[lldb-dev] LLDB not loading any debug information on windows

[Zachary Turner via lldb-dev]

You actually can get dwarf on Windows, i made this work a long time ago
before we were able to generate PDB, while i was still porting lldb to
Windows. Since pdb wasn’t a thing at the time, dwarf was necessary in order
to get anything working.

I don’t know what the state of it is today though and I’d definitely
consider it unsupported at minimum
On Thu, Mar 14, 2019 at 5:49 AM <paul.robinson at sony.com> wrote:

> (Resend, remembering to add lldb-dev back this time)
>
> Asking for DWARF on Windows generally doesn't get you any info at all.
>
>
>
> FTR, the `-glldb` option means generate DWARF, "tuned" for LLDB.  Clang
> understands three "debugger tunings" which are gdb, lldb, and sce. The
> distinctions are minor and not relevant here.
>
> --paulr
>
>
>
>
>
> *From:* lldb-dev [mailto:lldb-dev-bounces at lists.llvm.org] *On Behalf Of *Zachary
> Turner via lldb-dev
> *Sent:* Wednesday, March 13, 2019 8:07 PM
> *To:* Adrian McCarthy
> *Cc:* LLDB
> *Subject:* Re: [lldb-dev] LLDB not loading any debug information on
> windows
>
>
>
> Two things stand out to me as odd here.
>
>
>
> 1) -glldb.  -g is supposed to specify the debug information format, either
> dwarf, codeview, or whichever is the default.  I've never heard of anyone
> using -glldb (or for that matter -ggdb).  Just -g, -gcodeview, or -gdwarf.
>
>
>
> 2) You're using clang instead of clang-cl.  While it's possible to make
> things work, we designed clang-cl specifically to avoid these kinds of
> issues, so I would first try running `clang-cl /Z7 main.c` and see if
> things suddenly start working better.
>
>
>
> To be honest, I'm surprised it's even generating a PDB at all with the
> given command line, but then again it's not a codepath anyone has really
> tested, so maybe it's generating "something".
>
>
>
> On Wed, Mar 13, 2019 at 5:01 PM Adrian McCarthy via lldb-dev <
> lldb-dev at lists.llvm.org> wrote:
>
> Sorry for the delay.  There's definitely something going wrong here.
>
>
>
> If you specify the .pdb file (target symbols add a.pdb), it iterates
> through the objfile plugins to see if any match, and none of them do
> (because a PDB file is not a "module").
>
>
>
> If you specify the .exe file (target symbols add a.exe), it matches an
> objfile plugin and creates the symbol vendor, but the symbol vendor says
> the symbol file is the .exe itself rather than the .pdb, so it appears to
> work but no symbols are actually loaded.
>
>
>
> If you specify the .exe with -s (target symbols add -s a.exe), you again
> get silent failure as in the previous case.
>
>
>
> I'll look at this some more tomorrow to see if I can figure out what this
> code path is supposed to be doing.
>
>
>
> On Mon, Mar 4, 2019 at 11:00 AM Christoph Baumann via lldb-dev <
> lldb-dev at lists.llvm.org> wrote:
>
> Hey,
>
> in order to try lldb on windows, i built (with clang compiler and lld
> linker (v7.0.1)) llvm, clang, lld and of course lldb from latest source
> with the following command line:
>
>
>
> > cmake -G Ninja -DCMAKE_C_COMPILER=clang-cl -DCMAKE_CXX_COMPILER=clang-cl
> -DCMAKE_LINKER=lld-link -DLLDB_RELOCATABLE_PYTHON=1
> -DLLDB_PYTHON_HOME=“C:\program files\python37“ -DLLVM_BUILD_TESTS=0
> -DLLVM_BUILD_BENCHMARKS=0 -DLLVM_BUILD_EXAMPLES=0
> -DCMAKE_BUILD_TYPE=Release -DLLVM_TARGET_ARCH=host
> -DCMAKE_INSTALL_PREFIX=“..\release“ ..\src\llvm
>
> >ninja install
>
>
>
> Here my little program i used to test lldb:
>
>
>
> > //main.c
>
> > #include <stdio.h>
>
> >
>
> > int a=10;
>
> >
>
> > int main(int argc, char *argv[]){
>
> >             for(int i=0;i<argc;i++){
>
> >                           printf("%s\n", argv[i]);
>
> >             }
>
> >             return(0);
>
> > }
>
>
>
> I compiled the above with „clang main.c -glldb -o a.exe“, which generated
> the executable a.exe and corresponding debug information a.pdb.
>
> I launched lldb with „lldb a.exe“ and tried to load the debug information
> with „target symbols add a.pdb“, however this resulted in „error: symbol
> file [….]\a.pdb does not match any existing module“.
>
>
>
> I am using Windows 10 pro 64bit, my both, my test program and lldb were
> compiled for x64 target.
>
>
>
> I have also tried the prebuilt llvm/lldb binaries (v8.0.0, v7.0.1) found
> on llvm.org, same result.
>
>
>
> I feel like i am missing something (unless lldb just does not work on
> windows yet).
>
>
>
> (On a sidenote, compiling with -gdwarf-5 makes clang crash. I can send the
> debug information clang spits out once my debug build finishes.)
>
>
>
> Greetings
>
>
>
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