[PATCH] D45845: ELFObjectWriter: Allow one unique symver per symbol

[Vlad Tsyrklevich via Phabricator via llvm-commits]

vlad.tsyrklevich created this revision.
vlad.tsyrklevich added reviewers: pcc, tejohnson.
Herald added subscribers: llvm-commits, arichardson, emaste.
Herald added a reviewer: espindola.

Only allow a single unique .symver alias per symbol. This matches the
behavior of gas. I noticed that we ignored multiple mismatched symver
directives looking at https://reviews.llvm.org/D45798


Repository:
  rL LLVM

https://reviews.llvm.org/D45845

Files:
  lib/MC/ELFObjectWriter.cpp
  test/MC/ELF/multiple-different-symver.s
  test/MC/ELF/multiple-equiv-symver.s


Index: test/MC/ELF/multiple-equiv-symver.s
===================================================================
--- /dev/null
+++ test/MC/ELF/multiple-equiv-symver.s
@@ -0,0 +1,6 @@
+// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - 2>&1 | FileCheck %s
+
+// CHECK-NOT: Multiple symbol versions defined for foo
+
+.symver foo, foo at 1
+.symver foo, foo at 1
Index: test/MC/ELF/multiple-different-symver.s
===================================================================
--- /dev/null
+++ test/MC/ELF/multiple-different-symver.s
@@ -0,0 +1,6 @@
+// RUN: not llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o %t 2>&1 | FileCheck %s
+
+// CHECK: Multiple symbol versions defined for foo
+
+.symver foo, foo at 1
+.symver foo, foo at 2
Index: lib/MC/ELFObjectWriter.cpp
===================================================================
--- lib/MC/ELFObjectWriter.cpp
+++ lib/MC/ELFObjectWriter.cpp
@@ -420,6 +420,10 @@
         !Rest.startswith("@@@"))
       report_fatal_error("A @@ version cannot be undefined");
 
+    if (Renames.count(&Symbol) && Renames[&Symbol] != Alias)
+      report_fatal_error(llvm::Twine("Multiple symbol versions defined for ") +
+                         Symbol.getName());
+
     Renames.insert(std::make_pair(&Symbol, Alias));
   }
 }


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