slavapestov added a subscriber: slavapestov.
slavapestov added a comment.
Unfortunately the asm label attribute doesn’t seem to work in this case, at
least on Darwin. I get two symbols in the IR, with the asm label having the \01
prefix from MangleContext::mangleName():
@"\01OBJC_CLASS_$_NSNumber" = common global %struct.art_class* null, align 8
@"OBJC_CLASS_$_NSNumber" = external global %struct._class_t
As for the diagnostic, is this what you had in mind?
commit 4d4f15ffc4d6a72357fa4cee8e2197a03afe6b51
Author: Slava Pestov <spes...@apple.com>
Date: Fri Oct 23 23:57:56 2015 -0700
CodeGen: More robust handling of type conflicts in GetClassGlobal()
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index 31e98b9..e5ef767 100644
- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -6692,16 +6692,31 @@ CGObjCNonFragileABIMac::GetClassGlobal(const
std::string &Name,
llvm::GlobalVariable *GV = CGM.getModule().getGlobalVariable(Name);
- if (!GV)
- GV = new llvm::GlobalVariable(CGM.getModule(), ObjCTypes.ClassnfABITy,
- false, L, nullptr, Name);
+ // If it doesn't exist, create it with the right type.
+ if (!GV) {
+ return new llvm::GlobalVariable(CGM.getModule(), ObjCTypes.ClassnfABITy,
+ false, L, nullptr, Name);
+ }
assert(GV->getLinkage() == L);
- if (ForDefinition ||
- GV->getValueType() == ObjCTypes.ClassnfABITy)
+ // If it already exists, we might need to bitcast.
+ if (GV->getValueType() == ObjCTypes.ClassnfABITy)
return GV;
+ if (ForDefinition) {
+ DiagnosticsEngine &Diags = CGM.getDiags();
+ unsigned DiagID = Diags.getCustomDiagID(
+ DiagnosticsEngine::Error,
+ "global variable %0 already defined with wrong type");
+ Diags.Report(SourceLocation(), DiagID) << Name;
+
+ // Return a new global in this case, with the right type, since the caller
+ // doesn't expect a constexpr
+ return new llvm::GlobalVariable(CGM.getModule(), ObjCTypes.ClassnfABITy,
+ false, L, nullptr, Name);
+ }
+
return llvm::ConstantExpr::getBitCast(GV, ObjCTypes.ClassnfABIPtrTy);
}
Repository:
rL LLVM
http://reviews.llvm.org/D13954
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