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digitalmars.D.bugs - [Issue 5748] New: naked annotation

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=5748

           Summary:  naked annotation
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: bearophile_hugs eml.cc



I think that the "naked" that currently is usable inside asm blocks is a
property of the whole function that contains the asm block and not just of the
asm block, so I suggest to deprecate (and later remove) the "naked" and to add
a  naked function annotation.

An example, from (from dmd\src\druntime\src\core\thread.d):


version( D_InlineAsm_X86 ) {
    static void* getBasePtr() {
        asm {
            naked;
            mov EAX, EBP;
            ret;
        }
    }

    obj.m_main.bstack = getBasePtr();
} else version( D_InlineAsm_X86_64 ) {
    static void* getBasePtr() {
        asm {
            naked;
            mov RAX, RBP;
            ret;
        }
    }

    obj.m_main.bstack = getBasePtr();
}


To:

version( D_InlineAsm_X86 ) {
     naked static void* getBasePtr() {
        asm {
            mov EAX, EBP;
            ret;
        }
    }

    obj.m_main.bstack = getBasePtr();
} else version( D_InlineAsm_X86_64 ) {
     naked static void* getBasePtr() {
        asm {
            mov RAX, RBP;
            ret;
        }
    }

    obj.m_main.bstack = getBasePtr();
}

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next sibling parent d-bugmail puremagic.com writes:
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Walter Bright <bugzilla digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla digitalmars.com
         Resolution|                            |WONTFIX



11:21:28 PDT ---
naked is not a property of the function's interface, and therefore should
properly not be part of its declaration.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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Max Samukha <samukha voliacable.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |samukha voliacable.com



PDT ---
Should an attribute be necessarily part of function interface? MSVC uses
__declspec(naked), which is not part of the function interface
(http://msdn.microsoft.com/en-us/library/h5w10wxs%28v=vs.80%29.aspx). Also, the
GNU compiler uses __attribute__((naked)). Having "naked" in the assembly block
has never felt right, really.

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16:04:04 PDT ---


 Should an attribute be necessarily part of function interface? MSVC uses
 __declspec(naked), which is not part of the function interface
 (http://msdn.microsoft.com/en-us/library/h5w10wxs%28v=vs.80%29.aspx). Also, the
 GNU compiler uses __attribute__((naked)). Having "naked" in the assembly block
 has never felt right, really.


Naked is an internal characteristic of a function, not an external one. It
simply does not belong in the declaration, despite the existence of poorly
designed extensions in other languages.

Think of it this way - is it a good design to have to change your header files
if you change your implementation?

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PDT ---


 I think that the "naked" that currently is usable inside asm blocks is a
 property of the whole function that contains the asm block and not just of the
 asm block, so I suggest to deprecate (and later remove) the "naked" and to add
 a  naked function annotation.
 
 An example, from (from dmd\src\druntime\src\core\thread.d):
 
 
 version( D_InlineAsm_X86 ) {
     static void* getBasePtr() {
         asm {
             naked;
             mov EAX, EBP;
             ret;
         }
     }
 
     obj.m_main.bstack = getBasePtr();
 } else version( D_InlineAsm_X86_64 ) {
     static void* getBasePtr() {
         asm {
             naked;
             mov RAX, RBP;
             ret;
         }
     }
 
     obj.m_main.bstack = getBasePtr();
 }
 
 
 To:
 
 version( D_InlineAsm_X86 ) {
      naked static void* getBasePtr() {
         asm {
             mov EAX, EBP;
             ret;
         }
     }
 
     obj.m_main.bstack = getBasePtr();
 } else version( D_InlineAsm_X86_64 ) {
      naked static void* getBasePtr() {
         asm {
             mov RAX, RBP;
             ret;
         }
     }
 
     obj.m_main.bstack = getBasePtr();
 }






 Should an attribute be necessarily part of function interface? MSVC uses
 __declspec(naked), which is not part of the function interface
 (http://msdn.microsoft.com/en-us/library/h5w10wxs%28v=vs.80%29.aspx). Also, the
 GNU compiler uses __attribute__((naked)). Having "naked" in the assembly block
 has never felt right, really.


 
 Naked is an internal characteristic of a function, not an external one. It
 simply does not belong in the declaration, despite the existence of poorly
 designed extensions in other languages.
 


But it is still a function characteristic and it definitely doesn't belong in
the assembly block, so I think "poorly designed" applies to D as well.


 Think of it this way - is it a good design to have to change your header files
 if you change your implementation?


You do not need to change header files with MSVC because the attribute is
permitted only in the function definition.

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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01:04:49 PDT ---


 Naked is an internal characteristic of a function, not an external one. It
 simply does not belong in the declaration, despite the existence of poorly
 designed extensions in other languages.
 


 But it is still a function characteristic


Internal only. It is not externally visible and simply does not logically
belong in the description of the external interface.


 and it definitely doesn't belong in
 the assembly block, so I think "poorly designed" applies to D as well.


Naked only makes sense if you have inline assembly, so physically associating
it with that makes sense. There is no obvious syntax for it, but putting it in
the function's external interface is just wrong.


 Think of it this way - is it a good design to have to change your header files
 if you change your implementation?


 You do not need to change header files with MSVC because the attribute is
 permitted only in the function definition.


Sorry, but major yuk to that :-)

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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PDT ---




 Naked is an internal characteristic of a function, not an external one. It
 simply does not belong in the declaration, despite the existence of poorly
 designed extensions in other languages.
 


 But it is still a function characteristic


 
 Internal only. It is not externally visible and simply does not logically
 belong in the description of the external interface.
 

 and it definitely doesn't belong in
 the assembly block, so I think "poorly designed" applies to D as well.


 
 Naked only makes sense if you have inline assembly, so physically associating
 it with that makes sense. There is no obvious syntax for it, but putting it in
 the function's external interface is just wrong.


Only if you think about function attributes as attributes of the function's
interface.


 

 Think of it this way - is it a good design to have to change your header files
 if you change your implementation?


 You do not need to change header files with MSVC because the attribute is
 permitted only in the function definition.


 
 Sorry, but major yuk to that :-)


Maybe, you are right. Minor issue, anyway. Doesn't deserve a major yuk.

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Don <clugdbug yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |clugdbug yahoo.com.au



Somewhat related is the Pervert Bug: (bug 2350).
Really, the compiler should be a lot stricter on what it allows inside a naked
function. IMHO, the main reason people feel that there's a need for annotation,
is that DMD currently allows a lot of garbage to compile. If the compiler were
adequately strict, it'd be clear it was an asm-only issue.

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