[SILGen] Output a different message for failed IUO force-unwraps

lib/SILGen/Conversion.h

@@ -33,6 +33,8 @@ class Conversion {
     BridgeToObjC,
 
     /// A bridging conversion to a foreign type following a force.
+    /// Although it's not reflected in the name, this is always an
+    /// implicit force cast.
     ForceAndBridgeToObjC,
 
     /// A bridging conversion from a foreign type.

lib/SILGen/SILGenConvert.cpp

@@ -182,7 +182,8 @@ auto SILGenFunction::emitSourceLocationArgs(SourceLoc sourceLoc,
 
 ManagedValue
 SILGenFunction::emitPreconditionOptionalHasValue(SILLocation loc,
-                                                 ManagedValue optional) {
+                                                 ManagedValue optional,
+                                                 bool isImplicitUnwrap) {
   // Generate code to the optional is present, and if not, abort with a message
   // (provided by the stdlib).
   SILBasicBlock *contBB = createBasicBlock();
@@ -217,12 +218,19 @@ SILGenFunction::emitPreconditionOptionalHasValue(SILLocation loc,
         getASTContext().getDiagnoseUnexpectedNilOptional(nullptr)) {
     auto args = emitSourceLocationArgs(loc.getSourceLoc(), loc);
 
+    auto i1Ty = SILType::getBuiltinIntegerType(1, getASTContext());
+    auto isImplicitUnwrapLiteral =
+      B.createIntegerLiteral(loc, i1Ty, isImplicitUnwrap);
+    auto isImplicitUnwrapValue =
+      ManagedValue::forUnmanaged(isImplicitUnwrapLiteral);
+
     emitApplyOfLibraryIntrinsic(loc, diagnoseFailure, SubstitutionMap(),
                                 {
                                   args.filenameStartPointer,
                                   args.filenameLength,
                                   args.filenameIsAscii,
-                                  args.line
+                                  args.line,
+                                  isImplicitUnwrapValue
                                 },
                                 SGFContext());
   }
@@ -268,10 +276,11 @@ SILValue SILGenFunction::emitDoesOptionalHaveValue(SILLocation loc,
 
 ManagedValue SILGenFunction::emitCheckedGetOptionalValueFrom(SILLocation loc,
                                                       ManagedValue src,
+                                                      bool isImplicitUnwrap,
                                                       const TypeLowering &optTL,
                                                       SGFContext C) {
   // TODO: Make this take optTL.
-  return emitPreconditionOptionalHasValue(loc, src);
+  return emitPreconditionOptionalHasValue(loc, src, isImplicitUnwrap);
 }
 
 ManagedValue SILGenFunction::emitUncheckedGetOptionalValueFrom(
@@ -1103,7 +1112,9 @@ ManagedValue Conversion::emit(SILGenFunction &SGF, SILLocation loc,
   case ForceAndBridgeToObjC: {
     auto &tl = SGF.getTypeLowering(value.getType());
     auto sourceValueType = getBridgingSourceType().getOptionalObjectType();
-    value = SGF.emitCheckedGetOptionalValueFrom(loc, value, tl, SGFContext());
+    value = SGF.emitCheckedGetOptionalValueFrom(loc, value,
+                                                /*isImplicitUnwrap*/ true,
+                                                tl, SGFContext());
     return SGF.emitNativeToBridgedValue(loc, value, sourceValueType,
                                         getBridgingResultType(),
                                         getBridgingLoweredResultType(), C);
@@ -1438,7 +1449,11 @@ Lowering::emitPeepholedConversions(SILGenFunction &SGF, SILLocation loc,
 
     auto value = produceOrigValue(SGF, loc, SGFContext());
     auto &optTL = SGF.getTypeLowering(value.getType());
-    return SGF.emitCheckedGetOptionalValueFrom(loc, value, optTL, C);
+    // isForceUnwrap is hardcoded true because hint.isForced() is only
+    // set by implicit force unwraps.
+    return SGF.emitCheckedGetOptionalValueFrom(loc, value,
+                                               /*isForceUnwrap*/ true,
+                                               optTL, C);
   };
 
   auto getBridgingSourceType = [&] {

lib/SILGen/SILGenExpr.cpp

@@ -5165,7 +5165,9 @@ RValue RValueEmitter::emitForceValue(ForceValueExpr *loc, Expr *E,
   // If this is an implicit force of an ImplicitlyUnwrappedOptional,
   // and we're emitting into an unbridging conversion, try adjusting the
   // context.
-  if (loc->isImplicit() && loc->isForceOfImplicitlyUnwrappedOptional()) {
+  bool isImplicitUnwrap = loc->isImplicit() &&
+    loc->isForceOfImplicitlyUnwrappedOptional();
+  if (isImplicitUnwrap) {
     if (auto conv = C.getAsConversion()) {
       if (auto adjusted = conv->getConversion().adjustForInitialForceValue()) {
         auto value =
@@ -5182,7 +5184,7 @@ RValue RValueEmitter::emitForceValue(ForceValueExpr *loc, Expr *E,
   const TypeLowering &optTL = SGF.getTypeLowering(E->getType());
   ManagedValue opt = SGF.emitRValueAsSingleValue(E);
   ManagedValue V =
-    SGF.emitCheckedGetOptionalValueFrom(loc, opt, optTL, C);
+    SGF.emitCheckedGetOptionalValueFrom(loc, opt, isImplicitUnwrap, optTL, C);
   return RValue(SGF, loc, valueType->getCanonicalType(), V);
 }
 
@@ -5695,8 +5697,10 @@ void SILGenFunction::emitIgnoredExpr(Expr *E) {
 
     for (auto &FVE : reversed(forceValueExprs)) {
       const TypeLowering &optTL = getTypeLowering(FVE->getSubExpr()->getType());
+      bool isImplicitUnwrap = FVE->isImplicit() &&
+          FVE->isForceOfImplicitlyUnwrappedOptional();
       value = emitCheckedGetOptionalValueFrom(
-          FVE, value, optTL, SGFContext::AllowImmediatePlusZero);
+          FVE, value, isImplicitUnwrap, optTL, SGFContext::AllowImmediatePlusZero);
     }
     return;
   }

lib/SILGen/SILGenFunction.h

@@ -810,13 +810,15 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
   /// _diagnoseUnexpectedNilOptional if the optional has no value. Return the
   /// MangedValue resulting from the success case.
   ManagedValue emitPreconditionOptionalHasValue(SILLocation loc,
-                                                ManagedValue optional);
+                                                ManagedValue optional,
+                                                bool isImplicitUnwrap);
 
   /// \brief Emit a call to the library intrinsic _getOptionalValue
   /// given the address of the optional, which checks that an optional contains
   /// some value and either returns the value or traps if there is none.
   ManagedValue emitCheckedGetOptionalValueFrom(SILLocation loc,
                                                ManagedValue addr,
+                                               bool isImplicitUnwrap,
                                                const TypeLowering &optTL,
                                                SGFContext C);
 

lib/SILGen/SILGenLValue.cpp

@@ -688,19 +688,22 @@ namespace {
   /// A physical path component which force-projects the address of
   /// the value of an optional l-value.
   class ForceOptionalObjectComponent : public PhysicalPathComponent {
+    bool isImplicitUnwrap;
   public:
-    ForceOptionalObjectComponent(LValueTypeData typeData)
-      : PhysicalPathComponent(typeData, OptionalObjectKind) {}
+    ForceOptionalObjectComponent(LValueTypeData typeData,
+                                 bool isImplicitUnwrap)
+      : PhysicalPathComponent(typeData, OptionalObjectKind),
+        isImplicitUnwrap(isImplicitUnwrap) {}
 
     ManagedValue offset(SILGenFunction &SGF, SILLocation loc, ManagedValue base,
                         AccessKind accessKind) && override {
       // Assert that the optional value is present and return the projected out
       // payload.
-      return SGF.emitPreconditionOptionalHasValue(loc, base);
+      return SGF.emitPreconditionOptionalHasValue(loc, base, isImplicitUnwrap);
     }
 
     void dump(raw_ostream &OS, unsigned indent) const override {
-      OS.indent(indent) << "ForceOptionalObjectComponent()\n";
+      OS.indent(indent) << "ForceOptionalObjectComponent(" << isImplicitUnwrap << ")\n";
     }
   };
 
@@ -3004,7 +3007,9 @@ LValue SILGenLValue::visitForceValueExpr(ForceValueExpr *e,
   LValue lv = visitRec(e->getSubExpr(), accessKind,
                        options.forComputedBaseLValue());
   LValueTypeData typeData = getOptionalObjectTypeData(SGF, lv.getTypeData());
-  lv.add<ForceOptionalObjectComponent>(typeData);
+  bool isImplicitUnwrap = e->isImplicit() &&
+    e->isForceOfImplicitlyUnwrappedOptional(); 
+  lv.add<ForceOptionalObjectComponent>(typeData, isImplicitUnwrap);
   return lv;
 }
 

lib/SILGen/SILGenPoly.cpp

@@ -398,7 +398,11 @@ ManagedValue Transform::transform(ManagedValue v,
   // optional or Any, force it.
   if (inputIsOptional && !outputIsOptional &&
       !outputSubstType->isExistentialType()) {
+    // isImplicitUnwrap is hardcoded true because the looseness in types of
+    // @objc witnesses/overrides that we're handling here only allows IUOs,
+    // not explicit Optionals.
     v = SGF.emitCheckedGetOptionalValueFrom(Loc, v,
+                                            /*isImplicitUnwrap*/ true, 
                                             SGF.getTypeLowering(v.getType()),
                                             SGFContext());
 

stdlib/private/StdlibUnittest/StdlibUnittest.swift

@@ -819,17 +819,17 @@ public func expectNotNil<T>(_ value: T?,
   return value
 }
 
-public func expectCrashLater() {
+public func expectCrashLater(withMessage message: String = "") {
   print("\(_stdlibUnittestStreamPrefix);expectCrash;\(_anyExpectFailed)")
 
   var stderr = _Stderr()
-  print("\(_stdlibUnittestStreamPrefix);expectCrash", to: &stderr)
+  print("\(_stdlibUnittestStreamPrefix);expectCrash;\(message)", to: &stderr)
 
   _seenExpectCrash = true
 }
 
-public func expectCrash(executing: () -> Void) -> Never {
-  expectCrashLater()
+public func expectCrash(withMessage message: String = "", executing: () -> Void) -> Never {
+  expectCrashLater(withMessage: message)
   executing()
   expectUnreachable()
   fatalError()
@@ -1080,6 +1080,7 @@ struct _ParentProcess {
 
     var stdoutSeenCrashDelimiter = false
     var stderrSeenCrashDelimiter = false
+    var expectingPreCrashMessage = ""
     var stdoutEnd = false
     var stderrEnd = false
     var capturedCrashStdout: [Substring] = []
@@ -1090,14 +1091,16 @@ struct _ParentProcess {
       var line = line[...]
       if let index = findSubstring(line, _stdlibUnittestStreamPrefix) {
         let controlMessage =
-            line[index..<line.endIndex].split(separator: ";")
+            line[index..<line.endIndex].split(separator: ";",
+                              omittingEmptySubsequences: false)
         switch controlMessage[1] {
         case "expectCrash":
           if isStdout {
             stdoutSeenCrashDelimiter = true
             anyExpectFailedInChild = controlMessage[2] == "true"
           } else {
             stderrSeenCrashDelimiter = true
+            expectingPreCrashMessage = String(controlMessage[2])
           }
         case "end":
           if isStdout {
@@ -1114,6 +1117,11 @@ struct _ParentProcess {
           return (done: stdoutEnd && stderrEnd, ())
         }
       }
+      if !expectingPreCrashMessage.isEmpty
+          && findSubstring(line, expectingPreCrashMessage) != nil {
+        line = "OK: saw expected pre-crash message in \"\(line)\""[...]
+        expectingPreCrashMessage = ""
+      }
       if isStdout {
         if stdoutSeenCrashDelimiter {
           capturedCrashStdout.append(line)
@@ -1122,7 +1130,16 @@ struct _ParentProcess {
         if stderrSeenCrashDelimiter {
           capturedCrashStderr.append(line)
           if findSubstring(line, _crashedPrefix) != nil {
-            line = "OK: saw expected \"\(line.lowercased())\""[...]
+            if !expectingPreCrashMessage.isEmpty {
+              line = """
+                      FAIL: saw expected "\(line.lowercased())", but without \
+                      message "\(expectingPreCrashMessage)" before it
+                      """[...]
+              anyExpectFailedInChild = true
+            }
+            else {
+              line = "OK: saw expected \"\(line.lowercased())\""[...]
+            }
           }
         }
       }
@@ -1152,8 +1169,8 @@ struct _ParentProcess {
       }
       return (
         anyExpectFailedInChild,
-        stdoutSeenCrashDelimiter || stderrSeenCrashDelimiter, status,
-        capturedCrashStdout, capturedCrashStderr)
+        stdoutSeenCrashDelimiter || stderrSeenCrashDelimiter,
+        status, capturedCrashStdout, capturedCrashStderr)
     }
 
     // We reached EOF on stdout and stderr and we did not see "end" markers, so
@@ -1163,8 +1180,8 @@ struct _ParentProcess {
     let status = _waitForChild()
     return (
       anyExpectFailedInChild,
-      stdoutSeenCrashDelimiter || stderrSeenCrashDelimiter, status,
-      capturedCrashStdout, capturedCrashStderr)
+      stdoutSeenCrashDelimiter || stderrSeenCrashDelimiter,
+      status, capturedCrashStdout, capturedCrashStderr)
   }
 
   internal mutating func _shutdownChild() -> (failed: Bool, Void) {

stdlib/public/core/Optional.swift

@@ -299,9 +299,12 @@ public // COMPILER_INTRINSIC
 func _diagnoseUnexpectedNilOptional(_filenameStart: Builtin.RawPointer,
                                     _filenameLength: Builtin.Word,
                                     _filenameIsASCII: Builtin.Int1,
-                                    _line: Builtin.Word) {
+                                    _line: Builtin.Word,
+                                    _isImplicitUnwrap: Builtin.Int1) {
   _preconditionFailure(
-    "Unexpectedly found nil while unwrapping an Optional value",
+    Bool(_isImplicitUnwrap)
+      ? "Unexpectedly found nil while implicitly unwrapping an Optional value"
+      : "Unexpectedly found nil while unwrapping an Optional value",
     file: StaticString(_start: _filenameStart,
                        utf8CodeUnitCount: _filenameLength,
                        isASCII: _filenameIsASCII),

test/SILGen/objc_bridging_peephole.swift

@@ -75,7 +75,7 @@ func testNonNullMethodResult(dummy: DummyClass) {
   // CHECK-NEXT: switch_enum [[RESULT]]
   //
   // CHECK:    bb1:
-  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_lineyBp_BwBi1_BwtF
+  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_line17_isImplicitUnwrapyBp_BwBi1_BwBi1_tF
   // CHECK:    bb2([[RESULT:%.*]] : @owned $NSString):
   // CHECK:      [[BORROWED_RESULT:%.*]] = begin_borrow [[RESULT]]
   // CHECK:      [[USE:%.*]] = function_ref @$S22objc_bridging_peephole5useNSyySo8NSStringCF
@@ -86,7 +86,7 @@ func testNonNullMethodResult(dummy: DummyClass) {
   // CHECK-NEXT: [[RESULT:%.*]] = apply [[METHOD]]([[SELF]])
   // CHECK-NEXT: switch_enum [[RESULT]]
   // CHECK:    bb3:
-  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_lineyBp_BwBi1_BwtF
+  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_line17_isImplicitUnwrapyBp_BwBi1_BwBi1_tF
   // CHECK:    bb4([[RESULT:%.*]] : @owned $NSString):
   // CHECK-NEXT: [[ANYOBJECT:%.*]] = init_existential_ref [[RESULT]] : $NSString : $NSString, $AnyObject
   // CHECK-NEXT: [[BORROWED_ANYOBJECT:%.*]] = begin_borrow [[ANYOBJECT]]
@@ -104,7 +104,7 @@ func testForcedMethodResult(dummy: DummyClass) {
   // CHECK-NEXT: [[RESULT:%.*]] = apply [[METHOD]]([[SELF]])
   // CHECK-NEXT: switch_enum [[RESULT]]
   // CHECK:    bb1:
-  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_lineyBp_BwBi1_BwtF
+  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_line17_isImplicitUnwrapyBp_BwBi1_BwBi1_tF
   // CHECK:    bb2([[RESULT:%.*]] : @owned $NSString):
   // CHECK:      [[BORROWED_RESULT:%.*]] = begin_borrow [[RESULT]]
   // CHECK:      [[USE:%.*]] = function_ref @$S22objc_bridging_peephole5useNSyySo8NSStringCF
@@ -197,7 +197,7 @@ func testNonNullPropertyValue(dummy: DummyClass) {
   // CHECK:       [[RESULT:%.*]] = apply [[METHOD]]([[SELF]])
   // CHECK:       switch_enum [[RESULT]]
   // CHECK:    bb1:
-  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_lineyBp_BwBi1_BwtF
+  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_line17_isImplicitUnwrapyBp_BwBi1_BwBi1_tF
   // CHECK:    bb2([[RESULT:%.*]] : @owned $NSString):
   // CHECK:      [[BORROWED_RESULT:%.*]] = begin_borrow [[RESULT]]
   // CHECK:      [[USE:%.*]] = function_ref @$S22objc_bridging_peephole5useNSyySo8NSStringCF
@@ -208,7 +208,7 @@ func testNonNullPropertyValue(dummy: DummyClass) {
   // CHECK:      [[RESULT:%.*]] = apply [[METHOD]]([[SELF]])
   // CHECK:      switch_enum [[RESULT]]
   // CHECK:    bb3:
-  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_lineyBp_BwBi1_BwtF
+  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_line17_isImplicitUnwrapyBp_BwBi1_BwBi1_tF
   // CHECK:    bb4([[RESULT:%.*]] : @owned $NSString):
   // CHECK:      [[ANYOBJECT:%.*]] = init_existential_ref [[RESULT]] : $NSString : $NSString, $AnyObject
   // CHECK:      [[BORROWED_ANYOBJECT:%.*]] = begin_borrow [[ANYOBJECT]]
@@ -226,7 +226,7 @@ func testForcedPropertyValue(dummy: DummyClass) {
   // CHECK:      [[RESULT:%.*]] = apply [[METHOD]]([[SELF]])
   // CHECK:      switch_enum [[RESULT]]
   // CHECK:    bb1:
-  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_lineyBp_BwBi1_BwtF
+  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_line17_isImplicitUnwrapyBp_BwBi1_BwBi1_tF
   // CHECK:    bb2([[RESULT:%.*]] : @owned $NSString):
   // CHECK:      [[BORROWED_RESULT:%.*]] = begin_borrow [[RESULT]]
   // CHECK:      [[USE:%.*]] = function_ref @$S22objc_bridging_peephole5useNSyySo8NSStringCF
@@ -281,7 +281,7 @@ func testNonnullSubscriptGet(object: NonnullSubscript, index: AnyObject) {
   // CHECK:      [[RESULT:%.*]] = apply [[METHOD]]([[INDEX]], [[SELF]])
   // CHECK-NEXT: destroy_value [[INDEX]] : $AnyObject
   // CHECK-NEXT: switch_enum [[RESULT]]
-  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_lineyBp_BwBi1_BwtF
+  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_line17_isImplicitUnwrapyBp_BwBi1_BwBi1_tF
   // CHECK:    bb{{[0-9]+}}([[RESULT:%.*]] : @owned $NSString):
   // CHECK:      [[BORROWED_RESULT:%.*]] = begin_borrow [[RESULT]]
   // CHECK:      [[USE:%.*]] = function_ref @$S22objc_bridging_peephole5useNSyySo8NSStringCF
@@ -326,7 +326,7 @@ func testNullproneSubscriptGet(object: NullproneSubscript, index: AnyObject) {
   // CHECK:      [[RESULT:%.*]] = apply [[METHOD]]([[INDEX]], [[SELF]])
   // CHECK-NEXT: destroy_value [[INDEX]] : $AnyObject
   // CHECK-NEXT: switch_enum [[RESULT]]
-  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_lineyBp_BwBi1_BwtF
+  // CHECK:      function_ref @$Ss30_diagnoseUnexpectedNilOptional14_filenameStart01_E6Length01_E7IsASCII5_line17_isImplicitUnwrapyBp_BwBi1_BwBi1_tF
   // CHECK:    bb{{[0-9]+}}([[RESULT:%.*]] : @owned $NSString):
   // CHECK:      [[BORROWED_RESULT:%.*]] = begin_borrow [[RESULT]]
   // CHECK:      [[USE:%.*]] = function_ref @$S22objc_bridging_peephole5useNSyySo8NSStringCF

test/SILGen/objc_witnesses.swift

@@ -43,6 +43,15 @@ extension Gizmo : Bells {
 // CHECK:   [[INIT:%[0-9]+]] = function_ref @$SSo5GizmoC{{[_0-9a-zA-Z]*}}fC : $@convention(method) (Int, @thick Gizmo.Type) -> @owned Optional<Gizmo>
 // CHECK:   [[IUO_RESULT:%[0-9]+]] = apply [[INIT]]([[I]], [[META]]) : $@convention(method) (Int, @thick Gizmo.Type) -> @owned Optional<Gizmo>
 // CHECK:   switch_enum [[IUO_RESULT]]
+// CHECK: bb1:
+// CHECK-NEXT:   [[FILESTR:%.*]] = string_literal utf8 "
+// CHECK-NEXT:   [[FILESIZ:%.*]] = integer_literal $Builtin.Word, 
+// CHECK-NEXT:   [[FILEASC:%.*]] = integer_literal $Builtin.Int1, 
+// CHECK-NEXT:   [[LINE:%.*]] = integer_literal $Builtin.Word, 
+// CHECK-NEXT:   [[COLUMN:%.*]] = integer_literal $Builtin.Word, 
+// CHECK-NEXT:   [[IMPLICIT:%.*]] = integer_literal $Builtin.Int1, -1
+// CHECK:   [[PRECOND:%.*]] = function_ref @$Ss30_diagnoseUnexpectedNilOptional{{[_0-9a-zA-Z]*}}F
+// CHECK:   apply [[PRECOND]]([[FILESTR]], [[FILESIZ]], [[FILEASC]], [[LINE]], [[IMPLICIT]])
 // CHECK: bb2([[UNWRAPPED_RESULT:%.*]] : @owned $Gizmo):
 // CHECK:   store [[UNWRAPPED_RESULT]] to [init] [[SELF]] : $*Gizmo