Revert rL362358 : PR42104: Support instantiations of lambdas that implicitly capture packs.

Two changes:
 * Track odr-use via FunctionParmPackExprs to properly handle dependent
   odr-uses of packs in generic lambdas.
 * Do not instantiate implicit captures; instead, regenerate them by
   instantiating the body of the lambda. This is necessary to
   distinguish between cases where only one element of a pack is
   captured and cases where the entire pack is captured.
........
Fixes http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win buildbot failures

llvm-svn: 362375

1 files changed, 14 insertions, 14 deletions

diff --git a/clang/lib/Sema/ScopeInfo.cpp b/clang/lib/Sema/ScopeInfo.cpp
index b2a26af9b4a..e84e592a482 100644
--- a/clang/lib/Sema/ScopeInfo.cpp
+++ b/clang/lib/Sema/ScopeInfo.cpp
@@ -229,20 +229,20 @@ bool CapturingScopeInfo::isVLATypeCaptured(const VariableArrayType *VAT) const {
   return false;
 }
 
-void LambdaScopeInfo::visitPotentialCaptures(
-    llvm::function_ref<void(VarDecl *, Expr *)> Callback) const {
-  for (Expr *E : PotentiallyCapturingExprs) {
-    if (auto *DRE = dyn_cast<DeclRefExpr>(E)) {
-      Callback(cast<VarDecl>(DRE->getFoundDecl()), E);
-    } else if (auto *ME = dyn_cast<MemberExpr>(E)) {
-      Callback(cast<VarDecl>(ME->getMemberDecl()), E);
-    } else if (auto *FP = dyn_cast<FunctionParmPackExpr>(E)) {
-      for (VarDecl *VD : *FP)
-        Callback(VD, E);
-    } else {
-      llvm_unreachable("unexpected expression in potential captures list");
-    }
-  }
+void LambdaScopeInfo::getPotentialVariableCapture(unsigned Idx, VarDecl *&VD,
+                                                  Expr *&E) const {
+  assert(Idx < getNumPotentialVariableCaptures() &&
+         "Index of potential capture must be within 0 to less than the "
+         "number of captures!");
+  E = PotentiallyCapturingExprs[Idx];
+  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
+    VD = dyn_cast<VarDecl>(DRE->getFoundDecl());
+  else if (MemberExpr *ME = dyn_cast<MemberExpr>(E))
+    VD = dyn_cast<VarDecl>(ME->getMemberDecl());
+  else
+    llvm_unreachable("Only DeclRefExprs or MemberExprs should be added for "
+    "potential captures");
+  assert(VD);
 }
 
 FunctionScopeInfo::~FunctionScopeInfo() { }