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, 26 insertions, 3 deletions

diff --git a/contrib/llvm/tools/clang/lib/Sema/Sema.cpp b/contrib/llvm/tools/clang/lib/Sema/Sema.cpp
index 23a3c24..0c39e13 100644
--- a/contrib/llvm/tools/clang/lib/Sema/Sema.cpp
+++ b/contrib/llvm/tools/clang/lib/Sema/Sema.cpp
@@ -48,6 +48,7 @@ void FunctionScopeInfo::Clear() {
   SwitchStack.clear();
   Returns.clear();
   ErrorTrap.reset();
+  PossiblyUnreachableDiags.clear();
 }
 
 BlockScopeInfo::~BlockScopeInfo() { }
@@ -466,6 +467,12 @@ void Sema::ActOnEndOfTranslationUnit() {
     checkUndefinedInternals(*this);
   }
 
+  // Check we've noticed that we're no longer parsing the initializer for every
+  // variable. If we miss cases, then at best we have a performance issue and
+  // at worst a rejects-valid bug.
+  assert(ParsingInitForAutoVars.empty() &&
+         "Didn't unmark var as having its initializer parsed");
+
   TUScope = 0;
 }
 
@@ -625,11 +632,27 @@ void Sema::PushBlockScope(Scope *BlockScope, BlockDecl *Block) {
                                               BlockScope, Block));
 }
 
-void Sema::PopFunctionOrBlockScope() {
-  FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();
+void Sema::PopFunctionOrBlockScope(const AnalysisBasedWarnings::Policy *WP,
+                                   const Decl *D, const BlockExpr *blkExpr) {
+  FunctionScopeInfo *Scope = FunctionScopes.pop_back_val();  
   assert(!FunctionScopes.empty() && "mismatched push/pop!");
-  if (FunctionScopes.back() != Scope)
+  
+  // Issue any analysis-based warnings.
+  if (WP && D)
+    AnalysisWarnings.IssueWarnings(*WP, Scope, D, blkExpr);
+  else {
+    for (llvm::SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
+         i = Scope->PossiblyUnreachableDiags.begin(),
+         e = Scope->PossiblyUnreachableDiags.end();
+         i != e; ++i) {
+      const sema::PossiblyUnreachableDiag &D = *i;
+      Diag(D.Loc, D.PD);
+    }
+  }
+
+  if (FunctionScopes.back() != Scope) {
     delete Scope;
+  }
 }
 
 /// \brief Determine whether any errors occurred within this function/method/