tra added inline comments.

================
Comment at: clang/lib/Driver/ToolChains/Cuda.cpp:161
+      if (FS.exists(LibDevicePath + "/libdevice.10.bc")) {
+        Version = CudaVersion::LATEST;
+        DetectedVersionIsNotSupported = Version > 
CudaVersion::LATEST_SUPPORTED;
----------------
emankov wrote:
> tra wrote:
> > emankov wrote:
> > > Do we have any other mechanism besides version.txt for determining an 
> > > exact CUDA version? Setting the latest version in case of absence of 
> > > version.txt doesn't suit all the needs: sometimes the exact version is 
> > > taken into account, for instance in [[ 
> > > https://github.com/ROCm-Developer-Tools/HIPIFY#clang | hipify-clang ]].
> > Not easily. 
> > 
> > We could try running one of SDK binaries with `--version`. This would be 
> > fragile as the tool version does not necessarily match the SDK's  and 
> > NVIDIA has already started versioning elements per-component. E.g. some 
> > shared libraries in 11.1 are already versioned as 10.2, 11.0, 11.1 and 
> > 11.2. There are also situations when we had to cherry-pick a tool from a 
> > different release in order to work around a critical bug. We don't want to 
> > change compiler's idea of CUDA version based on that.
> > 
> > We could parse CUDA headers and try finding CUDA_VERSION macro. That's 
> > feasible. It may be somewhat fragile if we just search for a text string 
> > '#define CUDA_VERSION XXXX' -- nvidia may change it. On the other hand it's 
> > not that much worse than relying on version.txt.  It also does not carry 
> > complete version, only major.minor, so we will not be able to tell `11.0 
> > `apart from `11.0 update 1`. Probably not a big deal. I don't think we've 
> > needed it so far.
> > 
> > We could do something like this:
> > * if version.txt is there -- use it
> > * otherwise if cuda.h is found, extract version from CUDA_VERSION macro
> > * if that failed, use libdevice bitcode format to detect CUDA-7.0
> > * fall back to "last supported version" otherwise
> > 
> I'd appreciate the appearance of the step with a version extraction from 
> CUDA_VERSION macro.
D89832 does exactly that. PTAL.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D89752/new/

https://reviews.llvm.org/D89752

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