[clang] [C++20][Modules] Fix incomplete decl chains (PR #129982)
Michael Park via cfe-commits
cfe-commits at lists.llvm.org
Wed Mar 5 20:21:56 PST 2025
https://github.com/mpark updated https://github.com/llvm/llvm-project/pull/129982
>From 3f883067a2fda4147003de9a53b88e52c33d1280 Mon Sep 17 00:00:00 2001
From: Michael Park <mcypark at gmail.com>
Date: Tue, 25 Feb 2025 14:33:41 -0800
Subject: [PATCH 1/3] =?UTF-8?q?Reapply=20"[C++20][Modules][Serialization]?=
=?UTF-8?q?=20Delay=20marking=20pending=20incompl=E2=80=A6=20(#127136)?=
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This reverts commit 912b154f3a3f8c3cebf5cc5731fd8b0749762da5.
---
clang/lib/Serialization/ASTReader.cpp | 25 ++++---
clang/test/Modules/pr121245.cpp | 93 +++++++++++++++++++++++++++
2 files changed, 105 insertions(+), 13 deletions(-)
create mode 100644 clang/test/Modules/pr121245.cpp
diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index ca09c3d79d941..17d07f8535346 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -10178,12 +10178,12 @@ void ASTReader::visitTopLevelModuleMaps(
}
void ASTReader::finishPendingActions() {
- while (
- !PendingIdentifierInfos.empty() || !PendingDeducedFunctionTypes.empty() ||
- !PendingDeducedVarTypes.empty() || !PendingIncompleteDeclChains.empty() ||
- !PendingDeclChains.empty() || !PendingMacroIDs.empty() ||
- !PendingDeclContextInfos.empty() || !PendingUpdateRecords.empty() ||
- !PendingObjCExtensionIvarRedeclarations.empty()) {
+ while (!PendingIdentifierInfos.empty() ||
+ !PendingDeducedFunctionTypes.empty() ||
+ !PendingDeducedVarTypes.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 =
@@ -10231,13 +10231,6 @@ 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,
@@ -10475,6 +10468,12 @@ 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
new file mode 100644
index 0000000000000..0e276ad0e435d
--- /dev/null
+++ b/clang/test/Modules/pr121245.cpp
@@ -0,0 +1,93 @@
+// 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();
+}
>From bd07e7b713169676e78e0c9382e66d97b70e8d58 Mon Sep 17 00:00:00 2001
From: Michael Park <mcypark at gmail.com>
Date: Wed, 5 Mar 2025 18:46:10 -0800
Subject: [PATCH 2/3] Add a unit test that reproduces the assertion failure
during bootstrap build on OS X with XCode.
---
clang/test/Modules/pr129982.cpp | 107 ++++++++++++++++++++++++++++++++
1 file changed, 107 insertions(+)
create mode 100644 clang/test/Modules/pr129982.cpp
diff --git a/clang/test/Modules/pr129982.cpp b/clang/test/Modules/pr129982.cpp
new file mode 100644
index 0000000000000..b19cccfd07687
--- /dev/null
+++ b/clang/test/Modules/pr129982.cpp
@@ -0,0 +1,107 @@
+// If this test fails, it should be investigated under Debug builds.
+// Before the PR, this test was violating an assertion.
+
+// RUN: rm -rf %t
+// RUN: mkdir -p %t
+// RUN: split-file %s %t
+
+// RUN: %clang_cc1 -std=c++20 -emit-obj -fmodules \
+// RUN: -fmodule-map-file=%t/module.modulemap \
+// RUN: -fmodules-cache-path=%t %t/a.cpp
+
+//--- module.modulemap
+module ebo {
+ header "ebo.h"
+}
+
+module fwd {
+ header "fwd.h"
+}
+
+module s {
+ header "s.h"
+ export *
+}
+
+module mod {
+ header "a.h"
+ header "b.h"
+}
+
+//--- ebo.h
+#pragma once
+
+namespace N { inline namespace __1 {
+
+template <typename T>
+struct EBO : T {
+ EBO() = default;
+};
+
+}}
+
+//--- fwd.h
+#pragma once
+
+namespace N { inline namespace __1 {
+
+template <typename T>
+struct Empty;
+
+template <typename T>
+struct BS;
+
+using S = BS<Empty<char>>;
+
+}}
+
+//--- s.h
+#pragma once
+
+#include "fwd.h"
+#include "ebo.h"
+
+namespace N { inline namespace __1 {
+
+template <typename T>
+struct Empty {};
+
+template <typename T>
+struct BS {
+ EBO<T> _;
+ void f();
+};
+
+extern template void BS<Empty<char>>::f();
+
+}}
+
+//--- b.h
+#pragma once
+
+#include "s.h"
+
+struct B {
+ void f() {
+ N::S{}.f();
+ }
+};
+
+//--- a.h
+#pragma once
+
+#include "s.h"
+
+struct A {
+ void f(int) {}
+ void f(const N::S &) {}
+
+ void g();
+};
+
+//--- a.cpp
+#include "a.h"
+
+void A::g() { f(0); }
+
+// expected-no-diagnostics
>From d6dbfd6f01710b8fed2303e66f60903efd2283f2 Mon Sep 17 00:00:00 2001
From: Michael Park <mcypark at gmail.com>
Date: Wed, 5 Mar 2025 18:48:12 -0800
Subject: [PATCH 3/3] Complete the redecl chain.
---
clang/lib/Sema/SemaType.cpp | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 11943c0b53591..e2002bb410110 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -9180,6 +9180,12 @@ bool Sema::hasAcceptableDefinition(NamedDecl *D, NamedDecl **Suggested,
if (!getLangOpts().Modules && !getLangOpts().ModulesLocalVisibility)
return true;
+ // The external source may have additional definitions of this entity that are
+ // visible, so complete the redeclaration chain now.
+ if (auto *Source = Context.getExternalSource()) {
+ Source->CompleteRedeclChain(D);
+ }
+
// If this definition was instantiated from a template, map back to the
// pattern from which it was instantiated.
if (isa<TagDecl>(D) && cast<TagDecl>(D)->isBeingDefined()) {
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