<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=http://email.email.llvm.org/c/eJzlV0lv4zYU_jX2hbCh3fLBBydO2gFazGCaYoBeBIqiLDY0KZCUk8yv73uUFzmx4xRTzKWCVvJtfBs_lbp6WTBJ1ZqUnZCOPAnXkHmWlzxIy7yuWFhFMQvSlLFknsVRHNB8zuuSpfNsRkZRHgVRNAnCSRiNovkoWI2C5QM1a-5G8ZI851mRJZNOPSr9pCZSqO55slZdT9ffb712qzfciQ23hG-Es2T1rXhY_lKU1PLCvbScrD7d2d4613BCnTOi7BxHwuVDUb44XljxnRPLHXGaBFPy0AhL4NSl5WZLS8nJU8MV4QreBehcfVt-vd-mRCgvs9ZS6iecMLw1uuoYN1Pym9aPoM5TgA1AZXqdd0WnrFgrXhUhOiJ4DvwRxeAI0CRYg9o7y6u9BqkZdUKDCc-t4dbiK8obZUEJ11BKwlEKtaSlxhFdE0qYVltuPBMQgg2fvxT9mAPa6dCnIGx39p9RQkAzqJ2ytu3HiuLgw6IAeXDq1imtUPEhlFstKmADBXmptUSbRrOb0Wx1UYjSQoF330qpO7WTQsq9HD9L9gqQPt4NHlQI5ciGCuWln3D1Ap3p-JCRQPRcZxQJ3so6uaNPfOpNGJl8jshkXT1RU0_SnZvIROObPpJLud1MPFHVbVriuHX76UHwIe3Jm_Td23Z69Lmr6Abm536B0ZvUgrGDH8_zc8V0BWnby3gl4ArvoW56ZlzGgePVymb_8cryn72y8Liy-NYq0Y7iu9M1JtHJGm1XQh9YG7p5TxH0jKJlR__tjwTOMrhiZSPWzWXu9Ap3DaZxH4qDh6AnGL6eka9_fLnCzKiUBV74YnsB-2J6b7lCPdI1P41t8VcM1Vhej-gJly_gaxwVZ7KohTyyjaL7BnYLeGjWwL3iW7iX3drCwzJDnR_eNbuPKfAdyytIruXks-NGUXnGYa-SiffJdEgn6PQbKgto6OAEEHJeyzGt-r1iGNkSQpuSr6tPo-gGMuuWHDYB6zoSPNe74zhFVXVCh5vF283qYt95j3N2gTM_4bSOssdiS-U7iXU2Od5Npp-QHP86PfYMfVMc1vOcop_6_fOo8PUePbhLWZXE0hfrUcOWGuHRC6IJRbdUSP8JsSUNl23dSfmCmEUbAE6g4k9luxa_AHl47OSBEWCQV5gBu91ZW_7H2OCICi5CgiEggDgdBmZ3F_PtNWmU4zfa7DxWJsxwCmAWYgI0EJgeGXfGcIWwjbPO-Zjv0O0Iq--DiQ60WLc9FB8AxaMNpXeXH70BOx5bjY4NsX0BYDZgVrxC27PgGCePTg-IMl6mcMVY9rSqENp6njPb4WvdZq_5i9EM-bJonhJJO8Ua2OPBhB9Z6xnR1um2Bck7Q5ZQYrDmCtjiEO3HJuSNB1leIA4iE-QOtYi9Ya4cuGkaHvuB35BRVICWv13-iRdBEACRQUUjHjnr1r38CC5oLVcKD4jinvCDJQjEyUDyxWKcgIEk7SnPFiZMZf300JhZP3S5WEm-l3m-bAfp0oJJfowbow06-VZ3sgKuGUqHXVVQiaAPZthxBkusb6WwD-Hf1KGnlkj5wYZ5rlWOq0VczeM5HdPONdosPt_--kI3dtwZuWicay022egezjX8vHbllOkNfOC_xO4xAZD5N2fgzXthbccxqdM4zOJxs6hpHmS04pTN5zyZMzbjMx7mjKbhrOZlOYbE4dIuRukNtI2KQ00IVWtsIelq_OMWiAX-3wdhGIVZEsbZNKuTKK_zKog5LZMqHCUBh6jKKcqZarMem4UX6aszCaSwzh4nqfUogXuDwUInnPQf_l8cRvAVV_EJV5GuyO9gEP6S7wNmSQURhBbYd2nohw6nj1GDqe_c6LFfyMKv4h9kFcbN>53163</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [DWARF][DebugInfo] Missing variables due to clang setting type size to zero
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            debuginfo
      </td>
    </tr>

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

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

<pre>
    clang built with 968be05b8fdc1d23c055cc4963230a89efbc5967 (2022-01-12)
Target: x86_64-unknown-linux-gnu

Clang sometimes emits DW_TAG_base_type DIEs with the attribute DW_AT_byte_size set to 0. This is observable when enabling DWARFv5 in the following reproducer. Look at the DIE for DW_ATE_unsigned_1 (0x00000023) which is used in the location expression for `b` (0x0000004e) as part of a conversion (DW_OP_convert).

```
$ cat ex.cpp
__attribute__((optnone))
void ext(bool) {}
__attribute__((noinline))
void fun(bool b) {
  ext(b);
}
int main() {
  fun(true);
  return 0;
}


$ clang -c -O2 -gdwarf-5 ex.cpp -o ex.o
$ llvm-dwarfdump test.o
0x00000023:   DW_TAG_base_type
                DW_AT_name      ("DW_ATE_unsigned_1")
                DW_AT_encoding  (DW_ATE_unsigned)
                DW_AT_byte_size (0x00)

0x00000027:   DW_TAG_base_type
                DW_AT_name      ("DW_ATE_unsigned_8")
                DW_AT_encoding  (DW_ATE_unsigned)
                DW_AT_byte_size (0x01)
<snip>
0x00000042:   DW_TAG_subprogram
                DW_AT_low_pc    (0x00000000004004b0)
                DW_AT_high_pc   (0x00000000004004b5)
                DW_AT_frame_base        (DW_OP_reg7 RSP)
                DW_AT_call_all_calls    (true)
                DW_AT_linkage_name      ("_Z3funb")
                DW_AT_name      ("fun")
                DW_AT_decl_file ("/home/och/dev/bugs/scratch/ex.cpp")
                DW_AT_decl_line (4)
                DW_AT_external  (true)

0x0000004e:     DW_TAG_formal_parameter
                  DW_AT_location        (DW_OP_breg5 RDI+0, DW_OP_constu 0xffffffff, DW_OP_and, DW_OP_convert (0x00000023) "DW_ATE_unsigned_1", DW_OP_convert (0x00000027) "DW_ATE_unsigned_8", DW_OP_stack_value)
                  DW_AT_name    ("b")
                  DW_AT_decl_file       ("/home/och/dev/bugs/scratch/ex.cpp")
                  DW_AT_decl_line       (4)
                  DW_AT_type    (0x0000009a "bool")
```


lldb says the variable is unavailable and helpfully reports "Unsupported type size in DW_OP_convert":
```
__attribute__((optnone))
void ext(bool) {}
__attribute__((noinline))
void fun(bool b) {
  ext(b);
}
int main() {
  fun(true);
  return 0;
}

$ clang -O2 -gdwarf-5 ex.cpp -o ex
$ lldb ex
~/dev/bugs/scratch$ lldb ex
(lldb) target create "ex"
Current executable set to '/home/och/dev/bugs/scratch/ex' (x86_64).
(lldb) b fun
Breakpoint 1: where = ex`fun(bool) at ex.cpp:5:3, address = 0x00000000004004b0
(lldb) run
Process 6295 launched: '/home/och/dev/bugs/scratch/ex' (x86_64)
Process 6295 stopped
* thread #1, name = 'ex', stop reason = breakpoint 1.1
    frame #0: 0x00000000004004b0 ex`fun(b=<unavailable>) at ex.cpp:5:3
   2    void ext(bool) {}
   3    __attribute__((noinline))
   4    void fun(bool b) {
-> 5           ext(b);
   6    }
   7    int main() {
   8      fun(true);
(lldb) p b
error: Couldn't materialize: couldn't get the value of variable b: Unsupported type size in DW_OP_convert
```

</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzlV0lv4zYU_jXyhbCh3fLBBydO2gFazGCawQC9CJREWWxoUiApJ5lf3_co25ITO07RYi4VtJJv49v4qVDVy7IUVG5I0XFhyRO3DVmkWcH8pMjqqgyqMCr9JCnLeJFGYeTTbMHqokwW6Zx4YRb6YTj1g2kQeuHC89eev3qgesOsF63Ic5bmaTzt5KNUT3IquOyepxvZ9XT9_dZpN2rLLN8yQ9iWW0PW3_OH1S95QQ3L7UvLyPrTnemtsw0j1FrNi84yJFw95MWLZbnhPxgxzBKriD8jDw03BE5VGKZ3tBCMPDVMEibhnYPO9ffV1_tdQrh0MmslhHrCCc1araquZHpGflPqEdQ5CrABqHSv8y7vpOEbyao8QEf4z747wggcAZp42aD2zrDqoEGoklquwITnVjNj8BXlealfwDWWEjOUQg1pqbZE1YSSUskd044JCMGGz1_yfswC7WzsUxC2P_vPMCagGdTOyrbtx_L86MM8B3lwqtZKJVHxMZQ7xStgAwVZoZRAm7z5jTdfXxQiFZfg3bdS6k7upZDiIMfNkoMCpI_2g0cVXFqypVw66SdcvUCrOzZmJBA922lJ_LeyTu7oE5d605JMP4dkuqmeqK6nyd5NZKrwTQ3kQuy2U0dUdduWWGbsYXoUfEh78iZ9D7adHn3uSrqF-YVbYPgmtWDs6Mfz_EyWqoK07WW8EnCF91g3PTMu48jxamXz_3hl2c9eWTCsLLo1krdedHe6xjg8WaPpCugDG0237ymCnpG35eC_wxHDWfhXrGz4prnMnVzhrsE05kJx9BD0BM02c_L1jy9XmEsqRI4XvphewKGY3lsul490w05jm_8ZQTUW1yN6wuUK-BpHxUqR11wMbF5438BuAQ9VNnCv2A7uRbcx8DClptYN75vdxxS4juUUxNdy8tkyLak447BXycT6ZDqmE3T6LRU5NHRwAgg5r2VIq36vGEe2gNAm5Ov6kxfeQGbdkuMmYGxH_Od6fwxTVFYndLhZvN2sLvad9zjnFzizE05jafmY76h4J7HOJse7yfQTkuMfp8eBoW-K43peUPRTv38OCl_v0aO7EFVBDH0xDjXsqOYOvSCakHRHuXCfEFvSMNHWnRAviFmUBuAEKr5J07X4BcjDYScHjACDvMIM2O3O2vI_xgYDKrgICcaAAOJ0HJjfXcy316Rhht9os3VYmZSaUQCzEBOggcD0yLjTmkmEbazsrIv5Ht16WH0fTHSgxbrtofgIKA42FM5dbvQG7HhsFTo2wPYFgFmDWdEabU_9IU4OnR4RZbRK4Iqw7GlVIbR1PGe2w9e69UHzF61K5EvDRUIE7WTZwB4PJvybtZ4RbaxqW5C8N2QFJQZrroAtCtB-bELOeJDlBOIgMkHuUIPYG-aKkZtmwdAP3IaMony0_O3yT7wIggCIjCoa8chZtx7kh3BBa7lSeEAU9YQfLEEgjkeSLxbjFAwkSU95tjBhKu2nx8bM-6HLxUqyg8zzZTtKlxZMcmNMa6XRybeqExVwzVE67KqcCgR9MFMOM1hifSuFfQj_po49tUDKDzbMc61yUi2jahEt6MRyK9jSS27cb6WXrPGVQZJ-krWCT_I7hz8-6CwH3YZUYAxUc99woLQtTg8GwNQPptWk02LZWNsa7NfhPZwb-A_uilmptvCBvyX7xxTw6l-shMDcg7KOYX0kUZBGk2YZpumcJkHsZ0WaVUERxul8vojLeRFFRZ0GE8hBJgyuADpQhZZztBy6UbKe8CX-6PtBEAZpHETpLK3jMKuzyo8YLeIq8GKfQXjFDO2YKb2Z6KUzyZVp7AturBkmqXFwwTkM5dPONkovP9_--kK3ZuKsXzrT_waXTa91">