[llvm-dev] Debug information with clang-cl on Windows (original) (raw)

Tobias Hieta via llvm-dev llvm-dev at lists.llvm.org
Tue Mar 9 00:37:31 PST 2021

Hello,

We recently switched our windows builds from the CL compiler to clang-cl. This was a pretty big jump in terms of code generation and having a uniform compiler across all the major platforms.

Our setup is that our Windows developer use MSVC as the IDE and compile with our own build of clang-cl and link with lld-link.

Some of the developers noticed that some of the debug information are not as good as with CL. Or rather some variables seems to be optimized out, this is what the IDE says, see attached screenshot. I have tried to figure out if there is a rhyme and reason to what variables are gone - but I have not been able to see any pattern.

Our command line is:

clang-cl.exe /nologo -DUNICODE -DUSE_BREAKPAD -DWIN32 -DWIN32_LEAN_AND_MEAN -DWINVER=0x0601 -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_LEGACY_NAT_TRAVERSAL_ -D_REENTRANT -D_SCL_SECURE_NO_WARNINGS -D_SILENCE_ALL_CXX17_DEPRECATION_WARNINGS -D_UNICODE -D_WIN32_WINNT=0x0601 -D_WINSOCK_DEPRECATED_NO_WARNINGS -Iincludes -m32 -fdiagnostics-absolute-paths --target=i686-windows-msvc -m32 /DWIN32 /D_WINDOWS /GR /EHsc /Zi /Ob0 /Od /RTC1 -MDd /Zm512 /EHsc /bigobj /W3 -Werror -Wsign-compare -Wno-reorder-ctor -Wno-delete-non-virtual-dtor -Wunused-variable -Wuninitialized -std:c++14

Is there any good way to debug this or is it a known limitation with clang-cl or 32 bit (we don't do 64 yet - but with clang-cl we hope to move towards that soon). Or am I missing some flags?

Thanks, Tobias -------------- next part -------------- A non-text attachment was scrubbed... Name: 108345285-bf402180-71e6-11eb-9090-29f6ebb8423e.png Type: image/png Size: 27244 bytes Desc: not available URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20210309/50384b93/attachment.png>

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