenGlobalISelFallback(),
+        PassConfig->isGlobalISelAbortEnabled()));
 
     // Provide a fallback path when we do not want to abort on
     // not-yet-supported input.

llvm/lib/CodeGen/ResetMachineFunctionPass.cpp

@@ -30,17 +30,23 @@ namespace {
     /// Tells whether or not this pass should emit a fallback
     /// diagnostic when it resets a function.
     bool EmitFallbackDiag;
+    /// Whether we should abort immediately instead of resetting the function.
+    bool AbortOnFailedISel;
 
   public:
     static char ID; // Pass identification, replacement for typeid
-    ResetMachineFunction(bool EmitFallbackDiag = false)
-        : MachineFunctionPass(ID), EmitFallbackDiag(EmitFallbackDiag) {}
+    ResetMachineFunction(bool EmitFallbackDiag = false,
+                         bool AbortOnFailedISel = false)
+        : MachineFunctionPass(ID), EmitFallbackDiag(EmitFallbackDiag),
+          AbortOnFailedISel(AbortOnFailedISel) {}
 
     StringRef getPassName() const override { return "ResetMachineFunction"; }
 
     bool runOnMachineFunction(MachineFunction &MF) override {
       if (MF.getProperties().hasProperty(
               MachineFunctionProperties::Property::FailedISel)) {
+        if (AbortOnFailedISel)
+          report_fatal_error("Instruction selection failed");
         DEBUG(dbgs() << "Reseting: " << MF.getName() << '\n');
         ++NumFunctionsReset;
         MF.reset();
@@ -62,6 +68,7 @@ INITIALIZE_PASS(ResetMachineFunction, DEBUG_TYPE,
                 "reset machine function if ISel failed", false, false)
 
 MachineFunctionPass *
-llvm::createResetMachineFunctionPass(bool EmitFallbackDiag = false) {
-  return new ResetMachineFunction(EmitFallbackDiag);
+llvm::createResetMachineFunctionPass(bool EmitFallbackDiag = false,
+                                     bool AbortOnFailedISel = false) {
+  return new ResetMachineFunction(EmitFallbackDiag, AbortOnFailedISel);
 }