Michael137 wrote: > It looks like this is working for all other kinds of structured binding > because `EmitDeclare(BindingDecl*, ...)` emits a proper `DILocalVariable` for > them. But it skips `BindingDecl`s that have a holding variable for some > reason. Perhaps a cleaner approach would be to make it handle that case too, > and leave the holding variables themselves as artificial?
Yea that would be ideal. I was thinking of doing this, but wasn't quite sure how to best re-architect the codegen for structured bindings to make this happen. We currently emit debug-info for structured bindings in 2 steps. The [`DecompositionDecl` itself gets codegen'd first](https://github.com/llvm/llvm-project/blob/c6e69b041a7e6d18463f6cf684b10fd46a62c496/clang/lib/CodeGen/CGDecl.cpp#L165). Which is what calls into `CGDebugInfo::EmitDeclare(BindingDecl*, ...)`. This creates a debug-info entry for the unnamed decomposition pair. But then [`CodeGenFunction::EmitDecl` calls `EmitVarDecl` for each holding var](https://github.com/llvm/llvm-project/blob/c6e69b041a7e6d18463f6cf684b10fd46a62c496/clang/lib/CodeGen/CGDecl.cpp#L169). This then goes through various layers of codegen until we hit `CGDebugInfo::EmitDeclare(VarDecl*,...)`. Hence we bail out early in the case of tuple-like bindings in step 1, and defer to `CGDebugInfo::EmitDeclare(VarDecl*)` to emit debug-info for each individual holding var. So at some point in the code-gen process we need to bail out early in the case of structured bindings. AFAICT we have two options: 1. Detect the fact that we're dealing with holding vars [before calling `CGDebugInfo::EmitDeclare(VarDecl*)` ](https://github.com/llvm/llvm-project/blob/c6e69b041a7e6d18463f6cf684b10fd46a62c496/clang/lib/CodeGen/CGDecl.cpp#L1680-L1682). And just emit all the debug-info for a decomposition in `CGDebugInfo::EmitDeclare(BindingDecl*, ...)` 2. OR, detect that we're emitting holding vars in `CGDebugInfo::EmitDeclare(BindingDecl*, ...)`, and emit the debug-info for them in `CGDebugInfo::EmitDeclare(VarDecl*, ...)`. Which is what the current patch is doing. Any preferences here? Or maybe I'm missing a better approach https://github.com/llvm/llvm-project/pull/100355 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
