weak globals that are const should get weak_odr linkage.
add a fixme about C++ const.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@78159 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 95ce3e5..df1781d 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -870,7 +870,15 @@
}
GV->setInitializer(Init);
- GV->setConstant(D->getType().isConstant(Context));
+
+ // If it is safe to mark the global 'constant', do so now.
+ GV->setConstant(false);
+ if (D->getType().isConstant(Context)) {
+ // FIXME: In C++, if the variable has a non-trivial ctor/dtor or any mutable
+ // members, it cannot be declared "LLVM const".
+ GV->setConstant(true);
+ }
+
GV->setAlignment(getContext().getDeclAlignInBytes(D));
// Set the llvm linkage type as appropriate.
@@ -880,13 +888,18 @@
GV->setLinkage(llvm::Function::DLLImportLinkage);
else if (D->hasAttr<DLLExportAttr>())
GV->setLinkage(llvm::Function::DLLExportLinkage);
- else if (D->hasAttr<WeakAttr>())
- GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
- else if (!CompileOpts.NoCommon &&
+ else if (D->hasAttr<WeakAttr>()) {
+ if (GV->isConstant())
+ GV->setLinkage(llvm::GlobalVariable::WeakODRLinkage);
+ else
+ GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
+ } else if (!CompileOpts.NoCommon &&
!D->hasExternalStorage() && !D->getInit() &&
- !D->getAttr<SectionAttr>())
+ !D->getAttr<SectionAttr>()) {
GV->setLinkage(llvm::GlobalVariable::CommonLinkage);
- else
+ // common vars aren't constant even if declared const.
+ GV->setConstant(false);
+ } else
GV->setLinkage(llvm::GlobalVariable::ExternalLinkage);
SetCommonAttributes(D, GV);
diff --git a/test/CodeGen/global-init.c b/test/CodeGen/global-init.c
index 2c4ccce..2a4c77b 100644
--- a/test/CodeGen/global-init.c
+++ b/test/CodeGen/global-init.c
@@ -7,8 +7,24 @@
int a = 242;
// CHECK: @a = global i32 242
+// This should get normal weak linkage.
+int c __attribute__((weak))= 0;
+// CHECK: @c = weak global i32 0
+
+
+
+// Since this is marked const, it should get weak_odr linkage, since all
+// definitions have to be the same.
+// CHECK: @d = weak_odr constant i32 0
+const int d __attribute__((weak))= 0;
+
+
+
+// NOTE: tentative definitions are processed at the end of the translation unit.
+
// This shouldn't be emitted as common because it has an explicit section.
// rdar://7119244
int b __attribute__((section("foo")));
// CHECK: @b = global i32 0, section "foo"
+