[flang-commits] [PATCH] D114241: [fir] Add !fir.len_param_index conversion

[Diana Picus via Phabricator via flang-commits]

rovka added inline comments.


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Comment at: flang/lib/Optimizer/CodeGen/CodeGen.cpp:852
+    // add the offset into the LENs
+    offset += 0; // FIXME
+    auto attr = rewriter.getI64IntegerAttr(offset);
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I'm not entirely sure what we're supposed to compute here. My understanding is that we have a CFI_cdesc_t with an addendum right after it, and the addendum looks [[ https://github.com/llvm/llvm-project/blob/6623c02d70c3732dbea59c6d79c69501baf9627b/flang/include/flang/Runtime/descriptor.h#L84 | like DescriptorAddendum ]].
So the offset we're trying to compute needs to skip over the whole CFI_cdesc_t and then the derivedType_ member, and potentially other LEN parameters that come first in len_. 
Is this correct? 
Also, what's [[ https://github.com/flang-compiler/f18-llvm-project/blob/1e39e4822cbe2fedbc5dc269ade9f430287a0eda/flang/lib/Optimizer/CodeGen/TypeConverter.h#L213 | this TODO ]] about?


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Comment at: flang/test/Fir/convert-to-llvm-target.fir:162
+  %5 = fir.len_param_index l2, !fir.type<twolens>
+  %6 = fir.len_param_index l, !fir.type<twolens>
+
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Why does it work to use the names of fields? I would expect it to blow up if we pass something that isn't a len param.


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  https://reviews.llvm.org/D114241/new/

https://reviews.llvm.org/D114241