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

[Zachary Turner via lldb-dev]

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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>>
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