<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/68915>68915</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [RISCV] Relax linker requireement of exact match between floating point ABIs
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            lld,
            backend:RISC-V
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          hiraditya
      </td>
    </tr>
</table>

<pre>
    Linking object files of a floating point and a double floating point ABI causes linker error.
e.g.,

```
$ llvm-readelf -h icudtl.o
ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
 Class:                             ELF64
  Data: 2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              REL (Relocatable file)
  Machine:                           RISC-V
 Version:                           0x1
  Entry point address: 0x0
  Start of program headers:          0 (bytes into file)
  Start of section headers:          817488 (bytes into file)
  Flags: 0x0
  Size of this header:               64 (bytes)
 Size of program headers:           0 (bytes)
  Number of program headers: 0
  Size of section headers:           64 (bytes)
  Number of section headers:         4
  Section header string table index: 1

Note that the "Flags" bits are 0x0.
```

```
$ llvm-readelf -h fml.file.o
ELF Header:
  Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF64
 Data:                              2's complement, little endian
 Version:                           1 (current)
  OS/ABI: UNIX - System V
  ABI Version:                       0
  Type: REL (Relocatable file)
  Machine: RISC-V
  Version:                           0x1
  Entry point address:               0x0
  Start of program headers:          0 (bytes into file)
  Start of section headers:          695248 (bytes into file)
  Flags:                             0x5, RVC, double-float ABI
 Size of this header:               64 (bytes)
  Size of program headers: 0 (bytes)
  Number of program headers:         0
  Size of section headers:           64 (bytes)
  Number of section headers: 5

Note that "Flags" is 0x5 (double-float ABI)
```

ld.lld: error: icudtl.o: cannot link object files with different floating-point ABI from fml.file.o


Linking  same object files for ARM target doesn't give an error where they have differing flags as well.

e.g., 

```
readelf -h icudtl.o
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 61 00 00 00 00 00 00 00 00
  Class: ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI: ARM
  ABI Version:                       0
  Type: REL (Relocatable file)
  Machine: ARM
  Version:                           0x1
  Entry point address:               0x0
  Start of program headers:          0 (bytes into file)
  Start of section headers:          817472 (bytes into file)
  Flags:                             0x0
  Size of this header: 52 (bytes)
  Size of program headers:           0 (bytes)
 Number of program headers:         0
  Size of section headers: 40 (bytes)
  Number of section headers:         5
  Section header string table index: 2

Generated by the compiler:


$ readelf -h fml.file.o
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data: 2's complement, little endian
  Version: 1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type: REL (Relocatable file)
  Machine: ARM
  Version:                           0x1
  Entry point address: 0x0
  Start of program headers:          0 (bytes into file)
 Start of section headers:          423636 (bytes into file)
  Flags: 0x5000000, Version5 EABI
  Size of this header: 52 (bytes)
  Size of program headers:           0 (bytes)
 Number of program headers:         0
  Size of section headers: 40 (bytes)
  Number of section headers:         1120
  Section header string table index: 1
```

</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzkmF1v6jYYxz-NuXlElDgvwAUXHApbpfZMolu1Wyd5Qrzj2Mw2LezTTw6EQqEBjjjdtEVRWpQ8r7Z_-TvMGD6XiEMSfyHxXYctban0sOSa5dyuWSdV-Xr4wOU3Lueg0j8ws1BwgQZUAQwKoZh1txaKSwtM5sAgV8tU4Pt7oy_3kLGlQQOCy2-oAbVW2iP-HfFH6M09QsebH9tr4m_PzU8agRAvVVcjy1EU0C2BZ8vcCk9tnpg8TOFnd1OTcOsD4JHNeUbCEQD0CohiiDKIEvAp-EF9-h-dWw9jwYzZOPj4mDxMk6gJeccscwaU0J6BTFULgRVKS-gYBLdWIKDMOZONwTNqw5VsDxIAof1sqXXtadDY_vJE6HT05f5Mhr99vf8duvC0NhYreG6s3aCcjd50An5dL_BcJ2A2eXCZzlCojFlWzwQucC_lR5aVXJ7xNLt_GnebPC9qkL8KmggTafW6mZN5rnEzgv5qV8qTZdq6ObzQaq5ZBWU9cQ4H2neFpGuLBri06n0dOx8GM8uVPOmjH_Sifr_d0VSw-VGC_C90vm3JzdbxcflJtHP85q6xbKtsr7S9PL4uqxT1B7ZHmbVVfTqzvQAtxrt19HTwDBirHU02U4rLHFfOKthHxldlEWzJLNgSgVC66SylkHJrgGl0LfZO8-VS6BSV8NwA_ljsXM-dBjutx6VMuhWSbsqdq9ByAJBbEeT985_Pk2QQ0-hSnrQd_ip2gz97Hrs_m3d2t35nu9F5x5LrKdSGoevhczQlfhSE4tM42UcJN653zvNR05ogJ9Eick-I3AWphY_7Z6dfwhFkTEpla210KLReuS0h50WBbp3tZFX3TVYVWlVHWNq_NgIODKvw0HuhNIxmj2CZnqOFXKGRhPYszPkLApObZOG1RO16gWso2Qtu83E-C9cXYAZeUQhvP-pW00ELX2-j5YLtmXzI1SOoTh6mIX0v2FqPT1dzo9njJ-JyL9p_hpVOe_XoTVh5TpfF9EoGnqr0zfJmMIzOsLalffFVOozur_KfUKJmFnNI17UUc8uGi73FfHClEdxKXwU311fHmPgeEvyLdm__MBZuC4KLOBDRMAmTi_dgsV8fbli3NccwedNE_yMEBAH1v2s3dviW7-TDMB-EA9bBYZAMekEY0DDulMM07AVJWCSDrJew2O9jv0gxjopk4Md5zAYdPqQ-DQM_oEGP-mHsBTSOWRyFAwz8Xi8NSORjxbjw3C7NU3re4cYscZj0B0HcESxFYeqPW5Q68UUpoWNCacqybyidGNtuEygl8V1HD-vNXrqcGxL5ghtr3hxbbkX9ocyZPJP4DmYo2Kr5mqXxzyXXWBPBtRVXLLNQMZuVkKJ9RZQnPomZzlKLYWntwjWe0Cmh0zm35TL1MlUROnXht3-6C62cciN0WhdpCJ3Wdf4dAAD__-yJaW8">