https://github.com/dmpolukhin updated
https://github.com/llvm/llvm-project/pull/132214
>From 91e057bf990e2c454b897982ed0b4e823bb3faba Mon Sep 17 00:00:00 2001
From: Dmitry Polukhin <dmitry.poluk...@gmail.com>
Date: Thu, 20 Mar 2025 06:51:46 -0700
Subject: [PATCH 1/5] [clang] Fix for regression #130917
Changes in #111992 was too broad. This change reduces scope of previous
fix. Unfortunately in clang there is no way to know when redeclaration
was craeted artificially due to AST mergse and when it was the case in
the original code.
---
.../lib/Sema/SemaTemplateInstantiateDecl.cpp | 2 +-
.../SemaCXX/friend-default-parameters.cpp | 21 +++++++++++++++++++
2 files changed, 22 insertions(+), 1 deletion(-)
create mode 100644 clang/test/SemaCXX/friend-default-parameters.cpp
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 539c2fdb83797..eda5d1151ab19 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2572,7 +2572,7 @@ Decl *TemplateDeclInstantiator::VisitFunctionDecl(
// Friend function defined withing class template may stop being function
// definition during AST merges from different modules, in this case decl
// with function body should be used for instantiation.
- if (isFriend) {
+ if (isFriend && D->hasOwningModule()) {
const FunctionDecl *Defn = nullptr;
if (D->hasBody(Defn)) {
D = const_cast<FunctionDecl *>(Defn);
diff --git a/clang/test/SemaCXX/friend-default-parameters.cpp
b/clang/test/SemaCXX/friend-default-parameters.cpp
new file mode 100644
index 0000000000000..7190477ac496a
--- /dev/null
+++ b/clang/test/SemaCXX/friend-default-parameters.cpp
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -std=c++20 -verify -emit-llvm-only %s
+
+template <int>
+void Create(const void* = nullptr);
+
+template <int>
+struct ObjImpl {
+ template <int>
+ friend void ::Create(const void*);
+};
+
+template <int I>
+void Create(const void*) {
+ (void) ObjImpl<I>{};
+}
+
+int main() {
+ Create<42>();
+}
+
+// expected-no-diagnostics
>From adf6dfde1c360747fca2befd40e3d225cfeb4970 Mon Sep 17 00:00:00 2001
From: Dmitry Polukhin <dmitry.poluk...@gmail.com>
Date: Tue, 25 Mar 2025 07:14:56 -0700
Subject: [PATCH 2/5] Add test case with C++ modules
---
.../friend-default-parameters-modules.cpp | 39 +++++++++++++++++++
1 file changed, 39 insertions(+)
create mode 100644 clang/test/SemaCXX/friend-default-parameters-modules.cpp
diff --git a/clang/test/SemaCXX/friend-default-parameters-modules.cpp
b/clang/test/SemaCXX/friend-default-parameters-modules.cpp
new file mode 100644
index 0000000000000..9c4aff9f1964a
--- /dev/null
+++ b/clang/test/SemaCXX/friend-default-parameters-modules.cpp
@@ -0,0 +1,39 @@
+// RUN: rm -fR %t
+// RUN: split-file %s %t
+// RUN: cd %t
+// RUN: %clang_cc1 -std=c++20 -fmodule-map-file=modules.map -xc++ -emit-module
-fmodule-name=foo modules.map -o foo.pcm
+// RUN: %clang_cc1 -std=c++20 -fmodule-map-file=modules.map -O1 -emit-obj
main.cc -verify -fmodule-file=foo.pcm
+
+//--- modules.map
+module "foo" {
+ export *
+ module "foo.h" {
+ export *
+ header "foo.h"
+ }
+}
+
+//--- foo.h
+#pragma once
+
+template <int>
+void Create(const void* = nullptr);
+
+template <int>
+struct ObjImpl {
+ template <int>
+ friend void ::Create(const void*);
+};
+
+template <int I>
+void Create(const void*) {
+ (void) ObjImpl<I>{};
+}
+
+//--- main.cc
+// expected-no-diagnostics
+#include "foo.h"
+
+int main() {
+ Create<42>();
+}
>From a564da2384ae1412647d1134aaf5359fe30e75a7 Mon Sep 17 00:00:00 2001
From: Dmitry Polukhin <dmitry.poluk...@gmail.com>
Date: Tue, 25 Mar 2025 08:26:49 -0700
Subject: [PATCH 3/5] Add flag to FunctionDecl
---
clang/include/clang/AST/Decl.h | 12 ++++++++++++
clang/lib/Sema/SemaTemplateInstantiateDecl.cpp | 2 +-
clang/lib/Serialization/ASTReader.cpp | 1 +
3 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
index efac36e49351e..9fdba31eb34ae 100644
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -2005,6 +2005,10 @@ class FunctionDecl : public DeclaratorDecl,
unsigned ODRHash;
+ /// Indicates if given function declaration was a definition but its body
+ /// was removed due to declaration merging.
+ bool ThisDeclarationWasADefinition : 1;
+
/// End part of this FunctionDecl's source range.
///
/// We could compute the full range in getSourceRange(). However, when we're
@@ -2190,6 +2194,14 @@ class FunctionDecl : public DeclaratorDecl,
return hasBody(Definition);
}
+ void setThisDeclarationWasADefinition() {
+ ThisDeclarationWasADefinition = true;
+ }
+
+ bool wasThisDeclarationADefinition() {
+ return ThisDeclarationWasADefinition;
+ }
+
/// Returns whether the function has a trivial body that does not require any
/// specific codegen.
bool hasTrivialBody() const;
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index eda5d1151ab19..90e81ab68f0f9 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -2572,7 +2572,7 @@ Decl *TemplateDeclInstantiator::VisitFunctionDecl(
// Friend function defined withing class template may stop being function
// definition during AST merges from different modules, in this case decl
// with function body should be used for instantiation.
- if (isFriend && D->hasOwningModule()) {
+ if (isFriend && D->wasThisDeclarationADefinition()) {
const FunctionDecl *Defn = nullptr;
if (D->hasBody(Defn)) {
D = const_cast<FunctionDecl *>(Defn);
diff --git a/clang/lib/Serialization/ASTReader.cpp
b/clang/lib/Serialization/ASTReader.cpp
index 2b03446aaa30e..0f676bbddab3f 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -10432,6 +10432,7 @@ void ASTReader::finishPendingActions() {
if (!getContext().getLangOpts().Modules || !FD->hasBody(Defn)) {
FD->setLazyBody(PB->second);
} else {
+ FD->setThisDeclarationWasADefinition();
auto *NonConstDefn = const_cast<FunctionDecl*>(Defn);
mergeDefinitionVisibility(NonConstDefn, FD);
>From 2b42b4d256f9abbc578aa8e92d21d02d50c83679 Mon Sep 17 00:00:00 2001
From: Dmitry Polukhin <dmitry.poluk...@gmail.com>
Date: Tue, 25 Mar 2025 08:32:47 -0700
Subject: [PATCH 4/5] Fix formatting
---
clang/include/clang/AST/Decl.h | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
index 9fdba31eb34ae..0d9760d3608b4 100644
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -2198,9 +2198,7 @@ class FunctionDecl : public DeclaratorDecl,
ThisDeclarationWasADefinition = true;
}
- bool wasThisDeclarationADefinition() {
- return ThisDeclarationWasADefinition;
- }
+ bool wasThisDeclarationADefinition() { return ThisDeclarationWasADefinition;
}
/// Returns whether the function has a trivial body that does not require any
/// specific codegen.
>From 8d5ecfd15ef1ac8fe576f515454eb683ad55c3f4 Mon Sep 17 00:00:00 2001
From: Dmitry Polukhin <dmitry.poluk...@gmail.com>
Date: Tue, 25 Mar 2025 10:05:38 -0700
Subject: [PATCH 5/5] Add missing initialization
---
clang/lib/AST/Decl.cpp | 1 +
1 file changed, 1 insertion(+)
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index e8aeacf24374f..aad54afa5488f 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -3083,6 +3083,7 @@ FunctionDecl::FunctionDecl(Kind DK, ASTContext &C,
DeclContext *DC,
static_cast<unsigned char>(DeductionCandidate::Normal);
FunctionDeclBits.HasODRHash = false;
FunctionDeclBits.FriendConstraintRefersToEnclosingTemplate = false;
+ ThisDeclarationWasADefinition = false;
if (TrailingRequiresClause)
setTrailingRequiresClause(TrailingRequiresClause);
}
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