https://github.com/ahatanak updated
https://github.com/llvm/llvm-project/pull/85886
>From d39667c7e65c10babb478d8f8d54fecb66d90568 Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahata...@gmail.com>
Date: Tue, 19 Mar 2024 15:50:00 -0700
Subject: [PATCH 1/5] [Sema] Don't drop weak_import from a declaration that
follows a declaration directly contained in a linkage-specification
Only drop it if the declaration follows a definition. I believe this is
what 33e022650adee965c65f9aea086ee74f3fd1bad5 was trying to do.
rdar://61865848
---
clang/lib/Sema/SemaDecl.cpp | 3 +--
clang/test/SemaCXX/attr-weak.cpp | 7 +++++++
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 5850cd0ab6b9a..2e45f1191273a 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -4613,8 +4613,7 @@ void Sema::MergeVarDecl(VarDecl *New, LookupResult
&Previous) {
mergeDeclAttributes(New, Old);
// Warn if an already-declared variable is made a weak_import in a subsequent
// declaration
- if (New->hasAttr<WeakImportAttr>() &&
- Old->getStorageClass() == SC_None &&
+ if (New->hasAttr<WeakImportAttr>() && Old->isThisDeclarationADefinition() &&
!Old->hasAttr<WeakImportAttr>()) {
Diag(New->getLocation(), diag::warn_weak_import) << New->getDeclName();
Diag(Old->getLocation(), diag::note_previous_declaration);
diff --git a/clang/test/SemaCXX/attr-weak.cpp b/clang/test/SemaCXX/attr-weak.cpp
index f065bfd9483f8..a2c5fd4abd35f 100644
--- a/clang/test/SemaCXX/attr-weak.cpp
+++ b/clang/test/SemaCXX/attr-weak.cpp
@@ -55,3 +55,10 @@ constexpr bool weak_method_is_non_null =
&WithWeakMember::weak_method != nullptr
// virtual member function is present.
constexpr bool virtual_weak_method_is_non_null =
&WithWeakMember::virtual_weak_method != nullptr; // expected-error {{must be
initialized by a constant expression}}
// expected-note@-1 {{comparison against pointer to weak member
'WithWeakMember::virtual_weak_method' can only be performed at runtime}}
+
+// Check that no warnings are emitted.
+extern "C" int g0;
+extern int g0 __attribute__((weak_import));
+
+extern "C" int g1 = 0; // expected-note {{previous definition is here}}
+extern int g1 __attribute__((weak_import)); // expected-warning {{attribute
declaration must precede definition}}
>From 33e3219c721d0c03f445c9bb977cb9f3809e74ac Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahata...@gmail.com>
Date: Wed, 8 May 2024 20:40:58 -0700
Subject: [PATCH 2/5] Check whether there's a definition at all
---
clang/lib/Sema/SemaDecl.cpp | 23 +++++++++++++++++------
clang/test/Sema/attr-weak.c | 4 ++++
2 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 2e45f1191273a..0be6906026a85 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -4613,12 +4613,23 @@ void Sema::MergeVarDecl(VarDecl *New, LookupResult
&Previous) {
mergeDeclAttributes(New, Old);
// Warn if an already-declared variable is made a weak_import in a subsequent
// declaration
- if (New->hasAttr<WeakImportAttr>() && Old->isThisDeclarationADefinition() &&
- !Old->hasAttr<WeakImportAttr>()) {
- Diag(New->getLocation(), diag::warn_weak_import) << New->getDeclName();
- Diag(Old->getLocation(), diag::note_previous_declaration);
- // Remove weak_import attribute on new declaration.
- New->dropAttr<WeakImportAttr>();
+ if (New->hasAttr<WeakImportAttr>()) {
+ // We know there's no full definition as the attribute on New would have
+ // been removed otherwise. Just look for the most recent tentative
+ // definition.
+ VarDecl *TentativeDef = nullptr;
+ for (auto *D = Old; D; D = D->getPreviousDecl())
+ if (D->isThisDeclarationADefinition() == VarDecl::TentativeDefinition) {
+ TentativeDef = D;
+ break;
+ }
+
+ if (TentativeDef) {
+ Diag(New->getLocation(), diag::warn_weak_import) << New->getDeclName();
+ Diag(TentativeDef->getLocation(), diag::note_previous_declaration);
+ // Remove weak_import attribute on new declaration.
+ New->dropAttr<WeakImportAttr>();
+ }
}
if (const auto *ILA = New->getAttr<InternalLinkageAttr>())
diff --git a/clang/test/Sema/attr-weak.c b/clang/test/Sema/attr-weak.c
index b827d1539b997..94e1723e125b6 100644
--- a/clang/test/Sema/attr-weak.c
+++ b/clang/test/Sema/attr-weak.c
@@ -19,6 +19,10 @@ static int x __attribute__((weak)); // expected-error {{weak
declaration cannot
int C; // expected-note {{previous declaration is here}}
extern int C __attribute__((weak_import)); // expected-warning {{an
already-declared variable is made a weak_import declaration}}
+int C2; // expected-note {{previous declaration is here}}
+extern int C2;
+extern int C2 __attribute__((weak_import)); // expected-warning {{an
already-declared variable is made a weak_import declaration}}
+
static int pr14946_x;
extern int pr14946_x __attribute__((weak)); // expected-error {{weak
declaration cannot have internal linkage}}
>From c33375cbc8863be911f7832538228cfde0e1d58d Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahata...@gmail.com>
Date: Thu, 9 May 2024 07:44:54 -0700
Subject: [PATCH 3/5] Improve the diagnostic message and check that the decl
isn't DeclarationOnly
---
.../clang/Basic/DiagnosticSemaKinds.td | 2 +-
clang/lib/Sema/SemaDecl.cpp | 24 +++++++------------
clang/test/Sema/attr-weak.c | 4 ++--
3 files changed, 11 insertions(+), 19 deletions(-)
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 8e97902564af0..687b1678f6923 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -6018,7 +6018,7 @@ def note_extern_c_global_conflict : Note<
def note_extern_c_begins_here : Note<
"extern \"C\" language linkage specification begins here">;
def warn_weak_import : Warning <
- "an already-declared variable is made a weak_import declaration %0">;
+ "an already-defined variable is made a weak_import declaration %0">;
def ext_static_non_static : Extension<
"redeclaring non-static %0 as static is a Microsoft extension">,
InGroup<MicrosoftRedeclareStatic>;
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 0be6906026a85..84cc8c6b64443 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -4611,26 +4611,18 @@ void Sema::MergeVarDecl(VarDecl *New, LookupResult
&Previous) {
}
mergeDeclAttributes(New, Old);
- // Warn if an already-declared variable is made a weak_import in a subsequent
+ // Warn if an already-defined variable is made a weak_import in a subsequent
// declaration
- if (New->hasAttr<WeakImportAttr>()) {
- // We know there's no full definition as the attribute on New would have
- // been removed otherwise. Just look for the most recent tentative
- // definition.
- VarDecl *TentativeDef = nullptr;
- for (auto *D = Old; D; D = D->getPreviousDecl())
- if (D->isThisDeclarationADefinition() == VarDecl::TentativeDefinition) {
- TentativeDef = D;
+ if (New->hasAttr<WeakImportAttr>())
+ for (auto *D = Old; D; D = D->getPreviousDecl()) {
+ if (D->isThisDeclarationADefinition() != VarDecl::DeclarationOnly) {
+ Diag(New->getLocation(), diag::warn_weak_import) << New->getDeclName();
+ Diag(D->getLocation(), diag::note_previous_declaration);
+ // Remove weak_import attribute on new declaration.
+ New->dropAttr<WeakImportAttr>();
break;
}
-
- if (TentativeDef) {
- Diag(New->getLocation(), diag::warn_weak_import) << New->getDeclName();
- Diag(TentativeDef->getLocation(), diag::note_previous_declaration);
- // Remove weak_import attribute on new declaration.
- New->dropAttr<WeakImportAttr>();
}
- }
if (const auto *ILA = New->getAttr<InternalLinkageAttr>())
if (!Old->hasAttr<InternalLinkageAttr>()) {
diff --git a/clang/test/Sema/attr-weak.c b/clang/test/Sema/attr-weak.c
index 94e1723e125b6..3dbf46e65d05b 100644
--- a/clang/test/Sema/attr-weak.c
+++ b/clang/test/Sema/attr-weak.c
@@ -17,11 +17,11 @@ static int f(void) __attribute__((weak)); // expected-error
{{weak declaration c
static int x __attribute__((weak)); // expected-error {{weak declaration
cannot have internal linkage}}
int C; // expected-note {{previous declaration is here}}
-extern int C __attribute__((weak_import)); // expected-warning {{an
already-declared variable is made a weak_import declaration}}
+extern int C __attribute__((weak_import)); // expected-warning {{an
already-defined variable is made a weak_import declaration}}
int C2; // expected-note {{previous declaration is here}}
extern int C2;
-extern int C2 __attribute__((weak_import)); // expected-warning {{an
already-declared variable is made a weak_import declaration}}
+extern int C2 __attribute__((weak_import)); // expected-warning {{an
already-defined variable is made a weak_import declaration}}
static int pr14946_x;
extern int pr14946_x __attribute__((weak)); // expected-error {{weak
declaration cannot have internal linkage}}
>From 0f18a7a7007967c231221b8eeacde265e1d0302d Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahata...@gmail.com>
Date: Thu, 9 May 2024 09:31:34 -0700
Subject: [PATCH 4/5] Fix note message
---
clang/lib/Sema/SemaDecl.cpp | 2 +-
clang/test/Sema/attr-weak.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 84cc8c6b64443..e2b143d0faca1 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -4617,7 +4617,7 @@ void Sema::MergeVarDecl(VarDecl *New, LookupResult
&Previous) {
for (auto *D = Old; D; D = D->getPreviousDecl()) {
if (D->isThisDeclarationADefinition() != VarDecl::DeclarationOnly) {
Diag(New->getLocation(), diag::warn_weak_import) << New->getDeclName();
- Diag(D->getLocation(), diag::note_previous_declaration);
+ Diag(D->getLocation(), diag::note_previous_definition);
// Remove weak_import attribute on new declaration.
New->dropAttr<WeakImportAttr>();
break;
diff --git a/clang/test/Sema/attr-weak.c b/clang/test/Sema/attr-weak.c
index 3dbf46e65d05b..9e343760ea887 100644
--- a/clang/test/Sema/attr-weak.c
+++ b/clang/test/Sema/attr-weak.c
@@ -16,10 +16,10 @@ struct __attribute__((weak_import)) s1 {}; //
expected-warning {{'weak_import' a
static int f(void) __attribute__((weak)); // expected-error {{weak declaration
cannot have internal linkage}}
static int x __attribute__((weak)); // expected-error {{weak declaration
cannot have internal linkage}}
-int C; // expected-note {{previous declaration is here}}
+int C; // expected-note {{previous definition is here}}
extern int C __attribute__((weak_import)); // expected-warning {{an
already-defined variable is made a weak_import declaration}}
-int C2; // expected-note {{previous declaration is here}}
+int C2; // expected-note {{previous definition is here}}
extern int C2;
extern int C2 __attribute__((weak_import)); // expected-warning {{an
already-defined variable is made a weak_import declaration}}
>From 0fcd6d80aee34ce0eaacc3c2c6712d42e587d232 Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahata...@gmail.com>
Date: Wed, 17 Jul 2024 14:54:11 -0700
Subject: [PATCH 5/5] Improve diagnostic wording
---
clang/include/clang/Basic/DiagnosticSemaKinds.td | 2 +-
clang/test/Sema/attr-weak.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 687b1678f6923..40cea8bf29990 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -6018,7 +6018,7 @@ def note_extern_c_global_conflict : Note<
def note_extern_c_begins_here : Note<
"extern \"C\" language linkage specification begins here">;
def warn_weak_import : Warning <
- "an already-defined variable is made a weak_import declaration %0">;
+ "%0 cannot be declared 'weak_import' because its definition has been
provided">;
def ext_static_non_static : Extension<
"redeclaring non-static %0 as static is a Microsoft extension">,
InGroup<MicrosoftRedeclareStatic>;
diff --git a/clang/test/Sema/attr-weak.c b/clang/test/Sema/attr-weak.c
index 9e343760ea887..f6482109bc9f6 100644
--- a/clang/test/Sema/attr-weak.c
+++ b/clang/test/Sema/attr-weak.c
@@ -17,11 +17,11 @@ static int f(void) __attribute__((weak)); // expected-error
{{weak declaration c
static int x __attribute__((weak)); // expected-error {{weak declaration
cannot have internal linkage}}
int C; // expected-note {{previous definition is here}}
-extern int C __attribute__((weak_import)); // expected-warning {{an
already-defined variable is made a weak_import declaration}}
+extern int C __attribute__((weak_import)); // expected-warning {{'C' cannot be
declared 'weak_import'}}
int C2; // expected-note {{previous definition is here}}
extern int C2;
-extern int C2 __attribute__((weak_import)); // expected-warning {{an
already-defined variable is made a weak_import declaration}}
+extern int C2 __attribute__((weak_import)); // expected-warning {{'C2' cannot
be declared 'weak_import'}}
static int pr14946_x;
extern int pr14946_x __attribute__((weak)); // expected-error {{weak
declaration cannot have internal linkage}}
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