[PATCH] D100606: [lld-link] Warn on exported deleting dtor

[Zequan Wu via Phabricator via llvm-commits]

zequanwu created this revision.
zequanwu added a reviewer: rnk.
zequanwu requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

MSVC linker has this warning <https://docs.microsoft.com/en-us/cpp/error-messages/tool-errors/linker-tools-warning-lnk4102?view=msvc-160>, so lld-link should also warn on this.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D100606

Files:
  lld/COFF/Writer.cpp
  lld/test/COFF/export-deleting-dtor.s


Index: lld/test/COFF/export-deleting-dtor.s
===================================================================
--- /dev/null
+++ lld/test/COFF/export-deleting-dtor.s
@@ -0,0 +1,26 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -triple=x86_64-windows-msvc -defsym drectve=0 %s -filetype=obj -o %t.obj
+# RUN: echo -e "EXPORTS\n  ??_G?\$Foo at H@@UEAAPEAXI at Z" > %t.def
+
+# RUN: lld-link %t.obj -entry:dllmain -dll -export:'??_G?$Foo at H@@UEAAPEAXI at Z' -out:%t.1.dll 2>&1 | FileCheck %s
+
+# RUN: lld-link %t.obj -entry:dllmain -dll -def:%t.def -out:%t.2.dll 2>&1 | FileCheck %s
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-windows-msvc -defsym drectve=1 %s -o %t.drectve.obj
+# RUN: lld-link %t.drectve.obj -entry:dllmain -dll -out:%t.3.dll 2>&1 | FileCheck %s
+
+# CHECK: export of deleting destructor: 
+
+        .text
+        .globl  dllmain
+        .globl  "??_G?$Foo at H@@UEAAPEAXI at Z"
+dllmain:
+        ret
+"??_G?$Foo at H@@UEAAPEAXI at Z":
+        ret
+
+.if drectve==1
+        .section .drectve
+        .ascii "-export:??_G?$Foo at H@@UEAAPEAXI at Z"
+.endif
Index: lld/COFF/Writer.cpp
===================================================================
--- lld/COFF/Writer.cpp
+++ lld/COFF/Writer.cpp
@@ -1078,6 +1078,10 @@
     edataStart = edataSec->chunks.front();
     edataEnd = edataSec->chunks.back();
   }
+  // Warn on exported deleting destructor.
+  for (auto e : config->exports)
+    if (e.sym->getName().startswith("??_G"))
+      warn("export of deleting dtor: " + toString(*e.sym));
 }
 
 void Writer::removeUnusedSections() {


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