Clang has existing support for debuggers that

want to provide "po"-like functionality which
treats the result of an expression implicitly as
"id" (if it is not otherwise known) and prints
it as an Objective-C object.

This has in the past been gated by the
"DebuggerSupport" language option, but that is
too general.  Debuggers also provide other commands
like "print" that do not make any assumptions
about whether the object is an Objective-C object.

This patch makes the assumption conditional on a
new language option: DebuggerCastResultToId.  I
have also made corresponding modifications to the
testsuite.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149735 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Basic/LangOptions.def

@@ -123,6 +123,7 @@ LANGOPT(NoConstantCFStrings , 1, 0, "no constant CoreFoundation strings")
 BENIGN_LANGOPT(InlineVisibilityHidden , 1, 0, "hidden default visibility for inline C++ methods")
 BENIGN_LANGOPT(ParseUnknownAnytype, 1, 0, "__unknown_anytype")
 BENIGN_LANGOPT(DebuggerSupport , 1, 0, "debugger support")
+BENIGN_LANGOPT(DebuggerCastResultToId, 1, 0, "for 'po' in the debugger, cast the result to id if it is of unknown type")
 BENIGN_LANGOPT(AddressSanitizer , 1, 0, "AddressSanitizer enabled")
 
 BENIGN_LANGOPT(SpellChecking , 1, 1, "spell-checking")

include/clang/Driver/CC1Options.td

@@ -651,6 +651,8 @@ 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 fdebugger_cast_result_to_id : Flag<"-fdebugger-cast-result-to-id">,
+  HelpText<"Enable casting unknown expression results to id">;
 def fdeprecated_macro : Flag<"-fdeprecated-macro">,
   HelpText<"Defines the __DEPRECATED macro">;
 def fno_deprecated_macro : Flag<"-fno-deprecated-macro">,

lib/Frontend/CompilerInvocation.cpp

@@ -826,6 +826,8 @@ static void LangOptsToArgs(const LangOptions &Opts,
     Res.push_back("-funknown-anytype");
   if (Opts.DebuggerSupport)
     Res.push_back("-fdebugger-support");
+  if (Opts.DebuggerCastResultToId)
+    Res.push_back("-fdebugger-cast-result-to-id");
   if (Opts.DelayedTemplateParsing)
     Res.push_back("-fdelayed-template-parsing");
   if (Opts.Deprecated)
@@ -1885,6 +1887,7 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
   Opts.FakeAddressSpaceMap = Args.hasArg(OPT_ffake_address_space_map);
   Opts.ParseUnknownAnytype = Args.hasArg(OPT_funknown_anytype);
   Opts.DebuggerSupport = Args.hasArg(OPT_fdebugger_support);
+  Opts.DebuggerCastResultToId = Args.hasArg(OPT_fdebugger_cast_result_to_id);
   Opts.AddressSanitizer = Args.hasArg(OPT_faddress_sanitizer);
   Opts.ApplePragmaPack = Args.hasArg(OPT_fapple_pragma_pack);
   Opts.CurrentModule = Args.getLastArgValue(OPT_fmodule_name);

lib/Sema/SemaExprCXX.cpp

@@ -4767,7 +4767,7 @@ ExprResult Sema::ActOnFinishFullExpr(Expr *FE) {
     return ExprError();
 
   // Top-level message sends default to 'id' when we're in a debugger.
-  if (getLangOptions().DebuggerSupport &&
+  if (getLangOptions().DebuggerCastResultToId &&
       FullExpr.get()->getType() == Context.UnknownAnyTy &&
       isa<ObjCMessageExpr>(FullExpr.get())) {
     FullExpr = forceUnknownAnyToType(FullExpr.take(), Context.getObjCIdType());

test/SemaObjC/debugger-cast-result-to-id.m

@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 -funknown-anytype -fsyntax-only -fdebugger-support -fdebugger-cast-result-to-id -verify %s
+
+extern __unknown_anytype test0;
+extern __unknown_anytype test1();
+
+void test_unknown_anytype_receiver() {
+  (void)(int)[[test0 unknownMethod] otherUnknownMethod];;
+  (void)(id)[[test1() unknownMethod] otherUnknownMethod];
+}
+// RUN: %clang_cc1 -funknown-anytype -fsyntax-only -fdebugger-support -fdebugger-cast-result-to-id -verify %s
+
+extern __unknown_anytype test0;
+extern __unknown_anytype test1();
+
+void test_unknown_anytype_receiver() {
+  (void)(int)[[test0 unknownMethod] otherUnknownMethod];;
+  (void)(id)[[test1() unknownMethod] otherUnknownMethod];
+}
+// RUN: %clang_cc1 -funknown-anytype -fsyntax-only -fdebugger-support -fdebugger-cast-result-to-id -verify %s
+
+extern __unknown_anytype test0;
+extern __unknown_anytype test1();
+
+void test_unknown_anytype_receiver() {
+  (void)(int)[[test0 unknownMethod] otherUnknownMethod];;
+  (void)(id)[[test1() unknownMethod] otherUnknownMethod];
+}

test/SemaObjC/unknown-anytype.m

@@ -17,9 +17,9 @@ void test_unknown_anytype_receiver() {
   int *ip = [test0 getIntPtr];
   float *fp = [test1() getFloatPtr];
   double *dp = [test1() getSomePtr]; // okay: picks first method found
-  [[test0 unknownMethod] otherUnknownMethod]; 
+  [[test0 unknownMethod] otherUnknownMethod]; // expected-error{{no known method '-otherUnknownMethod'; cast the message send to the method's return type}}
   (void)(int)[[test0 unknownMethod] otherUnknownMethod];;
-  [[test1() unknownMethod] otherUnknownMethod];
+  [[test1() unknownMethod] otherUnknownMethod]; // expected-error{{no known method '-otherUnknownMethod'; cast the message send to the method's return type}}
   (void)(id)[[test1() unknownMethod] otherUnknownMethod];
 
   if ([[test0 unknownMethod] otherUnknownMethod]) { // expected-error{{no known method '-otherUnknownMethod'; cast the message send to the method's return type}}