[PATCH] D87062: [DebugInfo] Add size to class declarations in debug info.

[David Blaikie via Phabricator via cfe-commits]

dblaikie added inline comments.


================
Comment at: clang/lib/CodeGen/CGDebugInfo.cpp:1035
+  const RecordDecl *D = RD->getDefinition();
+  if (D && D->isCompleteDefinition())
+    Size = CGM.getContext().getTypeSize(Ty);
----------------
When is a definition not a complete definition? (sounds like a line from Alice in Wonderland... but I'm genuinely curious/not sure I understand)


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Comment at: llvm/lib/Transforms/Scalar/SROA.cpp:4537-4538
         auto VarSize = DbgDeclare->getVariable()->getSizeInBits();
-        if (VarSize) {
-          if (Size > *VarSize)
-            Size = *VarSize;
-          if (Size == 0 || Start + Size > *VarSize)
-            continue;
-        }
+        assert(VarSize &&
+               "Any variable with a location must have a type with a size");
+        if (Size > *VarSize)
----------------
This is probably a sligthly larger/separate project/patch - @aprantl would it be reasonable to add this as an LLVM IR debug info metadata invariant/tested in the debug info verifier?

(in terms of patch order, I guess:
1) ignoring the size, if present, on declarations in the backend
2) adding the size in the frontend
3) adding an invariant/verifier check that the size is always specified on types of variables with locations - and changing this code here to assert rather than test

But happy to review at least 1 and 2 in this review, though they could/should still be committed separately - the third's probably involved enough to merit a separate review, I'd hazard a guess)


================
Comment at: llvm/test/DebugInfo/X86/struct-fwd-decl.ll:19
+; CHECK-NOT: DW_AT_byte_size
+; CHECK-NEXT: DW_AT_declaration
+!6 = !{!0}
----------------
Probably CHECK-NOT DW_AT_byte_size again, and CHECK: DW_TAG so that even if the fields are reordered a byte_size can't slip in anywhere.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D87062/new/

https://reviews.llvm.org/D87062