Update llvm/clang to trunk r126547.

There are several bugfixes in this update, but the most important one is
to ensure __start_ and __stop_ symbols for linker sets and kernel module
metadata are always emitted in object files:

  http://llvm.org/bugs/show_bug.cgi?id=9292

Before this fix, if you compiled kernel modules with clang, they would
not be properly processed by kldxref, and if they had any dependencies,
the kernel would fail to load those.  Another problem occurred when
attempting to mount a tmpfs filesystem, which would result in 'operation
not supported by device'.

1 files changed, 49 insertions, 1 deletions

diff --git a/contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.h b/contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.h
index 67ef414..be646fb 100644
--- a/contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.h
+++ b/contrib/llvm/tools/clang/lib/CodeGen/CodeGenFunction.h
@@ -1555,7 +1555,55 @@ public:
   /// EmitAutoVarDecl - Emit an auto variable declaration.
   ///
   /// This function can be called with a null (unreachable) insert point.
-  void EmitAutoVarDecl(const VarDecl &D, SpecialInitFn *SpecialInit = 0);
+  void EmitAutoVarDecl(const VarDecl &D);
+
+  class AutoVarEmission {
+    friend class CodeGenFunction;
+
+    const VarDecl *Variable;
+
+    /// The alignment of the variable.
+    CharUnits Alignment;
+
+    /// The address of the alloca.  Null if the variable was emitted
+    /// as a global constant.
+    llvm::Value *Address;
+
+    llvm::Value *NRVOFlag;
+
+    /// True if the variable is a __block variable.
+    bool IsByRef;
+
+    /// True if the variable is of aggregate type and has a constant
+    /// initializer.
+    bool IsConstantAggregate;
+
+    struct Invalid {};
+    AutoVarEmission(Invalid) : Variable(0) {}
+
+    AutoVarEmission(const VarDecl &variable)
+      : Variable(&variable), Address(0), NRVOFlag(0),
+        IsByRef(false), IsConstantAggregate(false) {}
+
+    bool wasEmittedAsGlobal() const { return Address == 0; }
+
+  public:
+    static AutoVarEmission invalid() { return AutoVarEmission(Invalid()); }
+
+    /// Returns the address of the object within this declaration.
+    /// Note that this does not chase the forwarding pointer for
+    /// __block decls.
+    llvm::Value *getObjectAddress(CodeGenFunction &CGF) const {
+      if (!IsByRef) return Address;
+
+      return CGF.Builder.CreateStructGEP(Address,
+                                         CGF.getByRefValueLLVMField(Variable),
+                                         Variable->getNameAsString());
+    }
+  };
+  AutoVarEmission EmitAutoVarAlloca(const VarDecl &var);
+  void EmitAutoVarInit(const AutoVarEmission &emission);
+  void EmitAutoVarCleanups(const AutoVarEmission &emission);  
 
   void EmitStaticVarDecl(const VarDecl &D,
                          llvm::GlobalValue::LinkageTypes Linkage);