[lld] [lld] handle re-exports for full framework paths (PR #137989)

[via llvm-commits]

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@@ -1566,6 +1566,25 @@ static DylibFile *loadDylib(StringRef path, DylibFile *umbrella) {
   return loadDylib(*mbref, umbrella);
 }
 
+static StringRef findFramework(StringRef path, StringRef frameworkName) {
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alx32 wrote:

`findFramework` implies a filesystem-type operation. 

Am I understanding this correctly ? 
```
// Given an install path (e.g., /Path/To/Foo.framework/Versions/A/Foo or
// /Path/To/Bar.framework/Bar) and a framework name (e.g., Foo.framework),
// searches the path components from right-to-left. Returns the substring
// of the install path starting from the first component that matches the
// framework name.
// For example:
//   path = "/Path/To/Foo.framework/Versions/A/Foo", frameworkName = "Foo.framework"
//   -> returns "Foo.framework/Versions/A/Foo"
//   path = "/Path/To/Bar.framework/Bar", frameworkName = "Bar.framework"
//   -> returns "Bar.framework/Bar"
// Returns an empty StringRef if the framework name is not found as a path
// component.
static StringRef getRelativeFrameworkPath(StringRef path,
                                          StringRef frameworkName) {
  size_t end = path.size();
  // Search backwards for the framework name component.
  while (true) {
    // Find the last '/' before the current end position.
    size_t slashPos = path.rfind('/', end);
    if (slashPos == StringRef::npos)
      return StringRef();

    // Extract the component after the slash.
    StringRef component = path.substr(slashPos + 1, end - (slashPos + 1));
    if (component == frameworkName)
      // Found the component, return the relative path starting from here.
      return path.substr(slashPos + 1);

    // Continue searching before the previously found slash.
    end = slashPos;
  }
}
```

https://github.com/llvm/llvm-project/pull/137989