[clang] [clang] fix merging of UsingShadowDecl (PR #80245)
Matheus Izvekov via cfe-commits
cfe-commits at lists.llvm.org
Thu Feb 1 21:30:19 PST 2024
https://github.com/mizvekov updated https://github.com/llvm/llvm-project/pull/80245
>From 7bd920a14240c85442467706236e0644f320aa5c Mon Sep 17 00:00:00 2001
From: Matheus Izvekov <mizvekov at gmail.com>
Date: Thu, 1 Feb 2024 02:07:16 -0300
Subject: [PATCH 1/2] [NFC] [clang] add tests for merging of UsingShadowDecl
---
clang/test/Modules/GH80252.cppm | 45 +++++++++++++++++++++++++++++
clang/test/Modules/cxx20-decls.cppm | 44 ++++++++++++++++++++++++++++
2 files changed, 89 insertions(+)
create mode 100644 clang/test/Modules/GH80252.cppm
create mode 100644 clang/test/Modules/cxx20-decls.cppm
diff --git a/clang/test/Modules/GH80252.cppm b/clang/test/Modules/GH80252.cppm
new file mode 100644
index 0000000000000..f4730a9874197
--- /dev/null
+++ b/clang/test/Modules/GH80252.cppm
@@ -0,0 +1,45 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: cd %t
+//
+// RUN: %clang_cc1 -std=c++20 -I %t %t/A.cppm -emit-module-interface -o %t/A.pcm -verify
+// RUN: %clang_cc1 -std=c++20 -I %t %t/B.cppm -emit-module-interface -o %t/B.pcm -verify
+// RUN: %clang_cc1 -std=c++20 -I %t %t/C.cpp -fmodule-file=A=%t/A.pcm -fmodule-file=B=%t/B.pcm -fsyntax-only -verify
+
+//--- foo.h
+namespace baz {
+ using foo = char;
+ using baz::foo;
+}
+
+//--- bar.h
+class bar {
+ bar(baz::foo);
+};
+
+//--- A.cppm
+// expected-no-diagnostics
+module;
+#include "foo.h"
+export module A;
+export using AX = baz::foo;
+
+//--- B.cppm
+// expected-no-diagnostics
+module;
+#include "foo.h"
+#include "bar.h"
+export module B;
+export using BX = baz::foo;
+export using BY = bar;
+
+//--- C.cpp
+#include "foo.h"
+import A;
+#include "bar.h"
+import B;
+// Since modules are loaded lazily, force loading by performing a lookup.
+using xxx = bar;
+// FIXME: This is a false positive ODR violation.
+// expected-error at bar.h:2 {{'bar' has different definitions in different modules; first difference is defined here found constructor with 1st parameter of type 'baz::foo' (aka 'char')}}
+// expected-note at bar.h:2 {{but in 'B.<global>' found constructor with 1st parameter of type 'baz::foo' (aka 'char')}}
diff --git a/clang/test/Modules/cxx20-decls.cppm b/clang/test/Modules/cxx20-decls.cppm
new file mode 100644
index 0000000000000..28af7b4bc47b4
--- /dev/null
+++ b/clang/test/Modules/cxx20-decls.cppm
@@ -0,0 +1,44 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: cd %t
+//
+// RUN: %clang_cc1 -std=c++20 -I %t %t/A.cppm -emit-module-interface -o %t/A.pcm -verify
+// RUN: %clang_cc1 -std=c++20 -I %t %t/B.cpp -fmodule-file=A=%t/A.pcm -fsyntax-only -verify -ast-dump-all -ast-dump-filter baz | FileCheck %s
+
+//--- foo.h
+namespace baz {
+ using foo = char;
+ using baz::foo;
+}
+
+//--- A.cppm
+// expected-no-diagnostics
+module;
+#include "foo.h"
+export module A;
+
+//--- B.cpp
+// expected-no-diagnostics
+#include "foo.h"
+import A;
+// Since modules are loaded lazily, force loading by performing a lookup.
+using xxx = baz::foo;
+
+// CHECK-LABEL: Dumping baz:
+// CHECK-NEXT: NamespaceDecl {{.*}} imported in A.<global> {{.*}} baz
+// CHECK-NEXT: |-original Namespace {{.*}} 'baz'
+// CHECK-NEXT: |-TypeAliasDecl {{.*}} foo 'char'
+// CHECK-NEXT: | `-BuiltinType {{.*}} 'char'
+// CHECK-NEXT: |-UsingDecl {{.*}} baz::foo
+// CHECK-NEXT: | `-NestedNameSpecifier Namespace {{.*}} 'baz'
+// FIXME: UsingShadowDecl should have been merged
+// CHECK-NOT: `-UsingShadowDecl 0x{{[^ ]*}} prev 0x{{[^ ]*}} {{.*}} imported in A.<global> {{.*}} 'foo'
+// CHECK-NEXT: `-UsingShadowDecl 0x{{[^ ]*}} {{.*}} imported in A.<global> {{.*}} 'foo'
+
+// CHECK-LABEL: Dumping baz:
+// CHECK-NEXT: NamespaceDecl {{.*}} baz
+// CHECK-NEXT: |-TypeAliasDecl {{.*}} foo 'char'
+// CHECK-NEXT: | `-BuiltinType {{.*}} 'char'
+// CHECK-NEXT: |-UsingDecl {{.*}} baz::foo
+// CHECK-NEXT: | `-NestedNameSpecifier Namespace {{.*}} 'baz'
+// CHECK-NEXT: `-UsingShadowDecl 0x[[SHADOW_ADDR:[^ ]*]] {{.*}} 'foo'
>From db966f66a148ab5b5ba26250cbf0dab6be5a2c29 Mon Sep 17 00:00:00 2001
From: Matheus Izvekov <mizvekov at gmail.com>
Date: Thu, 1 Feb 2024 02:26:10 -0300
Subject: [PATCH 2/2] [clang] fix merging of UsingShadowDecl
Previously, when deciding if two UsingShadowDecls where mergeable,
we would incorrectly only look for both pointing to the exact redecla
ration, whereas the correct thing is to look for declarations to the
same entity.
This problem has existed as far back as 2013, introduced in commit
fd8634a09de71.
This problem could manifest itself as ODR check false positives
when importing modules.
Fixes: #80252
---
clang/docs/ReleaseNotes.rst | 3 +++
clang/lib/AST/ASTContext.cpp | 2 +-
clang/test/Modules/GH80252.cppm | 4 +---
clang/test/Modules/cxx20-decls.cppm | 6 ++----
4 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 53040aa0f9074..0a9cd242f9d95 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -188,6 +188,9 @@ Bug Fixes to C++ Support
and (`#79745 <https://github.com/llvm/llvm-project/issues/79745>`_)
- Fix incorrect code generation caused by the object argument of ``static operator()`` and ``static operator[]`` calls not being evaluated.
Fixes (`#67976 <https://github.com/llvm/llvm-project/issues/67976>`_)
+- Fix incorrect merging of modules which contain using declarations which shadow
+ other declarations. This could manifest as ODR checker false positives.
+ Fixes (`#80252 <https://github.com/llvm/llvm-project/issues/80252>`_)
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 78a04b4c69426..f3e83955c429a 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -6733,7 +6733,7 @@ bool ASTContext::isSameEntity(const NamedDecl *X, const NamedDecl *Y) const {
// Using shadow declarations with the same target match.
if (const auto *USX = dyn_cast<UsingShadowDecl>(X)) {
const auto *USY = cast<UsingShadowDecl>(Y);
- return USX->getTargetDecl() == USY->getTargetDecl();
+ return declaresSameEntity(USX->getTargetDecl(), USY->getTargetDecl());
}
// Using declarations with the same qualifier match. (We already know that
diff --git a/clang/test/Modules/GH80252.cppm b/clang/test/Modules/GH80252.cppm
index f4730a9874197..dbad18dfdc7a2 100644
--- a/clang/test/Modules/GH80252.cppm
+++ b/clang/test/Modules/GH80252.cppm
@@ -40,6 +40,4 @@ import A;
import B;
// Since modules are loaded lazily, force loading by performing a lookup.
using xxx = bar;
-// FIXME: This is a false positive ODR violation.
-// expected-error at bar.h:2 {{'bar' has different definitions in different modules; first difference is defined here found constructor with 1st parameter of type 'baz::foo' (aka 'char')}}
-// expected-note at bar.h:2 {{but in 'B.<global>' found constructor with 1st parameter of type 'baz::foo' (aka 'char')}}
+// expected-no-diagnostics
diff --git a/clang/test/Modules/cxx20-decls.cppm b/clang/test/Modules/cxx20-decls.cppm
index 28af7b4bc47b4..477d519b50448 100644
--- a/clang/test/Modules/cxx20-decls.cppm
+++ b/clang/test/Modules/cxx20-decls.cppm
@@ -31,9 +31,7 @@ using xxx = baz::foo;
// CHECK-NEXT: | `-BuiltinType {{.*}} 'char'
// CHECK-NEXT: |-UsingDecl {{.*}} baz::foo
// CHECK-NEXT: | `-NestedNameSpecifier Namespace {{.*}} 'baz'
-// FIXME: UsingShadowDecl should have been merged
-// CHECK-NOT: `-UsingShadowDecl 0x{{[^ ]*}} prev 0x{{[^ ]*}} {{.*}} imported in A.<global> {{.*}} 'foo'
-// CHECK-NEXT: `-UsingShadowDecl 0x{{[^ ]*}} {{.*}} imported in A.<global> {{.*}} 'foo'
+// CHECK-NEXT: `-UsingShadowDecl 0x{{[^ ]*}} prev 0x[[SHADOW_ADDR:[^ ]*]] {{.*}} imported in A.<global> {{.*}} 'foo'
// CHECK-LABEL: Dumping baz:
// CHECK-NEXT: NamespaceDecl {{.*}} baz
@@ -41,4 +39,4 @@ using xxx = baz::foo;
// CHECK-NEXT: | `-BuiltinType {{.*}} 'char'
// CHECK-NEXT: |-UsingDecl {{.*}} baz::foo
// CHECK-NEXT: | `-NestedNameSpecifier Namespace {{.*}} 'baz'
-// CHECK-NEXT: `-UsingShadowDecl 0x[[SHADOW_ADDR:[^ ]*]] {{.*}} 'foo'
+// CHECK-NEXT: `-UsingShadowDecl 0x[[SHADOW_ADDR]] {{.*}} 'foo'
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