[clang] [clang][modules] Allow module maps with textual headers to be non-affecting (PR #89441)

[Jan Svoboda via cfe-commits]

https://github.com/jansvoboda11 updated https://github.com/llvm/llvm-project/pull/89441

>From 9165d6086e2570198fba1c333d0c9cb9c09037c7 Mon Sep 17 00:00:00 2001
From: Jan Svoboda <jan_svoboda at apple.com>
Date: Fri, 19 Apr 2024 12:13:06 -0700
Subject: [PATCH 1/2] [clang][modules] Allow module map files with textual
 header be non-affecting

---
 clang/lib/Serialization/ASTWriter.cpp         | 10 ++++---
 ...e-non-affecting-module-map-files-textual.c | 26 +++++++++++++++++++
 2 files changed, 32 insertions(+), 4 deletions(-)
 create mode 100644 clang/test/Modules/prune-non-affecting-module-map-files-textual.c

diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 8a4b36207c4734..4825c245a4b846 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -187,7 +187,8 @@ GetAffectingModuleMaps(const Preprocessor &PP, Module *RootModule) {
       continue;
 
     const HeaderFileInfo *HFI = HS.getExistingLocalFileInfo(*File);
-    if (!HFI || (HFI->isModuleHeader && !HFI->isCompilingModuleHeader))
+    if (!HFI || ((HFI->isModuleHeader || HFI->isTextualModuleHeader) &&
+                 !HFI->isCompilingModuleHeader))
       continue;
 
     for (const auto &KH : HS.findResolvedModulesForHeader(*File)) {
@@ -2055,11 +2056,12 @@ void ASTWriter::WriteHeaderSearch(const HeaderSearch &HS) {
 
     // Get the file info. Skip emitting this file if we have no information on
     // it as a header file (in which case HFI will be null) or if it hasn't
-    // changed since it was loaded. Also skip it if it's for a modular header
-    // from a different module; in that case, we rely on the module(s)
+    // changed since it was loaded. Also skip it if it's for a non-excluded
+    // header from a different module; in that case, we rely on the module(s)
     // containing the header to provide this information.
     const HeaderFileInfo *HFI = HS.getExistingLocalFileInfo(*File);
-    if (!HFI || (HFI->isModuleHeader && !HFI->isCompilingModuleHeader))
+    if (!HFI || ((HFI->isModuleHeader || HFI->isTextualModuleHeader) &&
+                 !HFI->isCompilingModuleHeader))
       continue;
 
     // Massage the file path into an appropriate form.
diff --git a/clang/test/Modules/prune-non-affecting-module-map-files-textual.c b/clang/test/Modules/prune-non-affecting-module-map-files-textual.c
new file mode 100644
index 00000000000000..8f8f00560b1834
--- /dev/null
+++ b/clang/test/Modules/prune-non-affecting-module-map-files-textual.c
@@ -0,0 +1,26 @@
+// This test checks that a module map with a textual header can be marked as
+// non-affecting.
+
+// RUN: rm -rf %t && mkdir %t
+// RUN: split-file %s %t
+
+//--- A.modulemap
+module A { textual header "A.h" }
+//--- B.modulemap
+module B { header "B.h" export * }
+//--- A.h
+typedef int A_int;
+//--- B.h
+#include "A.h"
+typedef A_int B_int;
+
+// RUN: %clang_cc1 -fmodules -emit-module %t/A.modulemap -fmodule-name=A -o %t/A.pcm \
+// RUN:   -fmodule-map-file=%t/A.modulemap -fmodule-map-file=%t/B.modulemap
+
+// RUN: %clang_cc1 -fmodules -emit-module %t/B.modulemap -fmodule-name=B -o %t/B0.pcm \
+// RUN:   -fmodule-map-file=%t/A.modulemap -fmodule-map-file=%t/B.modulemap -fmodule-file=%t/A.pcm
+
+// RUN: %clang_cc1 -fmodules -emit-module %t/B.modulemap -fmodule-name=B -o %t/B1.pcm \
+// RUN:                                    -fmodule-map-file=%t/B.modulemap -fmodule-file=%t/A.pcm
+
+// RUN: diff %t/B0.pcm %t/B1.pcm

>From 17b1860b25de99f8b2b2e047ef1590b8ede6648b Mon Sep 17 00:00:00 2001
From: Jan Svoboda <jan_svoboda at apple.com>
Date: Mon, 22 Apr 2024 09:28:26 -0700
Subject: [PATCH 2/2] [clang][modules] Mark 'use'd modules as affecting

---
 clang/lib/Serialization/ASTWriter.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 4825c245a4b846..8c303fa67e3023 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -238,6 +238,8 @@ GetAffectingModuleMaps(const Preprocessor &PP, Module *RootModule) {
     CollectIncludingMapsFromAncestors(CurrentModule);
     for (const Module *ImportedModule : CurrentModule->Imports)
       CollectIncludingMapsFromAncestors(ImportedModule);
+    for (const Module *UsedModule : CurrentModule->DirectUses)
+      CollectIncludingMapsFromAncestors(UsedModule);
     for (const Module *UndeclaredModule : CurrentModule->UndeclaredUses)
       CollectIncludingMapsFromAncestors(UndeclaredModule);
   }