In debugger mode, make ObjC message sends to unknown selectors return

__unknown_anytype, and rewrite such message sends correctly.

I had to bite the bullet and actually add a debugger support mode for this
one, which is a bit unfortunate, but there really isn't anything else
I could imagine doing;  this is clearly just debugger-specific behavior.

llvm-svn: 135051

clang/include/clang/Basic/LangOptions.h

@@ -119,6 +119,8 @@ public:
   unsigned InlineVisibilityHidden : 1; // Whether inline C++ methods have
                                        // hidden visibility by default.
   unsigned ParseUnknownAnytype: 1; /// Let the user write __unknown_anytype.
+  unsigned DebuggerSupport : 1;   /// Do things that only make sense when
+                                  /// supporting a debugger
 
   unsigned SpellChecking : 1; // Whether to perform spell-checking for error
                               // recovery.
@@ -241,7 +243,7 @@ public:
     FakeAddressSpaceMap = 0;
     MRTD = 0;
     DelayedTemplateParsing = 0;
-    ParseUnknownAnytype = 0;
+    ParseUnknownAnytype = DebuggerSupport = 0;
   }
 
   GCMode getGCMode() const { return (GCMode) GC; }

clang/include/clang/Driver/CC1Options.td

@@ -582,6 +582,8 @@ def fdelayed_template_parsing : Flag<"-fdelayed-template-parsing">,
            "translation unit ">;
 def funknown_anytype : Flag<"-funknown-anytype">,
   HelpText<"Enable parser support for the __unknown_anytype type; for testing purposes only">;
+def fdebugger_support : Flag<"-fdebugger-support">,
+  HelpText<"Enable special debugger support behavior">;
 def fdeprecated_macro : Flag<"-fdeprecated-macro">,
   HelpText<"Defines the __DEPRECATED macro">;
 def fno_deprecated_macro : Flag<"-fno-deprecated-macro">,

clang/lib/Frontend/CompilerInvocation.cpp

@@ -737,6 +737,8 @@ static void LangOptsToArgs(const LangOptions &Opts,
     Res.push_back("-ffake-address-space-map");
   if (Opts.ParseUnknownAnytype)
     Res.push_back("-funknown-anytype");
+  if (Opts.DebuggerSupport)
+    Res.push_back("-fdebugger-support");
   if (Opts.DelayedTemplateParsing)
     Res.push_back("-fdelayed-template-parsing");
   if (Opts.Deprecated)
@@ -1667,6 +1669,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.MRTD = Args.hasArg(OPT_mrtd);
   Opts.FakeAddressSpaceMap = Args.hasArg(OPT_ffake_address_space_map);
   Opts.ParseUnknownAnytype = Args.hasArg(OPT_funknown_anytype);
+  Opts.DebuggerSupport = Args.hasArg(OPT_fdebugger_support);
 
   // Record whether the __DEPRECATED define was requested.
   Opts.Deprecated = Args.hasFlag(OPT_fdeprecated_macro,

clang/lib/Sema/SemaExpr.cpp

@@ -9552,9 +9552,6 @@ ExprResult RebuildUnknownAnyExpr::VisitCallExpr(CallExpr *call) {
 }
 
 ExprResult RebuildUnknownAnyExpr::VisitObjCMessageExpr(ObjCMessageExpr *msg) {
-  ObjCMethodDecl *method = msg->getMethodDecl();
-  assert(method && "__unknown_anytype message without result type?");
-
   // Verify that this is a legal result type of a call.
   if (DestType->isArrayType() || DestType->isFunctionType()) {
     S.Diag(msg->getExprLoc(), diag::err_func_returning_array_function)
@@ -9562,8 +9559,11 @@ ExprResult RebuildUnknownAnyExpr::VisitObjCMessageExpr(ObjCMessageExpr *msg) {
     return ExprError();
   }
 
-  assert(method->getResultType() == S.Context.UnknownAnyTy);
-  method->setResultType(DestType);
+  // Rewrite the method result type if available.
+  if (ObjCMethodDecl *method = msg->getMethodDecl()) {
+    assert(method->getResultType() == S.Context.UnknownAnyTy);
+    method->setResultType(DestType);
+  }
 
   // Change the type of the message.
   msg->setType(DestType.getNonReferenceType());

clang/lib/Sema/SemaExprObjC.cpp

@@ -355,7 +355,14 @@ bool Sema::CheckMessageArgumentTypes(QualType ReceiverType,
                               : diag::warn_inst_method_not_found;
     Diag(lbrac, DiagID)
       << Sel << isClassMessage << SourceRange(lbrac, rbrac);
-    ReturnType = Context.getObjCIdType();
+
+    // In debuggers, we want to use __unknown_anytype for these
+    // results so that clients can cast them.
+    if (getLangOptions().DebuggerSupport) {
+      ReturnType = Context.UnknownAnyTy;
+    } else {
+      ReturnType = Context.getObjCIdType();
+    }
     VK = VK_RValue;
     return false;
   }

clang/test/SemaObjC/debugger-support.m

@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -fdebugger-support %s -emit-llvm -o - | FileCheck %s
+
+// rdar://problem/9416370
+void test0(id x) {
+  struct A { int w, x, y, z; };
+  struct A result = (struct A) [x makeStruct];
+  // CHECK:     define void @test0(
+  // CHECK:      [[X:%.*]] = alloca i8*, align 8
+  // CHECK-NEXT: [[RESULT:%.*]] = alloca [[A:%.*]], align 4
+  // CHECK-NEXT: store i8* {{%.*}}, i8** [[X]],
+  // CHECK-NEXT: [[T0:%.*]] = load i8** [[X]],
+  // CHECK-NEXT: [[T1:%.*]] = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_"
+  // CHECK-NEXT: [[T2:%.*]] = call { i64, i64 } bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to { i64, i64 } (i8*, i8*)*)(i8* [[T0]], i8* [[T1]])
+}