[clang][lex] Always pass suggested module to `InclusionDirective()` callback (#81061)

This patch provides more information to the
`PPCallbacks::InclusionDirective()` hook. We now always pass the
suggested module, regardless of whether it was actually imported or not.
The extra `bool ModuleImported` parameter then denotes whether the
header `#include` will be automatically translated into import the the
module.

The main change is in `clang/lib/Lex/PPDirectives.cpp`, where we take
care to not modify `SuggestedModule` after it's been populated by
`LookupHeaderIncludeOrImport()`. We now exclusively use the `SM`
(`ModuleToImport`) variable instead, which has been equivalent to
`SuggestedModule` until now. This allows us to use the original
non-modified `SuggestedModule` for the callback itself.

(This patch turns out to be necessary for
https://github.com/apple/llvm-project/pull/8011).

1 files changed, 2 insertions, 1 deletions

diff --git a/clang/lib/Frontend/ModuleDependencyCollector.cpp b/clang/lib/Frontend/ModuleDependencyCollector.cpp
index 939e611..b88cb60 100644
--- a/clang/lib/Frontend/ModuleDependencyCollector.cpp
+++ b/clang/lib/Frontend/ModuleDependencyCollector.cpp
@@ -55,7 +55,8 @@ struct ModuleDependencyPPCallbacks : public PPCallbacks {
                           StringRef FileName, bool IsAngled,
                           CharSourceRange FilenameRange,
                           OptionalFileEntryRef File, StringRef SearchPath,
-                          StringRef RelativePath, const Module *Imported,
+                          StringRef RelativePath, const Module *SuggestedModule,
+                          bool ModuleImported,
                           SrcMgr::CharacteristicKind FileType) override {
     if (!File)
       return;