ELFObjectWriter: Allow one unique symver per symbol

Summary:
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

Reviewers: pcc, tejohnson, espindola

Reviewed By: pcc

Subscribers: emaste, arichardson, llvm-commits, kcc

Differential Revision: https://reviews.llvm.org/D45845

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331078 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index 989d4bb..85bbcab 100644 (file)
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -420,6 +420,10 @@ void ELFObjectWriter::executePostLayoutBinding(MCAssembler &Asm,
         !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));
   }
 }

diff --git a/test/MC/ELF/multiple-different-symver.s b/test/MC/ELF/multiple-different-symver.s
new file mode 100644 (file)
index 0000000..d7706f8
--- /dev/null
+++ b/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@1
+.symver foo, foo@2

diff --git a/test/MC/ELF/multiple-equiv-symver.s b/test/MC/ELF/multiple-equiv-symver.s
new file mode 100644 (file)
index 0000000..0ab48f0
--- /dev/null
+++ b/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@1
+.symver foo, foo@1