[clang] [llvm] [MC,llvm-readobj,yaml2obj] Support CREL relocation format (PR #91280)

[Peter Smith via llvm-commits]

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@@ -86,6 +86,8 @@ DYNAMIC_TAG(RELRSZ, 35)  // Size of Relr relocation table.
 DYNAMIC_TAG(RELR, 36)    // Address of relocation table (Relr entries).
 DYNAMIC_TAG(RELRENT, 37) // Size of a Relr relocation entry.
 
+DYNAMIC_TAG(CREL,  38)   // CREL relocation table
+
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smithp35 wrote:

While we are using a section type in the [LOOS, HIOS) range, is it worth using a dynamic tag in the [LOOS, HIOS) range.

As an aside, would a tag containing the number of CRELs (NCREL for example). This in theory could be used to pre-allocate memory for an expanded CRELs. I don't think it is worth doing unless there is a clear need though. I could imagine most dynamic linkers iterating through the LEB directly.

Although not strictly necessary a CREL Size (CRELSZ?) could be useful for a consumer to read all the CRELs into memory without having to read the header first to find the size. Again not worth doing unless we have a definite need for it.

https://github.com/llvm/llvm-project/pull/91280