[clang] [clang][modules] HeaderSearch::MarkFileModuleHeader creates extra HeaderFileInfo, breaks PCM reuse (PR #89005)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Ian Anderson (ian-twilightcoder)

<details>
<summary>Changes</summary>

HeaderSearch::MarkFileModuleHeader is no longer properly checking for no-changes, and so creates a new HeaderFileInfo for every `textual header`, causes PCM use to go ballistic.

---
Full diff: https://github.com/llvm/llvm-project/pull/89005.diff


1 Files Affected:

- (modified) clang/lib/Lex/HeaderSearch.cpp (+9-1) 


``````````diff
diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 0632882b296146..9409b97ba0e64a 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -1313,6 +1313,14 @@ OptionalFileEntryRef HeaderSearch::LookupSubframeworkHeader(
 // File Info Management.
 //===----------------------------------------------------------------------===//
 
+static bool
+headerFileInfoModuleBitsMatchRole(const HeaderFileInfo *HFI,
+                                  ModuleMap::ModuleHeaderRole Role) {
+  return (HFI->isModuleHeader == ModuleMap::isModular(Role)) &&
+         (HFI->isTextualModuleHeader ==
+          ((Role & ModuleMap::TextualHeader) != 0));
+}
+
 static void mergeHeaderFileInfoModuleBits(HeaderFileInfo &HFI,
                                           bool isModuleHeader,
                                           bool isTextualModuleHeader) {
@@ -1432,7 +1440,7 @@ void HeaderSearch::MarkFileModuleHeader(FileEntryRef FE,
     if ((Role & ModuleMap::ExcludedHeader))
       return;
     auto *HFI = getExistingFileInfo(FE);
-    if (HFI && HFI->isModuleHeader)
+    if (HFI && headerFileInfoModuleBitsMatchRole(HFI, Role))
       return;
   }
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/89005