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[MLIR] Correct linkage of lowered globalop

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LLVM considers global variables marked as externals to be defined within the module if it is initialized (including to an undef). Other external globals are considered as being defined externally and imported into the current translation unit. Lowering of MLIR Global Ops does not properly propagate undefined initializers, resulting in a global which is expected to be defined within the current TU, not being defined.

Differential Revision: https://reviews.llvm.org/D108252
This commit is contained in:
William S. Moses 2021-08-17 18:22:04 -04:00
parent 7151a8aada
commit 8c2ff7b69e
2 changed files with 13 additions and 2 deletions
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10
mlir/lib/Conversion/MemRefToLLVM/MemRefToLLVM.cpp
View file

@ -454,9 +454,17 @@ struct GlobalMemrefOpLowering
initialValue = elementsAttr.getValue({});
}
rewriter.replaceOpWithNewOp<LLVM::GlobalOp>(
auto newGlobal = rewriter.replaceOpWithNewOp<LLVM::GlobalOp>(
global, arrayTy, global.constant(), linkage, global.sym_name(),
initialValue, /*alignment=*/0, type.getMemorySpaceAsInt());
if (!global.isExternal() && global.isUninitialized()) {
Block *blk = new Block();
newGlobal.getInitializerRegion().push_back(blk);
rewriter.setInsertionPointToStart(blk);
Value undef[] = {
rewriter.create<LLVM::UndefOp>(global.getLoc(), arrayTy)};
rewriter.create<LLVM::ReturnOp>(global.getLoc(), undef);
}
return success();
}
};

5
mlir/test/Conversion/MemRefToLLVM/memref-to-llvm.mlir
View file

@ -623,7 +623,10 @@ func @transpose(%arg0: memref<?x?x?xf32, offset: ?, strides: [?, ?, 1]>) {
// -----
// CHECK: llvm.mlir.global external @gv0() : !llvm.array<2 x f32>
// CHECK: llvm.mlir.global external @gv0() : !llvm.array<2 x f32> {
// CHECK-NEXT: %0 = llvm.mlir.undef : !llvm.array<2 x f32>
// CHECK-NEXT: llvm.return %0 : !llvm.array<2 x f32>
// CHECK-NEXT: }
memref.global @gv0 : memref<2xf32> = uninitialized
// CHECK: llvm.mlir.global private @gv1() : !llvm.array<2 x f32>