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AMDGPU: Write LDS objects out as global symbols in code generation

Description

AMDGPU: Write LDS objects out as global symbols in code generation

Summary:
The symbols use the processor-specific SHN_AMDGPU_LDS section index
introduced with a previous change. The linker is then expected to resolve
relocations, which are also emitted.

Initially disabled for HSA and PAL environments until they have caught up
in terms of linker and runtime loader.

Some notes:

  • The llvm.amdgcn.groupstaticsize intrinsics can no longer be lowered to a constant at compile times, which means some tests can no longer be applied.

    The current "solution" is a terrible hack, but the intrinsic isn't used by Mesa, so we can keep it for now.
  • We no longer know the full LDS size per kernel at compile time, which means that we can no longer generate a relevant error message at compile time. It would be possible to add a check for the size of individual variables, but ultimately the linker will have to perform the final check.

Change-Id: If66dbf33fccfbf3609aefefa2558ac0850d42275

Reviewers: arsenm, rampitec, t-tye, b-sumner, jsjodin

Subscribers: qcolombet, kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61494

Details

Committed
nhaJun 25 2019, 4:52 AM
Differential Revision
D61494: AMDGPU: Write LDS objects out as global symbols in code generation
Parents
rL364296: AMDGPU/MC: Add .amdgpu_lds directive
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