[PATCH] D155125: [amdgpu][lds] Introduce LDS frame size function attribute

[Jon Chesterfield via Phabricator via llvm-commits]

JonChesterfield added a comment.

As a standalone patch, this makes the compiler slightly slower and introduces a fatal error where there previously wasn't one. I'd still like to land it ahead of removing allocateKnownAddressLDSGlobal as it's easier to sanity check the test changes in isolation.



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Comment at: llvm/lib/Target/AMDGPU/AMDGPULowerModuleLDSPass.cpp:1210
 
     {
       const DataLayout &DL = M.getDataLayout();
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Currently this frame layout is passed in as hoc fashion based on kernel structs having a name derived from the corresponding kernel.

However the backend doesn't actually need the exact frame layout because the globals also have absolute_address metadata on them.

Introduce an attribute (name chosen to be similar to amdgpu-gds-size) which records the frame size.


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Comment at: llvm/lib/Target/AMDGPU/AMDGPUMachineFunction.cpp:124
 
   if (isModuleEntryFunction()) {
 
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This frame logic will be deleted in a subsequent patch, leaving only amdgpu-lds-size as the lookup. At that point it can probably move to the function constructor and this allocate known address function can be deleted.

In the first instance, add a fatal error if the different accounting have gone awry. Landing this patch (and watching it go through internal CI) is supporting evidence that the two data representations are equivalent.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D155125/new/

https://reviews.llvm.org/D155125