[clang][CodeGen] Switch declaration of vtable information to be [0 x ptr] #65596
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…ptr] Before we had this code: @_ZTVN10__cxxabiv117__class_type_infoE = external global ptr now we'll produce: @_ZTVN10__cxxabiv117__class_type_infoE = external global [0 x ptr] This is because we may not know the exact size of this data, and clang issues gep inbounds with idx=2. Before, that gep would always result in poison.
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| @@ -14,8 +14,8 @@ class B : A { | |||
| // NO-AS: @_ZTISt9type_info = external constant ptr | |||
| // AS: @_ZTIi = external addrspace(1) constant ptr addrspace(1) | |||
| // NO-AS: @_ZTIi = external constant ptr | |||
| // AS: @_ZTVN10__cxxabiv117__class_type_infoE = external addrspace(1) global ptr addrspace(1) | |||
| // NO-AS: @_ZTVN10__cxxabiv117__class_type_infoE = external global ptr | |||
| // AS: @_ZTVN10__cxxabiv117__class_type_infoE = external addrspace(1) global [0 x ptr] | |||
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Maybe this should be [0 x ptr addrspace(1)]? Not sure that makes any semantic difference, but it would be more clear. (So use llvm::ArrayType::get(CGM.GlobalsInt8PtrTy, 0).)
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LGTM |
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Continuing the discussion in https://discourse.llvm.org/t/codegen-layout-of-si-class-type-info-doesnt-match-the-actual-size/73274
Before we had this code:
@_ZTVN10__cxxabiv117__class_type_infoE = external global ptr
now we'll produce:
@_ZTVN10__cxxabiv117__class_type_infoE = external global [0 x ptr]
This is because we may not know the exact size of this data, and clang issues gep inbounds with idx=2. Before, that gep would always result in poison.