[clang] Revert "[C++20][Modules][Serialization] Delay marking pending incompl… (PR #127136)

[Zixu Wang via cfe-commits]

https://github.com/zixu-w created https://github.com/llvm/llvm-project/pull/127136

…ete decl chains until the end of `finishPendingActions`. (#121245)"

This reverts commit a9e249f64e800fbb20a3b26c0cfb68c1a1aee5e1.

Reverting this change because of issue #126973.

>From 63db52efccafa7716cb6b6f07bfc482cbe172388 Mon Sep 17 00:00:00 2001
From: Zixu Wang <zixu_wang at apple.com>
Date: Thu, 13 Feb 2025 14:13:19 -0800
Subject: [PATCH] Revert "[C++20][Modules][Serialization] Delay marking pending
 incomplete decl chains until the end of `finishPendingActions`. (#121245)"

This reverts commit a9e249f64e800fbb20a3b26c0cfb68c1a1aee5e1.

Reverting this change because of issue #126973.
---
 clang/lib/Serialization/ASTReader.cpp | 25 +++----
 clang/test/Modules/pr121245.cpp       | 93 ---------------------------
 2 files changed, 13 insertions(+), 105 deletions(-)
 delete mode 100644 clang/test/Modules/pr121245.cpp

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index 3c64b67503195..4a40df6399f64 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -10188,12 +10188,12 @@ void ASTReader::visitTopLevelModuleMaps(
 }
 
 void ASTReader::finishPendingActions() {
-  while (!PendingIdentifierInfos.empty() ||
-         !PendingDeducedFunctionTypes.empty() ||
-         !PendingDeducedVarTypes.empty() || !PendingDeclChains.empty() ||
-         !PendingMacroIDs.empty() || !PendingDeclContextInfos.empty() ||
-         !PendingUpdateRecords.empty() ||
-         !PendingObjCExtensionIvarRedeclarations.empty()) {
+  while (
+      !PendingIdentifierInfos.empty() || !PendingDeducedFunctionTypes.empty() ||
+      !PendingDeducedVarTypes.empty() || !PendingIncompleteDeclChains.empty() ||
+      !PendingDeclChains.empty() || !PendingMacroIDs.empty() ||
+      !PendingDeclContextInfos.empty() || !PendingUpdateRecords.empty() ||
+      !PendingObjCExtensionIvarRedeclarations.empty()) {
     // If any identifiers with corresponding top-level declarations have
     // been loaded, load those declarations now.
     using TopLevelDeclsMap =
@@ -10241,6 +10241,13 @@ void ASTReader::finishPendingActions() {
     }
     PendingDeducedVarTypes.clear();
 
+    // For each decl chain that we wanted to complete while deserializing, mark
+    // it as "still needs to be completed".
+    for (unsigned I = 0; I != PendingIncompleteDeclChains.size(); ++I) {
+      markIncompleteDeclChain(PendingIncompleteDeclChains[I]);
+    }
+    PendingIncompleteDeclChains.clear();
+
     // Load pending declaration chains.
     for (unsigned I = 0; I != PendingDeclChains.size(); ++I)
       loadPendingDeclChain(PendingDeclChains[I].first,
@@ -10478,12 +10485,6 @@ void ASTReader::finishPendingActions() {
   for (auto *ND : PendingMergedDefinitionsToDeduplicate)
     getContext().deduplicateMergedDefinitonsFor(ND);
   PendingMergedDefinitionsToDeduplicate.clear();
-
-  // For each decl chain that we wanted to complete while deserializing, mark
-  // it as "still needs to be completed".
-  for (Decl *D : PendingIncompleteDeclChains)
-    markIncompleteDeclChain(D);
-  PendingIncompleteDeclChains.clear();
 }
 
 void ASTReader::diagnoseOdrViolations() {
diff --git a/clang/test/Modules/pr121245.cpp b/clang/test/Modules/pr121245.cpp
deleted file mode 100644
index 0e276ad0e435d..0000000000000
--- a/clang/test/Modules/pr121245.cpp
+++ /dev/null
@@ -1,93 +0,0 @@
-// If this test fails, it should be investigated under Debug builds.
-// Before the PR, this test was encountering an `llvm_unreachable()`.
-
-// RUN: rm -rf %t
-// RUN: mkdir -p %t
-// RUN: split-file %s %t
-// RUN: cd %t
-
-// RUN: %clang_cc1 -std=c++20 -emit-header-unit -xc++-user-header %t/hu-01.h \
-// RUN:  -fcxx-exceptions -o %t/hu-01.pcm
-
-// RUN: %clang_cc1 -std=c++20 -emit-header-unit -xc++-user-header %t/hu-02.h \
-// RUN:  -Wno-experimental-header-units -fcxx-exceptions \
-// RUN:  -fmodule-file=%t/hu-01.pcm -o %t/hu-02.pcm
-
-// RUN: %clang_cc1 -std=c++20 -emit-header-unit -xc++-user-header %t/hu-03.h \
-// RUN:  -Wno-experimental-header-units -fcxx-exceptions \
-// RUN:  -fmodule-file=%t/hu-01.pcm -o %t/hu-03.pcm
-
-// RUN: %clang_cc1 -std=c++20 -emit-header-unit -xc++-user-header %t/hu-04.h \
-// RUN:  -Wno-experimental-header-units -fcxx-exceptions \
-// RUN:  -fmodule-file=%t/hu-01.pcm -o %t/hu-04.pcm
-
-// RUN: %clang_cc1 -std=c++20 -emit-header-unit -xc++-user-header %t/hu-05.h \
-// RUN:  -Wno-experimental-header-units -fcxx-exceptions \
-// RUN:  -fmodule-file=%t/hu-03.pcm -fmodule-file=%t/hu-04.pcm \
-// RUN:  -fmodule-file=%t/hu-01.pcm -o %t/hu-05.pcm
-
-// RUN: %clang_cc1 -std=c++20 -emit-obj %t/main.cpp \
-// RUN:  -Wno-experimental-header-units -fcxx-exceptions \
-// RUN:  -fmodule-file=%t/hu-02.pcm -fmodule-file=%t/hu-05.pcm \
-// RUN:  -fmodule-file=%t/hu-04.pcm -fmodule-file=%t/hu-03.pcm \
-// RUN:  -fmodule-file=%t/hu-01.pcm
-
-//--- hu-01.h
-template <typename T>
-struct A {
-  A() {}
-  ~A() {}
-};
-
-template <typename T>
-struct EBO : T {
-  EBO() = default;
-};
-
-template <typename T>
-struct HT : EBO<A<T>> {};
-
-//--- hu-02.h
-import "hu-01.h";
-
-inline void f() {
-  HT<int>();
-}
-
-//--- hu-03.h
-import "hu-01.h";
-
-struct C {
-  C();
-
-  HT<long> _;
-};
-
-//--- hu-04.h
-import "hu-01.h";
-
-void g(HT<long> = {});
-
-//--- hu-05.h
-import "hu-03.h";
-import "hu-04.h";
-import "hu-01.h";
-
-struct B {
-  virtual ~B() = default;
-
-  virtual void f() {
-    HT<long>();
-  }
-};
-
-//--- main.cpp
-import "hu-02.h";
-import "hu-05.h";
-import "hu-03.h";
-
-int main() {
-  f();
-  C();
-  B();
-}