Re: windows static archive, missing symbols

[Brian Dessent]

Howard Chu wrote:

> That's false. It's just an address relocation, performed by the runtime
> linker. Writing code that requires XXX_STATIC macros is nothing but
> ignorant, and hasn't been necessary for at least 5 years.

You know I did actually test this before posting.  Go on, do a hello
world that calls a dllimported function.  Here is the testcase I used:

#include <stdio.h>

void foo(void);

int main()
{
  puts("main");
  foo();
}

Without any __declspec on the declaration to foo, the disassembly in the
debugger is:

6       {
0x401050        <main>:         push   %ebp
0x401051        <main+1>:               mov    $0x10,%eax
0x401056        <main+6>:               mov    %esp,%ebp
0x401058        <main+8>:               sub    $0x8,%esp
0x40105b        <main+11>:              and    $0xfffffff0,%esp
0x40105e        <main+14>:              call   0x401090 <_alloca>
0x401063        <main+19>:              call   0x401120 <__main>
7         puts("main");
0x401068        <main+24>:              movl   $0x402000,(%esp)
0x40106f        <main+31>:              call   0x401130 <puts>
8         foo();
0x401074        <main+36>:              call   0x401080 <foo>
9       }
0x401079        <main+41>:              leave  
0x40107a        <main+42>:              ret    

And note that 0x401080 <foo> is the import stub that calls __imp_foo:

0x401080        <foo>:          jmp    *0x404098

Now, add the __declspec(dllimport) and recompile.  This is what you get
now:

6       {
0x401050        <main>:         push   %ebp
0x401051        <main+1>:               mov    $0x10,%eax
0x401056        <main+6>:               mov    %esp,%ebp
0x401058        <main+8>:               sub    $0x8,%esp
0x40105b        <main+11>:              and    $0xfffffff0,%esp
0x40105e        <main+14>:              call   0x401090 <_alloca>
0x401063        <main+19>:              call   0x401120 <__main>
7         puts("main");
0x401068        <main+24>:              movl   $0x402000,(%esp)
0x40106f        <main+31>:              call   0x401130 <puts>
8         foo();
0x401074        <main+36>:              call   *0x404098
9       }
0x40107a        <main+42>:              leave  
0x40107b        <main+43>:              ret    

Note that here you get a direct call to the .idata location of the
imported address (__imp_foo aka 0x0404098) without the extra call.

So, no, it is not the same to omit dllimport, there is a (small) speed
penalty.  And there was recently a patch posted and applied to binutils
that will eliminate these stubs if they are not necessary so once you
upgrade your binutils there will be a size penalty to not using
dllimport also.

Brian