diff options
| author | Anders Waldenborg <anders@0x63.nu> | 2022-05-24 21:46:32 +0200 |
|---|---|---|
| committer | Anders Waldenborg <anders@0x63.nu> | 2022-06-03 23:44:15 +0200 |
| commit | dd2362a8bab312dffc42bfcb30ad1340840ef581 (patch) | |
| tree | 37cbdaf8d6960dbbf381ac0f3b50c99f1f48a00b /clang/lib/CodeGen/CodeGenModule.cpp | |
| parent | 1257fe193a35b3b3ee8ccc5987f376b0b6dc21ea (diff) | |
[clang] Allow const variables with weak attribute to be overridden
A variable with `weak` attribute signifies that it can be replaced with
a "strong" symbol link time. Therefore it must not emitted with
"weak_odr" linkage, as that allows the backend to use its value in
optimizations.
The frontend already considers weak const variables as
non-constant (note_constexpr_var_init_weak diagnostic) so this change
makes frontend and backend consistent.
This commit reverses the
f49573d1 weak globals that are const should get weak_odr linkage.
commit from 2009-08-05 which introduced this behavior. Unfortunately
that commit doesn't provide any details on why the change was made.
This was discussed in
https://discourse.llvm.org/t/weak-attribute-semantics-on-const-variables/62311
Differential Revision: https://reviews.llvm.org/D126324
Diffstat (limited to 'clang/lib/CodeGen/CodeGenModule.cpp')
| -rw-r--r-- | clang/lib/CodeGen/CodeGenModule.cpp | 8 |
1 files changed, 2 insertions, 6 deletions
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp index b4ae266f8988..758887a3b627 100644 --- a/clang/lib/CodeGen/CodeGenModule.cpp +++ b/clang/lib/CodeGen/CodeGenModule.cpp @@ -4899,12 +4899,8 @@ llvm::GlobalValue::LinkageTypes CodeGenModule::getLLVMLinkageForDeclarator( if (Linkage == GVA_Internal) return llvm::Function::InternalLinkage; - if (D->hasAttr<WeakAttr>()) { - if (IsConstantVariable) - return llvm::GlobalVariable::WeakODRLinkage; - else - return llvm::GlobalVariable::WeakAnyLinkage; - } + if (D->hasAttr<WeakAttr>()) + return llvm::GlobalVariable::WeakAnyLinkage; if (const auto *FD = D->getAsFunction()) if (FD->isMultiVersion() && Linkage == GVA_AvailableExternally) |