fix some cfstring related issues:

1) -fwritable-string does affect the non-utf16 version of cfstrings
   just not the utf16 ones.
2) utf16 strings should always be marked constant, as the __TEXT segment
   is readonly.
3) The name of the global doesn't matter, remove it from TargetInfo.
4) Trust the asmprinter to drop cstrings into the right section, like llvmgcc does now.

This fixes rdar://7115750

llvm-svn: 84077

1 files changed, 10 insertions, 13 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 4c8ef583677..a7658e5e14f 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1434,27 +1434,24 @@ CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) {
   // String pointer.
   llvm::Constant *C = llvm::ConstantArray::get(VMContext, Entry.getKey().str());
 
-  const char *Sect, *Prefix;
-  bool isConstant;
+  const char *Sect = 0;
   llvm::GlobalValue::LinkageTypes Linkage;
+  bool isConstant;
   if (isUTF16) {
-    Prefix = getContext().Target.getUnicodeStringSymbolPrefix();
     Sect = getContext().Target.getUnicodeStringSection();
-    // FIXME: why do utf strings get "l" labels instead of "L" labels?
+    // FIXME: why do utf strings get "_" labels instead of "L" labels?
     Linkage = llvm::GlobalValue::InternalLinkage;
-    // FIXME: Why does GCC not set constant here?
-    isConstant = false;
+    // Note: -fwritable-strings doesn't make unicode CFStrings writable, but
+    // does make plain ascii ones writable.
+    isConstant = true;
   } else {
-    Prefix = ".str";
-    Sect = getContext().Target.getCFStringDataSection();
     Linkage = llvm::GlobalValue::PrivateLinkage;
-    // FIXME: -fwritable-strings should probably affect this, but we
-    // are following gcc here.
-    isConstant = true;
+    isConstant = !Features.WritableStrings;
   }
+  
   llvm::GlobalVariable *GV =
-    new llvm::GlobalVariable(getModule(), C->getType(), isConstant,
-                             Linkage, C, Prefix);
+    new llvm::GlobalVariable(getModule(), C->getType(), isConstant, Linkage, C,
+                             ".str");
   if (Sect)
     GV->setSection(Sect);
   if (isUTF16) {