[PATCH] D12618: Reserve a vendor reserved block ID for bitcode

[Rafael Espíndola via llvm-commits]

Needs a test showing that it is actually ignored.

Can you expand on how you intend this to be used? We have a documented
policy on supporting old bitcode:

http://llvm.org/docs/DeveloperPolicy.html#ir-backwards-compatibility


Is that not what you are looking for?


On 3 September 2015 at 20:11, Mehdi AMINI <mehdi.amini at apple.com> wrote:
> joker.eph created this revision.
> joker.eph added a reviewer: rafael.
> joker.eph added a subscriber: llvm-commits.
>
> The idea is that vendor toolchains can insert a block for their own
> internal purpose while generating bitcode that will be compatible
> with the open-source tools. The latter just ignoring this block.
>
> We (Apple) intend to use it for versioning the bitcode. The versioning
> would not make sense with respect to open-source release since our
> internal versions/releases don't align.
>
> http://reviews.llvm.org/D12618
>
> Files:
>   include/llvm/Bitcode/LLVMBitCodes.h
>
> Index: include/llvm/Bitcode/LLVMBitCodes.h
> ===================================================================
> --- include/llvm/Bitcode/LLVMBitCodes.h
> +++ include/llvm/Bitcode/LLVMBitCodes.h
> @@ -34,7 +34,8 @@
>      CONSTANTS_BLOCK_ID,
>      FUNCTION_BLOCK_ID,
>
> -    UNUSED_ID1,
> +    // Valid inside vendor specific toolchains only, discarded by open-source
> +    VENDOR_RESERVED_ID,
>
>      VALUE_SYMTAB_BLOCK_ID,
>      METADATA_BLOCK_ID,
>
>