Structured buffers

[bogner]

• llvm/llvm-project#106189
• llvm/llvm-project#112775
• llvm/llvm-project#112776
• llvm/llvm-project#112777
• llvm/llvm-project#112977
• llvm/llvm-project#113513
• llvm/llvm-project#112968
• llvm/llvm-project#112984
• llvm/llvm-project#106188
• llvm/llvm-project#92147
• llvm/llvm-project#112982
• llvm/llvm-project#114130
• llvm/llvm-project#121714
• llvm/llvm-project#122663