[llvm] Add support to YAML for program headers with content. (PR #192364)

[Greg Clayton via llvm-commits]

clayborg wrote:

I am not sure the "Fill" sections help us at all. If I want to create a PT_NOTE program header and put data into, there is no way to specify where the data for the fill goes is there? Here is what I tried:
```
--- !ELF
FileHeader:
  Class: ELFCLASS64
  Data:  ELFDATA2LSB
  Type:  ET_DYN
ProgramHeaders:
  - Type:            PT_NOTE
    Align:           0x4
    MemSize:         0x0
    Offset:          0x120
Sections:
  - Type:    Fill
    Pattern: "112233445566778899AA"
    Size:    10
```

How would I specify that this `Fill` data should go into the  PT_NOTE? And if I create many PT_LOAD segments for the core file memory, how would I force this data to go into those PT_LOAD program headers?


https://github.com/llvm/llvm-project/pull/192364