P0217R3: code generation support for decomposition declarations.

llvm-svn: 278642

3 files changed, 17 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index e0cb07b98dd..037b1351c0f 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -87,6 +87,7 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
   case Decl::UsingShadow:
   case Decl::ConstructorUsingShadow:
   case Decl::ObjCTypeParam:
+  case Decl::Binding:
     llvm_unreachable("Declaration should not be in declstmts!");
   case Decl::Function:  // void X();
   case Decl::Record:    // struct/union/class X;
@@ -119,10 +120,13 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
     const VarDecl &VD = cast<VarDecl>(D);
     assert(VD.isLocalVarDecl() &&
            "Should not see file-scope variables inside a function!");
-    return EmitVarDecl(VD);
+    EmitVarDecl(VD);
+    if (auto *DD = dyn_cast<DecompositionDecl>(&VD))
+      for (auto *B : DD->bindings())
+        if (auto *HD = B->getHoldingVar())
+          EmitVarDecl(*HD);
+    return;
   }
-  case Decl::Binding:
-    return CGM.ErrorUnsupported(&D, "structured binding");
 
   case Decl::OMPDeclareReduction:
     return CGM.EmitOMPDeclareReduction(cast<OMPDeclareReductionDecl>(&D), this);
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index 039936a3a64..89df63d8bf3 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -2206,6 +2206,12 @@ LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
   if (const auto *FD = dyn_cast<FunctionDecl>(ND))
     return EmitFunctionDeclLValue(*this, E, FD);
 
+  // FIXME: While we're emitting a binding from an enclosing scope, all other
+  // DeclRefExprs we see should be implicitly treated as if they also refer to
+  // an enclosing scope.
+  if (const auto *BD = dyn_cast<BindingDecl>(ND))
+    return EmitLValue(BD->getBinding());
+
   llvm_unreachable("Unhandled DeclRefExpr");
 }
 
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 888af29d403..f20baab784b 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3772,6 +3772,10 @@ void CodeGenModule::EmitTopLevelDecl(Decl *D) {
       return;
   case Decl::VarTemplateSpecialization:
     EmitGlobal(cast<VarDecl>(D));
+    if (auto *DD = dyn_cast<DecompositionDecl>(D))
+      for (auto *B : DD->bindings())
+        if (auto *HD = B->getHoldingVar())
+          EmitGlobal(HD);
     break;
 
   // Indirect fields from global anonymous structs and unions can be