[PATCH] D37009: [ELF] - Fix for "Bug 34238 - LTO is optimizing away symbols referenced from linker scripts"

[George Rimar via Phabricator via llvm-commits]

grimar updated this revision to Diff 112194.
grimar added a comment.

- Restored original comment.


https://reviews.llvm.org/D37009

Files:
  ELF/Driver.cpp
  test/ELF/lto/linker-script-symbols.ll


Index: test/ELF/lto/linker-script-symbols.ll
===================================================================
--- test/ELF/lto/linker-script-symbols.ll
+++ test/ELF/lto/linker-script-symbols.ll
@@ -0,0 +1,29 @@
+; REQUIRES: x86
+; RUN: llvm-as %s -o %t.o
+; RUN: echo "foo = bar;" > %t.script
+
+; RUN: ld.lld -m elf_x86_64 %t.o -o %t2 --script %t.script -save-temps
+; RUN: llvm-readobj -symbols %t2.lto.o | FileCheck %s
+
+; CHECK-NOT:  zed
+; CHECK:      Symbol {
+; CHECK:        Name: bar
+; CHECK-NEXT:   Value:
+; CHECK-NEXT:   Size:
+; CHECK-NEXT:   Binding: Global
+; CHECK-NEXT:   Type: Function
+; CHECK-NEXT:   Other:
+; CHECK-NEXT:   Section:
+; CHECK-NEXT: }
+; CHECK-NOT:  zed
+
+target triple = "x86_64-unknown-linux-gnu"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @bar() {
+  ret void
+}
+
+define void @zed() {
+  ret void
+}
Index: ELF/Driver.cpp
===================================================================
--- ELF/Driver.cpp
+++ ELF/Driver.cpp
@@ -1012,6 +1012,11 @@
   for (InputFile *F : Files)
     Symtab->addFile<ELFT>(F);
 
+  // Some symbols (such as __ehdr_start) are defined lazily only when there
+  // are undefined symbols for them, so we add these to trigger that logic.
+  for (StringRef Sym : Script->Opt.ReferencedSymbols)
+    Symtab->addUndefined<ELFT>(Sym);
+
   // If an entry symbol is in a static archive, pull out that file now
   // to complete the symbol table. After this, no new names except a
   // few linker-synthesized ones will be added to the symbol table.
@@ -1047,11 +1052,6 @@
   if (ErrorCount)
     return;
 
-  // Some symbols (such as __ehdr_start) are defined lazily only when there
-  // are undefined symbols for them, so we add these to trigger that logic.
-  for (StringRef Sym : Script->Opt.ReferencedSymbols)
-    Symtab->addUndefined<ELFT>(Sym);
-
   // Apply symbol renames for -wrap and -defsym
   Symtab->applySymbolRenames();
 


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