[Clang][P1061] Add stuctured binding packs (#121417)

This is an implementation of P1061 Structure Bindings Introduce a Pack
without the ability to use packs outside of templates. There is a couple
of ways the AST could have been sliced so let me know what you think.
The only part of this change that I am unsure of is the
serialization/deserialization stuff. I followed the implementation of
other Exprs, but I do not really know how it is tested. Thank you for
your time considering this.

---------

Co-authored-by: Yanzuo Liu <zwuis@outlook.com>

3 files changed, 5 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index f0abfaa..db59579 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -5083,10 +5083,9 @@ CGDebugInfo::EmitDeclareOfAutoVariable(const VarDecl *VD, llvm::Value *Storage,
   assert(CGM.getCodeGenOpts().hasReducedDebugInfo());
 
   if (auto *DD = dyn_cast<DecompositionDecl>(VD)) {
-    for (auto *B : DD->bindings()) {
+    for (BindingDecl *B : DD->flat_bindings())
       EmitDeclare(B, Storage, std::nullopt, Builder,
                   VD->getType()->isReferenceType());
-    }
     // Don't emit an llvm.dbg.declare for the composite storage as it doesn't
     // correspond to a user variable.
     return nullptr;
diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 747e420d..cc6815d 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -164,9 +164,10 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
            "Should not see file-scope variables inside a function!");
     EmitVarDecl(VD);
     if (auto *DD = dyn_cast<DecompositionDecl>(&VD))
-      for (auto *B : DD->bindings())
+      for (auto *B : DD->flat_bindings())
         if (auto *HD = B->getHoldingVar())
           EmitVarDecl(*HD);
+
     return;
   }
 
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index eb8d3ce..a015d64 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -7014,9 +7014,10 @@ void CodeGenModule::EmitTopLevelDecl(Decl *D) {
   case Decl::VarTemplateSpecialization:
     EmitGlobal(cast<VarDecl>(D));
     if (auto *DD = dyn_cast<DecompositionDecl>(D))
-      for (auto *B : DD->bindings())
+      for (auto *B : DD->flat_bindings())
         if (auto *HD = B->getHoldingVar())
           EmitGlobal(HD);
+
     break;
 
   // Indirect fields from global anonymous structs and unions can be