DLL silently ignored even though the library links - dll

Question

I'm using a third part DLL that I've used successfully for ages. Now the linker links the dll lib without complaint but the exe doesn't load the dll.
I recently upgraded from the 32 bit to 64 bit cygwin.
I'm doing a mingw cross compile to 32 bits.
I'm trying to use the FTDI USB interface FTD2XX dll.
I have the version 2.04.06 FTD2XX lib, .h, and dll.
I had been using that dll successfully for ages but with older versions of cygwin and mingw.
Recently upgraded to cygwin64.
The app appears to link with the FTD2XX.lib without complaint.
But when I run the app it doesn't seem to look for or load the FTD2XX.dll.
The app runs but crashes as soon as it tries to call something in FTD2XX dll.
I created a simple hello_dll.dll for side by side test. That works.
The app.c does calls on both hello_dll.dll and ftd2xx.dll.
Is starts without complain, successfully calls function in hello_dll, and then it crashes on a call to ft2xx.dll.
(I renamed the lib to ftd2xx_2.04.06 to distinguish them from other versions I have. Newer versions don't work any better.)
Link with -verbose gives:
i686-w64-mingw32-gcc -Wall -m32 -g -O2 -c -I . -o app.o app.c
i686-w64-mingw32-gcc -Wall -m32 -o app.exe app.o -Wl,-verbose -L. -lhello_dll -lftd2xx_2.04.06
GNU ld (GNU Binutils) 2.34.50.20200227
Supported emulations:
i386pe
using internal linker script:
<snip>
/usr/lib/gcc/i686-w64-mingw32/9.2.0/../../../../i686-w64-mingw32/bin/ld: mode i386pe
attempt to open /usr/i686-w64-mingw32/sys-root/mingw/lib/../lib/crt2.o succeeded
/usr/i686-w64-mingw32/sys-root/mingw/lib/../lib/crt2.o
attempt to open /usr/lib/gcc/i686-w64-mingw32/9.2.0/crtbegin.o succeeded
/usr/lib/gcc/i686-w64-mingw32/9.2.0/crtbegin.o
attempt to open app.o succeeded
app.o
<snip>
attempt to open ./hello_dll.lib succeeded
./hello_dll.lib
(./hello_dll.lib)d000001.o
(./hello_dll.lib)d000000.o
(./hello_dll.lib)d000002.o
<snip>
attempt to open ./ftd2xx_2.04.06.lib succeeded
./ftd2xx_2.04.06.lib
(./ftd2xx_2.04.06.lib)FTD2XX.dll
(./ftd2xx_2.04.06.lib)FTD2XX.dll
(./ftd2xx_2.04.06.lib)FTD2XX.dll
(./ftd2xx_2.04.06.lib)FTD2XX.dll
::::::::::::::::::::::::::::
I obtained a 32 bit compatible version of gdb. When I run gdb:
GNU gdb (GDB) 7.7.50.20140303-cvs
<snip>
This GDB was configured as "i686-pc-mingw32".
<snip>
(gdb) break main
(gdb) Breakpoint 1 at 0x40267b: file app.c, line 28.
(gdb) run
(gdb) Starting program: C:\_d\aaa\pd\src\dll\pathological\app.exe
[New Thread 1428.0x2528]
Breakpoint 1, main (argc=1, argv=0x9b2f70) at app.c:28
28 dostuff();
(gdb) info share
(gdb) From To Syms Read Shared Object Library
0x774e0000 0x77644ccc Yes (*) C:\Windows\SysWOW64\ntdll.dll
0x753d0000 0x754cadec Yes (*) C:\Windows\syswow64\kernel32.dll
0x75ea1000 0x75ee6a3a Yes (*) C:\Windows\syswow64\KernelBase.dll
0x64081000 0x6408a1d8 Yes C:\_d\aaa\pd\src\dll\pathological\hello_dll.dll
0x75041000 0x750eb2c4 Yes (*) C:\Windows\syswow64\msvcrt.dll
(*): Shared library is missing debugging information.
(gdb) A debugging session is active.
(gdb) c
Continuing.
Hello dll. <--- The function in hello_dll.dll prints this.
Program received signal SIGSEGV, Segmentation fault.
0x8000004c in ?? () <----- call to FT_GetLibraryVersion()
(gdb) bt
#0 0x8000004c in ?? ()
#1 0x0040158e in dostuff () at app.c:49
#2 0x00402680 in main (argc=1, argv=0x8e2f70) at app.c:28
(gdb)
It links with the lib without complaint but when I run the exe it (silently) doesn't load the dll.
Anybody have any ideas? Is there some linker control that I am missing? Are there other diagnostic or debug tools to dig into this further?
:::::::::::::::::::::::
edit 7/11/20
I'll post some code. (If I know how. I'm new here.)
It should be shown in the "info share", but it isn't, as you can see above.
I'm suspecting name decoration. Objdump -x of the .exe shows an entry for FTD2XX.dll in the Import Tables. But it doesn't show any vma or bound name under it. I suspect that at program load the loader sees no vma/name and decides it doesn't really need to load the dll.
There is an import table in .idata at 0x406000
<snip>
The Import Tables (interpreted .idata section contents)
vma: Hint Time Forward DLL First
Table Stamp Chain Name Thunk
00006000 0000607c 00000000 00000000 00006218 0000614c
DLL Name: FTD2XX.dll
vma: Hint/Ord Member-Name Bound-To
<----- empty?
00006014 00006080 00000000 00000000 000064f8 00006150
DLL Name: hello_dll.dll
vma: Hint/Ord Member-Name Bound-To
6224 1 hello_dll
00006028 00006088 00000000 00000000 00006554 00006158
DLL Name: KERNEL32.dll
vma: Hint/Ord Member-Name Bound-To
6230 277 DeleteCriticalSection
6248 310 EnterCriticalSection
<snip>
:::::::::::::::::::::::::::::::::::::::::::::
edit 2, 7/11/20
This is the program that calls functions in the DLLs.
/* app.c
Demonstrates using the function imported from the DLL.
*/
// 200708 pathological case. Based on the simple hello_dll.
//#include <stdlib.h>
// for sleep
#include <unistd.h>
#include <stdio.h>
// for dword
#include <windef.h>
// for lpoverlapped
#include <minwinbase.h>
#include "hello_dll.h"
// My legacy app, and really all others too, use 2.04.06.h
#include "ftd2xx_2.04.06.h"
//#include "ftd2xx_2.02.04.h"
///////////////////////////
void dostuff( void );
void call_ft_listdevices( void );
///////////////////////////
int main(int argc, char** argv)
{
FT_STATUS status;
DWORD libver;
//dostuff();
printf( "Calling hello_dll():\n" );
fflush( stdout );
hello_dll();
fflush( stdout );
printf( "Back from hello_dll()\n" );
fflush( stdout );
sleep( 1 );
printf( "Calling FT_GetLibraryVersion().\n" );
fflush( stdout );
status = FT_GetLibraryVersion( &libver );
if( status == FT_OK ){
printf( "FTD2XX library version 0x%lx\n", libver );
fflush( stdout );
}
else{
printf( "Error reading FTD2XX library version.\n" );
fflush( stdout );
}
// 200710 Adding call to different ft function did
// not result in entries in the import table.
//call_ft_listdevices( );
return 0;
}
I don't think there is a need to include the code for my hello_dll. It works.
I have three versions of the FTD2XX. I'm pretty careful about tracking versions. Plus, when one is beating one's head against the wall, double checking the versions appeals early on as a way to end the pain.
I found a surprise copy of FTD2XX.dll. It's in c:/Windows/SysWOW64. It is the oldest of the three versions I have. Versions of my app that were compiled before this problem started run correctly using that dll in that place.

Answer 1

Solved.
There's a bug in the 2.34.50.20200227 i686-w64-mingw32-ld.exe. It won't work with ftd2xx.lib, regardless of ftd2xx version as far as I can tell.
2.25.51.20150320 and 2.29.1.20171006 work with ftd2xx.lib. I've reverted back to 2.29 mingw64-i686-binutils. I'm running again.