SIL: Make the verifier's ImmutableAddressUseVerifier generally available

Also, make it more tolerant to instructions and builtins, which are not explicitly handled.
This avoids crashes when new instructions are added. We got lucky that this didn't happen so far.

Author: eeckstein

include/swift/SIL/InstructionUtils.h

@@ -247,6 +247,13 @@ lookUpFunctionInWitnessTable(WitnessMethodInst *wmi, SILModule::LinkingMode link
 /// struct-with-deinit drops the deinit.
 bool shouldExpand(SILModule &module, SILType ty);
 
+/// Returns true if `arg` is mutated.
+/// if `ignoreDestroys` is true, `destroy_addr` instructions are ignored.
+/// `defaultIsMutating` specifies the state of instructions which are not explicitly handled.
+/// For historical reasons this utility is implemented in SILVerifier.cpp.
+bool isIndirectArgumentMutated(SILFunctionArgument *arg, bool ignoreDestroys = false,
+                               bool defaultIsMutating = false);
+
 } // end namespace swift
 
 #endif

lib/SIL/Verifier/SILVerifier.cpp

@@ -35,6 +35,7 @@
 #include "swift/SIL/DebugUtils.h"
 #include "swift/SIL/Dominance.h"
 #include "swift/SIL/DynamicCasts.h"
+#include "swift/SIL/InstructionUtils.h"
 #include "swift/SIL/MemAccessUtils.h"
 #include "swift/SIL/OwnershipLiveness.h"
 #include "swift/SIL/OwnershipUtils.h"
@@ -572,6 +573,11 @@ void verifyKeyPathComponent(SILModule &M,
 /// open_existential_addr. We should expand it as needed.
 struct ImmutableAddressUseVerifier {
   SmallVector<Operand *, 32> worklist;
+  bool ignoreDestroys;
+  bool defaultIsMutating;
+
+  ImmutableAddressUseVerifier(bool ignoreDestroys = false, bool defaultIsMutating = false)
+    : ignoreDestroys(ignoreDestroys), defaultIsMutating(defaultIsMutating) {}
 
   bool isConsumingOrMutatingArgumentConvention(SILArgumentConvention conv) {
     switch (conv) {
@@ -704,10 +710,9 @@ struct ImmutableAddressUseVerifier {
           }
         }
 
-        // Otherwise this is a builtin that we are not expecting to see, so bail
-        // and assert.
-        llvm::errs() << "Unhandled, unexpected builtin instruction: " << *inst;
-        llvm_unreachable("invoking standard assertion failure");
+        // Otherwise this is a builtin that we are not expecting to see.
+        if (defaultIsMutating)
+          return true;
         break;
       }
       case SILInstructionKind::MarkDependenceInst:
@@ -775,7 +780,9 @@ struct ImmutableAddressUseVerifier {
         else
           break;
       case SILInstructionKind::DestroyAddrInst:
-        return true;
+        if (!ignoreDestroys)
+          return true;
+        break;
       case SILInstructionKind::UpcastInst:
       case SILInstructionKind::UncheckedAddrCastInst: {
         if (isAddrCastToNonConsuming(cast<SingleValueInstruction>(inst))) {
@@ -841,9 +848,7 @@ struct ImmutableAddressUseVerifier {
           }
           break;
         }
-        llvm::errs() << "Unhandled, unexpected instruction: " << *inst;
-        llvm_unreachable("invoking standard assertion failure");
-        break;
+        return true;
       }
       case SILInstructionKind::TuplePackElementAddrInst: {
         if (&cast<TuplePackElementAddrInst>(inst)->getOperandRef(
@@ -865,8 +870,8 @@ struct ImmutableAddressUseVerifier {
         return false;
       }
       default:
-        llvm::errs() << "Unhandled, unexpected instruction: " << *inst;
-        llvm_unreachable("invoking standard assertion failure");
+        if (defaultIsMutating)
+          return true;
         break;
       }
     }
@@ -7385,6 +7390,11 @@ class SILVerifier : public SILVerifierBase<SILVerifier> {
 #undef require
 #undef requireObjectType
 
+bool swift::isIndirectArgumentMutated(SILFunctionArgument *arg, bool ignoreDestroys,
+                                      bool defaultIsMutating) {
+  return ImmutableAddressUseVerifier(ignoreDestroys, defaultIsMutating).isMutatingOrConsuming(arg);
+}
+
 //===----------------------------------------------------------------------===//
 //                     Out of Line Verifier Run Functions
 //===----------------------------------------------------------------------===//