[Serialization] Explicit function arg lifetimes.

Author: nate-chandler

lib/Serialization/DeserializeSIL.cpp

@@ -946,6 +946,8 @@ SILBasicBlock *SILDeserializer::readSILBasicBlock(SILFunction *Fn,
       auto *fArg = CurrentBB->createFunctionArgument(SILArgTy);
       bool isNoImplicitCopy = (Args[I + 1] >> 16) & 0x1;
       fArg->setNoImplicitCopy(isNoImplicitCopy);
+      auto lifetime = (LifetimeAnnotation::Case)((Args[I + 1] >> 17) & 0x3);
+      fArg->setLifetimeAnnotation(lifetime);
       Arg = fArg;
     } else {
       auto OwnershipKind = ValueOwnershipKind((Args[I + 1] >> 8) & 0xF);

lib/Serialization/ModuleFormat.h

@@ -58,7 +58,7 @@ const uint16_t SWIFTMODULE_VERSION_MAJOR = 0;
 /// describe what change you made. The content of this comment isn't important;
 /// it just ensures a conflict if two people change the module format.
 /// Don't worry about adhering to the 80-column limit for this line.
-const uint16_t SWIFTMODULE_VERSION_MINOR = 703; // remove builtin unsafe guaran
+const uint16_t SWIFTMODULE_VERSION_MINOR = 704; // _eagerMove/_lexical function argument attributes
 
 /// A standard hash seed used for all string hashes in a serialized module.
 ///

lib/Serialization/SerializeSIL.cpp

@@ -626,8 +626,9 @@ void SILSerializer::writeSILBasicBlock(const SILBasicBlock &BB) {
     packedMetadata |= unsigned(SA->getOwnershipKind()) << 8;  // 8 bits
     if (auto *SFA = dyn_cast<SILFunctionArgument>(SA)) {
       packedMetadata |= unsigned(SFA->isNoImplicitCopy()) << 16; // 1 bit
+      packedMetadata |= unsigned(SFA->getLifetimeAnnotation()) << 17; // 2 bits
     }
-    // Used: 17 bits. Free: 15.
+    // Used: 19 bits. Free: 13.
     //
     // TODO: We should be able to shrink the packed metadata of the first two.
     Args.push_back(packedMetadata);

test/SIL/Serialization/function_argument_lifetime_annotation.sil

@@ -0,0 +1,30 @@
+// First parse this and then emit a *.sib. Then read in the *.sib, then recreate
+
+// RUN: %empty-directory(%t)
+// RUN: %target-sil-opt %s -emit-sib -o %t/tmp.sib -module-name eager_move
+// RUN: %target-sil-opt %t/tmp.sib -module-name eager_move | %FileCheck %s
+
+sil_stage canonical
+
+class C {}
+
+// CHECK-LABEL: sil [serialized] [ossa] @one_arg_eager_move : {{.*}} {
+// CHECK: bb0(%0 : @_eagerMove @owned $C):
+// CHECK: } // end sil function 'one_arg_eager_move'
+sil [serialized] [ossa] @one_arg_eager_move : $@convention(thin) (@owned C) -> () {
+bb0(%instance : @_eagerMove @owned $C):
+  destroy_value %instance : $C
+  %retval = tuple()
+  return %retval : $()
+}
+
+// CHECK-LABEL: sil [serialized] [ossa] @one_arg_lexical : {{.*}} {
+// CHECK: bb0(%0 : @_lexical @owned $C):
+// CHECK: } // end sil function 'one_arg_lexical'
+sil [serialized] [ossa] @one_arg_lexical : $@convention(thin) (@owned C) -> () {
+bb0(%instance : @_lexical @owned $C):
+  destroy_value %instance : $C
+  %retval = tuple()
+  return %retval : $()
+}
+