[lld] r317741 - [MIPS] Setup less-significant bit in the .got and .got.plt entries in case of microMIPS code

[Simon Atanasyan via llvm-commits]

Author: atanasyan
Date: Wed Nov  8 15:34:34 2017
New Revision: 317741

URL: http://llvm.org/viewvc/llvm-project?rev=317741&view=rev
Log:
[MIPS] Setup less-significant bit in the .got and .got.plt entries in case of microMIPS code

The less-significant bit signals about microMIPS code for jump/branch
instructions.

Added:
    lld/trunk/test/ELF/mips-micro-plt.s
Modified:
    lld/trunk/ELF/Arch/Mips.cpp
    lld/trunk/ELF/SyntheticSections.cpp

Modified: lld/trunk/ELF/Arch/Mips.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Arch/Mips.cpp?rev=317741&r1=317740&r2=317741&view=diff
==============================================================================
--- lld/trunk/ELF/Arch/Mips.cpp (original)
+++ lld/trunk/ELF/Arch/Mips.cpp Wed Nov  8 15:34:34 2017
@@ -191,9 +191,14 @@ template <class ELFT> RelType MIPS<ELFT>
   return RelativeRel;
 }
 
+static bool isMicroMips() { return Config->EFlags & EF_MIPS_MICROMIPS; }
+
 template <class ELFT>
 void MIPS<ELFT>::writeGotPlt(uint8_t *Buf, const Symbol &) const {
-  write32<ELFT::TargetEndianness>(Buf, InX::Plt->getVA());
+  uint64_t VA = InX::Plt->getVA();
+  if (isMicroMips())
+    VA |= 1;
+  write32<ELFT::TargetEndianness>(Buf, VA);
 }
 
 template <endianness E> static uint32_t readShuffle(const uint8_t *Loc) {
@@ -241,8 +246,6 @@ static void writeMicroRelocation16(uint8
   write16<E>(Loc, Data);
 }
 
-static bool isMicroMips() { return Config->EFlags & EF_MIPS_MICROMIPS; }
-
 template <class ELFT> void MIPS<ELFT>::writePltHeader(uint8_t *Buf) const {
   const endianness E = ELFT::TargetEndianness;
   if (isMicroMips()) {

Modified: lld/trunk/ELF/SyntheticSections.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/SyntheticSections.cpp?rev=317741&r1=317740&r2=317741&view=diff
==============================================================================
--- lld/trunk/ELF/SyntheticSections.cpp (original)
+++ lld/trunk/ELF/SyntheticSections.cpp Wed Nov  8 15:34:34 2017
@@ -853,6 +853,8 @@ void MipsGotSection::writeTo(uint8_t *Bu
     Buf += Config->Wordsize;
     const Symbol *Sym = SA.first;
     uint64_t VA = Sym->getVA(SA.second);
+    if (Sym->StOther & STO_MIPS_MICROMIPS)
+      VA |= 1;
     writeUint(Entry, VA);
   };
   std::for_each(std::begin(LocalEntries), std::end(LocalEntries), AddEntry);

Added: lld/trunk/test/ELF/mips-micro-plt.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/mips-micro-plt.s?rev=317741&view=auto
==============================================================================
--- lld/trunk/test/ELF/mips-micro-plt.s (added)
+++ lld/trunk/test/ELF/mips-micro-plt.s Wed Nov  8 15:34:34 2017
@@ -0,0 +1,45 @@
+# Check less-significant bit setup for microMIPS PLT.
+
+# RUN: llvm-mc -filetype=obj -triple=mips-unknown-linux \
+# RUN:         -mattr=micromips %S/Inputs/mips-dynamic.s -o %t-dso.o
+# RUN: ld.lld %t-dso.o -shared -o %t.so
+# RUN: llvm-mc -filetype=obj -triple=mips-unknown-linux \
+# RUN:         -mattr=micromips %s -o %t-exe.o
+# RUN: ld.lld %t-exe.o %t.so -o %t.exe
+# RUN: llvm-readobj -mips-plt-got %t.exe | FileCheck %s
+
+# REQUIRES: mips
+
+# CHECK:      Primary GOT {
+# CHECK:        Local entries [
+# CHECK-NEXT:     Entry {
+# CHECK-NEXT:       Address:
+# CHECK-NEXT:       Access:
+# CHECK-NEXT:       Initial: 0x20009
+# CHECK-NEXT:     }
+# CHECK:        ]
+# CHECK:      }
+
+# CHECK:      PLT GOT {
+# CHECK:        Entries [
+# CHECK-NEXT:     Entry {
+# CHECK-NEXT:       Address:
+# CHECK-NEXT:       Initial: 0x20011
+# CHECK-NEXT:       Value: 0x0
+# CHECK-NEXT:       Type: Function
+# CHECK-NEXT:       Section: Undefined
+# CHECK-NEXT:       Name: foo0@
+# CHECK-NEXT:     }
+# CHECK-NEXT:   ]
+# CHECK-NEXT: }
+
+  .text
+  .set micromips
+  .global foo
+  .hidden foo
+  .global __start
+__start:
+  lw    $t0,%got(foo)($gp)
+  addi  $t0,$t0,%lo(foo)
+foo:
+  jal   foo0