[clang] [llvm] Add ifunc support for Windows on AArch64. (PR #111962)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-sie-ubuntu-fast` running on `sie-linux-worker` while building `clang,llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/144/builds/11605

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang :: CodeGen/ifunc-win.c' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 1: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/clang -cc1 -internal-isystem /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/lib/clang/20/include -nostdsysteminc -triple aarch64-pc-windows-msvc -emit-llvm -o - /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGen/ifunc-win.c | /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGen/ifunc-win.c
+ /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/clang -cc1 -internal-isystem /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/lib/clang/20/include -nostdsysteminc -triple aarch64-pc-windows-msvc -emit-llvm -o - /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGen/ifunc-win.c
+ /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGen/ifunc-win.c
/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGen/ifunc-win.c:46:11: error: CHECK: expected string not found in input
// CHECK: {{.*}} = internal{{.*}}global{{.*}}poison, align 8
          ^
<stdin>:6:42: note: scanning from here
 at global = dso_local global i32 0, align 4
                                         ^
<stdin>:13:1: note: possible intended match here
define dso_local i32 @bar() #0 {
^
/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGen/ifunc-win.c:58:11: error: CHECK: expected string not found in input
// CHECK: define internal void @{{.*}}()
          ^
<stdin>:20:30: note: scanning from here
define dso_local void @bar2() #0 {
                             ^
<stdin>:39:1: note: possible intended match here
define internal ptr @foo_ifunc() #1 {
^

Input file: <stdin>
Check file: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGen/ifunc-win.c

-dump-input=help explains the following input dump.

Input was:
<<<<<<
            1: ; ModuleID = '/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGen/ifunc-win.c' 
            2: source_filename = "/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGen/ifunc-win.c" 
            3: target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-p:64:64-i32:32-i64:64-i128:128-n32:64-S128-Fn32" 
            4: target triple = "aarch64-pc-windows-msvc" 
            5:  
            6:  at global = dso_local global i32 0, align 4 
check:45       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:46'0                                              X error: no match found
            7:  
check:46'0     ~
            8:  at foo = dso_local ifunc i32 (i32), ptr @foo_ifunc 
check:46'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            9:  at goo = dso_local ifunc void (), ptr @goo_ifunc 
check:46'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           10:  at hoo = dso_local ifunc void (i32), ptr @hoo_ifunc 
check:46'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...

```

</details>

https://github.com/llvm/llvm-project/pull/111962