From 85815a31491561ba1ac9042c55d5312d2c98eb56 Mon Sep 17 00:00:00 2001
From: Simon Atanasyan <simon@atanasyan.com>
Date: Wed, 7 Feb 2018 10:02:49 +0000
Subject: [PATCH] [ELF][MIPS] Ignore incorrect version definition index for
 _gp_disp symbol

MIPS BFD linker puts _gp_disp symbol into DSO files and assigns zero
version definition index to it. This value means 'unversioned local
symbol' while _gp_disp is a section global symbol. We have to handle
this bug in the LLD because BFD linker is used for building MIPS
toolchain libraries.

Differential revision: https://reviews.llvm.org/D42486

llvm-svn: 324467
---
 lld/ELF/InputFiles.cpp                          |   8 ++++++++
 lld/test/ELF/Inputs/mips-gp-dips-corrupt-ver.s  |  14 ++++++++++++++
 lld/test/ELF/Inputs/mips-gp-dips-corrupt-ver.so | Bin 0 -> 2160 bytes
 lld/test/ELF/mips-gp-disp-ver.s                 |  13 +++++++++++++
 4 files changed, 35 insertions(+)
 create mode 100644 lld/test/ELF/Inputs/mips-gp-dips-corrupt-ver.s
 create mode 100755 lld/test/ELF/Inputs/mips-gp-dips-corrupt-ver.so
 create mode 100644 lld/test/ELF/mips-gp-disp-ver.s

diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
index 4edabc578667..457dc7dedf9f 100644
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -862,6 +862,14 @@ template <class ELFT> void SharedFile<ELFT>::parseRest() {
       continue;
     }
 
+    if (Config->EMachine == EM_MIPS) {
+      // FIXME: MIPS BFD linker puts _gp_disp symbol into DSO files
+      // and incorrectly assigns VER_NDX_LOCAL to this section global
+      // symbol. Here is a workaround for this bug.
+      if (Versym && VersymIndex == VER_NDX_LOCAL && Name == "_gp_disp")
+        continue;
+    }
+
     const Elf_Verdef *Ver = nullptr;
     if (VersymIndex != VER_NDX_GLOBAL) {
       if (VersymIndex >= Verdefs.size() || VersymIndex == VER_NDX_LOCAL) {
diff --git a/lld/test/ELF/Inputs/mips-gp-dips-corrupt-ver.s b/lld/test/ELF/Inputs/mips-gp-dips-corrupt-ver.s
new file mode 100644
index 000000000000..42bd32a1e73a
--- /dev/null
+++ b/lld/test/ELF/Inputs/mips-gp-dips-corrupt-ver.s
@@ -0,0 +1,14 @@
+# Source file for mips-gp-dips-corrupt-ver.so
+#
+# % cat gpdisp.ver
+# LLD_1.0.0 { global: foo; };
+#
+# % as mips-gp-dips-corrupt-ver.s -o mips-gp-dips-corrupt-ver.o
+# % ld -shared -o mips-gp-dips-corrupt-ver.so \
+#      --version-script gpdisp.ver mips-gp-dips-corrupt-ver.o
+
+  .global foo
+  .text
+foo:
+  lui    $t0, %hi(_gp_disp)
+  addi   $t0, $t0, %lo(_gp_disp)
diff --git a/lld/test/ELF/Inputs/mips-gp-dips-corrupt-ver.so b/lld/test/ELF/Inputs/mips-gp-dips-corrupt-ver.so
new file mode 100755
index 0000000000000000000000000000000000000000..289ffa538f0c2b5480b0139666f06a4255cd9fec
GIT binary patch
literal 2160
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literal 0
HcmV?d00001

diff --git a/lld/test/ELF/mips-gp-disp-ver.s b/lld/test/ELF/mips-gp-disp-ver.s
new file mode 100644
index 000000000000..efd71684e296
--- /dev/null
+++ b/lld/test/ELF/mips-gp-disp-ver.s
@@ -0,0 +1,13 @@
+# MIPS BFD linker puts _gp_disp symbol into DSO files and assigns zero
+# version definition index to it. This value means 'unversioned local symbol'
+# while _gp_disp is a section global symbol. We have to handle this bug
+# in the LLD because BFD linker is used for building MIPS toolchain
+# libraries. This test checks such handling.
+
+# RUN: llvm-mc -filetype=obj -triple=mips-unknown-linux %s -o %t.o
+# RUN: ld.lld %t.o %S/Inputs/mips-gp-dips-corrupt-ver.so
+
+  .global __start
+  .text
+__start:
+  lw     $t0, %got(foo)($gp)
-- 
2.34.1