[PATCH] D156897: [CodeGen] Clean up access to EmittedDeferredDecls, NFCI.

[Jonas Hahnfeld via Phabricator via cfe-commits]

Hahnfeld created this revision.
Hahnfeld added reviewers: rjmccall, v.g.vassilev, junaire.
Herald added a project: All.
Hahnfeld requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

`GlobalDecl`s should only be added to `EmittedDeferredDecl` if they
need reemission. This is checked in `addEmittedDeferredDecl`, which
is called via `addDeferredDeclToEmit`. Extend these checks to also
handle `VarDecls` (for lambdas, as tested in `Interpreter/lambda.cpp`)
and remove the direct access of `EmittedDeferredDecls` in `EmitGlobal`
that may actually end up duplicating `FunctionDecl`s.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D156897

Files:
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/CodeGen/CodeGenModule.h


Index: clang/lib/CodeGen/CodeGenModule.h
===================================================================
--- clang/lib/CodeGen/CodeGenModule.h
+++ clang/lib/CodeGen/CodeGenModule.h
@@ -361,10 +361,15 @@
   llvm::DenseMap<llvm::StringRef, GlobalDecl> EmittedDeferredDecls;
 
   void addEmittedDeferredDecl(GlobalDecl GD) {
-    if (!llvm::isa<FunctionDecl>(GD.getDecl()))
-      return;
-    llvm::GlobalVariable::LinkageTypes L = getFunctionLinkage(GD);
-    if (llvm::GlobalValue::isLinkOnceLinkage(L) ||
+    // Assume a linkage by default that does not need reemission.
+    auto L = llvm::GlobalValue::ExternalLinkage;
+    if (llvm::isa<FunctionDecl>(GD.getDecl()))
+      L = getFunctionLinkage(GD);
+    else if (auto *VD = llvm::dyn_cast<VarDecl>(GD.getDecl()))
+      L = getLLVMLinkageVarDefinition(VD);
+
+    if (llvm::GlobalValue::isInternalLinkage(L) ||
+        llvm::GlobalValue::isLinkOnceLinkage(L) ||
         llvm::GlobalValue::isWeakLinkage(L)) {
       EmittedDeferredDecls[getMangledName(GD)] = GD;
     }
Index: clang/lib/CodeGen/CodeGenModule.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenModule.cpp
+++ clang/lib/CodeGen/CodeGenModule.cpp
@@ -3664,7 +3664,6 @@
     // The value must be emitted, but cannot be emitted eagerly.
     assert(!MayBeEmittedEagerly(Global));
     addDeferredDeclToEmit(GD);
-    EmittedDeferredDecls[MangledName] = GD;
   } else {
     // Otherwise, remember that we saw a deferred decl with this name.  The
     // first use of the mangled name will cause it to move into
@@ -4404,7 +4403,6 @@
       // DeferredDeclsToEmit list, and remove it from DeferredDecls (since we
       // don't need it anymore).
       addDeferredDeclToEmit(DDI->second);
-      EmittedDeferredDecls[DDI->first] = DDI->second;
       DeferredDecls.erase(DDI);
 
       // Otherwise, there are cases we have to worry about where we're
@@ -4685,7 +4683,6 @@
     // Move the potentially referenced deferred decl to the DeferredDeclsToEmit
     // list, and remove it from DeferredDecls (since we don't need it anymore).
     addDeferredDeclToEmit(DDI->second);
-    EmittedDeferredDecls[DDI->first] = DDI->second;
     DeferredDecls.erase(DDI);
   }
 


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