r285073 - CodeGen: mark protocols as common data

[Saleem Abdulrasool via cfe-commits]

Author: compnerd
Date: Tue Oct 25 09:50:44 2016
New Revision: 285073

URL: http://llvm.org/viewvc/llvm-project?rev=285073&view=rev
Log:
CodeGen: mark protocols as common data

This allows for the coalescing of the protocol declarations.  When the protocols
are declared in headers, multiple definitions of the protocol would be emitted.
Marking them as common data indicates that any one can be selected.

Added:
    cfe/trunk/test/CodeGenObjC/protocol-comdat.m
Modified:
    cfe/trunk/lib/CodeGen/CGObjCMac.cpp

Modified: cfe/trunk/lib/CodeGen/CGObjCMac.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGObjCMac.cpp?rev=285073&r1=285072&r2=285073&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGObjCMac.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGObjCMac.cpp Tue Oct 25 09:50:44 2016
@@ -6562,15 +6562,20 @@ llvm::Constant *CGObjCNonFragileABIMac::
   const ObjCProtocolDecl *PD) {
   llvm::GlobalVariable *&Entry = Protocols[PD->getIdentifier()];
 
-  if (!Entry)
+  if (!Entry) {
     // We use the initializer as a marker of whether this is a forward
     // reference or not. At module finalization we add the empty
     // contents for protocols which were referenced but never defined.
-    Entry =
-        new llvm::GlobalVariable(CGM.getModule(), ObjCTypes.ProtocolnfABITy,
-                                 false, llvm::GlobalValue::ExternalLinkage,
-                                 nullptr,
-                                 "\01l_OBJC_PROTOCOL_$_" + PD->getObjCRuntimeNameAsString());
+    llvm::SmallString<64> Protocol;
+    llvm::raw_svector_ostream(Protocol) << "\01l_OBJC_PROTOCOL_$_"
+                                        << PD->getObjCRuntimeNameAsString();
+
+    Entry = new llvm::GlobalVariable(CGM.getModule(), ObjCTypes.ProtocolnfABITy,
+                                     false, llvm::GlobalValue::ExternalLinkage,
+                                     nullptr, Protocol);
+    if (!CGM.getTriple().isOSBinFormatMachO())
+      Entry->setComdat(CGM.getModule().getOrInsertComdat(Protocol));
+  }
 
   return Entry;
 }
@@ -6688,10 +6693,16 @@ llvm::Constant *CGObjCNonFragileABIMac::
     Entry->setLinkage(llvm::GlobalValue::WeakAnyLinkage);
     Entry->setInitializer(Init);
   } else {
-    Entry =
-      new llvm::GlobalVariable(CGM.getModule(), ObjCTypes.ProtocolnfABITy,
-                               false, llvm::GlobalValue::WeakAnyLinkage, Init,
-                               "\01l_OBJC_PROTOCOL_$_" + PD->getObjCRuntimeNameAsString());
+    llvm::SmallString<64> Protocol;
+    llvm::raw_svector_ostream(Protocol) << "\01l_OBJC_PROTOCOL_$_"
+                                        << PD->getObjCRuntimeNameAsString();
+
+    Entry = new llvm::GlobalVariable(CGM.getModule(), ObjCTypes.ProtocolnfABITy,
+                                     false, llvm::GlobalValue::WeakAnyLinkage,
+                                     Init, Protocol);
+    if (!CGM.getTriple().isOSBinFormatMachO())
+      Entry->setComdat(CGM.getModule().getOrInsertComdat(Protocol));
+
     Entry->setAlignment(
       CGM.getDataLayout().getABITypeAlignment(ObjCTypes.ProtocolnfABITy));
 
@@ -6702,13 +6713,20 @@ llvm::Constant *CGObjCNonFragileABIMac::
 
   // Use this protocol meta-data to build protocol list table in section
   // __DATA, __objc_protolist
+  llvm::SmallString<64> ProtocolRef;
+  llvm::raw_svector_ostream(ProtocolRef) << "\01l_OBJC_LABEL_PROTOCOL_$_"
+                                         << PD->getObjCRuntimeNameAsString();
+
   llvm::GlobalVariable *PTGV =
     new llvm::GlobalVariable(CGM.getModule(), ObjCTypes.ProtocolnfABIPtrTy,
                              false, llvm::GlobalValue::WeakAnyLinkage, Entry,
-                             "\01l_OBJC_LABEL_PROTOCOL_$_" + PD->getObjCRuntimeNameAsString());
+                             ProtocolRef);
+  if (!CGM.getTriple().isOSBinFormatMachO())
+    PTGV->setComdat(CGM.getModule().getOrInsertComdat(ProtocolRef));
   PTGV->setAlignment(
     CGM.getDataLayout().getABITypeAlignment(ObjCTypes.ProtocolnfABIPtrTy));
-  PTGV->setSection("__DATA, __objc_protolist, coalesced, no_dead_strip");
+  if (CGM.getTriple().isOSBinFormatMachO())
+    PTGV->setSection("__DATA, __objc_protolist, coalesced, no_dead_strip");
   PTGV->setVisibility(llvm::GlobalValue::HiddenVisibility);
   CGM.addCompilerUsedGlobal(PTGV);
   return Entry;

Added: cfe/trunk/test/CodeGenObjC/protocol-comdat.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenObjC/protocol-comdat.m?rev=285073&view=auto
==============================================================================
--- cfe/trunk/test/CodeGenObjC/protocol-comdat.m (added)
+++ cfe/trunk/test/CodeGenObjC/protocol-comdat.m Tue Oct 25 09:50:44 2016
@@ -0,0 +1,20 @@
+// RUN: %clang -cc1 -triple thumbv7--windows-itanium -fobjc-runtime=ios -emit-llvm -o - %s -Wno-objc-root-class | FileCheck %s
+
+ at protocol P
+- (void) method;
+ at end
+
+ at interface I<P>
+ at end
+
+ at implementation I
+- (void) method { }
+ at end
+
+
+// CHECK: $"\01l_OBJC_PROTOCOL_$_P" = comdat any
+// CHECK: $"\01l_OBJC_LABEL_PROTOCOL_$_P" = comdat any
+
+// CHECK: @"\01l_OBJC_PROTOCOL_$_P" = {{.*}}, comdat
+// CHECK: @"\01l_OBJC_LABEL_PROTOCOL_$_P" = {{.*}}, comdat
+