[Iverilog-devel] MSYS2 installation

[Evan L. <sa2...@cy...>]

Some feedback on an MSYS2/mingw64 build (a 64-bit build, with the newer 
version of MinGW). This is pretty painless, except that 'make install' 
doesn't work. There are various warnings with the gcc 9.1.0 build, but 
nothing important - I can post the build output if anyone wants to see 
it. Note that this is a clean MSYS2 build, and not a Cygwin build.

The generated Makefile appears to be incorrect for the install step, but 
I'm not quite sure how. The 'install' goal depends on 'all', and make 
runs through the 'all' dependencies before starting the install step. It 
gets to the Bison rule, and decides that parse.h is out of date, because 
it's older than parse.cc. It then attempts to carry out the 'mv 
parse.cc.h', but fails, since parse.cc.h no longer exists, having 
already been moved in the main build. This happens in 3 different 
Makefiles. The comment here refers to 'pr3462585' to explain why the 
Bison rule is carried out this way, but I can't find anything on 
pr3462585 on the net.

parse.h and parse.cc actually have the same (visible) timestamp so, at 
first sight, this shouldn't happen. My first thought was that it might 
be a time resolution problem on Win/MSYS2, so I added 
.LOW_RESOLUTION_TIME targets with parse.h prerequisites, but this does 
nothing (and make complains that they're high resolution anyway). I also 
tried running the install step with the Cygwin make rather than the 
MSYS2 make, but this makes no difference (and would probably fail anyway).

The manual fix is simply to touch the parse.h files when the build 
stops, and re-run the install.

The next issue is that the build is dynamic, and I don't think this 
really works for Windows. To get iverilog to run, you have to ship 
MinGW's libstdc++-6.dll, libgcc_s_seh-1.dll, and libwinpthread-1.dll 
with iverilog. You can just put them in the same bin directory. But, to 
get vvp to run, you have to add lots more dlls (not sure which). The 
simplest thing to do is just to install MSYS2 with either the 32-bit or 
64-bit toolchain, and put the toolchain in your path 
(/cygdrive/c/msys64/mingw64/bin for me, in my Cygwin path) along with 
the MSYS2-generated Icarus exes. Not great, and Pablo's installer gives 
you an option to install the required DLLs. It doesn't work without the 
DLLs, so presumably this option is for people who already have an MSYS2 
installation.

None of this is necessary with a static build, which is what I do with 
my own code. However, that's with hand-written Makefiles, and I'm not 
sure how to persuade configure to generate static binaries, or even if 
it's possible.