[PATCH] D99732: [AST] Pick last tentative definition as the acting definition

[Benson Chu via Phabricator via cfe-commits]

pestctrl updated this revision to Diff 335113.
pestctrl edited the summary of this revision.
pestctrl added a comment.

Removed extra pass over decl chain for acting definition.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99732/new/

https://reviews.llvm.org/D99732

Files:
  clang/lib/AST/Decl.cpp
  clang/test/CodeGen/attr-tentative-definition.c


Index: clang/test/CodeGen/attr-tentative-definition.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/attr-tentative-definition.c
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -emit-llvm < %s | FileCheck %s
+
+char arr[10];
+char arr[10] __attribute__((section("datadata")));
+char arr[10] __attribute__((aligned(16)));
+
+// CHECK: @arr = dso_local global [10 x i8] zeroinitializer, section "datadata", align 16
Index: clang/lib/AST/Decl.cpp
===================================================================
--- clang/lib/AST/Decl.cpp
+++ clang/lib/AST/Decl.cpp
@@ -2193,14 +2193,18 @@
     return nullptr;
 
   VarDecl *LastTentative = nullptr;
-  VarDecl *First = getFirstDecl();
-  for (auto I : First->redecls()) {
-    Kind = I->isThisDeclarationADefinition();
+
+  // Loop through the declaration chain, starting with the most recent.
+  for (VarDecl *Decl = getMostRecentDecl(); Decl;
+       Decl = Decl->getPreviousDecl()) {
+    Kind = Decl->isThisDeclarationADefinition();
     if (Kind == Definition)
       return nullptr;
-    if (Kind == TentativeDefinition)
-      LastTentative = I;
+    // Record the first TentativeDefinition that is encountered.
+    if (Kind == TentativeDefinition && !LastTentative)
+      LastTentative = Decl;
   }
+
   return LastTentative;
 }
 


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