<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/86548>86548</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [tapi] XCode14 *.tbd + lld (TextAPI) => invalid imports
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            lld
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          alx32
      </td>
    </tr>
</table>

<pre>
    Hello,

I am seeing an issue where using an older version of `tapi` binary to generate `*.tbd`'s for libraries is ending up with invalid binaries after [this change](https://reviews.llvm.org/D149860#inline-1455260). The issue seems to be coming from [SymbolSet.h](https://github.com/llvm/llvm-project/blob/main/llvm/include/llvm/TextAPI/SymbolSet.h#L105) - where if a binary has a `_OBJC_EHTYPE_` for a class, then it is assumed that the binary also has the class. This is not always true - as the following example shows. 

The issue only repro's if using XCode 14's `tapi` binary to generated the `*.tbd` for a library. This is because it exports the `_OBJC_EHTYPE_` as:
```
objc-eh-types:   [ Banana ]
```
Whereas XCode 15 (as well as `llvm-readtapi -stubify`) exports the  `_OBJC_EHTYPE_` as:
```
weak-symbols:    [ '_OBJC_EHTYPE_$_Banana' ]
```

In the below repro, the issue is that `BananaStore_LinkTbd.dylib` is trying to import `_OBJC_CLASS_$_Banana` from `BananaPealer.dylib`.  The class is actually located in `BananaLib.dylib`.

The script requires llvm's `clang`(and `ld64.lld`) and XCode14's `tapi` (or just use the linked `gist`'s).
In the script output, notice the difference when importing the library directly vs the `*.tbd`:
```
Printing where from BananaStore_LinkDirect.dylib imports _OBJC_CLASS_$_Banana:
        __DATA       __objc_data      0x000080C0 bind  BananaLib.dylib/_OBJC_CLASS_$_Banana
Printing where from BananaStore_LinkTbd.dylib    imports _OBJC_CLASS_$_Banana:
        __DATA __objc_data      0x000080C0              bind BananaPealer.dylib/_OBJC_CLASS_$_Banana
```


`repro.sh` (Has to be run on MacOS - update first 2 lines with your paths)
```
CLANG_BIN=~/llvm-project/build/Debug/bin/clang
TAPI_BIN=/Applications/Xcode_14/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/tapi

mkdir -p /tmp/banana_test
cd /tmp/banana_test
rm -f /tmp/banana_test/*

echo '
  __attribute__((objc_root_class)) @interface Banana @end
' > Banana.h

echo '
  #import "Banana.h"
  @implementation Banana @end
  void *_objc_empty_vtable;
  void *_objc_empty_cache;
' > BananaLib.mm

echo '
  #import "Banana.h"
  extern "C" void pealBanana();
  extern "C" void pealBanana() {
    try {} catch (Banana *error) {}
  }
  void *objc_ehtype_vtable;
  void *objc_empty_cache;
  void *objc_empty_vtable;
' > BananaPealer.mm

echo '
  #import "Banana.h"
  @interface BananaStore : Banana @end
  @implementation BananaStore @end
' > BananaStore.mm


DYLD_INFO_BIN=$(xcrun --find dyld_info)
CLANG_COMMON="-nostdlib -fPIC -target arm64-apple-macos -arch arm64 -fuse-ld=lld -Wl,-dylib,-dynamic,-platform_version,macos,11.0.0,11.0.0 -mmacosx-version-min=11.0"

$CLANG_BIN $CLANG_COMMON -o BananaLib.dylib BananaLib.mm
$TAPI_BIN -stubify --filetype=tbd-v4 BananaLib.dylib # BananaLib.tbd - https://gist.github.com/alx32/03bbe94c2e9459bad63825e974195d48
$CLANG_BIN $CLANG_COMMON -o BananaPealer.dylib BananaPealer.mm -Wl,BananaLib.dylib
$TAPI_BIN -stubify --filetype=tbd-v4 BananaPealer.dylib # BananaPealer.tbd - https://gist.github.com/alx32/b800a8547e4686616cc986183051bbec
$CLANG_BIN $CLANG_COMMON -o BananaStore_LinkDirect.dylib BananaStore.mm -Wl,BananaPealer.dylib,BananaLib.dylib
$CLANG_BIN $CLANG_COMMON -o BananaStore_LinkTbd.dylib BananaStore.mm -Wl,BananaPealer.tbd,BananaLib.tbd

echo 'Printing where from BananaStore_LinkDirect.dylib imports _OBJC_CLASS_$_Banana:'
dyld_info -fixups BananaStore_LinkDirect.dylib | grep '_OBJC_CLASS_$_Banana'

echo 'Printing where from BananaStore_LinkTbd.dylib    imports _OBJC_CLASS_$_Banana:'
dyld_info -fixups BananaStore_LinkTbd.dylib | grep '_OBJC_CLASS_$_Banana'
```

Q: Is this actually an issue in llvm or is XCode14's `tapi` producing invalid `*.tbd`'s ? 
Q: Is it possible to hit this issue in any other scenario - or this is strictly related to XCode14 invalid `*.tbd`'s?
</pre>
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