[clang] b719e41 - [CodeGen] Clean up access to EmittedDeferredDecls, NFCI.

[Jonas Hahnfeld via cfe-commits]

Author: Jonas Hahnfeld
Date: 2023-08-17T10:39:47+02:00
New Revision: b719e410781ce9f3a2b316afea31c156bf99e036

URL: https://github.com/llvm/llvm-project/commit/b719e410781ce9f3a2b316afea31c156bf99e036
DIFF: https://github.com/llvm/llvm-project/commit/b719e410781ce9f3a2b316afea31c156bf99e036.diff

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

GlobalDecls should only be added to EmittedDeferredDecls 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 FunctionDecls.

Differential Revision: https://reviews.llvm.org/D156897

Added: 
    

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

Removed: 
    


################################################################################
diff  --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 2a7a36e53d8189..517af514d9c998 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -3677,7 +3677,6 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
     // 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
@@ -4417,7 +4416,6 @@ llvm::Constant *CodeGenModule::GetOrCreateLLVMFunction(
       // 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
@@ -4677,7 +4675,6 @@ CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName, llvm::Type *Ty,
     // 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);
   }
 

diff  --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index ef90eaca59a4e0..7301109fb04409 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -361,10 +361,15 @@ class CodeGenModule : public CodeGenTypeCache {
   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;
     }