https://llvm.org/bugs/show_bug.cgi?id=24344
Bug ID: 24344 Summary: Objective-C++ to C++ Rewriter produces ill-formed C++11 code Product: clang Version: unspecified Hardware: PC OS: Windows NT Status: NEW Severity: normal Priority: P Component: -New Bugs Assignee: unassignedclangb...@nondot.org Reporter: charles...@playstation.sony.com CC: llvmbugs@cs.uiuc.edu Classification: Unclassified Hello Clang developers, I came across this bug when running Clang lit tests on test/Rewriter folder with the default C++ standard dialect set to C++11. When I ran the test, 32 tests failed. The list is appended to the bottom. It appears that when rewriting Objective-C++ to C++, the rewriter will always generate C++03 code, even when -std=C++11 mode is requested. Here is a reduced test case: /*************************************************/ @interface Foo { int a; } @end @implementation Foo static void foo() { } @end /*************************************************/ Rewriting this test to C++ then Compiling the C++ code produces the following. $clang -cc1 -x objective-c++ -fms-extensions -rewrite-objc -fobjc-runtime=macosx-fragile-10.5 t.mm -o t_gen.cpp -std=c++11 $clang -cc1 -Did="void*" -D"SEL=void*" -D"__declspec(X)=" t_gen.cpp -std=c++11 t_gen.cpp:104:5: warning: ISO C++11 does not allow conversion from string literal to 'char *' ,{{"a", "i", __OFFSETOFIVAR__(struct Foo_IMPL, a)} ^ t_gen.cpp:104:10: warning: ISO C++11 does not allow conversion from string literal to 'char *' ,{{"a", "i", __OFFSETOFIVAR__(struct Foo_IMPL, a)} ^ t_gen.cpp:104:15: error: non-constant-expression cannot be narrowed from type 'long long' to 'int' in initializer list ,{{"a", "i", __OFFSETOFIVAR__(struct Foo_IMPL, a)} ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ t_gen.cpp:77:40: note: expanded from macro '__OFFSETOFIVAR__' #define __OFFSETOFIVAR__(TYPE, MEMBER) ((long long) &((TYPE *)0)->MEMBER) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ t_gen.cpp:104:15: note: insert an explicit cast to silence this issue ,{{"a", "i", __OFFSETOFIVAR__(struct Foo_IMPL, a)} ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ static_cast<int>( ) t_gen.cpp:77:40: note: expanded from macro '__OFFSETOFIVAR__' #define __OFFSETOFIVAR__(TYPE, MEMBER) ((long long) &((TYPE *)0)->MEMBER) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ t_gen.cpp:124:34: warning: ISO C++11 does not allow conversion from string literal to 'char *' (struct _objc_class *)"Foo", 0, "Foo", 0,2, sizeof(struct _objc_class), 0, 0 ^ t_gen.cpp:129:27: warning: ISO C++11 does not allow conversion from string literal to 'char *' &_OBJC_METACLASS_Foo, 0, "Foo", 0,1,sizeof(struct Foo_IMPL), (struct _objc_ivar_list *)&_OBJC_INSTANCE_VARIABLES_Foo ^ 4 warnings and 1 error generated. I noticed in the generated C++ file, macro __OFFSETOFIVAR__ returns type “long long”. While the value being initialized is “int ivar_offset”. /*****************************************************************/ #define __OFFSETOFIVAR__(TYPE, MEMBER) ((long long) &((TYPE *)0)->MEMBER) struct _objc_ivar { char *ivar_name; char *ivar_type; int ivar_offset; }; static struct { int ivar_count; struct _objc_ivar ivar_list[1]; } _OBJC_INSTANCE_VARIABLES_Foo __attribute__ ((used, section ("__OBJC, __instance_vars")))= { 1 ,{{"a", "i", __OFFSETOFIVAR__(struct Foo_IMPL, a)} } }; /*****************************************************************/ Narrowing conversion inside an initializer list is unfortunately ill-form in C++11 per [dcl.init.aggr] and [dcl.init.list]. Here is the full list of Clang Lit failures in the Rewriter folder that fail due to the same reason. Failing Tests (32): Clang :: Rewriter/modern-write-bf-abi.mm Clang :: Rewriter/objc-modern-property-bitfield.m Clang :: Rewriter/property-dot-syntax.mm Clang :: Rewriter/rewrite-block-literal-1.mm Clang :: Rewriter/rewrite-block-pointer.mm Clang :: Rewriter/rewrite-byref-in-nested-blocks.mm Clang :: Rewriter/rewrite-byref-vars.mm Clang :: Rewriter/rewrite-cast-ivar-modern-access.mm Clang :: Rewriter/rewrite-elaborated-type.mm Clang :: Rewriter/rewrite-foreach-in-block.mm Clang :: Rewriter/rewrite-foreach-protocol-id.m Clang :: Rewriter/rewrite-forward-class.m Clang :: Rewriter/rewrite-forward-class.mm Clang :: Rewriter/rewrite-ivar-use.m Clang :: Rewriter/rewrite-modern-atautoreleasepool.mm Clang :: Rewriter/rewrite-modern-block-ivar-call.mm Clang :: Rewriter/rewrite-modern-class.mm Clang :: Rewriter/rewrite-modern-default-property-synthesis.mm Clang :: Rewriter/rewrite-modern-extern-c-func-decl.mm Clang :: Rewriter/rewrite-modern-ivar-use.mm Clang :: Rewriter/rewrite-modern-ivars-2.mm Clang :: Rewriter/rewrite-modern-ivars.mm Clang :: Rewriter/rewrite-modern-nested-ivar.mm Clang :: Rewriter/rewrite-modern-throw.m Clang :: Rewriter/rewrite-nested-blocks-1.mm Clang :: Rewriter/rewrite-nested-blocks.mm Clang :: Rewriter/rewrite-nested-ivar.mm Clang :: Rewriter/rewrite-property-attributes.mm Clang :: Rewriter/rewrite-property-set-cfstring.mm Clang :: Rewriter/rewrite-protocol-property.mm Clang :: Rewriter/rewrite-user-defined-accessors.mm Clang :: Rewriter/rewrite-vararg.m Expected Passes : 112 Unexpected Failures: 32 -- You are receiving this mail because: You are on the CC list for the bug.
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