C++ Issue on GCC 3.0 branch

[Mark Mitchell]

>>>>> "John" == John David Anglin <dave@hiauly1.hia.nrc.ca> writes:

    John> While I am certain that the patch eliminates the duplicate
    John> symbols, I am still concerned that assemble_external is
    John> being called with TREE_PUBLIC and DECL_EXTERNAL set for the
    John> type declarations.  This causes .IMPORT statements to be

Yes, that's why I asked about this.

There's a basic problem here; both the C and C++ front-ends call
assemble_external in a way that is inconsistent with the
assemble_external documentation.

In particular, ASM_OUTPUT_EXTERNAL is documented as used when
something is 

     A C statement (sans semicolon) to output to the stdio stream
     STREAM any text necessary for declaring the name of an external
     symbol named NAME which is referenced in this compilation but not
     defined.  The value of DECL is the tree node for the declaration.

You can't know this until the end of the translation unit.  But, we
compile a function-at-a-time, so if we see:

  extern void f(); 
  void g() { f(); }
  void f() {}

we call this macro for `f'.

It's even more extreme in C++ because we don't make up our minds about
the linkages of some functions until very late in the game.  (See the
tricks played with DECL_NOT_REALLY_EXTERN.)  That's all really pretty
grotesque, but it's not easy to fix, and it's been that way for a long
time, so I'm guessing most systems deal with it OK.

--
Mark Mitchell                   mark@codesourcery.com
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