[all-commits] [llvm/llvm-project] 8d7a8f: [SHT_LLVM_BB_ADDR_MAP] Encode and decode callsite ...

[Rahman Lavaee via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 8d7a8fcc3ab9f6d4c4a7e4312876fe94ed3d6c4f
      https://github.com/llvm/llvm-project/commit/8d7a8fcc3ab9f6d4c4a7e4312876fe94ed3d6c4f
  Author: Rahman Lavaee <rahmanl at google.com>
  Date:   2025-06-23 (Mon, 23 Jun 2025)

  Changed paths:
    M llvm/include/llvm/Object/ELFTypes.h
    M llvm/include/llvm/ObjectYAML/ELFYAML.h
    M llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
    M llvm/lib/Object/ELF.cpp
    M llvm/lib/ObjectYAML/ELFEmitter.cpp
    M llvm/lib/ObjectYAML/ELFYAML.cpp
    M llvm/test/tools/llvm-readobj/ELF/bb-addr-map.test
    M llvm/test/tools/obj2yaml/ELF/bb-addr-map.yaml
    M llvm/test/tools/yaml2obj/ELF/bb-addr-map.yaml
    M llvm/tools/llvm-readobj/ELFDumper.cpp
    M llvm/tools/obj2yaml/elf2yaml.cpp
    M llvm/unittests/Object/ELFObjectFileTest.cpp
    M llvm/unittests/Object/ELFTypesTest.cpp

  Log Message:
  -----------
  [SHT_LLVM_BB_ADDR_MAP] Encode and decode callsite offsets in a newly-introduced SHT_LLVM_BB_ADDR_MAP version. (#144426)

Recently, we have been looking at some optimizations targeting
individual calls. In particular, we plan to extend the address mapping
technique to map to individual callsites. For example, in this piece of
code for a basic blocks:

```
<BB>:
1200:    lea 0x1(%rcx), %rdx
1204:    callq foo
1209:    cmpq 0x10, %rdx
120d:    ja  L1
```

We want to emit 0x9 as the call site offset for `callq foo` (the offset
from the block entry to right after the call), so that we know if a
sampled address is before the call or after.

This PR implements the decode/encode/emit capability. The Codegen change
will be implemented in a later PR.



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