On Sun, 13 Feb 2011 14:12:02 -0500, Walter Bright
<[email protected]> wrote:
Vladimir Panteleev wrote:
On Sun, 13 Feb 2011 20:26:50 +0200, Walter Bright
<[email protected]> wrote:
golgeliyele wrote:
I don't think C++ and gcc set a good bar here.
Short of writing our own linker, we're a bit stuck with what ld does.
That's not true. The compiler has knowledge of what symbols will be
passed to the linker, and can display its own, much nicer error
messages. I've mentioned this in our previous discussion on this topic.
Not without reading the .o files passed to the linker, and the
libraries, and figuring out what would be pulled in from those
libraries. In essence, the compiler would have to become a linker.
It's not impossible, but is a tremendous amount of work in order to
improve one error message, and one error message that generations of C
and C++ programmers are comfortable dealing with.
I'm not saying that this should be done and is worth the tremendous effort.
However, when linking a c++ app without a main, here is what I get:
/usr/lib/gcc/i686-linux-gnu/4.4.5/../../../../lib/crt1.o: In function
`_start':
(.text+0x18): undefined reference to `main'
When linking a d app without a main, we get:
/home/steves/dmd-2.051/linux/bin/../lib/libphobos2.a(dmain2_517_1a5.o): In
function `_D2rt6dmain24mainUiPPaZi7runMainMFZv':
src/rt/dmain2.d:(.text._D2rt6dmain24mainUiPPaZi7runMainMFZv+0x16):
undefined reference to `_Dmain'
/home/steves/dmd-2.051/linux/bin/../lib/libphobos2.a(deh2_4e7_525.o): In
function `_D2rt4deh213__eh_finddataFPvZPS2rt4deh213DHandlerTable':
src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh213DHandlerTable+0x4):
undefined reference to `_deh_beg'
src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh213DHandlerTable+0xc):
undefined reference to `_deh_beg'
src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh213DHandlerTable+0x13):
undefined reference to `_deh_end'
src/rt/deh2.d:(.text._D2rt4deh213__eh_finddataFPvZPS2rt4deh213DHandlerTable+0x37):
undefined reference to `_deh_end'
/home/steves/dmd-2.051/linux/bin/../lib/libphobos2.a(thread_eb_258.o): In
function `_D4core6thread6Thread6__ctorMFZC4core6thread6Thread':
src/core/thread.d:(.text._D4core6thread6Thread6__ctorMFZC4core6thread6Thread+0x1d):
undefined reference to `_tlsend'
src/core/thread.d:(.text._D4core6thread6Thread6__ctorMFZC4core6thread6Thread+0x24):
undefined reference to `_tlsstart'
/home/steves/dmd-2.051/linux/bin/../lib/libphobos2.a(thread_ee_6e4.o): In
function `thread_attachThis':
src/core/thread.d:(.text.thread_attachThis+0x53): undefined reference to
`_tlsstart'
src/core/thread.d:(.text.thread_attachThis+0x5c): undefined reference to
`_tlsend'
/home/steves/dmd-2.051/linux/bin/../lib/libphobos2.a(thread_e8_713.o): In
function `thread_entryPoint':
src/core/thread.d:(.text.thread_entryPoint+0x29): undefined reference to
`_tlsend'
src/core/thread.d:(.text.thread_entryPoint+0x2f): undefined reference to
`_tlsstart'
collect2: ld returned 1 exit status
--- errorlevel 1
Let's not pretend that generations of c/C++ coders are going to attribute
this slew of errors to a missing main function. The first time I see
this, I'm going to think I missed something else.
I understand that to fix this, we need the linker to be more helpful, or
we need to make dmd more helpful. I don't know how much effort it is, or
how much it's worth it, I just wanted to point out that your statement
about equivalence to C++ is stretching it.
I personally think we need to get the linker to demangle symbols better.
That would go a long way...
-Steve
