[PATCH] D59943: [BPF] add proper multi-dimensional array support

[Yonghong Song via Phabricator via llvm-commits]

yonghong-song created this revision.
yonghong-song added a reviewer: ast.
Herald added subscribers: llvm-commits, jdoerfert.
Herald added a project: LLVM.

  For multi-dimensional array like below
    int a[2][3];
  the previous implementation generates BTF_KIND_ARRAY type
  like below:
    . element_type: int
    . index_type: unsigned int
    . number of elements: 6
  
  This is not the best way to represent arrays, esp.,
  when converting BTF back to headers and users will see
    int a[6];
  instead.
  
  This patch generates proper support for multi-dimensional arrays.
  For "int a[2][3]", the two BTF_KIND_ARRAY types will be
  generated:
    Type #n:
      . element_type: int
      . index_type: unsigned int
      . number of elements: 3
    Type #(n+1):
      . element_type: #n
      . index_type: unsigned int
      . number of elements: 2
  
  The linux kernel already supports such a multi-dimensional
  array representation properly.


Repository:
  rL LLVM

https://reviews.llvm.org/D59943

Files:
  lib/Target/BPF/BTFDebug.cpp
  lib/Target/BPF/BTFDebug.h
  test/CodeGen/BPF/BTF/array-1d-char.ll
  test/CodeGen/BPF/BTF/array-1d-int.ll
  test/CodeGen/BPF/BTF/array-2d-int.ll
  test/CodeGen/BPF/BTF/array-size-0.ll
  test/CodeGen/BPF/BTF/array-typedef.ll
  test/CodeGen/BPF/BTF/static-var-zerolen-array.ll
  test/CodeGen/BPF/BTF/union-array-typedef.ll

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