[clang] [compiler-rt] [llvm] [AIX] Implement the ifunc attribute. (PR #153049)

[Timm Baeder via cfe-commits]

tbaederr wrote:

FYI this test fails for us on ppc64le as well:

```
******************** TEST 'LLVM :: CodeGen/PowerPC/aix-ifunc-toc-restore-query-neg.ll' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 5
/builddir/build/BUILD/llvm-project-07ebb18e07fb9e009b1f738d6214a49c7bbe8fee/llvm/redhat-linux-build/bin/llc < /builddir/build/BUILD/llvm-project-07ebb18e07fb9e009b1f738d6214a49c7bbe8fee/llvm/test/CodeGen/PowerPC/aix-ifunc-toc-restore-query-neg.ll -mtriple=powerpc64-ibm-aix-xcoff -test-ifunc-warn-noerror -filetype=obj -o /dev/null 2>&1 | /builddir/build/BUILD/llvm-project-07ebb18e07fb9e009b1f738d6214a49c7bbe8fee/llvm/redhat-linux-build/bin/FileCheck /builddir/build/BUILD/llvm-project-07ebb18e07fb9e009b1f738d6214a49c7bbe8fee/llvm/test/CodeGen/PowerPC/aix-ifunc-toc-restore-query-neg.ll
# executed command: /builddir/build/BUILD/llvm-project-07ebb18e07fb9e009b1f738d6214a49c7bbe8fee/llvm/redhat-linux-build/bin/llc -mtriple=powerpc64-ibm-aix-xcoff -test-ifunc-warn-noerror -filetype=obj -o /dev/null
# note: command had no output on stdout or stderr
# executed command: /builddir/build/BUILD/llvm-project-07ebb18e07fb9e009b1f738d6214a49c7bbe8fee/llvm/redhat-linux-build/bin/FileCheck /builddir/build/BUILD/llvm-project-07ebb18e07fb9e009b1f738d6214a49c7bbe8fee/llvm/test/CodeGen/PowerPC/aix-ifunc-toc-restore-query-neg.ll
# .---command stderr------------
# | /builddir/build/BUILD/llvm-project-07ebb18e07fb9e009b1f738d6214a49c7bbe8fee/llvm/test/CodeGen/PowerPC/aix-ifunc-toc-restore-query-neg.ll:7:10: error: CHECK: expected string not found in input
# | ; CHECK: TOC register save/restore needed for ifunc "foo_ext_decl_ifunc"
# |          ^
# | <stdin>:1:1: note: scanning from here
# | 5880412920", because couldn't prove all candidates are static or hidden/protected visibility definitions
# | ^
# | <stdin>:1:27: note: possible intended match here
# | 5880412920", because couldn't prove all candidates are static or hidden/protected visibility definitions
# |                           ^
# | 
# | Input file: <stdin>
# | Check file: /builddir/build/BUILD/llvm-project-07ebb18e07fb9e009b1f738d6214a49c7bbe8fee/llvm/test/CodeGen/PowerPC/aix-ifunc-toc-restore-query-neg.ll
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |            1: 5880412920", because couldn't prove all candidates are static or hidden/protected visibility definitions 
# | check:7'0     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
# | check:7'1                               ?                                                                               possible intended match
# |            2: 5880413256", because couldn't prove all candidates are static or hidden/protected visibility definitions 
# | check:7'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |            3: 5880413640", because couldn't prove all candidates are static or hidden/
```

see https://github.com/fedora-llvm-team/llvm-snapshots/issues/1911

https://github.com/llvm/llvm-project/pull/153049