[AST Print] Attribute `asm` is dumped in the incorrect location

[giulianobelinassi]

With the following input saved as test.c (input code from glibc):

extern const char _libc_intl_domainname[];
extern typeof (_libc_intl_domainname) _libc_intl_domainname asm("__GI__libc_intl_domainname")  __attribute__((visibility("hidden")));

This input is successfully accepted by clang, as it shows no output:

$ clang -S test.c

However, dumping the AST:

$ clang -Xclang -ast-print -S test.c -o test.print.c

dumps an output that is not accepted by clang:

clang -S test.print.c
test.print.c:2:98: error: expected ';' after top level declarator
    2 | extern typeof (_libc_intl_domainname) _libc_intl_domainname __attribute__((visibility("hidden"))) asm("__GI__libc_intl_domainname");
      |                                                                                                  ^
      |                                                                                                  ;
1 error generated.

Output of clang --version:

$ clang --version
clang version 21.1.1
Target: x86_64-suse-linux
Thread model: posix
InstalledDir: /usr/bin

Related PRs: 87281, #88600
Requesting comments from @vgvassilev

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Giuliano Belinassi (giulianobelinassi)

With the following input saved as `test.c` (input code from glibc): ``` extern const char _libc_intl_domainname[]; extern typeof (_libc_intl_domainname) _libc_intl_domainname asm("__GI__libc_intl_domainname") __attribute__((visibility("hidden"))); ``` This input is successfully accepted by clang, as it shows no output: ``` $ clang -S test.c ``` However, dumping the AST: ``` $ clang -Xclang -ast-print -S test.c -o test.print.c ``` dumps an output that is not accepted by clang: ``` clang -S test.print.c test.print.c:2:98: error: expected ';' after top level declarator 2 | extern typeof (_libc_intl_domainname) _libc_intl_domainname __attribute__((visibility("hidden"))) asm("__GI__libc_intl_domainname"); | ^ | ; 1 error generated. ``` Output of clang --version: ``` $ clang --version clang version 21.1.1 Target: x86_64-suse-linux Thread model: posix InstalledDir: /usr/bin ```

Related PRs: 87281, #88600
Requesting comments from @vgvassilev

[AaronBallman]

FWIW, -ast-print is generally best-effort and so while this is an issue, it's not one likely to be organically solved unless someone wants to work on the problem.

I'm pretty sure the issue is with

llvm-project/clang/lib/AST/DeclPrinter.cpp

Line 255 in 6419046

bool DeclPrinter::prettyPrintAttributes(const Decl *D,

because the asm label is handled as an attribute but there's no special logic to ensure it gets printed out in the order expected by the parser.

[vgvassilev]

@giulianobelinassi, that's quite subtle. Do you want to take a stab at fixing this? Should be a relatively straight-forward fix as Aaron mentioned.